Polypropylene Injection Molding

Polypropylene injection molding or PP injection molding, is a molding manufacturing technique using polypropylene, which is a type of thermoplastic polymer material that is exposed to heat until it turns to melt. The process forces the low viscosity molten polymer to flow into specially designed molds. On cooling, the liquid turns into a solid plastic and assumes the mold’s shape. This technique is most effective when used on the polymer in its processed form. This technique enables the creation of geometries that would otherwise be challenging to achieve. Curious about polypropylene itself? Now, let’s explore more about polypropylene and its uses, along with the reasons for its popularity in injection molding.

In this article, we will give you a comprehensive description of injection molding polypropylene and discuss the strengths of PP material as well by considering its applications across manufacturing sectors.

Polypropylene injection molding

Types of Polypropylene Used In Molding Applications

The most common types of propylene employed in molding applications include;

1. Homopolypropylene (PP-H)

PP-H, or homopolypropylene is the most used type of polypropylene, characterized by high rigidity and strength as a result of crystalline structure. It is commonly employed in uses where the material will be exposed to a lot of force, as it is with containers, auto parts, and more. PP-H has good chemical and heat resistance hence; it is used in products such as buckets and other household utensils. However, it is less flexible and therefore not as effective in more flexible applications.

2. Random Copolymer Polypropylene (PP-R)

PP-R is a random copolymer polypropylene that contains only a small amount of ethylene, which increases its flexibility and impact strength. This makes PP-R suitable for use in piping systems, automotive parts, and any other consumer goods that are expected to have a long life cycle. Due to these properties, it is commonly used in hot and cold water pipes and containers where strength and flexibility are a requirement.

3. Block Copolymer Polypropylene (PP-B)

PP-B is a block copolymer polypropylene that has a block structure with ethylene thus making it have better impact strength and elasticity compared to PP-A. This type is applied in the automobile industry, in the manufacturing of shockproof packaging material and other heavy-duty consumer products. The automotive sector and protective packaging industries are ideal for PP-B because of its flexibility and damping properties in stressed applications.

Polypropylene Injection Molding: How Does it Work? 

PP Plastic Injection molding provides an advantage of mass production of identical plastic parts. High volumes- from a thousand to millions of identical parts can be produced at one time. Because the intended mold is reused several times in the part’s manufacturing process. This makes polypropylene injection molding another suitable option to meet the large demand and ensure that the products produced are of equal quality, simultaneously.

Process Conditions For Propylene Injection Molding

Table 1: Operational Parameters for pp plastic injection molding.

Parameter 

Specification

Drying RequirementDry at 80-90°C (176-194°F) for 2 hours; moisture level must be under 0.1%.
Melting Temperature Range220-280°C (428-536°F)
Mold Temperature Range20-80°C (68-176°F)
Heat Deflection Temperature (HDT)100°C (212°F) at 0.46 MPa (66 PSI)
Injection Temperature32-66°C (90-150°F)
Tensile Strength32 MPa (4700 PSI)
Flexural Strength41 MPa (6000 PSI)
Density0.91 g/cm³
Injection Molding PressureUp to 180 MPa
Shrinkage Rate1.5-2.0%

Comparison of Polypropylene Grades for Injection Molding

Let’s compare, different injection molded polypropylene grades for the molding process.

Table 2: Technical Specifications of different injection molding polypropylene plastic Grades.

Polypropylene TypeTensile StrengthElongation at BreakFlexural RigidityHeat ResistanceNotable Features
Pro-fax 63234,930 psi11%210,000 psi199.0 °FGeneral-purpose, resists stress cracks
Pro-fax SG7022,900 psi6%150,000 psi180.0 °FImpact-resistant, suitable for automotive use
Pro-fax 65234,790 psi12%200,000 psi190.0 °FStiffness, ideal for food packaging
Pro-fax PD7024,500 psi12%170,000 psi190.0 °FMaintains dimensions well, easy to process
FHR P5M6K-0483,900 psi11%153,000 psi183.0 °FClarity-enhanced, visually appealing

Polypropylene Injection Molding

Design Guidelines for Polypropylene Injection Molding Parts

Molding of polypropylene is easy, but to get the best result, one has to follow certain design principles. This section focuses on the practical recommendations that are necessary to produce long-lasting and high-performance polypropylene components.

Living Hinges Key Factors

When designing living hinges in polypropylene, it is good to work at a thickness of between 0.2 mm to 0.51 mm. For optimum performance, the radii should be wide and the hinge should have a flat shoulder. This design approach provides flexibility and strength to withstand the usage of the hinge when used several times.

Guidelines for Wall Thickness

In the case of polypropylene parts, the thickness of the walls of the product must not exceed 0.635 mm to 3.81 mm thickness. Thick parts should also have smooth changes in thickness from one level to another to avoid defects such as sink marks. Moreover, ribs should preferably be less than half the thickness of the adjoining walls to provide strength and prevent the formation of structural voids.

Radii in design

Radii in the mold design also assists in reducing stress concentrations. So, it significantly impacts the life cycle of the part. The suggested radius should be at least twenty-five percent of the wall thickness. The radius of curvature should be 75% of the thickness of the wall which gives both the strength and the fine surface finish.

Draft Angle Recommendations

Polypropylene can take very small angles of drafting, as small as one degree, which is adequate for most parts. But if your part has textured surfaces, it’s recommended to increase the draft angle up to five degrees depending on the depth of the texture. In the case of filled polypropylene materials, it may be necessary to have a draft angle of up to ten degrees to facilitate easy ejection of the part and to improve the quality of the final part.

Setting Part Tolerances 

Requirements for tolerance of polypropylene parts can be classified into commercial tolerance or fine tolerance. Commercial tolerances are relatively larger and cheaper as compared to fine tolerances which are precise but expensive. For instance, a commercial tolerance for a 20 mm part will be in the region of ± 0.125 mm, while the fine tolerance for the same part is about 0.075 mm. Thus, it’s crucial to understand that if tighter tolerances are desired they can have a large impact on the production cost.

Polypropylene Material Processing

Polypropylene has a melting point within the range of 160-170°C and this means that correct temperature control is required while processing the material. Additionally, it is crucial to dry the polypropylene pellets for the injection molding process. For optimal outcomes and splay-free parts, the moisture must be kept below 0.02%.

Injection Molding

The PP injection molding temperature is needed around 220°C and 280°C while the mold temperature is between 30°C and 80°C. These conditions are as follows to have proper flow and solidification. Cycle time is another critical consideration. Usually, it refers to the time taken to complete a cycle and it should be reduced to avoid warping, and efficient cooling is important. In addition, cooling channels must be designed in such a manner that allows equal distribution of heat all over the surface.

Extrusion Processing

Extrusion is carried out by melting Polypropylene at a temperature of 210°C to 250°C. Temperature control and cooling rate are two critical factors that need to be well controlled to allow the formation of the desired product properties.

The extrusion die is a critical component in the process. It has to be designed to not allow the die to swell and control the flow of the material that is being extruded to achieve the desired quality of the final product.

Blow Molding

The blow molding process involves heating polypropylene and then forming it into a parison and blowing it in a mold. Temperature and inflation pressure should be strictly maintained to produce the desired shape of the product. Ejection Part cooling is required to retain the part shape and dimensions. The cooling rate should be dependent on the size and complexity of the part in question.

PP injection molding

Quality Inspection:

The two areas that are of particular importance include;

  • Sanitary and Storage Procedural Measures The Purity of polypropylene depends on handling and storage procedures and clean equipment.
  • Quality Control Periodical examination during processing helps to ensure that the material and the final products are of the right quality and standard and meet the requirements.

What are The Benefits of Propylene Injection Molding?

The following are the benefits of polypropylene injection molding:

  • Affordability: Polypropylene injection molding is relatively cheap and more so for productions that will require large quantities. The process has a low material cost and little wastage since the material that is in excess can be reused in the system. This efficiency means that large production volumes are offered at cheaper unit prices than would be in the case of smaller production volumes.
  • Short Cycle Time: The injection molding process can produce high volumes of parts in the shortest time possible. Polypropylene has good thermal properties and hence the molds can be filled and cooled quickly enhancing the production rates and lead times.
  • Superior Chemical Resistant: Polypropylene is highly resistant to a vast number of chemicals such as acids, alkalis, and organic solvents. This property makes it suitable for use in applications in extreme conditions including car parts and chemical vesse.
  • Least Impact: Polypropylene has less impact strength as compared to HDPE, however, copolymer polypropylene has good impact strength. This makes it a preferred choice for products that require mechanical strength and resistance to impact, for example, automotive and durable consumer goods.
  • Dimensional Stability: Once it has been cooled, polypropylene has high dimensional stability. This stability is very essential to guarantee that the molded parts are fitting correctly and performing their intended tasks without requiring further modification.
  • Low Moisture Absorption: Polypropylene has little or no capability to absorb moisture and therefore the strength and dimensions of the material do not change when exposed to different humidity levels. This property makes this property suitable for use in applications where the material is exposed to moisture most of the time.
  • Flow Characteristics: Due to the favorable flow characteristics it is easier to process polypropylene and this makes the molding process easier. It makes it possible to produce large quantities of molded products and also helps overcome the typical problems with molding, such as warping or lack of filling.

What are the Limitations of Propylene Injection Molding?

Some of the demerits of Polypropylene Injection Molding include the following;

  • High Thermal Conductivity: Polypropylene has a low heat resistance and thus it cannot be used in high-temperature areas. Polypropylene has poor thermal stability and the parts made from it may deform or lose their strength at temperatures above 100°C (212°F).
  • UV Stability Polypropylene is not very resistant to UV light and when exposed to UV light for long, it undergoes degradation by fading to an undesirable color, becoming brittle, and exhibiting low mechanical properties. This limitation makes it necessary to use UV stabilizers or coatings especially when the product is to be used outside.
  • High Shrinkage Rate: As much as 1.5% to 2.0% of polypropylene shrinks, the parts made from this material may warp or undergo dimensional changes if not well controlled. This can also influence the quality of the final product because the performance of the product can be compromised where precision is required.
  • Not Suitable for High Stress Application: Although polypropylene has good impact strength it does not offer high strength and stiffness. In applications where high tensile or flexural loads are applied on the part, PP may not offer sufficient strength.
  • Limited Ability to Produce Small Features: While polypropylene has many uses, it is not easy to produce very small features and intricate details. The flow characteristics of the material and the cooling properties may reduce the level of detail in very fine designs.
  • Less number of colors available: Polypropylene has fewer choices of colors as compared to other plastics in the market. Striking specific or even desired shades may be possible only with the help of colorants or other kinds of treatments.

Common Parts Manufactured by Polypropylene Injection Molding

Propylene injection molding commonly produces the following parts:

  • Dashboard Panels
  • Glove Compartments
  • Mirror Housings
  • Plastic Containers
  • Kitchen Utensils
  • Food Containers
  • Crates and Pallets
  • Medical Device Housings: Lots of medical injection molding parts made from PP material.
  • Plumbing Pipes
  • Toys: Many of plastic injection molding toys made by ABS and PP materials.

Gates and runners in polypropylene injection molding tool

In polypropylene injection molding, gates and runners constitute some of the most important features that control the flow of the molten material into the mold cavity. The design of these elements should enable proper filling, and the quality of the finished parts should be very high.

Polypropylene injection molding shop

Sprue Design

The sprue serves as a conduit for molten polypropylene, connecting the injection molding machine to the mold cavity. This is a cylindrical design with a spherical part at the end that fits properly into the machine nozzle. This is critical to prevent leaks and ensure a smooth flow of materials through the system and equipment.

Runner System

Molten polypropylene travels through runners from the sprue to the mold cavity. Molds with multiple cavities design their runners with branches to evenly distribute the material. We suggest employing cold slugs at junctions to prevent early stiffening and ensure free flow. The runner diameters range from 4 to 7 mm to ensure that there is optimal flow and cooling for the mold. 

Gate Functionality

Gates are the last opening through which molten polypropylene is allowed to flow into the mold cavity. The dimensions and the kind of gate determine how the material is transported throughout the manufacturing process and the quality of the last part. They are pin gates and edge gates and they are chosen depending on the type of mold that is to be made. The gate should allow for easy flow of materials into the mold while at the same time reducing the formation of surface defects.

Gate Sizing and Placement

Small gates are normally used to minimize friction and prevent the wear out of the material. The thickness of the gate land is the part of the gate that joins the cavity should be as thin as possible so that it can be easily filled. Gate location is important, usually located at the thickest section of the mold to achieve an even spread of material and minimize defects.

Design Considerations

Some of the common problems such as sink marks and poor filling can be solved through proper gating and runner systems. To improve production efficiency and part quality, updating the designs at some intervals based on the best practices and feedback on the process is effective.

Industry Applications of Propylene Injection Molding

PP injection molding often finds its applications across various manufacturing sectors;

Food Packaging

Polypropylene is widely used in food packaging since it is safe and has a longer lifespan. Take-out containers and food storage products such as cups and containers are made from PP foam for thermal insulation and protection. PP material is used in making plastic cups and bottles for beverages and food products since the material does not react with moisture or chemical substances.

