Extruding Problem
Need help figuring how to attack this problem...
First the lead up. During a print, the filament broke (I know why and fixed issue). But when the filament broke, the printer stayed at PLA printing temp of 205 degrees for about three hours with no filament being extruded. The next morning, I loaded filament and a small amount of very runny filament came out, then this was quickly followed by normal hot filament being extruded. I started a 24 hour print and about 5 hours in, filament jammed and quit extruding but printer continued as if everything was printing just fine. I found the problem about an hour later and stopped the print. This time it was about an hour of no filament being extruded, but there was filament properly loaded, it was just not being extruded.
I unloaded, loaded another color of filament, and printed another model that took about 1.5 hours. The print completed just fine and I installed the print (a filament guide). Now I loaded the gray filament to resume the failed print above. I preheat for PLA and the filament loaded just fine. Start the print... Nothing extrudes. Multiple load cycle attempts without removing filament, nothing extrudes. Now, unload, reload, nothing. Now unload, trim filament end to nice clean cut. Filament loads and extrudes just fine during loading cycle. Start print, nothing extrudes. Load cycle again, nothing. Unload, trim, load cycle, extrudes just fine. Start print, nothing extrudes. I unloaded, trimmed, reloaded three times. Each time filament comes out during the loading cycle. But, when I start the print, nothing.
Also, between loading and printing twice I kept the heat on with no cool-down between loading and printing (only a minute or two between loading and print start). Once I allowed the print head to cool to around 150 before starting the print (print head heats back up just fine). This made no difference.
Also, I tried two different brands of gray filament, both spools of which I have printed models before with no issues.
What on earth could be the problem??? The ONLY thing I can figure is a deformation of the PTFE tube? I noticed each time when I unloaded there was a bit of a bulge at the end of the filament. This is why I started trimming before reloading as mentioned above. But the PTFE jam seems like it would not be an issue if the print head temp stayed at 205 and never dropped between loading and printing.
Re: Extruding Problem
I am tempted to say: just take the hot end apart and see what you can see.
It kinda sounds like the standard nozzle / hotend cleaning won't do much good. If you want, try some cold pulls. Or the trick with heating the nozzle (no filament loaded) up to 250°C (since you printed PLA previously 250 sounds good), possibly with the fan disconnected - hoping that it might soften up some clog higher up in the usually colder zone. Poking from the bottom (guitar string, accupuncture needle) or a small allen key or somesuch (1,5mm perhaps?) from the top might do something.
Re: Extruding Problem
Well I found the problem and figured I would post for the benefit of others....
I performed a cold pull with nylon 3 times and the nylon came out clean and clear. So I checked the hobbed pulley on the extruder motor. It was gummed up with a lot of filament residue/dust. Not sure why it got so full off filament residue, but it was packed with a good bit. Cleaned it well and we are back to normal.
What I cannot figure out is why filament loading worked EVERY time, but extruding during print never worked. Does not make much sense to me, but okay. It is fixed. 😀 😀
Re: Extruding Problem
george
with loading the filament there is very little pressure so it will load ok
when it is extruding you need to force the filament against the 'plunger' or plug of softened filament acting as a piston to force the filament out of the nozzle.
so with the gear partially clogged the filament would be ok loading/inloading but as soon as it needs pressure for extrusion it will start slipping.
glad you got it sorted
phil
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