More fillament issues

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jeeplvr
Posts: 212
Joined: Sat Jun 08, 2013 5:26 am

More fillament issues

Post by jeeplvr » Tue Aug 27, 2013 12:47 am

Ok, I bought a spool of octave filament from a vendor and they sent me a spool of the sort that comes with the UP Mini. It is the only spool of filament that gives me issues. My extruder stops extruding it during prints and not during general extruding. I assume this is because the filament is being extruded slower during a print. All other issues with filament have been traced back to the binding of the spool rotation or a dirty extruder, clogged gear etc. So I started thinking about humidity and its affect on the ABS. Without searching the forum for an hour I am posing this question:
Do different makes of ABS react differently to humidity? The nominal diameter of the white filament is similar to the octave filaments but for unknown reasons it jams shortly after the print starts. It is jamming regularly and the humidity is way up today.
How do I tell the difference between pla and abs? If my spool is labeled wrong this might explain things.
Last edited by jeeplvr on Tue Aug 27, 2013 2:13 am, edited 1 time in total.

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JuliaDee
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Re: More fillament issues

Post by JuliaDee » Tue Aug 27, 2013 2:01 am

Well, if it's PLA that would definitely explain it. See how well it dissolves in acetone; I don't think PLA dissolves/softens readily in it like ABS does, but I'm not 100% sure.

Check the alignment of the feed gear with the filament path. Drew Petitclerc pointed this out a few months ago - some units don't have the feed gear pushed on the shaft far enough and so it's not centered on the filament. Just found this condition in my early-2012 Up today. Gave it a careful tap with a hammer via a piece of brass tubing, with the opposite shaft end supported with a metal pin and now it lines up perfectly.

Having the platform initial height sett too high can cause feed problems from back pressure in the first layer or two. Try dropping it 0.1 or 0.2mm and check that it's fairly constant over the whole bed (my Up's aluminum plate is slightly higher in the middle than at the edges even when it's "level", i.e. it's not flat. Not sure if it was always like that...

julia

jeeplvr
Posts: 212
Joined: Sat Jun 08, 2013 5:26 am

Re: More fillament issues

Post by jeeplvr » Tue Aug 27, 2013 2:11 am

I will check the feed gear alignment, thanks for that tip. I have some ABS that dissolves better in acetone than other ABS but I didn't know that pla is resistant to acetone, thanks again.
Sorry I keep calling it ply instead of pla.

jeeplvr
Posts: 212
Joined: Sat Jun 08, 2013 5:26 am

Re: More fillament issues

Post by jeeplvr » Tue Aug 27, 2013 3:10 am

just spent an hour measuring the filament in question and found that the areas where the filament seems to be jamming is indeed not jamming. The filament is only 1.68mm in some spots so the extruder gear is not grabbing the ABS solidly because the ABS is too small. My Octave measures 1.74 to 1.78mm. This is the only thing I can see that would explain why I could simply give the filament a little push and it would start extruding again and then stop after a few seconds.

doraemon
Posts: 94
Joined: Wed Sep 19, 2012 3:37 am

Re: More fillament issues

Post by doraemon » Tue Aug 27, 2013 4:39 am

PLA will not dissolve in acetone. I asked a chemist friend what we could use to dissolve/solvent weld PLA, as it didn't appear acetone or MEK would do the trick (though those work well for ABS). After trying all sorts of things only available in a full-blown chemical lab and not to your average layperson, he said something about using caustic soda with anhydrous isopropyl alcohol, then heating it to some high temperature, would dissolve PLA. Alas, when the solvent goes away the PLA does not re-form. I'm probably not quoting him exactly, but I'm no chemist. :mrgreen:

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