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Converting UM2+ to use 1.75mm Filaments


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Posted · Converting UM2+ to use 1.75mm Filaments

Hello everyone,


I have a couple of Ultimaker 2+ printers and I’m looking into the idea of converting one of them to take 1.75mm filaments.


I produce a variety of models and components for board/tabletop games and have been using eSUN PLA+ almost exclusively for the past few years but recently discovered that eSUN are no longer producing their 2.85mm range due to low demand. While I am still able to find some of the filaments I require, it is becoming increasingly hard to do so and, ultimately, there will come a time when it is not longer possible.


I have received a number of recommendations for alternative filaments to try out but in every case there would be some form of compromise on either price, colour range, mechanical properties, etc, etc… not to mention the the time and effort that I would need to put into experimentation and testing while I try to find the best replacement. Given all this, it occurs to me that converting either one or both of my machines to work with 1.75mm filaments might be an easier/faster solution as it would allow me to continue using my preferred brand while maintaining continuity for my customers.


I have read a number of articles on this subject but, while it seems clear that it is possible to do, these articles vary widely in their claims from “You don’t really need to do much” to “You need to change everything!”. Some of the solutions I’ve found look like they may cost me a bit and, while I’m ok with this in principle, I don’t have endless cash to throw at this problem so I’d like to be better informed before I taking any action.


I would be very interested to hear from anyone who has tried this conversion (successful or not) or anyone who uses eSUN products and is facing the same dilemma.


Many thanks in advance


- J   

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    Posted · Converting UM2+ to use 1.75mm Filaments

    3dsolex.com has a good solution for the hot end.  All you really need is the teflon part but with a 2mm hole in it instead of 3.1mm.  It costs the same for either part.  Get a few as you are supposed to replace that part every 300 to 1000 hours of printing anyway.


    In addition you can get their 1.75mm conversion kit which includes an olsson block with a 2mm hole also.  And a dual bowden where the inner bowden I.D. is... you guessed it... 2mm.  You can also get nozzles with 2mm I.D. from 3dsolex or dozens of other manufacturers (china, ed3v6 style nozzles from e3d-online or dozens of other sellers, and 3dsolex of course, also bondtech, really many other manufacturers).  You really don't need the smaller nozzles.  It does make cold pull easier but over the years I rarely do cold pull anymore.  So the nozzle thing is optional.


    You really don't need the bowden.  But over many years the smaller filament will carve a groove into the larger bowden so it will probably wear through faster?  I don't know.  You really don't need the bowden but it's cheap.


    However the bowden is really nice because it's hard to get that little 1.75mm filament into the little hole in the top of the teflon without the bowden to guide the filament in.  This is just when loading filament.


    Finally the feeder.  The 2+ feeder will work fine.  The 2 "original" feeder not so much and you would need to upgrade to an iRoberti feeder.  Preferably with the meduza 2X upgrade.  But if you have a 2+ you don't need to do anything.


    So... total cost: about 18 euros for the teflon part.  Which you need to replace anyway every 300-1000 meters of filament (yes I said hours before - in my experience - looking at people's printers - the 2 numbers are usually about the same for 3mm filament and typical printing speeds).


    Oh and... don't do it.  lol.  You can still buy lots of 3mm filament (it might be called 2.85 or 2.9 or 3mm but you hopefully already know this).  I don't know about in Europe but in USA printedSolid is great for having tons of 3mm filament.  Along with amazon.  Amazon has their own cheap brand.

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    Posted · Converting UM2+ to use 1.75mm Filaments

    Oh and filament diameter is set on the UM2+ in the materials section.  You will need to change all the filament types to have 1.75 diameter filament.  There is a trick where you can save all your material settings to the uSD, then bring it to a computer and edit the file and then bring it back and reload the material settings.

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    Posted · Converting UM2+ to use 1.75mm Filaments

    I have a few links.  This is good instructions with nice pictures:  gr5.org/med/


    I only sell to USA but there is a link to print the parts and a link to the software.  You will also want to print the iRoberti feeder.  here are direct links to the stl files:



    If you print the iroberti, use the 38mm version of the yoke.  Description of needed hardware for the meduza is in the first link.  No hardware is needed for the iRoberti (it is designed to use parts from the existing um2 original feeder).

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    Posted · Converting UM2+ to use 1.75mm Filaments

    I used to work with eSun too but have now been using some of Matterhacker's filaments since they have some of the same colors. They actually were a bit cheaper, especially the more you buy. They don't have all the colors, but they have a wide range of them. Not sure if that helps.

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    Posted · Converting UM2+ to use 1.75mm Filaments

    Hi all, apologies for taking so long to respond, I was involved in a bit of an accident and have had other things to worry about for the last couple months but it's time for me to pick this quest back up again.




    Thanks for the comprehensive response, I figured the TFM would be the most important bit to swap over. I plan to grab one shortly and do some testing but I suspect I will go for the whole conversion kit before too long. I can see what you mean about the Bowden tube too, I was hoping I could avoid replacing it but I imagine my future self will resent me if I don't. Thank you also for clearing up the issue of the feeder. I've watched several tutorials that strongly urged me to replace it but as these were almost exclusively by people claiming to sell me the very feeder I needed (and always at the best possible price!), I was naturally suspicious. Anyhow, unless the conversion kit turns out to be prohibitively expensive it looks like this conversion won't cost much more than routine maintenance. 


    So just to double check, to do a full conversion for 1.75mm filament I'll need the following:


    - Replacement Teflon Bit (TFM) with 2mm I.D.

