Hi Chris, Chris Reynolds wrote: > I'm new to the group and I could use some help with a problem that I'm > having. I just built a new cnc machine and I keep running into a problem that > I can't figure out. I've been doing some test cuts, > problem is they always come up short on one end. I thought it was a > backlash problem so I put the dial indicator on the machine and ran it to an > inch. It came up like .040" short. So I > tried adding a backlash command to the ini file and that didn't fix it, > so it wasn't a backlash problem. Then I tried messing with the steps > and finally got it to come out right. Run it to an inch, dead on 0, run it > back to 0 and end up dead on 0 again. So then I run the > program again and the whole thing is now to long. It always seems to > come up short on one end. Checking the math the steps are right, I have a 20 > tooth pulley on the motor and a 40 tooth pulley on the leadscrew, running in > full step mode, so that comes out to 1600 steps per inch, which is what I > have in the program. It's almost like it's a compounded problem, like it's > off a small amount but then when you cut through the whole part it adds up. > But the weird thing is that it's off on one end. The part I'm cutting > resembels a comb, where you have slots cut into the part every so often, > there's a wider section at each end, on the far end it's right, on the 0,0 > end of the part that wider section is to short.
I think that you are loosing steps. It may be that the MAX_VELOCITY or MAX_ACCELERATION settings for the axis [AXIS_0] ... [AXIS_2] in your .ini file are too large. You could test with very low values to check if that is the problem. Luc ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
