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 ...
Any suggestions how this could be avoided? Different radius ? Lubrication? Two stage forming? Heat?
Baz
A larger radius should fix it.
If it doesn't then you will have to do it in steps but that costs more.
replying to Bazza, Iggy wrote: They're not actually tears, they're cuts, since the forming is perpendicular to the edge. The extra material will actually shoulder any future collapse. The only way to avoid it, if desired, is to cut/stamp the piece out with a square cornered cutter. Even a so-called "zero radius" cutter would require a similar cut. The left cut-ear looks to be bent to the left, that's likely the side which sat against the anvil (forming machine's static block) and the other side was pushed or hammered to form both.
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.
Or simply the strain has been too much and the material yields.
The tooling needs to impart less stretching of the steel.
Or the steel quality needs to be more ductile at the time of forming.
This is yypical of a mould made for one steel qulaity being shipped over to woggawoggalamd and used on recycled ship steel etc etc.
Could be made of recycled steel. Full of crap like aluminium, copper, tin and lead.
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