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Injection Mold

In modern industrial production, mold is an important technology used in shaping products (including metal products and nonmetal products) for all of the industries. Meanwhile, it is the ‘magnifying glass of efficiency and profit’ to the raw material and equipment, because the value of the final product made in the mold is often tens of, even hundreds of times as valuable as that of the mold itself.

The mold industry is the basic industry of the national economy, and it is called ‘the mother of industry’. Every aspect of human life such as clothes, food, housing, and transportation is closely connected with the mold industry. Therefore, the level of injection mold technology has been a significant symbol to measure a country’s developing level of mechanical industry.

And mold can be divided into two kinds of them: mold for metal products and nonmetal products.
The metal products mold include cold-press mold, pressing mold, forging mold, press casting mold, precise casting mold, stamping tool, punch tool, and dust metallurgy mold, etc. These kinds of mold have extensive apply-cation in electrode-cranial products, automobiles, aviation instruments, and other metal products.
The nonmetal products include plastic injection mold, ceramic mold, rubber mold, glass mold, food mold, and ornament mold. These kinds of molds have extensive apply cation in our lives, at this page we are talking about injection mold. this is the most papular modern technology which used in our life everywhere.

An injection mold used to form a plastic product using the injection molding process. A standard injection mould is made of a stationary or injection side containing one or more cavities and a moving or ejection side.

The resin, or raw material for injection moulding, is usually in pellet form and is melted by heat and shearing forces shortly before being injected into the mould. The channels through which the plastic flows toward the chamber will also solidify, forming an attached frame. This frame is composed of the sprue, which is the main channel from the reservoir of molten resin, parallel with the direction of the nozzle, and runners, which are perpendicular to the direction of the nozzle and are used to convey molten resin to the gate(s), or point(s) of the gate and feeding the molten material into the mold cavity. The sprue and runner system can be cut off and recycled after molding. Some moulds are designed such that it is automatically stripped from the part through the action of the mould. For example, the submarine gate or banana gate, if using hot runner systems then there will be no runners.

The quality of the injection molded part depends on the quality of the mould, the care taken during the moulding process, and upon details of the design of the part itself. It is essential that the molten resin is at just the right pressure and temperature so that it flows easily to all parts of the mold. The parts of the injection mold must also come together extremely precisely, otherwise small leakages of molten plastic can form, a phenomenon known as flash. When filling a new or unfamiliar mould for the first time, where shot size for that particular mould is unknown, a technician should reduce the nozzle pressure so that the mold fills, but does not flash. Then, using that now-known shot volume, pressure can be raised without fear of damaging the mould. Sometimes factors such as venting, temperature, and resin moisture content, can affect the formation of flash as well.

Injection Mold Material

Traditionally, molds have been very expensive to manufacture therefore they were usually only used in mass production where thousands of parts are being produced. Injection Molds are typically constructed from hardened steel or aluminum. The choice of material to build a mold is primarily one of economics. Steel molds generally cost more to construct, but their longer lifespan will offset the higher initial cost over a higher number of parts made in the mold before wearing out. Aluminum molds can cost substantially less, and when designed and machined with modern computerized equipment, can be economical for moulding hundreds or even tens of parts.

Requirements for the injection mold

ejection system

An ejection system is needed to eject the molded part from the cavity at the end of the molding cycle. Ejector pins built into the moving half of the mold usually accomplish this function. The cavity is divided between the two mold halves in such a way that the natural shrinkage of the molding causes the part to stick to the moving half. When the mold opens, the ejector pins push the part out of the mold cavity.

cooling system

A cooling system is required for the mold. This consists of an external pump connected to passageways in the mold, through which water is circulated to remove heat from the hot plastic. Air must be evacuated from the mold cavity as the polymer rushes in. Much of the air passes through the small ejector pin clearances in the mold. In addition, narrow air vents are often machined into the parting surface; only about 0.03 mm (0.001 in.) deep and 12 to 25 mm (0.5 to 1.0 in.) wide, these channels permit air to escape to the outside but are too small for the viscous polymer melt to flow through.

Use of plastic injection molding

Plastic injection molding is the most common and widely used method for the mass production of plastic products around the world because of its convenience and ease of use. Plastic products made using this method include plastic chairs and tables, electronic product covers, disposable spoons and knives, and other cutlery products.

History of injection molding

Plastic injection molding was started by European and American chemists who were experimenting with plastics. Originally done manually and pushed into the mold using Parkesine, it turned out to be too brittle and flammable. John Wesley Hyatt is the official inventor of plastic injection molding, and this process has a rich history with a brilliant spirit.

Injection molding was originally invented to solve the problems that billiard players face abundantly. The 19th-century billiard balls were made of ivory derived from tusks taken from elephants. Celluloid was one of the first plastics used to make billiard balls.

