Filament is very thin
I've been printing the same design on my I3 MK3 now for about 6 months using PLA. This was a pre assembled printer and I have the latest firmware up to today. I've put in about 300 hours printing this same design using the same brand of filament with no issues. I went to start printing today and the print starts fine for about 5 seconds, and then the filament is hair thin. I watched the extruder motor and I can see it visibly slowing down after the 5 seconds. I took it apart and there was nothing built up on the gears and I could freely spin them with no problem. I adjusted the tension screws on the extruder with no change in results. Whenever I start a print no matter what print it is, I get the same results: The print makes a nice .4mm line for about 5 seconds and then I have super thin lines. I've included a picture the Batman print that comes with the printer. You can see the test line on the bottom is a nice thick .4mm line, however the lines are so thin after that the print is ruined almost immediately (about 5 seconds later).
I've checked and cleaned the nozzle, I've adjusted the z-axis. I've run all the factory/self tests and everything checks out. I did a load filament and can visibly see it printing a nice thick line and then the extruder motor slows down during the load filament process, you can see the line width change to the small hair sized lines (picture included).
It could be the stepper motor for the extruder is bad? Like I said, this is the same design I've printed about 300 times with the same filament brand/color and this current spool has no issues as it is about a week old and worked fine up until today.
thank you
Re: Filament is very thin
Try Settings > Move Axis > Extruder to manually advance the filament for 10 seconds. Does the motor slow down while making a pile of string on the bed? If it reliably extrudes at the same rate for the 10 seconds, the problem is most likely not the extruder.
It is possible debris is stuck in the cold end of the extruder - at the teflon/heat break joint - and that jams after a few seconds. I used canned air to blow out the teflon tube to cure a similar problem. The filament debris and dust that came out was surprising.
Re: Filament is very thin
Thank you Tim,
I will try to clean the PTFE tube. I watched a video on replacing the PTFE tube.
In order to blow out the tube, what did you need to disassemble? Did you need to take it all apart and extract the tube or can you do it by removing fewer pieces?
Re: Filament is very thin
I did a cold pull then blasted ... I use "Dust Off" canned air with the long tube attached; I spent several seconds blasting the gears, the top of the teflon tube, the upper feed hole, and the filament sensor area. No actual disassembly was needed.
PLA:
1) Set Nozzle temp to 240c - wait for it reach temp and to smoke a bit
-- good time to wipe nozzle with paper towel to clean off any old plastic residue - it's hot, watch your fingers - and avoid the wires
2) Manually extrude 25 to 50mm of filament
-- don't move the extrude axis in the minus/negative direction, only go positive
-- if nothing is coming out, use the 0.3mm needle and poke it into the nozzle a few times to stir up any gunk, then try to extrude again
3) Set Nozzle temp to 90c
-- let the nozzle cool below 125c before next step
4) Loosen the two tension screws and open the idler bay
5) When nozzle temp is 95c or less firmly pull up on the filament and remove it from the extruder
-- it may take a bit of effort, but not much, some recommend pliers, but I've never needed them
-- if you're lifting the printer, something else is wrong 😯 🙂
6) Then liberally blast gear area with canned air ...
7) Close the idler door and gently tighten tension screws until you feel them engage the tension springs. Tighten the screws 1 more turn.
-- on my printer, screw tips protrude from the door about 1/16th inch, 1.5mm.
8) Load filament
Official COLD PULL instructions here:
https://help.prusa3d.com/l/en/article/WWVRzOY1dX-clogged-nozzle
Re: Filament is very thin
This indeed sounds like a clogged nozzle, but I can tell you I have never had to disassemble anything.
Just do a cold pull.
If you have ABS use that.
Remove the PLA
open the bontech gear screws
Preheat the nozzle to 220 or 230 for ABS
insert ABS filament by hand and push down until you get an extrusion
Switch off the heating of the nozzle
Keep a very light pressure on the filament, just to keep the nozzle full in case of oozing.
Let nozzle cool to 50 or 60C
Prepare pliers
Switch on nozzle heating (set temp of 130 should be enough)
While the nozzle is heating, grab the filament and pull firmly and straight up.
When the nozzle is just warm enough the filament will be released and you should see an imprint of the nozzle geometry at the tip.
Repeat if necessary.
This removes dirt from the nozzle.
Re: Filament is very thin
hi,
Thanks for the suggestions. I did a cold pull about 4 times. Each time it came out clean with the end looking a little bit clubbed like it was in the nozzle. I also blew compressed air as suggested.
Still getting the same thin lines of filament. Should I check out the PTFE tube? It seems clean based on the cold pull I did.
Re: Filament is very thin
How was the manual feeding of the filament? Did it extrude evenly with little resistance?
Can you go back to filament that used to work and print some first layer, and then repeat with the one you are having issues with? Post photos?
Re: Filament is very thin
As for cold pull, the filament that comes out should look like a nosecone of a rocket: Think Gemini capsule. And in many cases you'll also get a 0.4mm whisker from the orifice - which signifies a perfect cold pull.
But even after these, I was getting jams higher up the heat break. Something had fallen into the teflon tube and only came out with a shot of Dust Off. The amount that came out was rather spectacular, too. I had been using Glow - which is brittle and when the nozzle jammed the gears chewed material into thousands of minute chunks that went everywhere.
RE: Filament is very thin
I am having this same issue and can not figure out what the problem is. All was well then this came out of no where.
RE: Filament is very thin
What was the resolution for this @neil.g4? I have the same issue. Was fine, then changed filament and started a new print and exactly this issue. I also noticed my Z-axis was way out. Have carried out cold pulls, checked the nozzle, changed filaments, changed model printed, and can't get to the bottom of it.