Feeding Problems

[TheGiffMan55 0]

Hi all,

So recently I've been having some material feeder problems and I have managed to determine that nothing is wrong involving the nozzle (that I know of).

For some reason the feeder likes to jump back every few seconds, not sure the problem there. Is the problem with the filament or feeder itself?

My theory is that there is something wrong with the feeder "block" itself so to speak. When I try to adjust the tension with the screw on the top of the block, the little white tension indicator bars don't move. Is something missing or broken?

Apologies if this problem is blatant, still new to 3d printing.

Thanks for your time.

[gr5 2,265]

Do a google image search on the feeder to see how the tension is controlled so you can see what is inside - once you do all is obvious.

But that's probably not your problem. The feeder is purposely given less current so it only has about 10 pounds or 5kg of force. Any more and the filament gets ground up. So the first thing to check is what temperature, speed, layer height are you printing at.

Here are my recommended top speeds for .2mm layers (twice as fast for .1mm layers):

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

Also check your temp sensor because they can easily be off by 10 to 30C:

 

[TheGiffMan55 0]

Do a google image search on the feeder to see how the tension is controlled so you can see what is inside - once you do all is obvious.

But that's probably not your problem.  The feeder is purposely given less current so it only has about 10 pounds or 5kg of force.  Any more and the filament gets ground up.  So the first thing to check is what temperature, speed, layer height are you printing at.

Here are my recommended top speeds for .2mm layers (twice as fast for .1mm layers):

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

Also check your temp sensor because they can easily be off by 10 to 30C:

 

 

Hi gr5

I did forget to mention that the feeder makes a moderately loud beeping noise when I'm in the 'move material' setting, not sure if that has much to do with anything. As for the print settings, very helpful will definitely use them as I've been printing too cold. I've been doing 40mm per second at 210C. I generally use 0.1 for layer height.

[gr5 2,265]

If you read my post again you should be able to go up to 120mm at 210C but I recommend no faster than 60mm/sec with .1mm layers at 210C. So 40mm is well within the max of 60mm.

Try testing the temperature next using my video as a guide.

Here is a longer list of possible causes of underextrusion:

2) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 100 hours. It warps. It's the white part touching the heater block. Test it by removing it and passing filament though it by hand.

3) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

4) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

5) Head too tight? Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine! Has to do with pressure on the white teflon isolator.

5b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

5c) Spring pushing too hard. Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

6) clogged nozzle - the number one problem of course - even if it seems clear. There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame.

8) feeder spring issues - too tight, too loose

9) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well. Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip. Gunk clogging the mechanism in there.

10) Filament diameter too big - 3mm is too much. 3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05. But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker. It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out. Throw that filament in the trash! It will save you weeks of pain

10b) Something wedged in with the filament. I was setting up 5 printers at once and ran filament change on all of them. One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly. I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that got jammed in the bowden tube.

[TheGiffMan55 0]

If you read my post again you should be able to go up to 120mm at 210C but I recommend no faster than 60mm/sec with .1mm layers at 210C.  So 40mm is well within the max of 60mm.

Try testing the temperature next using my video as a guide.

Here is a longer list of possible causes of underextrusion:

2) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 100 hours.  It warps.  It's the white part touching the heater block.  Test it by removing it and passing filament though it by hand.

3) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

4) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

5) Head too tight?  Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine!  Has to do with pressure on the white teflon isolator.

5b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

5c) Spring pushing too hard.  Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

6) clogged nozzle - the number one problem of course - even if it seems clear.  There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove.  Sometimes a grain of sand gets in there but that's more obvious (it just won't print).  Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame.

8) feeder spring issues - too tight, too loose

9) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well.  Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip.  Gunk clogging the mechanism in there.

10) Filament diameter too big - 3mm is too much.  3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05.  But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker.  It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out.  Throw that filament in the trash!  It will save you weeks of pain

10b) Something wedged in with the filament.  I was setting up 5 printers at once and ran filament change on all of them.  One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly.  I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that  got jammed in the bowden tube.

 

Thank you very much gr5 for your help, fixed my problem. I now have a functional 3d printer again

[macua85 52]

For others if they have the same problem, how did you fix it?

