Spool Knots

I've lately been getting a lot of knots on the spool where it gets tangled as the printer pulls on it, causing the print to fail (it just keeps printing without filament).

This happened around hour 19 of a 22 hour print and hour 7 of a 10 hour print, on an Ultrat spool.

I've tried loosening the filament before the print and at intervals but its not enough, any ideas?

I've also had this issue. It has only happened to me when using Z-ABS. 

Happened to me too… Some spools are good, others are not…

Happened once to me too with dark blue Z-ABS.

Only happened once to me with Android green.

Happened to me yesterday after 10 hrs of a 17 hr print.

It's happened to me twice in perhaps 50-60 prints with two different colors.  Both times it looked to me like the knot was produced while the filament was being wound onto the spool.

I am new to 3d printing, but I am a pro when it comes to all forms of extrusion. Many of the issues that customers are having with knots in the spool can be coming from unloading the spool and letting the end piece snap back. You should keep both hands on the spool at all times when loading and "ESPECIALLY" unloading the spools. It is "VERRRRYYYYYYY" hard to wind a spool and get knots in it. There is really only one way to do that, and that is if when they cut the spool they do not hold the end piece, otherwise you would have a splice in the spool. If the problem is happening at either the beginning or end of a spool, then and only then it "could" be a manufacturing problem. But if it is not happening at the beginning or end, then it is most likely user error.

Moral of the story take care when loading and unloading filament, if you let go of the end and it snaps back then there is a good chance you will have knots. But as far as manufacturing goes, it is most likely done in a continuous run so that would make it very hard to create knots. 

If it is a manufacturing problem, then I ask Zortrax to get rid of the manufacturer and let me run and store the filament in the US in a "Medical tubing facility". Complete clean room 100% virgin materials.

Richdon is right - almost every problem with spool is caused by inattentive loading/unloading filament. Please do not let the filament unwind on the spool - use holes in the spools (or buldog clips if you wish) to secure the end of the filament.

See the quick photo of used filament below. Blue filament on top was not secured and will cause problems while printing. Grey filament was properly secured - the end of the filament is hold by the holes in a spool and the filament have no possibility to unwind.

4nlEu6Fl.jpg

Filip,

Would it be possible to have a couple more holes in future spools?

@Andre

We will see what we can do. :)

Hej, 

just use clips: http://www.thingiverse.com/thing:386570 - works just great :) And don't let filament go, if you do, unwire few turns to check for knots.

This information would have been very helpful if it came together with the printer instead of after several wasted spools..

Zortrax - how about including an index card with the printer or with each spool? Im sure I was not the only one having this problem.

Just thinking out loud here - Richdon and Filip, if what you say is true, then how could it have happened on hour 19 of a 22 hour print, long after any slack in the spool was gone?? (long, long after, and on a new spool)

Nice to try to get responsibility off your back, but not so easy when you apply a little critical thinking.

Well, I would have to say that, that one is hard to explain away, but unless someone was either the dumbest operator, or intentionally tried to mess up the spool, it would be very hard to get a quote knot in the middle of a spool.

Use critical thinking and you will realize that it is not possible to do that with a continuous run . Now they might of gotten slack in there spool and it might of kinked, but that is it. (maybe there not doing continuous runs I do not know)

Or maybe as I stated above they might have "not" held the end of the spool when they cut it, the same as many of us do, what this will cause is a back lash of the filament, and YES it could in that case have a "knot" in the middle of a 20 hour print. (although 20 hour print is not really relevant, I mean a 20 hour print could be 100 grams of filament or 300 grams of filament.) If the end of the filament snaps back it could easily get wrapped up enough to where it will run and continue to pull until it finally hits a stopping point. Don't think that the filament will stop as soon as it reaches the "knot", the knot will continue to move backwards until it reaches a point where the resistance is to strong especially if the spool is already loose from the snapping back of the end piece. And unless you where watching the spool the entire time, you really do not know when "all" the slack was out. Look at the blue spool above I'll bet you that, that is at least 200 grams of slack in that spool, and on a new spool that same amount of slack would be even more, because there is more surface area the larger the spool.

Finally, I personally, do not work for, with, around, or near Zortrax, So I have no reason to try and push responsibility off my back or there back. If you had really used critical thinking you would have realized that. 

Also I will say that Filip said,:

"Richdon is right - almost every problem with spool is caused by inattentive loading/unloading filament."

I said:

"Many of the issues that customers are having with knots in the spool can be coming from unloading the spool and letting the end piece snap back."

Not once did he or I say that "ALL" problems are caused by user error.

Sorry if this comes off as a little rude or abusive, trust me it was not meant to be that way, I just get tired of people always thinking someone is trying to get over on them. The world is not out to get us all the time, maybe zortrax has some flaws here and there but tell me which company, or person doesn't. 

PS please "TRY" to ignore my poor English Grammar above.

Or maybe as I stated above they might have "not" held the end of the spool when they cut it, the same as many of us do, what this will cause is a back lash of the filament, and YES it could in that case have a "knot" in the middle of a 20 hour print. (although 20 hour print is not really relevant, I mean a 20 hour print could be 100 grams of filament or 300 grams of filament.) If the end of the filament snaps back it could easily get wrapped up enough to where it will run and continue to pull until it finally hits a stopping point. Don't think that the filament will stop as soon as it reaches the "knot", the knot will continue to move backwards until it reaches a point where the resistance is to strong especially if the spool is already loose from the snapping back of the end piece. And unless you where watching the spool the entire time, you really do not know when "all" the slack was out. Look at the blue spool above I'll bet you that, that is at least 200 grams of slack in that spool, and on a new spool that same amount of slack would be even more, because there is more surface area the larger the spool.

137

knots1.jpg

As proof to my statements, I took a spool of Makerbot filament, (a new roll) and intentionally let the spool get a little tangled. (maker bot filament is not wound as tight it would appear, so the back lash wasn't as much.) But none the less I took it and overlapped it by 5 strands. Then I pulled off roughly 80 feet of filament (roughly 60 grams of abs at 1.060 g/cm) and It still didn't stop, so like I said it will go until tension gets to high.

So critically thinking (logically thinking) yes you can go 19 hours out of a 22 hour print before it binds up on you even if it is operator error.

Now I have to re-wind this stupid makerbot roll. but anything for the sake of knowledge. 

lol thanks for trying that out. I didint mean that for you, more for zortrax which seemed a little too pleased to just attribute it to user error.

But anyways, I thought that when they are winding it if they criss cross it then it would be quite easy to mess it up, wouldnt it?

In any case being more careful from now on ;)