Extruder Skipping And Jam
I just got my MK2 almost completely together missing the 5015 Print Fan.
Thought I could try a test print without it.
Got it calibrated and ran a few MK2 V2 Calibration gcode prints to adjust the Z level
Some came out ok (wrong z level) but then some started to not extrude.
At first couldn't figure out what was wrong because nothing was coming out.
Then my ears "engaged" and I heard the "clicking" of the extruder pulley and saw the filament was pulling than skipping and falling back.
Looks like the filament was eaten away to form a crescent shape around the pulley like a backwards "C"
I tried removing the filament with the unload process it wouldn't come out, so I used pliers, it also wouldn't come out and ended up breaking off
in the extruder.
Had to remove the extruder and try to get the piece left out and nothing would get it out, Ended up destroying the whole PTFE tube.
So im really not sure which came first the Jam or the filament extrusion...
Did the Jam cause the filament not to extrude or did the lack of extrusion cause the Jam 😕 ...
Im using PLA and maybe because I didn't have the Print fan, would the PLA melt at the wrong point?
Im not sure why it went wrong and any advice would help, I am getting a 5015 fan and some more PTFE tubing to get it all back together soon
Re: Extruder Skipping And Jam
the missing 5015 print fan shouldn't cause any clogging or jam inside your extruder.
💡
the most important fan at the extruder is the small 30x30mm fan that cools down the coldend. if this one fails, you get into serious problems with clogging and much more serious: a melting extruder body. if you've build the printer yourself (no kit), make sure that the small extruder fan is capable of shoveling at least 4 cubic feet of air per minute. if it is not strong enough, the filament already melts inside the heatbreak (not at the nozzle).
furthermore: make sure that everything is correctly aligned (ptfe tube, pulleye, hole for the filament, filament) and that the springs are mediocre tightened (not to tight, not to loose -> approx. 13mm spring length at the genuine kit).
now you stated that you've disassembled the whole extruder, so make sure that everything is completely tight after reassembling it !
you're only allowed to reassemble the whole extruder head (nozzle, heatbreak, heater-block) @ high temperatures ! have a look at this video, that shows how to do so. if you don't follow that, you'll end up in a leaking hotend, which is a really nasty thing.
some copper-paste at the threads of the nozzle and the heatbreak would be a good idea as well.
when you get your new ptfe tube for replacement, make sure that it has a little chamfer at it's end (a pencil sharpener is quite useful for that).
and by the way... for aligning the first layer, there is a better way than with the v2_calibration.gcode.
dem inscheniör is' nix zu schwör...
Re: Extruder Skipping And Jam
Yes 30x30mm fan came with the MK2 extruder kit. (so it should be sufficient)
Think everything was aligned,
The springs were a confusing step because what I read in the instructions (forget exactly where that was now, book or online) it said to tighten the springs down to about 10mm (from what I remember...)
For the springs I have (not from the MK1 or MK2 kit) 10mm or 13mm would seem to be much too tight.
I at first started with what I felt was a reasonable level of tension still had extrusion issues
thought that maybe it wasn't tight enough so tried more which didn't help
Re: Extruder Skipping And Jam
Got my extruder back together.
I use Load filament and it loads fine. But when trying to print and tries to make the small filament moves the extruder motor skips.
It seems to pull and retract fine in large revolutions... but skips on the smaller revolutions 😕
I have tried loosening and tightening the screws to various lengths and it does the same thing every time...
Re: Extruder Skipping And Jam
I probably should've mentioned my bearing and shaft setup
The only other difference with my build is I bought a 625 bearing from the https://www.thebigbearingstore.com/625-2rs-625-zz-radial-ball-bearing-5x16x5/
Also I didn't have a shaft, so I used a 3mm bolt with nuts on the end and shoved it into place (maybe I should have used a 5mm bolt but then ends wouldn't have fit).
The 3x(12 or something like that) bolt fits perfectly with a hex nut on one end and the round allen head on the other.
But maybe because the bearing is 5mm it doesn't sit flush on the axle...
Does anybody know where to buy the bearing shaft?
Re: Extruder Skipping And Jam
Just Saw on a youtube video that the Extruder Bearing Shaft is actually a 3D printed part.
But I can't find the STL for it anywhere...
I guess I will have to have it printed on 3D hubs or something...
Does anybody know where the STL is?
Re: Extruder Skipping And Jam
...Also I didn't have a shaft, so I used a 3mm bolt with nuts on the end and shoved it into place (maybe I should have used a 5mm bolt but then ends wouldn't have fit)....
hmmm... that might cause the descirbed problems.
💡 for my own i3 mk2 clone i just printed with the platec filament a small 5mm diameter ferrule with only 4 perimeters and a 3mm hole at the center and used a 3mm bolt to enforce and assemble it.
...Just Saw on a youtube video that the Extruder Bearing Shaft is actually a 3D printed part.
But I can't find the STL for it anywhere...
such a simple part is quite easy to design by yourself. just have a look at designsparks-mechanical 2.0 (freeware, just needs a registration).
➡ just for your convenience (2 versions: 1 solid, 1 with hole to enforce it with 3mm bolt):
make sure that you've got a good 1st layer setup, so that the small but tall print won't fail. maybe using a brim would be a good idea.
dem inscheniör is' nix zu schwör...
Re: Extruder Skipping And Jam
Yeah I figured it was a pretty simple part, Just have to make sure to design it right as i'm going to have find someone to print it for me on https://www.3dhubs.com/ and want to get it right the first time 😉