Injection Mold Design Guide Updated Jun 2026

The mold can only be as good as the part design. Verify these first:

For more detailed technical specifications, you can review the Xometry Injection Molding Guide or Protolabs Design Tips . Injection Molding Design Guide - 3 Space

Maintain a distance of 2 to 2.5 times the channel diameter between the channel center and the cavity wall.

Use a tapered sprue with a 2 to 3-degree included angle to allow easy extraction.

Injection Mold Design Guide Principles Best Practices and Tips injection mold design guide

: Keep the height of raised text between 0.3 mm and 0.5 mm . Text exceeding 0.5 mm may require a draft angle to prevent the letters from sticking or breaking off during ejection.

Uneven cooling causes internal stress, leading to warped parts.

Draft is the taper applied to vertical walls to allow the part to release from the mold.

These lines form where two separate plastic flows meet. Place gates so weld lines occur in low-stress, hidden areas. The mold can only be as good as the part design

Always, always run a DFM (Design for Manufacturing) review with your mold maker before machining steel. The $500 cost of a DFM analysis can save $50,000 in tooling modifications later.

. This is structured to be highly scannable for engineers, product designers, and students. Comprehensive Guide to Injection Mold Design 1. Introduction to Injection Molding

Place ejector pins at structural areas like ribs, bosses, and vertical walls to avoid flexing or puncturing the part.

Sharp corners concentrate mechanical stress and restrict plastic flow. Replace sharp internal corners with a radius equal to 50% of the wall thickness. Design external radii to equal 150% of the wall thickness to keep wall dimensions perfectly uniform. 4. Gating and Venting Systems Use a tapered sprue with a 2 to

For continuous internal threads or deep bulbous features, segmented cores collapse inward mechanically to clear the obstruction before ejection. 7. Mold Material Selection

He sent the new design to the mold shop.

keep the runner channels heated to eliminate material waste. These systems require no runner removal, reduce cycle times, and improve part quality, though they involve higher initial costs. Recent innovations include valve gate hot runner systems that enable precise control of melt injection.