Help with Printer filament jamming up

[SummersideGuy]

I am just about ready to give up. I have a chinese brand Kossel Mini which I received a week ago and did all the assembly and bed leveling. For the first 3 days it printed great, I have attached couple of prints, then for the last 3 days nothing but a headach… the filament keeps getting stuck and the extruder bearing either ends up chewing it or not spinning at all. I am not getting consistent even feed rates either I will have layers with too little as compared to other so there will be delamination of the plastic. I did not have these problems the first 3 days of printing and everything was going great. I have attached photos of prints from the first few days I had the printer up, running, and well leveled.

Then about 3 days ago now it started feeding inconsistently and jamming and sticking. Now last night I took the whole hot end assembly apart and cleaned it all and put on a new nozzle and still the same thing keeps happening. I measured the filament in various sections and the diameter ranges from 1.5mm up to 196mm. It also is not perfect circumference for example if i measure a spot and get 1.54 then at the same spot measure the perpendicular i might get 1.74. I am not sure what it is. I don’t know if it is my extruder, my hot end/assembly, the filament. I have been testing with various temps. All my successful prints have been with 205-220 for temps. In one of my attached photos I circle the most common area for the pla jamming up.

I dont know if I should by another hot end assembly or if the filament is shit, am I using too high a temp for the pla, if so why so many decent prints at that temp and now this

[ProtoPrynt]

This sounds to me like a very poor quality filament… If it varies by almost 0.5mm I would demand a refund or throw it out/recycle it.

[tpalagyi]

Definitely looks like a filament issue, its way to off and not even round, 1.95mm will not be possible to pushed into the head so the extruder will grind it or loosing steps. Try to spool down 10-15 meters and measure again if still crap, try to return the filament to the supplier.

Tolerance should be 1.70-1.80 maximum for filaments.

Br.,

Tamas

[SummersideGuy]

measurements of my filament

[ProtoPrynt]

i would not even try to print with that much variance in diameter

[3DPrintandStuff]

In does sound like a variation in filament thickness as the reel get towards the middle.

Do you have some other filament that you could use, that’s measures up better? I wouldn’t say it’s a hardware fault, swap out the current filament for some better quality and if it starts printing like it did before, then it’s the filament at fault.

[SummersideGuy]

Ok so I have a 2 meter sample roll that came with the printer and tried it, made a 2 inch high 10% infill .2mm height raccoon statue

See where I highlighted in the photo showing a small amount of inconsistency with flow. I just finished this print, it used almost all the sample piece, I am not sure if this help determine anything as it only took 30 minutes for it to print.

[SummersideGuy]

Yes It printed fine for a few days until I got almost halfway into the reel. I only have a couple meters of blue sample that came with the printer kit. I will not order from this manufacture again, they are called MG Chemicals, I purchased on Amazon.ca.

[SammamishHub]

While the filament thickness issues are certainly a red flag, I’ll offer a couple more things to check, based on my having the same issues a while back. I mean, you got some successful prints, and then things went bad. Sounds very familiar… I think I’ve actually had all of these problems at the same time before:

1) Check gears on your extruder drive and make sure there is no loose play at all in their movement. If either of the plastic gears turn independently of the other, or of the motor spindle, that’s bad. Even just a mm’s worth. In my case, the plastic at the center of the large gear started wearing out so that it wasn’t locked onto the hex screw holding it in place. So as a print extrudes and retracts, back and forth, it eventually gets to a place where there are so many retractions in a short period of time, that the gears are turning back and forth without actually driving any filament forward. I super glued it together long enough to print a new gear and mount it better (with a bead of super glue from the get-go.)

2) Make sure the hobbed gear is clean – grinding on filament fills the grooves and the teeth don’t grab like they used to.

3) Too high of a retraction distance. I’ve seen advice particularly about keeping the value low for PLA (1.2mm or less, YMMV), as it’s kinda sticky, and if you get too many retractions in a row (most slicing apps have settings for mitigating that situation), it can pull it up into the cold part of your hot-end assembly, cooling the PLA and jamming it up above your hot end.

