A Comprehensive Guide to Plastic Mold Manufacturing in China

Plastic mold manufacturing is a major industry in China. As the world’s largest producer of plastic products, China has developed extensive capabilities in plastic mold design, tooling, machining, injection molding and other plastic molding processes.

In this guide, we’ll provide a comprehensive overview of plastic mold manufacturing in China – how it works, the different types of molds, materials, applications, leading suppliers, costs and tips for sourcing high quality plastic molds from China.

What is a Plastic Mold?

A plastic mold is a custom-made tool used to shape molten plastic material into a desired shape through injection molding or other plastic molding processes. Plastic molds consist of two halves – the core side and the cavity side. When closed together under pressure, the plastic material gets injected into the mold cavity and takes its shape.

Plastic molds are made from tool steel or aluminum. The choice of material depends on factors like cost, strength, hardness and expected production run. Steel molds are more durable and suitable for high volume production. Aluminum molds are cheaper but cannot withstand as high pressures.

The mold cavity is created based on the desired shape and specifications of the final plastic part. Complex 3D shapes require advanced CNC machining capabilities. The mold also includes a dedicated system of channels, known as runners and gates, through which the molten plastic flows into the cavity.

Types of Plastic Molds

There are several types of plastic molds, classified according to the type of molding process used:

Injection Molds

Injection molds are used for injection molding, the most common plastic molding process. Injection molds are complex precision tools, built to withstand high temperature and pressure. Quality factors include uniform wall thickness, draft angles and surface finishes.

Blow Molds

Blow molds are used to shape hot plastic material into hollow shapes like bottles through blow molding. They consist of two halves and must withstand high internal pressure.

Rotational Molds

Rotational molds are used for rotomolding processes to create seamless, hollow and stress-free plastic parts. They consist of two halves which are rotated and heated during molding.

Compression and Transfer Molds

These specialized molds are used for compression molding and transfer molding processes in niche applications. They have simpler designs with two halves and minimum moving parts.

Thermoform Molds

Thermoform molds provide the shape template for thermoforming processes. They can be machined from wood, epoxy or aluminum.

Plastic Mold Manufacturing Process in China

Manufacturing high quality plastic molds involves highly-specialized skills, equipment and experience. The typical plastic mold making process in China includes:

Mold Design – Creating 3D CAD models and detailed technical drawings for the mold tooling. Advanced engineering analysis is conducted using Moldflow and other software.
CNC Programming – Converting design data into precise CNC toolpaths for machining the mold components.
Tooling & Machining – Cutting and machining blocks of tool steel or aluminum on CNC machining centers. Electrical discharge machining (EDM) creates complex cavities.
Polishing & Texturing – Polishing mold surfaces to desired finish standards using automated processes. Texturing adds custom surface effects.
Assembly & Testing – Assembling the finished mold halves and components. Testing validates mold performance before production.
Secondary Processes – Additional finishing steps like heat treatment, plating, etching and laser engraving.

The best plastic mold makers in China can produce molds with exceptional surface quality, dimensional accuracy and consistency. Automation allows high production efficiency and costs savings compared to other countries.

Plastic Mold Design Considerations

Mold designers need extensive knowledge of plastic materials, molding processes and mold fabrication techniques. Key design considerations include:

Plastic Material Properties – Flow characteristics, shrinkage, thermal expansion effects.
Part Design – Uniform wall thickness, draft angles, radii and fillets, ribbing for strength. Avoiding sinks and warpage.
Runner and Gate Design – For balanced flow and optimal mold filling pattern.
Cooling Channels – Effective cooling channel layout to reduce cycle times.
Cavity Polishing – Required surface finish standards and texture.
Mechanical Functions – Components for ejection, sliding cores, unscrewing, etc.
Standard Components – Using standardized mold bases, inserts and hot runner systems.
Automation – Designing for automation and ease of manufacturing.

Proper mold design minimizes defects like short shots, flash, warpage and improves part quality and costs.

Plastic Mold Materials Used in China

The most commonly used plastic mold materials in China are:

P20 Tool Steel – Versatile, strong and cost-effective. Heat treated to 60 HRC hardness.
718 Steel – Higher hardness of 50-55 HRC, excellent wear resistance and longevity. Used for large production runs.
S136 Steel – High hardness of 56 HRC and polishability. Used for small precision molds.
Aluminum Alloys – Softer but cheaper material for prototype molds and low volume runs.
Beryllium Copper – Specialty alloy with high thermal conductivity. Used for conformal cooling channels.
Stainless Steel – Corrosion resistant, used for molds injecting corrosive plastics.

