Jump to content
Ultimaker Community of 3D Printing Experts
reject

Why it clogs? teflon coupler?

Recommended Posts

Hi people,

Im having a lot of problems with my UM2, it started 1 month ago, now its impossible to make a single piece. I checked a lot of threads and used your advises but now im just lost, nothing worked.

 

The print start normally, but passed 2 o 3 min, it starts to and the filament clogs. When i pull the filament after this, there are always a ball bigger than the tube.

I did the atomic method, and the filament is always damaged, no matter the times i do ( last time i did like 10 times and the result after 4-5 was the same).

I used a 0,3mm hypoalergenic needle to clean the nozzle, but nothing changed.

I tried to eliminate the tension on the feeder using just 1m of filament, but the tension is not here.

I thing my teflon coupler is the responsible of this,

Normal pull + 3 atomic method

Teflon coupler

Teflon coupler

Teflon coupler

Normal pull

atomic method 1 month ago

 

sorry for my english :(

Any ideas?

 

Share this post


Link to post
Share on other sites

Is the fan at the back of the print head running? It should turn on as soon as you turn on the printer.

It also looks like your bowden tube is not pushed down all the way into the teflon piece and held in place there. When you re-assemble, make sure that you push the bowden tube all the way into the teflon, then pull the white collet up as far as it will go while pushing the bowden tube down, finally put the red horse shoe clamp back. Now try to move the bowden tube up and down, it shouldn't move.

If that doesn't work you can try to unscrew the four long bolts a couple of turns, repeat the steps above and then tighten the screws.

 

Share this post


Link to post
Share on other sites

Try robert's suggestsions first.

Especially the 3rd fan!

I wish you showed a photo of the *other* side of the white teflon part. It's the other side that tends to go bad - the hot side. Also try pushing some virgin filament through the coupling to feel if there is friction. If so you might want to drill it out (3mm drill bit).

But I'm thinking your 3rd fan broke. The wiring breaks easily - especially under the black mesh covering just at the top of the print head.

 

Share this post


Link to post
Share on other sites

Thank you lRobertl & gr5.

The 3rd fan is ok, it works fine as always. Also, i always put the bowden tube with your screw method IRobertI, if i dont do this, it only prints like 20 seconds.

gr5 your idea of making a 3mm drill was my next move, the teflon part is, as you said, a bit deformed on the heated side, i cant even pull it out. Pushing some virging filament feels with a hell of friction, thats the reason i blamed the teflon.

Teflon coupler

I will try the drill next, lets see what happens. Thank you!

 

Share this post


Link to post
Share on other sites

If the deformed teflon problem comes up again. You might want to contact support, we actually have fiberglass filled teflon now, which doesn't deform as easy as the normal teflon that we used before.

 

Share this post


Link to post
Share on other sites

These new Teflons are available as spare parts? I guess it will eventually happen to all of us who use the old teflon (or are they damaged because of a bad use of the printer??)

I would be interested in ordering one to prevent delay from a "broken" printer

 

Share this post


Link to post
Share on other sites

These new Teflons are available as spare parts? I guess it will eventually happen to all of us who use the old teflon (or are they damaged because of a bad use of the printer??)

I would be interested in ordering one to prevent delay from a "broken" printer

 

Pretty sure support could hook you up with those parts.

Note that the price of spare parts, and getting them into the shop is something that's being worked on. (see the other topic about that)

 

Share this post


Link to post
Share on other sites

The teflon does better if you keep the temperature lower and don't tighten the nozzle too high up (the nozzle position is adjustable so that you can make both nozzles the same height easily - if dual extrusion ever becomes available). I'm not sure which is more important, having the nozzle down low or keeping the temperature low. I think 250C is a bit hot for that part so keeping your printing at 220C might improve the teflon piece lifetime. Or maybe failure is inevitable.

 

Share this post


Link to post
Share on other sites

The teflon does better if you keep the temperature lower and don't tighten the nozzle too high up (the nozzle position is adjustable so that you can make both nozzles the same height easily - if dual extrusion ever becomes available). I'm not sure which is more important, having the nozzle down low or keeping the temperature low. I think 250C is a bit hot for that part so keeping your printing at 220C might improve the teflon piece lifetime. Or maybe failure is inevitable.

 

So printing with ABS or Colorfabb XT (temp of 250°c) will for sure damage the Teflon...

I had and odd thing last week, the filament was stuck in the teflon (i think). It had been retracted from the previous print and the next day nothing was extruded.

So i tried removing the filament and it didn't move. I removed the bowden tube and then the filament came out... should i be worried??

 

Share this post


Link to post
Share on other sites

Maximum permanent temperature for PTFE is around 250°C, peaks are allowed up to 280°C. These are the numbers which can be found at various sources.

 

To bad (for us) that those maximum working temperatures do not account for deformation under stress as we found out (the bad way)

 

Share this post


Link to post
Share on other sites

So i think my Teflon is deformed too. I didn't dismantle it as i have an event saturday where i bring my UM2 with me.

It's been a couple of days i've been noticing some little underextrusion mainly when retraction is on. If i disable retraction all seems to be okay (i print at 40mm/s most of the time).

So yesterday i printed a small skull of a horse that i scanned.

0.1mm layers, 30mm/s, temp at 220°c

This was the result:

20140724 054559

It doesn't show on the pics a lot but there are a lot of small holes in the print due to small underextrusion. So i disabled retraction and the rest of the print was okay.

After that i did the cylinder test that my UM2 passed succesfully a couple of weeks ago (even the tougher test gave me good results).

20140724 054529

 

Attempts are from left to right.

 

It fails at 7mm3/s i know it isn't that bad but for me it's a concern because it worked perfectly before.

 

After first attempt i atomic bombed my nozzle twice. Nozzle seems clear of residue. But when i push it by hand i feel a resistance.

 

Second attempt failed quite as bad as first attempt.

 

The i removed the printed clip i have for the bowden tube because it's one of the thing i changed and put the stock clip back on.

 

Third attempt was even worse.

 

What do you guys think? Teflon or not?

 

The behaviour during retractions is a big warning for this or am i wrong?

 

Share this post


Link to post
Share on other sites

To bad (for us) that those maximum working temperatures do not account for deformation under stress as we found out (the bad way)

I have been following this thread for some time and realise my problems are because of deformation in the teflon coupler. I have done some printing with ColorFab XT and now realise that problems started after than, I plan to disassemble the head later today. I have been in contact also with support to buy replacement parts, bowden tube ,coupler and print head.

Daid I assume that any new shipments of parts will be with the new teflon coupler ?

Stu

 

Share this post


Link to post
Share on other sites

Hello everybody,

Thank you for your help here. I have the same issues describe and they begun after printing with colorfab XT.

My teflon coupler is deformed at the tip, and I have ordered a new one, but I am stoped with the printing, could I cut the teflon coupler a bit, to get rid of the deformed part and use it while waiting, will it work?

Thank you

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Announcements

  • Our picks

    • Architect Contest | Entourage 01.
      Presenting an idea, an architectural design or something as big as an urban project isn't easy. A scaled models can really help to get your idea across. But besides your main model, there is more needed to get your idea across vividly! An architect regularly uses various entourage sets to help bring these ideas and models to live. 
        • Like
      • 9 replies
    • What The DfAM?
      I'm Steve Cox, an experienced engineer familiar with 3D printing. I wanted to share some DfAM guidelines with this community to help and make stronger parts.
      I'm also an Autodesk Certified Instructor for Fusion 360, so many of the images in ...
        • Thanks
        • Like
      • 17 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!