Filament Grinding Problems

[echox 0]

Hi Ultimaker board!

We have an ultimaker since ~ 7 months.

In that time we collected some experience with the machine itself, preparing prints, material, etc.

The print which took the most time was the upper part of the Tie Advanced X1 model from Thingiverse (

http://www.thingiverse.com/thing:14480

) which took about 9h with a layer height of 0.1mm and 100% infill.

The ultimaker worked without any problems.

Since some weeks printing has become the opposite of fun, because I invested days of debuging the machine...

The problem:

After ~ 15 Minutes the filament seems stuck. The feeder is still running and grinds into the material.

Results look similar to that picture:

http://img38.imageshack.us/img38/6213/cam00010.jpg

If I push the filament into the feeder, the screw with the knurl will get grip again, and printing works for ~ 2 minutes.

Then the problem occurs again.

Hardware modifications:

 

• 
  [*:29p98pdc]Hot End V2
  [*:29p98pdc]Feeder Upgrade with bearing:
  

http://www.thingiverse.com/thing:21674

 

Things I tried:

 

• 
  [*:29p98pdc]Slicing the .stl Files with different settings and slicers (Cura/slic3r)
  Measured Steps-per-E at 900, but tried Settings between 880 - 920
  Tried printing speed between 100 and 120.
  [*:29p98pdc]Printing PLA between 180 and 215 degrees
  [*:29p98pdc]Changing PLA (tried 6 different colors/types, including two spools of the 'pink' ultimaker PLA)
  [*:29p98pdc]Changing hot end (V1, V2) and vary nozzle size between 0.4 and 0.6
  [*:29p98pdc]Trying some custom made hot end:
  

http://log.raumzeitlabor.de/post/366808 ... -falschung
[*:29p98pdc]Trying to use the original feeder clip, which made the result much worse
[*:29p98pdc]Turned off fan at printing head
[*:29p98pdc]Cooling the motor drivers on the buttom with a much colder ;-) custom fan
[*:29p98pdc]Changing the bowden tube
[*:29p98pdc]Firmware Upgrade
[*:29p98pdc]Printing without the Ulticontroller
[*:29p98pdc]Double checked for any narrowings on the way from the feeder to the print head
[*:29p98pdc]Cleaned everything on the feeder...

 

Mainboard revision is 1.5.6 JJ/SW/EdB.

Firmware is Marlin 1.0RC2.

Firmware Configuration is this one:

http://daid.eu/~daid/marlin_build/ ... dSupport=1

Any help would be appreciated :-/

[snowygrouch 1]

Thats a pretty exhaustive list of things changed !

I would recommend that you do this:

1) Heat up the hotend to whatever temp you normally print at

2) Unclip the rear of the extruder so the wheel isnt clamping the filament

3) Push the filament through the bowden and hotend by hand, this should be no trouble at 220 or 230. Get

a feel for how much force is needed to do that.

4) Now print as normal until you get the griding.

5) quickly repeat step 2 and 3. Notice if the filament is possible to push through by hand. If its much much harder

to push though, or even impossible you know you have a plugging problem. If its just as easy as before, then you know

you have an extruder problem.

This will at least show you which end of the machine to investigate.

If its the hotend, it means you have an assembly problem, probably the position of the bowden or the end not

being cut square. Also I personally have a fetish for active cooling on the hotend, and maintain its the only

way to print 100% reliably all day long. However...most people seem to find the V2 hotend to be "ok", so you should be

able to make it work.

If its the extruder, you need to sort out your spring force, get a better knurled bolt, or check the position

of the knurling. The UMaker one is really badly made and the knurling is tapered in depth, so along the width

of the knurling only the last 3mm is actually nice and sharp. The rest is just blunt. If the bolt is shuffled

too far one way, you might be running the filament against the blut area of the knurnling. Have a look at that.

Of course its possible its BOTH ! But I think by doing the above test you will see where the real issue is.

(shameless corporate angling follows)

If its plugging you are suffering from I would recommend downloading the STL from my website and putting a fan to cool the hotend. It costs almost nothing to do, and you will never have a plug again.

Regards

C.

[felicitus 0]

Hi,

disclaimer: I belong to echox, this is the RaumZeitLabor Ultimaker.

After opening up the hotend, I've found quite a bunch of PLA stuck in there. This is the V2 hotend with that little white thing between the bowden cable and the hotend. I'm not sure what happened here, but isn't the V2 hotend supposed to fix nozzle jams?

EDIT: After cleaning the hotend and retry printing, the nozzle is jammed again after no more than two minutes. It seems that the gap between the white thing and the PEEK insulator is simply too big.

EDIT2: I noticed that the brass tube wasn't connecting to the white plastic thing, so it's obvious why there are blobs in the print. However, Filament is still slipping. Not sure if it's a jammed nozzle again, but I don't think so, as I can manually push the filament further if it is slipped. Printing speed is currently 70mm/s with a layer thickness of 0.3mm (due to the 0.6mm nozzle)..

regards

Felicitus

[joergen 2]

EDIT2: I noticed that the brass tube wasn't connecting to the white plastic thing, so it's obvious why there are blobs in the print. However, Filament is still slipping. Not sure if it's a jammed nozzle again, but I don't think so, as I can manually push the filament further if it is slipped.

There must not be no gap between the brass tube and the white teflon connector... if there is a gap, check your assembly instructions... the longer end of the brass tube goes into the PEEK all the way, until the flange is flush with the peek.

[felicitus 0]

There must not be no gap between the brass tube and the white teflon connector... if there is a gap, check your assembly instructions... the longer end of the brass tube goes into the PEEK all the way, until the flange is flush with the peek.

I just fixed that, filament is still slipping through the feeder. Looks like I have to disassemble the head again, or try the spring screw feeder...

[msurunner 2]

I don't think you are running at a high enough temp for the print speeds you are attempting. I would say try a print at 225 and see what happens. This ought to make it "easier" for the extruder to push the filament through the hotend.

[billdempsey 0]

My two cents: I found with the gold filament that too much heat also created plugging after a period of time. The problem is that the higher heat is conducted further up toward the bowden. In the case of the gold filament, I was able to reduce the heat from 220C to 195C and still get prints. But, the best way around this type of plugging is to have a fan blowing through the space between the aluminum plate and wooden bottom plate. It keeps the heat down at the hot end, where it belongs. It lets you run higher temperatures for finicky PLA without the plugging issues. I believe the link Snowygrouch gave will let you download a fan mount for this type of setup. Highly recommended!

[johank 7]

Hi, It sounds as though you're trying to push a really large amount of plastic through the hotend (? 70mm/s * 0.3 mm * 0.6mm ?). Is the hotend really able to keep the temerature up? Perhaps someone with some experience simulating heat flow could give an answer, but the measured temperature is of the heating block, not the plastic.

[zxen 4]

The feeder grinding occurs due to the nozzle being blocked and causing a traffic jam. It takes hours to clean the nozzle and sometimes it is impossible without a sewing kit. I bought a replacement. That just got blocked too :(