How to select injection molding screw

Plastic injection machine screw and barrel has the function of conveying,melting,mixing,compression,measurement and exhaust,which playing an important role in plasticizing quality. Screw and barrel is the main core unit of the plastic injection molding machine,such as the heart of the human, which can directly reflect the performance of the machine.So how to choose a good screw and barrel is the problem of the plastic injection machine manufacturers.

The screw has several critical parameters to influence the quality of plasticization,and according to the following principles to select a good screw for your Plastic injection machine.
1.Screw diameter
Screw diameter related to the amount of injection required.In general, the diameter of screw is inversely proportional to the pressure of the highest injection,which is proportional to the plasticizing ability.
2.Delivery section
Responsible for the conveying of plastic,pushing and preheating,and preheating the tube to the melting point.Crystalline plastic should be long,such as POM and PA.Non-crystalline material secondary,like PU,ABS,and the shortest heat sensitivity,e.g.PVC.
3.Compression section
In charge of the mixing,compression and pressurization of plastics,through which the raw materials of this section have been almost completely melted.In this area,the plastics gradually melts, and the volume of the spiral must be reduced to reduce the volume of the corresponding plastic,or the material is not solid,the heat transfer is slow and the exhaust is bad.
4.Metering section
Generally account for the length of the work of the 20%-25% screw, ensuring that all the plastic melts and the temperature and mixing average.