Just a quick word on this, for your consideration. What plastics don’t like is the heat that may accumulate locally from the cutting action, but this does not necessarily mean that one should minimize the RPM. This was one of my initial thoughts but a long time ago @gmack set me straight, I tested myself and became a believer (that what matters in plastics is to feed fast, even faster if spinning fast too, but that one could get a perfect cut in plastics at 24.000RPM too…). Numerous tests later I still increase the feedrate (a lot) whenever I see signs of melting, and this always works. Bottom line, plastics require high chiploads, whatever the RPM/feedrate combination is selected. It’s also a good opportunity to see the machine operating at 200ipm, which does not happen every day when cutting wood or metal 
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