What Are the Molding Methods of Plastic Injection Molding?

1. Exhaust type for plastic injection moulding

The exhaust injection machine for exhaust plastic injection moulding applications has an exhaust port in the middle of the barrel and is also connected to the vacuum system. When the plastic is plasticized, the vacuum pump can extract the water vapor, monomer, volatile substances and air contained in the plastic through the exhaust port. The raw materials do not have to be pre-dried, thereby improving production efficiency and improving product quality.

It is especially suitable for the moulding of easily hygroscopic materials such as polycarbonate, nylon, plexiglass, and cellulose.

2. Flow type of plastic injection moulding

Flow plastic injection moulding can use ordinary mobile screw injection machine. That is, the plastic is continuously plasticized and extruded into the mould cavity with a certain temperature. After the plastic fills the cavity, the screw stops rotating, and the material in the mould is kept under pressure for an appropriate time by the thrust of the screw, and then cooled and shaped.

Flow injection moulding overcomes the equipment limitations of producing large-scale products, and the quality of the parts can exceed the maximum injection volume of the injection machine. Its characteristic is that the plasticized objects are not stored in the barrel, but are continuously extruded into the mould, so it is a combination of extrusion and injection.

3. Co-injection of plastic injection moulding

Co-injection moulding is a method of using an injection machine with two or more injection units to inject plastics of different varieties or colors into the mould simultaneously or sequentially.

Composite products of multiple colors and/or multiple plastics can be produced by this method, and the representative co-injection moulding is two-color injection and multi-color injection.

4. Runnerless plastic injection moulding

The mould is not provided with a shunt channel, but the molten material is directly injected into each cavity by the extended nozzle of the injection machine. During the injection process, the plastic in the runner remains molten and flowing, and does not come out with the product when demoulded, so there is no runner residue in the part. This precision plastic injection moulding method not only saves raw materials and reduces costs, but also reduces the process and can achieve fully automatic production.

5. Reaction injection of plastic injection moulding

The principle of reaction injection moulding is to pump the reaction raw materials into the mixing head after being metered by the metering device, collide and mix in the mixing head, and then inject into a closed mould at high speed, quickly solidify, demould, and take out the product.

It is suitable for processing some thermosetting plastics and elastomers such as polyurethane, epoxy resin, unsaturated polyester resin, silicone resin, alkyd resin.

Our injection molding company in China has a mould and moulding design and development team. Therefore, we are able to provide a full range of services. We are always listening to our customers' needs and will continue to expand our capabilities to meet every challenge. We have accumulated a great deal of experience and understanding of the real possibilities in this field. If you have any needs, welcome to consult us.

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