What are the reasons for crack defects in injection molding?
When we process injection molding, we often produce some unnecessary defects due to some small reasons, which will cause some troubles to our injection molding. Among these defects, the most common one is crack defect. So, what are the reasons for crack defects in injection molding?
1. A large proportion of recycled materials is added to the raw materials, which makes the raw materials shrink in a large direction or the filler is unevenly distributed;
2. The raw material plastic is contaminated, volatile or poorly dried;
3. Improper demoulding design, small demoulding slope, thin product wall with sharp corners and notches, resulting in stress concentration;
4. Short holding and injection time, too long or too short cooling time;
5. Low or uneven mold temperature, slow injection speed, low pressure;
6. Improper molding conditions, high stress and poor ejection;
7. Improper use of release agent, uneven cooling after demoulding, etc.