Causes Of Warpage Of Injection Molded Products

- Jul 25, 2018-

2. Plastics

The crystal type has more chance of warping deformation than the amorphous plastic, and the crystal type plastic can be used to correct the warpage deformation by using a crystallization process in which the crystallinity decreases as the cooling rate increases and the shrinkage rate becomes smaller.

3. Processing

(1) The injection pressure is too high, the holding time is too long, and the melt temperature is too low. The speed is too fast, which causes the internal stress to increase and warpage.

(2) The mold temperature is too high, and the cooling time is too short, so that the parts at the time of demolding are overheated and the ejection deformation occurs.

(3) Reducing the screw speed and the back pressure reduction density while maintaining the minimum charge amount to limit the generation of internal stress.

(4) If necessary, the mold can be soft-shaped or demoulded after the mold is easily warped and deformed.