Different plastic materials have different characteristics.There are the handling considerations in the injection molding process.
1. Processing of plastic
PC is a plastic raw material with a high water absorption rate. It must be preheated and dried before processing. The proportion of recycled materials can reach 20%. In some cases, 100% recycled material can be used, and the actual portion depends on the quality requirements of the product. Recycled materials cannot be mixed with different color masterbatch at the same time, or it will damage the properties of the finished product seriously.
2. Selection of injection molding machine
The requirements for the plasticizing system of the injection molding machine are well mixed, corrosion resistance and conventional plasticized.
3. Mold and gate design
Common mold temperature is 80-100 ℃, plus glass fiber is 100-130 ℃, pin gate can be used for small products, gate depth should be 70% of the thickest part, other gates have ring and rectangle. The larger the gate, the better it is,which can reduce defects caused by excessive shearing of the plastic. The depth of the vent hole should be less than 0.03-0.06mm, the flow channel should be as short and round as possible.
4. Melt temperature
The air injection method can be used to determine the processing temperature.
5. Injection speed
Fast injection speed is used widely, such as electrical switch parts.
6. Back pressure
The back pressure is about 10bar,which can be reduced appropriately without air lines and color mixing.
7. Residence time
If the residence time is too long under high temperature, the material will be degraded, and CO2 will be released, and it will turn yellow.
Do not use LDPE, POM, ABS or PA to clean the barrel. PS should be used for cleaning.
Post time: Jun-19-2020