# Y Axis Sticks on start up



## DEJ090233 (May 31, 2019)

Hi,

Wondering if anyone has experienced this before? My DIY CNC right side Y axis sticks in place when I fist power it up. The left side will move, but the right side does not. After it has been on and I have manually moved it some it loosens up and works correctly. This is very strange behavior. 

Has anyone every experienced this? If so, what was the solution?

Thanks!

FYI, the machine is 1500mmx1500mm with dual Y axis motors.


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## TimPa (Jan 4, 2011)

I guess that I would check all of the cabling and connections in the motor circuit, making sure connections are bright and tight. is there more friction on that side of the gantry travel than the other (rails, screws, etc.)? is there a lubrication maintenance that needs done? are there belts or gears involved in the drive, that may need attention?


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## DEJ090233 (May 31, 2019)

Thanks for the reply! This is a brand new machine. It's all 1610 ballscrews and 15mm linear rails. All of the connections are good and the axis runs very smooth when not connected to the gantry. I have basically dissembled and reassembled the entire machine trying to fix this. Since it's new ( received all of the parts in late Feb), I haven't thought about lubrication yet, but I will check that.

The part I don't get is that once I move it around some it works fine.


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## TimPa (Jan 4, 2011)

if all the same, you could swap the left and right motors to eliminate them. what brands is it? check with manufacturer?


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## difalkner (Jan 3, 2012)

Welcome to the forum! Add your first name to clear the N/a in the side panel and so we'll know what to call you.

Post some photos of your machine and setup on the axes. What controller software are you using? How about the hardware - what are you using there? The more detail you give us the better advice you'll get.

David


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## MEBCWD (Jan 14, 2012)

Hi David, Welcome to the Router Forums.

Have you checked to make sure the gantry is 90 degrees to the Y axis? Does this happen when the gantry is all the way forward or all the way back?


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## difalkner (Jan 3, 2012)

Thanks for adding your first name, David!

With everything off does it stick if you try to push it back from the stops? Or is it easy to push with no binding? If it sticks or is difficult to push I would drop the steppers out of the loop and see if it is easy to push or binds in any manner (remove belts or whatever it takes to take them out of the picture).

David


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## 4DThinker (Feb 16, 2014)

What kind of CNC do you have? We bought a Probotix CNC that had the same problem and the cure was a new parallel cable to connect between the PC and the controller box. 

4D


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## DEJ090233 (May 31, 2019)

Thanks for the reply's everyone. This is a DIY Machine 1500mmx1500mm using C Beam extrusions, .5" aluminum plates, ball screws and linear rail on all axes. I have 2 48V power supply's running drivers and motors with the Spark Concepts CNC x-PRO V4. I'm not using the on board drivers on the board, but external drivers. I have found out that my motors are pretty high inductance (9.0), so I plan on replacing these, but since it's only one side of the Y axis having problems, I wouldn't think it's a problem with power? 

The gantry is square to the machine, have checked it numerous times. 

The screws do seem to run very smoothly when not engaged. I have taken the gantry off and I can run the screws up and down very easily. I have also unbolted the gantry from the screws and can push to gantry from one end to the other with one finger.

I think I will try switching the motors and see if the left side has a problem? I think this will tell me if it's mechanical or electronic.


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## honesttjohn (Feb 17, 2015)

Latest problem I had with my Probotix X axis not following the program files turned out to be the stepper driver in the control box.


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## ger21 (Feb 10, 2019)

Because the issue only happens when you first turn it on, and then it gets better, I'd suspect something with the electronics. 
Are the two motors using separate power supplies?


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## difalkner (Jan 3, 2012)

DEJ090233 said:


> This is a DIY Machine.


We'd still like to see photos of what you've built.

David


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