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Author Topic: I could really use some help with motor tuning...I think  (Read 6162 times)

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Re: I could really use some help with motor tuning...I think
« Reply #20 on: May 28, 2013, 01:01:46 AM »
Well I wish I had noticed that setup menu before, would have saved me a lot of time :) Now I have got the X & Y tunes really nicely but I found my real problem; the Z axis binds as it moves up and down. My computer is about 10' away from the spindle so I didn't notice it til I was manually jogging the spindle up after it buried itself in the project yet again. As I was watching I could see it stuttering as it moved up and when I ran it back down it stuttered again.

So Now I get to pull the whole danged Z assembly apart and try and figure it out.

What is the best way to measure the two round bars it moves up and down on to see what needs to be adjusted?
Re: I could really use some help with motor tuning...I think
« Reply #21 on: May 28, 2013, 01:06:49 AM »
Here are a couple pictures with the spindle removed. Even with the spindle out it still binds as it moves up and down.

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Re: I could really use some help with motor tuning...I think
« Reply #22 on: May 28, 2013, 03:38:07 AM »
I suppose the easiest method which is likely owned by most people is a digital caliper. If you hold one jaw on the ball screw and have the other on the outside of one rail, you can then measure at varing positions to get it running in line. You would likely be best to have a shim of some sort between the jaw and the ballscrew so that you are sure you are not measuring slightly in one of the ball tracks. If you then get one rail set that way and then the other then that should get things aligned pretty close.
 Of course that method will only work if you are sure the ball screw is actually in line in the first place, so it may mean you have to readjust the whole lot a second time.
 What I think I would do is set it up as described and then place a Clock (DTI) on the base with its needle against the Z  then raise the slide and see if the needle stays constant, if not then it shows you need to adjust the whole lot again to offset things.

Hood
Re: I could really use some help with motor tuning...I think
« Reply #23 on: May 28, 2013, 05:24:19 PM »
Thanks Hood. Before I get too much further into pulling things apart, could being too slow on that axis cause it to hang up? THat's what the sales guy in China that didn't understand anything about Mach3 when I needed specs is saying now that I'm saying there is an issue with their setup.

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Re: I could really use some help with motor tuning...I think
« Reply #24 on: May 28, 2013, 05:28:29 PM »
Unlikely, especially as you have steppers. Steppers produce the greatest torque at standstill and it drops off with speed so the slower you go the more torque you have. If going slow is stalling the stepper then going faster will just make it worse.
Hood
Re: I could really use some help with motor tuning...I think
« Reply #25 on: May 28, 2013, 05:29:26 PM »
That's what I thought, thank you :)