53 lines
2.2 KiB
Markdown
53 lines
2.2 KiB
Markdown
Software based skew correction can help resolve dimensional inaccuracies
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resulting from a printer assembly that is not perfectly square. Note
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that if your printer is significantly skewed it is strongy recommended to
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first use mechanical means to get your printer as square as possible prior
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to applying software based correction.
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# Print a Calibration Object
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The first step in correcting skew is to print a
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[calibration object](https://www.thingiverse.com/thing:2563185/files)
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along the plane you want to correct. There is also a
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[calibration object](https://www.thingiverse.com/thing:2972743)
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that includes all planes in one model. You want the object oriented
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so that corner A is toward the origin of the plane.
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Make sure that the [skew_correction] module is not enabled in printer.cfg
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prior to printing the calibration part.
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# Take your measurements
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The [skew_correcton] module requires 3 measurements for each plane you want
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to correct; the length from Corner A to Corner C, the length from Corner B
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to Corner D, and the length from corner A to corner D. When measuring length
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AD do not include the flats on the corners that some test objects provide.
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# Update printer.cfg
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Enter your lengths for the calibration print corresponding to the correct
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plane under the [skew_correction] section in printer.cfg, for example:
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```
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[skew_correction]
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xy_ac_length: 140.4
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xy_bd_length: 142.8
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xy_ad_length: 99.8
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```
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Restart your printer. If desired, you can reprint the calibration part
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with skew correction enabled. The following gcode can be used to calculate
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skew of a single plane and output the results:
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```
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CALC_MEASURED_SKEW AC=<ac_length> BD=<bd_length> AD=<ad_length>
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```
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# Caveats
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When using the [skew_correction] module it is suggested to home all axes
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before attempting a move. Homing a single axis to move could result in a
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correction along the x and/or y axis, potentially leading to a homing error.
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It is also important to keep in mind that it is possible for [skew_correction]
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to generate a correction that moves the tool beyond the printer's boundries
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on the X and/or Y axes. It is recommended to arrange parts away from the
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edges when using [skew_correction].
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