k factor and bend radius

[dogarila]

I started recently with this company that does a lot of stainless steel sheet metal bending. Regardless of the thickness they always use a k factor of 0.18 and a bend radius of 0.001, which is wrong. The actual bending rad in the final product is larger than 0.001. They say that these values give the best representation of the flat pattern in SW drawings. My question is: Has anyone did some testings and came up with real world values for k and bend rads?

 

[MadMango]

It all depends on the tooling being used, the method for forming the bends and material.

We use a K-factor of .434 and default bend radius of .063 for all materials from 20ga-10ga. We arrived at these numbers through several rounds of tests and close coordination with our fabrication department.

If your company says it works for them, why argue the point (even if they are probably wrong)? Does the final part pass inspection to the drawing? That is what matters.

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[CorBlimeyLimey]

You should find out what forming tool radius the shop actually uses & apply a K-factor to suit.

The .001" rad may work OK for the flat, but will not create a model which is a true representation of the actual part.

An actual part which meets "form, fit & function" is of course paramount, but IMO, with a little bit of thought & effort they could have all the elements (model, flat & part) accurate & true to life.


Helpful SW websites faq559-520
How to get answers to your SW questions faq559-1091

 

[Standing]

We have an outside shop build all our sheet metal parts. They say forget K-factor they will set it. And for bend radius they always use 1/32 radius unless we really need something different.

Bradley

 

[APPENG]

Perhaps instead of k factor, you might want o sondier developing a bend table.. Sounds like you have hard shop data to build one that suits your needs and then you will have a true to like model, and a flat pattern that compensates for the materials behavior under the shops bending conditions.

hope that helps

Regards,
Jon