Problems with filament jambs

[printbus]

CalifDan, can you add a picture showing how the filament spool is oriented? I'm starting to see some torsion action on the end of my first roll of filament, and I think it has to do with my orientation of the natural curl of the filament on the spool with respect to the hobbed bolt.

[Roxy]

CalifDan, can you add a picture showing how the filament spool is oriented? I'm starting to see some torsion action on the end of my first roll of filament, and I think it has to do with my orientation of the natural curl of the filament on the spool with respect to the hobbed bolt.

This is very common. At least for those of us using really cheap filament! What I've started doing is winding the filament from one spool (the one it came on) to an empty used up spool. If you do this with 10' or 15' feet between the spools, you can watch for extra twists showing up and manually untwist the filament before it ends up on the new spool. This is annoying, and a nuisance, but it does really help with this problem.

[CalifDan]

CalifDan, can you add a picture showing how the filament spool is oriented? I'm starting to see some torsion action on the end of my first roll of filament, and I think it has to do with my orientation of the natural curl of the filament on the spool with respect to the hobbed bolt.

I can't do a picture for a few days. On a trip. However, I use the supplied roll mount from Makerfarm installed per instructions. I might have to make some different plans. A lot of good advice here.

[printbus]

...I use the supplied roll mount from Makerfarm installed per instructions. ...

Interesting. I was about to try reverting back to the MakerFarm mount. I recently switched to top side spool mounts with a rod between them that runs parallel to the LCD. I now see that definitely leads to an un-natural feel of the filament going into the extruder and past the hobbed bolt - the filament just wants to turn sideways from how it is being fed in order to return to the direction of the curl on the spool. My issues were with a MakerFarm spool of PLA. I've added spool hubs with bearings to fit the mount rod. What happened in my case is I stopped to check a print, and as I watched the spool started unrolling and a large loop of filament came off the spool. There was apparently enough torsion in the filament to overcome the bearing resistance, leading to filament being "pulled" from the side of the spool as a way to reduce the torsion. While still printing, I was able to remove the spool from the mount and remove the twist, but if I had left this go I could see ending up with tangles like you did.

After the print was done, I retracted and re-fed the filament, marking it with just a small dot a ways from the extruder. Running a test of 100 or 150mm extrusion, I could see the dot starting to rotate. At least in my case, I think that's the cause of the torsion in the filament, since the newly fed filament didn't have any torsion in it when I fed it.

Roxy's advice on rerolling spools is noted. I don't have an empty spool to try that on. Until I have one I'm going to experiment with different spool orientations and maybe filament guides. I'm thinking the top-side mount I have now is the worst possible orientation, at least with free-spinning bearings in the spool hubs.

[Roxy]

Roxy's advice on rerolling spools is noted. I don't have an empty spool to try that on. Until I have one I'm going to experiment with different spool orientations and maybe filament guides. I'm thinking the top-side mount I have now is the worst possible orientation, at least with free-spinning bearings in the spool hubs.

I didn't have an empty spool the first time I did this. What I did was hold the spool sideways and just let the remaining filament unspool and get pulled to the floor. And then I put it on a broom handle sitting on two chairs and wound it back up.

But here is something else to check for. I'm guessing a little bit but I think it explains things: I think some of these filament sellers buy big long monster rolls of filament. And they start with an empty spool and just start winding it onto the new, little spool and let it pull off 1 circle of filament at a time without letting the big roll of filament turn. If that is really being done, what you will see is one complete twist of the filament for each big spool length of the filament. I've had some rolls like that. If that is the case, as you are rewinding the filament, you end up having to do a pretty constant rotation of your spool. I've had it where every 4' of filament, I had to twist the new spool 1 turn.

This is a real nuisance, but if your filament is twisted on the spool that you are pulling it off of, it is going to cause all kinds of bad behavior.

Oh! And one more thing I tried... You can't do this all the time, but if you uncoil the whole spool of filament and then go up to a walkway that looks down on the lower floor, you can sometimes start winding the filament onto the new spool and it will just untwist as you pull it up and wind it on the new spool. Somehow, as you start putting it on the new spool, the twist gets stronger and stronger until it starts making the pile of filament on the lower floor start rotating. It will naturally untwist the right amount as you put it back on the spool. (Make sure your floor is clean with no dust... Or you will be feeding that into your nozzle)

[clough42]

I wouldn't expect twist to be a problem if you're unreeling the filament. If you're allowing it to pull off the side of the spool (not unrolling) you'll have a hellacious twist problem eventually. I mount my spool on a pegboard behind the printer and let it spool straight down into the printer. I uploaded my spool holder to Thingiverse: http://www.thingiverse.com/thing:343197

This was before I figured out the retract speed issues with the MakerFarm 66 oz.in. motors, so you can see the wonderful blobs in the print.

[RobH2]

I'll second that with 'clough42.' I spool off of a turning spool that has a dowel in the center and have never had any twisting issues. Coming off of the side could certainly wind it up.

[Roxy]

I'll second that with 'clough42.' I spool off of a turning spool that has a dowel in the center and have never had any twisting issues. Coming off of the side could certainly wind it up.

I can assure you.... I have had a number of spools recently that have twists that get more and more pronounced as the roll turns on the dowel above the extruder. I understand why you are skeptical. But it is very real.

[printbus]

I'm not getting the "coming off the side" comments. For one I'm not sure what post is being referenced. What Roxy was referring to was filament repackagers that do this from a huge spool to the small spools we use. This is beyond our control and WOULD put a twist into the filament as it is wound on the small spools. What I was referring to in one of my posts is someway somehow the filament had enough torsion in it (why is moot for this point) that the pool started unrolling all by itself, and I observed a turn of filament eventually coming off the side of the spool (it isn't normally fed that way). (If your spool spins freely, manually start rotating the free end of the filament and you'll duplicate this.) The OP is using the angled MakerFarm mount on the left side of the i3v frame. So, no one here is using a filament spool feed that intentionally feeds from the side.

Clough42, my spool is mounted in the same orientation as yours, just with a different mount. I was printing away just fine on print after print. I haven't spent time experimenting with other options, but that seems to no longer work as I approach the end of the MakerFarm PLA spool I've been using. The OP and I may very well have different issues going on. I'm going to try and stay out of the thread and let it focus on CalifDan's looping of the filament above the extruder. EDIT: And yeah, I know I can unroll a bunch of filament to check for any pretwist, but like the OP I'd rather not have to expect to do that all the time. Every day this new "hobby" is getting less and less interesting to me because of these sort of nuances.

[Roxy]

What I was referring to in one of my posts is someway somehow the filament had enough torsion in it (why is moot for this point) that the pool started unrolling all by itself, and I observed a turn of filament eventually coming off the side of the spool (it isn't normally fed that way). (If your spool spins freely, manually start rotating the free end of the filament and you'll duplicate this.)

I have had this happen due to the twist getting more and more pronounced. All of a sudden, the spool will just spin and let a loop out to relieve the tension. I have seen this happen! The good news is if you take the spool off of the dowel, you can untwist it some amount and the filament will go back onto it nicely.