Movement in straight lines while carving

Need some help.

Im carving stars for the union on a flag, and I’ve noticed that a lot of the stars get a little curvature to the straight sides. I’m cutting .25” using a 90 degree bit at .06 per path. Any help would be appreciated.

Machine not rigid/firm enough.
Tried doing the same in MDF which do not have fiber direction?


Thanks ! When you mean machine do you mean belt tension / v heels? Or are the table on which I have the machine is not stable enough?

With “Machine” I mean the entire system as it all have impact.

  • If the V-wheels/belts are too tight a lot of the initial force from the stepper need to counter friction, then suddenly moves. (think “ratchety / jagged” motion)
  • If the system is too soft, each time the bit flute engage the bit bounce away a smidge in the opposite direction. This can also cause the jagged edge. (google “cnc chatter”)
  • If you have a poor bit or poor cut parameters the cutter/opposing forces may be greater than what your machine is capable of handling.

I am seeing surface imperfections and bleeding of the blue color.