small cnc router

[Claude Boudreau]

I have build a small cnc router with 425oz/in stepper motors, with the ACME rods used 10turns/inch (delrin nuts)I get a speed of maybe 35 inches/minute. I have seen speed advertise of over 100 in/min are they using stepper with belt drive and are servo faster and stronger?

[LeeWay]

I run those same motors on my router and get 300 IPM rapids. I use 62 VDC 6 amp power supply and Gecko 203's.
I just use home brew roller skate bearings for the guides, but now use 5/8" double nut Thompson screws for X and Y and just single nut on Z.

The acme rod will steal some of your speed. The type of drives and the power supply may also limit your speed and torque. Your guide rails come into play then too.

You have to look at the whole machine. The motors are very capable with the right accouterments.


Mine are all direct drive as well.

[Claude Boudreau]

what is the tread per inch on your acme or ball screw or are you belt driven?Dont you have any problem with missing step at these speeds?Iam using xylotec driver , pretty sure cannot go that fast...

[ger21]

Those motors running on a Xylotex can suffer from mid band resonance with those motors. For best results from those motors and a Xylotex, buy or make some dampers to minimize resonance, and change screws to something with 2-5 turns per inch. But if you really want a lot of speed, you'll need to switch to Gecko's or something that can run at much higher voltages.

Lee's ballscrews are probably 5 turns per inch, btw.

[LeeWay]

Gerry is right. My ballscrews are 5 per inch. I initially had a Xylotex and a little smaller motors on this machine running on 28 VDC power supply. I could get at best 72 IPM on Y and 60 on X. The Gecko's and bigger supply and larger motors basically more than trippled speeds and it has more holding torque as well as accelerating quicker. My gantry weighs over 100 pounds I think.