2.2 KiB
Software based skew correction can help resolve dimensional inaccuracies resulting from a printer assembly that is not perfectly square. Note that if your printer is significantly skewed it is strongy recommended to first use mechanical means to get your printer as square as possible prior to applying software based correction.
Print a Calibration Object
The first step in correcting skew is to print a calibration object along the plane you want to correct. There is also a calibration object that includes all planes in one model. You want the object oriented so that corner A is toward the origin of the plane.
Make sure that the [skew_correction] module is not enabled in printer.cfg prior to printing the calibration part.
Take your measurements
The [skew_correcton] module requires 3 measurements for each plane you want to correct; the length from Corner A to Corner C, the length from Corner B to Corner D, and the length from corner A to corner D. When measuring length AD do not include the flats on the corners that some test objects provide.
Update printer.cfg
Enter your lengths for the calibration print corresponding to the correct plane under the [skew_correction] section in printer.cfg, for example:
[skew_correction]
xy_ac_length: 140.4
xy_bd_length: 142.8
xy_ad_length: 99.8
Restart your printer. If desired, you can reprint the calibration part with skew correction enabled. The following gcode can be used to calculate skew of a single plane and output the results:
CALC_MEASURED_SKEW AC=<ac_length> BD=<bd_length> AD=<ad_length>
Caveats
When using the [skew_correction] module it is suggested to home all axes before attempting a move. Homing a single axis to move could result in a correction along the x and/or y axis, potentially leading to a homing error.
It is also important to keep in mind that it is possible for [skew_correction] to generate a correction that moves the tool beyond the printer's boundries on the X and/or Y axes. It is recommended to arrange parts away from the edges when using [skew_correction].