Consumer Goods

In the consumer goods industry, polypropylene is preferred for its strength and the ability to be molded. PP is used in small appliances like blenders and hairdryers because it offers impact strength and ease of molding. Polypropylene is safe and durable and it is used often in injection molding toys. Furthermore, polypropylene’s durability is also used in household products such as bins for storage and utensils in the kitchen.

Automotive

The automotive industry is one of the major users of polypropylene as the material is light in weight and has a high degree of strength. PP is utilized in interior trim parts such as dash and panels due to the material’s versatility in terms of appearance and durability. There are also polypropylene glove compartments and mirror housings to give the needed strength and impact protection.

Textiles

It is common knowledge that polypropylene fibers are essential in different textile areas because of their strength and resistance to stains. PP fiber carpets are capable of withstanding wear and stain. PP is used for furniture and automotive interiors since it does not wear out easily and is easy to clean. Due to its excellent characteristics, polypropylene fibers are used in the production of clothing that wicks moisture, providing comfort and performance.

Packaging Films

One of the most important types of packaging films is polypropylene films because of the strength and flexibility that they offer. The applications of BOPP (Biaxially Oriented Polypropylene) films are in packaging due to their high clarity, excellent mechanical properties, and moisture and oxygen barrier properties. CPP (Cast Polypropylene) films are used for heat sealability in flexible packaging applications for a variety of products.

Pipes and Fittings

Polypropylene pipes are used in plumbing and industrial practices since they are chemically inert and can be easily installed. PP plumbing pipes are used for both hot and cold water because of their strength and resistance to corrosion. In industrial applications, the use of polypropylene pipes is in chemical and waste handling systems, and the material is well endowed with the strength and capability of withstanding aggressive conditions.

Summary

This article gives more information about polypropylene (PP) as an engineering plastic, including the different types available, the properties of the PP, and the complexities of the injection molding process. It also examines the challenges associated with selecting the right equipment, addressing issues related to product design, and discussing the fundamentals of mold design. In the same vein, the article discusses some of the major defects that are likely to occur during production and how to correct them.

OEM contact manufacturer

To ensure the best PP material and injection molding production, it is wise to seek advice from an experienced supplier. An experienced provider can provide recommendations on the most suitable PP plastic injection moldings for your product’s functional requirements and the final product’s appearance, ensuring a successful project.

FAQs – Polypropylene Injection Molding

Q1. What are the major categories of polypropylene Pallets for injection molding?

They include Homopolypropylene (PP-H) for rigidity, Random Copolymer Polypropylene (PP-R) for flexibility, and Block Copolymer Polypropylene (PP-B) for impact resistance.

Q2. What should be done to polypropylene before molding?

Polypropylene has to be dried at 80-90°C for not less than 2 hours to bring the moisture content to below 0.1% reduction in molding quality is achieved to avoid the formation of poor-quality products.

Q3. What are some of the problems that may occur in polypropylene injection molding?

Some of the most common imperfections are sink marks, flowlines, venting issues, warping, and incomplete filling. These problems can be solved by adjusting the thickness of the wall, increasing venting groove, the temperature of the mold, and the pressure of injection.

 

 

TPE injection moulding

Plastic injection molding is a widely used manufacturing process. In today’s world, this method has become essential for producing large-scale plastic parts. Its popularity is due to its fast, accurate, and highly efficient operation.

Plastic injection molding typically allows you to create countless plastic items. Most of these plastic parts are your daily items, from your smartphone casting to the handle on your toothbrush.

Plastic injection molding allows you to make thousands, even millions, of identical parts. Of course, these plastic parts come with tight tolerances up to 0.01mm. This level of precision creates accurate designs and products that make the product effective and look good. Injection-molded products are widely used in the car, consumer goods, and electronics industries. 

Plastic injection molding involves several key stages. Each stage here is critical. In this article, we’ll dive into these stages so you can see how products go from raw plastic to ready-to-use parts. Moreover, you’ll learn about the plastic injection molding services offered in a factory. This article will be a comprehensive guide, so let’s get started.

What Is Plastic Injection Molding?

Injection molding is a prevalent manufacturing method. The term is divided into “injection” and “molding.” As the name indicates, this process entails injecting material into a mold. Plastic injection molding refers to the use of plastic.

This method shapes parts of various designs by injecting the molten material into the plastic injection mold. It is widely used to make plastic parts quickly and accurately. Once the mold is ready, you can create hundreds or millions of plastic parts. The process is highly efficient and offers consistent quality. As a result, people prefer this method to create complex shapes and precise details.

This procedure is not limited to plastic toy pieces or containers. Plastic injection molding is critical to numerous industries. Take the auto industry, for example. Almost every vehicle on the road today features injection-molded components, such as dashboards.

Electronics such as laptops, smartphones, and more depend significantly on this process. Most of their internal components, casings, and joints are injection molded.

In the medical industry, accuracy is essential, and injection molding delivers just that. The process yields precise tolerances for surgical tools, syringes, and other medical items.

Then there’s the consumer goods industry. Injection molding mostly makes our everyday items. Typical examples are kitchen utensils, plastic jars, bottles, furniture, food containers, and more.

plastic injection molding company

Benefits of Plastic Injection Molding Compared to Other Methods

There are various types of plastic-forming methods. Some popular ones are extrusion molding, compression molding, blow molding, and rotational molding. Now, what are the benefits you can get from the plastic injection molding method?

Precision and Complexity

One of the best things about plastic injection molding is precision and complexity. Extrusion molding or compression molding typically deals with simpler shapes. Therefore, these methods are not suitable for complex shapes.

Plastic injection molding, on the other hand, can handle more complex geometries with related mold structure. This method also allows you to work with thin walls, tight tolerances, and small and fine details. You can get the highest quality plastic products compared to any other methods.

High Production Speed

Time is valuable, especially in manufacturing. Plastic injection molding is built for speed. Once the injection mold is set up, it can produce parts rapidly, much faster than traditional or blow molding. This speed makes plastic injection molding process a go-to option for high-volume production. It’s one of the fastest methods out there.

You will be surprised to learn that plastic injection molding can make thousands of plastic parts in an hour. This method can save time and money simultaneously.

Minimal Waste

Plastic injection molding is efficient in material use. If you can make the mold correctly and precisely inject the plastic, you can minimize excess plastic—extrusion molding, where continuous material flow often leads to scraps.

In plastic injection molding, the extra plastics can be used further, reducing injection molding costs and contributing to a green environment.

Consistent Quality

Plastic injection molding also ensures uniform products. One plastic injection mold can produce millions of plastic products with the same shape and properties. It’s tough to achieve exact uniformity with compression and blow molding, but you can do it precisely with injection molding. It reduces the cost and meets the demand for high-quality products.

Versatile Material Choice

There are many types of plastics out there that are widely used in many applications. They are not all the same, and each type has its unique application. Injection molding can easily accommodate a wide range of materials. This flexibility allows you to meet a specific need. This means you can meet exact strength, durability, and flexibility properties.

Superior Finish

Injection molding creates parts with smooth surfaces and a clean finish. This method eliminates or reduces the need for post-processing. Rotational molding, on the other hand, is pretty tricky and requires extra finishing.

plastic injection molding

What is an Injection Molding Machine?

A plastic injection molding machine is a simple piece of equipment. It has several vital components that work together to produce plastic parts. In general, there are three central units in a plastic injection molding machine. Each element plays a crucial role in the plastic injection molding process.

Clamping Unit

The clamping unit holds the mold tightly in place during the injection process. It acts as a grip so the mold doesn’t slip, allowing you to change it based on the final product design.

When the machine begins, the clamping unit closes the mold halves. It uses high pressure, primarily hydraulic pressure, to prevent plastic from leaking during injection.

After the part cools, the clamping unit opens the mold to release the finished product. Without this unit, the process would be a mess.

Injection Unit

The injection unit, on the other hand, is the heart of the machine. It melts the plastic granules and injects them into the mold. The injection unit has a hopper that feeds the plastic into a heated barrel. The material is melted inside the barrel until it reaches a liquid state. Then, a screw or plunger pushes the molten plastic into the mold.

Control Unit

Note that this whole process must be appropriately controlled. Otherwise, the final product might get messy. For example, temperature control is critical in this process. You must set the temperature at the right level so that your final product doesn’t have defects. On the other hand, injection time, ejection time, and pushing force should also be adequately controlled.

What is Injection Mold?

As mentioned in the previous section, the clamping unit typically holds the injection mold. The injection mold is part of the clamping unit and shapes molten plastic into specific forms.

Injection molds are commonly made of tool steel. A variety of tool steels can be used to make injection molds. P-20 28-30 RC, S-7 pre-hardened tool steel 56 RC, H-13, and 420 are noteworthy. These tool steels are strong and durable, and the material must be strong enough to withstand millions of plastic products.

An injection mold comprises two essential parts: the cavity and the core. The cavity is the hollow space that the plastic occupies. It determines the outward form of the component. The core, on the other hand, determines the interior details. Together, they create a complete part.

You can realize the importance of a high-quality mold in making plastic injection-molded parts. The quality of the injection mold also determines the quality of the final parts. Therefore, you must first ensure the quality of the injection mold.

A well-designed mold leads to fewer defects and reduces production time and costs. Poor design may result in warping and inconsistent quality. So, seeking professional help when designing your first injection mold is wise. 

what is plastic injection mold

How Does Injection Molding Work?

You have already gone through a comprehensive study of injection molding. You are also familiar with the various components of an injection molding machine. In this section, you will learn how injection molding works.

Clamping

The first step in the injection molding process is clamping. Here, the two halves of the mold are brought together. This is the crucial stage. If the mold isn’t clamped tightly, molten plastic can escape, which may create defects in your final parts.

The clamping unit holds the mold halves together with significant force. The force or pressure must be strong enough to withstand the pressure of the injected material. If it’s too weak, the mold will open during injection, causing a mess. Too much force can damage the mold.

So, how do you determine the correct clamping force? Consider aspects such as the part’s size and the plastic utilized. For example, bigger pieces need more force. The goal is to get a tight fit without overdoing it. Once the mold is firmly closed, we proceed to the next step.

Injection

The plastic material is fed into the injection molding machine at this stage. The raw plastic, usually in pellet form, is heated until it melts into a thick, gooey substance.

It is pouring syrup into a mold. The molten plastic is poured into the mold cavity under high pressure, ensuring that it fills every nook and corner. If the pressure is too low, the mold cannot fill. It is important to note that improper pressure might result in weak or incomplete portions.

Speed is also critical during injection. The faster the material is injected, the less time it has to cool before filling the mold. But there’s a problem. Doing it quickly can create turbulence, the main cause of a few defects. Therefore, you must carefully balance speed and pressure.

Dwelling

The dwelling phase is also critical in the plastic injection molding method. As you know, you must maintain appropriate pressure while filling the mold. When the plastic is injected, it doesn’t always fill the mold evenly. There might be air pockets or gaps. To avoid this issue, you must hold the pressure steady. This way, you can ensure no trapped air inside. This is where the dwelling phase comes in.

The dwelling time can vary depending on the material and part design. Too short a dwelling time can lead to incomplete parts, while too long can waste time and energy.

Cooling

Once the dwelling phase is complete, it’s time for cooling. This is where the real transformation happens. The molten plastic begins to solidify as it cools. The cooling stage must be maintained properly to set the shape of the part.

This stage usually takes longer than the dwelling stage. In this case, the mold’s temperature generally plays the leading role. You could use an air or water cooling system. Warping might happen if the mold is too cold, so be careful!

Mold cooling system

Mold Opening and Removal of Products

After cooling, it’s time to release the final part. Usually, the ejector pin does this. The clamping unit releases the pressure, generally allowing the two halves to separate. If you do it incorrectly, it can damage the mold or the finished part.

Once the mold is open, you can remove it using tools or hand. Once removed, the part is inspected again. It might undergo further processing, such as trimming or surface finishing.

Plastic Injection Molding Materials

One of the best benefits of plastic injection molding is its versatility. You can generally work with various plastic injection molding materials in injection molding manufacturing. Selecting the suitable material from this diverse list depends on your project needs. Remember, each material here has its unique strengths and weaknesses. Do you need flexibility? Go for PE or PP. Want Toughness? Try ABS or PC.

injection molding material

Polyethylene (PE)

This plastic is incredibly lightweight and flexible. It is also very resistant to chemicals and moisture, making it a popular choice for containers and bottles.

Polyethylene is one of the most widely used plastics globally due to its incredibly lightweight, flexible and cost-effectiveness. It is also very resistant to chemicals and moisture, making it a popular choice for containers and bottles.

There are various type of PE materials, including Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE), and Ultra-High Molecular Weight Polyethylene (UHMWPE), each one uses to different applications but very similar.

