1. Possible reasons:

　Insufficient cavity compound, causing shrinkage:

     1 insufficient filling or insufficient feeding

     2 improper gate location or gate asymmetry　

     3 runners, gates are not enough or too small 　

     4 product wall thickness or thickness is uneven, the back of the thick wall is prone to dents

　Solution: Make adjustment correction 

     1 increase the feeding or open the large opening gate 

     2Restrict the melt glue from flowing into the sprue gate and not flowing into other gates. 

     3 increase the runner and increase the gate size 

     4 can modify the mold mold or increase the injection pressure

2, possible reasons: 

　Improper adjustment of process technical parameters:

     1 shot pressure is small, the glue is slow　 

     2 shot time is too short　 

     3 holding time is too short 

     4 cooling time setting is too short

　Solution: Make adjustment correction

      1 adjustment to increase the injection pressure and injection speed 

      2 increase the shot time setting value

      3 increase the dwell time set value 

      4 increase the cooling time set value

3. Possible reasons: 

　  Plastic overheating:

     1 plastic overheated, the fuser temperature setting is too high 　

     2 mold temperature is too high 

     3 The mold has local overheating or overheating when the product is demoulded

　  Solution: Make adjustment correction

     1 reduce the temperature setting of the melt cylinder 

     2 Reduce the mold temperature and adjust the cooling system inlet valve 

     3 Check the mold cooling system or extend the cooling time 

4. Possible reasons: The material temperature is too low or the plasticization is poor, which makes the melt flow poor.

 　 Solution:  Increase the temperature of the heating zone of each section of the melter and check the degree of plasticizing.