Defect
Strength poverty
Cause
1. Lack of drying
2. High resin temperature
3. Too much cushion volume
4. Shear heat generation at the runner and the gate
5. Residence time too long
Countermeasure
1. Preliminary dry the pellet well enough
2. Drop the cylinder temperature
3. Reduce the cushion volume
4. Make the runner and the gate bigger, and shorten the gate land.
5a. Use the molding machine with appropriate injection volume(about 1.5 to 3 times more than the cavity volume)
5b. If resin remains inside the cylinder by some kind of trouble, resume molding after purging it.
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