Y-axis problems

Hi. I have recently installed a C3d laser board and LCD display board in my K40. Initially all seemed well. However, it turns out that all vertical dimensions (i.e. Y-axis) are enlarged by about 12%. Circles turn out as ovals and squares turn out as rectangles. Also, the Y-axis randomly skips steps. I have checked and made sure that the gantry runs smoothly with no rough spots or resistance. It appears not to be the belt slipping notches but rather the stepper motor not moving to the next location. I use the high quality usb cable supplied with the kit and have not made any other modifications to the unit. Any help would be appreciated.


Pictures of the install and a video of what’s happening would all help here for us to help diagnose the problems…

I would start by sorting out the skipping, as I believe that or moving too fast might be causing your Y axis elongation issues.

I would recommend this post to get started: Best Configuration settings?

In particular:

Line 6 default_seek_rate 24000
Lower this substantially - perhaps to 9000

Line 21 acceleration 2500
Lower to 1000

Lines 51
beta_current 0.6
Increase in 0.2 increments until the skipping stops.

Hi Eamonn,

Thanks for your reply. Excuse my ignorance but I assume that these lines are from a configuration file. am I correct? Are they on the SD card? I guess I need to get hold of some kind of reader.

I do not believe the elongation is related to the skipping of steps because the skipping makes a noise and the elongation is always there, even if there is no skipping noise. Also, if they were related, circles would be squashed in steps, not perfectly smoothly elongated. Anyway, the skipping of steps is my greatest concern as it is random and cannot be compensated for. I can always reduce all vertical dimensions to 87% to overcome to Y axis elongation. Anyway. Thanks for your help so far.

I had a y axis elongation problem like you and found that the “use rotary” box
had been checked in lightburn. Removed the check and everything is back
to normal. Just a thought

Thanks for your response. However, my problem was solved when I increased the current to the stepper motor somewhat by editing the config file.