Y axis movement jumping

I know this topic has had a lot of similar discussion. I have had my machine for right around a month now, and i had gotten it all tuned in and carving good. last about two weeks, it seems that every 2 or maybe 3 jobs i do the y axis starts to jump, or stutter in movement. one side looks to be slight delayed.

After a little while of using the jog feature it all aligns again. I have checked the tension on the belt as i thought maybe it was skipping teeth. I have adjusted the current settings to the motor, checked the v-wheels. Any other thoughts would be greatly appreciated.

You didn’t mention checking the wires/connections for your Y motors. Is it only happening when the machine is at a certain distance forward or back? Maybe when it’s stretched, the connection is pulling loose? Or maybe there’s a fault in the wire somewhere, so as it moves forward and back and the wire gets pushed and pulled, it’s reducing power?

Certainly sounds like one of the Y-steppers are not getting power or move in the wrong direction, and being “dragged behind”.

A stepper motor with 3 working wires (one not) will run as usual but direction will be lost, it will usually go in the direction of least resistance

This is my primary suspect :slight_smile:

Sorry for delay in response, it ha been a long day. So previously I have checked all of the connections for this issue, however, i do remember my Y2 connection being loose and re connecting it and seemed to work fin for a little while. I have never thought Of this as an issue since i did try to slight pull it out to see if that hat was causing it and it still worked fine, so i brushed it off until just now respondind to you mentioning it. I have not touched the machine since last mess up yesterday so this is something I’m ill take note of. Thank you!

Sorry for the delay in response, it has been a very long day. So are you referring to the backwards wiring of the stepper motors during the set up? This did confuse me not going to lie, and possibly could be wrong. However, would it still work for a few times then mess up? Or would this be issue all the time if the wiring was not correct?

If the motors were wired wrong, you would know it from the first cut. Your issue sounds like a loose wire, belt issue, or setting adjustment. Have you modified your original GRBL settings at all? Also, what size machine and did you buy it new?

@Mike_L So I have had many successful cuts, its like every 2- 3 cuts that’s this issue comes up and then after running the machine along the y axis goes back to normal. I have not adjusted the settings you GRBL settings, and I do plan to look for binding wiring that may be pulling tomorrow since i have not touched the machine since the last time it happened yesterday.

I bought the 1000mm platform and yes I bought it new.

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I’ve had this problem with my X-axis. Twice, it got twitchy on me and seemed to be running an obstacle course rather than cutting. Both times, wires had broken on the connection (due to a clamp that was conveniently located in the way of the wires. As was stated by many in this thread, I think any stuttering is most likely related to one or more connection not conducting.

Gerald you never commented on the carve result, it is messed up or fine?
Some designs have so many nodes that the machine seems to stall when cutting.
That is common in my experience but the carve is just as designed.

When the machines runs smoothly the carves come out fantastic. I haven’t ventured into any difficult designs yet just simple wording or shapes.

Yea I am going to go through the entire machine today and double check all connections and wiring. I know I have looked through it before but going to go through everything.

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So With the help of @Mike_L we decided to remove the belts and isolate the stepper motors. my Y1 motor was not making full rotations in comparison to the Y2 motor. Varified my wiring again, pulled the the connector from the stepper motor and off the back of the controller, cleaned everything with DeokIt Pro Gold Contact Cleaner, and reconnected. With the belts still disconnected used the Y axis jog movement and both motors moved in sync with each other. reconnected belts and moves smoothly along the y axis rails. hopefully this will be the end of the issue. Thank you all for the ideas and help.


I said that if one of the four motor wires have poor contact / bad joint somewhere the stepper will act as normal, except for direction which will be random/direction of least resistance.
So its possible that one wire had poor connection and initially move in the opposing direction before being overpowered by the other stepper. that would cause a “delayed/drag behind” behaviour.

The same behaviour can also be a loose pulley on one side, or one stepper may not get power and just behing tugged along.

Glad you got it fixed, whatever the reason was.

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I have had the same problem several times with all three axis. Usually it is a loose wire causing an intermittent connection. One time one of my y axis stepper motors had a bad winding or something that caused it to have more resistance in one pair of wires than the other, swapped it out and cured the problem