UC The Finance and Administrative Services Abbreviation

Undercut

A notch or groove melted into the base metal next to the toe or root of a weld and left unfilled by weld metal. A portion of stream channel underneath an overhanging bank, log, rock etc. The void behind the rib, on rebar, usually caused by backlash. Can be a design flaw that results in an indentation or protrusion that inhibits the ejection of the part from the mold.  Other times undercuts are designed into a mold to ensure a part holds onto the correct side of the mold.