Plastic Injection Molding

Plastic Injection Molding

Instructions for the procedure

The scientific procedure used to produce plastic products by applying injection molding is very simple. Your plastic melts and is put into a huge syringe. It is then placed in a suitably shaped mold depending on the product being manufactured and allowed to cool for a sufficient amount of time to reach the desired shape. However, the actual process of actual injection molding is not so simple and can be broadly divided into three subdivisions: injection unit, molding section and finally clamp. The plastic pellets are gradually liquefied and gradually injected into the injection unit through a tunnel that is completely melted until it reaches the front of the barrel. When it reaches the mold, it cools and hardens to the desired fixed shape. The mold will then return to the original machine position.

All injection molded parts start with plastic pellets with a diameter of a few millimeters. They can be mixed with certain limited amounts of pigments called “colorants” or up to 15% recycled material. The mixture is then fed into an injection molding machine. Early molding units used a plunger to push down from above. However, the outer area was hot or cold and the melting process did not work properly. The solution to this was a reciprocating screw. This was often seen as the most important contribution that was none other than a revolution in the plastic product manufacturing industry. The screws cause the shear stress necessary to melt the plastic, and the rest of the heat comes from the traditional heater band that surrounds the machine. When molten plastic is injected into the mold, the air is released through the sideways vents. The honey viscosity plastic is so thick that it cannot be released from these vents, which are only a few microns wide.

Engraving witness marks on plastic products is also an important part of marketing. This is because we need to be able to authenticate and verify the authenticity of the product by looking for a line separate from the witness mark. These are created using removable inserts and can prove very helpful in tracking defects.

If you are looking for injection mould and injection molding parts?

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You are welcome to contact our technical Manager to solve your technical issue by steve@sinceretechs.com.

We have over 15 year working experience with 15 years skilled technical English communication.

Your project will be successful with our supporting, we guarantee your satisfaction.

What are you waiting for? Contact with us you will not lose anything buy have your technical issue solved.

Injection Mould China for your market

When it comes to injection mold manufacturers china, there are a number of misconceptions that people typically have. One of the biggest misconceptions is the sense that an operation that is being conducted in China is one that is largely unreliable. This cannot be further from the truth. In fact, this is an extremely reliable operation that is based in China and is turning out products that are of high quality. In order to fully understand this, it is equally important to understand the history of this type of operation as well as its current status.

Injection mold china

Injection mold china

What makes this particular operation better than those that have come before it? In the past, the the hallmark of operations of this type were that quality was sometimes not consistent and sometimes quality barely existed at all. This is especially true of some of the operations that were conducted in China. As a result, people started to have their fair share of doubts about whether or not plastic mould injection operations within the country of China could produce products of reasonable quality. Fast forward to today and those questions have been answered.

In truth, today’s operation is quite reliable and very successful. The reliability issues have been successfully put aside and any questions about quality have them put to rest long ago. Today’s operation distributes products to multiple international customers and is able to produce virtually any type of moulded plastic product for any use. The entire system utilizes a state of the art process, using the latest software to design the products that are ordered and then mass produce them as quickly and efficiently as possible. All of this is done without compromising quality in any way, shape or form.

The best part about it all is that the mistakes that were made throughout the early history of such operations has been taken into account in order to ensure that those types of issues do not happen when products are produced today. In fact, there are more than 15 years worth of operations from which to gain experience and perfect the way that everything is handled ranging from the way that orders are taken to the way that they are produced and shipped out. The fact that software is used to create virtually any type of product minimizes the chances for errors and allows everything to move along very rapidly. The end result is that the only limitation on the types of products that can be produced is the imagination of the individual who is ordering the product in the first place.

In addition, each product gets its own project manager and everything can be produced at a cost that is more than reasonable. This helps to proliferate these types of operations and even though the system is based in China, high quality products are produced each and every day which are then shipped out to locations all over the world. Imagine virtually any plastic mold part such as those parts used for calculators, DVD players or printers, and they can probably be traced directly back to operations of this type. Without them, it would be virtually impossible to operate in the world the way it is understood today.

Why Choose China Plastic Injection Molding Service?

China is well known as a manufacturing center and as an exporter of plastic products. Chinese plastic injection molding manufacturers guarantee high-quality products that are reliable and long-lasting, there are many plastic molding companies in China, it is a headache for you to find a right China mold maker from that huge resource, Sincere Tech is one of the top ten best plastic mold and molding companies in China, we offer you the 100% satisfied quality and service, go to our home page by https://plasticmold.net/ to know more.

All of the information we referred from Wikipedia, but we sort out together for easy to read, if you want to know more, please go to injection mold Wikipedia.

If you want to know more information about products made from injection mold china company? You are welcome go to our home page to know more, or send us email,we will reply you with 24 hours.

