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Teflon spacer replacement


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Posted · Teflon spacer replacement

About the material getting to hot and plugging during lots of retractions. i have been actively cooling the hot-ends with a 35mm fan and fan duct on the front as well. The combination should reduce the overall heat in the hot-end and prevent that from happening.

 

 

Can you expand on this problem and your solution?

 

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    Posted · Teflon spacer replacement

    Can you expand on this problem and your solution?

     

    i will when i have some more data and results. the tests are running now so i would like to give more information when i can tell you guys a little more with some actual data in stead of just guesses.

     

    why do not use a ceramic thermal coupler?

    below is the datasheet of a industrial ceramic coupler:

    http://www.omega.com/Temperature/pdf/PTRA_PTRM.pdf

     

    We have tried a number of ceramics but the things wh have tried seemed not to work because the PLA would stick to it like glue when molten. The trouble is the amount of pressure we can apply on the filament before it deforms/grinds. so we need the PTFE for the low friction. but with the added heat i'm afraid deformation might occur sooner.

    But as i said, tests are running now and i hope by the end of next week i might know some more :)

     

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    Posted · Teflon spacer replacement

    Wow! That looks very interesting!

    Was it difficult to machine? (Our workshop did not like what they read about machining it as I mentioned before)

    Did you try printing anything with lots of retraction yet?

    I am very curious how Duratron handles hot plastic since one of it's recommended uses is for components for injection molding machines.

    That means it could be the perfect material for the thermal insulator, if the friction with molten PLA is reasonably low.

    If Duraton seems to work, I would switch focus back to that since Kalrez seems very difficult to get and since Duratron is no more expensive than Vespel.

     

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    Posted · Teflon spacer replacement

    Wow! That looks very interesting!

    Was it difficult to machine? (Our workshop did not like what they read about machining it as I mentioned before)

    Did you try printing anything with lots of retraction yet?

    I am very curious how Duratron handles hot plastic since one of it's recommended uses is for components for injection molding machines.

    That means it could be the perfect material for the thermal insulator, if the friction with molten PLA is reasonably low.

    If Duraton seems to work, I would switch focus back to that since Kalrez seems very difficult to get and since Duratron is no more expensive than Vespel.

     

    hi

    It is not easy to machine because the material retracts easily.

    I tested successfully with pla and xt-color. but I have to do more tests.

    Tomorrow i test nylon and abs with more temperature.

    I keep you informed .... I have to sleep. :wink:

     

     

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    Posted · Teflon spacer replacement

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

     

     

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

     

    so i'm going to quote quite the old topic;

    (crosspost from http://umforum.ultimaker.com/index.php?/topic/8263-wanneer-is-een-pfte-element-nu-versleten/ )

    Teflon element 1:

    PFTE 1

    PFTE 1 1

    PFTE 1 2

    as you can see, i also have the indentation as scirbbled below the third picture

    there is also some XT stuck in it.

    PFTE 3

    here you can see the indentation as well

    PFTE 2

    and here as well even worse.

     

    the thing is, none of these have been used over 250 hours. i have also not printed with these over 240 degrees...

     

    so the question is, are they actually deformed or should i still be able to use them?

    i believe they are still 3MM inside, but is there something i can do to keep using them? perhaps drill them out at 3.2 mm?

    or can i just use them as is?

     

    or is it better to cut my losses?

     

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    Posted · Teflon spacer replacement

    so i'm going to quote quite the old topic;

     

    Why, we all know what happens with the spacer.

    You should replace it with better material.

     

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    Posted · Teflon spacer replacement

    hi guys

    i've been quite for a little while because my focus got slightly shifted to another project. (to much to do, not enough people to do it). i'm finishing up this project and i hope to get my focus back on the ring as soon as i can.

    so no extra results yet. but just letting you know i haven't forgotten :)

    cheers

     

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    Posted · Teflon spacer replacement

    MartijnvG;

    3Poro has been kind enough to offer me a Vespel Washer which i have installed in my machine. by now i have run another roll of PLA and XT through it. I also live very close to Geldermalsen and i have some other interesting materials such as cleaning filament. if you want I can come by the office tomorrow with my Ultimaker 2, and you can have a look at the Vespel Washer...

     

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    Posted · Teflon spacer replacement

    MartijnvG;

    3Poro has been kind enough to offer me a Vespel Washer which i have installed in my machine. by now i have run another roll of PLA and XT through it. I also live very close to Geldermalsen and i have some other interesting materials such as cleaning filament. if you want I can come by the office tomorrow with my Ultimaker 2, and you can have a look at the Vespel Washer...

     

    Hi Korneel,

    i think it's a good idea that you swing by and show me the spacer 3poro has made. Today is my day off :D and i think i would like to get some more info on the subject myself before talking to you. so i'll make a schedule and i'll contact you with a date so we can have a good talk.

    is that ok with you?

     

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    Posted · Teflon spacer replacement

    sure! i work from home so i'm pretty flexible. send me a PM and we'll work it out.

     

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    Posted · Teflon spacer replacement

    I keep you informed .... I have to sleep. :wink:

     

    glloq - any updates?

    So far, my experiences with Vespel washer have been very good. Having said that, I did have to drill it a bit to make its inner diameter match the diameter of my Teflon isolator. Ultimaker's translucent PLA (green) caused me headache. First, it's very tightly wound to its reel, so the feeder had trouble fetching it. I had to unwind the filament to another reel (and back) in order to lower the burder on the feeder.

