small circles or arc slow down feed rate .

[Battwell]

after using/ testing some of the more advanced chinese controllers they have reference speeds for smaller circles where the feedrate is reduced according to radius.

a few of my customers are lazy and leave tool feedrates high and expect things to work perfectly.

obviuosly with heavy gantry machines with high inertia small circles can deform with high feedrate.
this would be a fantastic feature to add to the motion planner.
with high acceleration and high rapid speeds set in uccnc the trapezoidal planner doesnt catch these.

eg. if a 6mm tool is set for general cutting at 10m/minute and the same tool is used to try to create a 15mm circle
the resulting circle will be out of shape.


giving this small circle a reference speed of 500mm/minute makes it cut perfectly.
every doubling of the reference circle cuts at the double of the set feedrate so a 30mm circle would cut at 1m/minute.
enlarging circles increments up until the max tool programmed feedrate is reached.

[ger21]

I've always wanted to add this feature to my AutoCAD CAM macro I use, but was always too lazy to get to it.
Even our new Morbidelli can't cut round holes.

[cncdrive]

Yes, this is a good idea.

[Battwell]

Would this be hard to implement into the motion planner ?
Possible?

[ger21]

Would this be hard to implement into the motion planner ?
Possible?

Do you do this for all arcs? How do you differentiate circles, as there are a lot of ways to program a circle in g-code.

[Battwell]

i dont know how they implement it in the controller.
im presuming by arc radius.

the motion planner is extremely good.
its a 6 axis controller with full rctp.

but this is also in their simpler 3/4 axis controls too.

[cncdrive]

OK, but why don't you just set your CAM software to program arcs feedrates like that?

[Battwell]

my customers are using a big mix of cam programs to create code.
vectric, fusion, mozaic etc.
they are also lazy and do not adjust the feedrates from the tools setting in the tool selector.
eg the tool default may be set to 20m/minute for straight line work.
thats why i like this feature in the dd and weihong controllers.
i do explain everything on their training day but - ......they do what they want
this is the speed they are taught to use for production work.
https://youtube.com/shorts/FdeJdcT5PpM? ... irVmJt09Vx