extruder steps: measured calibration value gives terrible results...what's wrong?

Hello guys,

For some reason the calibration methods described everywhere seem not to work out for my printer & toolchain combination. I can't understand why. Here are 2 cube prints I stopped during infill printing to show what's happening:



The object to the right was printed with Esteps/mm=1134. This value was obtained by telling pronterface to extrude 100mm, measuring the actual length consumed on the input side and then readjusting Esteps/mm until exactly 100mm was consumed, just as prescribed by all callibration pages (triffid hunter's page, the reprapwiki,...) . So mechanically speaking, this value should be very close to the final result.

However, the left object is printed at only 370 Esteps/mm, which is the value I càlculated, also according to triffid hunter's page, using the formula on the wiki page.

We observe there is a huge difference between the mechically measured value and the theoretical one, and this result clearly shows in the printed objects. The left one seems a lot better, the nozzle did not dig into previous layers, layers aren't squished together, etc... Could anyone explain what's going on here? Should I look into the firmware, slicing settings,...I'm lost on how to proceed. Anyone who could solve this mystery would be my instant-hero

I have: classic Mendel with adrian's geared extruder, GEN6 electronics, Marlin software (25-02-2012), pronterface and slicer, a 0,5 nozzle and 3mm filament with layer height set at 0.2953 (best value according to joseph prusa's calculation page)

Have you checked your extrusion multiplier in the slicer? I'm asking this because if you have the right calibration but a big multiplier it will result in over extrusion , and you might be re-calibrating to compensate for that setting in your slicer.

Edited 1 time(s). Last edit at 11/16/2014 11:16AM by ggherbaz.

Hey ggherbaz,

I also get the feeling somethings "multiplying" somewhere :-) But it's not slicer, the multiplier is and always has been at 1...could firmware or pronterface do a multiplication somewhere? Or should we look elswhere for the solution...

That being said though...I did the manual 100mm extrusion using the pronterface GUI... so for calibration there was no slicing involved...I assume there is nog "extrusion multiplier" hiding behind those buttons??

Edited 2 time(s). Last edit at 11/16/2014 11:26AM by homecore.

The other thing might be "extrusion Width" for a 0.4 nozzle should be 0.48, for 0.5 should be 0.6.

I don't think there is anything else in the firmware beside the steps.

Have you checked this part of the settings? a multiplier might be hiding here?

Try following the procedure below to get "fine tuned

[wiki.solidoodle.com]

---

_______________________________________
Waitaki 3D Printer

The other thing that might be wrong in your slicing settings is the filament diameter. For example, if you are using 3mm filament but your slicer is set for 1.75mm filament, then the printer will over-extrude by a large factor, which seems to be happening when you use the 1134 value.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].