Curved material - drill holes before or after bending?

[orlorob]

Part of an assembly I'm working on is a curved/arc sheet.

Per my design prints, there are three holes positioned at different angles of the arc.

I'm sure that I could put the holes in after the sheets have been formed, but I have several to do, and it would be much more labor intensive than drilling the holes while the sheets are still flat.

SOOOOOO... question - am I setting myself up for disaster if i drill all the wholes before I bend the sheets? Are there measurement factors to be accounted for that I should know about?

Thanks,
Rob

 

[mcintya]

It would depend on how accurate the position, size, and shape of the holes have to be.

 

[ornerynorsk]

The tighter the radius, the more distortion in the holes if you pre-drill. Remember, metal also stretches when you bend it, making for some interesting location issues. If you only have a few pieces, I'd say bend first.

 

[KenZalucki]

You could always bend and then laser cut. Laser cutting is accurate within .001". Depends on if you want to do it yourself or outsource. Bit more expensive, but nevertheless and option.

 

[sacem1]

If you pre drill a smaller hole before bending you will have the location and starting center for your final hole which will be done after bending, that way you will enjoy part of the benefits and problems of each alternative.

Cheers

SACEM1

 

[BIMOTA]

Stamping die processing methods always complete forming operations before any piercing operations are initiated.

 

[orlorob]

Thanks to those who commented.

Since the holes were already drilled on hundreds on these parts, I had no choice but to move ahead and hope for the best.

It turned out alright. There was negligable deformation of the holes after bending, so the parts meet the customer requirements.

-rob