Properties: Lightweight, flexible, moisture-resistant, and resistant to many chemicals. PE is relatively soft but has good impact resistance. It can handle low temperatures but has limited resistance to high temperatures.

Types of PE materials:

  • LDPE: Known for its flexibility, commonly used in film applications like plastic bags.
  • HDPE: Stronger and more rigid, used in items like milk jugs, detergent bottles, and pipes.
  • UHMWPE: Extremely tough with excellent wear resistance, often used in industrial applications, such as conveyor belts and bulletproof vests.

Applications: Due to its variety, PE is used across industries for containers, piping, and even high-wear applications. In the food industry, it’s ideal for food containers, food packaging due to its moisture resistance. Go to PE injection modling and HDPE injection molding page to know more about this PE material.

what is TPE material

Polypropylene (PP)

Polypropylene is another popular choice. It is prevalent for being strong and very resistant to fatigue, it provides excellent temperature resistance.It’s available in homopolymer and copolymer forms, with each variation suitable for specific applications.

Properties: Strong, durable, fatigue-resistant, and excellent temperature resistance. PP can endure repetitive bending, making it suitable for applications like living hinges.

Advantages: PP offers high chemical resistance and is lightweight, yet stronger than PE. It’s also resistant to absorbing moisture, making it ideal for long-lasting products.

Applications:

  • Automotive: Frequently used in automotive parts like bumpers, dashboards, and battery cases.
  • Consumer Goods: Found in reusable containers, furniture, textiles, and packaging. Its fatigue resistance makes it useful for hinges in household products and storage containers.
  • Medical: Sterilizable and resistant to bacteria, PP plastic material is also common in medical syringes and vials. Go to polypropylene injection molding page to know more.
PP injection molding

Acrylonitrile Butadiene Styrene (ABS)

ABS is a plastic used for injection molding. It is known for its toughness, making it great for parts that need to endure impact. It has a glossy finish, so it’s often used in electronics and toys. ABS might be your best bet if you want something that looks good and lasts.

Properties: ABS is tough, impact-resistant, and lightweight with a glossy finish. It’s also relatively affordable, combining strength and visual appeal.

Advantages: Known for excellent impact resistance, making it ideal for products that must withstand rough handling. ABS is also highly machinable and easy to paint, providing aesthetic and functional versatility.

Applications of ABS plastic products:

Electronics: Used for casings, keyboards, and monitor housings due to its aesthetic finish and durability.

Automotive: Instrument panels, wheel covers, and mirror housings.

Toys and Consumer Products: Especially popular for toys (such as building blocks) that require durability and a pleasing appearance. Go to ABS injection molding and what is ABS material page to know more about this material.

ABS materials

Polycarbonate (PC)

This plastic material is relatively heavier than other plastics. This material could be your best choice when you need a durable solution. It is virtually unbreakable and highly transparent. This material is used in safety glasses and light fixtures. It’s a strong option when transparency and resilience are needed.

Properties: Polycarbonate is heavier than most plastics but is virtually unbreakable and highly transparent. It can withstand high impact and heat, making it suitable for safety applications.

Advantages: It’s one of the strongest transparent plastics available, with excellent heat resistance. It’s also easily molded, allowing for intricate designs in parts and components.

Applications:

Safety Equipment: Used for safety glasses, helmets, and shields due to its shatter-resistant quality.

Optical Media: Common in lenses and DVDs because of its clarity.

Construction and Lighting: Used in skylights, lighting fixtures, and bulletproof glass for durability and transparency. Go to polycarbonate injection molding and Polycarbonate vs Acrylic pages to know more about this PC plastic material.

Polycarbonate Injection Molding

Nylon (PA)

Nylon is a plastic material with excellent strength and flexibility. It is also very resistance to wear and abrasion. Available in different grades (Nylon 6, Nylon 6/6, etc.), each with specific properties, it is widely used in industrial applications requiring toughness. It can also handle high temperatures.

Properties: Excellent strength, flexibility, abrasion resistance, and wear resistance. Nylon can withstand high temperatures and provides good chemical resistance.

Advantages: Nylon’s high durability and heat resistance make it a top choice for mechanical parts, while its low friction makes it suitable for gears and bearings.

Applications:

Mechanical Components: Often used in gears, bearings, bushings, and other wear-prone parts due to its strength and durability.

Textiles: Common in fabrics due to its strength and resilience, often used in outdoor gear and apparel.

Automotive: Used in engine components, fuel tanks, and under-the-hood parts due to its heat resistance. Go to nylon injection molding page to know more.

Every single plastic provides specific advantages that make it ideal for particular applications. Selection depends on factors like strength requirements, environmental conditions, aesthetic preferences, and manufacturing costs. This guide helps in understanding which plastic might be best suited for various product requirements across different industries, from consumer goods to industrial components.

PA66-GF30 plastic

Plastic Injection Molding services

A typical plastic injection molding factory can offer you unique services. Each of these services might benefit you in your business. This section will familiarize you with a few plastic injection molding services.

plastic injection molding service

Service #1 Design and Engineering Support

Designing and engineering support are crucial parts of mold and product design. A perfect injection mold can ensure effective injection and the highest quality of the products. Every mold manufacturing company specializes in this to meet specific customer demands. The engineering team collaborates with clients to optimize part designs.

This way, they can ensure good manufacturability and the efficiency of the whole process. They also evaluate the initial design and suggest changes to save time and reduce costs.

DFM is a term used to manufacture plastic injection molds. Design for manufacturability focuses on how easy or difficult a design is to manufacture. It helps identify potential issues early in the process. By implementing DFM principles, designers can reduce production hiccups. You will know this when you deal with the actual injection mold design process.

Service #2 Custom Mold Making

Custom mold making is another primary service of an injection molding company. To launch new plastic products, you must start by creating a custom plastic injection mold.

The mold-making process starts with the design and engineering steps. What shape do you need? How thick should the walls be? These questions guide the mold design steps.

Several other factors also play a crucial role here. First is the material choice. As mentioned already, injection molds are typically made of high-quality tool steels. When making the molds, tolerance is the most critical parameter. Therefore, the manufacturing method must be wisely chosen.

The two most popular injection mold-making methods are CNC machining and casting. CNC machining can be of various types. Based on your design, the CNC method varies. Sometimes, you may need multiple CNC machining methods. For instance, CNC milling creates grooves, holes, and inner shapes. Other CNC methods include CNC turning, boring, drilling, and more.

Metal casting is another method of making injection mold cavity or core, this is specially used in plastic doll toys related products. It is pretty complex and requires careful consideration to make any type of plastic injection molds. CNC machining and EDM (electric discharge machining) are two popular manufacturing process of creating plastic injection molds.

Service #3 Custom Plastic Parts

You might not have the facility to install custom molds. On the other hand, making such facilities might need high costs. Because of this, most injection molding manufacturers also offer to make various custom plastic parts. This way, you can save a lot of investment costs and make money faster, you only need to buy the injectino molds and send your molds to your plastic injection molding supplier, they will make all of custom palstic products base on your customized injection mold.

This process also starts with a clear design. Once the mold is ready, plastic is injected at high pressure into the mold. As the plastic cools and solidifies, the part takes shape. You already know the benefits and detailed manufacturing process.

Service #4 Quality Control and Testing

A plastic injection molding company offers testing and quality control services in addition to the above three services.

Quality control is crucial in injection molding. It’s the safety net that catches upcoming issues when they happen. Various quality control processes might be needed depending on the mold and its products.

Dimensional checks are one of the first lines of testing. This process measures parts against specified tolerances. Are they the right size? Do they fit together as they should? If not, the engineers make necessary adjustments before mass production. Strength testing is the next testing method. This testing method ensures that parts can withstand their intended use. Besides, there are other tests like surface finishing, pressure testing, spur testing, defects testing, and many more.

Frequently Asked Question

How Much Does Injection Molding Cost?

The cost of injection molding generally varies based on design and size—the average ranges from $1000 to $5000. If you need larger molds, the cost might be higher. The cost of injection-molded plastic parts, on the other hand, depends on the type of material. PC plastic is generally more expensive than PVC or ABS. 

What Is The Problem With The Injection Molding Process?

Every process has its hiccups, and injection molding is no exception. Common problems include warping, which occurs when the part cools unevenly.

Flash is another problem with the injection molding process. It is the excess material that seeps out of the mold. Have you seen unwanted edges on your plastic parts? If yes, then it’s a sign of flash. In contrast, shorts happen when the mold doesn’t fill completely.

How Long Does It Take to Make A Plastic Mold?

The time it takes to create a plastic mold can range from a few weeks to several months. The specific time is not fixed. It all depends on the complexity and the specifics of your project.

How Do I Add Texture to The Mold?

Adding texture to a mold can improve your product’s look. It’s all about aesthetics and function. There are several methods to do it. One of the popular ways is etching, which creates patterns on the mold’s surface before it’s used. Another option is laser engraving.

Electronic Product Design And Manufacturing

Final Words

Plastic injection molding is one of the most popular plastic manufacturing processes. It is an efficient way to make complex, high-precision plastic parts. Throughout this article, we talked about this process, especially plastic injection molding.

We are among the top 10 plastic injection molding companies in China, specializing in plastic injection mold and injection molding manufacturing, and we export plastic parts from China to various contries of the world. Over 40 happy customers have provided us with the best quality, and they are fully satisfied by our quality and service. You are welcome if you need our support. We sincerely hope we could service you in the near future, and you will be surely happy as well as our other happy customers.

The production of thermoplastic plastic products involves a variety of commercial methods. Each has its own specific design requirements as well as limitations. Usually, part design, size, and shape clearly determine the best process. Occasionally, the part concept lends itself to more than one process. Because product development differs depending upon the process, your design team must decide which process to pursue early in product development.

This section briefly explains the common processes used for thermoplastics from Bayer Corporation. Today, many companies purchase injection-molded parts from injection molding companies in China. If you need injection molded parts for your business, you need to really think about this.

The above-described injection molding process uses an injection molding machine to manufacture plastic products. There are two main parts to the machines: the injection unit and the clamping unit. Please visit our injection molding section for further information.

Are you in need of injection molding, or are you seeking a China-based injection mold partner to create plastic molds and manufacture your plastic molded parts? Send us an email, and we will reply to you within two working days.

Injection molding company

We are one of the top 10 plastic injection molding companies in China that provides custom injection mould and injection moulding manufacturing services for a variety of plastic products around the world. We offer part design, mold design, PCB design, prototypes,  mold making, massive production, testing, certificates, painting, plating, silkscreening, printing, assembly, and delivery, all in one-stop services.

Do you know the name of the process by which most plastic-solid materials are produced? It is called injection moulding. It is one of the best molding processes to make millions of injection-molded parts in a very short time. However, the initial injection mold tooling cost is pretty high compared to other machining methods, but this injection tooling cost will be recovered by the large production later, and this process has a low or even no waste rate.

injection molding factory

What is injection molding

Injection molding (or injection moulding) is a manufacturing technology for producing products from plastics. Injecting the molten plastic resin at high pressure into an injection mould, which the mold is made according to the desired part shape, which was created by a designer using some CAD design software (such as UG, Solidworks, etc.).

The mould is made by a mold company (or mold maker) from metal material or aluminum and precision-machined to form the features of the desired part by some high-tech machines like CNC machines, EDM machines, lather machines, grinding machines, wire-cutting machines, etc., step by step to make the final mould cavity base on exactly the desired part shape and size, which we called an injection mold.

The injection moulding process is widely used for producing a variety of plastic products, from the smallest component to the big bumpers of cars. It is the most common technology to produce molding products in the world today, with some commonly made products including food containers, buckets, storage bins, house cooking equipment, outdoor furniture, automotive components, medical components, molding toys, and more.

Injection moulding

Types of Injection Moulding – Basically 7 types of injection molding process as below

Injection moulding equipment

Injection molding machine

Injection molding machines,  normally called injection presses, fasten our custom-made injection mold in the machine. The injection machine is rated by tonnage, which indicates the amount of clamping force that the press can generate. This clamping force keeps the mold closed during the injection molding process. There are various specifications for injection molding machines, from less than 5 tons to 6,000 tons or even bigger.

In general, the basic injection molding machine consists of a mold system, control system, injection system, hydraulic system, and Pinpin system. The tonnage clamp and shot size are used to identify the dimensions of a thermoplastic injection molding machine, which is a major factor in the overall process. Another consideration is the thickness of the mold, pressure, injection rate, the distance between the binding rod, and the screw design.

Injection molding service

Horizontal Injection-molding-machine

Horizontal or vertical machines

There are normally two types of injection molding machines: horizontal and vertical molding machines.

This means molding machines fasten the mold in either a horizontal or vertical position. The majority are horizontal injection molding machines, but vertical machines are used in some niche applications such as cable insert molding, filter injection moldinginsert molding, or some special molding process requirements.Some injection machines can produce two, three, or four colored molded parts at one step; we call them double-shot injection molding machines or 2K injection molding machines (more color will be 3K or 4K molding machines).

