Insert mold, Insert molding, overmolding

Overmolding Insert Molding

In the plastics industry, injection molding is a significant process that is used to produce a large volume of plastic parts or products. This technique involves the use of a mold, usually of steel-made metal, that has an interior pattern that resembles the intended design of the part or product. The material, usually inserted after melting into a liquified or molten hot plastic state, is forced into a die cavity, eventually cooled, and then released to create thousands of similar pieces by applying high pressure.

Due to high production accuracy, almost all large-scale plastic products on the market today are fabricated through injection molding techniques. The process has many benefits, such as low cost per part production, short time per part manufacturing, accommodating several materials, and high accuracy of the final part meeting exact tolerance requirements.

These include overmolding vs. insert molding techniques. Although both are interchangeably used, there are clear distinctions between them. This blog post specifically provides key details about two techniques: overmold vs. insert mold processes, by highlighting their differences, applications, and situations to choose between the two.

Insert Molding: How Does It Work?

Both overmolding and insert molding techniques involve injection molding. In the process, metal parts are placed into a mold cavity, and then plastic is injected. These metal inserts are placed in the mold by hand or with the help of industrial robots used in automated processes. Once the mold is in position, the mold is closed, and a plastic material is injected over the metal inserts to create a single, unbroken part.

These features enable easy assembling and disassembling of the parts without any effect on the quality or appearance. For instance, heat-set threaded inserts are used in the plastic parts to reduce the likelihood of thread damage during assembly.

In addition, insert molding may sometimes even reduce the need for secondary fasteners. This technique involves the direct incorporation of required metal components into the mold to form a strong, single component that increases the mechanical stability of the part and minimizes the chances of part breakage. If you want to know more about insert molding, please go to what is insert molding page.

Why should one opt for Insert Molding?

Insert molding is an adaptive manufacturing process to produce high-strength plastic components. Let’s discuss its extensive use cases:

Reduced Assembly Costs: An injection molding machine is capable of producing thousands of parts in a minimal time frame, and this makes it economical for large batch parts production. In contrast to CNC machining, sheet metal fabrication, or 3D additive manufacturing techniques, where the assembly can become a significant problem, insert molding can minimize or even remove the need for additional assembly and tooling requirements, which will lead to further cost optimization of projects.

Enhanced Part Performance: Plastic parts are typically not as durable as their metal counterparts, but plastic has its benefits, including being cheaper, easier to mold into different shapes, and lighter in weight. Insert-molded products normally entail durability due to the combination of plastic (a substrate on which metal is inserted) and metals (insert both materials). This ensures that the intended part being inserted has the necessary strength and stiffness. Moreover, the plastic matrix helps reduce the overall weight of parts. Furthermore, insert molding imparts in parts the ability to resist cyclical loads and other loads.

Disadvantages of Insert Molding

Despite its several benefits, insert molding also comes with certain limits that product manufacturers must consider: These common drawbacks include;

Multiple Manufacturing Technologies: Insert molding may need to be done in two phases in general. Metal-forming processes such as CNC machining may be used when manufacturing custom-designed inserts rather than off-the-shelf parts. These methods are generally costlier per part than fully injection-molded processes. While it is possible to reduce the cost of manufacturing metal inserts by employing techniques such as metal die casting or metal injection molding (MIM), Despite this, the cost of manufacturing parts with metal inserts is still higher than that of parts made entirely out of plastic.

Increased Part Complexity: When producing products that have to have metal inserts made to order, it’s essential to have a deep understanding of both metal and plastic manufacturing. Product designers must know the DFM rules of both technologies and how to combine them into one part that functions as required. This can add to the design and manufacturing time and cost of the product.

An Overview of the Overmolding Process?

Overmolding is a subcategory of insert molding, which is the process of molding one plastic material directly onto a formed part. In this process, the first part is molded by injection molding, and then it is placed in the second mold for the overmolded material. This technique enables the use of two or more plastics in the production of a single product, giving the product both utility and beauty.

For example, overmolding allows for the combination of different Shore hardnesses, providing a soft touch layer on top of a rigid base for better grip and feel. Also, the use of multiple colors in an overmolded part can give it a competitive edge since it is not easily seen in other products. This technique is widely applied to the grips of tools like screwdrivers, power drills, and toothbrushes since both the comfort of the grip and the product’s appearance are essential factors.

Why choose the overmolding process?

Overmolding offers a range of benefits that make it a versatile and advantageous process.

Increased Material Flexibility: Overmolding enables the use of different materials in a single part, and this makes it possible to have different properties in the same part. This process improves the product’s looks, feel, and usability, which is advantageous to both the product and the consumer.

Elimination of Adhesives: Overmolding is a process where two or more different materials are joined together through an injection mold, thus replacing the need for adhesives or other joining techniques. This not only strengthens the final part but also cuts the assembly costs.

Integrated Seals: Overmolding makes it possible to bond soft seals directly onto molded parts. For instance, in electronics enclosures with IP ratings, an overmolded seal is cheaper and more efficient than fitting an o-ring groove. This integration enhances the performance of the part and the structural stability of the whole system.

Limitations of overmolding

Overmolding, despite its numerous benefits, comes with certain drawbacks:

Complex Process: Overmolding is a two-shot process, which means that the part cycle time and the cost are higher than in single-part molding. Also, it calls for the application of two tools or a two-shot mold that is quite expensive to produce. However, these are some of the challenges that one can face when using overmolding, but it can be cheaper than manufacturing two different injection-molded parts and then joining them.

Debonding Risk: The problem of delamination or distortion may occur when two different materials are bonded in an injection mold because the temperatures may not be ideal for the given material combination. This may require the use of mechanical interlocks in order to achieve a secure connection where heat alone is not enough.

If you want to know more about overmolding, please go to the overmolding page to check this out.

Industrial Uses of Overmolding vs Insert Molding

Both overmolding and insert molding are widely used for applications requiring high-quality and stringent products. Nevertheless, all these techniques have similar uses, and they are employed to manufacture numerous parts and products.

Automotive Industry

Both insert molding and overmolding play a vital role in manufacturing numerous automotive parts that contain metal, rubber, or plastic, such as batteries, knobs, dash panels, motors, and handles.

