Cutting 1 Inch Acrylic

In this instructable I'm going to be explaining how to cut out 1 inch thick acrylic pieces on the shopbot.  It sounds simple but there are some things that can be done to aid in the finishing process and make your life a lot easier.

Tools needed:

- ShopBot
- 1/2 in single flute bit
- A design
- CAD to CAM software (in this case, VCarve Pro 6.0)
- Chisel
- Mallet 

I took my design and laid it out in illustrator, and input a .dxf into VCarve.

So I cut these with an initial PROFILE, and the a FINISH cut.

Once your file is set up and ready for a cut file to be created now you have to set your bit and feeds and speeds for each cutting path.

Now set up your profiling bit feed and speed.

- 1/2 inch bit
- 14000 rpm
- 2.25 inches/second feed rate

These are what I found yielded a nice chip out and wasn't too rough on the machine or the tooling.

Now setup the cutting path.

What I do to keep the parts stable in the whole sheet and also maximize vacuum until the pieces are totally cut out is I cut the profile but leave a 1/32 on the bottom so it doesn't quite go all the way through.

And for this initial profiling path I also offset the cut 1/32 of an inch larger so the final pass goes in and shaves the final 1/32 off the side and the bottom on a full depth pass.

Now set up the finish cut profile.

- 1/2 inch bit
- 18000 rpm
- 1 inch/second feed rate

This profiling will yield a much smoother edge finish because the bit is faster and it is feeding slower so it contacts the material more times.  Depending on your tooling you might have to adjust this because it will want to melt the plastic and gunk up your bit and the edge, so be careful.

On this finish pass I am cutting full depth plus 15 thousands of an inch.

The full depth pass will result in a uniform edge without depth passes making it easier to finish treat the edges.

For this full dept pass don't forget tabs. Remember this is shaving off the 1/32 inch on the side and the bottom, so I just make the tabs 1/32 of an inch and 1/4 inch wide which is more than enough to hold the pieces in.

Remember when saving our cut file out, to make sure you run the profile first and then the finish pass or else you will most likely damage your parts and your bit or even the machine.

So now holding your part in should be a 1/32 inch thick tab.  This is very easily chiseled out or even cut with an box cutter.

I just take a deadblow and a chisel and put the flat part of the chisel against my piece and lightly tap the chisel and it breaks off the tabs smoothly.

So this is how you get thick acrylic pieces cut out with a easily finished edge.  Finishing the edge to clear will be in my next instructable.

Thanks.