Problems with filament jambs

I am having a multi day problem printing a part. At about the same place each time, the filament is jamming. I have included pictures of the part (partial completion) and the filament. It is clear to me that the filament is going into the extruder either too fast, or is heating up and bending.

I have disassembled the .4 hex head and cleaned. I have readjusted everything, multiple times. I have adjusted the stepper motor voltage and it is dead on recommendation.

This showed up as I got into the last 25% of Ultimachine black filament. The filament up to that point worked well.

I have slowed the feed rate as low as 93%. I am now at a standstill and am at a loss as to what to do from here. Any help is appreciated.

CalifDan



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The pictures are pretty blurry. Is the filament getting soft enough that it is folding above the extruder? Wow. You've got a cooling fan on the hex hot end, right? Do the problems occur while you're watching the printer or you just notice after a while that the printer has jammed? The latter might be letting heat pass up the hot end, but the cooling fan should prevent that.

This is intriguing since I just battled a roll of TonerPlastics black PLA that would stop feeding at random. The hobbed bolt was chewing into the filament, and all I'd have to do to start over is retract out the filament that was there, cut off the damaged part, and re-feed it. Took a while to figure out that the roll had small bumps in it, some of which would hang up on the top of the hex hot end. Back to Microcenter that roll went.

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Originally Posted by printbus

The pictures are pretty blurry. Is the filament getting soft enough that it is folding above the extruder? Wow. You've got a cooling fan on the hex hot end, right? Do the problems occur while you're watching the printer or you just notice after a while that the printer has jammed? The latter might be letting heat pass up the hot end, but the cooling fan should prevent that.

This is intriguing since I just battled a roll of TonerPlastics black PLA that would stop feeding at random. The hobbed bolt was chewing into the filament, and all I'd have to do to start over is retract out the filament that was there, cut off the damaged part, and re-feed it. Took a while to figure out that the roll had small bumps in it, some of which would hang up on the top of the hex hot end. Back to Microcenter that roll went.

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It happens regardless of whether I am watching or not. This roll of PLA worked up until a few days ago for the most part. Had a few problems. I am into the last 10% of the roll. The cooing fan is on and running. The filament is folding above the extruder. In fact, it is folding above the hole that feeds down to the extruder just below the feed wheel.

I think you are developing an enormous amount of twist within the filament. This most often occurs in the last 25% of a tightly wound roll.
The filament wants to return to the shape it is holding on the roll and is doing so just above the extruder where it is warm enough and therefore soft enough for the twist tension to win.

That's a really odd one. It looks like a Wade's Extruder so the filament is being pulled in and not being shoved in. I have two suggestions depending on what causing it.

1. If the filament is actually melting above that hole, then something is way too hot in your enclosure (if you have one). If you don't have an enclosure, then that makes matters worse or you are in HELL and HELL has email. I don't think that the air envelope around everything should be anywhere close to the temperature to soften PLA. If that's the culprit, open the front and or side and see if the softening stops.
2. If a twist like 3D OZ suggests is occurring, then pull a few meters off of a spool and just have it freely floating so its nice and free to be pulled in. If that stops it then maybe it was some sort of twist that was building up as the filament was being pulled off of the spool.

Other than that, evaluate it again and send some more photos. Try to get them sharper so we can actually see what's going on. I'm curious to hear what your final analysis and solution is.

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Originally Posted by RobH2

That's a really odd one. It looks like a Wade's Extruder so the filament is being pulled in and not being shoved in. I have two suggestions depending on what causing it.

1. If the filament is actually melting above that hole, then something is way too hot in your enclosure (if you have one). If you don't have an enclosure, then that makes matters worse or you are in HELL and HELL has email. I don't think that the air envelope around everything should be anywhere close to the temperature to soften PLA. If that's the culprit, open the front and or side and see if the softening stops.
2. If a twist like 3D OZ suggests is occurring, then pull a few meters off of a spool and just have it freely floating so its nice and free to be pulled in. If that stops it then maybe it was some sort of twist that was building up as the filament was being pulled off of the spool.

Other than that, evaluate it again and send some more photos. Try to get them sharper so we can actually see what's going on. I'm curious to hear what your final analysis and solution is.

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Rob,

I do not have an enclosure. I do have the fan and shroud on the hex .4 extruder. I think that 3d might be right on the twist issue, or, I am getting too much heat traveling up the filament.

Since I posted the issue I went to a new roll of PLA. I also reduced the temperature after the first layer from 220 to 200 even. I have been able to make three of the parts without any problem.

