What is Injection Molding?

In modern manufacturing, Molding is one of the core techniques for shaping product shape. As the most influential process, injection molding has become the preferred solution for plastics production with its high efficiency, high accuracy and wide adaptability. By injecting molding high-pressure molten plastic or liquid silicone into the mold cavity, giving the product precise dimensions and complex structure,truly embodies the significance of molding meaning——transforming raw materials into practical, aesthetically pleasing, and economical products.

JS, as leading company in the industry, has been deeply involved in plastic molding for more than 20 years. Whether it's optimizing molding design to reduce production costs or choosing silicone molding materials to improve product performance to meet specific needs, JS drives manufacturing upgrades with technological innovation to help customers stand out in a competitive market.

The processing process of injection molding

What is injection molding?

Injection molding is an efficient manufacturing technique in which granular or liquid plastic/rubber materials are heated and melted, injected into mold cavity under high pressure,cooled and solidified into various plastic moldings. Widely used in auto parts, medical devices, consumer electronics and other fields. It has the advantages of high precision and large production scale, and has become the core technology of modern plastic processing.

What is injection molding?

What are the core advantages of injection molding?

1.Efficient mass production, fast delivery

Molding injection technology involves injecting molten material into molds at high temperature and pressure, producing hundreds of thousands to thousands of plastic moldings at a time. It is particularly suitable for mass production and significantly shortens delivery cycles.

2.The structure is precise and complicated, and the labor cost is reduced

From micrometer level precision parts to complex components embedded in parts and surfaces,moldinginjection technology relies on die precision (±0.01mm) to meet design requirements, eliminating the need for secondary processing and reducing manual intervention and material waste.

3.Flexible material selection of materials to meet diverse needs

Supports injection-molding of thermoplastics (such as ABS, PC), thermosetting resins, liquid silicone, and various other materials.It can be customized with special properties such as abrasion resistance, temperature resistance, and biocompatibility to meet the needs of high-end areas such as healthcare and consumer electronics.

What are the core elements of injection molding design?

Plastic Mold Design is the key to the success of plastics molding. It is necessary to consider the mold structure, material selection and process parameters:

Core elements	Key content
Mold structure	Number of mold cavities: 1 to more molds,depending on yield. Distance between cooling channels: ≥15mm (to avoid heat stress).
Material selection	Plastics: PET (shrinkage 0.8%~1.2%), PA6 (shrinkage rate 1.0%~1.5%). Liquidity: PETG 40-60g/10min.
Process parameters	Injection pressure: PET 80~150MPa, hard PC 100-300 MPa. Barrel temperature: ABS 80~95 °C, PPO 260-280 °C. Pressure retention time: 0.5-3 seconds (thicker wall to be extended).
Product design optimization	Wall thickness recommendation: ≥1.2mm (thin-walled pieces must be ≥0.8mm). Towing angle: 1°~3° (up to 5° for deep pores or complex structures). R ≥ 0.5mm (to avoid stress concentration).
Quality Management	Dimensional tolerance: ± 0.1mm (precision parts)~± 0.3mm (ordinary parts). Surface defect: Ra ≤ 0.8 μm (no bubbles, burrs).

How is an injection-mold made?

1.Design planning: Precision matching

The design of injection molds shall be in accordance with the characteristics of product drawings andmoldingplastic materials. JS engineers use CAD software to complete molding plastic designs, ensure uniform wall thickness (1-4mm), reasonable draft angle (1-3°), and optimize gate position to reduce shrinkage marks. JS company, for example,focuses on the characteristics of liquid silicone with a 0.02mm thin-walled design and specializes in precision components such as medical catheters.

2.Material selection: Adaptation process and costs

Mold steel shall be selected according to the type ofmoldingplastic in the die:

Thermoplastic plastics (e.g. ABS,PC): P20 or SKD11 steel, high temperature resistance, high hardness.
Liquid silicone: Made from H13 steel, it is corrosion resistant and has a smooth finish, reducing the risk of silicone sticking to molds.
JS extended the service life of the die by over 30% by using JSR specialized mold steel.

3.Processing and manufacturing: High precision molding

Rough machining: The main contours are completed by numerical control CNC machin.
Precision machining: Slow line cutting with accuracy ±0.005mm.
Surface treatment: For transparent plastic molds, polish to Ra<0.05 μm to remove burrs.
JS company has 4000T level large CNC equipment to support complex inserts and multi-cavity molds for integrated processing.

