What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?
 
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What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?  

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dimprov
(@dimprov)
Noble Member
What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

I notice these possible settings under the new 3.3.0 firmware. What do these settings do, and when should I enable them? The default seems to be disabled.

Posted : 05/07/2018 1:45 pm
imod.systems
(@imod-systems)
Honorable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

E correct is fro extruder linearity correction to reduce the moire effect of the trinamic drivers: https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration

Not sure what the other options do but I'm curious.

Posted : 05/07/2018 2:04 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

Weird to release 3 new features but not tell anyone what they do. 🙄

Posted : 06/07/2018 8:36 pm
imod.systems
(@imod-systems)
Honorable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

Yep, that's Prusa's stellar communication for you.

Posted : 06/07/2018 9:02 pm
Erik
 Erik
(@erik-3)
Estimable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?


Yep, that's Prusa's stellar communication for you.

They may have just released all of the features as a set and only explained the E Correction for now, as that was the important part they wanted out. They published the use and instructions for configuring it.

Posted : 07/07/2018 1:33 am
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?



Yep, that's Prusa's stellar communication for you.

They may have just released all of the features as a set and only explained the E Correction for now, as that was the important part they wanted out. They published the use and instructions for configuring it.

I'm pretty sure e-correct was in earlier firmware releases. AFAIK, only x,y, and z are new.

Posted : 07/07/2018 1:44 am
Vincenzo.c3
(@vincenzo-c3)
Trusted Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

Most likely I'll be wrong, maybe we can set from the menu the parameters obtained from the Step/mm calibration and calibrations of the various axes without storing them in the eeprom or without using the M92 command in the Gcode start.

Posted : 07/07/2018 8:28 pm
ClassicGOD
(@classicgod)
Eminent Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

From: https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration
Linearity correction is based on Trinamic stepper driver feature that allows definition of custom current-waveform. Default trinamic waveform is sine function, but real waveform can be litlebit different and depends on used stepper motor type. Also motors of same type can have different waveforms. Bigest distortion appears when the wave crossing zero point (around zero point), so the original sine wave is modified using power function to eliminate this distortion.

My understating is: Trinamic drivers have a parameter that can be set that you can use to tune the microstepping of the motor creating more uniform microsteps. Uneven microsteps and motor snapping to the full steps when it shouldn't can create artifacts usually called moire artifacts if the extruder motor is responsible or microstepping artifacts for X and Y axis and in severe cases can caouse z banding on Z axis.

This is most noticeable in case of extruder motor (that is why it was enabled first) but since it does not require any changes in firmware other than enabling a user to set the value there is no reason not to enable this option for other axis. Those settings should allow slight improvements to the surface finish.

I don't think anyone has created a gcode test those settings for other axis but I hope someone does soon.

PS. From the looks of it it can be changed in gcode using 'TMC_SET_STEP_E' command foe E axis (as you can see this is not a standard gcode command), I assume there are TMC_SET_STEP_X, TMC_SET_STEP_Y and TMC_SET_STEP_Z command as well.

If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.

Posted : 07/07/2018 10:10 pm
Tiago
(@tiago)
Reputable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

That looks like X, Y, Z and E steps.
For example if you move X axis 100mm but in fact it only move 99.5mm you can calibrate the steps to match the expected value with the real value.
E-steps tune can also be set on slic3r, the extrusion multiplier will do same effect i think

Formula: https://jscalc.io/calc/tHjfIiKMKjDF42Hg

Posted : 07/07/2018 11:03 pm
jonnieZG
(@jonniezg)
Trusted Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?


For example if you move X axis 100mm but in fact it only move 99.5mm you can calibrate the steps to match the expected value with the real value.
E-steps tune can also be set on slic3r, the extrusion multiplier will do same effect i think

Formula: https://jscalc.io/calc/tHjfIiKMKjDF42Hg

You are right about the purpose of these options, but I think that choosing a right value is not that simple. We are still waiting for the right procedure, like the one for setting a right E-correct value. Until that, sit tight and don't fiddle with it unless you are absolutely sure about what you are doing. You won't break anything, but you are likely to make it worse.

Posted : 20/07/2018 8:59 am
themzlab
(@themzlab)
Estimable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?