Cosmetic Industry

These techniques are indispensable in the cosmetics industry for producing custom-made items and their containers with the use of various colors and surface treatments of cosmetic items such as perfume flacons, cosmetic brushes, and compacts.

Consumer Products

In the case of household products, insert mold and overmold play a central role in manufacturing items such as toothbrush holders, containers, and cell phone cases. They also reinforce items such as patio chairs and step stools, which are usually found in multiple colors or materials.

Electrical Appliances:

The use of insert molding cannot be overemphasized, particularly in the electrical industry, where wires are coated with rubber insulation. This process helps to stop electrical conduction and increase safety levels. Insert molding also makes electrical appliances safer to handle by providing a proper place for insulators to be installed.

Sincere Tech is one of the top 10 plastic injection molding companies in China that specializes in creating unique products for different sector., With the help of the technical knowledge and skills that the company has gained over the years, the company offers its services at affordable prices. Whether for consumer products, home appliances, or car accessories, you can rely on these processes for quality production.

Conclusion: Selecting Between Overmolding vs. Insert Molding, and Injection Molding

Overmolding and insert molding are the different techniques that fall under the injection molding process, which is a popular and efficient method of manufacturing consumer goods. As for the cost, injection molding is generally considered to be the most cost-effective method compared to other methods such as CNC machining and 3D printing per part.

Overmolding could be an optimal choice if:

Your part’s surface has different electrical or thermal properties.
It is essential to increase the level of shock absorption or decrease the level of vibrations.
It is necessary to produce a part from multi-colored plastic.
Your part must offer a comfortable, non-stick surface that the other part can easily grip.

Opt for insert molding when:

The substrate can be in the form of wires, electronic components, or circuit boards.
It is preferred not to have to spend the money on a two-shot mold or a 2K, which is more complicated.
You have to tap this part and install threaded inserts.

When the decision has been made to use injection molding for a certain application, the next choice is between insert molding, overmolding, or conventional injection molding. It is important to provide a clear definition of the product application to be able to make a proper choice. All these processes have their own special benefits suitable for various products. Deciding which method is right for your particular product is not always easy; therefore, it is advisable to consult a professional.

Speaking to a SincereTech representative can be helpful due to over a decade of the company’s experience in manufacturing. We can assist you in the decision-making process of your project and determine which process—insert molding, overmolding, or standard injection molding—will be most beneficial for your project.

FAQ’s

Q1. What is the process of TPE overmolding?

TPE overmolding is a process where TPE plastic material is injected into an existing substrate or a plastic part to form a chemical bond with the material in order to increase its durability and usefulness.

Q2. Is 2K injection molding the same as insert molding?

No, Insert molding involves placing an additional part on the substrate, while 2K injection molding involves injecting multiple materials into multiple-cavity molds for the production of intricate parts for vehicles.

Q3. What plastic types are suitable for overmolded?

The most commonly engineered plastics suitable for overmolding processes include high-density polyethylene (HDPE), PEEK resin, Delrin or acetal, polymethyl methacrylate acrylic, commonly known as PMMA, ABS, nylon, and PBTR. These plastics have different characteristics that make them suitable for different overmolding processes across industries like automotive and consumer products.

Q4. Overmolding vs. Insert Molding: Which One Costs More?

Overmolding, however, provides economical scalability at higher production rates for companies, which in turn increases the overall profitability of a company through decreased tooling and assembly costs. Further, it helps with faster production of parts in large-volume runs. If you are going to produce intricate prototypes or low-volume parts, this cost differential becomes apparent due to the requirements of two parts.

13/11/2023/0 Comments/by admin

overmolding, 2k injection molding

What Is Overmolding And 2k injection molding

Brief summary difference between overmolding and 2k molding

While injection overmolding and 2K injection molding (also known as 2-shot injection moulding) share many similarities, they also have some key differences. See below for the difference between those two moulding processes.

Injection overmolding involves the use of a standard single-nozzle injection machine to combine two distinct types of materials into a single solid product. The overmolding manufacturing process means moving the first part (substrate part) or metal inserts to the subsequent mould (overmold) to create the final product. You can use this technology to add a soft-touch grip to a tool handle or to create a product with multiple colors or textures.

2K injection molding, also referred to as multi-shot injection molding, 2-shot injection molding, or dual-injection molding, involves using a specialized 2K injection machine to simultaneously inject two or three materials (colors) into the same mold. In fact, the 2K injection machine actually has two installed moulds. Unlike overmolding, the 2K moulding machine simultaneously injects both materials, fully bonding them together once the moulding process is complete. The 2k molding process, while complex, is characterized by its speed, efficiency, and high quality.

Compared to both manufacturing technologies, 2K injection tooling offers superior quality and production efficiency. However, due to the high cost of the 2K injection moulding machine, overmolding sometimes serves as a substitute. On the other hand, the cost of an overmolded part is higher than that of a 2K injection-moulded part. However, for low volumes of 2-color moulding parts, injection overmolding can utilize any standard injection-moulding machine to produce the overmoulded parts.

When designing multi-material or two-colored plastic parts, it’s crucial to choose the right moulding process based on your part’s design and production needs. Both overmolding and 2K injection molding have their own advantages and disadvantages. Some of the injection moulded prodcuts can only be created with the overmolding process, while some of the injection-molded parts can only be made with the 2K injection molding process; this is depending on the plastic part geometry design. If both moulding processes can produce the plastic parts, the 2K molding process will be the most effective for high-volume production.

Both overmolding and 2K injection moulding can be used to create products with multiple materials or layers, but the key difference is that in overmolding, two materials are formed separately (preloading the substrate to the second mould), while in 2K injection molding, two materials are formed together in the same process (of course, a specialized machine is needed).

What is overmolding (over mold)?

Overmolding, or over mold is a manufacturing process that involves molding one plastic over another material to be merged to form a single end product. In plastic overmolding, two separate moulds are required: the substrate, which is the first tool, and the overmould, which is the second mould. Typically, the second mould is made of thermoplastic elastomer (TPE) material, but this is not always the case. If the substrate is machined metal or brass components, then we normally call this insert molding, and insert moulding only needs one mould (over mould) to finish the manufacturing process.

