Correct method to unload filament
 
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Shree Kumar
(@shree-kumar)
Trusted Member
Correct method to unload filament

I spent a few hours prior to this clearing the heat break - filament was stuck there. I read a good bit about how filament gets stuck in the heat break. You know the "don't retract PLA more than 2 mm" stuff. (Slic3r default settings seem to be 2 mm for retraction)

I have been trying to figure out what caused the filament to get stuck in the heat break. According to the E3D wiki, they are using about 0.8 mm of retraction with PLA, but they recommend between 0.5 mm to 2mm. So the default Slic3r value is at the higher range, but may still be OK.

I have been basically printing two color models with ColorPrint. The models are themselves quite small (6cm x 2 cm x 4mm). This means that I keep changing filament often.

I use 210 degrees with PLA (default config). I generally unload the filament using the unload option from the UI, or due to M600 (filament change). While the unload is in progress, I gently pull at the filament, helping it along.

I have a suspicion that the way I am unloading the filament could cause the filament to get stuck in the heat break. Is this possible ? Is there such a thing as the right method to unload a filament ?

Thanks
-- Shree

Opublikowany : 23/06/2016 8:23 pm
Josef Průša
(@josef-prusa)
Member Admin
Re: Correct method to unload filament

Hi shree,

are you using our settings? We have 0.8mm retraction set in Slic3r profiles.

Founder and owner / Majitel a zakladatel
Opublikowany : 23/06/2016 8:27 pm
Shree Kumar
(@shree-kumar)
Trusted Member
Topic starter answered:
Re: Correct method to unload filament

Hi Josef,

are you using our settings? We have 0.8mm retraction set in Slic3r profiles.

Yes, I am using "Prusa3D Slic3r MK2" installed the official "drivers" package on Windows. Print settings for "0.20 mm NORMAL", "Prusa PLA 1.75mm", and Printer set to "default".

Horror of horrors for me right now -- Printer"default" seems to be settings the nozzle diameter to "0.5" and retraction to "2 mm". Printers "Original Prusa i3 MK2 with ZHop" and "Original Prusa i3 MK2 with ColorPrint" are configured like you say.

What's the "default" setting for ? I've been using the "default" printer all the while without actually noticing the 0.5 mm nozzle dia.

Thanks
-- Shree

Opublikowany : 23/06/2016 8:40 pm
David T.
(@david-t)
Noble Member
Re: Correct method to unload filament

What's the "default" setting for ?
Default setting is set of configuration parameters consisting of values compiled directly into software. It's usually unusable. 😉

Opublikowany : 23/06/2016 9:01 pm
Shree Kumar
(@shree-kumar)
Trusted Member
Topic starter answered:
Re: Correct method to unload filament

Totally ! Just set my printer to "Original Prusa i3 MK2 with ColorPrint" and it is actually printing much more nicely.

With the earlier setting, the printer seemed unaware of the filament color change. This would result in a line across the model in the new color in my case. With ColorPrint, it tries to resume printing while minimizing the movement. Nice results !

Good lesson learnt for today...

Opublikowany : 23/06/2016 9:11 pm
Harrison Spain
(@harrison-spain)
Active Member
Re: Correct method to unload filament

I had my first major clog on the factory assembled Prusa this weekend. I had to remove the fans, and release the extruder idler bearing, and heat up the extruder to 240, and I got lucky with a hard pull.

But enough of my woes... what's with the firmware "Unload filament" option? First of all, it should not even attempt to unload unless the extruder is above 150 right? Why compain that you have to pre-heat the extruder? Why not just heat the extruder, and THEN eject the filament?

Next... why do you have to "Unload filament" over and over and over to get the filament to actually eject? This should be a one step operation right?

---

On my Mini, I just heat the extruder, squeeze the extruder stepper pinch thing, and give it a tug. Comes out every time. I then manually feed in the new filament. Done.

On the Prusa, I expected to either duplicate that procedure (I can't seem to free the extruder by pinching the two screw thing) or use the firmware option which does not appear to work.

What am I missing?

Harrison Spain
[email protected]

Opublikowany : 12/06/2017 3:35 am
Harrison Spain
(@harrison-spain)
Active Member
Re: Correct method to unload filament

In addition, "Load filament" spits out a ton of filament all over my part... not ideal.

Harrison Spain
[email protected]

Opublikowany : 12/06/2017 3:37 am
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