Undercuts

An undercut is any indentation or protrusion that prohibits an ejection of a part from a one-piece mold.

Typical undercuts

Below are 3 typical undercuts that are frequently seen in molded parts:

holes

windows

clips

Disadvantage of the undercuts

Adding cost to tooling and molding, as they make the molds and production complicated. For considering of cost-saving, you are recommended toto eliminate or minimize undercuts as possible.

Solutions of the undercuts

Here are three solutions to re-design of your parts to eliminate or minimize undercuts.

For holes

For windows

For clips

Notes: considering part functionality or geometry, undercuts are neccessary for some parts.

Undercuts not moldable

Some undercuts may not be moldable, which could be overlooked by designers.

If you are not sure about the undercuts for manufacturing, talk to Plastopia. We will analyze them and provide guideline to change the part design. Below are a couple of examples we help for our customers.