Ramming (and speed) settings for flex e.g. NinjaFlex


I’d like to print with NinjaFlex, as at Shore 85A it’s the most flexible material I have found for 3D printing.

I can load it into the MMU ok, but what are the speed and ramming settings, please? At the moment the ramming means I have two filament ends joined by a thin fibre, which stops everything working.

Or if you don’t have suitable settings please can you give the ramming settings for the Prusa Flex material, at Shore 98A?

Please can you explain what the different ramming settings mean so I can experiment?


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The ramming settings are feature for advanced users and we don’t have any guides available for them - yet. There will be some in the future :)

You can find the FlexFill/SemiFlex filament profile in Slic3r PE - it has it’s own ramming settings.

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Hi Filip,

I've just updated to Sil3r Prusa Edition 1.41.1+win64 (for MMU2 Config)

I can't see the FlexFill/SemiFlex filament profile under the Filament Settings.

But I can see the FlexFill when I am in the Mk3 Config.

Please can you tell me when a FlexFill/SemiFlex filament profile is available in Sli3r for MMU2 config?

thanks so far.


When in MK3 (or MMU2 single) mode, flex filament type does appear, but when in MMU2 multimaterial mode it doesn't. I've tried different filament configurations without sucess. Flex filaments always get stuck in the selector or into the extruder while loading or unloading. Terribly frustrating.

I regret having bought MMU2 so early in the development process, by far seems to be an unfinished product.


Hey there! I'm not from the Prusa Support team but may be able to help.

Although I haven't tried using any flexible filament with the MMU2, I would definitely assume there would be severe problems with loading the filament from the selector. The MMU2 is basically a semi-bowden setup, which flex doesn't really work well with.

I think the reason you can't use flex filament (or at least there isn't a preset for it in Slic3r PE) has to do with the fact that although it probably prints fine on its own, even with the long PTFE tubes and stuff, having to tool change to and from a flexible filament might be disastrous.

Also, Petrus, I feel what you're going through. Not sure when you got your MMU2, but I got mine in late November and didn't get it to even make a successful print for 2 weeks. Flex just seems impossible in my opinion.

I hope this helps, and good luck with your adventures into the unknown! I hope it works soon!


P.S. What are you trying to print with multimaterial flexible???


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