The materials most commonly used for plastic overmolding are thermoplastic elastomer (TPE), rubber, or the same material as the substrate but in different colors. Today, we will primarily focus on the overmolding technology that utilizes TPE materials, which are widely used in various industries. The rigid substrates can be made of a wide range of materials, including polyethylene (PE), polypropylene (PP), polycarbonate (PC), nylon (PA6 or PA66), acrylonitrile butadiene styrene (ABS), polymethylmethacrylate (PMMA), polystyrene (PS), high-impact polystyrene (HIPS), polyphenylene oxide (PPO), acrylonitrile butadiene styrene (ABS), or any other special-purpose material that can be used as substrates.

Overmolding utilizes the injection moulding process to inject one plastic material (OverMold) over another material (substrate). The overmolding plastic material normally uses TPE, rubber, TPU, or the same material but in different colors. Overmoulded materials will make a strong bond with their substrates, ensuring long-term durability and optimal performance in their intended environments. The use of overmolding removes the need for adhesives when connecting thermoplastic elastomers (TPEs) to hard substrates. The overmolding technique simplifies the molding manufacturing process, lowers costs, and allows for more design flexibility.

The types of overmolding

Types of overmolding include two-shot sequential overmolding, insert moulding, and multi-shot injection molding (2K and 3K injection moulding, or more).

Two-shot sequential overmolding

In two-shot sequential plastic injection overmoulding, the molding machine injects the first plastic resin into the first mold cavity (substrate mould); after the material cools and forms the first plastic shape, it then opens the tool. All of those molding processes are the same as the traditional injection moulding process.

Once the first substrates are completely finished and cooled, insert the substrate into the second mold (overmold), close the tool, and then inject the second material. The process is also the same as the traditional molding process; the difference is preloading the substrate into the cavity before the manufacturing process begins.

All of those moulding processes will be done with traditional injection machines.

Inert overmolding

Insert over-molding uses pre-formed inserts or metal inserts placed into the mold before injecting the second material; if the inserts are metal or brass, then we call it metal insert molding. This overmolding process, which we used a lot, for example, metal screw insert moulding and filter insert molding, this type of over-molding uses a traditional injection moulding machine to proceed, which puts the metal inserts into the mold cavity during the single injection molding cycle.

Like the below picture is showing, the insert overmolding with metal inert. This type of overmoulding only requires one injection mold; however, if the first insert is made of a plastic part, we will need an additional mold for the first plastic insert part.

Multi-shot injection moulding or 2k injection molding

Multi-shot injection molding, sometimes called 2-shot injection moulding, is also a type of overmolding. This molding technology requires specialized injection moulding machines, which have two injection units. The injection barrels can be parallel or perpendicular to each other. There will be two injection moulds assembled in this machine; one injection tool makes the substrate, and the other one is for the overmolding process.

The moulding machine injects the first plastic resin into the first cavity, also known as the substrate mould. Once the material cools and forms the first plastic shape, it opens the tool. This process is identical to the traditional injection manufacturing process. Once the moulds are open, the movable half rotates 180° without ejecting the substrate. Next, it closes the molds and initiates the second injection, also known as the overmold. Simultaneously, it injects the first shot. Once the second cavity completes its molding process, it opens the tools again and ejects the overmoulded product from the overmold. During this process, a new substrate is generated for the second cycle.

This is a completely molding cycle for the 2k injection moulding process.

TPE overmoulding

TPE (thermoplastic elastomer) plastic materials are used a lot in the injection molding field, especially for the overmolded parts. In the overmolding market, over 80% of overmolded parts are made by TPE over molding,

TPE Over molding is the injection moulding process where TPE (thermoplastic elastomer) is formed onto a rigid material (for example, PC, PA66, or ABS material) according to the specific requirement. The overmolded TPE will strongly bond with the first plastic and maintain its final use purpose. To prevent the TPE material from stripping off from the second material, material selection and part design are very important.

A TPE overmolding manufacturer will consider all relevant factors when selecting the optimal moulding manufacturing method for a plastic injection molding part, choosing between 2K molding and the overmolding process. Critical factors include production capacity, material selection, available equipment, and labor costs.

Normally, the overmolding process is the most popular choice when total production volumes are less than 50K. This number is only a reference and not a definitive one because it depends on the size and complexity of the part design. For higher volume production requirements (total volume over 200,000 units), a 2-shot injection moulding process will be a better option; of course, this is still dependent on the part design because some parts can only be made with an overmoulding process; for example, the below part can only be created with the overmolding process.

In every TPE overmoulding or 2K injection molding process, the number one issue is to achieve maximum adhesion between the TPE and the substrate. Some TPE overmoulding may have significantly different bond strengths between multi-shot and overmolding. Even if an excellent bond is produced with two-shot molding, the same material may have a low bond strength when using overmolding. Thus, to make high-quality finished overmolding and 2K moulding products, a thorough understanding of TPEs, part design, engineering plastics, and the specifics of the moulding process is important.

TPE Overmolding materials seletion tips

As we know to make high quality TPE overmolded product, both TPE and substrate materials are most important, the number one factor to define the quality of overmoulded part is how good the mergeration between two matreials, if the TPE is easy to strip off from the substrate then the material will be issues, below there are some tips for meterials selestion, following thsi tips you will find the best suitable material for overmoulded part.

Thickness of TPE overmolded part

Designers frequently request the softest TPE. They don’t realize that a TPE’s soft durometer doesn’t provide much to “cushion” below a particular thickness (usually less than 0.1mm). Thinner TPE overmoulded part feel harder—the hardness impact depends on thickness. Multiple closely spaced ribs can produce the illusion of thickness without utilizing much material. Many kitchen utensil handle use this method.

Hardness of TPE plastic material,

There is a softness of TPE material that you need to select when you make TPE overmolding, especially TPE thickless, which is more than 0.5 mm. To have a good touch feel, you may need to test different types of TPE shore A material, unless special function requirements, normally we use in the market will range from TPE Shore A 40 to 60; if too little, that may eash to strip off from the substrate; if hardness is too high, the touch feel may not be good enough.

