The causes of cracks in plastic mold: due to the residual stress caused by the forming conditions (full model); residual stress release occurs; the shape of the product caused by stress concentration; the same insert thermal expansion error caused by the deterioration of materials.
Metal insert block in advance, then can ease the formation of residual stress, the same principle, with the shape of the annealing in place of block heating is also a way. The measure is the most effective one in the molding setting condition, with the decrease of the injection pressure. If the release pin is balanced, the release point is added to the force of the larger point.
Measures to deal with:
1 .raise the barrel temperature, reduce the injection pressure, and reduce the ejection speed.
2. improve the mold cavity of the finish.
3. should be enough to balance the distribution of ejector pins, design products do not have acute angle, and to avoid the thickness difference of products.
Because of polycarbonate (PC) PVC and other materials are easy to stick in the chrome layer mold, especially in the corner of a cone, so to give attention. Polycarbonate (PC) easy to crack in the mold insert, like the best in materials include glass fiber reinforced as well. There are products of residual stress due to solvent, oil, medicine pay, will crack (here stress cracking), trace oil pay will produce a lot of crack effect.
Note: the above information by the Dongguan Plastic mold factory finishing in the Internet, welcome to reprint, indicate the source!