Jump to content
Ultimaker Community of 3D Printing Experts

UM2+ cannot print Marlin/Reprap (SOLVED)


Recommended Posts

Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

I need to print a temperature tower with an Ultimaker 2+ Ext, which is impossible with 'ultigcode'. In order to change the temperature multiple times at custom layers, marlin or reprap are required, both of which are being completely rejected by the printer. Sometimes (but not always) the hotend fails to heat up, usually the first layer starts a full extra layer above the (levelled) bed, and it always fails to extrude anything. None of these behaviours occur with ultigcode. Something is massively wrong with how the UM2+ is reading (or refusing to) anything other than ultigcode.

I have compiled the marlin/reprap files under several different versions of cura, dozens of different print profiles, attempted printing via usb and sd card, nothing at all works.

  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    It is or should be easy, just go to the printer setup in Cura, change gcode flavor to Marlin and that's it.

    I use Marlin on my UM2+ and UM2Go without any problems. In fact ultigcode and marlin is nearly the same, the only difference is that with Marlin you can choose the material and temp in Cura.

  • Link to post
    Share on other sites
    Posted (edited) · UM2+ cannot print Marlin/Reprap (SOLVED)

    In the gcode generated by cura, both marlin and reprap extrude only a tiny fraction of filament for each move compared to ultigcode. The difference is not constant (and yes I use identical material settings for both marlin and ultigcode)

     

    Below is a snippet of the ultigcode file which prints properly:

    Quote

    G1 F1200 X88.494 Y91.863 E0.05013
    G1 X88.938 Y91.573 E0.10025
    G1 X89.421 Y91.353 E0.1504
    G1 X89.932 Y91.208 E0.2006
    G1 X90.537 Y91.138 E0.25815
    G1 X90.957 Y91.128 E0.29785

     

    Below is a snippet of a marlin file with identical material settings, identical profile, identical model, identical printer.

    Quote

    G1 F1200 X88.494 Y91.863 E0.00786
    G1 X88.938 Y91.573 E0.01571
    G1 X89.421 Y91.353 E0.02358
    G1 X89.932 Y91.208 E0.03144
    G1 X90.537 Y91.138 E0.04047
    G1 X90.957 Y91.128 E0.04669

     

    This is only one of a list of problems that make marlin/reprap unusable on the UM2+. A single click on the "gcode flavour" dropdown in cura makes the entire file useless junk.

    Edited by user978537432
  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    Strange, it works well for me and all others, so it would be interesting what's different to your setup.

     

    I haven't changed anything except the gcode flavor dropdown. I printed long time with ultigcode, then changed the flavor to marlin, sliced the file and printed it with the same result. Now mainly via Octoprint, but it was the same with SD card.

     

    A difference could be that I use the Tinkergnome FW on my UM2 printers, but don't know if this makes a difference.

  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)
    4 hours ago, user978537432 said:

    In the gcode generated by cura, both marlin and reprap extrude only a tiny fraction of filament for each move compared to ultigcode.

     

    UltiGCode uses volumetric values for the extruder, all extrusion amounts are specified in mm³ (cubic millimetres).

    That's approx. a factor of 6,38 compared to the linear movement of 2.85mm filament.

    The values in your example show exactly this factor - so that should be fine.

     

    Just take sure that you don't set the extruder to volumetric mode (no M200 in the start script) and restart the printer between prints with different gcode flavors (just to be sure).

     

  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    In addition to what @tinkergnome says, the UM2+ detects what gcode flavor the file is sliced and uses either volumetric extrusion amounts (in the case of UltiGcode) or lengths (in the case of Marlin or Reprap).

  • Link to post
    Share on other sites
    Posted (edited) · UM2+ cannot print Marlin/Reprap (SOLVED)

    So I just installed a brand new linux mint OS on a completely different laptop, installed a brand new instance of the latest cura and, again, using completely identical settings for all 3, compiled to ultigcode, marlin and marlin (volumetric). I made no tweaks whatsoever, this is cura's own Ultimaker 2+ Ext default settings out-of-the-box. I allowed each to print 1 layer of an overhang test.

