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Don't throw away your old UM2 PTFE coupler


Nicolinux

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Posted · Don't throw away your old UM2 PTFE coupler

If you have been printing a lot, you might have had to change the PTFE (teflon) coupler on your UM2. But you don't need to throw the old one away. Just cut off the offending tip and you can keep using it. Just make sure you don't cut too much away. I'd say no more than 2mm - 2.5mm.

The coupler will be inserted further down inside the metal thingie (what's its name?) but it still works.

coupler1.thumb.jpg.2f432be5fd2229b5fedd919541871514.jpg

coupler2.thumb.jpg.1971097bbf8a14f8b519d9ded6429882.jpg

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    Posted · Don't throw away your old UM2 PTFE coupler

    My first coupler was deformed really badly after almost a years worth of use, so even cutting off 3mm wouldn't have helped, I guess it all depends on how much you push it, and surely you are more prone to the walls collapsing as the PFTE has been taking the heat from before. Still a good fix for those who replace it every five minutes. I hate the PFTE most about this printer. If you dont rely on the printer to do as its told, then its not so bad, but if you click on change material and expect it to come out every time then i would be changing the PFTE every five minutes.

    If you heat up the bed before and move the material till it comes out just before you kick a print off, you can still easily work with a dying PFTE coupler.

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    Posted · Don't throw away your old UM2 PTFE coupler

    For anyone attempting this, make sure the cut is absolutely straight and that the end of the coupler is in contact with the neck of the heater block. If not, you'll have leaks and sad times. (gives me horrible flash backs to the UMO with the original hotend)

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    Posted · Don't throw away your old UM2 PTFE coupler

    Actually having a bit smaller PTFE might be a good idea anyhow, specially with the olsson block, it will give more room to set the block a bit higher without adding more spring pressure. I think you'll need to use some sort of helping hand tool to make the perfect cut as otherwise you'll have leaks before you know it.....

    Maybe we need to design something like this for the PTFE....

    https://www.youmagine.com/designs/bowden-cutter-4mm

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    Posted · Don't throw away your old UM2 PTFE coupler

    You will also need a blade that's only sharpened on one side.

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    Posted · Don't throw away your old UM2 PTFE coupler

    Nice

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    Posted · Don't throw away your old UM2 PTFE coupler

    I have done the same when not having any spare and wanting to keep on printing, but i used a lathe instead of a knife, it works for some time, but it is not 100% more time but more like 30-40% more time.

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    Posted · Don't throw away your old UM2 PTFE coupler

    I've been looking in my toolbox but a blade sharpened on one side seems rare... any tips?

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    Posted · Don't throw away your old UM2 PTFE coupler

    Chucking it up in a drill and using any old sharp blade/fine tooth saw ought to do it, no?

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    Posted · Don't throw away your old UM2 PTFE coupler

    Whats the difference? I mean you could use a normal blade and sand it to get the exact straight cut.

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    Posted · Don't throw away your old UM2 PTFE coupler

    Anyone had any experience using the ones you can buy on aliexpress? Seem a lot cheaper....

    https://www.aliexpress.com/cheap/cheap-ultimaker-2-ptfe-coupler.html

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    Posted · Don't throw away your old UM2 PTFE coupler

    Yeah, they are pretty crappy in quality, they get them made in a cheap grade of PTFE and kind of works for a while, but not long-time.

    Get the new TFM coupler from the UM2+ and the rigid spacer, or just the TFM and print a spacer, and it will last way longer than the original UM2 PTFE coupler.

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    Posted · Don't throw away your old UM2 PTFE coupler

    Anyone had any experience using the ones you can buy on aliexpress?  Seem a lot cheaper....

    https://www.aliexpress.com/cheap/cheap-ultimaker-2-ptfe-coupler.html

     

    Those are teflon. The newer Ultimaker part "TFM" and the 3dsolex part "TFT" are a newer, much more expensive material that can handle higher heat without deforming so soon.

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    Posted · Don't throw away your old UM2 PTFE coupler

    In my couplers usually the bottom inside 2mm are burned, and the next 3 to 4mm have severe dents. So cutting all this off is not really an option anymore for me, unfortunately. Then I don't have anything left... :-)

    However, what does help a little bit for me is taking a long brass M3 screw or M3 thread, rounding off one end (so it has no sharp edges), and use that as a file to gently (!) scrape the inner walls of the coupler. This will scrape off burnt residu that might block the path. I do this while doing an atomic pull. No need to remove the coupler from the machine. Just poke through the coupler from above with the M3-thread, but always very gently and lightly. Don't slam it into the nozzle.

    It has to be a brass screw: nylon is too soft, and steel or inox is too hard: that might damage the nozzle-inside and eat too much material away from the coupler.

    After that, I do another atomic pull to remove the grinding dust and debris, so it will not block the nozzle or make the next print dirty.

    This does not do any miracles, but you may be able to use the coupler a few more weeks, for example when you ran out of spares.

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