Atomic cleaning & the teflon ring?

[valcrow 145]

Hey Guys,

So I did a few Atomic pulls and they've come out really clean for the most part. However there is still a decent amount of friction in the nozzle and now I'm getting underextrusion. (on the UM2.)

I'm pretty sure it's due material buildup between the teflon ring but I'm not entirely sure what I should do to clean that out?

There was this one time where an atomic pull yanked out a burnt looking disk and it worked really well after that.

Any tips you guys have for cleaning out that ring without disassembling a lot of stuff?

 

[DidierKlein 729]

It's quite easy to take the teflon out, it doesn't take that much time

Check out this video for the steps to follow:

 

I had a similar build up of burned material at the bottom of my teflon i cleaned it with a cutter, you can also take that opportunity to check if there's friction inside (pass a piece of filament and see if you feel any friction).

If yes you can drill it out a bit

 

[valcrow 145]

Thanks for the videoI followed your guide, took it apart, it didn't 'seem' like there was anything wrong with it... not much gunk between the brass and the teflon like I thought.

But there was more friction on the teflon than I expected so i used a small cylindrical file and really lightly enlarged the bottom part a tiny bit. I put it together and its printing better now.

So I guess it's solved for now! will update if problems persist.

 

[valcrow 145]

K so it's still under extruding :/ but not as badly

 

[korneel 176]

Valcrow;

how many hours have you put on your printer and have you ever replaced the PTFE coupler?

i'm pretty sure when you open it up, you'll see a little "dimple" in the bottom inside of the PTFE coupler. that is causing your retraction issues.. time to replace.

 

[valcrow 145]

Valcrow;

how many hours have you put on your printer and have you ever replaced the PTFE coupler?

i'm pretty sure when you open it up, you'll see a little "dimple" in the bottom inside of the PTFE coupler. that is causing your retraction issues.. time to replace.

 

~540 hrs printing time. around 500m of filament.

I have no idea if that's a lot or not. Been working relatively perfectly until now.

Most people have suggested it's the Teflon piece being the culprit. Guess I'll have to find a new one.

 

[korneel 176]

yeah, 500 hours is a lot in my opinion.. mostly PLA right?

I've been searching for guidance on when to replace it and i've had to replace PTFE couplers with as little as 300 hours on them and already deformation.. the problem is the pressure on the PTFE coupler with the temperature, and you can see the bottem of the coupler is a bit flattened and there is a dimple. check the PTFE coupler replacement topic and you can see how it should look

 

[tinydancer 0]

That was my problem Valcrow, as I have around the same amount of hours that you have. The PTFE was pretty worn when I removed it and the nozzle has some buildup inside that never came clean even after at least a dozen atomic pulls. Replaced PTFE and nozzle and it's now running so far like it did when I took it out of the box. And I've only used it for PLA.

Personally I think the printer should come with a couple of replacement PTFE couplers and an extra nozzle. Especially when you can only go through the Netherlands for replacement parts at this time.

 

[eldrick 65]

I don't understand why people keep griping that the plastic collet overheats and degrades, but no-one seems to do have done anything about it, aside from costly replacement.

Look at this thread - it works!

http://umforum.ultimaker.com/index.php?/topic/6084-um2-bowden-block-cooling-improvement/

I've got over 2000 hours printing mostly ABS, and the collet has not gone downhill at all, because I took 15 minutes to improve the cooling of it. If you use all of the always-on-fan output, instead letting half of it be wasted, the collet lasts apparently forever, and since there is no dual-extruder option for a UM2, nothing is lost.

 

[tinydancer 0]

I don't understand why people keep griping that the plastic collet overheats and degrades, but no-one seems to do have done anything about it, aside from costly replacement.

Look at this thread - it works!

http://umforum.ultimaker.com/index.php?/topic/6084-um2-bowden-block-cooling-improvement/

I've got over 2000 hours printing mostly ABS, and the collet has not gone downhill at all, because I took 15 minutes to improve the cooling of it. If you use all of the always-on-fan output, instead letting half of it be wasted, the collet lasts apparently forever, and since there is no dual-extruder option for a UM2, nothing is lost.

 

Have you had to do anything to the PTFE coupler like drilling it out occasionally? I might have to give this a try.

 

[eldrick 65]

Nope - I haven't touched it since early 2014, when the newer fibreglas-filled version was made available.

I'll take a look at it again when I install the Flex3drive in a couple of weeks, but it's been printing fine.

 

[ultibrain 5]

A small remark about the video. I used blue tape to hold the black parts together. This saves some disassemble/assemble time.

 

[tinydancer 0]

Nope - I haven't touched it since early 2014, when the newer fibreglas-filled version was made available.

I'll take a look at it again when I install the Flex3drive in a couple of weeks, but it's been printing fine.

Good to know. My PTFE showed a lot of wear after 500+ hours, and that was just printing PLA/PHA from Colorfabb.