Performance: unmelted particles near the material head. It is impossible to obtain a smooth surface for thin-walled products.
Physical Reasons: because of the short production cycle of thin-walled products, It has to plasticizing on a high screw speed, so that it can make the melt in the screw barrel to shorten the time remaining.
In the production of thin-walled products, usually include PE, PP, PC, etc., technicians will try to reduce the melt temperature to shorten the cooling time, not completely melted particles will be injected into the mold.
Firstly, reasons and improvement measurement related with machining parameter:
1, melt temperature is too low, increase the barrel temperature.
2, screw speed is too high, reduce the screw speed.
3, screw back pressure is too low, increase the screw back pressure.
4, the cycle time is short, that is, melt residue in the barrel of a short time, to extend the cycle time.
Secondly, reasons and improvement measurements related to the design:
Irregular screw geometry, the use of appropriate geometry of the screw (including the measurement of shear zone).