Substrate material selection tips

Compared to TPE material, substrate materials will be easier to choose; most materials can be substrates, including nylon/PA (PA66 or PA66 GF30, PA6 or PA6 GF30 plastic), Polycarbonate (PC), Acrylonitrile Butadiene Styrene (ABS, PC/ABS, Acetal (POM), PMMA, and so on. The final substrate material selection is dependent on the final purpose. If you are uncertain about the optimal material for your TPE overmolded parts, please reach out to us and we will provide you with some recommendations.

Surface finish on substrate and TPE overmold

Surface finish on the substrate will also affect the adhesion of TPE rubber. The stronger the adhesion, the less likely it will strip off, normally will be good polishing between merge surface between TPE and substrate, on the TPE cavity side, soemtime surface finish will effect to the TPE overmold as well, sometime higi polishing to the TPE cavity mold, the TPE overmolding part will stick to cavity side, add some small VDI texture will improve this.

TPE overmolding part design tips

Part design, as previously mentioned, plays a crucial role in creating a high-quality TPE overmolding product. Generally, the design of the substrate part is similar to that of other plastic injection tooling parts. For further details, please refer to the page on plastic part design for injection molding. But there are some factors on the merge area between the substrate and TPE overmoled area; there is no standard design for this era since different parts have different geometries, but there are some key points that you need to think about when you do the overmoled part design. Those factors will be:

How to seal the TPE overmolding well and provent from flash When you do the overmoling part design:

TPE material easily exhibits flash (0.03 mm gap), and bondable TPE materials meet more stringent criteria than standard TPE polymers. The same holds true when designing parts. Unlike traditional part design, two-component part designs must account for shrinkage from two different thermoplastic materials. Both substrate and over-moulding have their own gate and runner systems, which must be tailored to the individual material properties used.

To meet the best cycle time, substrate and overmolding wall thickness should be consistent. In most over-molding applications, 1-3 mm wall thickness ensures satisfactory bonding. Thicker pieces should be cored out to reduce shrinkage, weight, and cycle time. To avoid backfills and gas traps, wall thickness transitions should be gradual. Add radius to the sharp coners to reduce stress issues. Avoid deep, unavailable blind pockets or ribs. Long draws should have a 3-5 degree draft angle for easy demoulding. In overmolded compounds, deep undercuts can be designed if an advancing core is used when the mold opens, the part has no sharp corners, and the elastomer bends during ejection.

Most TPE compounds have significant flow direction tool shrinkage and moderate cross-flow shrinkage. After ejection from the tool, the over-moulding compound may contract more than the substrate. This can stretch the substrate, usually in the overmolding material’s direction. This is especially true for long, thin parts or components with a low-modulus substrate or one thinner than the over mold. Use higher-modulus substrate materials and stiffening ribs to mitigate this. Thinner coatings and lower-hardness over-mould grades assist. Relocating the gate to affect TPE flow may also help.

If you can enhance the design to ensure a tighter bond between the TPE material and the substrate, such as by increasing the cross-sectional area, without compromising its functionality or appearance, it would be beneficial. Below is one of exmple of overmolding part design tips.

Avoid designing too many separated areas on the TPE overmolding part, as this can complicate the overmold manufacturing and moulding process. Especially many areas are designed to the parting line area; this will be hard to solve the flash completely when you design the TPE overmoulded part, designing as simple as possible, unless some function purpose.

Tips for overmold desgin:

When we design injection mold for overmolding parts, the first mold (substrate tool) we will add shrinage rate according to plastic shrinakge rate, but for the over mould (second tool), we will not add any shinakge rate on the injection over mold.

Overmolding cost

The base cost of an overmolding is not a fixed number that will be the same for every application. It has a varying value that can fall between 1 and 10 dollars.

This is an extremely wide price bracket. The right value changes based on several components involved in the overmolding process. These factors that influence the cost are:

Injection molding Equipment

The upfront cost of equipment for injection moulding can change greatly depending on its application and type.

There is little-scale injection moulding equipment that businesses keep in house. Then there are big overmolding machines generally used by service providers and those in the big-scale manufacturing industry with large production volumes.

Professional industrial overmolding equipment costs between $50,000 and $200,000. There may be shipping costs involved. These machines are not for amateurs and hobbyists, as they need skilled operators.

Overmold manufacturing costs

While the overmolding equipment is a one-time investment, creating the over mold according to each custom design is an additional cost, and each single product design will require a unique over mould. It is an expense for every different part produced. So, over mold manufacturing costs are one of the most vital driving factors for overmoulded parts.

This over mold cost can vary depending on the part design, part size, and quality required to create the moulds. Generally, three factors are employed for this objective, which are listed below:?

Design complexity

Highly complex designs with more cavities and top mold polish result in extra costs. Such designs need development, research, and technical skill. For this objective, you can hire a professional for the design process. Both options incur expenses.

Part size

Over mold is the same as other injection moulds; a large size will require a large mouldbase and moulding machine, which will increase the over mold cost and unit moulded part cost.

Labor costs

Most steps involved in overmolding are automated and run by software systems. For example, CNC machines are run by computer numerically controlled programs; 3D printers run on their own programs; and injection molding also has mechanical processing.

Final summarize for the overmoulding cost

If you are looking for over-molded parts or over mold for your custom injection molding parts, then you do not need to pay any cost on the injection molding equipment, because your over molding supplier should have this, but you need to pay for the over mold cost, over-moulding process cost, materials cost, packing cost, and so on. If you want to know the price of your overmolding project, please contact us and we will quote you in 24 hours.

Metal insert moulding

How to reduce overmolding cost

Overmolding is the preferred manufacturing process due to its cost-effectiveness and reliability.

While the process is affordable compared to its alternatives, you can further decrease the costs. For that objective, here are some pointers that you need to take into account:

Optimizing the CAD design

A single part can be approached via different CAD designs. Anyway, not every design idea is perfect. Some designs for the same part may lead to time and resource waste. So, simplifying part complexity via efficient CAD design ensures optimal utilization of resources.

