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Flex Not working!


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Posted (edited) · Flex Not working!

I have bought materials from Ultimaker, which are PLA Flexible white and PLA Flexible black, however, I'm having trouble using these materials. Every time i use them and as i start printing, the material get jammed and stuck in the material feeder from the back. I have asked about it and have been told  to use vegetable oil. Then another source told me not too since it might damage the machine.

I hope someone could answer me on how to use these materials without having trouble!

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    Posted · Flex Not working!

    Definitely you need oil as without oil there is huge friction in the bowden. I have not tried vegetable oil but it probably works fine. I use "3-in-1" oil which is just a basic light petroleum oil. Sewing machine oil also works will.

    it will not damage the printer. It may cause some slow build up on the inside of the nozzle over many dozens of prints. Maybe. Probably not. But you can just change the nozzle after you go through a few rolls of filament.

    For ninja flex which is even more flexible and more difficult I print very very slow (10mm/sec) and hot (240C). I don't recommend going to 240C right away though - start with the oil - make sure you can see the oil inside the bowden. Just one or two drops is enough but unspool a few feet of filament and put one drop on the filament *before* it goes through the feeder also.

    Then start printing slow - the bottom layer - if it is squished too much the filament will have trouble coming out and you will have your issue (tangle at feeder). Go into the tune menu and slow the feedrate down to maybe 20% of normal just to see how things work. Or maybe adjust the 3 leveling screws by the same amount to give it a little more room to come out if it's not coming out. Then try speeding up the feedrate faster and faster until you see it's underextruding or having trouble at the feeder and back off. Higher temps help also but don't go above 240c.

    Consider printing out the IRobertI feeder (google it). It's better at flexible filaments than the regular feeder.

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    Posted · Flex Not working!

    I think you must use the Robert feeder. I tried the Flexible filament and the standard feeder simply quashed it flat. You can adjust the tension on the Robert feeder and on my UM2 it now feeds perfectly.

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    Posted · Flex Not working!

    I just printed out a 4hr print with ninjaflex semiflex yesterday. Came out great at (20mm/sec), 210C with 145% flow (had to change while printing). I also have the iRoberts feeder, which is a huge help.

    Another thing too, if you have printed a while without cleaning (Atomic method) this could be causing the jams. I know I had to clean after every print with flexible material.

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    • 3 weeks later...
    Posted · Flex Not working!

    I tested the UM PLA FLEX a few days ago. And was very impressed! It is FAR easier to print than Ninjaflex, but not as flexible.

    I printed on a stock UM2 with standard feeder, and it printed great first time with PLA settings. I printed at 15mm/s, but I think it could have gone faster. I never had any luck with Ninjaflex at anything faster than 15 so thats where I started.

    I printed a hollow ducati tire, and it came out flawless. Looks better in real life than the picture.


    The layer bonding doesn't seem quite as strong as ninjaflex (it tends to crack along the grain if its bent sharply) but it certainly has a much better finish. Slightly harder than Ninja flex as well. But at least it requires no additional tinkering of your machine.

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    Posted · Flex Not working!

    The layer bonding doesn't seem quite as strong as ninjaflex (it tends to crack along the grain if its bent sharply)


    I used the flex pla from makerpoint.nl which is probably a bit similar. .. try printing it hotter to improve the layer bonding.

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