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

On 30/11/2017 19:03, 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


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.

--
for full context, visit https://www.homeownershub.com/uk-diy...m-1253766-.htm

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.

On 01/12/2017 08:26, harry wrote:
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.

Or simply the strain has been too much and the material yields.

The tooling needs to impart less stretching of the steel.

On 01/12/17 14:41, Fredxx wrote:
On 01/12/2017 08:26, harry wrote:
On Thursday, 30 November 2017 19:03:40 UTC, BazzaÂ* 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 ...Â* 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.

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.


--
Truth welcomes investigation because truth knows investigation will lead
to converts. It is deception that uses all the other techniques.

On Friday, 1 December 2017 15:21:14 UTC, The Natural Philosopher wrote:
On 01/12/17 14:41, Fredxx wrote:
On 01/12/2017 08:26, harry wrote:
On Thursday, 30 November 2017 19:03:40 UTC, BazzaÂ* 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 ...Â* 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.

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.