    The results are as follows:

     

    Utligcode (correct outcome):
    ultigcode.jpg

     

    Marlin (severe underextrusion):

    marlin.jpg

     

    Marlin volumetric (severe overextrusion):

    marlin-volumetric.jpg

     

    Note: marlin was printed FIRST, after a reset of the machine, so that appears to make no difference.

    Edited by user978537432
  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    The problem with the under extrusion is in your start gcode (or the default one)

    Filament is retracted too far away from the nozzle from your last print or after loading and the start code primes not enough. So the Print starts in fact without filament. You can modify your start gcode to prime more filament, then the print will be fine.

    • Thanks 1
    Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    These codes should work:

     

    Start GCode
    
    ;### UM2Ext Start GCode ###
    M42 S255		;turn led on
    G21 		;metric values
    G90 		;absolute positioning
    M82 		;set extruder to absolute mode
    M107 		;start with the fan off
    G28 Z0 		;move Z to bottom endstops
    G28 X0 Y0 		;move X/Y to endstops
    G1 X10 Y10 F4000	;move X/Y to front of printer
    G1 Z40.0 F9000 	;move platform up
    G92 E0 		;zero the extruded length
    G1 E20 F200 		;purge nozzle quickly
    G1 E30 F100 		;purge nozzle slower
    G1 E35 F30 		;purge nozzle slowly
    G92 E0 		;zero the extruded length again
    G1 F9000		;set speed
    M117 Printing...
    
    
    End GCode
    
    ;### UM2Ext End GCode ###
    M104 S0 		;extruder heater off
    M140 S0 		;heated bed heater off
    G91 		;relative positioning
    G1 E-1 F300 		;retract the filament a bit before lifting the nozzle to release some of the pressure
    G1 Z+1 E-19 X-20 Y-20 F9000	;move Z up a bit and retract filament even more
    G28 X0 Y0 		;move X/Y to endstops
    G28 Z0		;move Z to bottom endstops
    M84 		;steppers off
    G90 		;absolute positioning
    M107 		;turn fans off
    M42 S0 		;turn led off

     

    • Thanks 1
    Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)
    22 hours ago, Smithy said:

    The problem with the under extrusion is in your start gcode (or the default one)

    Filament is retracted too far away from the nozzle from your last print or after loading and the start code primes not enough. So the Print starts in fact without filament. You can modify your start gcode to prime more filament, then the print will be fine.

    Yes, that worked, thanks so much. I just doubled the default purge amount from 10mm to 20mm and added a retract to clip the prime blob and the first layer of Marlin now works great.

     

    For any googlers out there, here's what I did (changes from default settings in bold, edit the textbox in machine settings labelled "start g-code") :

    Quote

    G21 ;metric values
    G90 ;absolute positioning
    M82 ;set extruder to absolute mode
    M107 ;start with the fan off
    G28 Z0 ;move Z to bottom endstops
    G28 X0 Y0 ;move X/Y to endstops
    G1 X15 Y0 F4000 ;move X/Y to front of printer
    G1 Z15.0 F9000 ;move the platform to 15mm
    G92 E0 ;zero the extruded length
    G1 F200 E20 ;extrude 20 mm of feed stock
    G92 E0 ;zero the extruded length again
    G1 E-1 F500 ;retract to snip prime blob
    G1 Y50 F9000 ;fast wipe away from prime blob
    ;Put printing message on LCD screen
    M117 Printing...

     

    I'm sure I can figure out some tweaks to get marlin volumetric working too.

  • Link to post
    Share on other sites
    Posted · UM2+ cannot print Marlin/Reprap (SOLVED)

    I am glad that it works and thanks for the feedback. 

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    ×
    ×
    • Create New...