Reducing part size

Bigger parts are not always excellent parts. When the size of the parts rises, so does the expense of the injection molds needed for the parts. If the same process can be accomplished by decreasing the part size, it is a good idea to opt for it.

Resuing over molds

Make full use of the over molds by reusing them for many applications. You cannot just use the same mold for the same part but also for similar parts as well. This can be performed by making adjustments or molding wherever possible.

Using DFM analysis

DFM stands for design for manufacturing. DFM in overmolding refers to producing a part that serves the objective of the customer and is within their stipulated budget.

For DFM, analysts consider many factors based on science, art, and technology to find the most successful design, resulting in reducing injection over mold costs. Go to design for manufacturing page to know more.

Both over molding and 2k injection molding are very similar processes, sometime both moulding processes can work on the same part, but something can only be created with single overmolding or 2K injection molding, this is completely depending on the part design.

Advantages of injection overmolding

Compared to 2K injection molding, over molding is easier to make. You can use a normal injection machine to make two or three different colors in one molded part or two or three different materials in one end part.
For some small quantities of two-color molding part projects, you do not need to invert or hire a 2K injection molding machine; using the overmoulded process is the best and most cost-effective way to meet customer requirements.
It increases the design diversity and also exalts the end product in many material compositions.
With reduced assembly costs, there are fewer secondary activities or processes carried out on the end products. This reduces the cost of labor. Also, after manufacture, no more costs are incurred.
The parts have a high level of stability and constitution since, after being left to mechanically interlock, they become one.
Products overmolded using plastic have high resistance to vibration and shock due to the plastic resins having been structured perfectly.
The plastic moulded parts are more reliable because there is no bonding at the production stage.
The end items are of the desired standard, such as eye-catching designs and firm components.

Disadvantage of injection over moulding

Since the over moulding process involves moving the first substrate part to another over mold, the tolerance is not as good as in the 2K injection molding process.
The production capacity is not as efficient as 2K injection molding, as it requires robots or manual labor to insert the substrate into the overmoulded tool. This will take time, and the molding parameter is sometimes not stable, especially when two or more substrates are in one tool. This will lead to additional problems and a higher waste rate, resulting in twice the amount of waste (from the substrate and overmolded material).
With the overmolding process, there are fewer available choices in terms of plastic compatibility. Some materials may not bond well together or may not be able to withstand the high temperatures and pressures of the injection molding process.
There are no secondary practices carried out on the end products of over-moulding. When the plastic material becomes cold, activities and adjustments come to a complete halt.
In cases where products are scarce, it is expensive to run such an operation. Sincerely, you need someone to put the substrate into over mold, so the cycle time and production cost are increased accordingly.
The overmolding process normally requires two molds, one for substrate and one for over mold, so the initial tooling cost will be higher.
Overmolding is a more complex process than traditional injection molding, requiring precise coordination between the two injection systems and a proper mold design.
If there is an issue with the overmolding process, troubleshooting and fixing problems with overmolding can be more difficult than with traditional injection molding.

What is 2k injection molding? (Two-shot moulding)

Two-shot injection molding, or 2K injection molding, is a manufacturing process used to create two colors or materials into one plastic. This two-shot molding technology blends two materials or two different material colors into one plastic part by using a 2K injection moulding machine.

The chemical bonding process involved in this process is very important because it is capable of combining two or more materials into one part. When using the 2K injection molding technology process, material selection will be an important factor in the success of the project or not.

Benefits of 2K injection molding

2K injection moulding provides a number of benefits over traditional one-material injection molding. Some of these benefits contain:

Cost-effective

The 2-step process needs just one machine cycle, rotating the primary mold out of the way and putting the secondary mould around the item so that the second, compatible thermoplastic can be inserted in the second tooling. Because the method uses only one cycle instead of separate machine cycles, it costs less for any production run and needs fewer employees to make the end product while delivering more items per run. It also ensures a powerful bond between the materials without the need for additional assembly down the line.

Improved efficiency

Two-shot molding permits multiple components to be created with one tool, decreasing the amount of labor required to run your parts and eliminating the need to join or weld components after the molding process.

Better quality

Two-shot is carried out within one tool, permitting lower tolerances than other molding processes, a high level of accuracy and repeatability, and reduced scrap rates.

Complex molding

Two-shot molding permits the creation of complex mold designs that incorporate different materials for functionality that cannot be achieved via after-molding processes.

Disadvantages of 2K injection moulding

2K injection molding has many advantages, but like everything, it has its pros and cons.

A disadvantage of 2K injection molding is that the mould costs are higher than traditional injection mold. because 2K injection tooling requires two molds, the first shot and the second shot (that is why we call it two-shot molding), and making 2K injection molds are more difficult than making two separate traditional molds because those two moulds will run together in the same machine (a two-shot injection moulding machine). so it needs two moulds to switch over without any problem.

Additionally, the 2K injection molding process must use a 2K injection machine, which also makes the machine more costly and requires a special technical operator to adjust the machine. This is also a higher cost than traditional injection tooling. Ultimately, we recover the 2K injection molding costs by reducing labor and assembly costs, as the manual application of, for example, a seal is no longer necessary. This eliminates an assembly step.

Another disadvantage of 2K injection molding is that it makes the recycling of plastic items difficult because often two different plastics are gathered. Even when the plastics are “from the same family,” the quality of return flows will be very low, which makes it hard to reuse the plastic for a high-standard application.

How to choose overmolding and 2K injection molding services

You may have questions about when you need to use over moulding and when you should use the 2K injection molding process. Here are some simple suggestions:

If the quantity of the overmolding or 2K molding part is only a few thousand or ten thousand, it is recommended to use the overmolding process instead of 2k moulding process as it can significantly reduce mold costs.
If you require more than 500,000 parts, 2K injection molding is the most cost-effective manufacturing process. This is due to the high labor costs associated with overmolding and the high initial cost associated with 2K moulds, two-shot injection moulding machines, and related equipment.
Overmolding is the only method available for some parts, while the double injection molding process is required for others. This depends on the part design structure. If you’re unsure, send your data to info@plasticmold.net. We can check this for you and provide a price for your reference.