The choice of material depends on production run sizes, mold strength needs and plastic materials being used. Pre-hardened tool steels allow faster machining while custom heat treating can achieve optimal hardness.

Plastic Mold Industry in China

China is the world’s top producer of plastic molds with an estimated market size of over $25 billion. The Pearl River Delta region, especially Guangdong province, is the heart of plastic mold manufacturing in China.

Thousands of Chinese companies offer plastic mold design, tooling, machining, finishing and assembly services. The industry ranges from small workshops to large enterprises with advanced equipment and integrated capabilities.

Key advantages of China’s plastic mold industry include:

Low Costs – Labor, raw materials and infrastructure costs are lower compared to Western regions. Highly competitive pricing.
Production Capacity – Enormous capacity with thousands of shops and skilled workforce for mass production.
Mold Materials – Readily available tool steel, aluminum alloys and standard components.
Equipment – Heavy investments in advanced CNC machines, EDM, LASER, automation and manufacturing technologies.
Specialization – Companies dedicated to specific mold types, plastic materials, industries and secondary processes.
Supply Chain – Comprehensive network of suppliers for mold components, materials, heat treatment, plating, etc.

However, quality control and intellectual property protection remain key issues to watch out for when sourcing molds in China.

Applications of Plastic Molds

Plastic molds are used to manufacture a vast range of plastic products across every industry:

Automotive – Interior and exterior components like bumpers, panels, lights, dashboards, buttons.
Consumer Goods – Appliances, electronics, furniture, sports equipment, housewares.
Medical – Diagnostic devices, disposable syringes, containers.
Packaging – Bottles, caps, boxes, bins and cases for all types of products.
Toys & Games – Action figures, building blocks, playsets molded in bright colors.
Industrial – Gears, rollers, tool housings, labels, signage, machine components.
Agriculture – Trays, pots, watering tools.

And many more. Innovative mold designs and plastic molding technology allow the mass production of affordable, functional plastic goods that are ubiquitous in modern life.

How to Source High Quality Plastic Molds from China

Here are tips for sourcing premium plastic molds from China:

Define Requirements – Specify plastic material, annual quantities, precision needs, surface finishes, secondary processing, quality standards and testing expectations.
Evaluate Suppliers – Check credentials, client reviews, in-house capabilities, certifications and experience with similar projects. Get references.
Request Prototypes – Test potential suppliers by ordering prototypes first before full production tooling.
Engineering Review – Have designer review mold drawings before machining to ensure conformance.
Production Monitoring – Schedule factory inspections and testing during mold fabrication.
IP Protection – Sign NDA and mold ownership agreements. Avoid sending full 3D CAD data.
Validation Testing – Test samples thoroughly after tooling completion before approving full mold orders.

Sourcing from established, reputable companies like JEVEN Plastics with proven design engineering and program management capabilities is recommended for consistently high quality results.

Costs of Plastic Molds from China

Plastic mold costs from China include:

Mold Design Fees – $1,000 to $5,000 depending on complexity.
Tooling Costs – $2,000 to $20,000+ depending on size, material, number of cavities, surface finishes and complexity.
Secondary Processes – $500 – $2,000 for heat treating, plating, laser etching, etc.
Production Piece Prices – Varies based on size, material, post-molding processes and order volumes. Expect $0.50 – $5 per piece.
Shipping & Logistics – Freight, duties and local delivery costs.

Typically, the mold tooling cost makes up 15-25% of the total lifetime cost for a plastic product. Rushed delivery timelines usually attract higher premiums of 20-50%. Building prototype molds first in lower cost materials can provide significant initial savings.

Conclusion

China offers a complete ecosystem for cost-effective plastic mold manufacturing. With the right design engineering, quality control measures and supply chain management, Chinese mold makers can deliver high precision, durable production molds for complex plastic products.

By leveraging China’s advantages in tooling capabilities, automation and skilled expertise while mitigating risks around IP and quality assurance, businesses around the world can benefit from sourcing plastic molds in China for their manufacturing needs.