1、 Causes of product cracks:
1. Residual stress due to forming set-up conditions (overfull mold)
2. Residual stress during demoulding
3. Stress concentration caused by product shape
4. Error caused by thermal expansion of the same insert
5. Deterioration of materials
2、 Associated knowledge:
1. Same cause of deformation in the last section
2. If the metal insert is heated in advance, the residual stress during forming can be relieved. In the same way, forming can be used
Post annealing is also a way to replace the heating of the insert.
3. In the setting conditions of molding, the most effective method is to reduce the injection pressure.
4. If the release pins are balanced separately, a larger force is added to the release.
1. Instant: raise the temperature of the barrel, reduce the injection pressure and reduce the demoulding speed.
2. Short term: improve mold cavity finish.
3. Long term: the angle of demoulding should be enough, the distribution of demoulding pins should be balanced, and sharp angles should not be designed on the products
Try to avoid the thickness difference of products.
4、 Due to material differences:
1. Because polycarbonate (PC) PVC and other materials are easy to stick on the chromium plating layer of the mold, especially on the corner
Become an inverted cone, so pay attention.
2. Polycarbonate (PC) is easy to crack at the die insert. In this case, it is better to use the material
It's better to add reinforced glass fiber inside