Looking for over moulding or 2k injection molding service?

Sincere Tech is one of the best injection molding companies in China. If you are looking for overmolding, insert moulding, 2K molding, or any other custom molds, send us your 3D design drawing and your requirements; we will never share your data with anyone else. We are willing to sign an NDA document to ensure the safety of your project.

We will offer you the most competitive price for high-quality overmoulded parts, 2K tooling and moulding, plastic tooling, and plastic parts for the long-term business relationship, and we will suggest the best injection manufacturing process for your products.

More than 18 years of experience providing plastic mold making and custom mold services in overmolding, 2K moulding, die casting, machining, and so on, plus 18 years of fluent technical English communication (technical English communication is very important to work with worldwide customers).

Small orders are accepted. Main export markets: Asia, Australia, Central and South America, Eastern Europe, North America, Western Europe, and the worldwide.

04/05/2021/by admin

Injection molds, Insert mold, Insert molding, overmolding, precision injection molding

Precision Plastic Injection Molding

What is precision plastic injection molding?

Precision Plastic Injection Molding is tight tolerance requirement plastic injection molding parts. Normally tolerance on the plastic molding part is around 0.05-0.1mm, if the part tolerance requirement is about 0.01-0.03mm, that means this is precision plastic injection molding, to make high precision plastic injection molding parts, the first thing is making the precision injection mold, all of the mold components must have tolerance within 0.005-0.01mm.

This is min requirement for high precision plastic injection mold after mold is completed finished, then take mold trial to verify the dimension according to 2D drawing requirement, to trial the mold and make stable tolerance.

High Precision plastic injection mold is number one key point to making high precision plastic injection molding parts, but not limited to this, you still need use high precision injection molding machine to produce the part, by this two min requirement we can make sure that we can make precision injection molded plastics continually, there are few issues that we make still need to know for the high precision plastic injection molding.

Plastic precision Connector-overmolding

Question I:

The determination of the structure of the precision plastic mold is the key, and the overall structure is the embodiment of the final effect of the product: the determination of the overall structure of the mold, the determination of the gate system, the determination of the ejection system and the determination of the water transportation system, and others should be conducive to the post-processing orientation of the product.

Question II:

What about the feeding problem? First of all, we will choose a reasonable injection scheme according to the structure, weight, volume, and cost of the product, which can meet the requirements of customers as well as the requirements of quality.

Second, we will design in strict accordance with the injection design standards: the layout of the runner should be uniform, especially the size of the cross load surface of the main and sub runner, the shape and size of the gate.

Question III:

What about the ejection problem? Firstly, we will determine the ejection mode according to product orientation and structure. Secondly, we will evaluate the ejection balance and coexist with other systems, such as interference with water transportation and recycling marks, date clock, etc.

Question IV:

The design of the water channel system is based on four requirements (the cooling line should be as balanced as possible. The water cooling line shall not interfere with other mechanisms. The water channel equipment shall meet the customer’s standards and be easy to install. Each water channel line shall be displayed with identification numbers or marks (in and out).

Question V:

How to ensure the manufacturing accuracy of the mold and the accuracy of the molding products to get precision injection molding, this mainly depends on the manufacturing accuracy of the mold cavity, the insert, and the mold core size. The accuracy of the mold cavity number or the accuracy of the parting line will directly affect the size of the product. Firstly, we need to make the manufacturing process plan and flow chart.

Each completed manufacturing process must be fully inspected and the data inspection list must be recorded in the datasheet. After the manufacturing is completed, the workpiece shall be processed and maintained.

The design of the parting line of plastic mold is also an important part. If the design is not reasonable, the part is not easy to demoulding or even damage the mold. Here are the design principles for the parting line of mold

It is convenient to eject out the plastic part and simplify the structure of the plastic mold. After the demoulding direction is selected, the position of the parting line should make the plastic part fall done without any interference, like sliders, etc.

For the plastic part with high coaxiality accuracy, the parting line should be selected at the position where two diameters can be placed on the lower mold or upper mold at the same time.

When the precision plastic injection molding along the height direction is required to be high, the half overflow cavity should be used. If the transverse flash is formed at the parting line, it is easy to ensure the height precision, while the non-overflow cavity is not easy to ensure.

When the radial dimension accuracy is high, the influence of flash thickness on the accuracy of the plastic part should be considered, as shown in the figure. If the vertical parting of plastic parts is easy to ensure, the horizontal profile is difficult to control due to the thickness of the flash, which affects the accuracy of plastic parts.

Ensure the appearance of the plastic part, it shall be easy to clean the flash and not easy to damage the appearance. The flash produced by the parting surface as shown in the figure shall be easy to clean and not easy to damage the appearance of the plastic part.

It is convenient for the manufacture of plastic mold and the processing of forming parts. The improved parting surface makes the processing concentricity of plastic mold low, easy to manufacture and the flash does not damage the appearance of plastic parts.

Ensure the strength of the formed parts, for example, when determining the parting surface, avoid the thin wall and sharp corner of the formed parts.

In addition to the design elements of general molds, the following points should also be considered in the design of precision injection molds:

Adopt proper mold dimension tolerance;
Prevent forming shrinkage error;
Prevent deformation of injection part;
Prevent the deformation of demoulding;
The manufacturing error of the die/mold is minimized;
Prevent the error of mould precision;
Maintain mold accuracy.

Prevent the error of mold precision; classification of processing molds in plastic mold factory and requirements of various points for attention

There are many kinds of plastic injection molds, which can be roughly divided into ten categories. According to different requirements of a part material, physical and chemical properties, mechanical strength, dimensional accuracy, surface finish, service life, economy, etc, different types of injection mold are selected.

The plastic mould with high precision needs to be processed by a high precision CNC machine, and the material and molding process of the mould have strict requirements. Mould technology is also needed to design and analyze.

Some of the parts have special requirements during molding, so advanced technologies such as hot runner, gas-assisted injection molding, nitrogen cylinder, etc. are needed for plastic mold.

Plastic mold manufacturers shall have CNC machine tools, EDM machine tools, wire cutting machine tools, and CNC profiling milling equipment, high-precision grinder, high-precision three coordinate measuring instruments, computer design, and related software, etc.

