Purging AOK but no extrusion for first layer calibration
 
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MCMuckle
(@mcmuckle)
Active Member
Purging AOK but no extrusion for first layer calibration

Hi,

As the title suggests, I have no problem with a good solid purge but as soon as I go to first layer calibration nothing (or very little) comes out.  I am confused because both processes use same hardware (nozzle (not clogged), extruder (no clicking)).

When conducting first layer calibration the initial extruded line to clear the nozzle (that lays a line on the near side of the heatbed) extrudes well.  It is only the actual series of calibration lines that fail.

As far as I can see the only other thing is software.  Somehow the command to purge works but the command to first layer calibrate does not.

Any thoughts?

Thanks

This topic was modified 10 months ago by MCMuckle
Posted : 05/01/2021 12:53 pm
bobstro
(@bobstro)
Illustrious Member
RE: Purging AOK but no extrusion for first layer calibration

The purge line is printed before mesh bed leveling, so is not subject to the results. Verify that the filament is actually not just extruding but not adhering. I'd start with recalibrating your Live-Z.

If you're using custom start gcode, make sure there's no extra retraction without detraction after the prime line prints.

Consider printing a skirt around the print as this will use the ABL results.

 

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 : 05/01/2021 2:58 pm
MCMuckle
(@mcmuckle)
Active Member
Topic starter answered:
RE: Purging AOK but no extrusion for first layer calibration

Hi,

Thanks for the reply.  As I find it, the purge line is done after the levelling procedure, immediately before the calibration lines.  TBF the purge I described as working fine was the Filament -> Purge command, which works well.

No, as I see it, the purge line in first layer calibration works well but no filament is coming out to make the lines.  I have raised the nozzle during this process to have a better look but no, or very little filament emerges.

I think I will just go straight for a print with a reasonable skirt and do live height calibration to hopefully get it working nicely before the print proper.  Not a solution but a work-around at least...

Posted : 05/01/2021 5:07 pm
bobstro
(@bobstro)
Illustrious Member
RE: Purging AOK but no extrusion for first layer calibration
Posted by: @mcmuckle

[...]  As I find it, the purge line is done after the levelling procedure, immediately before the calibration lines.  TBF the purge I described as working fine was the Filament -> Purge command, which works well.

Doh! Yes, the purge line is after MBL. What I meant to say is that it is not generated by the slicer, so uses raw gcode. That might be a hint for narrowing down where your problem lies.

No, as I see it, the purge line in first layer calibration works well but no filament is coming out to make the lines.  I have raised the nozzle during this process to have a better look but no, or very little filament emerges.

The purge line will use the layer height specified in the startup gcode. The skirt and actual print will use the settings in the slicer settings. It's odd that no filament is extruding at the start. If you're using custom start gcode, you might want to verify no odd retractions are done after the prime line prints.

 

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 : 05/01/2021 5:19 pm
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