When plastic injection molding, the inner stress easily occurs and get crack. The plastic parts have stress cracking as the action force or solvent action.
How to avoid the stress cracking? There are many ways.
1) You can add additive in the plastic raw material to enhance crack resistance. Fully dry the material before the injection. Set reasonable molding conditions.
2) When designing the plastic parts, fully consider the parts shape should be reasonable and don’t set inserts which can reduce the stress concentration.
3) When designing the mold, should increase the draft, choose reasonable gate and exit system.
4) Strictly control the material temperature, mold temperature and injection stress etc.
5) After the plastic injection molding, the parts should have after treatment to enhance its crack resistance, relieving internal stress and forbid to contact solvent.