Curtis, have you considered a laser instead of a CNC? You mentioned the final part size is 5" x5" so even a small laser would work. I have a Hurricane 60 watt 16" x 20" laser and I have cut up to 3/8" acrylic with it. It will cut 1/2" but I haven't tried it yet. Makes perfect straight lines that are ready for gluing right out of the laser. I currently buy full size acrylic sheets and then rough cut them with my saber saw to fit in the laser. $5k is a little low for a brand new machine like the one I have, but you may find a used smaller machine in that size or you can import a machine directly from China and maybe get something that would work for the $5k range. I have a CNC and the Laser and I can tell you the laser is way easier to use than the CNC and is a lot faster. And you don't have to worry about clamping the material down or vacuum pumps. You just set it on the work surface and press start. The laser never touches it so it doesn't move.
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Mark Smith
Tracy, CA
Mark's Custom Woodcrafts
Legacy Artie 58 CNC
Hurricane Ivan 60 Watt Laser