Teflon spacer replacement

[cleven 4]

Here is the feeder

https://www.youmagine.com/designs/alternative-um2-feeder-version-two

I redesigned mine slightly for my needs but the original works just as well.

[flashp0int 0]

Ultimaker support sent me a new spacer, very efficient customer support! I will buy ESC fans and try to increase airflow and also reduce spring pressure. Thanks for the suggestions!

 

How do you contact UM2 support ?

I have tickets open there since over a week with no answers.

 

[cleven 4]

You can even get a hold of them on the forums. What severity level did you se on your ticket? I did a ticket once they replied within a week or so. You can always call by phone too. They have answered any time it have called.

 

How do you contact UM2 support ?

I have tickets open there since over a week with no answers.

 

[densohax 0]

260c... Maxed out. You are reducing friction with heat, yes but there are other material issues!. This temperature is where the ptfe will start to break down. This may make things worse over time.

I'd order a new one and then

Since you cut it. Maybe Try re drilling out the hole slightly making sure it is clean inside and all edges are smooth. Slide the filament before and after, you should notice a drastic improvement with friction.

Also

Have you modified the feeder yet?

Print Irobertls feeder it allows you to Better adjust the pressure on the filament. Make sure you make all the parts where the filament can touch smooth. also ensure your Bowden tube is secure and not moving with the retraction.

 

Yep I have Robert's feeder. It's one of the first thing I've done. My ABS filament roll is also on the floor in straight line with the feeder input. So there's no friction there. I know when a problem occur, because I see that the feeder gear will get ABS dust on it, but that only happened before my modification. The feeder stepper no longer skip backs now.

I didn't drill out the spacers, but they don't seem to have that much friction, I can slide the filament in them and extrusion is easy. I may drill them out if I sense they are causing too much problem over time!

I certainly don't like extruding at 260.. With my TOM I was extruding at 225-230 and never had problems..

I am beginning to wonder if my real problem is the thermocouple, maybe it is reporting a higher temperature?

My problem seems to be that during retraction, the filament comes back in the spacer and in fact it stretches instead of being pulled up. So there's a little plastic left in the tip, when the filament pushes back after retraction, that's when I have problems (at 240). Like if the filament wasn't able to heat back instantly to melt. There's a delay there that will cause heavy under extrusion for some time. The only thing I can think of, is insufficient temperature at this point.. Unless I am misunderstanding the issue...

I feel that at 240 it should be more than enough to print ABS, but at 260 there's a BIG improvement in quality and layer bonding!

 

[cleven 4]

Also not having a spring can cause issues. The material wants to slightly expand when heated. If it doesn't have space to expand linearly it could possibly effect the diametrical clearance. It is small amounts but could have an effect

[densohax 0]

Also not having a spring can cause issues. The material wants to slightly expand when heated. If it doesn't have space to expand linearly it could possibly effect the diametrical clearance. It is small amounts but could have an effect

 

Good point!

Then I may have to drill the PTFE a little as a buffer.. I will also diminish the temperature a little and put a 5 cfm fan as a replacement.

[3poro 9]

I will also diminish the temperature a little and put a 5 cfm fan as a replacement.

 

Please check the today's posts on this thread: http://umforum.ultimaker.com/index.php?/topic/6307-um2-twin-tornadoes/

Maybe you'll not face the same side effect as I did, but just in case - you probably need to control the temperature readings after installing more powerful fan(s) to make sure there are no surprises. I'm lucky I caught the issue so quickly - I can imagine myself hunting down such a problem for days (and nights)...

 

[densohax 0]

Please check the today's posts on this thread: http://umforum.ultimaker.com/index.php?/topic/6307-um2-twin-tornadoes/

Maybe you'll not face the same side effect as I did, but just in case - you probably need to control the temperature readings after installing more powerful fan(s) to make sure there are no surprises. I'm lucky I caught the issue so quickly - I can imagine myself hunting down such a problem for days (and nights)...

 

Thanks for the heads-up!

I was reading your thread actually and was wondering how much you could draw from the power on the fan..

Looks like the ADC is quite sensitive to noise, maybe we need some shielding as well in the wiring?

The side fans are PWM driven? If so, maybe they are the cause of the misreading of the ADC? I had the fans to 100% with PLA but with ABS I am between 20 and 50% .. Maybe this could be a problem...

Btw, I'm quite sure my temperature is off as well, I will certainly try to modify the firmware eventually to get more accuracy out of the temperature sensor.

 

[flashp0int 0]

You can even get a hold of them on the forums. What severity level did you se on your ticket? I did a ticket once they replied within a week or so. You can always call by phone too. They have answered any time it have called.

