UM2: Clicking and skipping filament

[jjshortcut 0]

Hi,

 

Since the last 2 weeks I'm having trouble printing on my new UM2, the extruder is not extruding enough filament and I hear the clicking noise frequently. The extruder motor is skipping steps/not enough torque/current.

I've already done the things which are subscribed for this issue;

 

- Tighten or losen the filament screw; both done, nothing works..

- Clean the nozzle; done, nothing in there

- Clean the extruder assembly; also nothing in there only the ball-bearing has some friction unto the plastic case.

- Push filament by hand is really difficult, even at 230 deg c.

Anyone has a clue about what to do? Can I adjust the current setting for the steppers?

JJ

 

[gr5 2,005]

It's very likely not the extruder in my opinion. Even though the nozzle is "clean" there is probably some ABS or other gunk stuck to the inside wall. To prove whether the problem is the extruder or not you can do this test:

http://umforum.ultimaker.com/index.php?/topic/4222-pulling-force-of-um-extruder/?p=34887

Is it possible that the filament is more than 2.99mm? Once filament hits about 3.00mm it tends to not be able to pass through the bowden.

To clean your nozzle more thoroughly I recommend getting some metal that can fit in the nozzle such as hypodermic or acupuncture needle and doing this:

http://umforum.ultimaker.com/index.php?/topic/4118-blocked-nozzle/?p=33691

 

 

[jjshortcut 0]

I already tried the nozzle cleaning the way you described, I let a piece of PLA smelt in the extruder and pulled it out at 80 deg which helped me pull out all of the inside plastic in the extruder. I got a perfect shaped extruder inside form, even with a small top piece of .4mm so I'm sure it's clean..

I've only used PLA on this printer from ultimaker which is approx. 2.85mm.

I did the pulling force test and the machine skipped steps at 2KG and later at 3KG.

It feels like the extruder motor has not enough current and the heated block is just not heating the filament quickly enough..

 

[mtmvetultimaker 1]

I have the same problems everyday...

probably is the filament diameter that must be 2.85mm. I tried to buy filament from Ultimaker, but as usual, they are out of stock, in spite of accepting the order and charging my CC...

Another problem is the bowden tube. If is just a little bit out of place (mainly near the nozzle), it will start an under extrusion and the clicking noise starts damaging the filament . My printer came with the bowden tube clips damaged, therefore I always have the problem.

regards,

Mario

 

[gr5 2,005]

I've only used PLA on this printer

 

I know but it's possible for some pieces of ABS to get into the nozzle. But that doesn't sound like your problem.

 

Push filament by hand is really difficult, even at 230 deg c.

 

I guess I don't understand that comment. Could you explain further? I thought you meant with the head taken apart.

2-3kg is not great. Mine will pull 5.5Kg which is 2 to 3X what yours can pull. So assuming 1/3 (for margin) and looking at this table:

http://umforum.ultimaker.com/index.php?/topic/4127-um2-extrusion-rates-revisited/

you should be able to print max speed of 30mm/sec with 230C and .2mm layers.

I think you should take the extruder apart. Another person had a little piece of PLA filament stuck in the extruder mechanism and it wasn't closing on the filament properly. Take pictures if you learn anything. You want the extruder at it's weakest tension. You don't want the screw in there doing anything - the spring is a little too strong as it is.

 

[jjshortcut 0]

 

Push filament by hand is really difficult, even at 230 deg c.

 

I guess I don't understand that comment. Could you explain further? I thought you meant with the head taken apart.

 

Well, I took apart the extruder and heated it to 230 deg. and pushed filament through, but this was very difficult to do, way more difficult than with my UM original..

 

2-3kg is not great. Mine will pull 5.5Kg which is 2 to 3X what yours can pull. So assuming 1/3 (for margin) and looking at this table:

http://umforum.ultim...ates-revisited/

you should be able to print max speed of 30mm/sec with 230C and .2mm layers.

 

I did print .2 layers, 230C and it even ticks at 25mm/sec (printing a 30x30mm cube 100% fill) whereas my UM original can do 80 with ease..

So I took apart the feeder mechanism again.. and here are my findings; Aparently the filament is grinding into the plastic part which lead to friction.. this is caused by the sping being to strong/long and pushing the filament into the pastic part. Notice that this happens on both before and after the motor. Now I took the tension away, removed the nut and bolt and and now it prints fairly ok, 230c, 40-50mm/s, still not near the 90mm/s..

Here a photo of the grinded plastic feeder mechanism; http://s29.postimg.org/ikrztirzb/CIMG1392.jpg

 

[illuminarti 18]

Possibly some of that ground away ABS ended up in the hot end, blocking it partially?Try heating the head to 250, and run some PLA through it - perhaps do a print at 250. That might help melt and flush out any ABS in there.

 

[gr5 2,005]

Flushing out ABS from inside the nozzle is not easy. Sometimes if you print a meter of PLA at 250, occasionally a piece of ABS will come out and you can get it all out. Sometimes you have to take the nozzle off and soak it in acetone. Sometimes you can do a thorough nozzle cleaning with this method:

http://umforum.ultimaker.com/index.php?/topic/4118-blocked-nozzle/?p=33691

 

 

[jjshortcut 0]

Possibly some of that ground away ABS ended up in the hot end, blocking it partially?Try heating the head to 250, and run some PLA through it - perhaps do a print at 250. That might help melt and flush out any ABS in there.

 

That's what I did a few times already.. is it normal that it grinds into the extruder mechanism, probably not.. so the spring is tightning the filament to much.

I printed the tightning mechanism a little shorter (the white part in which the nut and bolt are connected) and now the tension on the spring is less, and I'm more capable of regulating the spring tension instead of lowest spring tension always. This works so far but still it cannot do more than 60mm/s. Pics;

http://s30.postimg.org/6m0c2djqp/photo_1.jpg

http://s30.postimg.org/wga4s5jqp/photo_2.jpg

What is normal for the UM2 to be able to print? And is there anyone who has the same issue with the grinded extruder feeder part?

 

[Nicolinux 288]

Hey jjshortcut, we might have the same problem. Might I point you to my monster thread where many people contributet quite some ideas? (http://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/).

Another issue could be the teflon coupler that sits on the nozzle. Have you checked that? You say that you can barely push filament by hand which means the problem must be further up the bowden tube (head probably).

 

[jjshortcut 0]

Thanks for pointing out that thread, I'm gonna read it.. I havend checked the teflon part yet, it seems ok but I haven't checked it very carefully..