Analysis of causes for dissatisfaction of injection products

The main causes of injection dissatisfaction are lack of material and improper injection pressure and speed (including excessive pressure loss caused by resistance). It may be caused by the following reasons:

1. Reasons for injection molding machine:

If the plasticizing amount or heating rate of the machine is uncertain, the machine with large plasticizing amount and heating power shall be selected;

The wear of screw and barrel or rubber head causes the material return and the actual filling modulus is not in line; The actual temperature of the barrel is too low due to the failure of heating system such as thermocouple or heating ring; The sealing element of the injection cylinder is worn, resulting in oil leakage or backflow, which can not reach the required injection pressure; Too small inner hole of nozzle or improper adjustment of nozzle centrality causes too much resistance and pressure consumption.

2. Reasons for injection mold:

1. If it is difficult to feed due to the low temperature of part or the whole die, the die temperature shall be increased appropriately;

2. The distribution of mold cavity is unbalanced. The wall thickness of the part is too thin, resulting in excessive pressure consumption and poor mold filling. The wall thickness of the whole part or part shall be increased, or an auxiliary flow or gate can be set near the insufficient filling.

3. Pressure loss caused by too small flow channel of die; If it is too large, the glue injection will be weak; Too rough will cause dissatisfaction. The size of flow channel shall be set appropriately, and appropriate arc transition shall be applied at the transition between main flow channel and shunt channel, gate or its own turning.

4. Poor exhaust of mold. The material entering the cavity is blocked by the gas pressure that is too late to be discharged, resulting in insufficient filling. It can make full use of the gap of the screw to exhaust or reduce the clamping force, use the parting surface to exhaust, and set up exhaust channels or pores when necessary.