（38） Ejectormarks Injection Molding Process Defect Handling Manual (65 types)

It is apparent that the phenomenon of stress whitening and stress increase is found on the side of the product facing the nozzle, that is, where the ejector rod is located on the ejection side of the mold
Physical causes
If the necessary release force is too high or the surface of the ejector rod is relatively small, the surface pressure here will be very high, resulting in deformation and eventually whitening of the ejector part.
The causes and improvement measures related to processing parameters are shown in the following table:
1. Pressure maintaining too high to reduce pressure maintaining
2. The pressure holding time is too long to shorten the pressure holding time
3. Switching the pressure maintaining time too late will advance the pressure maintaining switching
4. The cooling time is too short to extend the cooling time
The reasons and improvement measures related to the design are shown in the table below:
1. The release angle is not enough. Select the release angle according to the specifications
2. Rough surface in the release direction Polishing the mold in the release direction
3. A vacuum core is formed on the ejecting side and an air valve is installed inside the core