Picture of 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 
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Step 1: Machine and File Prep

Picture of Machine and File Prep
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.

Step 2: Initial Profile Bit

Picture of Initial Profile Bit
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.

Step 3: Initial Profile Path Setup

Picture of Initial Profile Path Setup
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.

Step 4: Finish Profile Bit

Picture of Finish Profile Bit
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.
cglaw20131 year ago
kikiclint2 years ago
you can always use a regular circular saw if you turn the blade to run backwards. I've done it for Polycarbonate when I worked glass in the past.
Really? flip the blade backwards... and it works?
c0lin2 years ago
I'm curious about the use of these acrylic slabs. What do you use them for?
guyflagg (author)  c0lin2 years ago
It was a project for a client.
guyflagg (author) 2 years ago
Very true. The edge is never as nice or consistent, and this is pretty much "set it and forget it". But you cant cut rounded rectangles on a table saw.