What is Injection Molding?

Injection molding is a method of forming a product by injecting molten plastic into a mold and then cooling and solidifying it,which is suitable for mass production and complex shape products.

Shanghai Jinxi Injection Molding Services

Except CNC Machining, we also make plastic molds and injection parts both for prototyping and mass production.

Technical Support

Early involvement in customer products analysis

Design Software: UNI-GRAPHIC, Pro-E, CATIA,Auto CAD

Tolerence: CNC- 0.01mm,EDM-
0.01mm, Grinding- 0.005mm

Provide DFM & Mould Flow analysis report

Mould design and machining

Mould design and modification

Trial production

Mass production for continious orders running

Custom Molding Service

Single-cavity, multi-cavity, and family mold options

Insert Molding

Double color Molding


Press availability from 50 to 1,100+ tons

Injection Molding Materials

ABS: High impact resistance with low density,”Tough, hard, rigid, cheap”.The comprehensive performance is good and used widely in machinery, electrical, textile, automobile, aircraft, ships and other manufacturing industries and chemicals.
PA: High mechanical strength, good toughness, high tensile strength which is higher than metal and the compressive strength is close to metal. The impact strength is much higher than ordinary plastic.
PC: PC has good mechanical properties, but poor fluidity.The drying before injection is very important and the recommended drying conditions are 100C to 200C for 3 ~ 4 hours. The humidity before processing must be less than 0.02% .
PP: PP is a crystalline polymer. The density of PP is only 0.91 g/cm3(smaller than water) . In general purpose plastics, PP has the best heat resistance. and also good resistance to stress cracking and high bending fatigue life. The comprehensive properties of PP are better than those of PE.
PE: Polyethylene (PE) is the most widely used synthetic resin due to its excellent processability and serviceability
PC-ABS: The alloys of PC and ABS, PC has strong impact resistance, high heat resistance while ABS has very good toughness, so this material is better performance than a single PC or ABS and, more expensive.
POM: High crystalline polymer with high elastic modulus, high hardness and high stiffness. Can be used in-40-100 °C for a long time. It’s the most superior type among the thermoplastic material on fatigue resistance.

Injection Molds Surface Finish

We generally polish it a little with 800#sandpaper if no special requirement.

General use of stone, wool wheel or sandpaper, mainly done by manual. We can make it mirror polishing if requsted.

This texture is done by EDM Machining on the mold.

There are many types of the different texturing. and the often used here including MT11010, MT11020.

Electroplating is the process of depositing metal or alloy on the surface of a work piece by electrolysis to form a uniform, dense and well-bonded metal layer.

Sand blasting is a surface treatment of the workpiece process, using Compressed air as the power to form a high-speed jet to the surface of the mold.

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Advantages of Injection Molding

01.High Precision

The plastic molding is suitable for the complex and precise products. We can make the plastic molds with high precison +-0.02mm with our advanced machining equipment. Therefore, it is widely used in the production of automotive parts.

02. Variety Materials

A large number of plastic materials can be used for plastic injection molding process, like thermoplastic rubbers, chemical resistant plastics and bio-compostable materials that have color matching or masterbatch coloring.

03. Low Costs

Injection molding is an automated process which can be performed by machines and robots, also the labour will be reduced too. So the piece price can be decreased a lot compared with other manufacturing process.

04. High Efficiency

As soon as a mold is making, we can make the production very fast with the injection machines running 24hours automatically.

05. Low Waste

In Mass production, injection molding produces much less waste and use less resources which is friendly to environment.

06. More Strength

The injection molding parts will perform much better than those made by cnc machining or 3d printing.

Mold Design Ability

the Design and programming software we use here including UG, Solidworks, Pro/E, Mold Flow

Insert Molding and OverMolding

Insert molding is to have the metal insert pre-positioned in the mold and then injected into the plastic for molding, so that you can get a final product with an insert tightly embedded like a threaded ring,a brass nut or an electrode.

This type of molding will help to make parts all at once instead of post-assembly, especially when the inserts very small and quite a few ones on one part,it’ll save the assembly trouble a lot. also it’ll improve the product strength, since one-shot process will make the embedding very tight and easy to use.

Overmolding is actually one type of secondary injection molding which includes 2 parts,one is the main body (the hard plastic), and the other coating part (the soft one). When making molds we need to make the hard one first,and then put it into the coating mold.

The often used overmolding plastics as below

main body: ABS, GPPS, HIPS (475) , PA (PA6, PA66) , PC, PE, POM, PP, etc. 

coating part: TPE, TPR, TPU, TPV, TPEE, PVC, etc. 


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