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frederiekpascal

why o why again...

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hey guys,

I know that I don't need to post each problem with my printer. :)

But this problem is going on for a few days now....

First I thought it were software settings, the PTFE, a broken tube, a clogged nozzle or a bad filament.

But I changed everything and the problem continues...

The problem with this issue is that I can't seem to find an answer in the troubleshoot guides (UM & Simplify3D).

gjs4KLv.jpg

If the printer wouldn't have started with extruding than solving this would be a lot easier for me.

But he keeps printing most of my brim layers and afterwards he stops extruding.... (PLA - 210°C - 40 mm/s) and the filament is completely grinded.... Sometimes the filament is so hard stuck in the bowden tube that I have to ask a colleguea here to hold the bowden and I have to pull as hard as possible to get it out. The reason why it's so hard to pull it out is because there is a blob at the end of the filament which causes the printer to stop extruding.

I also did some tests with the pressure of the filament feeder, but that didn't help either. Also tried different models, different speeds and temperatures. I re-leveled the bed a few times also, etc etc :D

Like said, I changed the tube, the PTFE coupler, the nozzle and the filament

Thanks for your help people, I don't know how to solve this one. :D

Edited by Guest

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Just wild guessing. Make a photo of the head to see if you left the 1mm gap between the stainless part and the ptfe coupler. That if too loose or too tight can make a gap or make more preassure I think...

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I'm with neotko on this one. I suspect that there's a small gap between the PTFE and the hotend causing plastic to leak out into the gap and locking things in place when it cools down.

Another option is that the third fan isn't running but I think that should be causing issues a bit later on in the print.

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Just wild guessing. Make a photo of the head to see if you left the 1mm gap between the stainless part and the ptfe coupler. That if too loose or too tight can make a gap or make more preassure I think...

 

possible but i got an L2K insulator in between my coupler and the stainless part, so the gap is bigger than 1mm, it always worked before like this...

anyway, this is my printhead :

EQ3HTa3.png

Edited by Guest

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I'm with neotko on this one. I suspect that there's a small gap between the PTFE and the hotend causing plastic to leak out into the gap and locking things in place when it cools down.

Another option is that the third fan isn't running but I think that should be causing issues a bit later on in the print.

 

I got an Olsson block with the other upgrades from 3Dsolex, I probably forgot to mention that. And my TF2K teflon is pushed correctly in the hot end coupler. (there is a L2K insulator in between though)

The 3rd fan is also running, I checked this :)

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The other area where filament residue can place it's on the barrel of the hotend... I think that's what @dim3nsioneer suspects

 

I opened up my UM2 today to check the PTFE (it was still snow white on both sides and no deformation) and there was no filament in my hotend. (you mean this part right?)

All there parts on my printer are from 3Dsolex fyi.

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I wonder... I thought about this but never got the time to do it. @dim3nsioneer @IRobertI has anyone ever think about doing a gcode ending sequence that makes an auto atomic?

Something like

Gcode allow cold extrude

Wait for X temp

g1 e-X F fast initial speed

G1 e-X(10cm more) F slower speed

Gcode disable coldextrude

Ofc it would need tweaking to find the good speeds to make it right but sound doable?

Edited by Guest

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I have thought of it also.

You would also need to keep some pressure on the filament as it cools so it doesn't ooze and cause air pockets in the head.

I guess you would risk grinding but would be an interesting test.

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@neotko: My thoughts went the same way as @Labern's. I really would appreciate to have an automated cold pull as I always remove filament that way (the change filament routine of the UM2 is useless for me as it always produces a filament strain inside the Bowden tube which then blocks the filament flow.

@frederiekpascal: This might also be a source of your problems by the way... and @neotko was right with his assumption: the shape of the filament end is interesting - especially at the spots where there are transitions from one part of the hotend to the other. At the right temperature you might e.g. see a tiny gap which could result in a clog. The other advice I always give concerning clogs and chronic underextrusion is to use something to clean the filament before it enters the feeder.

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An atomic pull device that is external of the printer for when you have just removed a nozzle could be doable.

would be nice to also have something clean up the outside of the tip 2.

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@neotko: My thoughts went the same way as @Labern's. I really would appreciate to have an automated cold pull as I always remove filament that way (the change filament routine of the UM2 is useless for me as it always produces a filament strain inside the Bowden tube which then blocks the filament flow.

@frederiekpascal: This might also be a source of your problems by the way... and @neotko was right with his assumption: the shape of the filament end is interesting - especially at the spots where there are transitions from one part of the hotend to the other. At the right temperature you might e.g. see a tiny gap which could result in a clog. The other advice I always give concerning clogs and chronic underextrusion is to use something to clean the filament before it enters the feeder.

 

Thanks for your feedback. I forgot to mention, I also replaced the bowden tube and the problem continued...

As of today (after +750 printing hours in 4 months) I always use the "change material" on my UM2 when I change filament, I probably should start following this procedure? (found on 3dverkstan)

Doing it the lazy way

Now that you've read how to do the Atomic the traditional way here's an alternative method that you can do as well. We like to do this every time we change material. Instead of removing the bowden tube you can actually just push and pull filament at the feeder end. As long as the feeder motor is powered down (easily accomplished by power cycling the machine) it's not difficult to manually push filament into the hot end or pull it out.

So what we do when changing filament is to heat the print head up to printing temperature. Then push filament manually until it starts coming out of the nozzle. Then lower the temperature and finally pull the filament out with a quick tug once the temperature reaches ~85-90C. When you now insert the new material you wont have to flush the old colour out, you'll get the new colour immediately and you will have cleaned the nozzle at the same time.

You should snip off the cone shaped tip of the old filament as it will be slightly thicker and can be difficult to load properly.

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Indeed. To manually pull the filament you might want to change to IRobertI feeder. Ofc users install it when they have problems, but the most instant improvement it's that you can 'release' the filament and push/pull manually.

Edit: So many typos omg...

Edited by Guest

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Indeed. To manually pull the filament you might want to change to IRobertI feeder. Ofc users install it when they have problems, but the most instant improvement it's that you can 'release' the filament and push/pull manually.

Edit: So many typos omg...

 

I don't think you might want to change to @IRobertI's feeder, it is a must. With the stock Ultimaker 2 I don't think you can push the filament in, and pulling it out can damage your electronics with the current it generates through the feeder-motor.. (I believe. No?)

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I don't think you might want to change to @IRobertI's feeder, it is a must. With the stock Ultimaker 2 I don't think you can push the filament in, and pulling it out can damage your electronics with the current it generates through the feeder-motor.. (I believe. No?)

 

You can push it in. I've loaded that way since the UM2 first came out. It takes a bit of force to get it to "open up" though so for me it usually means I have to use two hands. But that's only when you load completely new filament in. Pushing and pulling the filament when it's already inserted is easy as long as the motor is powered off.

I've done the "lazy atomic" on all three of my machines here at home (many, many times), I've done it on all the demo machines at work and on every single machine I've tested before being shipped to a customer. Either I've been extremely lucky or it's not an issue.

And the same could be said for moving the head around manually. That also creates current that gets fed "backwards" to the board (it's enough power to light up a 3W LED I've put on one of my machines).

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True that led light, my PWM external control connected to the 19-24v when the machine it's off and even unplugged, if I push down the bed the led goes on. Been wondering for months if that was good or bad or neither XD

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If i recall correctly the UM2 should have protections in place for moving the motors by hand. The UMO not so much.

I havent read all replies, but you might want to try and loosen the feeder screw a bit. Having it too tight can cause grinding.

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