Clamping unit

Machines are classified primarily by the type of driving systems they use: hydraulic, electric, or hybrid. Hydraulic presses have historically been the only option available to molders until Nissei introduced the first all-electric machine in 1983. The electric press, also known as Electric Machine Technology (EMT), reduces operation costs by cutting energy consumption and also addresses some of the environmental concerns surrounding the hydraulic press.

Electric injectino molding presses have been shown to be quieter, faster, and have higher accuracy; however, the machines are more expensive. Hybrid injection molding machines take advantage of the best features of both hydraulic and electric systems. Hydraulic machines are the predominant type in most of the world, with the exception of Japan.

Final sumrize for injection molding machine: Injection molding machine converts raw plastic granules or granules into final mold parts using thermoplastic smelting, injection, conditioning, and cooling cycles.

Injection Mold- Types of injection molds

Simply explain that the injection mold is custom made of the desired part shape by cutting the steel or aluminum and producing the mold that can be used in the injection molding machine, which we called injection mold or plastic injection mold. Go to our plastic molding section to learn more about plastic injection mold manufacturing. But making injection mould actually not easy; you need to have a professional team (a mold maker, a mold designer) and mold manufacturing equipment like CNC machines, EDM machines, wire-cutting machines, etc.

There are two main types of injection moldscold runner mold (two plate and three plate designs) and hot runner molds (the more common of the runner-less molds). The significant difference is the presence of sprue and runner with every molded part in the cold runner type. This extra molded component must be separated from the desired molded par;, the hot runner basically does not have any runner wasteore small runner waste.

Cold runner mold

Developed to provide for injection of thermoset material either directly into the cavity or through sprue and a small sub-runner and gate into the mold cavity, there are basically two types of the cold runner which mostly used in the mold industry, two plate mold and Three plate mold.

 

Two plate mold

The conventional two-plate mold consists of two halves fastened to the two platens of the molding machine’s clamping unit. When the clamping unit is opened, the two mold halves open, as shown in (b). The most obvious feature of the mold is the cavity, which is usually formed by removing metal from the mating surfaces of the two halves. Molds can contain a single cavity or multiple cavities to produce more than one part in a single shot. The figure shows a mold with two cavities. The parting surfaces (or parting line in a cross-sectional view of the mold) are where the mold opens to remove the part(s).

In addition to the cavity, there are other features of the mold that serve indispensable functions during the molding cycle. The mold must have a distribution channel through which the polymer melt flows from the nozzle of the injection barrel into the mold cavity. The distribution channel consists of (1) a sprue, which leads from the nozzle into the mold; (2) runners, which lead from the sprue to the cavity (or cavities); and (3) gates that constrict the flow of plastic into the cavity. There are one or more gates for each cavity in the mold.

two-plate cold runner mold

Three plate mold

The two-plate mold is the most common mold in injection molding. An alternative is a three-plate injection mold. There are advantages to this mold design. First, the flow of molten plastic is through a gate located at the base of the cup-shaped part rather than at the side. This allows for a for a more even distribution of melt along the sides of the cup. In the side gate design of the two-plate, the plastic must flow around the core and join on the opposite side, possibly creating a weakness at the weld line.

Second, the three-plate mold allows more automatic operation of the molding machine. As the mold opens, it divides into three plates with two openings between them. This forces the disconnection of runners and parts, which drop by gravity (with possible assistance from blown air or a robotic arm) into different containers beneath the mold.

Three-plate cold runner mold

Hot Runner Mold

Hot-runner molding has parts that are physically heated. These types of molding help transfer the molten plastic quickly from the machine, directly feeding it into the mold cavity. It can also be known as the runner-less mold. The hot runner system is very useful for some of the high volumes of products that will save huge production costs by using the hot runner mold system. The sprue and runner in a conventional two-plate or three-plate mold represent waste material.

In many instances, they can be ground and reused; however, in some cases, the product must be made of “virgin” plastic (original raw plastic material) or there is multiple cavity mold (such as 24 cavities or 48 cavities, 96 cavities, 128 cavities, or even more cavities). The hot-runner mold eliminates the solidification of the sprue and runner by locating heaters around the corresponding runner channels. While the plastic in the mold cavity solidifies, the material in the sprue and runner channels remains molten, ready to be injected into the cavity in the next cycle.

Type of hot runner system.

Basically, there are two types of hot runner systems: one called hot sprue mold (without the manifold plate and hot runner plate), and one called hot runner mold (with the manifold plate and hot runner plate).

Hot sprue mold (without the manifold plate and hot runner plate) uses the hot nozzle (sprue) to feed the material into the mold cavity, either directly or indirectly.

The hot runner mold (with the manifold plate and hot runner plate) means the hot runner system has the hot runner plate, manifold plate, and sub-hot runner sprue. The below pictures are simple explanations for two types of hot runner systems.

Hot runner system

Advantages and Disadvantages of Cold Runner Molding

There are a few amazing advantages to cold-runner molding, such as:

  1. Cold-runner molding is cheaper and easier to maintain.
  2. You are able to quickly change colors.
  3. It has a faster cycle time.
  4. It is more flexible than hot-runner molding.
  5. The gate locations can easily be changed or fixed.

Although there are many advantages, there are also some disadvantages. The disadvantages of cold-runner molding are:

  1. You have to have thicker dimensions compared to the hot runner mold.
  2. You can only use certain types of nozzles, fittings, and manifolds.
  3. Cold-runner molding can result in slower production time when you remove sprues and runners.
  4. You must manually separate the runners and parts after molding.
  5. You may waste the plastic materials if you do not reset after each run.

If you want to know more information, please go to the cold runner mold page to check out more details.

Advantages and Disadvantages of Hot Runner Molding

Hot-runner molding has a few advantages, such as:

  1. Hot-runner molding has a very quick cycle time.
  2. You can save production costs by using hot-runner molding.
  3. Less pressure is needed to inject the molding.
  4. You have more control over the hot-runner molding.
  5. Hot-runner molding can fit a wide variety of gates.
  6. Multiple cavities of mold can be easily filled by using the hot runner system.

The disadvantages of using hot-runner moldings are:

  1. It is more expensive to make the hot runner mold than the cold runner mold.
  2. It is difficult to maintain and fix the hot runner mold.
  3. You are not able to use hot-runner molding on materials that are thermally sensitive.
  4. You will need to get your machines inspected more often than cold-runner molding machines.
  5. It is hard to change the colors in the hot runner mold system.

Want to know more information? Welcome to the hot runner mold section.

Injection Moulding Processing?

Injection molding

Injection molding

Injection moulding is one of the best ways to shape plastic products by injecting a thermoplastic material. During the process of injection molding, the plastic material is placed in the injection molding machine and the melt system of the injection unit is used to melt the plastic into the liquid. The liquid material is then high-pressure-injected into a mold (a custom manufacturing mold) that is assembled in that injection molding machine. The mold is made of any metal, such as steel or aluminum. The molten form is then allowed to cool down and set into a solid form.

The plastic material thus formed is then ejected out of the plastic mold. The actual process of plastic molding is just an expansion of this basic mechanism. The plastic is let into a barrel or chamber under gravity or is force-fed. As it moves down, the increasing temperature melts the plastic resin. Then, the molten plastic is forcibly injected into the mold under the barrel with an appropriate volume. As the plastic cools, it solidifies. The injection-molded parts like this have a reverse shape from the mold. A variety of shapes, both 2D and 3D, can be produced by the process.

The process of plastic molding is cheap due to the simplicity involved, and the quality of the plastic material is modifiable by changing the factors involved in the custom injection molding process. The pressure of injection can be changed to change the hardness of the final product. The thickness of the mold also governs the quality of the article produced.

The temperature for melting and cooling determines the quality of the plastic formed. ADVANTAGES The major advantage of injection molding is that it is very cost-effective and fast. Apart from this, unlike the cutting processes, this process rules out any undesired sharp edges. Also, this process produces smooth and finished products that require no further finishing. Check below for the detailed advantages and disadvantages.

Advantages of injection moulding

Although injection molding is used by many different companies, and there is no doubt this is one of the most popular methods to produce injection molding products, there are some advantages to using it, such as:

  • Precision and aesthetics—because in this injection molding process you can make your plastic part with any shape and surface finish (texture and high gloss finishing), some of the special surface finishing can still be met by the secondary surface finishing process. The injection molding part is the repeatability of their shapes and dimensions.
  • Efficiency and speed: a single production process, even for the most complex products, lasts from a few to several dozen seconds.
    The possibility of full automation of the production process, which in the case of companies dealing with the production of plastic components translates into low production effort and the possibility of mass production,.
  • Ecology: because, compared to metalworking, we are dealing with a significant reduction in the number of technological operations, less direct energy and water consumption, and low emissions of compounds harmful to the environment.

Plastics are materials that, although known relatively recently, have even become indispensable in our lives, and thanks to increasingly modern production processes from year to year, they will contribute even more to saving energy and other natural resources.

Disadvantages of injection molding

  • The high cost of injection molding machines and often the cost of tooling (molds) that equals it result in extended depreciation time and high costs of starting production.
  • Due to the above, injection technology is only cost-effective for mass production.
  • The need for high-qualification technical supervision employees who must know the specifics of injection molding processing.
  • The need for high technical requirements for injection mold making
  • The need to maintain narrow tolerances for processing parameters.
  • A long time of preparation for the production due to the labor-intensive implementation of the injection molds.

Injection molding cycle time

The basic injection cycle time includes mold close, injection carriage forward, plastics filling time, metering, carriage retracts, holding pressure, cooling time, mold open, and eject part(s).

The mold is closed shut by the injection molding machine, and the melted plastic is forced by the pressure of the injection screw to inject into the mold. The cooling channels then assist in cooling the mold, and the liquid plastics become solid into the desired plastic part. The cooling system is one of the most important parts of the mold; inappropriate cooling can result in distorted molding products, and the cycle time will be increased, which will increase the injection molding cost as well.

Molding Trial

When the injection plastic mold has been made by the mold maker, the first thing we need to do is do the mold trial. This is the only way to check the mold quality to see if it was made according to the custom requirement or not. To test the mold, we normally fill the plastics with the molding step by step, using short-shot filling at first, and increasing the material weight little by little until the mold is 95 to 99% full.

After meeting this status, a small amount of holding pressure will be added and holding time increased until the gate freeze-off has occurred. Holding pressure is then increased until the molding part is free of sink marks and the part weight has been stable. Once the part is good enough and has passed any specific technical tests, a machine parameter sheet needs to be recorded for massive production in the future.

Plastic injection molding defects

Injection molding is a complex technology, and problems may happen every time. A new custom made of an injection mold has some issues, which is very normal. To solve the mold issue, we need to fix and test the mold several times. Normally,  two or three trials can completely solve all the issues, but in some cases, only a one-time mold trial can approve the samples. And finally, all of the issues are solved completely. Below are most of the injection molding defects and the troubleshooting skills to solve those issues.

Issue No. I: Short shot defects- What is a short shot issue?

When injecting material into the cavity, molten material does not completely fill the cavity, resulting in the product lacking material. This is called short molding or short shot, as shown in the picture. There are lots of reasons to cause short shot issues.