 

Molding Flash or burrs

Cold Runner Mold: Plastic Injection Molding, Simple Part Design, Limited Production Runs, Low Maintenance, Change Production Color, Low-Cost Mold

What is cold runner mold

A cold runner mold is a type of injection molding tool where the plastic material is cooled in a separate channel or “runner” before it reaches the individual cavities of the mold. The plastic resin is injected into the cold runner system, where it solidifies before being directed into the cavities to form the final parts. The term “cold” refers to the fact that the runner system is not heated, unlike a “hot runner” mold. Cold runner molds are often used for producing large numbers of small, simple parts and are relatively low-cost to produce.

SINCERE TECH (plasticmold.net) provides plastic injection mold solutions to industries of all types and sizes.

Our state-of-the-art mold building facilities include high-speed CNC Milling and mirror EDM Machining for many types of complex specialty injection molds, including insert molds, gas-assist injection molding, 2K mold, multiple cavities mold and unscrewing molds. We can build molds from small to big (25 ton) for both hot runner mold systems and cold runner mold systems.

Cold Runner Molds: Efficient and Economical

Here are some key characteristics and considerations of cold runner molds:

  1. Runner System: In a cold runner mold, the plastic material is injected into a runner system that distributes the molten plastic to multiple mold cavities. The runner system is typically designed to be easily removed from the finished part, but it generates waste material (the runners) that needs to be recycled or disposed of.
  2. Simplicity: Cold runner molds are simpler and less expensive than hot runner molds because they do not require the complex heating and control systems associated with hot runners.
  3. Material Waste: The main drawback of cold runner molds is the generation of material waste. The runners are typically discarded or recycled, which can add to material costs.
  4. Cycle Time: Cold runner molds may have slightly longer cycle times compared to hot runner molds because the plastic in the runners must cool and solidify before the parts can be ejected.
  5. Part Quality: The simplicity of cold runner molds can make them a good choice for parts with relatively simple geometries. However, in some cases, cold runners can cause aesthetic defects like visible weld lines on the finished parts.
  6. Heat-sensitive Materials: Cold runner molds are suitable for a wide range of plastics but may be less suitable for heat-sensitive materials that can degrade during the cooling process.
  7. Maintenance: Maintenance and cleaning of cold runner systems are generally easier compared to hot runners because there are no heated components to deal with.

Ultimately, the choice between cold runner and hot runner molds depends on the specific requirements of the molding project, such as part complexity, material selection, production volume, and cost considerations. Cold runner molds are commonly used in many applications, particularly when cost and simplicity are important factors.

Choosing the correct system depends on the requirements of the part to be produced. A few of the considerations include:Cold runner mold

  • Part complexity
  • Color requirements
  • Physical characteristics of the material
  • Type of material – virgin or “regrind”
  • Color changes during the production run

Cold runner systems are best used:

  • When the parts produced are of simple design,
  • For limited production runs, or
  • When a rapid change in production colour is needed

In a cold runner mold, the runner (excess material retained in the feed channels) is cooled and ejected with the part. Every cycle, apart, and a runner is produced.

There are two major types of cold runner molds:

  • A two-plate cold runner mold is the easiest and least expensive type of mold to produce. Two plate molds have a single parting plane, and the mold splits into two halves at the plane. Because the runner system must be in line with the parting plane, the part can only be gated on its perimeter.
  • A three-plate cold runner mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. This feature provides greater flexibility of design, allowing gating to be placed in the most efficient locations. Since the mold has two parting planes, the runner system can be located on one, and the part on the other, for easier separation.

Cold Runner Mold Systems: The advantages & disadvantages

There are many significant advantages to using a cold runner mold system:

  • Simple, lower-cost mold design and construction
  • Considerably less expensive than a hot runner system
  • Moulds require less maintenance
  • Easier to set up and operate
  • Colour changes are easy – all plastic in the mould is ejected with each cycle

While it is a less expensive process that hot runner systems, there are a few disadvantages to cold runner systems that need to be considered, including:

  • Waste plastic generated
  • Runner material must be either disposed of or
    reground and reprocessed
  • Additional steps in the manufacturing process
  • Regrind will increase variations in the injection 
    molding process
  • Regrinding could decrease the plastic’s strength characteristics and mechanical properties

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 your preferred plastic mold maker 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 today and experience our relentless pursuit of excellence, as we work together to bring your vision to reality.

Our expanded capabilities include:

  1. Rapid Prototyping: We offer rapid prototyping services to quickly transform your concepts into tangible prototypes, allowing for iterative design improvements and accelerated product development.
  2. Precision Tooling: Our advanced tooling capabilities enable us to create high-quality molds with tight tolerances, ensuring consistency and precision in your injection-molded products.
  3. Overmolding: We specialize in overmolding, which allows for the combination of multiple materials or components, resulting in enhanced functionality, aesthetics, and durability.
  4. Insert Molding: Our expertise in insert molding enables us to securely encapsulate inserts within the molded parts, facilitating efficient assembly and enhancing product performance.
  5. Two-Shot Molding: With two-shot molding, we can produce complex, multi-material components in a single operation, reducing assembly requirements and enhancing design possibilities.
  6. Value-Added Services: In addition to injection molding, we offer a range of value-added services, including product assembly, packaging, and logistics support, streamlining your supply chain and reducing costs.

