Ordliste
Undercut — definition
Geometry that prevents the part from releasing straight out of the die, and therefore requires a moving core.
An undercut is anything that grips the tool: a hole in the side, a groove, a hook, a thread across the draw direction.
The remedy is a slide core. Technically that is no problem, but it costs: a more expensive tool, a longer cycle, an extra parting line on the part, and one more mechanism that can wear or jam.
Often the undercut can be removed with a small geometry change that does not affect the function. It is one of the first things we look for when reviewing a drawing.