short shot

Fault Analysis and Method for Correction the defects

  1. Improper selection of injection molding machine: When choosing plastic injection machines, the maximum shot weight of the plastic injection machine must be greater than the weight of the product. During verification, the total injection volume (including the plastic product, runner, and trimming) shall not be more than 85% of the plasticizing capacity of the machine.
  2. Insufficient supply of material: the bottom of the feed position might have “bridging the hole” phenomena. The shot stroke of the injection plunger should be added to increase the supply of material.
  3. Poor flow factor of raw material: improve mold injection system, for example, by proper design of runner location, by enlarging gates, runner, and feeder size, and by using a bigger nozzle, etc. In the meantime, the additive can be added to the raw material to improve the flow rate of the resin or change the material to have a better flow rate.
  4. Overdose of using the lubricant: reduce the lubricant and adjust the gap between the barrel and injection plunger to recover the machine, or fix the mold so that there is no need for any lubricant during the molding process.
  5. Cold foreign substances blocked the runner. This issue normally happens with hot-runner systems. Dismount and clear the nozzle of the hot runner tip, or enlarge the cold material cavity and runner cross-section area.
  6. Improper design of injection feeding system: When designing the injection system, pay attention to gate balance; the product weight of each cavity should be in proportion to the gate size, so that each cavity can be fully filled simultaneously, and gates should be positioned in thick walls. A balanced separate runners scheme can also be adopted. If the gate or runner is small, thin, or long, the molten material pressure will be reduced too much during feeding, and the flow rate will be blocked, which will result in poor filling. To solve this problem, the cross-sections of the gate and runner should be enlarged, and multiple gates should be used when necessary.
  7. Lack of venting: check if there is a cold-slug well or if the position of the cold-slug well is correct. For mold with a deep cavity or deep ribs, venting slots or venting grooves should be added at positions of short molding (end of feeding area). Basically, there are always venting grooves on the parting line; the size of the venting grooves can be 0.02-0.04mm and 5-10mm in width, 3mm close to the sealing area, and the venting opening should be at the end of filling the position.
    When using raw materials with excessive moisture and volatile content, a large amount of gas (air) will also be generated, causing air trap issues in the mold cavity. In this case, raw materials should be dried and cleared of volatile substances. In addition, during the injection process operation, poor venting can be addressed through increasing mold temperature, low injection speed, reducing injection system obstruction and mold clamping force, and enlarging gaps between molds. But the short shot issue happens to the deep rib area. To release the air out, you need to add a venting insert to solve this air trap and short shot issues.
  8. The mold temperature is too low. Before starting molding production, the mold should be heated up to the required temperature. In the beginning, you should connect all of the cooling channels and check if the cooling line is working well, especially for some special materials like PC, PA66, PA66+GF, PPS, etc. The perfect cooling design is a must for those special plastic materials.
  9. Molten material temperature is too low. In a proper molding process window, the temperature of the material is in proportion to the filling length. Low-temperature molten material is poor in fluidity, and the filling length is shortened. It should be noted that after the feed barrel is heated to the required temperature, it should stay constant for a while before starting molding production.
    In the event that low-temperature injection must be used to prevent molten material from being resolved, the injection cycle time can be prolonged to overcome the short shot. If you have a professional molding operator, he should know this very well.
  10. Nozzle temperature is too low. When open mold, the nozzle should be part away from the mold spure to reduce the influence of mold temperature on the nozzle temperature and keep the nozzle temperature within the range of what the molding process requires.
  11. Insufficient injection pressure or holding pressure: injection pressure is close to a positive proportion to the filling distance. The injection pressure is too low, the filling distance is short, and the cavity cannot be fully filled. Increasing the injection pressure and holding pressure can improve this issue.
  12. Injection speed is too slow. Mold filling speed is directly related to injection speed. If injection speed is too low, filling of molten material is slow while slow-flowing molten is easy to cool, hence the flow properties further decrease and result in a short injection. For this reason, the injection speed should be enhanced properly.
  13. Plastic product design is not reasonable. If the wall thickness is out of proportion to the length of the plastic product, the product shape is very complex, and the forming area is large, melt material is easily blocked at the thin wall of the product, leading to insufficient filling. Therefore, when designing the shape and structure of the plastic products, note that wall thickness is directly related to melting limit filling length. During injection molding, product thickness should range between 1-3 mm and 3-6 mm for large products. Generally, it is not good for injection molding if the wall thickness is over 8 mm or less than 0.4 mm, so this kind of thickness should be avoided in design.

Issue No. II: Trimming (Flashing or burrs) Defects

I. What is the flashing or Burrs?

When extra plastic melt material is forced out of the mold cavity from the mold joint and forms a thin sheet, trimming is generated. If the thin sheet is large, it is called flashing.

Molding Flash or burrs

Molding Flash or burrs

II. Fault Analysis and Method for Correction

  1. Mold clamping force is not sufficient. Check whether the booster is overpressurizing and verify whether the product of the projected area of the plastic part and the forming pressure exceed the clamping force of the equipment. Forming pressure is the average pressure in the mold; normally, it is 40 MPa. If the calculation product is larger than the mold clamping force, it indicates that the clamping force is insufficient or the injection positioning pressure is too high. In this case, the injection pressure or section area of the injection gate should be reduced; pressure keeping and pressurization time can also be shortened; injection plunger strokes can be reduced; the number of injection cavities can be reduced; or a mold injection machine with a larger tonnage can be used.
  2. The material temperature is too high. The temperature of the feed barrel, nozzle, and mold should be decreased properly to reduce the injection cycle. For melts of low viscosity, like polyamide, it is difficult to solve overflow flashing defects by simply changing injection molding parameters. To solve this issue completely, fixing the mold is the best way, like doing better mold fitting and making the parting line and shot-off area more precise.
  3. Mold defect. Mold defects are the main reason for overflow flashing. The mold must be carefully examined and the mold parting line re-verified to ensure the pre-centering of the mold. Check whether the parting line fits well, whether the gap between sliding parts in the cavity and core is out of tolerance, whether there is adhesion of foreign matter on the parting line, whether the mold plates are flat and whether there is bending or deformation, whether the distance between mold pate is adjusted to fit the thickness of the mold, whether the surface mold block is damaged, whether the pull rod is deformed unevenly, and whether the venting slot or grooves is too large or too deep.
  4. Improperness of the molding process. If injection speed is too high, injection time is too long, injection pressure in the mold cavity is unbalanced, mold filling speed is not constant, or there is overfeeding of material, an overdose of lubricant can lead to flashing; therefore, corresponding measures should be taken according to the specific situation during operation.

Issue No. III. Welding Line (Joint Line) Defects

I. What is the welding line defect?

Welding line

Welding line

When filling the mold cavity with molten plastic material, if two or more flows of molten material have cooled down in advance before confluence t the joint area, the flows will not be able to totally integrate and a liner is produced at the confluence, thereby a welding line is formed, also called joint line

II. Fault Analysis and Method for Correction

  1. The material temperature is too low. Low-temperature molten material flows have poor confluence performance, and the welding line is easily formed. If welding marks appear at the same position on both the interior and exterior of a plastic product, it is usually inappropriate welding caused by the low temperature of the material. To address this problem, the feeding barrel and nozzle temperatures can be properly increased, or the injection cycle can be prolonged to increase the material temperature. In the meantime, the coolant flow inside the mold should be regulated to properly increase the mold temperature.
    Generally, the strength of the plastic product welding line is relatively low. If the position of the mold with the welding line can be partially heated to partially increase the temperature at the welding position, the strength at the welding line can be enhanced. When a low-temperature injection molding process is used for special needs, injection speed and injection pressure can be increased to improve confluence performance. A small dosage of lubricant can also be added to the raw material formula to increase molten flow performance.
  2. Mold Defect. The fewer numbers of the gate should be adopted, and the position of the gate should be reasonable to avoid inconsistent filling speed and interruption of molten flow. Where possible, a one-point gate should be adopted. To prevent low-temperature molten material from generating a welding mark after being injected into the mold cavity, lower the mold temperature and add more cold water to the mold.
  3. Poor mold venting solution. Check whether the venting slot is blocked by solidified plastic or another substance at first (especially some glass fiber material), and check whether there is a foreign substance at the gate. If there are still carbonation spots after removing the extra blocks, add a venting groove at the flow convergence in the mold or change the gate location. Reduce the mold clamping force and increase venting intervals to speed up the convergence of material flows. In terms of the molding process, reducing material temperature and mold temperature, shortening high-pressure injection time, and decreasing injection pressure can be taken.
  4. Improper use of release agents. In injection molding, usually, a small quantity of release agent is evenly applied at the thread and other positions that are not easy to demold. In principle, the use of the release agent should be reduced as much as possible. In massive production, you should never use a release agent.
  5. The structure of plastic products is not reasonably designed. If the wall of the plastic product is too thin, the thickness differs greatly, or there are too many inserts, it will cause poor welding. When designing a plastic product, it shall be ensured that the thinnest part of the product must be greater than the minimum wall thickness allowed during forming. In addition, reduce the number of inserts and make the wall thickness as uniform as possible.
  6. The welding angle is too small. Each kind of plastic has its own unique welding angle. When two flows of molten plastic converge, the welding mark will appear if the converging angle is smaller than the limit welding angle and will disappear if the converging angle is bigger than the limit welding angle. Usually, the limit welding angle is around 135 degrees.
  7. Other causes. Different degrees of poor welding can be caused by the use of raw materials with excessive moisture and volatile content, oil stains in the mold that are not cleaned up, cold material in the mold cavity or uneven distribution of fiber filler in the molten material, an unreasonable design of the mold cooling system, fast solidification of the melt, a low temperature of the insert, a small nozzle hole, an insufficient plasticizing capacity of the injection machine, or a large pressure loss in the plunger or barrel of the machine.
    To solve these problems, different measures, such as pre-drying of raw materials, regular cleaning of mold, changing the design of mold cooling channels, controlling the flow of cooling water, increasing the temperature of inserts, replacing nozzles with larger apertures, and using injection machines with larger specifications, can be taken in the process of operation.

Issue No. IV: Warp Distortion – What is warp distortion?

Due to internal shrinkage of the product is inconsistent, the internal stress is different and distortion occurs.

Warp Distortion

Warp Distortion

Fault Analysis and Method for Correction

1. The molecular orientation is unbalanced. In order to minimize warp distortion caused by diversification of molecular orientation, create conditions to reduce flow orientation and relax orientation stress. The most effective method is to reduce molten material temperature and mold temperature. When this method is used, it is better to combine it with heat treatment of the plastic parts; otherwise, the effect of reducing molecular orientation diversification is often of short duration. The method of heat treatment is: after demoulding, keep the plastic product at a high temperature for some time and then cool to room temperature gradually. In this way, the orientation stress in the plastic product can be largely eliminated.

2. Improper cooling. When designing a plastic product structure, the cross-section of each position should be consistent. Plastic must be kept in the mold for a sufficient time for cooling and forming. For the design of a mold cooling system, cooling pipelines should be at positions where the temperature is easy to rise and the heat is relatively concentrated. As for the positions that easily cool down, gradual cooling should be adopted to ensure balanced cooling of each position of the product.

Warpage issue

Warpage issue

3. The gating system of mold is not properly designed. When determining the gate position, be aware that the molten material will not directly impact the core, and be sure the stress on both sides of the core is the same. For large flat rectangular plastic parts, a membrane gate or multi-point gate shall be used for resin raw materials with wide molecular orientation and shrinkage, and a side gate shall not be used; for ring parts, a disk gate or wheel gate shall be used, and a side gate or pinpoint gate shall not be used; for housing parts, a straight gate shall be used, and a side gate shall not be used as far as possible.

4. The demolding and venting system is not properly designed. In-mold design, draft angle, position, and the number of ejectors should be reasonably designed to improve mold strength and positioning accuracy. For small and medium-sized molds, anti-warping molds can be designed and made according to their warping behavior. In respect of mold operation, ejection speed or ejection stroke should be properly reduced.

5. Improper operation process. The process parameter shall be adjusted according to the actual situation.

Issue No. V: Sink Mark Defects – What is the sink mark?

Sink marks are unevenly shrinking of the surface caused by the inconsistent wall thickness of the plastic product.

Sink marks

Sink marks

Fault Analysis and Method for Correction

  1. The injection molding condition is not properly controlled. Properly increase injection pressure and speed, increase molten material compression density, prolong injection and pressure-keeping time, compensate for the sinking of the molten, and increase the buffering capacity of injection. However, the pressure should not be too high; otherwise, the convex mark will appear. If sink marks are around the gate, prolonging the pressure keeping time can eliminate the sink marks; if sink marks are at the thick wall, prolonging the cooling time of the plastic product in the mold; if sink marks around the insert are caused by partial shrinkage of molten, the main reason is that the temperature of the insert is too low; try to increase the temperature of the insert to eliminate the sink marks; if sink marks are caused by insufficient material feeding, increase the material. Besides all of this, the plastic product must be fully cooled in the mold.
  2. Mold defects. According to the actual situation, properly enlarge the gate and runner cross-section, and the gate should be in a symmetrical position. The feed inlet should be in the thick wall. If sink marks appear away from the gate, the cause usually is that the flow of molten material is not smooth at some position of the mold, which hampers the transmission of pressure. To solve this problem, enlarge the injection system to allow the runner to extend to the position of the sink marks. For products with thick walls, a wing-type gate is preferred.
  3. Raw materials cannot meet molding requirements. For plastic products with high finish standards, resin with low shrinkage shall be used, or the appropriate dosage of lubricant can also be added to the raw material.
  4. Improper design of product structure. The wall thickness of the product shall be uniform; if the wall thickness differs a lot, the structure parameter of the injection system or the wall thickness shall be adjusted.
  5. sink marks defects

    sink marks defects

Issue No. VI: Flow Mark-What is Flow Mark?

Flow mark is a linear trace on the surface of a molding product that shows the flow direction of molten material.