Partner with Sincere Tech Mould suppliers for your custom injection molding needs, 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.

hot runner with manifold

What is hot runner mold

Hot runner mold is a type of injection molding system that uses heated material feed channels, or “hot runners,” to maintain the temperature of the plastics as it flows through the injection mold. This allows for a more consistent and efficient molding process, as the plastic does not have to be reheated between shots so the cycle time will be reduced and will save the waste runner materials ( sometimes has no any runner with hot runner systems). Hot runner systems are commonly used in the production of large quantities of plastic parts, such as in the automotive and consumer goods industries, or used in the stack mold.

DONGGUAN SINCERE TECH CO.LTD(SINCERE TECH) provides plastic injection mould solutions to industries of all types and sizes. For almost 20 years DST has designed, built, and worked on almost every type of mold existing in the plastic industry.

We are experienced in building custom plastic molds for a variety of hot runner mold systems, from hot runner manufacturers like:

  • Husky hot runner systems
  • Synventive hot runner systems
  • Kona hot runner systems
  • DME hot runner systems
  • Mold-Masters hot runner systems
  • INCOE hot runner systems
  • HOSCO hot runner systems

Our state-of-the-art mold building facilities include High precision CNC machines, automatic CMM measurement machine, and Two heads of EDM Machines to create many types of custom molds, including complex specialty injection molds, insert molds, unscrewing molds, overmolding, hot runner mold, cold runner mold, stack mold, gas-assisted injection molds, double injection molds (2k molding), etc. We can build molds for both cold runner systems and hot runner systems.

Hot Runner Molding: Efficient High Production

Here are some key characteristics and advantages of hot runner molds:

  1. Runner System: In a hot runner mold, the runner channels are heated, allowing the molten plastic to flow freely from the injection unit to the mold cavities without solidifying. This eliminates the need for a separate runner system, which is typically discarded or recycled in cold runner systems.
  2. Material Efficiency: Hot runner molds are more material-efficient because there is no waste generated from runners. This can result in cost savings for materials, especially for high-volume production.
  3. Reduced Cycle Time: Hot runner molds often have shorter cycle times compared to cold runner molds because there is no need for the plastic to cool and solidify in the runner channels.
  4. Improved Part Quality: Hot runner systems can help produce high-quality plastic parts with minimal defects, such as weld lines, since the plastic enters the cavities in a fully molten state.
  5. Complex Geometries: Hot runner molds are well-suited for parts with complex and intricate geometries, as they allow precise control over the flow of molten plastic to different areas of the mold.
  6. Material Compatibility: Hot runner systems are compatible with a wide range of plastic materials, including heat-sensitive polymers that may not be suitable for cold runner molds.
  7. Temperature Control: Hot runner systems require more sophisticated temperature control systems to maintain the desired temperature in the runner channels and nozzles, which can add complexity and cost to the mold design.
  8. Maintenance: Maintenance of hot runner systems can be more complex than that of cold runners due to the presence of heated components.

Hot runner molds are commonly used in industries where high precision, minimal material waste, and fast production are critical, such as automotive, medical, and consumer goods manufacturing. The choice between hot runner and cold runner molds depends on the specific requirements of the molding project, production volume, part complexity, and material selection.

Choosing the system to employ depends on the requirements of the part to be produced. A few of the considerations include:

Hot runner mold structure

Hot runner mold structure

  • Type of material to use – virgin or “regrind”
  • Colour changes during the production run
  • Single or multiple design production
  • Part complexity
  • Colour requirements
  • Physical characteristics of the material

The primary difference between the two systems is that the hot runner eliminates the excess material retained in the feed channels of a cold runner mold. This feature reduces the number of production steps required and saves in material and energy costs.

Furthermore, mostly hot runners use 100% virgin resins; no reprocessed or “re-grind” material is added. This is an important feature for specific applications where regrinding can cause the material to yellow, or detracts from the material properties, such as clarity in light pipe or lens production, where long-lasting transparency is a specific requirement.

Hot runner molding systems normally inject melted material directly into the individual mold cavity. Hot runner is almost always used for large volume production of thermoplastic injection molded parts, or multiple part production using multi-cavity molds and stack-molding technology.