 

 

Ok, then there might still be hope. It is about a week ago.

I am not used to so long delays. in my business, we have 4 to 24 hours SLAs based on what type of device. So a week seemed very long to me. Thanks.

 

[cleven 4]

Yeah. I think it is luck if they are busy or not. Small company normal people doing their best .

 

Ok, then there might still be hope. It is about a week ago.

 

I am not used to so long delays. in my business, we have 4 to 24 hours SLAs based on what type of device. So a week seemed very long to me. Thanks.

 

[cleven 4]

Update!

The final and best resulting tests were using these specifications below. Each of the variations went through approx10hrs of printing where I was randomly testing the extrusion rate. (I was printing some large objects for work)

After each variation and test I cleaned out the nozzle by removing all material inside. This was done by heating the nozzle to 210c, pushing in a small section of filament until there was extrusion. Then allowing the nozzle to cool and pulling on the filament when it reached 90c.This ensured a clean start for each test.

The round at the bottom can be ignored, but remove any burrs present by slightly breaking/smoothing the edge. The chamfer at the top greatly assisted in material insertion. Without the chamfer it became annoying during the material changes at times. The main OD is around 11mm but does not matter as long as it is larger than the OD of the spring.

 

[davinci 0]

Hi...!

I have the same problem with my new UM1 (bought end of June 2014)

After several PLA tests, printed at high Quality about layerhight 0.06mm and a printing speed of 12 - max 20 mm/s and temperatur between 190C and 205C, full retracting settings ...

With these settings I printed about 200 h or more, with good results. (At this point: very brave Ultimaker!!) Suddenly there was underextrusion and I realised jamming...

After several check ups what really happend (all things looked good, I thought), I noticed at least an inner "bulge" in the teflonspacer that hollows the teflon thing spherical near it's bottom (just close to the brass, that fits into the PEEK)

There wasn't any leak, or gap in the PTFE/ PEEK/ brass - system(!), no melted material pushed out, just this little "bulge", that made the trouble...!

The teflonspacer seems to get very soft and weak (after 200h?!) and if the temperatur isn't so much high, the plastic forms a "champagne-cork-like" plug (under the pressure of extrusion), not getting melted at all, block the flow of filament ....and the nozzle won't get any new material.

also see from "Kris" (thx Kris!): http://umforum.ultimaker.com/index.php?/topic/5953-idea-on-underextrusion/

I also think, that one of the problems are the "gaps" between the PTFE bushing and PEEK during high temperatur leads to filling the gaps with melted plastic...

SO WHAT I can do? ... every 200 printing hours buying a new PTFE Spacer about 20,-EUR wouldn't solve the problem!

@MartijnvG , the ULTISTRUDEL TEST BENCH and Daid :

Is it right, that Ultimaker provides some glass fiber reinforced teflon spacers? Just for the UM2, or also for UM1?

Have I already got a glass fiber PTFE - thing in my new UM1? (if not, I will try this new one immediately!)

I think it's important, that the fitting of the PTFE to the PEEK/ brass is very close! It only happens with the "contact pressure" of the wooden printhead-housing and the bowden (on UM2 the metal spring ensures therefore?!)

The material has to be elastic, to make an hermetic sealing ... (like Teflon...?!)

SO what about SCREWING in the PEEK tightly, with a "thread cutting" ..?

Tightly srewing means, that you can replace it with a stronger material, less weakly than PTFE, e.g reinforced glassfiber/ carbonfiber PEEK -bushing ...?! Is Friction really such a big problem?

And thx to 'Cleven', you made a good work...

.. best greetings!

 

 

[densohax 0]

Tightly srewing means, that you can replace it with a stronger material, less weakly than PTFE, e.g reinforced glassfiber/ carbonfiber PEEK -bushing ...?! Is Friction really such a big problem?

 

Yes friction is one problem. I did try ninja flex with my redntubing and it did not work.. So I drilled the red ptfe as Cleven suggested and it helped a lot!!

I will try to put a ceramic sleeve between the tubing and the hot end, I am unsure if it is a good idea yet, but my modification seems to work right now, we'll see for how long.

Also, for the record, I had 110 hours on my printer before failure of the teflon part. and it did exactly as you explained!

[donmilne 2]

@Cleven, I'm not quite following this thread. Can you please expand on what important changes you have made to the spacer, what problem you think this addresses, and why?

 

[cleven 4]

The modifications tested were on ID, OD, length, chamfers, rounds etc. Slightly modifying each individually to reduce friction and wear within the PTFE part. I have also tested other materials such as higher ptfe, peek and torlon. I have tested each of the verifications with the 10mm3/s flowrate and found that the last posting of sizes worked best to achieve this higher flow rate.