4.Assembly and debugging: Verify functionality

Die core assembly: Accurate insertion of slider and ejection mechanism to ensure synchronous movement.
Test molds: Inject molding plastic raw materia, verification of molding cycle (e.g. 20-60 seconds/piece) and product size tolerance.
Problem correction: Adjust the exhaust groove or cooling water circuit according to the trial mold results, and optimize the warping and bubble defects.

5. Maintenance and upgrading: Extend Service Life

Periodic maintenance: Cleaning mold cooling water circuit of the scale, repair polished surface.
Intelligent modification: Install temperature sensors and IoT module to monitor mold status in real time.
Rapid mold change: For multi-variety production, adopt rapid molding insert design,reduce mold change time to less than 15 minutes.
JS company provides lifetime warranty for molds,supports remote diagnosis and rapid maintenance.

Injection molding molds

What key indicators should be considered in material selection for injection molding?

In injection molding, the choice of material directly affects the performance, production efficiency and cost of the product.The following are key indicators to consider and JS company's technical practice suggestions in the field of plastic molding:

1.Mobility

The flowability of the material determines its efficiency in injection molding.High-mobility materials (such as liquid silicone JSR) tend to fill complex structures but can cause burrs,low-mobility materials (such as high-density polyethylene (HDPE)) require high injection pressure.
JS ensures the stability of the injection molding process by optimizing material formulation and mold design,such as adding exhaust slots,and is particularly adept at handling thin-walled components of low fluidity materials,such as medical catheters.

2.Shrinkage rate

The shrinkage rate of the material after cooling and curing directly influences the dimension accuracy.Liquid silicone gel shrinkage rate of only 0.1-0.3% and is suitable for high precision medical devices.
JS company compensates for shrinkage through mold design and controls product size tolerance to ±0.05mm.

3.Thermal stability

The material is subjected to high injection molding temperatures (e.g. 280 °C for PET).JS is equipped with high temperature injection molding machines (up to 400 °C) that support the processing of high temperature resistant resins (e.g. POM, ASA) and predict the risk of thermal degradation to avoid warping or discoloration.

4.Mechanical properties

Tensile strength: Engineering plastics (such as PCs) can reach up to 60MPa for automotive components. liquid silicone has a tensile rate of over 300% for flexible seals.
Shock resistance: TPU material are reinforced with fiberglass (e.g. PA66 + GF30) to increase their impact resistance by 50%, making them suitable for fragile items such as mobile phone cases.

5.Cost and recoverability

Low-cost materials: ABS and PS for mass production.
Environmentally friendly materials: (polylactic acid and PCR recycled materials can reduce carbon emissions by more than 30%. JS promotes injection molding using recyclable materials to help customers achieve carbon neutrality goals.

Material selection for injection molding

How to optimize product structure and production efficiency through injection molding design?

Structural design optimization

1.Wall thickness uniformity design: CAE flow analysis used to optimize wall thickness distribution and avoid shrinkage marks and stress concentration. For example, optimising wall thickness from 3mm to 2.5mm can shorten cooling time by 30%. For complex components, thicken them with rib structures rather than solids.

2.Demoulding slope and draining design: Recommended internal and external draining angles ≥0.5°. Gradual conduction is used in the deep cavity structure to reduce demoulding resistance. JS company's precision EDM discharge machining can handle sharp edges of up to 0.02mm.

3.Optimization of pouring system: Adopt heat flow system (JS company support needle valve hot nozzle structure), reduce gate residue,improve yield. For example, using invisible doors in car interiors can reduce burrs by up to 40%.

process parameters optimization

1.Dynamic control of holding pressure curve: JS company's closed-loop control system is used to control holding pressure in real time.

2.Cooling system optimization: According to the analysis of the die flow of JS company's mold flow, a conformal cooling water circuit is designed to shorten the cooling time by 20%-30%.The display period of a car component shell has been reduced from 45 seconds to 32 seconds.

What are the key application areas of JS injection molding?

1.Automotive industry

Purpose: Lightweight design for bumper, panel, engine components, etc.
JS case: Customized battery cover plates for new energy vehicle companies, reducing warpage rate from 8% to 1.2% by optimizing gate layout, saving more than $1 million annually.

2.Consumer electronics industry

Purpose: Precision structural components such as phone case, earphones and smartwatch case.
JS case: 7-day delivery, ultra-thin phone case mold (only 0.3mm thick), support for PC+TPU dual-colour injection molding, 98% pass rate.