In general, large metal stamping dies (such as automobile cover part die) should consider whether the machine tool has a blank holder mechanism, even edge lubricant, multi-position progressive, etc. In addition to the punching tonnage, the punching times, feeding device, machine tool and die protection device should be considered.

The plastic mold manufacturing capacity and process of the above are not possessed and mastered by every enterprise. When choosing a cooperative plastic mold manufacturer, we must know its processing ability, not only look at the hardware equipment, but also combine the management level, manufacturing experience, and technical force.

For the same set of mould, there is sometimes a big gap in the quotation of different mould manufacturers. You should not pay more than the value of the mold, but also should not be less than the cost of the mold. Plastic mold manufacturers, like you, want to make a reasonable profit in business, ordering a set of molds with a much lower price will be the beginning of trouble. You should start with your own requirements and measure them comprehensively.

If you have a plastic parts that needs precision injection molding manufacturing services, you are welcome to contact us, Sincere Tech is customized precision plastic injection molding company in China. We offer precision injection molds and molding services to customers all over the world.

01/01/2020/by admin

China mold, 2-Shot Injection Molding, custom injection molding, Gas assist moulding, hot runner molding, Injection Mold China, Injection Mold Maker, overmolding, plastic injection mold, plastic mold, Plastic mold china, plastic molding, plastic molding china, plastic mould, two shot mold, Two-Shot molding

Plastic Injection Molding Service

Looking for plastic injection molding service?

The excellent quality of our plastic molds and molded parts, coupled with our experience and the performance of our services give us today a high international recognition. Indeed, the company is specialized in International Business and has customers all over the world. SINCERE TECH has very high standards of quality control and always runs long tests to make sure that our Plastic Injection Molding Service reaches all the expectations of our customers. We believe that the quality of a company and its products are seen through time and this is why we like to build strong long-term partnerships with our customer

What is plastic injection molding process?

Plastic injection molding is a manufacturing process in which melted plastic is injected into a mold and then cooled to form a solid part. The mold is created from a metal or plastic tool (1.2344, H13, NDK80, etc.) and is typically made in two halves that are clamped together. The plastic material is heated in a barrel and then forced into the mold under high pressure where it cools and solidifies into the desired shape. This process is used to produce large quantities of identical parts with high precision and repeatability.

When do you need plastic injection molding service?

You may need plastic injection molding service when you require mass production of plastic parts with consistent quality and high precision. This process is ideal for producing large quantities of the same part, as the mold can be used multiple times to produce identical pieces. Additionally, plastic injection molding is well-suited for producing complex and intricate shapes that would be difficult or impossible to achieve with other manufacturing methods. This process is often used in various industries such as automotive, consumer goods, medical devices, and electronics.

plastic molding services

Benefits of plastic injection molding service

The benefits of plastic injection molding service include:

High volume production: Plastic injection molding is ideal for high volume production of identical parts, as the mold can be used multiple times.
Consistent quality: The process is highly repeatable, which leads to consistent quality of parts produced.
Complex shapes: Plastic injection molding can produce complex and intricate shapes that would be difficult or impossible to achieve with other manufacturing methods.
Material flexibility: A wide variety of plastic materials can be used in the injection molding process, including thermoplastics, thermosets, and elastomers.
Cost-effective: The process is efficient and cost-effective for producing large quantities of parts, as the cost of the mold can be spread over many parts.
Precision: The process can produce parts with high dimensional accuracy and minimal tolerance variation.
Automation: Plastic injection molding machines can be automated for increased productivity and reduced labor costs.

Plastic injection molding is a versatile and reliable manufacturing process that can provide significant benefits for producing large quantities of complex and high-precision plastic parts.

Plastic Injection Molding Service in China

We are the manufacturer of our own moulds (toolmaker or plastic injection tooling) and support the production of Injection molded parts allowing reducing your numbers of suppliers. Our injection machines have clamping forces going from 60 to 1050 Tons (2000 Tons outside). Plastic injection molding is the process of producing parts from thermosetting and thermoplastic materials.

Our qualified teams of Designers, Quality controllers and our Research and Development Department allow us to complete our policy: achieving Customer Satisfaction through Improvement and Innovation. The quality of our products and organization permits us to obtain quality certifications (ISO 9001, ) and be awarded numerous times of “Quality Supplier” from different customers. We integrate constantly new resources into our process in order to anticipate any future need of the plastic injection molds market and we became one of the most innovative companies in the sector. The modernity and the organization of our facilities allow us to adapt very quickly to the customer’s needs.

SINCERE TECH has always the objective to stay one of the innovative leaders of the sector and play an important role in our customer’s development. The firm can now propose a total solution from mould design to the semi-finished product (All in-house). SINCERE TECH is always willing to integrate new processes to the solution proposed by staying aware of new technologies. If a customer has a special requirement, we will do everything to fulfill its needs.

Plastic Materials /Commodities

We are used to working with all the classic and less classic plastic materials except PVC (PP, PE, PC, ABS, PC+ABS, PA 6, PA 6.6, PBT, PMMA, TPU, PC+GF, AS, PTFE, POM, PEHD, PEEK…). Our main suppliers are Sabic, Bayer, and Chimei.
About the steel used for our moulds, for export plastic molds we work only with the best steel suppliers like Assab (Sweden), Buderus (Germany), Daido Steel (Japan) LKM( the biggest one in China). For our standard component suppliers, we work with Hasco and DME.

We are used to working with our suppliers the same way we work with our customers. It means good long-term relationships with high-quality policy.

Complex moulds: SINCERE TECH has a rich experience in difficult plastic mould and parts, complex moulds and is an expert in finding solutions to your issues. SINCERE TECH is a real specialist in difficult tooling. To give a classic example: many design companies create plastic products without thinking about mould construction. Then, when the designs are sent to toolmakers, it can be hard for them to make the exact parts (Difficult design, many sliders, many lifters, double injection with materials non-bonding well together, many details in awkward places…).

