Injection Mold - Design Guide

Before we look at specific features, we must adopt the mindset of the mold maker. An injection mold is a pressurized vessel. Typical melt pressures range from 10,000 to 30,000 PSI. Every design decision must answer one question: How does this affect melt flow and ejection?

Sharp inside corners create stress risers.

: Position ejector pins at structural areas like ribs, bosses, or sidewalls so they do not punch through thin nominal walls. injection mold design guide

Use 3.0 to 5.0 degrees of draft where metal slides against metal to prevent tool wear. 3. Ribs, Bosses, and Corners

Draft is the taper applied to the sides of a part to facilitate its removal from the mold. Before we look at specific features, we must

The mold opens, but the part sticks to the core (B-side). How do you get it off?

Used for internal undercuts, lifters sit on an angle within the ejector mechanism. As the ejector plate advances, the lifter moves both upward and inward, releasing the internal lip or snap feature. Every design decision must answer one question: How

Mold cycle times scale with the square of the wall thickness. Keep walls as thin as structurally possible. Transition Gradually