Once I am caught up (probably next week) I need to stick that old PLA back on and see if the temperature change made a difference or not. If not, then I will unroll some PLA and try again and see if it is the twist. I'm hoping that it is a temperature issue, as not using or stringing out the last 25% of each roll is a pain in the you know what.

Also, taking with Makerfarm support, recommendation to vegetable oil my extruder. Interesting, and I might give that a try as well. They also suggest that I can't use Slicr 1.1.6 but frankly, every successful print over the last two days has been using Slice 1.1.6. I am curious what the problem is with 1.1.6. From my perspective, it seems to do a better job at filling the odd little spaces that show up.

I will post more after I test the several theories.

CalifDan

Ok, good feedback. I guess it's more likely to be a twist. If heat was getting that far up I think you'd be just "jammed" all the time. I'm wondering if it's not just a bad roll of filament. It happens.

So veg oil eh? Do you put it in the hole (filament path) of the extruder? Is that the idea, to lubricate the path? I may try that too. Interesting. Plus, as you print it will smell like french fries instead of plastic.

I have no problems with any version of Slic3r. I guess Colin has some issues with it and therefore does not recommend the newer versions. It really comes down to whatever works. I doubt that any version of a slicer is causing your problem. That sounds like it's mechanically based instead of code based.

I look forward to the new tests...

Waiting to hear the vegetable oil details too...

I've been using Slic3r 1.1.6 the last two weeks or so. I figured if I'm going to spend time optimizing something, I might as well do so on the newest version rather than be stuck in the past on an old version. Besides, support structures was revamped in 1.0.0, and that's really what I wanted to focus on. v1.1.6 definitely does better at filling holes and small gaps - almost annoyingly so. I've had one Thingiverse design I aborted the print on since the printer was spending about half the time going back and touching up where it must have thought there were holes or gaps. With identical parameters, top surfaces definitely turn out "fuller". But, gcode generation takes longer, and prints take longer.

I did notice that there are more parameters in the config.ini files with v1.1.6. Not knowing what difference that would make, I didn't even try to run with an ini file from 0.9.9. I just used the config wizard to start off new versions, and then used a text editor to compare the two ini files, migrating settings from the "old" file into the new file.

EDIT: Personally, I think the verdict on v0.9.9 and v1.1.6 is still out. I don't consider myself an expert, but printing 1-2 dozen things over the last couple of weeks leads me to think that the "best" version of slic3r to use may depend on the design. Everything I'm printing comes from Thingiverse. I've had designs not complete gcode generation in v1.1.6. Some prints in v1.1.6 seem to have real issues with nonsense head moves that do nothing, and other moves that seem inefficient. My bottom line observation has been that some items have done better printed from 0.9.9, others have done better in v1.1.6.

I use 3 in 1 machine oil (only about 2 to 3 drops or so) on my printed extruder gears only.

High heat in a pan on a cooking range is around 400 degrees F which is about 200 degrees C. I'm no Iron Chef but, I think vegtable oil contacting the hot end at some point might blacken the filament or emit smoke.

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Originally Posted by 3D OZ

I think you are developing an enormous amount of twist within the filament. This most often occurs in the last 25% of a tightly wound roll.
The filament wants to return to the shape it is holding on the roll and is doing so just above the extruder where it is warm enough and therefore soft enough for the twist tension to win.

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I agree that this is the likely culprit.

I have found that if I don't pull a good length of filament from the reel and let it dangle in space, the extruder stepper hasn't got enough oomph to pull the filament from the reel and so the hobbed bolt just chews away at the filament in the feed chute and there is no feed into the extruder. Now, this happened early on in the use of the reel, so I would think that as the end of the filament was being approached, there would be a number of physical problems with the feed.

I had my reel of filament hanging from the ceiling above my printer, so I could easily pull a few metres of filament of the reel and let it hang between the reel and printer. Since moving house, I have to set up a new printer area so I might have to investigate another solution to getting free-flowing unreeling of filament.

OME

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.

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Originally Posted by 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.

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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.

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Originally Posted by 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.

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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.

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Originally Posted by CalifDan

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

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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.

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Originally Posted by printbus

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.

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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)

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.

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.

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Originally Posted by 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.

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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.

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.

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Originally Posted by printbus

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.)

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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.

Very interesting. I've always had my spools unwind on a dowel (actually, a small section of PVC water pipe) and never ever had a twist issue. I'll keep an eye on it now that I know it can happen.

