Issues with calibrating extruder E steps
Hello all,
I've done this before, without as much problem as I'm having now, first of all. That was on some previous firmware, months ago. I've recently been having issues with extrusion though, so I thought that I would revisit this ( https://mattshub.com/2017/04/19/extruder-calibration/ ) as I saw that it was back to the default 161.30 value.
After some tests, extruding is just wildly inconsistent for me, so I'm sure that I'm doing something wrong...
Here's some notes that I took, following Matt's extruder calibration steps. I am using the Prusa i3 MK2, with the latest firmware (3.1.0). XYZ calibration is good, PINDA calibration and temp calibrations have been run already. This was done with PETG loaded at 240c (prints just fine at that temp, even at 220c it extrudes alright), using OctoPi to send the commands in the terminal:
M502 ;Load defaults
M500 ;Save defaults
M503 ;Read settings
Recv: echo: M92 X100.00 Y100.00 Z400.00 E161.30
M83 ;Set extruder relative mode
;Mark filament at 120mm from where it enters the extruder
G1 E100 F100 ;Send 100mm of filament
Measured the 120mm mark, after extruding 100mm: 29.38mm to 120mm mark
120 - 29.38 = 90.62
100 / 90.62 = 1.1035
161.30 * 1.1035 = 177.99 (or 16130 / 90.62 = 177.99)
M92 E177.99 ;Set new E steps, from previous values/ maths
M503 ;Double check the settings
Recv: echo: M92 X100.00 Y100.00 Z400.00 E177.99
M83 ;Settings are fine, set relative mode again
;Mark filament at 120mm from where it enters the extruder
G1 E100 F100 ;Send 100mm of filament
Measured the 120mm mark, after extruding 100mm: .46mm to 120mm mark
120 - 0.46 = 119.54 ;Almost lost my 120mm mark to the filament hole on the extruder
100 / 119.54 = 0.8365
177.99 * 0.8365 = 148.89 ;This is waaay too low, below the original 161.30, which was under extruding.
M92 E148.89 ;Set new E step
M503 ;Check settings
Recv: echo: M92 X100.00 Y100.00 Z400.00 E148.89
M83 ;Settings are fine, set relative mode again
;Mark filament at 120mm from where it enters the extruder
G1 E100 F100 ;Send 100mm of filament
Measured the 120mm mark, after extruding 100mm: 85.29 to 120mm mark
120 - 85.29 = 34.71
100 / 34.71 = 2.88
148.89 * 2.88 = 428.8 ;This is absurdly high, not going to send that.
Some other values that I got:
E161.30, marked 120mm, measured 28.37mm (120 - 28.37 = 91.63). 16130 / 91.63 = 176.03
E176.03, marked 120mm, measured 2.7mm (120 - 2.7 = 117.3). 17603 / 117.3 = 150.06 ;Not going to work
E161.30, marked 120mm, measured 32.70mm (120 - 32.70 = 87.3). 16130 / 87.3 = 184.77
E184.77, couldn't measure result
E161.30, marked 120mm, measured 30.35mm (120 - 30.35 = 89.65). 16130 / 89.65 = 179.92
Didn't record measured, because whatever it gave was again something unresonable
I just can't seem to get any type of consistency here, and I don't know why. Am I doing something wrong?
Here's my full M503 default output:
Send: M503
Recv: echo:Steps per unit:
Recv: echo: M92 X100.00 Y100.00 Z400.00 E161.30
Recv: echo:Maximum feedrates (mm/s):
Recv: echo: M203 X500.00 Y500.00 Z12.00 E120.00
Recv: echo:Maximum Acceleration (mm/s2):
Recv: echo: M201 X9000 Y9000 Z500 E10000
Recv: echo:Acceleration: S=acceleration, T=retract acceleration
Recv: echo: M204 S1500.00 T1500.00
Recv: echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
Recv: echo: M205 S0.00 T0.00 B20000 X10.00 Y10.00 Z0.20 E2.50
Recv: echo:Home offset (mm):
Recv: echo: M206 X0.00 Y0.00 Z0.00
Recv: echo:PID settings:
Recv: echo: M301 P40.93 I4.88 D86.08
Recv: echo:PID heatbed settings:
Recv: echo: M304 P126.13 I4.30 D924.76
Recv: echo:Retract: S=Length (mm) F:Speed (mm/m) Z: ZLift (mm)
Recv: echo: M207 S3.00 F2700.00 Z0.00
Recv: echo:Recover: S=Extra length (mm) F:Speed (mm/m)
Recv: echo: M208 S0.00 F480.00
Recv: echo:Auto-Retract: S=0 to disable, 1 to interpret extrude-only moves as retracts or recoveries
Recv: echo: M209 S0
Recv: echo:Filament settings: Disabled
Thanks.