Flow mark

Flow mark

Fault Analysis and Method for Correction

  1. Ring-shaped flow marks on the surface of the plastic part with the gate as the center are caused by poor flow motion. To address this kind of flow mark, increase the temperature of the mold and nozzle, increase the injection rate and filling speed, prolong the pressure-keeping time, or add a heater at the gate to raise the temperature around the gate. Appropriately expanding the gate and runner area can also work, while the gate and runner section is preferably circular, which can guarantee the best filling. However, if the gate is in the weak area of the plastic part, it will be square. In addition, a large cold-slug well should be set at the bottom of the injection port and at the end of the runner; the greater the influence of material temperature on the flow performance of the melt, the more attention should be paid to the size of the cold-slug well. The cold-slug well must be set at the end of the melt flow direction from the injection port.
  2. Whirl flow marks on the surface of the plastic part are caused by the unsmooth flow of molten material in the runner. When the molten material flows from the runner with a narrow section to the cavity with a larger section or the mold runner is narrow and the finish is poor, the material flow is easy to form turbulence, resulting in a whirl flow mark on the surface of the plastic part. To address this kind of flow mark, reduce injection speed appropriately or control the injection speed in slow-fast-slow mode. The mold gate shall be in the thick wall and preferably in the form of a handle type, a fan type, or a film type. The runner and gate can be enlarged to reduce material flow resistance.
  3. Cloud-like flow marks on the surface of the plastic part are caused by volatile gas. When ABS or other copolymerized resins are used, if the processing temperature is high, the volatile gas produced by the resin and lubricant will form cloud-like ripple marks on the surface of the product. In order to solve this problem, it is necessary to reduce the temperature of the mold and barrel, improve the venting of the mold, reduce the material temperature and filling speed, enlarge the gate section properly, and consider changing the type of lubricant or reducing the use of lubricant.

Issue No. VII: Glass fiber streaks – What is Glass fiber streaks

Surface Appearance: Plastic molding products with glass fiber have various surface defects, such as dim and dreary in color, coarse in texture, and metal bright spots, etc. These are especially obvious in the convex part of the material flow area, close to the joint line where the fluid meets again.

Physical cause

If the injection temperature and the mold temperature are too low, the material containing glass fiber tends to solidify fast on the mold surface, and the glass fiber will not melt in the material again. When two flows meet, the orientation of glass fiber is in the direction of each flow, which will lead to irregular surface texture at the intersection, resulting in the formation of joint seams or flow lines.

This type of defect is more obvious if the molted material is not fully mixed in the barrel. For example, if the stroke of the screw is too long, it will cause the undermixed material to also be injected.

Causes related to process parameters and improvements can be identified:

  1. The injection speed is too low. To increase injection speed, consider using a multi-step injection method like slow-fast mode.
  2. The temperature of the mold is low; increasing the mold temperature could improve the glass fiber streaks.
  3. Molten material temperature is too low; increase barrel temperature and screw back pressure to improve.
  4. The temperature of molten material varies a lot: if the molten material is not fully mixed, increase screw back pressure, reduce screw speed, and use the longer barrel to shorten stroke.

Issue No. VIII: Ejector Marks: What are ejector marks?

Surface Appearance: Stress whitening and stress rising phenomena are found on the side of the product that is facing the nozzle, i.e., where the ejector rod is located on the ejector side of the mold.

Physical cause

If the demoulding force is too high or the surface of the ejector rod is relatively small, the surface pressure here will be very high, causing deformation and eventually whitening at the ejection area.

Causes related to process parameters and improvements can be applied:

  1. Holding pressure is too high; decrease pressure while keeping pressure.
  2. Holding pressure time is too long; shorten holding pressure time.
  3. Holding pressure switch time is too late. advance the pressure-keeping switch
  4. The cooling time is too short; increasing the cooling time

Causes related to mold design and improvements can be applied:

  1. The draft angle is not enough; increase the draft angle according to specification, especially in the area of the ejector mark.
  2. The surface finish is too rough; the mold shall be well polished in the demolding direction.
  3. A vacuum is formed on the ejection side. Install an air valve in the cor

Conclusion

Due to the specific properties of plastics, injection molding is a very complex technological process; unlike the seemingly related process of metal die casting, it is not a mechanical process but a mechanical-physical one. In the injection molding process, a molded piece is obtained. It is characterized not only by a specific shape but also by a specific structure resulting from the flow of the plasticized material in the mold and the course of its solidification.

Because these processes occur in the form of injection, the designer of this tool must take into account, in addition to typically mechanical issues, issues related to the physical nature of the material transformation. Constructing a rationally working form requires, at the same time, from the designer a thorough knowledge of the technical capabilities of the injection molding machine, because it is a machine with extremely rich possibilities provided by its equipment and numerous work programs.

If you want to know more, please go to our other plastic mold page. If you are looking for injection molding services, you are welcome to send us your requirements for a quotation.

If you have a new project or current project that needs a China injection molding company to support you, we are happy to help. Please call us or send us an email.

glass filled PA injection molding

What is Plastic Moulding

Plastic moulding is the plastic work through the Injection moulding machine, The melted plastic will automatically molten after erupting out in all of the plastic moulding methods, injection plastic moulding has been the most widely used. The method comprises the following steps: getting the thermoplastic plastic or the thermosetting plastic imported into the heating cylinder of the injection moulding machine, and when it is completely melted, it will produce heat and frictional heat by the pressure of the plunger or the screw, and is injected into the mould cavity of the closed mould, after curing, and then open the mould and take out the finished product.

Plastic moulding is the principal method of forming thermoplastic materials. Modifications of the plastic injection molding process are sometimes used for thermosetting plastics.

The problem with plastic moulding of thermosetting materials is that, under heat, these plastics will first soften, then harden to an infusible state. Thus it is essential that no softened thermosetting material in the heating chamber be allowed to remain there long enough to set. Jet molding, offset molding and molding using a screw-type machine overcome this problem by liquefying the thermosetting plastic material just as it goes through the injection nozzle into the plastic mold, but not before.

plastic mold technology

Type of plastic molding

There are many type of plastic moulding process, below we will briefly explain each type of plastic mouldings.

Blow Molding

Blow molding is a method of forming hollow articles out of thermoplastic materials.

Blow molding is a process of forming a molten tube of thermoplastic material, then with the use of compressed air, blowing up the tube to conform to the interior of a chilled blow mold. The most common methods are extrusion, injection, and injection-stretch blow molding.

The continuous-extrusion method uses a continuously running extruder with a tuned die head that forms the molten plastic tube. The tube is then pinched between two mold halves. A blow pin or needle is inserted into the tube and compressed air is used to blow up the part to conform to the chilled mold interior. Accumulator-extrusion is similar, however, the molten plastic material is accumulated in a chamber prior to being forced through a die to form the tube.

Injection molding

Injection blow molding is a process of injection molding a preform (similar to a test tube), then taking the tempered preform to a blow mold to be filled with compressed air to conform to the interior of the blow mold. Injection-stretch blow molding can be a single-stage process similar to standard injection blow molding, by adding the element of stretch prior to blow forming. Also, a two-step process is possible, where a preform is made in an injection molding machine, then taken to a reheat-stretch blow molding machine for preform reheating and final blow forming in a blow mold.

Thermoforming molding

plastic moulding

plastic molding company, injection molding machines from 60 Ton to 2000 Ton

Thermoforming of plastic sheet has developed rapidly in recent years. This process consists of heating thermoplastic sheet to a formable plastic state and then applying air and/or mechanical assists to shape it to the contours of a mold.

Air pressure may range from almost zero to several hundred psi. Up to approximately 14 psi (atmospheric pressure), the pressure is obtained by evacuating the space between the sheet and the mold in order to utilize this atmospheric pressure. This range, known as vacuum forming, will give satisfactory reproduction of the mold configuration in the majority of forming applications.

Themoset Transfer Molding

Themoset Transfer molding is most generally used for thermosetting plastics. This method is like compression molding in that the plastic is cured into an infusible state in a mold under heat and pressure. It differs from compression molding in that the plastic is heated to a point of plasticity before it reaches the mold and is forced into a closed mold by means of a hydraulically operated plunger.

Themoset Transfer molding was developed to facilitate the molding of intricate products with small deep holes or numerous metal inserts. The dry mold compound used in compression molding sometimes disturbs the position of the metal inserts and the pins which form the holes. The liquefied plastic material in transfer molding flows around these metal parts without causing them to shift position.

Reaction Injection Molding

Reaction injection molding (RIM) is a relatively new processing technique that has rapidly taken its place alongside more traditional methods. Unlike liquid casting, the two liquid components, polyols and isocyanates, are mixed in a chamber at relatively low temperatures (75° – 140° F) before being injected into a closed mold. An exothermic reaction occurs, and consequently RIM requires far less energy usage than any other injection molding system.

The three major types of polyurethane RIM systems are rigid structural foam, low-modulus elastomers, and high-modulus elastomers.

Reinforced RIM (R-RIM) consists of the addition of such materials as chopped or milled glass fiber to the polyurethane to enhance stiffness and to increase modulus, thus expanding the range of applications.

Compression Molding

Compression molding is the most common method of forming thermosetting materials. It is not generally used for thermoplastics.

Compression molding is simply the squeezing of a material into a desired shape by application of heat and pressure to the material in a mold.

Plastic molding powder, mixed with such materials or fillers as woodflour and cellulose to strengthen or give other added qualities to the finished product, is put directly into the open mold cavity. The mold is then closed, pressing down on the plastic and causing it to flow throughout the mold. It is while the heated mold is closed that the thermosetting material undergoes a chemical change which permanently hardens it into the shape of the mold. The three compression molding factors — pressure, temperature and time the mold is closed — vary with the design of the finished article and the material being molded.

Extrusion Molding

Extrusion molding is the method employed to form thermoplastic materials into continuous sheeting, film, tubes, rods, profile shapes, and filaments, and to coat wire, cable and cord.

In extrusion, dry plastic material is first loaded into a hopper, then fed into a long heating chamber through which it is moved by the action of a continuously revolving screw. At the end of the heating chamber the molten plastic is forced out through a small opening or die with the shape desired in the finished product. As the plastic extrusion comes from the die, it is fed onto a conveyor belt where it is cooled, most frequently by blowers or by immersion in water.

In the case of wire and cable coating, the thermoplastic is extruded around a continuing length of wire or cable which, like the plastic, passes through the extruder die. The coated wire is wound on drums after cooling.

In the production of wide film or sheeting, the plastic is extruded in the form of a tube. This tube may be split as it comes from the die and then stretched and thinned to the dimensions desired in the finished film.

In a different process, the extruded tubing is inflated as it comes from the die, the degree of inflation of the tubing regulating the thickness of the final film.

plastic injection mold tooling

Plastic Moulding Knowledge Guidance

1 The basic knowledge of plastic molding.
1.1 The characteristics and composition of plastic injection moulding.

Plastic Injection moulding is to fill the molten moulding material in a closed mould with high pressure. The pressure that the plastic molding cavity needs to be subjected to about 400 KGF / CM2, approximately 400 atmospheres. With such a high pressure to make a product is its characteristic which is not the only an advantage but also disadvantages. In other words, the mold always has to be made stable, therefore its’ price is always high. So must be mass-produced in order to buckle with high-priced mould costs. For example, the production of each batch must be more than 10000PCS to be reasonable. In other words, plastic molding work surely has to be a mass-production.

A few steps of the plastic molding process :
1.1.1 Closing
Close the security and then start moulding
1.1.2 Clamping mold
Moving forward the moving board in order to get the mould closed. When the mould is closed which means is also locked.

1.1.3 Injecting (including holding press)
The screw is quickly pushing forward, injecting the molten formed plastic material into the mould cavity to full fill it. Keeping the press at the same time after full filling it, this action is particularly named “holding press.” The pressing that the mold has to bear when it just gets full filled, generally called ‘Injection Press’ or ‘one press’.

1.1.4 Cooling off (and the next step of the plasticization project)

The process of waiting for the material getting cool formed in the mould cavity is called “cooling off”, At this time the injection device is also ready for the next step, this process is called “plasticization process. The moulded material is placed in the hopper, inflow into the heated tube to heat, it is based on the rotation of the screw turning the raw material into the molten status.

1.1.5 Opening the mould

Move the moving board to the backward and the mould will be opened.

1.1.6 Opening the security door

Opening the security door, then the machine will be in the standby status.

1.1.7 Picking up

Taking out the product, checking carefully if there is anything left in the mould cavity, and this whole forming operation is called moulding cycle time. The finished product is shaped by the shape of the mould. The mold is composed of the left mould and the right mould, These two sides of moulds are left with voids, and the material would flow into the voids and get compressed to finish the product. There are three main lines of the path of the molding material before it flows into the left side and right side, sprue, runner, gate, and so on.

1.2 Injection molding machine

Injection moulding machine is distinguished from two large projects, they are divided into two, clamping device and injection device.

1.2.2 clamping device

Closing the mould, the molding material would be cooled off and solidified in the mould cavity. Opening the mould cavity and take out the finished product is the action of the clamping device

1.2.3 Injection Device

Injecting the plastic material into the mould cavity called ‘Injection device’

The following describes the ability of the injection moulding machine, there are three provisions to distinguish the ability of it.

A. Clamping force

When the injection is made, the mould won’t be opened by the maximum clamping force, expressed as the number of TON.

B. Injection volume

The weight of a shot is generally expressed in terms of grams.

C. Plasticizing capacity

A certain amount of time able to melt the amount of resin, this is generally expressed in terms of grams. The most important part is the clamping force, the area of the moulded article is referring the mould perpendicular to the shadow of the opening and closing direction (basically the moud’s area). The average pressure within the mold added to the projection area is called the clamping force. If the mold “projection area × average pressure” is greater than the “clamping force” then the left and the right side moulds will be pushed out.

