which setting should be put because the plexi will not melt
It’s not about how fast to go, lowest spindle speeds (depending on your machine) with a higher feed rate with a zero-flute end mill cutter
FYI: Try using Cass acrylic instead of plexi
I’ve tried them all the same problem
I work with Cass acrylics all the time and never have a melt down.
what feed rate are you using per inch?
I would run a fast feed rate, more like 4000mm/min and a thin pass depth about 0.5mm . And make sure its cast acrylic and not extruded acrylic.
I also noticed that your bits all say 2 flutes, however this setting has no effect on the toolpaths.