    - 3dSolex 1.75mm Conversion Kit (Olsen Block)

    - New Nozzles with 2mm I.D.

    - Replacement Bowden Tube with 2mm I.D.


    I've had a look at 3dsolex.com and I can't seem to find exactly what I'm looking for. This isn't the first time, its a bit of a curse, certain websites just seem to hate me. I'm thinking of contacting 3DSolex directly but if you've got links for various products to hand feel free to drop them here.


    I'm afraid I more or less forced into this approach unless I want to go through the process of finding a 




    On 1/31/2023 at 4:02 PM, 3dprntz said:

    I used to work with eSun too but have now been using some of Matterhacker's filaments since they have some of the same colors. They actually were a bit cheaper, especially the more you buy. They don't have all the colors, but they have a wide range of them. Not sure if that helps.

    I appreciate the advice, I'm based in the UK and I can't seem to find anyone supplying these Filaments outside the US. 

    If you've got a link for a European supplier just let me know.


    Thanks again



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    Posted · Converting UM2+ to use 1.75mm Filaments

    Pretty much anyone who sells 1.75mm filament sells 3mm such as eSun for cheap filaments and colorFabb in Netherlands for premium filaments (their nGen is pretty amazing stuff if you want higher temp filament that prints just like PLA).  However they may call it "2.9" "2.85" or "3mm".  It's all the same thing but when there is only one size for 1.75, it's harder to fine the 3mm.  Resellers are all over europe.  Even Amazon has their own brand (I think it might be eSun?).


    3dsolex may have shipped all his 1.75 stock.  I don't know but I see the ptfe part for 1.75 here - there is a n option for 1.75 once you load the page:



    So as you can see on the above link there is a way to switch between 2.85 and 1.75 filament.  That ability used to exist on many other pages including bowden, nano kit, olsson kit.  Not anymore.


    I strongly suspect you are out of luck.  He probably sold all his stock and decided not to buy anymore.


    However I do see some aliexpress sales that have 1.75 version of the olsson block - this one is so cheap - cheaper than a cup of coffee at starbucks:



    Free shipping.


    I don't know if the block has a 2mm hole or a 3mm hole.  Same with the nozzles.  but *something* must have the smaller diameter.


    Don't worry about the bowden.  Although if you really want to look - you can contact ptfe tubing sellers on alibaba.  You need a 2X4 bowden for the inner bowden (4mm OD, 2mm ID) - that's what 3dsolex had.  Not hard to find.  The hard part is then you need a bowden that is 6mm OD and > 4mm ID.

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    Posted · Converting UM2+ to use 1.75mm Filaments

    @gr5 Thanks again for the info. 


    I've ordered the Olssen Block and a few TFNs. Im a bit suspicious of the Olssen Block as I find it a little hard to believe that something so cheap can solve my problem but I figure I'll just go without a morning coffee one day next week and that will cover the cost if it turns out to have been a mistake. As for the TFN, I've always found it useful to have a few spares knocking about and I figure I can just drill them out to 3mm if nothing comes of this venture.


    So, that just leaves the Bowden Tube. I've found a couple of alternatives that look like they meet the specs you've outlined but I just wanted to check a couple of things before I go ahead with the purchase. Clearly I need the 2mm ID to guide the 1.75mm filament into the hot end and a 6mm OD (my current BT's are actually 6.3mm OD) to fit the clips but it kind of sounds like you are suggesting that I need two separate BTs (one 6x4 and one 4x2) and that I slide one inside the other. Have I got this right? and if so why would one 6x2 BT be unsuitable?


    Also, while I'm here, in your first post you said:


    On 1/30/2023 at 2:25 PM, gr5 said:

    Oh and... don't do it.  lol


    Any chance you could expand on this?


    Given that my preferred filaments are no longer being produced at 2.85mm diameter and current stocks will inevitably run out at some point I don't feel like I have much choice. I could, of course, change filament manufacturer but based on the time and effort it took to find one I like in the first place altering one of my printers seems like a much less costly option and even if it doesn't work out in the end it feels like the place to start. Are there any flaws in my reasoning that stand out to you? 



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    Posted · Converting UM2+ to use 1.75mm Filaments

    A 6X2 bowden probably would be too stiff to flex enough for the UM2.  Also I don't think anyone cells such a thing. 


    Even after you get all that you do need to 3d print a tiny little plug to keep the inner bowden from getting eaten by the feeder when it reverses direction.  On retracts.  Or filament changing.  You don't want that inner bowden going out through the feeder.


    The tiny plug is trivial to design but you probably will have to print and tweak it 2 or 3 times to get it perfect (I had to).


    Regarding "don't do it".  I feel like locating a new supplier is easier than the modifications.  Also are you 100% sure you can't get your favorite filament in 2.85/3mm variety?  Every other time someone claimed this I found the exact filament they wanted.  They just weren't using the "store" website properly.  This could be the one time I'm wrong.  Maybe call the supplier.  Maybe they don't sell it in the store but they have a few scraps (for them say 100 spools) left over.


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    Posted · Converting UM2+ to use 1.75mm Filaments



    I'm doing the same conversion (plus a few extra mods) on an UM 2.


    Can you refer to me where you found 2mm TFN couplers?



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    Posted (edited) · Converting UM2+ to use 1.75mm Filaments

    EDIT: Nevermind, I wasn't attentive enough to find that a link had already been given.
    (No way to actually edit posts on this forum isn't there?)
    EDIT EDIT: Oh wow, sorry for making such a ruckus, I believe the edit button wasn't there before since I was a new user. 🙂

    Edited by imTeet
    Confusion related to forum posting system...
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