Projects made slightly smaller

Hello - I created a fitting for the end of a fluorescent light and it was 75.11mm wide on the Eazydraw software, and then exported as a pdf, and finally opened in Lightburn where it measured 75.05mm.
The project completed satisfactorily on a 80w Chinese laser using the Ruida controller, but the finished product was 74.76mm and therefore not quite the right size. Is there a way to “tune” either Lightburn or Ruida to ensure drawings are replicated accurately?

If you cut a 500 mm by 500 mm square out of taped together sheets of paper, is each side exactly 500 mm long and do both diagonals measure the exact same length?

good point Doug - I suspect not, but I’ll try that to check if the machine is doing parallelograms…I had a size problem with a previous laser, but the Mach3 software had an adjustment called “steps per” which could be adjusted until perfect size replication was achieved. I assumed Lightburn and or Ruida would have this factory set…

This might help. Configuring A Ruida - LightBurn Software Documentation

Step Length Calibration

The next part is figuring out how far the laser moves when you tell it to, and how far off it is. The controller needs to know how far a single step moves when it sends a step pulse to the motors so it can translate real measurements into the proper number of steps.

Please let us know how you progress. :slight_smile:

Thanks Rick - I found the step - length for X and Y axes, and also the error I need to correct. The test circles and squares I cut out are 99.4% of the size they should be. I plan to increase each step size by a factor of 1.006 to see if that helps. I assume I’ll have to save to the relevant file and switch the controller off and then on to load the new values? Thanks again!

Hello again - if in doubt read the instructions etc - I have reduced the step size, and all is correct and items are pretty much exactly the right size! Thanks very much for your help!

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