Preventing and Fixing Jams - Tips & Tricks

[barry]

Tnx for the great tips Alex!

[Arnoldas]

That’s exactly what kind of guide I was looking for. Awesome!

[Bram]

Cool! How does an extruder look from the inside, like in a cross-section? Where can all this material get stuck?

[nick_theunisz]

Thanx for the tips

[AtomJaay]

This would make for a great slick infographic!

[gabriela3d]

That’s a brilliant idea, @AtomJaay, thanks! We’ll definitely take it into account

[MetaCAD]

this works fine for me or an acetone wash as above

[thormj]

My method of unclogging / cleaning between colors is to use nylon (http://bukobot.com/nozzle-cleaning):

1. Heat to 235, extrude 10 mm of nylon ('til the color change and you are dispensing nylon.

2. Reduce heat to 120, fan on, and keep forcing the nylon (slowly) in. It will stop when it gets < 200… don’t force it any more.

3. Wait 10 minutes to make sure the temp is down.

4. Break off the tip that has gone beyond the nozzle.

5. Release the hobbed bolt and pull the nylon back through. This will require force… if you get back a “little tip”, you got it all.

6. Snip the used end and Repeat until the Nylon comes out clean.

As far as oil goes, I’ve heard that it’s based on the same idea as “seasoning” cast iron… more updates in a couple of days. I didn’t need it with the “traditional” hot ends, but I have needed it for both name brand hot-metal units (E3Dv5 and Pico). Note that “ideal temp/speed” varies a *lot* based on the extruder (I think the thermistors just aren’t good enough).

[Jim_12]

I have my doubts about the nozzle size being 3mm. Maybe you wanted to write 0.3mm.

The only jams I have been having with my E3D is because of bad filament. Some bad pieces that do not want to melt, even at higher temperature add up after many hours and will eventually clog the nozzle. Even heating on a higher temp does not help anymore then.

Fortunately the acetone treatment works very good to clean the metal parts of the hotend.

This is a very good list. Nothing more too add!

[MetaCAD]

this looks good if you have time to strip the head

cheers

Barry

[thormj]

For good-quality extruders, it’s a straight bore of ~1.8mm diameter until the last 1mm where it necks down to the desired diameter.

For a cheap knockoff, they sometimes have wide spots in the middle (usually they use a brass insert to go “Bowden-less” – and that insert isn’t long enough to go all the way to the narrow channel)… which really sucks because you can’t use the Nylon method (nor anything else besides an acetone bath and cursing).

Problems that cause stuckage (from my experience):

1. If you have a PTFE tube (conventional hotend, or some metal ones with a PTFE insert except the E3Dv6), if you get it too hot, the PTFE tube melts and you gotta replace it.

2. If the “melt zone” is too large (all metal hotends primarily), the filament gets soft in the 1.8mm section and sticks to the walls, requiring too much force to get it pushed through). Use a fan. Use (a little!) oil (ABS and Nylon seem to do better). Some old E3Dv5’s had a brass nozzle that was incorrectly machined which exacerbated the problem (use lots of oil – 2 drops at start of every print).

3. When changing filaments going low (ie, going from ABS to PLA), you could have some ABS residue. If that makes it to the tip, it will jam because it won’t extrude at the low temp.

4. When changing filaments going high (going from PLA to ABS), you could have some PLA leftover. That can carbonize at high temps and cause a clogged tip.

5. If your thermistor falls out, the tip will get too hot and will carbonize anything in it (and probably set off a smoke detector!).

6. I imagine, if you’re commonly printing with filled filaments, you will start causing scratches on the plumbing. I’ve not noticed that yet (and I don’t run anything that exotic often)… disassemble and polish with a pipe cleaner and rouge (rinse when done!).

2-5 can be dealt with using Nylon-clearing if you have an all-metal-hotend (230 kills your PFTE tubes).

[thormj]

Oh… and for the “acetone wash” - to make it more effective (and freaking dangerous, so proceed with caution):

1. Mix 50-50 MEK-Substitute and Acetone (MEK substitute [NOT MEK] works better on PLA). [Not the dangerous part, but makes vapors more easily than pure acetone]

2. Heat the parts before you drop them in. Agitate afterwards. Danger! Do not light on fire or blow yourself up as these are explosive/flammable!

[Arnoldas]

I think Number 5 is exactly what happened to our Ultimaker right now! Right @Linda_Zouad ??

Thanks for the tips @thormj!

[gr5org]

Acetone doesn’t do anything for PLA - just ABS.

[gr5org]

You forgot about the “cold pull” method! That’s the easiest and best. There is a version below talking about doing a nylon-cold-pull but any filament will do.

Heat the filament a bit below printing temp (200C is fine for ABS or PLA) and shove some filament in there so there is good contact (this is in case there was a retraction). Then cool the head to the “cold pull” temperature (about 90C for PLA and 120C for ABS but temperatures can vary by 60C depending on nozzle design and filament diameter). Then pull real hard on the filament. It should take at least 1kg force - usually more like 5kg or 10 pounds. If it comes out too easily then lower the temp. If it doesn’t come out at all raise the temp until you learn proper cold pull temp for your nozzle and plastic.

It should come out in the exact shape as the inside of the nozzle. Complete with black specs of gunk and any cloggint things like sawdust or dust.

[Linda_Zouad]

Yes, it’s the part we ordered!

And awesome guide by the way

[MetaCAD]

I USE TAULMAN NYLON FOR THIS IT REALLY SOAKS UP THE CR@P

[StephenC]

e3d website state 245c is max for PTFE

[thormj]

I finally got tired of doing the cold pull manually, so I made some custom (read: short!) g-code for it.

http://www.thingiverse.com/thing:965194

I do that every 5 runs now just because it’s easy.

[Lauren_Pinshape]

Thanks for the awesome info! These are the top problems I’ve had: Heat creep, hot end temperature too low, nozzle too close to the bed, inconsistent filament diameter and dust/particles that get stuck.

When particles get stuck, I also use the cold pull method:

Step 1: Heat the nozzle to printing temperature and manually feed about 10cm of filament through the hot end (where the bowden tube was). Try and keep the filament as straight as possible. Natural or clear coloured filament works best so you can see the residue when you pull it out. If your hot end is too clogged to get anything out of the hot end, take a thin wire and a pair of plyers and stick it into the tip of the nozzle to clear the blockage.

Step 2: Once you have some filament coming out of the nozzle, bring the nozzle temperature down (120C for ABS, 90C for PLA, and 100-140 for Nylon). Try to use the lowest temperature possible for this step. It should be hot enough that the filament is malleable but not so hot that it is too soft. Be sure to cut any filament off that is dripping from the nozzle before you start the pull.

Step 3: Pull on the top of the filament until you feel it start to slowly give out. If it comes out too easily and there is no residue on the end, lower the temperature. If you have trouble pulling it out, raise the temperature until it does.

I give a more detailed break down of fixes to some of the other problems as well in my blog. Hope this is helpful!