Here is what I did for a test. I took the roll of filament which was giving me the problem and unwound it out about 25 feet and turned the roll to takes the twists out of the filament (mostly). I then ran a 1.5 hour print and it ran with no filament feed issues (more on another issue in a moment). Based on that, and the fact that I have done about 20 hours of printing over the last five days on a different roll, I think the problem is the twist in the filament as I get towards the end of the roll. The problem filament is from Ultimachine (recommended by Makerfarm) and so is the newer roll I have used over the last four days.

If the same problem shows up in this second roll (might take a few more weeks to get down towards the end of the roll), then I am going to have to find a different filament vendor.

All of that said, the print was not problem free. About 3/4 of the way through, the whole print shifted about .1 inches on the y axis. I have never seen that happen before. I was using Cura. Also, Cura completely missed a rather large cut-out which starts at the first layer. I later bridged, but not without losing some of the part below where it finally bridged. I am not too worried about that, I can adjust the part to compensate for that, but the .1 shift on the y axis I do not understand. Bug in Cura? Or, did my Y axis suddenly shift by that much?

CalifDan

CalifDan,
Glad we could help with your twisted filament issue. I have encountered this issue with every roll I've used (dozens), some more than others. A good spool holder that feeds off close to the extruder drive helps a lot. Guides that keep the filament as straight as possible between spool and extruder help too. Not always practical.
I don't think it's caused by twists built into the filament during manufacture or large spool-small spool transfer. I think it is an inherent behaviour of the filament having been wound tightly around the relatively small diameter of the spool hub. This is why a new spool with the first 70% wound around the larger diameter of the remaining filament doesn't display this problem.

As to problem No2, do you check your Cura slices by changing to the "Layers" view before saving the G-Code? (Top right corner of the object view) I have discovered many Cura oddities before printing by performing this step. You would have spotted the missing cutout and could have corrected it. Check the expert settings and experiment with the "Fix Horrible" settings as these often cause strange results in Cura G-Codes. Use the layer view to check what Cura will do before you export your g-code or print.

Problem No3, the Y-Axis shift is hard to diagnose without more info. Does it happen often? Loose belts? Has it happened only once? Ignore and carry on.

3dOz,

The shift only happened once. Last print job. The belts don't seem loose enough to have slipped. In fact, I checked that first. I did not check the slices in Cura. I will repeat it and see what that looks like. I appreciate the advice.

I would like to figure out how to effectively use Cura. It seems to me that it is a lot more efficient than Slicr. However, I do prefer the support material that Slicr produces more than Cura. When I create a slot (rounded edge rectangle for example) Cura puts in so much material that I find it hard to remove without marking the part.

CalifDan

I'm no expert in CURA or Slic3r and I tend to use both. You will probably find one better than the other depending on the model being sliced.
CURA seems a little more intelligent regarding the order that it prints different elements but Slic3r is far more configurable (at least for me).
I'm no fan of the way either one of them adds in support material and I tend to model my own support into the object I'm printing.
This obviously takes time but gives you some more control over where and how the support is used.

Have you played with Meshmixer? It's pretty easy to get started with it (however it took me 20-minutes to figure out how to delete a model in the panel) and I liked the ability to add my own supports. You have to get used to them but the control is pretty amazing. I happen to like both Cura and Slic3r but I too find their supports hard to remove. That's why I started playing with Meshmixer last week. I have had some interesting results. It might be worth a try.

I started with MeshMixer. Maybe I will go back and give it a try. Modeling in the support seems like a good idea. That might take some experimenting.

CalifDan

It definitely takes some experimenting. Sometimes they come in at extreme angles that you know won't print or stand up. But there are controls to modify that. It allows you to add bracing between supports which was interesting. I got lost in just building crazy stuff and forgot all about a real print. I just had fun making a crazy support scaffolding for awhile. It was kind of fun. Who new you could have fun making supports?

But seriously, experiment with it. I was able to print a few things with minimal supports in comparison to Cura's supports "everywhere."

What version of Slic3r are the support comments pertinent to? The Slic3r release notes mention how support functionality was rewritten from scratch in v1.0.0.

Interesting. I did a print this morning using Slicr 1.1.7 and it completely missed the support for a long opening. It was a rectangle with rounded ends about .3 inches high and 2 inches long. Slicr put in the support at each rounded edge but completely missed the rest. It managed to bridge after a few passes on top, but unfortunately, an otherwise great print is not usable.

I loaded 1.1.7 yesterday. Otherwise, I have been going back and forth with Slicr 1.1.6 and the last .9 whatever version. I sure will be happy when they get 1.2 working where you can review the entire print. I tried 1.2 but it failed with a bunch of errors trying to output the g-code file.