Hot runner molds are two plate molds with a heated runner system inside one half of the mold. A hot runner system is divided into two parts:

  • The manifold has channels that convey the plastic on a single plane, parallel to the parting line, to a point above the cavity
  • The drops, situated perpendicular to the manifold, convey the plastic from the manifold to the part

Hot-Runner Systems: The advantages and disadvantages

Primary advantages of hot runner systems include:

  • Shorter, faster cycle times – most of them have no runners to cool
  • Smaller machines – reduced shot volume into runners
  • Automated processing – runners do not need to be separated from the parts
  • Gates at the best position for economical design
  • Elimination of runners means
  • Materials cost savings – no runner to regrind or reprocess
  • Least expensive cost/piece
  • Reduction of energy costs
  • No runners to remove or regrind
  • Reduces the possibility of contamination
  • Lower injection pressures
  • Lower clamping pressure
  • Consistent heat within the cavity
  • Shorter cooling time
  • Shot size reduced
  • Cleaner molding process
  • Eliminates nozzle freeze

Disadvantages to hot runner mold systems that need to be considered:

  • Hot runner molds are more complex and expensive to build than cold runner molds
  • Higher initial start-up costs than for cold runner systems
  • Complex initial setup prior to running the mold
  • Higher maintenance costs – more susceptible to:
    • Breakdowns
    • Leakage
    • Heating element failure
    • Wear caused by filled materials
  • Risk of thermal damage to sensitive materials
  • Elaborate temperature control required
  • The colors change is more complex than the cold runner, sometime you will spend lots of time and cost to clean up the hot runner systems, especially for transparency and white color parts.

Hot Runner Molds: Applications & Possibilities

Hot-runner systems are almost always used when large runs have to be manufactured in highly automated production. Additionally, technological advances enable us to build molds with gates positioned to yield the best quality molded parts.

Hot runner molds are sometimes connected to needle valve nozzles, which are activated with precise computer-controlled timing. This allows for a number of advanced processes, including:

  • In-Mold Decoration – lamination with a colored film coating
  • Multi-Cavity Molds – cavities with different geometries and/or volumes
    • Parts that belong together produced in one mold
    • Injection valve opening and closing can be adjusted to the conditions of each individual cavity
    • Injection pressure and holding pressure may be adjusted  independently of each other
  • Controlled Volume Balancing – a weld line can be shifted into a non-critical area of the molded part
  • Stack Molding – two or more mold bases in production simultaneously creating multiple parting lines

Partner with Sincere Tech Mould suppliers for your custom injection molding needs, 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.

plastic mold

You need to know how to fix the mold issue, plastic Mold Maintenance, plastic mold repairing, if you are running plastic injection moulding company, mold Maintenance in important.

Mould, indispensable in modern industry development and technological level improvement, is one kind of widely-used process equipment during mid-period of industrial production. According to statistics, moulding accounts for 75% of rough machining of industrial parts and 50% of precision machining. Mould can be classified as cold-punching mold, injection mold (or plastic injection mold), die casting mold, rubber mold and so on.plastic mold

1. Introduction of Injection Mould

1.1 Range of Application:

Injection mould is suitable for thermoplastic like ABS, PP, PC, POM, etc. while rubber mould is fit for thermosetting plastic, such as phenolic plastic, epoxy plastic and so on.

1.1.1 Classification of Injection Mould:

By structure: two-plate mould, three-plate mould

By gate type: edge gate mould, pin gate mould, hot runner mold

1.1.2 Structure of Injection Mould

A. Molding parts/components: normally called as cavity and core, which are the closest part with plastic products.

B. Feeding/casting system: Runner for molten plastic to flow from nozzle to cavity. It is classified as the main runner, sub-runner, runner gate, cold slag well, etc.

C. Leading/Guiding system: The system, determining the relative position of cavity and core during clamping/mold closing, is normally made up by guide pin and guide bushing. the ejector plates also need positioning by guide pin and guide bushing.

D. Demoulding structure: It is the structure ejecting the plastic part from the mold. Commonly, it consists of ejector pin, ejector plate/stripper plate, ejector sleeve, etc.

E. Temperature conditioning system: Cooling water must installed at both cavity and core site to meet the requirement of mold temperature during the injection molding process.

F. Side parting line and side action: Slide should be adopted when there is under-cut structure on the product design, i.e. the structure inconsonant with demoulding direction. It is usually made up by slide, lifter, loose core, etc.

G. Venting system: It consists of two forms: the venting groove and gap between mould components. In order to discharge air in cavity and gas caused in moulding process, venting groove is usually set at parting line, with the principle of designing venting groove as big as possible in compliance with smooth overflow and flashing. Meanwhile, insert pin, ejector pin and mould insert discharge air through gaps between mold components.

plastic mold manufacturer

2. Plastic Mould Repair

Mould repair is needed during occasions of normal or abnormal abrasion and various abnormal phenomena occurred during plastic molding production.

2.1 Preparations for moldmaster (moldmaker)

A. Make it clear the mould is damaged to what extent;

B. Develop a repair plan according to the damaged molding sample.

C. Precise understanding for repair work needed to be done: Mould repair is usually carried out without drawing with the principle of no change of the plastic parts structure and dimension. Therefore, it is prerequisite for our technician to understand precisely where and to what size should the part be repaired.

