Cleaning a M3 SE Hotend - Best method?

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polygonprint
Posts: 3
Joined: Thu Jul 26, 2018 2:38 am

Cleaning a M3 SE Hotend - Best method?

Post by polygonprint » Sun Aug 19, 2018 8:09 am

Hi All,

I have a M3 SE, one year old which has worked pretty well since purchase. Lately I have been having some issues with filament not coming through and the extruder motor 'clicking'. A cold pull procedure does not seem to be working, trying quite a few times without any luck - the extruder motor just clicks and jumps when retracting, eventually breaking off the filament at the top of the hotend entry point. I am after some advice on the best method for cleaning hotends and nozzles on the M3. I say M3 as I am not sure how the M2 hotend differs from the M3.

Cheers
Evan

Phil
Posts: 179
Joined: Mon Sep 19, 2016 7:49 pm

Re: Cleaning a M3 SE Hotend - Best method?

Post by Phil » Mon Aug 20, 2018 4:07 pm

First, have you removed the nozzle? That would be the most likely failure mode. I ensure mine are working by using a propane torch to consume any lingering plastic, then run piano wire through the hole a few times to knock loose any remaining ash. (This works especially well for brass. I would not do this on hardened steel nozzles, though.) I have occasionally found pieces of who-knows-what blocking the nozzle that are not melted or burned away.
The second most likely cause is a small piece of filament caught in the extruder housing. Remove it to check. You might also see filament in the gap between the extruder housing and the extruder itself.
If you have removed the nozzle and the extruder housing, you can heat the extruder, then hand-force some filament through it. Be careful when you withdraw the filament to first pinch off the blob coming out of the bottom. If you cannot force filament through, check its temperature.

For preventing jams with extremely soft filament, I have occasionally threaded it through the extruder housing before reattaching to the machine.

airscapes
Posts: 188
Joined: Wed Jan 31, 2018 11:36 pm

Re: Cleaning a M3 SE Hotend - Best method?

Post by airscapes » Mon Aug 20, 2018 4:50 pm

Once you get thing cleared it may be helpful to purchase some eSun cleaning filament. I use this any time I change filament types or if I notice inconsistent extrusion from the roll I am using. Truth be told once a week doesn't hurt.
This stuff has a very wide temp range so you can flush PETG at 255 and then use PLA at 210 with no issue.
The on caveat is that it is very inconstant in diameter and very soft. The trick to using it successfully is to set your extruder feed speed (manual feed) very slow as in 100mmMINUTE (1.6mmS) Then only feed 2 mm at a time and assist by pushing on the filament as you extrude. I run about 20mm of cleaner, then 100+ mm of filament to flush out the cleaner. If you don't get all the cleaner out, your first print will not stick to the bed. I pause about 1/2 way thought the 100mm to let the new filament melt/mix with any cleaner ..seems to work well.
I have not had a clogged nozzle since I started doing this.
Good luck!

polygonprint
Posts: 3
Joined: Thu Jul 26, 2018 2:38 am

Re: Cleaning a M3 SE Hotend - Best method?

Post by polygonprint » Tue Aug 21, 2018 12:42 pm

Thanks very much to the both of you. I have removed the brass nozzle. I mostly print with ABS so soaked it in acetone over night. I didnt have a fine enough tool to push through the nozzle but cleaned it as best i could. I am now back up and printing with that nozzle and hotend, but still cant perform a cold pull. I was hoping this would clean out any remaining crap.I plan to get some of the eSun cleaning filament. Thanks once again.

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