@Cleven, I'm not quite following this thread. Can you please expand on what important changes you have made to the spacer, what problem you think this addresses, and why?

[donmilne 2]

Thanks.

 

[densohax 0]

Please check the today's posts on this thread: http://umforum.ultimaker.com/index.php?/topic/6307-um2-twin-tornadoes/

Maybe you'll not face the same side effect as I did, but just in case - you probably need to control the temperature readings after installing more powerful fan(s) to make sure there are no surprises. I'm lucky I caught the issue so quickly - I can imagine myself hunting down such a problem for days (and nights)...

 

Just installed one tornado fan! WOW SO LOUD!! I can't live with that! XD

However, they are pushing quite a lot for their size!

Did you silenced them a little? My ears are bleeding as I type this!

Looks like the rods are resonating with the fan, amplifying the noise..

 

[3poro 9]

Just installed one tornado fan! WOW SO LOUD!! I can't live with that! XD

However, they are pushing quite a lot for their size!

Did you silenced them a little? My ears are bleeding as I type this!

Looks like the rods are resonating with the fan, amplifying the noise..

 

LIKE I WROTE IN MY ORIGINAL MESSAGE: "IF I WOULDN'T HAVE THE DOME AROUND MY PRINTER, THE NOISE FROM THE NEW FANS WOULD DRIVE ME NUTS."

 

YOU CAN TRY TO REDUCE THEIR VOLTAGE BY 10% OR 20%.

 

I HAVE 2 OF THE TORNADO FANS, SO I NEED TO SHOUT TO HEAR MY OWN VOICE

 

[solid-print-3d 30]

for what it's worth, I posted a thread on what NOT to do (at least without an ultimate cooling solution)

http://umforum.ultimaker.com/index.php?/topic/7247-um2-aluminum-insulator-what-not-to-do/

 

[yzorg 9]

Hi guys

have to report another UM2 blocked.

i couldnt find the source of my very severe underextrusion problem.. until i disassembled everything..

Im not shure but i think i already had a glass-infused spacer..

 

I noticed a relatively strong notch inside my Teflon spacer. On its exit-side to the nozzle, it has got a quite strong ridge all around.

the teflon is still completely white. no burned plastic residue anywhere.

Filament "can" still go though the spacer but also most of the times blocks up instantly. To me it looks like, the spacer is made from too soft material.. i think could crush it by hand. i feel like PLA is harder than that spacer = can damage it.

since i cannot photograph my spacer good enough, a drawing should help a bit:

i order some replacements.. but i already know it wont last.

I hope someone comes up with a better solution for this.

 

[3poro 9]

have to report another UM2 blocked.

i couldnt find the source of my very severe underextrusion problem.. until i disassembled everything..

Im not shure but i think i already had a glass-infused spacer..

 

I noticed a relatively strong notch inside my Teflon spacer. On its exit-side to the nozzle, it has got a quite strong ridge all around.

the teflon is still completely white. no burned plastic residue anywhere.

[...]

i order some replacements.. but i already know it wont last.

I hope someone comes up with a better solution for this.

 

Here's my 2nd PTFE isolator, the new glass-infused type:

 

...after some weeks of use. Can anyone quote a price for 10pcs?

 

[cleven 4]

Wow, what the heck did you do?! lol, Very strange wear....

How hot are you running? Remember it starts to break down around 250 so it isnt the greatest around there.

 

[densohax 0]

Here's my 2nd PTFE isolator, the new glass-infused type:

 

 

...after some weeks of use. Can anyone quote a price for 10pcs?

 

Again, that's EXACTLY what happened to my spacer! The ridge inside, at the same exact place!

 

[densohax 0]

LIKE I WROTE IN MY ORIGINAL MESSAGE: "IF I WOULDN'T HAVE THE DOME AROUND MY PRINTER, THE NOISE FROM THE NEW FANS WOULD DRIVE ME NUTS."

 

YOU CAN TRY TO REDUCE THEIR VOLTAGE BY 10% OR 20%.

 

I HAVE 2 OF THE TORNADO FANS, SO I NEED TO SHOUT TO HEAR MY OWN VOICE

 

I went back to the original fan, it was taking a LOT longer to heat the head and the temperature was oscillating quite a lot.. It would need some calibration to keep that fan, or an enclosed box.

 

[eldrick 65]

If you are printing at 260C, then the spikes before PID settles down are surely above 265C, the temperature at which PTFE breaks down - even at temps near that, it turns brown and loses structural integrity, as you have demonstrated.

The solution is don't print over 245C if you want the spacer to last. Check the vendors printing temp recommendations - I'd be very surprised if 260C is suggested.