2.2 The Dos and Donts during assembly and Disassembly Mould

A. Sign mark: The corresponding sign mark in mould base must be remembered clearly when removing guide pin, ejector sleeve, ejector pin, mould insert, holder block, etc, to assure the right re-installation for the mould, especially for those with direction requirements. The following two items should be paid attention to in this process:

  • The signed mark is the exclusive one without duplication;
  • Sign mark should be made on each mould insert accordingly

B. Anti-Damage proofing: Anti-Damage proofing should be carried out for parts easy to install. In other words, parts cannot be installed back with Incorrect installation;

C. Placement: Parts removed should be placed in order while screws, springs, O-ring should be stored in the plastic box.

D. Protection: Protection measures should be made for precision parts such as mould core, cavity and so on, to avoid careless damage by people.

2.3 The Dos and Donts when Repairing Mould texture surface

A. Polishing: Protection measures for texture surface component should be made prior to repair work when polishing is needed for plastic parts with mould sticking and scrapes. It is forbidden to polish texture surface area. Mould shutoff repair should be done if it is unsure for the repair result.

B. Welding line: The following items should be paid attention to during welding on texture surface:

  • Welding rod material should be consistent with that of mould core;
  • Tempering should be done after welding;

C. Re-texture: When mould repair is finished and ready to take it out for re-texture, moldmaker should make good protection of texture area covered with paper, mark position to make texture area and attach texture template with the mould. After mould texturing, moldmaker should examine textured surface carefully to guarantee good quality and then install mould back.

If it is not sure about the repairing result, mold test should be made first. If it is OK, then take mould out to make the texture

3. Plastic Mold Maintenance

Plastic Mold maintenance is more important than mould repair. The more frequently repaired, the shorter the molds life would last. And vice versa.

3.1 The necessity for Mould Maintenance

  • Keep normal movement of the mould and avoid unnecessary abrasion of moving parts;
  • Maintain the mould to normal service lifetime;
  • Reduce oil contamination during production.

3.2 Classification of Mould Maintenance

  • Routine maintenance for the mould;
  • Scheduled maintenance for the mould;
  • Appearance maintenance for the mould.

3.3 Items for Plastic Mould Maintenance

a. Routine maintenance:

  • Oil filling on moving parts like ejector pin, slide, leader pin and ejector sleeve;
  • Mould surface cleaning;plastic mold maintenance
  • Cooling channel dredging;

b. Scheduled maintenance, following the above items;

  • Venting slot cleaning. Add venting slot at air trapping places and position burnt mark area;
  • Repair of damaged and wearing places;

c. Appearance maintenance:

  • Make painting for outside of mould base to avoid rusting;
  • The cavity should be coated with anti-rusting oil/grease after mould dropping/shutoff.
  • Mould should be closed tightly for storage to avoid dust coming into mould core.

3.4 The Dos and Donts for Mould Maintenance

a. For moving parts, oil filling during routine maintenance is necessary;

b. Mould surface must be clean enough: Tag paper cannot be stuck on P/L side. Do not close the mold when molding part is sticking to the cavity or core side, clean the plastic residues at P/L position.

c. Abnormal condition identification, Prompt repair should be made if there is ejection abnormity, great noise during mold-opening and mold-closing.

4. Safety Issues during Mould Repair and Maintenance

Safety should be put in the first place whenever and wherever. Mould repair and maintenance, with close contact with mold machine and steel equipment, is no exception. It is necessary to pay high attention to safety issues during this process.

  • Examine carefully before use to make the sure hanging ring in perfect condition.
  • The worker must wear safety goggle when operating mold machine to avoid flying chip into eyes
  • The worker must wear protective clothing and safety goggle during the welding process.
  • It is forbidden to operate at the bottom of the mould.
  • Injection moulding machine must be in stopped state and nameplate should be hung on it before operating machine.
plastic cup mold

How To Save Injection Molding Cost By Multiple Cavity Mold

When you have a project, then you may need plastic injection molded parts. The first thing you need to do is find a plastic mold company to make mold & molded parts, but before starting this, I think you need to check injection molding cost and mold cost in advance for your investment budget. Multi-cavity injection molding will be one of the best ways to save unit production cost.

Like other things, there is no one solution that is suitable for all of the projects. Below are some suggestions on how to save injection molding cost. There are both advantages and disadvantages; by reading this, you could choose the one based on your project requirements.

What is multi cavity injection molding

Multi-cavity injection molding is typically used when high-volume production of identical parts is needed. It allows for the efficient production of multiple parts in a single cycle, which can significantly increase production rates and reduce the cost per part. Additionally, using a multi-cavity mold can also help to reduce the overall cost of the mold itself.

