Notifications
Clear all

Extruder clicking and PLA filament jammed  

Page 4 / 4
  RSS
Anachronist
(@anachronist)
Estimable Member
RE: Extruder clicking and PLA filament jammed

Unfortunately re-applying thermal paste didn't fix the problem. I even completely replaced the heat break and nozzle with brand new ones, a heat break specifically for the MK3S+MMU2 and a genuine e3d nozzle. It jammed a bit over an hour into a 4-hour print.

The filament isn't getting stuck somewhere in the path from the spool through the MMU2S to the extruder. It's getting stuck in the hotend. It prints great for a while, and then experiences blockage that the extruder cannot overcome. It starts clicking and stripping the filament. If I pause the print, loosen the idler tension screw, and force the filament down into the extruder by hand, it's very difficult to force through, but then a glob of plastic comes out of the nozzle and everything moves smoothly.

This really seemed indicative of a thermal problem, as if the heat break was overheating. But that's unlikely now that I've replaced the heat break and applied fresh thermal paste (which I got from Prusa).

I'm at my wit's end. This printer was working perfectly in casual usage for a year (there are 24 days of usage in the printer's log), and now it's jamming all the time.

Any ideas? I've tried everything Prusa support suggested:

  • Checking the grub screws on the bondtech gear
  • Checking that the E motor shaft isn't bent.
  • Cold pulls
  • Dry filament (I store it in dryboxes with indicator dessicant)
  • Removing the hotend to examine the PTFE tube in the heat sink (the PTFE tube is in perfect condition)
  • Re-applying thermal paste (I also replaced the heat break and nozzle)
  • Ensuring uniform 0.5mm gap between nozzle and heat block

What else can I try? Besides pausing the print every 30 minutes, letting it cool, and then resuming, I don't know what else, and I'd rather not have to sit by the printer all day if I have a 14-hour print job!

This post was modified 9 months ago 2 times by Anachronist
Posted : 04/03/2021 11:13 pm
Anachronist
(@anachronist)
Estimable Member
RE: Extruder clicking and PLA filament jammed

SOLVED!

It turned out there was nothing wrong with my printer. I likely didn't have to replace the heatbreak and nozzle. The slicer settings (retractions, temperature) were just fine.

The problem was the filament.

All of my filament is over a year old. I store the spools in ziplock bags or dryboxes with indicator dessicant, and I refresh the dessicant. With that kind of care, why should I suspect the filament? The PLA isn't brittle, it's just as flexible as always. But something has clearly happened to it.

Trying a new spool of blue Prusament PLA, the print made it all the way through without any problems whatsoever!

The old white silk PLA jams after a few layers. My bronze silk PLA jams after 30 minutes; it's in better shape.

Doing a cold pull with the white filament, it exhibits a squishy, springy resistance as I push it through the extruder until the clog comes out. And it looks like it swells a bit after emerging from the nozzle. The new filament doesn't do that. It suggests that the filament is moisture contaminated, in spite of the care with which I store it.

So, instead of discarding half-spools of filament that gave me good prints the first six months I used them, I'm trying to restore them by baking the spools in the oven. My kitchen oven has a "warm" setting, in which a meat thermometer shows a range of about 105°F to 120°F (40°C to 50°C), which is about right for baking PLA.

Posted : 10/03/2021 2:05 am
JoanTabb
(@joantabb)
Moderator
RE: Extruder clicking and PLA filament jammed

@anachronist

Is your oven a Gas oven, or an electric oven? 

Gas ovens, usually have Hot Spots... that can melt your filament

If you have a gas oven, consider using a metal tray to deflect the harsh temperatures from the flames

 

regards Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 10/03/2021 2:39 am
Anachronist
(@anachronist)
Estimable Member
RE: Extruder clicking and PLA filament jammed
Posted by: @joantabb

Is your oven a Gas oven, or an electric oven? 

It's an electric convection oven, so with the fan on, the air mixes up inside and the temperature is pretty constant throughout the volume. I'm sure my meat thermometer isn't accurate, but on the "warming" setting, the needle never exceeds 120°F (yes, cooking here in the US is still imperial units, when nearly everything else in my life except travel is metric). If I had a gas oven, I'd contrive to put a small fan in there with the filament.

Strangely, the white silk PLA didn't get brittle at all from baking it, but the bronze silk PLA now snaps pretty easily. The bends from my spool through the MMU2S to the printer aren't tight (I use rewinders not the buffer thing that came with the MMU2S) so it shouldn't break while printing. I now need to try it out.

Posted : 10/03/2021 2:58 am
TheMadJedi
(@themadjedi)
Eminent Member
RE: Extruder clicking and PLA filament jammed

@anachronist

Nice one man, Good News
I was thinking of maybe the thermostat or heater for the block was playing up causing odd temps with the filament

Posted : 10/03/2021 9:58 am
hobbid
(@hobbid)
New Member
Same here but with PETG.

Same here but with PETG. After i did not print anything for 2 Months started reusing the printer and got a lot of problems with clicking and jamming. I tried a lot to get it fixed. In the end it was as described here. I opened a new package Prusament PETG and the same gcode which failed the last 3 times with "old" open Prusament nwo printed perfectly without any Problem. 7h Print time.

Posted : 29/08/2021 2:16 pm
Anachronist
(@anachronist)
Estimable Member
PETG gets moisture contaminated?
Posted by: @hobbid

Same here but with PETG. After i did not print anything for 2 Months started reusing the printer and got a lot of problems with clicking and jamming. I tried a lot to get it fixed. In the end it was as described here. I opened a new package Prusament PETG and the same gcode which failed the last 3 times with "old" open Prusament nwo printed perfectly without any Problem. 7h Print time.

It never occurred to me that PETG could get contaminated by humidity. Did you try to dry it out in an oven like I did with my PLA?

On another note, I reached a milestone: After two years of owning my printer and accumulating eight 1-kg spools of filament, I finally used up one spool! It was the brittle bronze silk spool mentioned in my comment above. I was curious what would happen as it ran out while printing a part. As soon as the MMU2 sensed it wasn't there, the printer stopped and asked me to remove the 30 cm of filament in the feed tube and feed new filament into the MMU2, after which it purged the nozzle, asked if the new filament was coming out, and continued printing when I confirmed. So I have a 30 cm length of scrap filament, which I'll use for hinge pins. I'll think of something to do with the non-recyclable spool.

Posted : 19/10/2021 4:26 am
Page 4 / 4
Share: