I am currently building a Rostock Max printer. I am a Rambo v1.1 board, Repetier and slic3r. I was able to get some test prints yesterday but developed an issue with my extruder by the end of the day. It was pointed out to me that my extruder steps/mm were set up incorrectly (nearly 5x what it should have been)... which may have lead to the issues I'm having now?

The extruder motor seems to stutter when told to extrude.

Here is a link to a
video via dropbox showing the issue. I drew a black line on the pulley to show the lack of motion. Also pay attention to what the filament (dark blue) is doing.

Any insight into what is causing this or how to resolve it is much appreciated. Thanks!

Motor is skipping. Reasons can range from faulty driver, stuck/jammed filament, faulty wiring/connections, not enough current, invalid speed/accel settings, etc. If you didn't touch anything, verify that the filament is ok in the gear teeth area.

Is your extruder set to relative or absolute?

MPower Wrote:
-------------------------------------------------------
> Motor is skipping. Reasons can range from faulty
> driver, stuck/jammed filament, faulty
> wiring/connections, not enough current, invalid
> speed/accel settings, etc. If you didn't touch
> anything, verify that the filament is ok in the
> gear teeth area.

It does the same thing whether or not there is filament in the theeth area, so we can cross that off the list. I had completed a calibration print ~30 minutes before this began happening (it was working fine for that print). I'm not sure if that helps
narrow the issue down. What's the next logical thing to check?

>Is your extruder set to relative or absolute?

Where do I check this setting? In the firmware or repetier settings?

Well.. remove the filament and see if the gear is turning correctly with no filament engaged. That will rule out if the filament is preventing the gear to turn. If it still doesn't turn, you have a wire connection or driver issue, the erratic "half-way movement" looks like one coil of the stepper motor is powered only.

By the way, did this happen after you tweaked something or out of the blue?

Edited 1 time(s). Last edit at 08/04/2013 06:06PM by MPower.

To find out if your extruder is set to relative or absolute (or any axis for that matter), you open up Marlin.pde in arduino and go over to the "Configuration_adv.h" file in the tabs. It should look something like this (you will need to scroll down a little bit):

#define AXIS_RELATIVE_MODES {false, false, false, true}

The true statement is where I have my extruder set as relative.

As you are using slic3r, check your "Printer Settings" tab and see if "Use relative E distances" box is checked or unchecked.

Edited 2 time(s). Last edit at 08/04/2013 07:05PM by kburr.

kburr, you saved my day and my parents' Repraps life! Thanks for mentioning relative/absolute coordinates for extruder.

After playing around with random settings in pronterface, this output made me suspicious:

SENDING:M92 E10
Extruding 1.000000mm of filament.
echo: too long extrusion prevented

Edited 1 time(s). Last edit at 08/23/2013 02:20PM by tobben.

hi tobben,

could you please explain what followed, i am having the same issue as you, any advise.

mello'

I had a stuttering E-motor, sometimes stuttering slowly forwards, sometimes backwards. I had the source code for the Marlin firmware available on my computer, so I opened the file "Configuration_adv.h" and found the line

#define AXIS_RELATIVE_MODES {false, false, false, false}

I changed that to

#define AXIS_RELATIVE_MODES {false, false, false, true}

and uploaded the modified firmware to my microcontroller. The stuttering were gone, both when controlling manually via Pronterface and when driven by Slic3r's gcode.

Hope this helps Let me know if you need further details.

Sounds like i am having the same issue as you. I am using Repetier firmware. Anyone have a solution for this.