[sm38240]

Local area craftsmen are working together to machine face shields out of 30 thou thick PETG. This will be the clear plastic visor. Need any insight on getting this thin stock with my CNC. Vee bit? 1/8" end mill? Feed rate suggestions. Also, hold down options. Since I normally work with wood, I use clamps on my MDF spoilboard, but clamping for this thin stock is not an option .

Ideas appreciated!

Stan

[thomasjrusso]

how about a drag knife?

[sm38240]

Not a bad idea. I ended up mounting rare earth magnets in my spoilboard and holding down the plastic sheet with fender washers. Used an 1/8" downcut bit. Worked reasonably well. Probably the best solution is a vacuum. Ended up cranking out 200 face shields for the local healthcare providers.

[lambodesigns]

I've been doing the same thing with a vacuum table. Cutting at 150 ipm using a 1/8" straight cut bit. I'm sure a down cut bit would work much better but a straight cut was what I had on hand. You would think that this would really suck down to a vacuum table but I had a lot of trouble with the material coming up and as soon as it starts to curl you lose all vacuum and then bad things happen. Ended up only cutting 5 at a time and also taping down all the edges. I've probably done 500 of them so far.