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I need to cut a piece of plexiglass and need some advice on rpm's and move speed

  • Onsrud has an excellent web site with recommendations for all kinds of plastics. You'll find the site at www.plasticrouting.com. You'll probably want to start at about 18,000 RPM with a feed speed of about 1-1/2 ips to 2-1/2 ips.
  • The smaller the cutter diameter the faster you want to spin (RPM) but not anything above 18 000 RPM in Acrylics. For 1/8" CED I set the RPMs at 14,000 with a 1 O-flute tool and 12-13,000 RPM with a 1/4" cutter diameter, depending on the shapes. Using an Alpha tool, if you have a very good hold down and mostly straight cuts (say rectangles), you can move at up to 4-5"/sec. with a 1/4" diameter cutter and up to 3"/sec. with a 1/8" diameter cutter. If you're doing odd shapes like letters you might want to slow down (up to 50% of the above).
  • Spiral O-flute bits work better in plastics that straight O-flute bits because they kick back and shake less
  • When cutting acrylic the main goal is quality of cut and not speed. Step down .06-.10 per pass because the edge quality is SO much better than trying to optimize chiploads and cut expensive (1") material in 2 or 3 passes. Finish with a light allowance (0.01") to remove any stepdown marks.
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