Most of the classic toolmakers will accept the parts and say that they are able to do it. And then, they will have problems with the plastic injection mould construction, the lead time will be extended and the quality of the tool will not be as expected. Often, these companies have to contact SINCERE TECH to help them to resolve their problems. If you are not sure about the complexity of your part, be sure about your mould maker’s professionalism. SINCERE TECH works closely with its customers in order to resolve any issues.

Thin Wall injection molding: it permits a precise, very accurate molding of plastics and gives better details to the product. This is the name referring to products with a wall thickness lower than 2mm. Usually, the flow is quick, permits a short cycle time and a cost-saving.

Hot runner mold: the special process of injection of plastics where the plastic is kept hot when going through cavities of the mould while the rest of the mould is getting cold to solidify the plastic part and create the molded part: this permits to save plastic material. This is mainly used for parts with medium or large sizes. We are used to working with all popular companies like Yudo, INCOE, Synventive, Husky, HRS… We also have the technology to make our own hot runner systems if the production of the parts (Molding) is made in-house. This again allows our customers to save costs.

Optical Lens Molding: precision molding for glass plastic. This is the technique to produce transparent plastic molded parts (For example Security cameras parts such as the dome cover or also phone frames).

Gas-assist Injection Molding: the plastic parts are gas-assisted molded which means that gas (Most often is nitrogen) is injected at the final stage of the part creation process. It permits to reduce the cycle time, the product weight, the risk of deformation and also the pressure tons injection needed. Moreover, it makes the part’s structure stronger with a better look.

LED/LCD frame molding: injection of plastics used for example to manufacture television screen monitors, computer back-light modules, GPS frames…

IMD, IMF, IML, IMR Molding: In-mold decoration. The decoration of the part is made inside the mould through a film. The film is printed before the molding with the designs wanted. It permits better productivity and extends the decoration’s lifetime. If the customer wants to change the design/decoration of the part, it is not necessary to make another mould but only to change the film. SINCERE TECH is experienced with In-mould forming, in-mold-labeling, and in-mold by roller.

Overmolding: this technique permits to join several components together with a thermoplastic material. This reduces assembly and labor costs. Because the parts are made together, this allows less risk of improper termination or misalignment and increases the design flexibility. Moreover, thermoplastic provides better resistance to vibration or shocks. This technique permits to increase resistance, reduce costs and weights.

Insert Molding: this is a technique where a small part (Stamping part, optical part…) is added or inserted to the Injection molded part.

Two-Shot Molding: 2 independent injection units using 2 different materials and/or colors. The first material is injected; then, the mould rotates and the second material is injected to make 1 part. It permits a 2-colour-molding or also called double injection, 2 shot molding, two-shot injection, overmolding, 2K injection, two colour injection, bi-injection, dual shot molding or multi-component molding.

CNC Technology. CNC is an abbreviation for Computer Numerical Control. This is a machine extremely accurately controlled by computer programs permitting a CAM (Computer-aided Manufacturing) through a CAD (Computer-Aided Design). Any plastic injection tool manufacturer uses it but the value-added of SINCERE TECH is the experience, professionalism, and training of the staff.

FMMS Molding or can be called RHCM (Rapid Heat Cycle Molding): excellence surface appearance: permits to take off the welding line. This process is integrated into the molding to save time. It is used for example for clear plastic parts.

US Welding: Ultrasonic Welding: process to weld/ join/ assemble plastic parts thanks to ultra-sounds.

Silk-Screen Printing: this is to print logos or designs on parts.

Dip-Coating: this is the process of putting the component inside a liquid solution to apply a thin film on it. It permits to manage, change the hardness, the strength of the part by protecting it and expanding the lifetime of the product. Then, the excess liquid has to be drained and evaporation of the solvent is done to create the thin layer.

Laser Etching: this process is made for cutting a shape, a pattern, an image on the plastic part. It is also called laser graving.

Sputtering coating: this is the process of creating a very thin layer of conducting material on the component. It is also called Plasma Enhanced Chemical Vapor Deposition (PECVD) and can be done with most metals like aluminum, stainless steel, copper…

EMI shielding: protect parts from electromagnetic interferences. It is used to protect electrical signals from the outside world. For instance, we use it with marine radars for Garmin.

Waterproof technology: SINCERE TECH has the experience to make water-resistant parts and is able to ensure in-house tests thanks to the IP68 tests.

Sub-assembly: this is the pre-assembly of a component who will be later on being assembled in a larger product.

R&D: SINCERE TECH has its own Research and Development department in order to work with the customers on their projects, advise them on designs, resolve issues and study the feasibility of those.

Quality Control: We have very high standards of quality control in order to respect any requirements from our customers. We have a 100% quality control on our plastic molded parts, it means we control any part coming out of our production.

At Sincere Tech China mold maker, our unwavering commitment to staying at the forefront of the plastic mold industry drives us to embrace advancements and anticipate future trends. We continuously explore innovative materials and composites that offer enhanced performance and promote sustainability. By investing in ongoing research and development, we consistently deliver cutting-edge solutions that meet the evolving needs of our valued customers. As a trusted injection mold supplier in China, we take pride in our unwavering dedication to excellence.

Aligned with our sustainability goals, we place a high priority on environmentally friendly practices. We actively seek out sustainable alternatives, such as biodegradable polymers, and implement recycling initiatives to minimize the environmental impact of our manufacturing processes. By choosing our custom injection molding services, you can align your brand with sustainable manufacturing practices and contribute to a greener future.

Ensuring quality is our topmost priority, and we maintain rigorous quality control measures throughout the entire manufacturing process. Equipped with state-of-the-art facilities and staffed by skilled technicians, we subject each product to thorough inspection and testing. This guarantees exceptional performance, reliability, and customer satisfaction.

When you choose Sincere Tech as plastic injection molding service partner in China, you can expect the highest level of professionalism, expertise, and innovation. Our dedicated team is committed to helping you bring your ideas to life, delivering superior products that excel in performance, durability, and cost-effectiveness.

Partner with Sincere Tech Mould suppliers for your custom plastic injection molding service, and benefit from our comprehensive capabilities, unwavering commitment to quality and sustainability, and our drive to exceed your expectations at every step of the process. Together, let’s bring your innovative ideas to life.

19/04/2019/by admin