Parting Line Selection in Injection Mold Design
The parting line in an injection mold is the separable contact surface between the mold halves that allows for the removal of the molded plastic part and the solidified runner system. The selection of the parting line is a crucial step in injection mold design, as it directly impacts product quality, production efficiency, and cost.
Principles for Selecting the Parting Line:
Ensure product appearance quality and precision. Avoid placing the parting line on visible product surfaces to minimize parting line marks. For complex-shaped products, consider concealing the parting line on the sides or back without compromising aesthetics.
Maintain mold component rigidity during molding. Choose parting lines along thick wall sections and avoid placing ejector pins or inserts in thin walls.
Facilitate side-action core pulling. For products with side-action ejector pins, avoid placing the parting line perpendicular to the ejector pin direction to minimize ejector resistance.
Enable easy part ejection. Avoid placing the parting line in product recesses to prevent ejection difficulties. For complex-shaped recesses, consider incorporating draft angles or ejection mechanisms on the parting line.
Optimize manufacturability. Choose parting lines with simple shapes, avoiding complex curves or surfaces. Consider machining methods and process limitations for machined areas.