3.In the medical field

Purpose: Syringe barre,infusion tube accessories, heart stents, medical catheter and other high hygiene components.
JS case: A biodegradable medical suture anchor has been developed for a multinational medical device enterprise with PLA and TPU dual material injection molding with a product size tolerance of ±0.2mm to help customers capture the minimally invasive surgery market.

4.Industrial and mechanical components

Uses: Gears, bearings, sea and other wear-resistant and high-temperature components.
JS case: POM material injection molding high rigid gears instead of metal parts, reduce the cost by 30%.

What injection molding solutions does JS company have?

1.Multi material injection molding solution

By using precision die design, the combination of PC + TPU, ABS + PC can form a soft and hard bonding structure, and material utilization be increased by 30%,and the cost can be reduced significantly.
Multi cavity mold design (up to 20 cavities) balances cooling efficiency and exhaust performance.

2.Precision mold design and Manufacturing

High precision machining: Die cavity machining accuracy is ±0.005mm,supporting 0.1mm thin-walled injection molding (e.g. precision instrument housing).
Shape of cooling water circuit is as follows: 3D-printing water circuit cover complex cavities, improve cooling efficiency by 30% and achieve a warpage deformation rate of less than 0.5%.
Automated injection molding: Integrated vision positioning system, metal inserts (such as screws and chips) can be embedded with accuracy ± 0.02mm.

3.Rapid prototyping and small and medium-sized batch production

3D Printing trial mold: Resin prototypes delivered within 72 hours to expedite customized product validation.
Rapid molding system: Molding in 15 minutes, suitable for small lots of multi-variety orders.
Flexible manufacturing unit: Set injection molding, testing, packaging in one, 7 working days to complete small and medium-sized orders.

Summary

Injection molding, as the cornerstone process of modern manufacturing industry, continues to promote the innovative development of automotive, electronics and medical industries with its advantages of high efficiency,accuracy and adaptability. Suitable for precision medical catheters and lightweight automotive components, from mold design to material selection (e.g. ABS, PC, PA, etc.) and precise control of process parameters (pressure, temperature, insulation time), injection molding balances production efficiency and product performance and serves as a core bridge between design and mass production.

JS company focuses on injection-molding technology innovation, optimizing material selection, mold structure and process parameters. Whether pursuing extreme efficiency, complex structures, or green manufacturing,JS company offers customizable solutions to ensure that every plastic product has quality, value, and vitality.

Disclaimer

The content of this page is for informational purposes only.JS SeriesNo representations or warranties of any kind, express or implied, are made as to the accuracy, completeness or validity of the information. It should not be inferred that the performance parameters, geometric tolerances, specific design features,material quality and type or workmanship that the third-party supplier or manufacturer will provide through the jusheng network. This is the responsibility of the buyerAsk for a quote for partsto determine the specific requirements for these parts.please Contact us Learn more information.

JS Team

JS is an industry-leading companyFocus on custom manufacturing solutions. With over 20 years of experience serving more than 5,000 customers,we focus on high precisionCNC machining,Sheet metal fabrication,3D printing,Injection molding,metal stamping,and other one-stop manufacturing services.
Our factory is equipped with more than 100 state-of-the-art 5-axis machining centers and is ISO 9001:2015 certified. We provide fast, efficient and high-quality manufacturing solutions to customers in more than 150 countries around the world. Whether it's low-volume production or mass customization, we can meet your needs with the fastest delivery within 24 hours. chooseJS TechnologyIt means choosing efficiency, quality and professionalism.
To learn more, please visit our website:jsrpm.com

FAQs

1.How to choose injection molding and CNC machining?

Injection molding is suitable for a large quantity of complex parts. CNC is suitable for small batch,high precision or metallic materia.

2.What is the difference between silicone injection-molding and ordinary plastic injection molding molding?

Silicone requires liquid injection and vulcanization molding to make the product softer and more environmentally friendly, but at a higher cost. Ordinary plastic is melted and injected directly, then naturally cooled and molded.

3.What are the advantages of injection molding?

Production efficiency,large-scale production of shared mold costs, extremely low unit cost, high size accuracy, smooth surface, wide scope of application, suitable for large-scale production. Comprehensive cost efficiency is outstanding, is the plastic products manufacturing mass production method of choice.

4.Why does it need to be cooled during injection molding process?

After the molten plastic is injected into the mold, it needs to be cooled and solidified quickly to retain its shape for easy removal. Plastics are liquid at high temperatures and must be cooled to retain their shape inside the mold and avoid product distortion and warping. When cooled, the plastic becomes more rigid, making it easier to remove.