Clamping force = projection area × average pressure within the mold In general, the mold can withstand the pressure of 400KGF / Cm2, so base on this figure to calculate the clamping force, but the clamping force often based on the shape of forming materials and the shape of the product’s vary, the difference between the larger parameters such as PE, PP, PS, ABS materials, these raw materials are used to make the shallow box, the parameter is 300KGF / CM2.

If the depth of the box is deeper then the parameter is 400 KGF / CM2, If it is the small but high precision products. The projection area is about 10CM2 or less, its parameters are 600KGF / CM2. The smaller parameters such as PVC, PC, POM, AS materials, these materials are also used to make a shallow box, the parameters of 400KGF / CM2, if it is a deep box of its parameters is 500KGF / CM2, if it is a small and high precision products, projection area of about 10CM2 below, its parameter is 800KGF / CM2.

To working with Plastic Moulding is not easy, if you have a project that needs plastic molding service you need to find a professional plastic molding company to support you, to reduce your plastic mold and Injection moulding cost, find a Chinese molding company to support you will be one of the best options, plastic mould and moulding parts from China mold company has inexpensive price and short lead time, this is no reason that you do not choose your plastic molding supplier from China, on the world, over 80% or overseas companies that buy products from China, China is the biggest manufacturer country on the world, this is no doubt about this,

Plastic box mold

We are A Plastic Molding Parts Manufacturing Company

Finding the right source for all your injection molded thermoplastic parts is as easy as selecting DONGGUAN SINCERE TECH CO.LTD (SINCER ETECH). If you need quality injected-molded parts from an ISO 9001:2000 Certified supplier, and you need them on time, ACM is the answer.

Plastic Mold & Plastic Molding Parts Service: Your One-Stop Solution

Sincere Tech is a top 10 injection mold companies in China, offer injection mould, plastic moulding service to the world, 90% of our mold and parts are export to American, Europe, and the world, SINCERE TECH is a “one-stop, one-responsibility” company. our skilled, quality-minded thermoplastics professionals are committed to superior service, providing solutions to customers’ needs from concept to finished product. At our modern plastic molding facility you will be guaranteed:

  • Top quality products
  • The latest in technological equipment
  • Cost-effective manufacturing processes
  • Quality assurance procedures

We are capable of producing a wide variety of plastic parts and components, for industries of all types, including:

  • A / C Vents
  • Actuators
  • Bezels
  • Blood Testers
  • Boat Parts
  • Bobbins
  • Bottle Ties
  • Boxes
  • Brackets
  • Buckles
  • Cases
  • Clips
  • Component Boxes
  • Computer Peripherals
  • Connectors
  • Cosmetic Packaging
  • DVD / VCR Faceplates
  • Faucet Extrusions
  • Flower Pot Bases
  • Fuse Blocks
  • Gear Shift
  • Knobs
  • Gears
  • Housings
  • Junction Boxes
  • Key Fobs
  • Knobs
  • Lenses
  • Light Pipes
  • Motor Housings
  • Name Plates
  • Phone Parts
  • Push Buttons
  • Radiator Tops
  • Seat Belt Parts
  • Shields
  • Spacers
  • Spools
  • Switches
  • Tail Lamp Sockets
  • Toys
  • Trim Plates
  • Typewriter Parts
  • Vents
  • Vials
  • Wedges
  • Window Lift Parts
  • Wire Shields

SINCERE TECH’s Capabilitiesplastic mold manufacturing company

SINCERE TECH’s molding machines range from 60-ton to 2000-ton. We are equipped to mold products from many varieties and grades of resin, each with different properties, including:

  • Thermoplastic commodity resins
  • Engineering grade resins (filled and unfilled)
  • Elastomeric materials

Read more details about our Production Facility and Equipment.

Additionally, our facilities can provide a number of secondary operations, such as:

  • Assembly
  • Pad Printing
  • Painting
  • Drilling
  • Ultrasonic Welding
  • Milling
  • Ultrasonic Insertion

Read more details about our Production Facility and Equipment.

You are welcome to send us your new project, we will quote you with 24 hours, we will offer you the best solution for your new project to save you price, not only the injection molding process, but rubber molding, metal parts etc.

 

product design and manufacturing

Plastic Product Design Service from plasticmold.net

Plastic product design service according to your sketch or samples, Change Draft Directions, Initial Design Consultation, Improve Efficiency, Change Draft Directions, Eliminate Undercut, Eliminate Sink Marks

SINCERE TECH can produce a plastic product design from your concept, sketch, samples or modify your product designs for required changes on most plastic parts.

SINCERE TECH, one of the most trusted top 10 plastic injection molding companies in China that offers mold design, injection molding service, injection mold making, and engineering, will consult on the initial design, or design enhancements to help improve efficiency in the  manufacturing process, including:Plastic Product Design

  • Changing draft directions
  • Design concessions for radii and step-throughs
  • Undercut elimination
  • Coring to eliminate sink marks

All the above design improvement has no cost

Perfect Plastic Product Design will make High-Quality Molds, high-efficiency molding production, cost saving on both molds and molded parts

Craftsmen at SINCERE TECH are capable of constructing intricate and efficient molds quickly, whether they be simple single-cavity mold or complex multiple cavity mold. All SINCERE TECH molds are designed to use high-quality mold bases and mold steels; and are engineered for maximum process windows, ease of repair and long life.

We have a wide range of manual, automatic and computerized mold making equipment to accomplish our goal, including:

  • Mills
  • Grinders
  • EDM Machines
  • Drills
  • Lathes
  • Saws
  • CNC Machining
  • CNC Programming
  • Design equipment and software
  • Inspection and Measurement
  • Polishing Tools

Our plastic mold makers are fully qualified and skilled at using modern production techniques. Using our computerized CNC (Computer Numeric Coordinates) System (CAD/CAM), SINCERE TECH team are able to produce new custom molds with cost-saving speed and accuracy or troubleshoot your existing molds.

Whether the job calls for conventional, hot, or insulated runner systems, SINCERE TECH toolmakers have the experience to design and build the mold correctly.

Advanced Plastic mold making technology allows us to design and produce molds for a wide variety of plastic part applications,

If you have your plastic prodcut design ready and look for plastic mold making service, you are welcome to send us your design, we will offer you the best price. If you only have samples or sketch, you are welcome to contact us as well, we will make plastic product design, mold making, injection molded parts for you by the best solutions,

We never share your data with any other third parties, we can sign NDA document to protect your project,

OEM plastic injection molding parts supplier

What is Plastic injection moulding machine

Plastic Injection Moulding Machine is the most important machine in your business if you are planning to have plastic injection moulding method in manufacturing your plastic products. Through this machine, your company could manufacture a lot of different types of plastic products in 2D and 3D. With the help of plastic injection moulding machine, a lot of different plastic products could be produced from your company.

Surely, the quality of your plastic injection moulding machine will be determining the quality of the molded plastic products produced by your company. Therefore, choosing the best machine to support your business is something important to be taken. Great quality of plastic injection moulding machine will produce high quality of plastic product with strong and great durability. So, do not take the wrong choice.

There are several different types of plastic injection moulding for machine that could support your business well. You can contact some distributors to order a certain product for your company. Or you can also get your selected plastic injection moulding machine through some reliable online stores. However, what you need to do first is looking for more information to get the best selection.

Are you interested to have plastic injection moulding machine in your plastic business company? If so, this following review will be very helpful to give you references about some products that will support your business well. Read the information well and get the best machine for plastic injection moulding that meets the requirements of your company well.plastic Injection Moulding Machines

China Plastic Injection Moulding Machine

As the first option, you can take a look at China Plastic Injection Moulding Machine. This product works great in providing great support to your plastic business company because it offers high efficiency of time. This machine will be very helpful to produce great quantity in faster time.

Therefore, you can save more time to produce bigger quality of products. You can find this machine easily in some online stores. Since this product works in great quality of performance, you can always get total satisfaction with this certain machine for plastic injection moulding as an important part in your company.

SZ-700A Plastic Injection Moulding Machine

Then, you can also get SZ-700A Plastic Injection Moulding Machine. This product will be perfect to be chosen since it is specifically designed in high performance. It is completed with 60-10000 grams of injecting capacity as well as 60-1600 tons of clamping force to bring more supports for your business.

There will be many more advantages offered by this machine for plastic injection moulding. Stable movement curve and gentle shock are just a little advantage offered by this certain product. To easier the operator in controlling this machine, SZ-700A Plastic Injection Moulding Machine is also completed with LCD computer control. It will be great product to be chosen.

50T Automatic Plastic Injection Moulding Machine

Then, you can also get 50T Automatic Plastic Injection Moulding Machine as the next machine to support your business. This product is completed with LCD computer control to easier you set and operating the machine. This product will be perfect to provide injection molding for various thermoplastics such as PC, PP, PE, Nylon, PVC, ABS, PET and many more. By providing this machine, you can produce many types of medium or small size plastic products as well as daily-use commodities.

Related Info to Plastic Injection Moulding Machine

Certainly! Plastic injection molding machines are used in the manufacturing process to produce plastic parts through the injection molding process. Here is some related information about plastic injection molding machines:

  1. Basic Operation:
    • Plastic injection molding machines melt plastic granules and inject them into a mold to create a specific shape.
    • The process involves heating the plastic material, injecting it into the mold, cooling it, and then ejecting the finished product.
  2. Key Components:
    • Injection Unit: It melts and injects the plastic into the mold.
    • Clamping Unit: It holds the mold in place during injection and cooling.
    • Hydraulic System: Provides the power for the machine’s movements.
    • Control System: Manages and monitors the machine’s operation.
  3. Types of Plastic Injection Molding Machines:
    • Hydraulic Injection Molding Machines: Use hydraulic power to operate the machine.
    • Electric Injection Molding Machines: Use electric motors for machine movements, offering energy efficiency and precision.
    • Hybrid Injection Molding Machines: Combine hydraulic and electric systems for improved efficiency.
  4. Mold Design:
    • The mold is a critical component and determines the final product’s shape.
    • It consists of two halves, the cavity and the core, which form the desired shape when closed.
  5. Materials Used:
    • Common materials processed include thermoplastics, thermosetting polymers, and elastomers.
    • Material selection depends on the application, required properties, and production volume.
  6. Applications:
    • Injection molding is widely used across various industries for producing components such as automotive parts, consumer goods, medical devices, and packaging.
  7. Quality Control:
    • Continuous monitoring of the injection molding process is essential for maintaining product quality.
    • Parameters such as temperature, pressure, and cooling time are closely controlled.
  8. Advancements:
    • Industry 4.0 technologies are being integrated into injection molding machines for improved automation, monitoring, and data analysis.
    • Sustainable practices, such as using recycled materials and energy-efficient machines, are gaining importance.
  9. Maintenance:
    • Regular maintenance is crucial to ensure the machine’s optimal performance and longevity.
    • Components like screws, barrels, and heaters need periodic checks and replacements.
  10. Safety Considerations:
    • Injection molding machines pose potential hazards, and safety measures such as machine guarding and operator training are essential.

Understanding these aspects provides a foundation for those involved in the plastic injection molding industry, from machine operators to design engineers and manufacturers.

Plastic Injection Molding or Plastic Injection Moulding

Plastic injection moulding is a method utilized to produce parts of thermosetting with thermoplastic materials. In this process, the raw material is fed into a …

Custom Injection Molding

Custom injection molding will be perfect method to make greater plastic part production in higher efficiency. With the versatility offered by this certain method, you …

Injection Moulding

Injection moulding is a certain industrial term that refers to a technique in producing plastic accessories or stuffs. This method now is quite popular …

If you are looking for mould suppliers offer you plastic injection molding service, welcome to contact us.

 

high volume plastic injection molding

Custom Plastic Molding

Custom Plastic molding is one of the most cost-effective processes for producing large quantities of plastic products. It uses a die or mold in which melted plastic is injected under pressure, cooled, and hardened to produce the final part before being released. This cycle can be repeated very quickly, possibly 1000 times, which distributes the initial cost of the mold over a large number of units, making the cost per part a few dollars or less.

Repeatability and reliability are achieved because a single mold can be used to produce each part. Furthermore, injection molding provides flexibility in terms of a broad range of material options, colors, finishes, and surface treatments that cannot be matched by CNC machining or 3D printing.

Sincere Tech has a highly skilled workforce with years of experience in different sectors, like medical injection molding and LSR molding. New customers are also given a $500 credit on their first mold with Sincere Tech. We have choices for domestic and custom plastic molding company services from a broader prospect.

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Types of Custom Plastic Molding Techniques

In designing custom molded products and their components, it is critical to choose the correct manufacturing process to obtain a high-quality and durable final plastic product with acceptable costs and production time. Here are the most commonly used techniques of custom plastic molding process;

Thermoforming

Thermoforming involves heating a large sheet of plastic to make it pliable and then forming it over a one-sided mold. The use of vacuum pressure or compressed air to force the thermoplastic closely against the mold to the required shape. The advantages of thermoforming are the low cost of tooling, the short time to market, and the ability to produce large parts such as bathtubs and car dashboards. Also, thermoforming is fast in prototyping and can be customized to a great extent.