    Then, there were extrusion problems - I believe the threshold (3.3mm->3.1mm in my case) between PTFE isolator and Vespel washer was to blame.

    I was thinking about making an isolator purely out of Vespel, but I'm concerned about friction. If Duratron doesn't have problems with friction, maybe Vespel would be OK as well...

     

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    Posted · Teflon spacer replacement

    glloq - any updates?

    So far, my experiences with Vespel washer have been very good. Having said that, I did have to drill it a bit to make its inner diameter match the diameter of my Teflon isolator. Ultimaker's translucent PLA (green) caused me headache. First, it's very tightly wound to its reel, so the feeder had trouble fetching it. I had to unwind the filament to another reel (and back) in order to lower the burder on the feeder.

    Then, there were extrusion problems - I believe the threshold (3.3mm->3.1mm in my case) between PTFE isolator and Vespel washer was to blame.

    I was thinking about making an isolator purely out of Vespel, but I'm concerned about friction. If Duratron doesn't have problems with friction, maybe Vespel would be OK as well...

     

    So i will start measuring the friction of the new parts and the vespel ring hopefully this week. we also have some parts made in duratron and other materials.

    i will check if i can post my results on the tests here in the forum :) lets see what the tests reveal.

     

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    Posted · Teflon spacer replacement

    just to add to the approach 3Poro has taken and i am testing;

    it's a small washer of abut 3 mm height that is inserted between the nozzle and the PTFE element, after removing about 3 mm from the PTFE element. this is essentially a heat barrier..

    have been printing about 2 spools of PLA by now so i'm curious towars the results..

     

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    Posted · Teflon spacer replacement

    I am about to test my vespel as well, my setup is currently failing in retraction.

     

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    Posted · Teflon spacer replacement

    time for an update..

    almost a week and a half of printing XT, ABS, PLA and PLA-HPA almost non stop.. i think i printed a complete spool of PLA and a complete spool of XT.. and loads of ABS and PLA-HPA..

    i've had very good results so far..

    what i did do each time, after each print, 10 cm of cleaning filament and a cold pull with the taulman Nylon.

    for those that are not familiar with my setup, i have received a Vespel washer from 3Poro and have removed 3MM from a damaged PTFE coupler then reusing that with the Vespel Washer. the washer is about 3 mm heigh and sits between the hot end and the PTFE coupler.

    my experiences:

    i was very curious as how the Vespel washer would look. i did suffer from a few issues, but that was really at longer prints or very difficult prints. i had to put some PTFE spray in my bowden tube since it was causing friction. no other real issues reported. i did notice that i had some retraction issues. 3Poro notified me that the washer was 3mm and the PTFE coupler was 3.2 mm in inner diameter and that thatcould be causing issues.

    i have taken apart the hot end today and it seems this is indeed the case;

     

     

     

     

     

     

    as you can see, the PTFE coupler is completely burn and deformation free. i printed quite a few ABS and XT and without the washer i would definately have suffered deformation. looking at that i would say this is a great improvement!

    when taking off the sleeve however i did notice quite a bit of debris stuck in the sleeve;

     

     

     

    i cleaned this out, i also cleaned out my hot end by burning out all plastic.

    i will assemble it later this week and put everything back. i also drilled out the vespel washer to 3.2mm.

    so so far, great succes!

     

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    Posted · Teflon spacer replacement

    I should be having a velpel washer machined today. I would like to have a single hot end that I can use to print the entire range of materials. PLA to PC and everything inbetween.

     

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    Posted · Teflon spacer replacement

    not read the whole thread to see if you already tried this, but a bit of http://umforum.ultimaker.com/index.php?/topic/9107-deformed-teflon-fix-use-a-bit-of-bowden/?p=87788 but i think you are trying to isolate the hot from the cold zone a bit better?

     

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    Posted · Teflon spacer replacement

    @Korneel

    Loose the Harbor Freight Calipers like they were on fire!

    Trust me :)

     

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    Posted · Teflon spacer replacement

    Fluxline,

    It is believed that the vespel can withstand the sealing force of the spring at the elevated temperatures where PTFE softens and creeps. The vespel is also slick so the PLA does not seem to stick to it. Last but not least it seems to provide a heat break for the ptfe so the PTFE doesn't see the high nozzle temperatures.

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    Posted · Teflon spacer replacement

    thanks for the summary Evan. one of the issues, i believe, that the glass impregnated teflon insulator has is mechanical wear from the filament. how does the vespel compare?

     

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    Posted · Teflon spacer replacement

    I have been testing a thin vespel washer for some time now and it looks promising so far.

    The one I am testing is thin enough that you don't have to cut the teflon insulator.

    It looks like it does not have to be thicker than that to get the temperature of the teflon spacer down to levels below where it degrades. At least when you stay below 260 C.

    Another guy here is about to get a small batch of these made I think, so they might soon be available for people who wants to get one for testing.

     

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    Posted · Teflon spacer replacement

    Interesting stuff... late last year I had a quote from an Engineering company who supply Duratron PBI CU60. They would sell me a 1” x 12” rod which was the smallest practical size available to make isolators from, for £273.38 which I'd then have to machine myself. Or more realistically, have someone else do it :-)

    To supply the insulators already machined, they were quoting me £702 (for 12)

    which made it a somewhat pricey insulator...

     

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