x axis still shuddering

Brent Dowell

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Is it affecting the quality of the engraving? Was kind of hard to tell.

At 54 seconds in I do hear some clicking? Interesting.

If you loosen the belt, does it move freely?

are you able to increase the voltage on the motor driver a bit maybe?
 

Darren Wright

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Is X the one your z axis rides on? I noticed a what looks like one of the wheels didn't seem to be spinning every once in a while like the outer ones were, specifically the back right hand one in the inside. Just wondering if one of them is hanging up on you.
 

Dan Noren

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that one on the inside doesn't ride on the rails, it is a guide idler that the belt uses before going up and over the geared pulley, there is one on the other side as well. that clicking you hear is the sound that is made when it is shuddering. it starts to make the sound at 44 seconds, then 50, 54, and 57 seconds. that constant noise in the background is the fan on the pc, it rubs a little when it is running. loosening the belt didn't help. one of the things, that when caught in the middle of a shudder, and i kill the job, it will not move left or right, but sit there and shudder. only after i kill power to the hardware, and move the x axis, will it move freely again. i checked the power to the motor, and couldn't get a reading that made sense (-.4 to 1.3-1.6), so, i lowered it all the way down (getting a straight line), then upping the power until it moved and looked good. still got the shudders.
 

Brent Dowell

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one of the things, that when caught in the middle of a shudder, and i kill the job, it will not move left or right, but sit there and shudder. only after i kill power to the hardware, and move the x axis, will it move freely again.
Was this the new stepper you put on it? I had a problem on my old printer where I had that same problem. Turned out the back bearing on it was shot and there was some 'stuff' that came from the bearings that would get caught up in the stepper and cause it to skip steps and eventually 'freeze'.

Once I turned off the machine, and could get it unstuck, it would appear to work fine for a while. I'm suspecting a bad stepper. Do you have another stepper you could replace it with and see if that works better?
 

Dan Noren

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started out with the old motor, and still happens with the new motor. the new motor is part of the set when i replaced the y axis motors. no problems with either of those.
 

Brent Dowell

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Can you take some pictures of:
1) The control board
2) The X axis motor controller on the control board
3) The wiring connectors for the x motor
a) on the control board​
b) on the motor​
c) Any intermediate connections/splices in between (if any)​

In general, when I've seen this problem the issue I've had were:
1) Stepper motor overheating.
When it is running, how hot is the X stepper
2) Stepper motor bearing has stuff in it from a failed bearing
Swap one of the 'good' y motors with the x motor to see if it is the stepper or something else.
3) Not enough voltage going to the stepper
You've adjusted this before, maybe turn it up a bit?
4) Belts too tight
5) axis not moving smoothly, i.e. something causing the axis to freeze up.
Disconnect the belt and verify there is nothing mechanical causing it to freeze up.
6) Make sure that the wires are all good and that the connections are solid.
I've had issues on machines where the cheap insulation on the wires cracked causing exposed wires.
7) Speed and acceleration settings.
Verify that you don't have to high of acceleration settings. It's possible that the X axis is trying
It could be that the machine is trying to change x directions too fast.

Well, Those are off the top of my head.

First thing I would do is to swap a y stepper with the X stepper to rule out problems with the motor itself. Even a brand new motor can arrive with issues.
 

Darren Wright

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In addition to Brent's requests for more info Have you felt the motor when it's doing this and does it feel warm/hot to the touch. I had one years ago that was overheating, but it was quite noticeably warm. Looks like with that tall Z axis it could just be too much weight for that motor too.
 

Brent Dowell

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Looking at it again, are the idler pulleys on the X turning freely?
G0 X0
G0 X200 (or whatever the width of the x axis is)

Just keep running that X back and forth and see if it starts to skip steps doing that. Make sure everything is spinning freely.
 

Darren Wright

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Dan I looked at that video during the times you mentioned. That idler/wheel is not moving when the carriage wheel to the right of it is moving. Looking like it's binding or has a bad bearing. It rotates some in the video, but not during the studder like the one to the right is.
idlerwheel.PNG
 

Dan Noren

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ok, here come the answers. all wheels spinning freely now. stepper motor is ice cold. the motor that is there, is one of the new ones, same as the y axis. very odd that the old and new motors having the same problem. getting enough voltage. belts are just taught, not over tight. x axis moves freely from stop to stop, by hand with the power off, with ugs, and lightburn with the power on. all connections are tight, and the wire is a good grade, 18 ga., 4 wire shielded cable. speed and acceleration are at 50mm/min. the z axis isn't that tall, only 200 mm. i will have to upload the pics after i get home. did a quick test, the title messed up. ran it again, title ok, but half way down it is screwing up again. got the pics to work, various points of the wiring hook ups, and the test.

IMG_20200615_105917056.jpgIMG_20200615_110046245.jpgIMG_20200615_105958476.jpgIMG_20200615_105954799_MP.jpgIMG_20200615_113720519.jpg
 

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Dan Noren

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to make sure it wasn't just what i was trying to engrave causing the problem, i tried it out on a line drawing, and it did pretty much the same thing. i noticed today, that i still have the old 2 nema 17's, one of which i can test with. instead of going through the fun of disassembly, i will just wire it in, and test with the laser off. if it stutters, then we have something else to look at, as 3 motors all can't have the same stutter. if it runs fine, i may consider swapping out the new motor.
 

Brent Dowell

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Yeah, swapping out a motor to rule that out would be a great idea.

The only other thing I could think is that there's something going on with the connection to the pc?
Maybe try a different usb cable. Could be some interference or something?
Could also be the connection speed over usb? What is that speed set at? Maybe the controller is running out of commands to send and is stuttering because its waiting for more. That's a long shot, but I know I did have an issue with different versions of firmware on my k40 at one time with that.
 
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