In injection molding short shot defect cause by molten plastic does not fill the cavity, product marking is incomplete.
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I. Cause of short shot.
+ Molten plastics are stick or cold in runner system.
+ Mold structure is not good so molten plastics can not fill in the cavity.
+ In injection molding process, air can not go out of the mold by air vent so it will create pressure to make short molded defect.
+ Resin temperature or mold temperature is low so molten plastic is cold in the mold.
+ Injection pressure or speed is low so molten plastic can not fill the mold.
+ Nozzle or return valve of injection machine is error so injection pressure is low.
II. injection molding short shot troubleshooting.
1. Product design.
Recheck thickness of product, if need we can increase thickness of product.
2. Mold
+ Change the position of gate to where thickness of product is biggest.
+ Increase cross-section of gate or increase gate number.
+ Increase dimension of runner.
+ Create air vent at short shot location.
+ Check the air vent dimension, increase depth of gas vent.
+ Increase mold temperature.
3. Improve short shot by molding equipment.
+ Increase injection pressure, injection speed
+ Increase the cylinder temperature, and nozzle temperature, too.
+ Change new injection machine with higher injection pressure or speed.
+ Increase the amount os material feed.
+ Increase holding pressure.
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