WHAT CAUSES THIS!!??

[jereywolf]

I keep having prints fail because the filament just stops coming out. I have checked the filament diameter it is usually Ø.065"/Ø.070". I have tried less tension and more tension. It's happening to me with a fresh roll of ABS, as well as other rolls. I run ABS at 245°C. I have tried multiple g-codes. I even took my barrel and nozzle apart the other day and soaked it in acetone overnight (which didn't seem to do much, maybe I did something wrong).

After every time this happens, I have to retract and start over. The picture shows how the filament looks after I retract it and cut it off. It has a groove worn into it from the drive gear. Does that always happen?

I have mostly been printing Taulman Bridge and ABS over the last month.

Any help is very appreciated!

[Levi8than]

Work the problem. First check that the filament isn't getting good caught up in the tube somewhere. check to make sure the drive gear is spinning. Check if the teeth are worn out. See if your filament is being gouged by the teeth. Then proceed downward. Make sure your groove mount is tight and the filament isn't getting good pinched. Check for loose wires. Without the filament path can you manually push through a heated up hot end?

I don't have a lot more to suggest. You just need to debug to the.

[jereywolf]

Thanks! I took the drive housing off, and the gear was all gummed up with filament that it stripped out. So every time that it happened, it was probably more likely to happen the next time. I'll see how this works!

[Levi8than]

Great! The picture didn't load earlier. Now it's clear. Too much tension or over retraction causes this for me.

Happy printing.

[jereywolf]

I just had it fail again. I'm going to try backing the tension off all the way, then just barely putting it on until the bearing starts to turn as it's extruding.

[Levi8than]

Odd with abs. I've seen this with place after abs would the nozzle was clogged. Never happens to me with pla. Can you watch the temp as it is running? See if it droops or rings.

[davidb]

It might also be worth checking the z offset. I've managed to strip filament like that by having the bed too close to the nozzle for the first layer. When the filament doesn't have anywhere to go, something has to give.

[Levi8than]

I've got a new cause for you, and completely my fault. Check that your fans are properly running.
I just swapped my .35mm nozzle out for a .25mm nozzle and took it for a spin on a small detail part.
The first print went well; textbook. But the second started clicking and stripped just like yours. My mistake was that I swapped the fan connectors, and the smaller fan, the one that keeps the filament drive gear from heating up, was not running. But even after connecting fan properly and re-feeding the filament, it isn't working correctly. Still clicking. I'm wondering if I've got goop up in the groove mount, and its catching.

Oh well, I'll take it apart once it cools and figure it out.

[Capt. John]

Partially clogged nozzle is the place I'd look at first. Then, double, triple check nozzle space to build table clearance.
Carefully setting head space when the table is at operating temp will allow for heat expansion issues.

I have 3 glass build plates that are all slightly different thicknesses. Seems my top gantry (frame) has a .001
bow in it too. We're dealing with extremely tight .005-.006 head space to table clearance. A thousandth here and a
thousandth there ...will mess things up in a hurry!

Drive gear is another issue where I think we would all greatly benefit from a concave gear that grips
the filament on a 1/2 round, instead of just relying on the flat of the filament.

Moisture in the filament is not your friend. Seen steam shoot from mine when I cleared a
clog. Junky off brand filament has caused me loads of grief. Especially, when trying to print in glow.

Soon I'll be ordering .40 and .50 nozzles and see if this allows for the challenges in printing glow.

[jereywolf]

Thanks guys!

It's not an issue with the Z height because the problem, doesn't usually occur on the first layer. My fans are also working well, I have been using this 40mm fan for a while, it's great. So quiet. http://www.amazon.com/40x10mm-Bearing-P ... 0mm+noctua

Levi8than, I have only ever had the "clicking" from the drive gear not being able to turn. Which happens after filament gets wrapped around it somehow. The temps seem stable. I ran a successful 3 hour print last night (fingers crossed for my currently running print).

Capt. John, how do you clear a "clog" I have never done it before...Doe's switching between different types of filament really leave a "coating" on the inside of the barrel that just keeps getting thicker?

The Idea of a concave, drive gear sounds promising. Have you already tried to find one that is the right size?