X-Axis Compensation  

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james.j13
(@james-j13)
Active Member

My X-Axis is printing slightly smaller that it should.  I would like to scale it up by ~0.8%.  Are there any options for scaling just the X-Axis without scaling the Y-Axis at the same time?

Posted : 21/09/2020 12:12 am
joan.t
(@joantabb)
Veteran Member Moderator

is your error comparable to model size? if you double the model size do you get double the error?
is the error ten times as large on a 100mm model compared to a 10mm model, and is it 20 times as large on a 200mm model? 

If the error is the same size issespective of model dimensions, the cause is probably in the motion, not the control 

you can scale STL's on the individual axis, in slicer, 

you can alter the steps per milimeter for each axis motor, on the printer. 

however if your X belt is loose or the X bearings are tight, or your X axis toothed wheel grub screw is a little loose, these could be contributory factors. 

Have you lubed your linear bearings?
have you tried moving the X carriage  when the printer is idle? to see if it moves freely? and checked that the Grub screws are tight (Don't use a ball end of an allen wrench, use the  normal type... It reaches into the bottom of the hex recess and doesn't split the grub screw)

Regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 21/09/2020 12:53 am
james.j13
(@james-j13)
Active Member

Hi Joan, it does scale linearly with size.  Regarding the first of the two methods you suggest, scaling the STLs, that would need to be done on the parts every time they are imported into the slicer, correct?  As for the second method, altering the steps/mm on the printer, will that setting be preserved after power cycling the printer?  And after firmware upgrades?  Neither of those seem terribly difficult, but would like to go with the lazier option 🙂

Posted : 21/09/2020 2:44 am
james.j13
(@james-j13)
Active Member

Bump!

Posted : 23/09/2020 10:03 am
james.j13
(@james-j13)
Active Member

Bump!

Posted : 26/09/2020 10:36 pm
Karl Herbert
(@karl-herbert)
Famed Member

@james-j13

What are you trying to tell us??

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 26/09/2020 11:29 pm
james.j13
(@james-j13)
Active Member

@karl-herbert

I was trying to get a reply to this comment:

"Hi Joan, it does scale linearly with size.  Regarding the first of the two methods you suggest, scaling the STLs, that would need to be done on the parts every time they are imported into the slicer, correct?  As for the second method, altering the steps/mm on the printer, will that setting be preserved after power cycling the printer?  And after firmware upgrades?  Neither of those seem terribly difficult, but would like to go with the lazier option 🙂"

Posted : 27/09/2020 5:20 am
james.j13
(@james-j13)
Active Member

@karl-herbert

I have something very strange going on.  I am trying to print a very simple gage that needs to be accurate within 0.2mm.  It has a shape like this " [ ", so nothing fancy or complicated.  The internal gap I measure between the horizontal features " - ",  is 131.0mm, but the designed value is 132.0mm.  I have checked my CAD file and STL, which are correct, and printed some other parts but they measure more accurately - within 0.5mm at that length.  The shape of the other parts is like this " | ".  It is a bit suspicious that the " [ " shape is off by almost exactly 2X compared to the " | " shape, but I haven't figured out what could cause that to happen.  Open to any thoughts or tests to run.

This post was modified 3 weeks ago by james.j13
Posted : 03/10/2020 6:51 am
Karl Herbert
(@karl-herbert)
Famed Member

@james-j13

If you want to print dimensionally accurate parts, some adjustments to the mechanics and the slicer are necessary. Important parameters are:

- Check mechanics - no loose pulleys, correct belt tension, smooth running axles
- Calibrate esteps X/Y/E
- Slicer settings - multiplication factor, filament diameter, flow,

But keep in mind that the printer is not a precision machine and you must be satisfied if you get deviations in the range of 0.5%. Anything that is more accurate is already very good.
Everything else you have to correct or adjust in CAD and reprint.

Good luck!

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 04/10/2020 1:15 pm
peter.m26
(@peter-m26)
Honorable Member

Check if gears are gripping good on the filament.

Check grub screws, if nothing is loose.

Check the whole printer for loose parts , screws ......

Check if nozzle is not partially clogged.

To much tension on belts is also not good.

Search for a test object where you can test print on, and adjust settings.

 

Posted : 04/10/2020 1:55 pm
Karl Herbert
(@karl-herbert)
Famed Member

The famous test cube 20x20x20 is not sufficient enough for calibration. Even if the dimensional accuracy of the cube is good, this does not necessarily mean that e.g. a 150mm object is true to size.
Just print test objects in different dimensions and find as good a match as possible with the above mentioned parameters.
Every now and then, especially with holes, I adjust the CAD data according to the print result and print again. Mostly the holes are printed too small.

 
This post was modified 3 weeks ago by Karl Herbert
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 04/10/2020 2:19 pm
james.j13
(@james-j13)
Active Member

@karl-herbert

-In terms of mechanics, the printer is in good order - all relevant fasteners have been checked, belt calibration centered within the recommended limits, lubrication where appropriate, and extruder tensioner properly adjusted.

-Is there a preferred method for estep calibration that doesn't require editing gcode for every print?

-The diameter, and extrusion multiplier are pretty easy to find in the Filament Settings.  Those have been tuned, but is there a separate one for "flow", and if so, how is that different than extrusion multiplier?

-The scale factors for XYZ in Object Manipulation looks really straight forward and probably will fix this.  Question though, is there a way to save the axis scaling such that it won't reset automatically?

Posted : 05/10/2020 3:53 am
Karl Herbert
(@karl-herbert)
Famed Member

@james-j13

- you can also fix the esteps values in the firmware

- regarding flow and extrusion multiplier -> https://help.prusa3d.com/en/article/extrusion-multiplier-calibration_2257

- esteps calibration -> https://mattshub.com/blogs/blog/extruder-calibration and

https://www.3dhubs.com/talk/t/howto-calibrate-tune-and-fine-tune-your-printer-and-filament/5695 and

http://print.theporto.com/posts/how-to-calibrate-your-3d-printer-for-accurate-printing/  

- I would not specify the scaling but rather adjust it individually/print part (if necessary). But I have never used this option.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 05/10/2020 3:04 pm
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