Re: Issues with calibrating extruder E steps
Which software version are you using? There was a glitch where e-steps was not saved correctly.
Bill
Tagaytay City, Philippines
Founder member of Philippines Prusa Printer Owners FB Group
Sponsor Pillars of God Academy in Bacoor
Re: Issues with calibrating extruder E steps
Prusa i3 MK2, with the latest firmware (3.1.0). Even if it's not saved, I double checked before extruding that it was still set. It's only reset when the printer is power cycled, right?
I also set the E steps, ran M500, M503, and it did show the updated value, so I don't think that's affecting it. I also just don't seem to get consistent results extruding with the default 161.30
Re: Issues with calibrating extruder E steps
Your procedure looks right.
I also just don't seem to get consistent results extruding with the default 161.30
You'll need to investigate the cause of this.
Is your filament feed free of binding? Hobbed pulley clean and set screw (grub screw) tight? Is your extruder temperature consistent? Perhaps you have a partial nozzle clog.
-Kevin
Re: Issues with calibrating extruder E steps
The extruding seems fine. No skipping, no temp drops. As mentioned, even extruding at 220c doesn't give me any problems. I did try and hold the filament to see if I could get it to skip (in case it wasn't tight enough), and even gripping the filament between my fingers, it didn't skip at all.
Pulley is clean, grub screw isn't loose, temperature is constant 240c (maybe occasionally drops to 239c).
The nozzle that I'm using is pretty new (less than 10 hours print time), and is the CleanTip Stainless Steel Nozzle (0.40mm) from MatterHackers. Extrudes the filament straight/ smoothly, so it's not blocked.
It's really a mystery to me at the moment
Re: Issues with calibrating extruder E steps
Have you found the problem? after i changed my nozzle to Micro Swiss, i am getting the same issue as you are.
i've chnaged it back to the original nozzle, but still cant calibrate the e steps
Re: Issues with calibrating extruder E steps
Hello Andre,
I have no found the issue, and I haven't really revisited this much since my post here. Sorry I don't have more information for you.
Re: Issues with calibrating extruder E steps
First things first....
In my opinion calibrating e-steps is fruiteless because all other parts of the system must be perfect too. but they're not. e-steps is a static number for the stepper but the flow will never be the same because...
1. Idler tension
2. Different filaments will squash or grip slightly more into the teeth changing the effective gear diameter.
3. Speed - extrusion speed affects it slightly too, probably the same reasons above in #2.
i would use the calculated theoretical value, steps per mm/gear size. done.
Then use other means like flow rate to adjust per-filament.... you'll never get perfect. you put PETG in there now but if you did get consistent results and then switch to PLA they'll be off again...
However.... to see if you have an actual problem... do the test multiple times with the same steps per/mm. if it always comes out the same or very close then there is no problems with hardware or nozzle. it might be less inconsistent with different idler tension or swapping to PLA or both....
if it's different, test and see if it changes in silent vs normal power mode. in one instance my results got more accurate to +/- 0.5mm after adjusting extruder current. (not on an MK2/3 though...)
you could always extrude with no nozzle, and no heat so it just goes right through the hotend but i don't think that's possible with prusa without firmware changes.
RE: Issues with calibrating extruder E steps
Just tried to calibrate e-steps on my mk2.5s today (again). There is definitely a bug in the firmware. Changing the e value from 133 to 140 (not much calculating, change it a little bit and extrude) shows values which absolutely do not correspond to the extruded length. The length of extruded filament goes up AND down when raising the value.
This problem occured a year or two ago when I tried to calibrate when changing the extruder to bondtech gears before the official mk2.5 update was available. And today again (latest mk2.5s firmware of course).
No skipped steps, normal mode, 220°C, PLA. I am currently at 99mm, which is good enough for me but I just tried different values without quite a system.
Board is a Rambo 1.3a. Anyone knows which is the default value for a MK2.5s ?