[christofer]

Hi, Im doing a CNC conversion to my new X2. Im mounting my 425 in/oz stepper to the left side of the X axis using a custom mounting plate and a helical coupler. I can't seem to get above about 20 IPM before i start to loose steps. I have aligned the screw as parallel to the table movement as possible, but above 20 IMP it still seems to "stall" at times. Im using a 36v PSU and the 3a, 40v Keling drivers with Mach3. Is 20 IPM what i should be seeing here? Should i be happy with this? Also, should i be able to stop the handle turning by hand when the axis is moving?

Thanks for any help!

[hoss2006]

Hey christofer,
I have nearly the same setup except I'm using 282 oz/in on the X.
I get 125 IPM rapids and that's with the gib screws pretty tight.
Try moving the leadscrew by hand with power off so you can feel where it's binding
to get it lined up.
You didn't mention if you're using ballscrews so the pitch of the leadscrew itself could cost you rapid speed.
I would only be getting 31 IPM with the original 20 tpi leadscrew so your 20 IPM
wouldn't be far off.
Try setting the microstepping to 1/4 or 1/2 or even full step mode.
I can stop my 495 oz/in by hand when it's running by grabbing the handle so that part is normal.
Hoss

[christofer]

Thanks Hoss, i was able to get to 30IPM today. I am using the stock screws on my machine. They are 16TPI. I think the majority of my alignment issues were caused by me assuming the screw is centered under the table, when it is actually about 1/8" to the back. The first thing i will be making on my cnc machine is a proper mounting plate.

[benji2505]

Be extremely cautious with non aligned steppers and ballscrews. I doubt you will be able to fix the issue with a new fixture for the stepper. We broke off our ballscrew with a non aligned setup. We solved the problem with a flexible coupling that you can get at McMaster-Carr. We have used the coupling on page 1147 of their catalogue and it works great. The values for the torgue that it can take shoudl help you with your choice.