: As a rule of thumb, ribs and bosses (the posts used for screws) should be about 40% to 60% of the thickness of the main wall to prevent "sink marks" (dimples on the surface). 2. Let it Go: Draft Angles A Beginner's Guide to Injection Molding - Protolabs
: If you must change thickness, use a ramp to transition between the two areas. injection molding part design for dummiespdf exclusive
The single most important principle in injection molding design is maintaining uniform wall thickness. When plastic cools, it shrinks; if one area of your part is significantly thicker than another, it will cool at a different rate, leading to internal stress. : As a rule of thumb, ribs and
: Instead of one solid chunk of plastic, "core out" the area to create a hollowed-out shape supported by ribs. The single most important principle in injection molding
Designing for injection molding can feel like a high-stakes puzzle, but once you master a few fundamental rules, you can create parts that are both functional and cost-effective. Whether you are a hobbyist or an engineer in training, this guide breaks down the "holy trinity" of injection molding: , Draft , and Material Selection . 1. The Golden Rule: Uniform Wall Thickness