Hi i am using a cohesion 3d board on my k40 laser and when i cut a square of 25mm x 25mm the x axis is 25mm but the y axis is 24mm and also when i cut circles they are more oval than circle. is there anyway i can change the settings or calibrate the motors ??. ps i am using lightburn and their calibration doesnt work on smoothieware
Post your current configuration here, between lines with three open single quote characters. It should look like this:
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your configuration
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Where would.i find that please ?? Or how would i get it ??
I don’t need anything here. I’m just the site admin trying to help you actually provide information that would let others with more knowledge of smoothieware help.
I suggested that you paste the whole configuration. Not sure why you posted a screenshot of a tiny piece of it instead. 
Since you have a CO2 laser which uses lots of mirrors to direct the beam and you are looking at 1mm of offset then I would first check all of your belts and drive units(motors, couplers, drive gear, etc) and then I would look at bed level.
Only after looking at and eliminating all mechanical options would I then start changing the firmware to fix the problem.
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If it’s a K40, I strongly suspect this is just a mirror alignment/belt tightening issue (assuming you got the right steps/mm from a trusted source)
One thing you can do is instead of testing with the laser, attach a pen to the head, and move that over a sheet of paper/cardboard, and measure that instead of measuring laser cuts, that way you’ll exclude the laser/mirror alignment issues from the equation.
Also, I recommend you try to draw a rectangle the same size as your work area, and then measure what was actually drawn.
Also, give us the full configuration, follow Michael’s instructions (no screenshots, copy the full file, do it in the format he recommended) they are not complicated, and they are necessary for us to help you.
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One more possibility on the physical side besides belts or mirrors being loose: If it was acquired used and someone had replaced belts, if they replaced one belt with the typical GT-2 belts used on 3d printers, it will also do this. The K40 Intro in the header has links to the correct kind of belt and more information on this. If the pen drawing approach shows the same problem, then it’s fairly likely.
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