Laser-cut fixture for milling polycarbonate by MarkU

Last crawled date: 2 years, 11 months ago

I use a lot of polycarbonate, but unfortunately it's not laser-friendly, so I wind up milling it. I lasercut this fixture out of acrylic to hold 4" wide strips of 3 mm polycarbonate, a convenient stock size that works well in my Taig CNC mill.
It allows repeatable positioning (I can loosen the M6 bolts, slide more polycarbonate in, and tighten them again and run the same job without having to re-zero), keeps the material fairly stiff while cutting, and doesn't waste a lot of room with big clamps around the edge. NB make sure you have enough cutter length so the collet clears the M6 bolts at maximum depth. I run a 1/16" 2-flute spiral cutter at 600 mm / minute at top speed and it climb cuts nicely. Moving in the conventional direction I get strings of polycarbonate which wrap around the cutter and melt onto it, and scar up the work piece (circular scar in fixture at upper left side is an example of this).