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docs: Update for latest changs to skew_correction

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Signed-off-by:  Eric Callahan <arksine.code@gmail.com>
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Arksine
2019-06-28 15:40:00 -04:00
committed by KevinOConnor
parent 0c379d060f
commit 57eb0e8975
4 changed files with 87 additions and 40 deletions
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docs/skew_correction.md
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@@ -1,6 +1,6 @@
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
that if your printer is significantly skewed it is strongly recommended to
first use mechanical means to get your printer as square as possible prior
to applying software based correction.
@@ -12,8 +12,9 @@ along the plane you want to correct. There is also a
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.
Make sure that no skew correction is applied during this print. You may
do this by either removing the [skew_correction] module from printer.cfg
or by issuing a `SET_SKEW CLEAR=1` gcode.
# Take your measurements
The [skew_correcton] module requires 3 measurements for each plane you want
@@ -23,18 +24,56 @@ AD do not include the flats on the corners that some test objects provide.
![skew_lengths](img/skew_lengths.png)
# 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:
# Configure your skew
Make sure [skew_correction] is in printer.cfg. You may now use the `SET_SKEW`
gcode to configure skew_correcton. For example, if your measured lengths
along XY are as follows:
```
[skew_correction]
xy_ac_length: 140.4
xy_bd_length: 142.8
xy_ad_length: 99.8
Length AC = 140.4
Length BD = 142.8
Length AD = 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:
`SET_SKEW` can be used to configure skew correction for the XY plane.
```
SET_SKEW XY=140.4,142.8,99.8
```
You may also add measurements for XZ and YZ to the gcode:
```
SET_SKEW XY=140.4,142.8,99.8 XZ=141.6,141.4,99.8 YZ=142.4,140.5,99.5
```
The [skew_correction] module also supports profile management in a manner
similar to [bed_mesh]. After setting skew using the `SET_SKEW` gcode,
you may use the `SKEW_PROFILE` gcode to save it:
```
SKEW_PROFILE SAVE=my_skew_profile
```
After this command you will be prompted to issue a `SAVE_CONFIG` gcode to
save the profile to persistent storage. If no profile is named
`my_skew_profile` then a new profile will be created. If the named profile
exists it will be overwritten.
Once you have a saved profile, you may load it:
```
SKEW_PROFILE LOAD=my_skew_profile
```
It is also possible to remove an old or out of date profile:
```
SKEW_PROFILE REMOVE=my_skew_profile
```
After removing a profile you will be prompted to issue a `SAVE_CONFIG` to
make this change persist.
# Verifying your correction
After skew_correction has been configured you may reprint the calibration
part with correction enabled. Use the following gcode to check your
skew on each plane. The results should be lower than those reported via
`GET_CURRENT_SKEW`.
```
CALC_MEASURED_SKEW AC=<ac_length> BD=<bd_length> AD=<ad_length>
@@ -42,11 +81,13 @@ 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.
Due to the nature of skew correction it is recommended to configure skew
in your start gcode, after homing and any kind of movement that travels
near the edge of the print area such as a purge or nozzle wipe. You may
use use the `SET_SKEW` or `SKEW_PROFILE` gcodes to accomplish this. It is
also recommended to issue a `SET_SKEW CLEAR=1` in your end gcode.
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].
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].