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Steel rule die for Pe

Yan_b

Aluminum
Joined
Sep 19, 2007
Location
Israel
Hi guys, I need to make a die/device to pierce 40mm diameter round hole through woven laminated PE sheet/tarp, this stuff looks like the material plastic bales sacks are made of, but with extra laminated layer that prevent it from unwove.
the thickness is 0.18mm and preferably I would like to punch two layers at once as the product is a sleeve.
Need to make about 20,000 holes or so, for low production rate with a man standing next to the machine.

Basically I thought of making a rule die/or turning punch in that basic design, and use pneumatic cylinder to drive the punch over a backing plate.

Now I have zero experience with rule dies, I did some quick testing with some punch I made on no real design basis
and tested on shop press, now while it cut the sheet the force require seems to destroy the backing plate quite fast, I tried with plywood , some unknown rubber but I guess 90 shore area, Teflon sheet and some pe soft sheet.

So my questions, is it a feasible process for such operation?, if so what geometry/ or recommended rule to use (if it can be installed in such small diameter, and what backing material to try?
 

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A stell rule die should work. As you mentioned your cutting die is important, one way is to allow the cutting pad to move a bit at each cut so to present a new surface , for a disposable cutting surface you can use mdf which is hard, flat and cheap.
 
I'm thinking a rotating thin wall tube with the edge bevel on the inside, in a drill press. It will cut a clean hole and not disturb the surrounding fabric until the edge forms a burr. You could stack 10 or 20 sheets if space/geometry allows. Tube collects the cutouts and would have to be cleared regularly. Having a ring cut into the backer does not affect the cut.
 
Thanks' guys, I experimented with the process some more and turned out that Delrin back plate gives good results, the drill process is interesting but do to the nature of the material I foresee wrap disaster potential.
 
The die shown has far too tall and steep a cutting geometry, you should be fine with the edge no more than 1mm tall and a 45 degree angle to the inside (straight outside). Most important, you want a tough steel (like an S7), properly hardened to around 55-60RHC. Spend the money to get it done by a competent Heat Treat company, unless you have the right equipment and experience.

http://cintool.com/documents/Shock_Resistant/S7.pdf

Delrin or polycarbonate sheet is what I prefer as a backer.
 








 
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