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Marius Strom
(@marius-strom)
Active Member
Filament jams

Howdy - My MK2s has nearly 7 days of print time on it (according to statistics) and it's been flawless pretty much.. Until yesterday.

I just started having issues of what appears to be filament jamming. What happens is during a print (I've seen it on 10um layer- and 20um layer-sliced STL files) the first few layers seem to go well, but after a time (not predictably) the extruder starts making a bit of a juddering sound. I put a dot on the extruder axle so I could watch it, and it seems to skip backwards about 30 degrees every time it makes the sound. When it does this, obviously very little filament comes out and the prints failed.

Tonight, I was able to catch one when it happened, and rapidly selected change filament from the menu. This bought me a little time to figure out what was going on. When the printer tried to eject the filament, it didn't spit it out. I had to tug on it with some good force to pop it out, and I notice the end where it enters the tube appears a little melted and enlarged (2.05mm, instead of the nominal 1.75mm that the rest of the spool is).

My guess is that the filament just above the hot end is hitting a temp high enough that it can go soft, and the printer smushes it, and once smushed, it can't make it into the hotend.

Any suggestions for what to do? This is 3DMakerWorld PLA in silver, and I was printing in an enclosure (that measured 39C) with a 205C hotend. Up until the failure point, the prints look great, no sign of overextrusion so I don't really want to pull back on extrusion multiplier. Until I figure out what's going on, I can't really run any long-duration prints since I need to babysit it.

Posted : 28/07/2017 8:48 am
LaPointe
(@lapointe)
French moderator and translator Moderator
Re: Filament jams

Printing PLA at high ambiant temperature can lead to filament jam. Try to print again with your enclosure open to check if this is the reason.

Posted : 28/07/2017 12:02 pm
Marius Strom
(@marius-strom)
Active Member
Topic starter answered:
Re: Filament jams


Printing PLA at high ambiant temperature can lead to filament jam. Try to print again with your enclosure open to check if this is the reason.

Thanks, I wondered about this as well and just started a new print with the enclosure open. I thought I had nicked the issue last night after resetting all of Simplify3D 4's settings, but the part failed again at the last 0.5cm of height. 😐

I had printed 30 hours worth of PLA prints since building the enclosure (Monoprice PLA) without any issues, so if this doesn't fix my issue, I'll switch filament types and see what happens.

Thanks for the suggestion. I'll update the thread no matter what happens.

Posted : 29/07/2017 6:20 am
JeffJordan
(@jeffjordan)
Member Moderator
Re: Filament jams

anyhow, if you put your printer in an enclosure, you have to consider an increase in problems with filament jam and/or clogging.

the design of the E3D v6 hotend requires a decent cooling of the aluminium heatsink above the heatbreak.
quote from the E3D website about this:
The heatsink must be cooled! Heated chambers, fan ducts that restrict flow, and not having the fan running at 100% at all times are common causes of issues. The heatsink should be cool to the touch at all times. If your heatsink is warm to the touch then you have a cooling issue that must be addressed.

and touching it all times, without burning your fingers, means below 50°C (about 40°C would be optimal).

dem inscheniör is' nix zu schwör...

Posted : 29/07/2017 9:32 am
3DBastler
(@3dbastler)
Eminent Member
Re: Filament jams

I had no problem with my closed box (Knickohr design), not with PLA nor with ABS and S3D up to now.

Your filament data says: extrusion temperature: 160 degC - 220 degC
So as first idea I would decrease the extruder temp for this filament in steps by 5°C to see what will happen.

Second, have a look to the retract settings. If you use 0.8 then ignore the following:
I increased it to reduced the stringing from 0.8 to 1,65. This was too much and forced jam during long time prints. I went back to 1.5 which worked for me with Prusa PLA, layer height 0.2.

Posted : 29/07/2017 11:38 am
raul.d
(@raul-d)
New Member
Re: Filament jams

I'm having the same issue without an enclosure. Is there any way to test my hot end fan to make sure it is working 100%? I've had case fans die on my computer before and they lost rpms before fully dying.

Posted : 03/08/2017 2:41 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Filament jams

is the fan blowing in, or sucking out?

it should be blowing in...

the fan supports should be on the inside

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 : 03/08/2017 10:01 am
AJS
 AJS
(@ajs)
Noble Member
Re: Filament jams


is the fan blowing in, or sucking out?

it should be blowing in...

the fan supports should be on the inside

regards Joan

Well, I'll be. I have had my fan running the wrong way all this time! (With no clogging issues, even in a modestly warm enclosure.)

http://manual.prusa3d.com/Guide/5.+Extruder+Assembly/295
Step 25, picture 2 clear shows you are correct!

I was planning on upgrading this fan this weekend anyway, but will fix while I am at it. Thanks Joan.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 04/08/2017 3:21 am
raul.d
(@raul-d)
New Member
Re: Filament jams

Confirmed, fan is blowing in.

aaron.s5: What are you upgrading the fan with/to?

Posted : 05/08/2017 12:52 am
AJS
 AJS
(@ajs)
Noble Member
Re: Filament jams


aaron.s5: What are you upgrading the fan with/to?

I will let you know if it turns out to be a good idea. I currently have my doubts. Hopefully this weekend.

This is a very active discussion here:

http://shop.prusa3d.com/forum/improvements-f14/alternative-nozzle-cooling-t4395.html

but I am trying something different - which might or might not pan out.

Edit: Above is the wrong thread. I meant:
http://shop.prusa3d.com/forum/improvements-f14/extruder-fan-specification--t1524.html#p19167

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 05/08/2017 2:00 am
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