cutting 25mm clear acrylic

Good day

I am trying to cut letters off 25mm clear acrylic using a CNC machi

My bit is 6mm O- flute, new
I tried 18k spindle speed, 5000 feed rate , 5 steps of 5mm deep each
The bit gets hot , the plastic melts onto it

I am wonder if some one can advise me

Thank you in advance
Nissim Cohen

Hello,

For me, making two cuts per depth have helped. With stepover of 0,2mm

Hautamak