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How can sink marks in plastic products be eliminated?

Sink marks are surface defects that commonly appear on plastic products. They are typically small depressions or indentations that can mar the appearance and quality of the final product. These marks occur due to uneven cooling, insufficient packing pressure, or improper gating and venting during the molding process.

To eliminate sink marks, several measures can be taken. Firstly, optimizing the cooling system of the mold to ensure uniform cooling across the entire part can be helpful. Secondly, increasing the packing pressure and holding time can force more plastic material into the cavity, reducing the likelihood of sink marks. Additionally, adjusting the gating and venting locations and sizes can improve the flow and pressure distribution of the molten plastic, minimizing the formation of sink marks. Careful material selection and proper mold design also play crucial roles in preventing this issue.