Images squishing together

I have a 80w OMTech and a rotary made for it and I’m running the latest update from Lightburn. I set up my rotary and I’m sure I got my steps right. I set up a line that is the length of the circumference at a slight angle and had the laser etch it on a water bottle. The end meet where they should.

Now on to my problem. I’m etching a water bottle with an image and the image smushed by about 1/2”. I’m not sure if this is a hardware or software.
Speed: 300mm/s
Power max: 30%
Power min: 10%

Generally the rotary is placed in the machine for a scan, the major scanning is done with the X axes, meaning the Y axes moves slowly… by the dpi, which you didn’t mention.

If it’s a vector, that can change things also.

With it being ‘squished’ in the Y axes, I’d suspect your setup.

I would double check how it’s setup. If you did a line at an ‘angle’ it shouldn’t meet up in my imagination… or I guess I’m not following you there…

Here’s how I did mine. I’m assuming a wheel type rotary. If this is a scan, low power is not used.

Get the steps/rotation from the motor driver, read the switches

Then find it on the placard…

In my case it’s 2000 steps/rotation.

This is for the motor, a wheel type rotary usually has a gear ratio of motor rotations to one driving wheel rotation.

My PiBurn has a 2.5:1 ration to the wheel.

2.5 * 2000 = 5000. My wheel diameter is 62mm


That’s the basic idea.

How fast the head moves over the material is the ‘surface speed’, no matter if it’s the head moving or the material moving. The idea is the same speed with a rotary as with the table.

A wheel rotary has the driving wheel moving 10mm to move the material 10mm. With a chuck the surface speed is a function of the diameter.

Good luck


After doing a lot of looking and test I think I figured out what was wrong. I went back to the beginning and started measuring everything. I found that for the roller diameter I had 67.157mm, the measurements I after I rechecked it was 67.57mm. After that I fiddled with the step till it was right. Final step was 2960. Thank

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