Originally Posted by jsheerin  I have the G540, a 48V PS, the Keling 425oz motors, and 1/2-10 5 start acme screws with dumpster cnc nuts on my 4'x4' cutting area router. I have dual x motors and screws driving a gantry that's ~100lbs. I get rapids around 270ipm. For the Y axis, I get somewhere over 400ipm (I forget exactly), and even higher on my z, but I have that set at 400 as well. I have the acceleration turned down on the x, but the y and z are pretty snappy. I'm still getting started on cutting - I was cutting test shapes today to square up the gantry - so I can't tell you how fast I can reliably cut at. For resolution / accuracy, I'm typically seeing errors of around 0.001"-0.003" in my cuts and can move a a few thousandths if required. I think a lot of the error I see is due to the lead errors of the screws though. It typically returns to the same position within less than 0.0005". Anyway, this should be plenty accurate for wood. Hope that helps.
After I bought my electronics and learned some more, I was looking at one of the lower torque Keling motors - maybe a 387oz-in?. If you look at the torque curves of the 425 vs that one, the 425 had higher holding torque obviously and higher torque up to a certain rpm, but above that the smaller motor had more torque. I had figured out where the crossover point was in speed for my setup, and I seem to remember it being higher or right around the fastest that I planned on cutting at, but that would be something you might want to look at. |
Thanks, that is what I was looking for. I'm likely going to end up with a set up similar to yours and now have an idea how fast it will be. In fact it is faster then I thought it would be. I suppose the other dumb question to ask is to get your dual X motors working did you use a breakout board to send the "X" signal to two of the G540 drives and just invert the output of the slave drive motor? And one more question, would it make sense to put a 2 start on the Z axis since speed there isn't as important and I might be cutting guitar inlays etc? Would more accuracy in the Z axis make sense here?