Intro
14%
Common build failures: what actually goes wrong on the shop floor
The recurring build screwups that scrap forge dies in the first 50K cycles, grouped by where in the build chain they originate, and the inspection step that catches each one before it ships.
A buyer takes delivery of a new H13 hot-forge die. The heat-treat certificate reads 50 HRC, the nitride certificate reads 0.30 mm case, the polishing report reads Ra 0.4 µm on the cavity. The die cracks across the parting line at hit #80. The post-mortem is depressing. The build was on spec at every step. The build was also wrong.
Lesson 11 mapped the four failure modes that scrap forge dies in service. This lesson covers the build screwups that produce those failure modes early. The mechanisms are the same. The cause is upstream. A die that cracks on hit #80 from thermal fatigue did not fail because of thermal fatigue. It failed because something in the build chain put a crack initiation site, a soft spot, or a retained-austenite reservoir in the part before the first hit landed.
The six recurring screwups group into four themes by where they originate in the build chain: heat-treat mistakes, EDM mistakes, design and machining mistakes, and supplier mistakes.