CalifDan

Edit: Never mind, I had the don't support bridges box checked. Something new learned. I don't even remember seeing that before.

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Originally Posted by CalifDan

but the .1 shift on the y axis I do not understand.

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As others have pointed out, this is difficult to diagnose. It's possible that it's s software problem, but that's not where I would start. It's usually skipped steps on the motor or a skipping belt.

If you can precisely measure the amount of the shift with calipers, see if it's a multiple of *exactly* 2mm. If so, it may be a belt skip. If it's not exactly a multiple of 2mm, it's not the belt. Friction or inertia (or an outside force) probably overcame the motor's holding torque and it skipped some steps. By "outside force" I mean things like bumping the printer or getting your finger caught between the bed and the Y idler while trying to feel the belt tension. Not that I would know anything about that.

If it only happened once, ignore it. If it keeps happening, you can try making sure your mechanics are moving freely and try slowing down.

I printed the same part again, twice. I also printed some other parts and no recurrence. The shift was an even .1 inches. Just that once....and I did not have my finger in it. That is my story and I'm sticking to it.

CalifDan

I am resurrecting this thread. My respite from the filament jambs was short lived. I made some adjustments, but I think that I now know what the problem is.

Let's start by saying that I am changing from 1.75mm filament to 3mm. This was suggested by Colin as likely to be more reliable. I realized in ordering the necessary parts that it only requires a change of the hot end and new filament. I figured that the feed bolt and even the whole extruder mount might need to change, but not so.

Which means that the 1.75 filament is traveling between the bolt and the hot end entrance in a space designed for much larger filament. This is a space which allows flexing of the filament and that is exactly where my jambs occur. I think that the feed bolt, pushing on the filament against the back pressure of the hot end finally allows enough bend to cause the filament to kink. There may be some heat associated help with a longer print (where I usually get the jamb). That said, it makes sense that the thinner filament would need more, not less, support as it travels between the feed bolt and the extruder.

It the 3mm provides me a significant improvement in reliability, I am going to look into a modification of the extruder printed section to accommodate 1.75mm filament and test same. That might take awhile, but I will report back.

Any thoughts appreciated.

This just isn't making sense. Going back through the thread, you have a hex hot end with fan and shroud. The fan is wired to constant 12V so that it is on all the time, and not wired to the RAMPS D9 fan output, right? Is the fan one that MakerFarm provided? Does it seem to move air pretty good and make at least some noise (ie, does it work)? When you're printing, how warm does the aluminum plate under the extruder feel? Does the hobbed bolt chew into the filament when it stops extruding?

Just how "soft" is the filament cold? Does it bend a lot easier than the other PLA you have? We never did understand how you were getting those knots or folds in the filament above the extruder. Seems to me the filament is unusually flexible or you have some significant temperature issues going on.

Printbus,

The fan is wired correctly and runs constant. I do not notice any temperature issues up high, but frankly, the 1.75 is off the machine now and I can't test it. I used 1.75 filament from Makerfarm and Ultimachine. There were three rolls involved and all jammed.

I have installed the 3.0 filament hex head with .4 orifice. No jamming problems, however I am getting some pretty awful looking prints. Photo attached.

Attachment 2444

I thought that this photo might show the crappy perimeters from over-extrusion, but it appears that may not be the case. I set up a hollow cube to print for testing and I varied the feed rate and temperature until I got something that looked much better.

I came up with a feed rate at about 118% and a temperature of 198. This is for PLA. This is significantly off Colin's proposed settings. In fact, I forwarded the g-code to him and using an identical setup, his print looks fine. He wanted me to season the hot end with Canola oil. I did and that really made no difference until I varied the feed rate and temperature. I just want to get reliable and reasonably good prints.

I have another part printing right now. I changed the extruder multiplier to 1.18 and the temp to 198. We shall see how it turns out. Meanwhile, I am curious if extrusion multipliers should be that extreme?

OK, I need to edit this. It turns out that I loaded Slicer with a .5 mm head rather than a .4. I am not sure where in my tests that occurred. Anyway, now trying a print at 1.05 multiplier and lowered temps to 186. I was getting too much stringing at 196. Also, trying a Cura slice as Slicer (even though I selected avoid perimeters) was depositing a problematic amount of ooze in one particular spot.

I also seem to be unable to get retract to work in Slicer or Cura. I am not sure what I am missing as I had it working when I was using 1.75 filament.

What retract rate and length are you using?

4mm retract, 10mm sec rate

That sounds good. I haven't had much trouble with stringing with similar settings. I wonder how much difference there is from one brand and color of PLA to another.