[larsgw 2]

I'm running into the same problem now. Brand new UM2 extended (not extended plus - I have the upgrade kit on order). I printed 3 things on it, and all of them came out well.

Until this morning. I re-leveled the bed and I started printing. The printer seemed to start okay, and got about halfway through the raft, then I heard it making an odd noise every second or so. I walked over and found the head still moving but nothing coming out of the extruder...and at this point the raft looked like hell, and nothing was coming out of the extruder. I did notice the feeder in the back was slipping. The filament would move about a quarter inch, then slip back. I took the filament out and found this:

I followed web advice and detached the bowden tube ends to check for blockages. I pushed some filament into the nozzle end at it came through fine, so it seems to me the issue is something to do with the material feeder.

I was wondering if it's okay to take those four hex bolts out and open the feeder up to try to clean the area around the gears out if they need it. I don't want to take those little bolts pout and hear something fall inside the printer.

[donmilne 2]

Be very careful about taking the bolts out - you will indeed hear something drop down inside the printer, because the stepper that drives the filament is held on by those same bolts!  Be careful too about the contents of the feeder case - things will drop out of there too. Don't panic, you'll work out how to put it back together. In the past I would have recommended replacing the hopeless stock UM2 feeder with Robert's one, but if you have the UM2+ upgrade kit on order then that's maybe not worthwhile.

Basically, grinding happens when the pressure required to push the filament is greater than the failure force of the filament (considering the minimal contact that the knurled wheel has with the filament).  In fact on the UM2 you normally get skipping before you get grinding (both result in failed prints). There can be lots of reasons for excessive back pressure from the extruder: using too low a temperature (you learn what particular filaments need), using too high a speed, too much tension on the feeder, too much curl on the filament causing friction inside the bowden tube etc. There can be other explanations that don't usually apply to a new printer (e.g. deformed teflon tube after many ABS prints, or after printing at too high temps).

Edited March 20, 2016 by Guest

[larsgw 2]

Thanks for the quick and informative reply. I'll hold off on removing the feeder until the replacement arrives. This is my first 3D printer and I'm not in a hurry to visit it's guts without a solid set of instructions.

I have to say one of the things that sold me on getting an ultimaker was the robust community around them. You didn't let me down!

[cloakfiend 996]

Dont be afraid, do it. Just slide a normal sized ruler behind the feeder motor and it wont fall out, i find it to be an almost perfect fit, you may need to bend it a little just to make it flush when you are putting it back but it nothing to be afraid of and wont affect your prints. Ive taken mine off loads. Its the first thing i did. I personally have no issues.with that feeder apart from it being closed so i cant fish debris out without taking it off. There is just one spring inside and a white thing and if you are careful nothing will fly out (and there are loads.of photos atound of it so dont worry). Id just give it a good blow with an air duster unles you are sure something is stuck. Id take it off just to get used to not being afraid of taking if off as otherwise its something to fear. Dont worry its not delicate and there is zero chance of you damaging anything in there even if you do it when your drunk!

You will need to take stuff apart eventually and to maintain it so wht not start with one of the easiest and safest parts to remove? After all, youre gonna do it any ways.

Oh yeah, just make sure you dont put it on backwards then everything happens in reverse, lol!

Edited March 20, 2016 by Guest

[bob-hepple 59]

Larsgw

sorry to say it but you found the week link in the machine, I would tighten the tension hold your breath till the new extruder arrives, you will be less frustrated in the end. It is an issue and it is well documented. I had my machine for 2 years and it was documented then. I hear the new feeder is much better, I found to help with this problem is to increase the heat carefully and slower your print.

sorry to be a bit gloomy but your problems is what I have had for months.

Good Luck

[donmilne 2]

If you're going to do it right away then I really wouldn't put the old feeder back: while some may struggle along with it, there are better designs which mean you don't have to struggle. The one I use is this variant on Robert's design :-

https://www.youmagine.com/designs/yet-another-ultimaker-2-feeder

I like this because it ensures that the filament is straightened out before it enters the feeder. I also add a clamshell type sponge holder that wraps around the filament and cleans off any dust from the filament (and optionally lubricates) before entry into the feeder.