How do manufacturers prevent sink marks in thick sections of PVC sculptures?

Sink marks are a common issue in PVC sculptures, especially in thick sections where uneven cooling can cause surface depressions. Manufacturers employ several techniques to prevent this problem. First, they optimize the injection molding process by adjusting parameters like injection speed, pressure, and cooling time. Slower cooling rates and uniform temperature distribution help reduce internal stresses.

Another method involves modifying the design of the sculpture itself, such as adding ribs or coring to thick sections to promote even material flow and cooling. Using high-quality PVC with additives like fillers or stabilizers can also minimize shrinkage. Additionally, advanced cooling systems, such as conformal cooling channels in molds, ensure consistent heat dissipation.

By combining these strategies, manufacturers achieve smoother, defect-free surfaces in PVC sculptures, even in thicker areas. Proper mold design, material selection, and process control are key to preventing sink marks and ensuring high-quality results.