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jonathan-wight

Got my UM2 Monday, Tuesday it's stop extruding

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Got my UM2 on Monday, and made a few small test prints using the provided (blue) PLA. All test prints were fine.

Today I start my first larger print (~2 hours) and it got 90% the model just fine and then decided to stop extruding. I was printing with Cura's "low quality" settings, the bed was levelled OK and I was using the right material settings on the UM2.

I've looked around the forum and seen similar-ish problems that recommend adjusting the white "dial" on the feeder. The feeder was set to the midway point but I've adjusted it both to min and max and had no longer. Some filament does extrude but it's incredibly unreliable.

Any advice?

I'm rather dismayed obviously that such an expensive printer with a good reputation failed on day #2...

 

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Hi..

What speed and temp are you printing with ?

The ultimaker2 is a very accurate and detailed 3d printer but with the existing feeder and hotend design seems to be limited in speed for many users..

Your not alone.. many people who first used the ultimaker1 noticed that the overall quality and design of the ultimaker2 is far better and reliability but for the moment until ultimaker get there feeder and hotend tweaked... you have to print hotter and slower.

You can get tons of amazing prints but those two points are important.

At the moment im getting really good prints with speed 55 temp 255 but that really does vary with different users and different filament.

Another question.. when you print.. is the back feeder clicking ?

Ian :-)

 

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Welcome, Jonathan. I'm afraid you perhaps need to moderate your expectations a little bit. 3D printing is still a cutting-edge technology, and it's inevitable that occasionally there will be hiccups. This doesn't mean the printer has 'failed' in any significant way, just that it needs a minor tweak to get it back to working great again. With a little bit of practice and experience, you'll learn how to fix these things and get working again in no time. Don't get me wrong, it can be frustrating when something goes wrong, but it just goes with the territory at the moment :-)

As Ian noted, the 'low quality' setting in Cura tries to print quite fast - it may be that it is a bit much by default, for the material or model. In any case, I strongly urge you to ditch the 'quickprint' settings, and begin to learn the detailed settings, as soon as possible. :-) It may seem a bit counter-intuitive at first, but slower, more detailed prints will actually stress the printer less, and so give more reliable results.

Secondly, I don't recommend adjusting the feeder tension screw on the UM2 to have the white indicator anywhere but at it's highest point (you need to tighten the screw into the feeder assembly, to get the indicator to move upwards). The feeders tend to have over-powered springs in them, and even the lowest tension (highest indicator position) is more than enough tension.

Finally, regarding the actual 'stopped extruding' bit. What happens? Is the extruder motor still turning? Do you see (and hear) it jumping back one-eigth of a turn, constantly - or does it keep turning smoothly, but it has simply worn away the plastic? If the plastic is worn away, then the extruder can't grip it, and you need to remove the plastic and cut the damaged part off. Do a 'change filament' operation to get the filament out - you might need to pull on the filament at first as you do that, to get it past the worn away part - and then cut the filament with a nice clean cut, and reinsert it.

 

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You may have a nozzle clog but from your description I'm going to agree with Illuminarti and go with "ground filament" at the feeder. Look inside the black feeder on the back and see if you can see if the filament is ground up.

Regarding the spring tension position - UM might be shipping printers with weaker springs so the center position might be better than all the way up - we (Illuminarti and Ian and I) just don't know at this time as we all have the strong springs.

 

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Jonathan. I'm afraid you perhaps need to moderate your expectations a little bit. 3D printing is still a cutting-edge technology, and it's inevitable that occasionally there will be hiccups. This doesn't mean the printer has 'failed' in any significant way, just that it needs a minor tweak to get it back to working great again.

While I fully understand that 3D printing is a new(ish) technology the UM2 is a _very_ expensive machine to have fail (effectively) straight out of the box. I was getting more reliable prints with my generation 1 solidoodle which was less than a quarter of the price. Anywho...

I'm currently printing using Cura's three defaults. I just tried a longish (4m) print that on "Fast" that died after the first hour. I'm now trying a different print on slow to see if that helps.

Is there anywhere that documents the exact expert settings these defaults use? I'd like to be start from a known "good" set of configuration.

 

Another question.. when you print.. is the back feeder clicking ?

 

 

Right now - printing a part on medium - there's a constant (4 beats per second?) clicking coming from I _think_ the rear feeder. The print seems to be going just fine

Is this good or bad?

 

Regarding the spring tension position - UM might be shipping printers with weaker springs so the center position might be better than all the way up - we (Illuminarti and Ian and I) just don't know at this time as we all have the strong springs.

UM support (Marrit Hoffmans) told me it should be at the topmost position...

So I've cleaned the hot end by manually feeding filament in and doing the 200° to 90° and pull out technique. I did have some trouble getting the bowden tube back in. It seem to catch and cause the filament to not feed properly - but I think I've fixed that (it's feeding now just fine).

I really don't think there's a clog. I'm relatively sure this is a feeder issue.

I'm really hoping a slower speed and maybe hotter temperature will help. At least until I print off one of the better feed mechanisms.

