Round Corners

Hello together

im facing since lately this issue:


instead of going into the edge, the machine makes a round corner.

i have read about putting G64 PX in the beginning and it works.

BUT! it insanely slows down!

is there another way to get a better result?

thx for your help

The reason the machine is slowing down is because at a corner one axis must decelerate to a stop and the other must accelerate from stopped to the feed rate, but at the point there will be an instant of full stopped.

The G64 Pn setting sets a tolerance to how close the movement must come to the programmed path. G64 with no P tolerance is infinite blending and the corners will be rounded to their maximum for the machines acceleration settings.

It is simple physics and geometry you can't make a square corner without stopping. If you round the corner you can go faster, and the faster you can accelerate the less rounded the corner must be to maintain a certain speed around it.

You have to work out a compromise to determine what G64Pn setting will give you the fastest possible speed, yet still maintain an acceptable tolerance for your work. The larger Pn is the faster and more rounded the machine can go around the corners, if Pn is smaller the rounding will be less, but it will take more time.

G64Pn where n=the minimum resolution of the machine (such as 0.0001inches), might be a good setting for extremely precise work. 50-100 times that is usually a pretty good compromise that usually won't make noticeable deviations on a machine like a wood router.

Em vez de seguir pela borda, a máquina faz uma curva arredondada.

Li sobre usar o comando G64 PX no início e funciona.

MAS! Fica absurdamente lento!

Existe outra maneira de obter um resultado melhor?

Unfortunately no. Linuxcnc must follow the acceleration settings you used in your machine configuration. If your acceleration settings are too slow for your machine you can increase them. But if they are already set as fast as your machine can go, the only other option is to rewrite your g-code to be smoother so the machine does not need to stop and start so much.

Another consideration would be if your G-code has a lot of transitions from short G0 moves short to cutting moves.  This can cause serious slowdowns because those transitions are treated as full stop positioning moves with no blending.  They are the equivalent of programming in G61 mode instead of G64Pn. (Actually I think all G0 moves are full stop positioning moves.) Sometimes changing all G0 moves to G1 moves can significantly improve runtimes.