To help you get started with injection molding part design, we've created a comprehensive checklist that covers the key considerations and best practices outlined in this article. Download the checklist now and ensure that your part design is optimized for injection molding:
This comprehensive guide breaks down the essential rules of injection molding part design into simple, actionable concepts. 1. The Golden Rule: Maintain Uniform Wall Thickness
A is a taper added to the vertical walls of a part, allowing it to be removed from the mold easily. Without draft, the part will stick, leading to scratches, drag lines, or stuck parts. General Rule: Add at least 0.5∘0.5 raised to the composed with power 1∘1 raised to the composed with power
Apply a minimum draft angle of 1.5 to 2 degrees to all vertical faces parallel to the direction of the mold opening.
For most general-purpose applications, the ideal wall thickness is between 1.5 mm and 3.0 mm . injection molding part design for dummiespdf exclusive
Depending on the material, ideal wall thicknesses generally range from 1.5 mm to 4 mm. Going too thick wastes material and increases cycle time, while going too thin can prevent the mold from filling completely. 2. Add Draft Angles to Every Wall
: The mold opens, and pins push the completed part out. Polymer Behavior
The wall thickness around the hole of the boss should be 50% to 60% of the main wall thickness.
: Non-uniform shrinkage across different areas of the part. To help you get started with injection molding
If you ignore every other piece of advice, remember this: .
Are all structural ribs designed to be less than 60% of the main wall thickness?
Beginners often try to make a part stronger by making it thicker. As we discussed, thick walls lead to sink marks. The professional solution is to use ribs.
Convert thick solid areas into hollow structures with a constant wall thickness. The Golden Rule: Maintain Uniform Wall Thickness A
Generally, walls should be between 1mm and 4mm (0.040" to 0.160") depending on the material.
Bosses are cylindrical standoffs used to accommodate screws, threaded inserts, or locating pins during product assembly. Because they are localized thick sections, they require careful design to prevent aesthetic flaws. Design Guidelines
Bosses should be designed to prevent sink marks. The thickness of the boss base should be roughly of the main wall.