I am trying to cut perfect circles about 100mm in diameter. The file gets about half way complete and decides to plunge straight into the acrylic. I believe it is a tool heating/ wrong tool type issue but wasnt sure since I am new to this. I am using a sold carbide 1/4 in fish tail double flute. Each pass only takes off about 1mm of acrylic. After 3 or 4 passes i can hear the router struggle and it plunges into the acrylic. I am using PORTER-CABLE 690LR router. Any suggestions?
Have you tried looking at the gcode simulation? OpenSCAM (http://openscam.com/, yeah, terrible name) lets you plug in your gcode and check if it does something reasonable. Also, that router is a beast, far larger than most spindles -- is the spindle trammed? If the bit is not square, it's possible that it begins catching on the edge as it goes deeper. Heavier spindles may cause some sagging, which lead to out of square bits. Try this tutorial: http://www.shapeoko.com/wiki/index.php/Calibration_and_Squaring_the_Machine#Tramming I have no problem taking 1.5 mm passes @ 400mm/min, and I have a much smaller router (Makita RT0701)
