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!
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.
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
RE: Extruder clicking and PLA filament jammed
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.
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
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.
PETG gets moisture contaminated?
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.
RE: Extruder clicking and PLA filament jammed
I don't want you to be right! I have too much filament I have only printed a few meters off of!!!
A week of fighting this issue. I rebuilt my extruder at 3am last night and thought I had solved it. My heat break wasn't flush with the heater block and the nozzle was just about flush. No leaks, but there was a ting PLA/PETG gasket in the block. I cleaned it all out, installed a brand new nozzle and calibrated. My layer 1 is not as good as the last nozzle, which looked almost ironed, but I have good adhesion. So I started my 6hour project, a 2 part model that takes up most of the bed.
The first printed perfect, layer 1 was passable until it started on part #2. It made an outline and then just started to spit filament onto the bed like a pissed off 5yo missing teeth. And that horrid non-retractions!!!
I went through 9 spools before I managed to find a non-opened one (that's a lot of filament). It's running now, just starting into the second part. [Sorry.. if you didn't know, this post is LIVE]... Pins and needles... [minutes and millimeters ticking by]... I have a 1st layer!
I'm thrilled and very sad. Is there any way to salvage all this plastic?
RE: Extruder clicking and PLA filament jammed
I don't want you to be right! I have too much filament I have only printed a few meters off of!!! ... Is there any way to salvage all this plastic?
If you read all the pages of this thread, you'll see solutions; for example see my posts above this one.
Basically you have two options:
- Bake your filament at low temperature (105°-120°F or 40°-50°C) for about 3 hours, preferably in a convection oven to distribute the heat evenly, and put a metal baking sheet under the filament to shield the spools from direct exposure to the heating elements (especially if it's a gas oven). The downside to this is that the filament anneals to the shape of the spool. Instead of wanting to be straighter, it wants to stay curled. This is a problem if you leave your filament in the printer for a day; the constant force of being straighter in a feed tube causes it to fatigue and break after a day.
- Get an airtight drybox or ziplog bag (you can by vaccuum filament storage bags on Amazon), and seal up your filament spools with a LOT of indicator dessicant, and leave it for a month. The disadvantage to this is that it takes time. If your indicator turns a different color after a month, recharge and replace it and give it another few weeks. If your container is well-sealed, the indicator shouldn't change color for dry filament after a few weeks.
I keep my filament in bags and rewinder dryboxes, all of which aren't totally airtight, so I'm changing the dessicant everywhere about once a month.
Some really hygroscopic materials (nylon and TPU) may be hard to dry out. I'd say PETG is the easiest; it absorbes almost no moisture to begin with.