Multiple cavity mold means the number of cavities greater than one, which means that it has more than one part in an injection mold. It is usually professional to say cavity, One cavity or two cavities, for example, 8 cavity mold, means one molding cycle to mold 8 parts with the 99% same part feature, dimension, shape, size, etc.

Some examples of products that may be produced using multi-cavity injection molding include automotive parts, electronic components, toys, and household items. It is also commonly used in the production of medical devices, personal care products, and packaging.

multiple cavity mold

24 multiple cavity mold

When do we need Multiple Cavity Mold?

There are some factors to consider before starting to make your plastic mold.
1, the size of the plasatic product,
2. The number of the plastic products requirement
3. The size of the machine; if you only buy plastic molded parts, then you do not need to care about this point; your plastic molding supplier will handle this for you.

If the size of the product is small, such as the computer keyboard button, usually make 24 or 48 Multiple Cavity Mold, you must say why not make 30 or 40? This is because of the balance mold layout and material filling balance, especially when you use cold runner mold. So normally multi-cavity mold is 4, 8, 16, 24, 48, and 96 cavities are better options.

When we make multiple cavity mold and the cavities are more than 24, we normally suggest making hot runner mold, one part per hot drop. Of course, this will be a high cost for the injection mold. In that case, we suggest at least using six hot runners transferring to the cold runner, which means four cavities per hot drop. This could save the cycle time and keep the best quality of injection molding parts.

The advantages of Multiple Cavity Mold

The reason we make multi-cavity molds is simple: we need to save production unit cost for each plastic molded part. Multi-cavity molds have several advantages over single-cavity molds in injection molding:

  1. Increased production efficiency: By producing multiple identical parts in a single cycle, Multiple Cavity Mold can significantly increase production rates and reduce the overall production time.
  2. Reduced cost per part: Multiple cavity molds can produce multiple identical parts at a lower cost per part than single cavity molds.
  3. Reduced tooling costs: Since multi-cavity molds require only one tool, the overall cost of the mold is typically lower than that of multiple single-cavity molds.
  4. Better consistency: By producing multiple identical parts in a single cycle, multi-cavity molds can improve the consistency of the final product, reducing the need for rework or scrap.
  5. Reduced labor costs: Multi-cavity molds require less labor to operate than multiple single-cavity molds, as the operator only needs to monitor one machine.
  6. Reduced material consumption: By producing multiple parts in a single cycle, multi-cavity molds can also reduce the amount of raw material required to produce the final product.
  7. Improve part quality: Due to the consistency in the process and the precision of the machinery, multi-cavity molds can produce parts with tighter tolerances and a better surface finish.

The disadvantages of multi cavity mold

We all know that all of the customers prefer the multiple cavity mold since this can save lots of production cost, but there are other factors you need to think about before making a decision, because making plastic mold is not cheaper; making multi-cavity mold is more expensive than single cavity mold, sometimes double or even three times more expensive than single cavity or two-cavity mold.

For example, if you make 24 cavity mold, then you at least need 6 hot runner drops for the mold; the pure hot runner cost is around USD 5400 (YUDO brand); if you use a China local brand of hot runner, you still need USD 3000, and this cost some times is enough to make 2 cavities of cold runner mold. Since there are many cavities in one mold, the mold manufacturing cost is higher than the less cavity mold as well; this is another cost, so the total cost is two or three times more.

  1. Higher initial cost: The initial cost of a multi-cavity mold can be higher than that of a single cavity mold, especially for complex designs.
  2. Greater complexity: Multi-cavity molds are more complex than single-cavity molds and require more precise machining and design. This can lead to longer lead times for tooling and an increased risk of defects.
  3. Higher maintenance costs: Due to the complexity of the mold and the increased number of moving parts, multi-cavity molds may require more maintenance and repairs than single-cavity molds.
  4. Greater risk of defects: With multiple cavities, the risk of defects is greater, as a problem in one cavity can affect multiple parts.
  5. Increased cycle time: Multi-cavity molds have longer cycle times than single-cavity molds as the machine has to fill multiple cavities at once.
  6. Greater potential for warpage: multi-cavity molds have to be designed to account for the potential warpage that can occur during the cooling phase of the injection molding process.
  7. Increased risk of sink marks: As the material cools, it will shrink. If the mold design is not optimized for multi-cavity, sink marks may appear on the surface of the parts.
  8. Increased risk of flash: flash is the excess material that is extruded from the mold. Multi-cavity molds can be more prone to flash than single-cavity molds, as the pressure and flow rate of the material are increased to fill multiple cavities.

injection molding wall thickness

When do you need multiple cavity mold

There is some simple suggestion: when do you need to make single cavity mold (may have 2 cavities at the fist) and when should you make multi-cavity mold, like 8 cavity mold, 16 cavity mold, or more? When you are sure that you will need the plastic parts more than one million or at least 0.5 million, then going to 8 or more mold cavities will surely save cost for you.

