how to stop extruder extruding filament when preheating
 
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richard.c16
(@richard-c16)
Active Member
how to stop extruder extruding filament when preheating

Whenever my printer is preheating it slowly starts extruding and when its doing its mesh bed leveling its making a stringy mess because its slowly extruding is there anyway to stop this ?

Posted : 18/10/2018 10:52 pm
alexander.s27
(@alexander-s27)
Estimable Member
Re: how to stop extruder extruding filament when preheating

That ist oozing and not active extrusion. Nothing you could do about, just wiping the nose at the right time..

Posted : 18/10/2018 11:52 pm
bobstro
(@bobstro)
Illustrious Member
Re: how to stop extruder extruding filament when preheating

You can tweak your startup gcode to avoid heating up to final printing temps until after mesh bed leveling is complete. The basic process is:

1. Pre-heat nozzle to a temp that won't cause oozing (e.g. 140C).
2. Heat the bed to 1st layer temp.
3. Do mesh bed leveling.
4. Heat nozzle to final printing temp.
5. Proceed with print.

I've done this (and a bunch of other stuff) in my g-code that you can view here. I've been able to eliminate the little dots and strings created during leveling by doing this.

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 : 19/10/2018 12:18 am
richard.c16
(@richard-c16)
Active Member
Topic starter answered:
Re: how to stop extruder extruding filament when preheating

I editied my gcode by putting mesh leveling before the preheat of the nozzle in slic3r and when it did the mesh leveling it failed the nozzle pushed down super hard on my bed causing the z axis to be uneven and almost damage my bed

Posted : 19/10/2018 7:51 pm
bobstro
(@bobstro)
Illustrious Member
Re: how to stop extruder extruding filament when preheating


I editied my gcode by putting mesh leveling before the preheat of the nozzle in slic3r and when it did the mesh leveling it failed the nozzle pushed down super hard on my bed causing the z axis to be uneven and almost damage my bed

Did you include the instruction to home the extruder position with G28 W before doing the mesh bed leveling with G80? You need to do that before the mesh bed leveling so it knows where it is in 3D space. Also, have you set your Live-Z properly?

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 : 19/10/2018 7:59 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: how to stop extruder extruding filament when preheating


I editied my gcode by putting mesh leveling before the preheat of the nozzle in slic3r and when it did the mesh leveling it failed the nozzle pushed down super hard on my bed causing the z axis to be uneven and almost damage my bed

No, you can't do that. You need at least 140 degrees on the extruder first, better 170 degrees.

Any blob on the nozzle will then be soft enough to allow calibration.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 19/10/2018 8:32 pm
richard.c16
(@richard-c16)
Active Member
Topic starter answered:
Re: how to stop extruder extruding filament when preheating

Did you include the instruction to home the extruder position with G28 W before doing the mesh bed leveling with G80? You need to do that before the mesh bed leveling so it knows where it is in 3D space. Also, have you set your Live-Z properly?

No i didnt do the G28 W ill try that.
And as far as the live-Z i set that with the first layer calibration and has worked fine in other prints. I just changed the G code to try and stop the extruding while doing the mesh leveling. thanks for the reply guys

Posted : 19/10/2018 9:32 pm
richard.c16
(@richard-c16)
Active Member
Topic starter answered:
Re: how to stop extruder extruding filament when preheating



I editied my gcode by putting mesh leveling before the preheat of the nozzle in slic3r and when it did the mesh leveling it failed the nozzle pushed down super hard on my bed causing the z axis to be uneven and almost damage my bed

No, you can't do that. You need at least 140 degrees on the extruder first, better 170 degrees.

Any blob on the nozzle will then be soft enough to allow calibration.

Peter

I made sure there was no blobs on the nozzle before print

Posted : 19/10/2018 9:34 pm
richard.c16
(@richard-c16)
Active Member
Topic starter answered:
Re: how to stop extruder extruding filament when preheating

Im doing a super detailed print atm and i notice that its making little stringy bits as it prints so i think there may be a flow issue how could i fix this ? I changed the settings on my slic3r and slowed the print to 40mms to try and get more detail im not sure if that would do this or if my print nozzle is too hot or is my flow set too high

Posted : 19/10/2018 10:25 pm
bobstro
(@bobstro)
Illustrious Member
Re: how to stop extruder extruding filament when preheating


Im doing a super detailed print atm and i notice that its making little stringy bits as it prints so i think there may be a flow issue how could i fix this ? I changed the settings on my slic3r and slowed the print to 40mms to try and get more detail im not sure if that would do this or if my print nozzle is too hot or is my flow set too high
You really need to share your slicer and settings with us. Over-extrusion might be the issue. Excessively high temps might contribute. Insufficient retraction might contribute.

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 : 19/10/2018 11:04 pm
richard.c16
(@richard-c16)
Active Member
Topic starter answered:
Re: how to stop extruder extruding filament when preheating

my print finished and it actually was alot better than i thought i think the stringyness was from printing such a small model with lots of supports but post clean up turned out quite well

Posted : 20/10/2018 12:37 am
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