Need Help!- circles arent circles

[xlr8r]

when i layout circles on autocad2002 they wont cut as circles they cut sortof a rounded square.what am i doing wrong?this has cost me a bit so any help is appreciated.thanks

[NC Cams]

We had a similar problme on our CNC mill.

Following two issues can be at play - hardware and software.

Cutting a circle with CNC is hard as your'e aksing the machine to simultaneously do things the oppossite way and do wo with the velocity goinf rom min to max and max to min at the same time on both axis. Thus, you cutter software may not be ding thigns fast enought to handle the code processing.

Next issue is that of slop in machine. YOu essentially get 4 direation changes. ANY and I do mean ANY (that's ok, it aint rocket science" slop will show up in circle cutting. Sorest should be at 12, 3 6 and 8 o'clock. Thse are whre msot back lash slop occures. Depeningg on softare issues noted and harware slop, you can get footballs and sort of rouned squarea.

The hardest thing for a CNC to do is make/cut a ROUND shape. We spent a fortune on our Bridgeprt Extrak to get it do do so we were shooting for 0.0001 reoundness and got very very lcose. WE cut masters for cams and they have to be that good. You're results may not that level of analness. Ours did.

IF softwere is not the problem, machine slop surely is/may be. It was in ours.

[Edwardo]

I know with using corel3x sometimes i have to increase the nodes for circles and arc's otherwise they end up looking like what you say, and save the drawing as curves.

EDD

[xlr8r]

i save from auto cad to coreldraw ill try it thanx!the machine cuts circles perfect so im sure its not a slop issue but i am goin 2 doubl it