This is puzzling behavior I haven’t seen before. I’m stumped. It’s a printrbot simple upgraded to XL.
It has started doing this after a couple weeks sitting idle. It does it with various pla’s. I’ve had to reduce speed to 30% about 15mm/sec.
It starts out printing ok and gradually about the same height the extrusion starts looking like bead-chain, eventually blobs and hairs then stops extruding (jammed). It’s easy to clear, just pull back.
I thought maybe it’s just a couple degrees too cool but not so. Have run up to 219c and still problems. I tried upping flow along the way and sometimes can get thru a print that way.
I disassembled the hot end and cleaned. There might have been a tiny strand of the Teflon tape loose but even after cleanup blob and hair.
Any ideas are welcome! Meanwhile I ordered a new Ubis cartridge hot end from printrbot.
What are the teeth on your extruder like? It looks to me like there is possibly some sort of skipping or slippage. Maybe it might even be the pla, what sort of storage have you been using for it?
tried three PLA’s One brand new out of vacuum seal container from Hatchbox, others from Deltamaker stoled with slica gel. Plus humidity in NW Montana is desert like.
Teeth are clean on the extruder.
I monitor the temp while it’s printing - it’s extremely steady the whole time.
One thing that changes is the fan come on after 3 layers at 75% (stalls at 50 and sound like hell below 75)
Of course all this USED TO WORK. Wondering if there is a microscopic flaw in the nozzle the is building up a mess.
hate to break it to you, but that’s what you always get when the extruder is clogged, the nozzle to be exact. take it off, put it in acetone, shake it. put it back on, manually push filament through it with a temp 12-15 degrees above normal printing temp. you’ll have it resist a bit then it’ll unclog. when that happens just reset the printer so the temp goes down “faster” than going through the printer’s menu. it happened to me 4 times with a 0.4 mm nozzle. and I print with PLA mostly. I hope you give it a try and I’d love to hear back with an update
@Adrian_Ciubotariu Acetone does not dissolve PLA. The proper procedure for clearing a clog is a “cold pull” - http://bukobot.com/nozzle-cleaning - I agree that this is a nozzle clog, however. The cold pull procedure works well with PLA @ 100C - and worst case scenario, you can take a single bristle from a wire brush, and shove it up through the nozzle while at temp, and then cold pull it (to ensure the obstruction is caught in the plastic material when it’s pulled out)
Before you take the extruder apart, bring the extruder to the height or slightly above where things start to go wonky. Bring up to temp and then extrude without filament. If there is skipping & stalling without filament you may have a wiring issue. If it works fine without filament then try with filament and look/listen for skipping/stalling.
@ThantiK I’m not gonna tell you I know it doesn’t disolve PLA, but you probably do know that acetone will remove any, and I do mean any, burnt materials, cleaning the metal. shaking the nozzle will loosen any burnt particles - reason why i mentioned manually pushing filament afterwards, until the clog goes away. otherwise I would have said “shake it until it dissolves” but I didn’t, cause it’s not ABS. it’s tried and tested.
@Adrian_Ciubotariu it takes a bit longer than just a shake to get burnt PLA off of a metal nozzle. It’s just simply not worth all that disassembly, mess, and hassle in my opinion. Cold pulls are simple, clean, non-damaging, quick, and effective.
Excellent ideas. @Josh_Ajima that is head slap obvious but I’m too tired to think of it. Thanks. @Adrian_Ciubotariu@ThantiK I may try a dilute lye bath. Somewhere I have a recipe for dissolving PLA and I have an ultrasonic tank sitting idle. It’s warm enough I can do it outside (fumes).
WIll try these tonight.
Cold-pull all the way!.. I use regular .065" trimmer line to clean my hotends. It usually takes 3-6 pulls to get things back to normal, which is a lot easier than taking everything apart and using heat or chemicals.
Thanks all - time for a trip to Lowes. Trimmer line (as I have no nylon or ABS on hand) and Lye to dissolve the foriegn bodies - the burnt PLA - wait this is going to get me flagged somewhere.
Occam’s razor makes me ask: did you change your extruder steps recently? (It looks like under-extrusion). If so, then your E-steps are off. If not, then yeah, clogged nozzle, yadda, yadda see above.
I had that behavior when my hot end was clogged, not the tip. If you feel like experimenting you could try some of the eSun cleaning filament. I’ve always been curious about its effectiveness so if you do try let us know how it works out…
Works pretty well after doing a cold pull with a more rigid material like pla/abs itself or the nylon that others suggest.
I had a bit of underextrusion happening and the cleaning filament helped clear that up. Best to do a cold pull of the original
Material, run some cleaning filament, cool down, and cold pull that. It softens up at a lower temp than pla which is what I believe helps get the gunk out.
best of luck!