4) Cross-wound filament. I often re-wind a new spool of filament manually onto another spool, because there are often spots where it’s been wound so tight by the manufacturer that the extruder can’t pull off the spool. Then it just grinds away on that one spot. But that problem would likely have been obvious.

5) A crazy thing I would have never guessed to try – I tried this piece of advice and it seems to be working – reduce the current to your extruder motor when using PLA (and back up again for ABS.) Go into your firmware and find the setting:

#define DIGIPOT_MOTOR_CURRENT {135,135,135,135,135}

and adjust one or both of the last two 135’s (extruder 0 and extruder 1.) “135” represents a value from 0 to 255, where in my Marlin firmware 135 => ~0.75A. I use 85 to have it pull about 0.5A. This will allow the motor to slip a little if it has difficulty pushing filament through the nozzle for a moment, rather than viciously grinding away at it.

[SammamishHub]

Just saw this after posting my reply. I have the cross-wound filament issue consistently with MG Chemicals filament, especially about halfway through the spool. It may not get stuck for good, but can cause gaps like you’ve pictured while it struggles to loosen the knot. I like MakerGeeks’ filament, but I’ve had this problem even with theirs - halfway through the spool.

[SummersideGuy]

I actually recently tried increasing the current to the extruder motor as per someones suggestion as before it was just skipping and not doing anything when there was a jam up

For extruder it is a simple bowden with an MK8 and a large bearing, nothing else and I even put in a new mk8 bearing to see if it was the issue but it was not

[3DPrintandStuff]

I’m thinking by saying “cross-wound” that could also be known as “twisted”

I have seen the effect of twisted filament upon a print, it can actually be so twisted that it’s able to pull back upon the extruder causing it to skip and click. If you feel the filament you should be able feel the tension within. When it’s not twisted, it feels relaxed same sort of feeling when you first place in the extruder. Sometime you can rotate the reel 180 in opposite direction of the twist or another method is to unwind until you see the twist; then wind back on the reel keeping the twist off the reel.

I done it a few times to almost the end of a reel but was able to print with once the twist was removed.

[SummersideGuy]

I had reduced the retraction to 2mm originally it was max of 4 as this has a bowden tube. My filament keeps getting bound up/stuck in the hotend somewhere. ive disassembled the hot end several times and restarted but within 30 minutes or so it is slowly getting bound up again

[SammamishHub]

Yes, exactly - that’s just the name that came to mind as I picture them moving the filament back and forth as it’s wound onto the spool. I get filament trapped underneath the next loop, and I can just push it into the knot a bit to loosen up a few more windings, but it’ll eventually hit the next stuck spot.

[SummersideGuy]

I do find the filament strand itself is very twisted and feels knotty and very springy, see photo. Is it hard to straighten this out, could this solve some of the issue. I know I will never order this crap brand again.

[PepCo_Parker]

Hello! I too have a Chinese printer kit, well, actually three… and I must say in the beginning it was rough but man once these things get working are they ever a piece of art! I have to ask, are you printing with Chinese filament? Some filament is actually extremely poor in quality, not just the diameter or shape but the plastic itself. My first printer I bought came with really good filament, but the next two had filament that was better off being burned than trying to extrude it. I also have to ask, as I made this mistake myself, when you cleaned the extruder assembly, did you do so with a torch of some type? I was unaware at the time, but there’s actually a piece of Teflon tubing in the upper threaded part of the extruder assembly and I had actually burned it right out, filament was constantly getting clogged without it and it was a massive pain until I got a new one and realized my mistake.

[PepCo_Parker]

Also if you live in Canada, depending where you are, I would highly recommend ordering your filament from filaments.ca, they do a great job, I’ve probably ordered upwards of 15kg from them

[SummersideGuy]

Ok I cut 2 10 meter sections off the roll. I then spent 5-10 minutes pull the twist out of each section. I was able to get 2 successful prints from both pieces after doing this, so maybe the roll is salvageable

[SummersideGuy]

On their website the majority of their pla is sold out

[ldanut]

I would do two things:

- check if extruder gear is not filled with grinded filament that will make it slip

- try a good quality filament since yours looks like a low quality one