On Thursday, 30 November 2017 19:03:40 UTC, Bazza wrote:
A few of the products I receive have a manufacturing defect which may cause problems in time.

The issue is tears in the metal at a point where the metal blank shape is pressed to create to upright "wings" which form the hinge part of the assembly. The assembly is a rat trap. The metal is galvanised mild steel.

This link shows a photo ... www.tomdhu.com

Any suggestions how this could be avoided? Different radius ? Lubrication? Two stage forming? Heat?

Baz

It's been cold formed.
Shudda been done hot.
Or the design changed.

The failure is caused when the crystaline structure of the metal changed as it's deformed.