For example if you move X axis 100mm but in fact it only move 99.5mm you can calibrate the steps to match the expected value with the real value.
E-steps tune can also be set on slic3r, the extrusion multiplier will do same effect i think

Formula: https://jscalc.io/calc/tHjfIiKMKjDF42Hg

You are right about the purpose of these options, but I think that choosing a right value is not that simple. We are still waiting for the right procedure, like the one for setting a right E-correct value. Until that, sit tight and don't fiddle with it unless you are absolutely sure about what you are doing. You won't break anything, but you are likely to make it worse.

No, this is not it. I can see why a person would think that absent of other information but this member (following quote) does have the right information.


From: https://github.com/prusa3d/Prusa-Firmware/wiki/Extruder-linearity-correction-calibration
Linearity correction is based on Trinamic stepper driver feature that allows definition of custom current-waveform. ...

Notice that the setting is OFF and then starts at 1.03 going up to 1.20. this is not a +/- adjustment for any length corrections.

the related information for the extruder correction is here

https://help.prusa3d.com/l/en/article/p2xdpg0ul8-extruder-linearity-correction-calibration

What is curious is that Prusa claims most machines extruders will be best with a value around 1.10. I have run the test part and can see differences but I would be hard-pressed to choose any one view over another one for total quality. There isn't a formal test prescribed for the other axes but the setting is there for people who want it, I guess..?

if it is true that 1.1 is a good correction I would think all axes should be set to that.

Posted : 20/07/2018 12:45 pm
Tiago
(@tiago)
Reputable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?


You are right about the purpose of these options, but I think that choosing a right value is not that simple. We are still waiting for the right procedure, like the one for setting a right E-correct value. Until that, sit tight and don't fiddle with it unless you are absolutely sure about what you are doing. You won't break anything, but you are likely to make it worse.

Formula can be different for these drivers i don't know.
Nothing wrong about change the value and try, you can always revert to stock. We learn by doing and observe the result, it's our nature 🙂

Posted : 20/07/2018 3:48 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

This is becoming a bit surreal. 🙄 What is the official procedure to find out what x,y, and z correct officially do, and find out what the appropriate guidance is? Do we have to submit a bug report on github or something?

Or, maybe one of the moderators has some pull and can inquire on our behalf?

Posted : 20/07/2018 8:40 pm
bobstro
(@bobstro)
Illustrious Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?


This is becoming a bit surreal. 🙄 What is the official procedure to find out what x,y, and z correct officially do, and find out what the appropriate guidance is? Do we have to submit a bug report on github or something?
You don't have to do anything. They could turn out to be diagnostic or test settings. If you're able to print now, I wouldn't feel compelled to go twiddling knobs without knowing what they do.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 20/07/2018 8:58 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?

Of course. However, the motivation for finding out now is so that *if* in the future I do encounter problems which can be solved with a few settings, then I won't hit a wall but instead I'll already know what to do when they occur.

Posted : 20/07/2018 9:51 pm
themzlab
(@themzlab)
Estimable Member
Re: What do "x-correct" "y-correct" "z-correct" "e-correct" do, and should I enable them?


This is becoming a bit surreal. 🙄 What is the official procedure to find out what x,y, and z correct officially do, and find out what the appropriate guidance is? Do we have to submit a bug report on github or something?

Or, maybe one of the moderators has some pull and can inquire on our behalf?

x, y and z factors do the same thing as the one for the extruder except that obviously they apply to the other motors. the procedure for determining the E-value is in the link above and it is *official* as it comes from Prusa through the video and the blog.

The tweak is very, very minor and is so subtle that it is hard to pick up even on the extruder results so it must be very minor on the other axes. I think it would be a waste to try but if you do, why not try 1.10 for all since that is what Prusa thinks is the nominal.

I left my X Y and Z alone. I have set the E to 1.03 and then to 1.1.

The setting may help people that like to experiment with those settings as it avoids them having to compile special versions of the firmware.

This is my understanding of the situation, and it's always possible I am wrong. This adjustment (correction) factor came about because of the thing called "inconsistent extrusion" that sometimes causes a basket-weave look under certain lighting conditions.

Posted : 21/07/2018 2:00 am
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