
Plastic Injection Molded Hole Design Guide
Hole Design Core pins are raised features in the mold that form internal features such as holes, openings, and grooves. They can also be used

Hole Design Core pins are raised features in the mold that form internal features such as holes, openings, and grooves. They can also be used

Design boss outer diameters at 2.5–3.0 times the inner diameter to prevent sink marks, while maintaining a wall thickness ratio of 0.6 relative to the

Sawtooth threads are optimal for thermoplastics, featuring a 0.035–0.070P root radius to minimize stress. For bidirectional loads, use Whitworth forms with a 0.137P root radius

Optimize snap-fit reliability by selecting L- or U-shaped geometries to extend beam length, ensuring assembly strain remains below the material’s permissible limit. This approach effectively

Maintain rib thickness at 50–60% of the nominal wall to prevent sink marks and ensure structural integrity. Incorporate a 0.5–1.5° draft angle per side to

Calculate press-fit interference by limiting hoop stress to 20%–25% of the material’s short-term tensile yield strength. Apply thick-wall cylinder theory to balance assembly force and