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simmonsstummer

Always blocked Nozzle @ filament change

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Ok,

the first time could be a case....

but today i tried to change material and again the nozzle seems to be blocked.

So i tried the manual movement of the filament (the one in advanced setting) and nothing..

I tried to raise the temperature.... nothing..

i tried to change the material again removing the filaments... and nothing..

What i have to do to simply change the filaments without pain?

And le me ask how is possible to remove the bowden tube to clean small filaments or pieces that can remains in the tube itself? How can i use the red Clamp Clip and a Tube Coupling Collet.

 

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Why you get a clog already? Were you using ABS? Are you printing in a dusty room? Dust can clog the nozzle. I have only gotten 1 clog and only on my UM1 and only once in a year.

You might want to order syringes (<.4mm). Or you can maybe cut a wire from a wire brush. Or from an electronics wire. Then heat the nozzle to 180C and stick the wire inside. This doesn't usually work as the clog just comes back in again.

Another technique:

1) Heat head to 180C.

2) Extract the filament completely.

3) Loosen the 4 finger screws holding the head together 3 or 4 turns.

4) remove the clip that holds the bowden. (blue clip? or red?)

5) Push down on the ring that the clip held up and while pushing down, pull up on the bowden tube.

method A:

a1) Insert a 200mm length of PLA.

a2) set tem to 90C. Wait 5 minutes for it to cool.

a3) When temp has been 90C for a whole minute, pull hard on the PLA. HOpefully the clog will come out.

a4) heat back to 180C. Put fresh piece of PLA in and see if it comes out the nozzle.

a5) If still clogged go to step a1

method B:

Take the head completely apart, stick a paper clip into the *top* of the print head while at 180C. scrape around and dig out all PLA and other gunk.

0g1IYVE.jpg

 

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Thank you gr5 your picture was of great value.

Ok i figure it out how to unmount it and clean it. Now it is printing.

Could be useful to add a special section on the manual.

Furthermore i would like to suggest an implementation of 2 things in the next firmware update:

1) Like the home position for the extruder, a menù that take the centered position to be able to unmount the head easily without moving manually the head.

2) Some kind of unblocking status where the t° is raised to at least 220° (and you do not have to do it manually) and you can easely move the filaments up and down with the control.

 

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My UM2 nozzle blocks constantly, it's my biggest complaint with the printer. To get around it I keep a wire BBQ brush handy, and pull single bristles out of it when I need to clear the nozzle.

When I start each print, I increase the heat to 260 degrees, then, while it's getting ready to print, I poke the wire inside the nozzle.

When the print begins, it is almost always partially blocked, and under extruding. I keep the temp at 260, and always print with "brim" by the time the head has done it's 3rd brim outline, the head is extruding properly, and I reduce the temp back to 220.

 

 

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Braddock - are you sure that the nozzle is 'blocked' at the start of your prints. It's fairly normal to have under extrusion at the start of a print because the nozzle can tend to ooze during the start-up period, or during cool-down, so there's often not enough plastic in the print head at first.

Indeed, one of the reasons to print with a skirt or brim is to get plenty of 'pre-print' extrusion to ensure that the head is fully primed by the time you start the actual object.

 

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2) Some kind of unblocking status where the t° is raised to at least 220° (and you do not have to do it manually) and you can easely move the filaments up and down with the control.

 

Doesn't this already exist in the advanced menu? I will go check later.

 

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Now i have a strange behavior: The bowden tube does not remains in his position! It raise itself outside of the "white tube" The red clips does not do anything..

Right position: https://plus.google.com/116867274133488266077/posts/PsXVpQKSqNv

Wrong position after some minutes of printing:

https://plus.google.com/116867274133488266077/posts/TsrAEwrbi6x

How can i solve this?

 

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Braddock - are you sure that the nozzle is 'blocked' at the start of your prints. It's fairly normal to have under extrusion at the start of a print because the nozzle can tend to ooze during the start-up period, or during cool-down, so there's often not enough plastic in the print head at first.

Indeed, one of the reasons to print with a skirt or brim is to get plenty of 'pre-print' extrusion to ensure that the head is fully primed by the time you start the actual object.

 

That may be the case sometimes, but other instances, the feeder is jumping back, trying to feed filament that isn't being extruded. Another strange thing is, I had previously been able to print at temps as low as 190 - 200 but this seems to cause problems with my recent prints. I've only used the PLA from Ultimaker.