 

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Finally, regarding the actual 'stopped extruding' bit. What happens? Is the extruder motor still turning? Do you see (and hear) it jumping back one-eigth of a turn, constantly - or does it keep turning smoothly, but it has simply worn away the plastic? If the plastic is worn away, then the extruder can't grip it, and you need to remove the plastic and cut the damaged part off. Do a 'change filament' operation to get the filament out - you might need to pull on the filament at first as you do that, to get it past the worn away part - and then cut the filament with a nice clean cut, and reinsert it.

 

Oh at one point I noticed the axle was moving independently of the toothed gear. The little screw that tightens the gear was too loose. I've tightened that.

Next time it fails I will make sure to find out if the motor is turning.

There are some smallish chunks of filament inside the feeder casing so I'm assuming when it fails it starts stripping the filament and slips.

Now what about this ticking? Ticking good or ticking bad???

 

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A quiet ticking can be fine - it's just the stepper motor advancing. Of more concern would the noticeable clicking that happens when the extruder skips steps and jumps back (which is intended to prevent it stripping the filament). When it does that, you'll see the extruder motor shaft and sleeve jump backwards about one-eighth of a turn.

You might want to try printing the extruder test gcode, to get a sense of what speeds your extruder can handle:

http://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/?p=33427

You can load the settings from an earlier gcode in Cura. So you can create a file in Cura's quickprint mode, then switch to full settings, and use the 'Load Profile from gcode' menu option to read back the settings. A bit clunky, but it works. There's nothing particularly magic about the quickprint settings though.

To begin with, I'd recommend printing at 40mm/s, with 0.15mm layers, 0.8mm shell thickness, and 0.75mm top/bottom thickness. That should be a comfortable mid-range setting for most things. Also, on the printer itself, you might want to increase the temp for PLA to about 230º, to help it flow better. Then from that base you can start to experiment a bit.

 

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If you print the test cylinder above I recommend you look at other people's results here instead but most importantly it is designed to be printed at 230C. If you print at any other temperature it's hard to compare it to another printer. I feel anything that reaches past 5mm^3/sec is a well functioning machine although some people insist on 10:

http://umforum.ultimaker.com/index.php?/topic/4586-can-your-um2-printer-achieve-10mm3s-test-it-here/

 

UM support (Marrit Hoffmans) told me it should be at the topmost position...

 

Well...

Marritt might be right. Or she might be wrong in this case. UM started shipping weaker springs recently. I don't know how to tell if you have the original (much too strong) spring or the newer weaker spring. I guess you could do a compression test on a scale. I think you should put it back in the middle and assume the problem was that loose set screw on the knurled sleeve.

 

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If you end up doing a compression test on a scale, photograph the spring, tell me the length uncompressed of the spring, tell me the force at a given length (for example compress it to say 15mm length and measure the "weight" on a scale) then I will repeat your experiment on my (much too strong) spring and we will have at least one, but maybe 3 ways to tell them apart. I'll even tell you the force the spring makes when the feeder is at the top position.

But be warned - if you take the feeder apart the stepper will fall. Not a big deal but an extra thing to worry about.

 

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But be warned - if you take the feeder apart the stepper will fall.

Hmmm what? I already took the feeder apart to get to the tightening screw. The stepper motor did fall out of the hole a little and I had to open its cover inside the printer to re-align the stepper.

I presume that's what you meant?

 

f you end up doing a compression test on a scale…

OK. I'll try and do that this evening. Thanks. Will be adjusting the pressure on that part to see if a difference is made.

 

You might want to try printing the extruder test gcode, to get a sense of what speeds your extruder can handle:

Working on it now! Thanks.

 

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8 is pretty good. When it started to fail, was it skipping back with loud clicks, or just wearing away the filament? Looking for debris after the fact isn't always a good way to spot slipping.

And yes you can go into the PLA menu option on the printer , change the settings, and then resave it. I don't have te printer in front of me to check the exact steps, but it is doable.

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Yeah I found the "save preset" function - thanks.

Not sure exactly what was happening when the test cylinder started. I don't think there were loud clicks. I'll print it out again later and pay special attention to the faster speeds.

I'd say 7mm^2/sec is probably the upper limit. I'm testing with higher temperatures and lower speeds now.

Smallish prints all seem to be ok (and far better quality than my solidoodle could ever achieve). I'm just worried about these long multi hour prints dying on me.

Thanks for all the advice

 

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I'm just worried about these long multi hour prints dying on me.

 

Two things:

1) I think it's more reliable with the filament on the floor for several reasons I don't want to get into.

2) If a print fails part way through (say after 6 hours or 20 hours) don't let the bed cool - if you have to hit power then that is fine but turn it right back on and keep the bed warm so the part doesn't pop off. You can leave the bed at 60C (or whatever) for several days until you know what to do to continue the print. It's not too hard to continue the print. Let us know and I'll find the directions to how to do this.

filament on floor:

spool On floor

 

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