Cloging of the nozzle and bowden cable slipping out!

[odvratno.zgodan 0]

Hi everybody. I have been a proud Ultimaker owner for some months now. A few days ago I started having problems with the extrusion head blocking. The bowden cable starts to pull out for a few millimeters and in the place between the bowden and the PEEK pla starts to clog it. After that happens it is extremely difficult, practically impossible, to push the filament. The print temperature is OK because I tried to feed the filament before printing by turning the extruder gear. It ran VERY smoothly.

I have disassembled the extruder head 7 times in the last two days and I really don't know what else to do. Every time I unclog it and try to print something it clogs in a mater of minutes.

Here is what I have done so far:

- As my UM isn't working I asked a friend to print me a Bowden clamp so now I have the white clip and the bowden cable in place.

- I think it's not a software problem because I tried slicing the model in netfabb and in skeinpypy and the problem persists, although skeinpypy retracts some of the filament before printing(any ideas)

- Cleaned the nozzle 7 or 8 times until it was totally clean(did it with compressed air)

I suspect that as the extruder pushes the filament there is a buildup of pressure on the bowden tube and it starts to pop out.

Here are the pics of the extruder head. The start position of the bowden tube is marked with a red line so I could measure how much it pulled out.

[Daid 303]

At what temperature are you printing? Also, make sure the bowden tube is nice and straight at the end (I see a small "gap"), and sticking out far enough so there is no posibility for the filament to get between the tube end and the PEEK.

The tube should not slip. But if it does, the clamp from Owen might help. Look for it on thingiverse.

[odvratno.zgodan 0]

At what temperature are you printing? Also, make sure the bowden tube is nice and straight at the end (I see a small "gap"), and sticking out far enough so there is no posibility for the filament to get between the tube end and the PEEK.

The tube should not slip. But if it does, the clamp from Owen might help. Look for it on thingiverse.

Can you tell me on which picture you see the gap? If you meen the angle of the tube on picture 2 it's not bent, it just looks that way.

I'm printing at 200C. I know that the temperature is right because after uncloging the nozzle and putting it back together, I tried manually to push the filament and flows very nicely. I also have the bowden clamp by owen and the white clipper near the hotend. There is no gap at least before it starts printing. I know the tube should protrude exactly 8mm so I measured it with a caliper before assembly.

Also what should be the length of the bowden tube? Can I cut 1cm where it's weared out so the white clip has a better grip?

[Daid 303]

On the 2nd picture, but it might also be the camera angle.

200C is good. I can print at 190C with 100mm/s on 0.1mm layers.

I don't know if exactly 8mm is enough. My alu plate is not connecting to the wood because my tube is slightly too long. This ensures I have a very good connection between the PEEK and the tube. You can use your caliper to measure the depth of the PEEK. Maybe 8mm is slightly to little.

Cutting off some tube will improve the grip. Maybe you can also widen the end of the tube a bit so it's a bit larger and the clip will have better grip on it.

[odvratno.zgodan 0]

Hmmm, might be that 8mm is not enough, though it worked till now. I blindly followed the instructions from the assembly manual so I will try to make it a little longer. Also I will cut 1.5cm from the end so it has better grip.