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Causes and solutions of top whiteness in injection molding products

Release time:2021-08-16

When the plastic parts of injection products are ejected from the mold, if the ejector pin is used, the ejector rod will often leave deep or shallow marks on the plastic parts. If these traces are too deep, the so-called top white phenomenon will appear. In serious cases, the so-called top explosion will occur when the plastic parts are pushed through.

The main reason for the whiteness of plastic parts is that the product has a large mold adhesion force, and the ejection part on the plastic parts causes white marks at the ejection part of the ejector rod. The specific reasons and improvement methods are as follows:

1. Back mold temperature is too low or too high: adjust the appropriate mold temperature.

2. Too fast ejection speed: slow down the ejection speed.

3. With demoulding chamfer: overhaul the mold (polishing).

4. The ejection of finished products is unbalanced (the ejection leaf spring is broken): repair the mold (make the ejection balanced).

5. Insufficient number of thimbles or improper position: increase the number of thimbles or change the position of thimbles.

6. Vacuum occurs in the mold during demoulding: clean the dirt in the ejector pin hole to improve the air inlet effect.

7. The finished bone and column positions are rough (inverted): polish each bone and column position.

8. High injection pressure or holding pressure: reduce the pressure appropriately.

9. The demoulding angle of the finished mold is too small: increase the demoulding angle of the rear mold.

10. Improper action time or position of side slider: repair the mold (make the core pulling action normal).

11. Ejection area is too small or ejection speed is too fast: increase the ejection area or slow down the ejection speed.

12. The injection speed of the last section is too fast (Burr): slow down the injection speed of the next section.

These are the reasons and solutions for the whitening of injection molded products.

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