You may need to pay more for plastic mold manufacturing, but compared to the production cost you are going to save, this injection mold cost is insignificant because you will save 10 times more than this injection mold cost.

If you are not sure how many plastic molding parts are needed at the first, or if this is depending on your business market, then we suggest using the 2 cavity mold at first, because this can save the plastic mold cost for you in advance. After you open your market and the requirement of injection molded parts increases, you can still save injection molding cost by making new multiple cavity mold.

You use the existing mold to produce the parts at the same time and make a new multi-cavity mold; this will not have a delay as well. After the multiple cavity mold is finished, you only need to run this multi-cavity mold, but if the quantity requirements are not so high, then you use the current molds to produce, so you still have good profits with less investment (compare to make multi-cavity mold at the beginning).

When do you need single cavity mold

A single-cavity mold is a type of mold used in the injection molding process. It consists of a single cavity or impression that forms the desired shape of the plastic part. This type of mold is used when the production volume is low or when the part design is complex and requires more attention to detail.

Advantages of using a single-cavity mold include:

  1. Flexibility: Single-cavity molds allow for more flexibility in terms of part design and material selection. Each cavity can be customized to meet specific requirements.
  2. Precision: With only one cavity to focus on, manufacturers can pay more attention to detail and ensure higher precision in the molding process. This is particularly important for intricate or complex part designs.
  3. Cost-effective for low volume production: Single-cavity molds are cost-effective for low volume production runs. They have lower initial tooling costs compared to multi-cavity molds and are more suitable when the production quantity is small.
  4. Material compatibility: Single-cavity molds are ideal when different materials or processes are required for each part. This allows for the production of diverse parts with varying material properties.

A single-cavity mold is typically needed when you require a small quantity of parts or when the part design is complex and requires more time and precision to manufacture. It is also used when the part size is large and cannot be accommodated in a multi-cavity mold. Additionally, a single-cavity mold may be preferred when the cost of manufacturing multiple cavities is not justifiable or when the part design requires different materials or processes for each cavity.

What do you think? By reading above, I assume you have an idea on how to save injection molding costs for your project.

If you have any project in hand that needs to make injection mold for your business, you are welcome to contact us. We will give you some good suggestions and ideas to help you spend minimum investment on plastic mold cost and open your market rapidly.

Sincere Tech is one of the top 10 mold manufacturers in China and offers custom plastic molds, injection molding manufacturing, die casting,prototypese, machining, and many moreservices.  As one of the best injection mold suppliers in China, we pride ourselves on our commitment to excellence.

Below are a few of the services we offer:

  1. Rapid Prototyping: We offer rapid prototyping services to quickly transform your concepts into live parts, allowing for iterative design improvements and accelerated product development. Please go to the rapid prototyping service page to know more.
  2. Precision CNC Machining: Our advanced tooling equipment enables us to make high-quality plastic molds and machining components with tight tolerances, ensuring consistency and precision in your injection-molded products. Please go to the precision CNC machining page to know more.
  3. Overmolding: We specialize in overmolding, which allows for the combination of multiple materials or components, resulting in enhanced functionality, aesthetics, and durability.
  4. Insert Molding: Our expertise in insert molding enables us to securely encapsulate inserts within the molded parts, facilitating efficient assembly and enhancing product performance.
  5. Two-Shot Molding: With two-shot molding, we can produce complex, multi-material components in a single operation, reducing assembly requirements and enhancing design possibilities.
  6. Value-Added Services: In addition to injection molding, we offer a range of value-added services, including product assembly, packaging, and logistics support, streamlining your supply chain and reducing costs.
  7. Product assembly Service: We offer all in one service from part design, production, until delivery, if you need products assembly service in China, we will be one the best options for you.

Not limited to below but more services we offer, welcome to contact us for your custom injection molding needs (no matter multiple cavity mold or single cavity mold).

plastic injection mold

Looking for plastic injection molding service?

Contact us to get quote, we are A Custom injection mold maker in China that offers plastic injection molding services.

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 injection molding service

plastic molding services

Benefits of plastic injection molding service

The benefits of plastic injection molding service include:

  1. High volume production: Plastic injection molding is ideal for high volume production of identical parts, as the mold can be used multiple times.
  2. Consistent quality: The process is highly repeatable, which leads to consistent quality of parts produced.
  3. Complex shapes: Plastic injection molding can produce complex and intricate shapes that would be difficult or impossible to achieve with other manufacturing methods.
  4. Material flexibility: A wide variety of plastic materials can be used in the injection molding process, including thermoplastics, thermosets, and elastomers.
  5. 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.
  6. Precision: The process can produce parts with high dimensional accuracy and minimal tolerance variation.
  7. 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.Plastic Injection Molding Service

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

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.