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E Step Calibration  

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thani
(@thani)
New Member
E Step Calibration

Hi everybody,

my printer has some problems with PETG stringing.
So I was trying some different settings for retraction and linear advance K factor setting, but could not achieve real improvments.
I found the extruder calibration manual at this website https://mattshub.com/2017/04/19/extruder-calibration/
and decided to give it a try.

The command should extrude 100mm of material, but my printer ended up with 96mm.
This results in a new E Step value of 291.6 st/mm instead of the default 280 st/mm.

I understand this calibration makes sense for a custom printer, but the prusa printers share drivers, steppers, extruder etc. so the default value should work.
Anybody did this calibration and had a similar experience ?

Posted : 21/10/2018 11:24 pm
bobstro
(@bobstro)
Illustrious Member
Re: E Step Calibration


[...] I understand this calibration makes sense for a custom printer, but the prusa printers share drivers, steppers, extruder etc. so the default value should work.
There will always be small mechanical differences between devices and individual components. You can probably buy parts with extremely high tolerances, but you should expect to pay accordingly. As-is, parts with less precision can be used to assemble a relatively low-cost device that is easy enough to calibrate sufficiently for our purposes.

I went through the procedure and the existing setting was nearly spot-on. Things may drift over time with motor efficiency and a host of other factors.

There will also be differences between filaments. Having done the hardware-level calibration described on Matt's page, I do additional tweaking per-filament using the procedure Prusa provides.

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 : 22/10/2018 12:18 am
surfgeorge
(@surfgeorge)
Estimable Member
Re: E Step Calibration

Maybe check your bondtech idler tension.
It could be that if you tighten it too much the effective diameter of the hobbed gear becomes smaller, but I am not sure.
Anyway, the idler tension seems to be an important parameter for good and consistent results.

Rule of thumb: just enough that it does not slip. Depends also on filament

(I used to have it too tight, and the teeth really bit into the filament. Now it's still leaving marks, but only small ones)

Posted : 22/10/2018 8:56 am
Dutchy
(@dutchy)
Eminent Member
Re: E Step Calibration

When I send the extrude command using octoprint it returns a filament sensor message, I will try to turn the sensor off and see if it makes a difference.
It looks like the printer wants to check if there is filament loaded or not before executing the extrude command.

Posted : 22/10/2018 11:22 am
Dutchy
(@dutchy)
Eminent Member
Re: E Step Calibration

Just tried again.

Turned the filament sensor off because I though this was causing a pause.

E steps 282.5 send G1 E100 F100 with a knife mark at 120mm then I had 18.8mm left so 282.5/101.2*100=279.15
Then send G1 E100 F100 again and now 33.00mm left

Then tried it again with M92 E279 and 11.2mm left so somewhere there's a major issue going on. Gear doesn't skip, Using PETF at 230c

Posted : 22/10/2018 4:02 pm
Alphaspector
(@alphaspector)
Member
RE: E Step Calibration

I am trying to change the e steps on the printer but can not find any setting to do so. I did the formula and found that I am under extruding. I want to change the steps and not just bump the extrusion multiplier. I have a mk3s+

Posted : 24/07/2024 11:42 pm
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