UMO+ Shaking

[AminMissaoui 0]

Hi gyus,

I have an issue with My UMO+ that i just assembled, when it reaches the x/y limits  it starts shaking badly,
In consequence some of the bolts are getting loosen up.

Any ideas on how to fix this problem?

 

Thanks

[JohnInOttawa 104]

Welcome!

 

First couple of questions:  Is this happening when you try to home the printer, or does it happen just during a print?

If homing is working fine, but prints are hitting this issue, then it may be a setting thing.

 

Assuming it happens at homing, then read on....

 

I have a UMO, not a UMO+, and the problem you describe sounds similar to something you can get into with CNC construction, so let me offer the following:

 

My first guess (and it is only that) would be that the cross slides are going past the limit switches so you are getting a collision with a hard item, like printer structure or a rod.  If this is the case, then the shaking you are observing may be belt teeth jumping on the pulleys or the stepper motors stalling.

 

So it might be good to troubleshoot the limit switches, mechanics, signal, setting.

 

Now, my comparator is  UMO, not a UMO+. so I am assuming the limit switches are the same mechanical ones for both.  If that is true, I would start troubleshooting with the power off, confirm you can move the print head manually with little force, then move it manually to its limits.  If your room is quiet enough, you should hear the limit switches clicking when they are made.  If you don't hear the click when you would expect it, slide the print head where you would expect it to stop and have a look to see if the limit switch slider are positioned as they should be.  You'll need to check this on both ends of the X and Y axis. 

 

If the mechanics are correct, then I would check that you have the positive limits wired to positive inputs and aren't reversed, as during zeroing the printer will hit a stop then back up slightly, but only if the switch is where you told the printer it would be.

 

If wiring is correct, then settings, I believe there are reversed axes on the UMO+ as there are on UMO, but disclaimer again.  Your setup guide will help.

 

Not sure if any of the above is of use, hopefully it will at least get you started. Others who know more will likely get you closer to a solution quickly once they join.

 

Cheers

John

 

 

Edited April 30, 2018 by JohnInOttawa

[AminMissaoui 0]

@JohnInOttawa Thank you for your reply,

Yes the problem is happening at Homing, i did check the limit wires and it looks fine, also the position of the limit switchs them selves theres is like 3 mm ditance between the limit switch and the sliding blocks,but yet it's still chaking becasue somehow when it reaches the limits it doesnt move smothely, i think it has someing to do with X Y axels.

[JohnInOttawa 104]

I'm confused by your description of the 3mm gap.  Did you test the travel with power off?  Can you physically slide the blocks until you hear each limit switch click?  Do you feel a change in resistance to movement before you get that click?

 

Maybe if you can post a picture or two of the position of the slider blocks after an attempt to home that would help.

 

John

[AminMissaoui 0]

Actually you were right about the wires and that was the issue, x and y were reversed!
Promblem solved
Thank you verry much for your help!

[JohnInOttawa 104]

Great to hear!  Enjoy!

 

Cheers

John