Wobbly lines on when both the x and y axis are moving at the same time(curved and diagonal line)

Main info:

*OMTECH 130W Blue&Grey Laser with Ruida controller - manual focus but automated bed
*Have used the machine for over 2 years with no issues.
*Wavy/wobbly lines started a few weeks ago out of nowhere - nothing was changed or adjusted it just suddenly started having messed up lines.
*Only happening when both the x and y axis is moving at the same time(diagonal and curved lines). If only 1 axis is moving (only side to side or up and down) those lines have no waves.

I am at a total loss about the wavy lines. I’ve spent the past week fiddling around with all different suggestions and scouring through Facebook posts, forum posts, and videos looking for a solution, but so far nothing has helped.

I’ve tried/checked:

*Cleaned and relubed all the rails
*Making sure mirrors are not loose(even replaced all 3 with American photonics bc they were looking a little worn)
*Checking that the lens tube is not wobbling(American photonics lens so it’s glued into the tube)
*Swapping out the lens tube just to double check that it wasn’t an issue
*Slowing down the speed(no significant change no matter how slow the movement is)
*I’ve adjusted the belt tension about a billion times on both the x and y axes to see if they were too loose or too tight - didn’t see any significant change in either direction
*changing PMW rising edge setting
*Scan offset test and adjustment
*Calibrating the x and y axes
*Realigned the mirrors 4 times now in the last 2 weeks and it’s cutting fine aside from the wobbles.
*Also tried lowering the max acceleration speed multiple times - no change.

I have checked every single thing I can think of and every single suggestion I’ve seen on Facebook and in forums and I have no idea where to go from here

It’s possible you’re running at a speed that makes the machinery resonate. Changing the speed 20% up or down might eliminate it (if it’s resonance).

I’m not certain this is relevant, but there is a Chordal motion associated with the belt tooth lifting off the belt pulleys. Russ Sadler found a cure for it by changing to a belt that is better at damping vibration and by reversing the belt so the chordal motion can’t interfere with the position of the engrave head.

It shows up very clearly as stripes or bands when engraving images.

Full analysis: RDWorks Learning Lab 83 Is this Curtains for ever - YouTube
Solution: RDWorks Learning Lab 121 Is this CURTAINS for CURTAINS - YouTube

Thank you! I’m scoring at the same speed I’ve been using for over 2 years, the wobbling started just a couple weeks ago. I did try lowering the speed multiple times, there’s no change to the wobbling(I normally score at 300mms, tried it at 100mms and 50mms with no change). The wobbles are also there when cutting(25-35 mms). They’re only occuring on lines that require the x and y axis to move in tandem(diagonals and curves). There is no noticable wobble to straight lines going side to side or up and down. I’m not having any issues with engraving, just scoring or cutting anything with a curved or diagonal line.


Did you find out what was causing it? It’s also happening to me but on 75º diagonal lines only.

I have the same issue with diagonal lines and curves only. Oddly enough I can print circles perfectly. I decided to do some test burns with hexagon shapes while adjusting acceleration. I thought that solved my problem until I tried my original projects with the same settings and it still happened.

Unfortunately I still haven’t figured out the issue. I plan on taking off all the belts to make sure there aren’t any loose screws or debris anywhere, but whether that will help remains to be seen.

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Im also having this problem. Im starting to believe this is more of a program problem vs mechanical with machines. Mirror mounts secure, lens secure, mirrors secure, rails cleaned and oiled and firmly secured, all motors and rotating parts oiled and not moving, lens tube and lense solid, laser tube secured, honeycomb and blades non wobbly, belts tightened (and losened during testing). AND this only happens during angles or circle scoring NOT horizontal or vertical. Tried various speed and power to fix, and fast, slow high low power no change. So in my mind going through all of the above, I do feel this is more a lightburn problem but am getting a new controller and will be testing if this occurs with RD Works. if no wobble, it will be associated with lightburn. but so many are experiencing this with different machines I personally belive it is a lightburn programing problem.

I thought it might be as well, but my controller works with other programs and I tested in RDWorks but still have the same issue, so for me it’s definitely not a lightburn problem.

interesting. Thanks so much for the reply. as Ive gone through everythign mechanical that I can think of… Have a high quality machine, and am out of ideas… thats why im getting a new controller sent out to try RD works and do a direct comparison…

You’re welcome. I have tried everything I can think of as well aside from trying a new connection type. I just recently tried switching from USB connection to Ethernet connection, but I can’t get lightning to communicate with the laser through Ethernet for some reason. My machine worked perfectly for 2 years prior to this and there where no changes made between it working great and then suddenly getting wobbles

Check for a loose lens. If not tightened it wobbles inside the head.

Sadly not the case. Lense, mirrors, mirror mounts, gantry, nozzle motors, belts, tube have all been tightened, oiled, triple checked etc. I’m defiant not the only one with this issue after checking so many things…I’m stumped.

How are you sending the files to your machine? I’ve checked everything I can think of mechanically as well as software. But recently my machine has started randomly changing some of the lines on projects I send over(a line will move out of position or something like a straight line will suddenly cut on a diagonal. It’s not happening every time, but randomly. My USB port on the laser had gotten slightly bent right after receiving it so this week’s shot in the dark is replacing the port and USB cord🤣 I doubt it would be causing the random wobbles, but I’m trying anything I possibly can think of.

I feel you. Just installed a new controller and tried RDWorks. Wobble is still there on the angle scores. So probably not lightburn. I use a usb cable. Could try a different one I guess… I’m stumped now that new controller didn’t fix it.

I don’t know if you’ve tried this… if for no other reason than to add it to the list of things it isn’t… when I have a job that runs more than a few minutes, I “send” it to the controller’s memory and run it from there. That way it eliminates most of the communications paths. Your issue still seems to be a mechanical problem, as Sherlock Holmes would say, “When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.” Your task is to eliminate the impossible.

Same here. My husband replaced the USB port and the cord last night but no change to the wobbles.

I’m definitely at the try anything and everything stage lol. Unfortunately I have tried sending it to the controller first with no change. I’ve also tried uploading the files to the controller via flash drive and replacing the USB port and cord. I’ve tried alternate software, cleaning and tightening literally everything, adjusting the belts, etc. My lens is glued in so it can’t be wobbling, but even if it was it wouldn’t make sense that it’s only wobbling on curved and diagonal lines. I’ve tried adjusting the vendor settings, slowing down the speed, changing the power. The wobbles are very slight so it’s not too noticable in cuts, but very noticable when scoring.

Which would infer that the X axis and Y axis steppers are being driven together. I’m spit-balling here, is there a common electrical connection between the two? Is it possible that the power supply is unable to provide enough current to both stepper drivers when they are running at the same time? Loose connection (power, signal)? I would at least wiggle the wires (if you haven’t already) at the controller and the stepper drivers and see if one of them may be a little loose.

So continuing to talk to my machine manufacturer, when you feel the machine, is it NOT wobbly on the x-y axis, but shaky on the angles? Going to discuss this further today. can report back if anything comes of it. As after changing controllers, AND going to RDWorks with no change it has to now be mechanical. as it isn’t lightburn settings in the controller…

Correct. I get no wobbles when only 1 axis is moving(straight horizontal or vertical lines), but when both axes are moving at the same time(curves and diagonal lines) there’s a slight wobble.