Re: [CAD_CAM_EDM_DRO] Holding thin sheet

Joe,

I've been working off two rolls I bought from a tool supplier in the SF
Bay Area 3-4 years ago. They were recommended as a source by a friend
using the tape and I ordered the rolls without a purchase order. I don't
recall the name of the company, nor do I have the records to look them
up (outside of trying to sift through a couple years worth of canceled
checks). MSC sells double backed tape, and most hardware stores sell a
double backed carpet tape. I've used carpet tape before, I seem to
recall it holds pretty darn good.

I thought about this a bit more and had some additional thoughts.
If you know where the desired patterns will be, you can use smaller
spots of tape instead of trying to cover the whole part with tape. That
will help with removal. Try to keep them as close to the edge as you
can. Cutting through a lot of the tape can cause the flutes to gum up
with tape and collect chips.
You might be able to use finger pressure as the cutter finishes off the
part to insure it doesn't shift. Also, if you have some straight
sections, try leaving some bridges about .005 or so thick. With CAM, it
would be pretty easy to do this on a curve as well. You'd raise the tool
about .005 above the bottom of the material, continue milling (maybe 2x
cutter dia), then plunge back down to full depth and carry on.
these bridges would insure the part doesn't shift and can be easily
removed. When I cut out the three windows on that delrin part, I made
the last pass about .003 above bottom. The slugs popped out easily after
I'd removed the sheet from the fixture.

Good luck!

Jon