Extrusion molding

Extrusion molding is mainly applied to produce long and straight products such as tubes, hoses, or pipes. This method involves the use of pressure to force liquid plastic into a specific shape of a die. Although round shapes are typical, t-shapes, l-shapes, and squares are also possible due to the die’s shape. The advantages of extrusion molding are the low cost of tooling and machinery, little or no need for finishing other than cutting the pieces to the required length, and the possibility of attaining intricate and uniform cross-sectional shapes.

Compression molding

Compression molding is most commonly applied with thermosetting plastics, which, when heated and then cooled, undergo a chemical change to become a rigid solid. In this method, the plastic resin is melted and formed into a putty-like substance and then put into a hot mold. The putty is then compacted by the mold and left to cool. Compression molding is suitable for making plastics that compete with metals, are suitable for rigid lightweight thermosets, and are commonly used in fiberglass reinforced or rubberized plastics.

Blow molding

Blow molding is similar to injection molding, where the plastic is first melted and then injected into the mold. Air is then pumped into the plastic, making it expand and conform to the shape of the mold walls. Blow molding is most suitable for manufacturing items that are thin-walled and have a hollow structure, like water bottles or 2-liter bottles for sodas. This method is fast and is relatively cheaper when large quantities are being produced.

Rotational molding

Rotational molding, or “roto-molding,” is the process of placing a mold into a heated container of liquid polymer and then spinning the mold rapidly. This process covers the plastic uniformly on the walls of the heated metal mold while the interior remains empty. Rotational molding is mainly applied to large, hollow-partitioned containers, storage bins, and even kayaks. The advantages of this method include low setup costs, constant thickness of the walls, and low cost for very small or short runs.

Injection molding

Injection molding is one of the best cost-effective molding technology comparing to rest of above, and this is our mean services, we have offering this service over 18 years, if you have any project that need custom injection molding service, welcome to contact us, and you can go to custom injection molding page to know more about this technology.

The six manufacturing methods of plastics are as follows: By knowing these six manufacturing methods of plastics it will assist manufacturing companies in choosing the best method that will produce the required durability, quality, cost, and efficiency of the products.

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Custom Molding Plastic Materials

Custom plastic mold uses engineered grade custom molded plastics to design intricate patterns or part designs. Some common types include;

ABS, or acrylonitrile butadiene styrene, is a strong plastic that is used in many market goods. A lot of people know this material for how well it resists wear and shock. It is often found in car parts and home items.

ASA stands for acrylonitrile styrene acrylate. It is like ABS, but it is more resistant to UV light, so it can be used outside. It doesn’t fade or wear out quickly. This material is often used in cars and outdoor furniture.

Calcinedioacetate, or CA, is a clear material that can be bent and is used in films and glasses. For uses that come into touch with food, it is safe. It looks shiny and can hold its shape well when pulled apart.

HDPE, which stands for “high-density polyethylene,” is strong for its weight and doesn’t react with chemicals. It’s used for many things, like fuel tanks, food bins, and playground equipment outside. Strong and resistant to the weather.

It has a great mechanical strength even at high temperatures. It is called LCP (liquid crystal polymer). Micromolding and parts with thin walls are both possible. It is used in medical products and electrical connectors.

LDPE, or low-density polyethylene, is a strong material that can be used for many things and doesn’t react with acids, bases, or alcohol. Used in snap lids, trays, and other general-purpose cases. Offers good resistance to force.

PA 6 (polyamide 6, nylon 6) is known for being stiff and strong on a technical level. It resists heat and chemicals well. Used in industry and automotive parts.

PA 6/6, also known as polyamide 6/6 or nylon 6/6, is similar to PA 6 but has better mechanical qualities. Better at keeping heat in. Used a lot in places where there is a lot of stress, like gears and bearings.

Polyarylamide, or PARA, is often backed with glass or mineral fibers to make it hard. You can use it to make structural parts because it doesn’t creep or soak up water. Used for medical and travel purposes.

Polybutylene terephthalate, or PBT, is a type of plastic made from polyester that is used to keep electronics safe. Often used as an alternative to nylon in car parts because it doesn’t wear down as quickly. Offers good stability in terms of size.

Polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) are two materials that work well together to make things stronger and more resistant to chemicals. Used in situations where the ability will be needed for a long time. Seen in the production of car and electronic parts.

PC, or polycarbonate, is a type of polymer that is very light and doesn’t break easily when hit. It is often used in safety gear and glasses. This item has great sharpness and lasts a very long time. Widely used in many fields for tasks that need to be very strong.

PC-ABS, which stands for polycarbonate-acrylonitrile butadiene styrene, is a mix of PC, which is stiff, and ABS, which is flexible. Strong enough for technical tasks that need to be done. Used in the electronics and auto businesses.

PC-PBT (polycarbonate-polybutylene terephthalate, Xenoy): Can’t be damaged by chemicals or lubricants used in the housing of electronics. Offers strength and stiffness. Often used in industrial settings.

PC-PET, which stands for polycarbonate-polyethylene terephthalate, is a material that is strong and resistant to poisons. Strong cleaners and chemicals won’t work on it. utilised in the creation of sporting items and medical gear.

Polycyclohexylenedimethylene terephthalate (PCT): It absorbs water better and is more stable in the environment than PET. It is often used in switches and links. Suitable for applications that need great performance.

PE (polyethylene): It can be shaped very easily and is resistant to chemicals and wear. Used in tubes, films, bottles, and other packaging products. It has different grades, like UHMW, LDPE, and HDPE.

PEEK, which stands for polyether ether ketone, is very strong when pulled apart and doesn’t melt at high temperatures. In high-stress situations, it is sometimes used instead of metal. It is used in medical and aircraft settings.

Polyetherimide, or PEI, is used a lot because it can handle high temperatures and flames. A cheap material that can be used instead of PEEK in medical settings. Offers good stability in terms of size.

Polyethylene-polypropylene, or PE-PP, is a blend made up of polyethylene and polypropylene that has properties of both. Used in a variety of general-purpose situations. Chemical protection is good.

Polyethylene-polystyrene (PE-PS) is a material that has the qualities of both polyethylene and polystyrene. Suitable for a wide range of uses. combines being flexible and stiff.

Plastic called polyethersulfone (PES) is clear, hard, and doesn’t mix with chemicals or heat. It can also be sterilized. Used in the aerospace and food processing equipment businesses. It is often used in situations where great performance is needed in harsh conditions.

PET (polyethylene terephthalate, Rynite): It’s usually tough, clear, and light, and it’s used to make food wrappers and drink bottles. With a plastic code of 1, it can be recycled. It works well as a shield.

PLA, or polylactic acid, is a plastic that is good for the climate, can be recycled, and has a low glass transition temperature. Often used in short-term situations. Compostable and good for the environment.

PMMA, also known as acrylic or polymethyl methacrylate, is a clear plastic that looks like glass and wears well. Great for using outside. For example, in displays, signs, and glass.

Acetal polyoxymethylene, or POM, is a material that doesn’t absorb water and doesn’t stick to things easily. A great choice for precise parts. Used in bearings, gears, and other industrial parts.

Polypropylene (PP): It’s good at conducting electricity and staying stable in chemicals. Low ability to absorb water. It is used in textiles, car parts, and packaging.

Polyphthalamide, or PPA, is a type of nylon that has a relatively higher melting point and a relatively lower ability to absorb water. It can be used in both cars and factories. Useful for devices that distribute fuel and fluids.

Polyphenylene sulphide, or PPS, is a high-tech thermoplastic that is very resistant to acids. Found in the electronics and auto businesses. It’s very resistant to heat.

PS (polystyrene) is clear, stiff, and easy to break. It is often used to make food wrap and single-use items. It doesn’t cost much and is easy to make. Often found in shopping goods.

Noryl is made of PS-PPE, which is polystyrene-polyphenyl ether. It is also very resistant to heat and flame. Good hardness and tensile strength at high temperatures. Used in the auto and electrical businesses.

Polysulfone (PSU) is stylish, hard, and clear. It’s a better choice than polycarbonate and works better. Used in the production of medical gear and tools for moving food. Chemical protection is good.

Polyvinyl chloride (Shore D) or PVC is a hard, mass-produced plastic that is used to make pipes and things that don’t last long, like food wrap. Long-lasting and useful. Used in the automotive and building industries.

PVDF (polyvinylidene fluoride, also known as Kynar): Doesn’t mix with anything and can handle high temperatures. Used to make plumbing parts, electrical insulation, and chemicals. It doesn’t stick to things well and doesn’t last long.

SAN stands for styrene acrylonitrile. It is clear, doesn’t melt in the heat, and is cheap. Kitchen tools, plates, and other things used around the house have it. It makes the gloss and clarity better.

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Elastomeric Injection Molded Materials

Elastomeric parts can also be processed through the injection molding process, transfer molding, and compression molding. Some common types include;

EPDM (ethylene propylene diene monomer rubber): EPDM is widely used due to its high heat and chemical resistance. Some common uses include in automotive seals, gaskets, O-rings, and electrical insulators.

PEBA (polyether block amide): PEBA is soft and flexible and widely used in the construction of medical instruments such as catheters. PEBA foams are used for padding, shoe insoles, and sports equipment because of their moisture and UV resistance.

PVC (polyvinyl chloride, Shore A): PVC is an elastic thermoset that is a resilient material, and is often used in products for outdoor use, protective coatings, and mats. It needs plasticizers to make it flexible and is famous for its flame resistance.

TPE (thermoplastic elastomer): TPEs are a group of elastomers that possess the characteristics of thermosets but with the processing ability of thermoplastics. They encompass a broad spectrum of special elastomer categories.

LSR (liquid silicone rubber): These are used in foods and biomedical applications due to their heat, biocompatibility, and flexibility. LSR is applied in medical devices, automotive, aerospace, and consumer products, and it is processed differently from injection molding.

Custom Plastic Molding Surface Finishing Options

Standard Finish: This finish, usually SPI B-2, is selected by the mold maker depending on the part’s shape and the angles of the parting line. It is often applied to non-aesthetic parts, and the parts are left machined for functionality without extra expense or time.

SPI Finishes: These are the standard surface finishes set by the Society of the Plastics Industry that dictate the feel and look of the molded parts. They assist in meeting certain aesthetic and functional objectives, which makes them suitable for many uses.

MoldTech Finishes: These are specialized texturing processes that put patterns or textures on the mold surface to improve the aesthetic and feel of the finished part. MoldTech finishes are applied to achieve specific looks and enhanced tactile feel or to mimic other materials such as wood or leather.

Other Textures – VDI: VDI textures are available in various forms, with varying degrees of roughness and appearance to meet certain design requirements. They are widely applied in industries where the surface finish is a critical factor in the product’s functionality or aesthetics.

Design Tips For Custom Plastic Molding

Undercuts: Reduce undercuts to make the tool ejection mechanisms easier and to avoid complications in manufacturing. The use of pass-through coring can also help achieve this goal while at the same time not compromising on the costs of production.

Wall Thickness: Ensure that the thickness of the wall is constant so that there will not be problems such as wall sinks and voids during molding. Reduced wall thickness is beneficial in the aspect of cycle time and cost of manufacturing.

Drafts: Make sure that the parts have a minimum draft angle of 0. 5° to 5° especially when molding textured faces, to ensure that the faces eject smoothly and free from molding defects.

Ribs/Gussets: Make the ribs to be 40-60% of the outer wall thickness while ensuring that the draft angles are correct for the structure. In this case, it is possible to achieve an increase in strength while maintaining the moldability of the gussets.

Bosses: Design bosses with a depth of 30% of the thickness of the wall and include a 30% edge recess for optimal performance.

Benefits & Applications of Custom Plastic Molding

Injection Molded Part: The tooling is inexpensive, and the company can produce parts quickly, with delivery in as little as 10 business days at low prices.

Rapid Prototyping: Injection molding is a fast method of prototyping and can be used to test various designs within a short span.

Production Parts: Custom plastic molds are ideal for manufacturing a large number of production parts at high efficiency and low cost.

Range of Industries and Certifications: Injection molding is used in different fields and complies with the necessary standards to meet the needs of specific applications.

Stand Afirm With Sincere Tech For Your Custom Plastic Molding Project

In as much as custom plastic injection molding is concerned, Sincere Tech is one of top 10 plastic injection molding compnies in China. With ISO 9001:We have 2015 and ISO 13485 certifications, and this means that we value quality and precision in all the projects that we undertake. The extensive capabilities make it possible for us to work with many industries and provide high-quality injection-molded components with high precision.

Contact us today to find out more about our state-of-the-art plastic injection molding services. Whether it is prototype or production parts, Sincere Tech is dedicated to providing you with the parts you need in the best quality by offering stringent quality custom molded plastic materials and finishing solutions. So, do not wait to get a quote and become our partner in your next successful injection molding project.