Punching and blanking disks

[sunthorn]

I am in the need of some information.

In a current process I am punching out stainless steel disks (2.25 diamx3mill) from 500'x 2.5" rolls. I can get a better price on 500'x2.375" rolls. I have no problems on getting the tooling to accept the new roll size. I am afraid that side clearance of 1/16" from the punching process now will lead to deformations/waving around the disk as it is punched out. Any suggestions or insights about my fears bearing fruit?

 

[ornerynorsk]

If your material is only 3 mil ( 0.003) and you need only the disks and not the scrap bridge, you should have no problem what-so-ever.

 

[smcadman]

The last post threw me off By 3 mill do you mean .003" or 3 millimeters (11 ga.)?
If you mean .003", then I do not forsee any problems.
But If it is 11 ga, then 1/16" remaining at each quadrant may be cutting it too close. Depending on what kind of die clearance and stripper you are using, deformation may be a problem. Cut a 2.375 x 24" strip from scrap metal and punch it to find out for sure.

Flores

 

[DerrickWayne]

I've had to do this kind of blanking before and concern for web width was great. What we did was use a compound blanking die and supported the material using nitrogen loaded cylinders. I don't recall the PSI used but am certain it was in the 1200 PSI range. This eliminates the concern relating to edge distortion as it supports the blank and carrier web during the cutting process.
On another note, I'm a bit concerned about the amount of waste you are currently getting by blanding in a row, with a narrow strip width. If your volumes warrents it, you might want to reconsider this and go with a multi cavity compound die and maybe blank 3 or more disks across. Again ... press size (tonnage and bed size)and volumes will dictate what you should do.
I hope this helps you.

 

[ornerynorsk]

Clearance on .003 material will be so tight as to be negligible. You should have no problem with 1/16 scrap bridge, especially if your clamping the material just prior to the punch hitting with a stripper of some sort.

 

[235]

Experiment is required. The coil is suppose to have a camber 1/8" in 10'Lg, but not allways is in this tolerances.
Stripper with nitrogen cylinders is required and closer tolerance than usual 8% of material thickness as well. And when the punch gets dull, it will try to extrude more material from 1/16" edge.
If it is not too expensive, you can purchase 1 coil 500'x 2 3/8Width (11Ga) and run it. It makes difference if you blank a single piece or run it from a coil.
dako@kolev.com