 

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Now i have a strange behavior: The bowden tube does not remains in his position! It raise itself outside of the "white tube" The red clips does not do anything..

Right position: https://plus.google.com/116867274133488266077/posts/PsXVpQKSqNv

Wrong position after some minutes of printing:

https://plus.google.com/116867274133488266077/posts/TsrAEwrbi6x

How can i solve this?

 

I don't think my bowden tube has ever gone all the way down to the white part at the base of the spring, mine is permanently at the position in your "wrong position" pic.

 

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Just like with the Ultimaker Original, it is of importance that the bowden tube stays at its place.

If it doesn't stay at its place anymore after you have done a repair of some kind, you either didn't put it back together properly or you damaged something while taking it apart.

Can you upload a picture of your entire print head assembly?

When you have fully inserted the bowden tube so it reaches all the way until the teflon tube, can you manually lift it up?

If you can, either you scraped the outer surface of the tube with the clip. Now it is thinner, the clip can't hold it anymore.

Or the teeth of the clip are bent, and now they can not apply enough force to hold the tube.

You can test this by putting the bowden tube in backwards. (feeding the filament in may be a little bit trickier because in the normal way, the opening is a bit wider on the back end). If you have swapped the tube and it can not move anymore, the bowden tube was scraped. We could send you a new bowden tube so you don't have to leave it like that.

If it still possible to manually pull it up, I think the clip is bend. You can take out the clip and take a look inside.

Looking forward to hear about your findings,

 

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The bowden tube positioned himselw how i former showed you, that's why i had to unmount the head and make things in the right position.

By now it's 3 time i do this job. I really did not damage anything...because there is nothing to damage... the clip seems ok (the same dimensions of the one behind) the tube seems a simple tube.. and the grey part (the one that hold the tube) seems ok but maybe it's his fault that the tube is loose... So what i have to do?

Now it's everytime i start a print. At the first retraction it brings back the tube outside of the white teflon part.

But the tube do not seems scraped or else and once fixed, manually do not seems to be loose. But is not.

 

Just like with the Ultimaker Original, it is of importance that the bowden tube stays at its place.

If it doesn't stay at its place anymore after you have done a repair of some kind, you either didn't put it back together properly or you damaged something while taking it apart.

Can you upload a picture of your entire print head assembly?

When you have fully inserted the bowden tube so it reaches all the way until the teflon tube, can you manually lift it up?

If you can, either you scraped the outer surface of the tube with the clip. Now it is thinner, the clip can't hold it anymore.

Or the teeth of the clip are bent, and now they can not apply enough force to hold the tube.

You can test this by putting the bowden tube in backwards. (feeding the filament in may be a little bit trickier because in the normal way, the opening is a bit wider on the back end). If you have swapped the tube and it can not move anymore, the bowden tube was scraped. We could send you a new bowden tube so you don't have to leave it like that.

If it still possible to manually pull it up, I think the clip is bend. You can take out the clip and take a look inside.

Looking forward to hear about your findings,

 

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and the grey part (the one that hold the tube) seems ok but maybe it's his fault that the tube is loose

 

Did you look inside this gray part? Can you see the blades? Either this part is bad or the bowden tube is scraped slightly. It's difficult to see visually. You could check maybe with calipers. Personally I would ask UM support to replace both parts and while waiting I would cut 10mm off the end of the bowden and hope that's enough. These parts do not cost much money so get them replaced before your warranty runs out.

Another thought:

Try loosening the 4 thumb screws 5 or 10 full turns. Then push the bowden all the way down. Then tighten the 4 thumb screws. See if this helps. If it's not enough, maybe 20 full turns?

 

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On top of the print head there is a little red clip. That clip holds up something which is part of a larger (but still small) part. *that* part - I don't know what it is called. Let's call it the "bowden holder".

The "Bowden holder" works such that you have to push down on the outer ring of the bowden holder to remove the bowden. When you push down on the bowden holder it retracts (sucks in) 4 tiny metal blades.

After you remove the bowden tube you can look down into the "bowden holder" and possibly see the blades. Those blades dig into the bowden to get their grip - to "hold the bowden".

It's easy to break one or more of those blades. Either bend the blades backwards or they can fall out.

Also it's easy to scrape the bowden tube so that it is now smaller diameter. This scraping is almost invisible.

 

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