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AndreCarvalho

Ninja Flex on UM 2+

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Posted · Ninja Flex on UM 2+

Oh also - ninjaflex doesn't need a very hot bed. Whatever your bed temp is, lower it by 10C. Probably 35C is warm enough for ninja to stick well.

Unlike most plastics, Ninjaflex doesn't have warping issues - it won't warp off the bed because it is so flexible it would rather just bend a little.

So you can probably go colder on the bed. The heat from the bed also probably makes that overhang a bit ugly.

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Posted (edited) · Ninja Flex on UM 2+

I've been printing with Cheetah for a while now with varying degrees of success. BuildTak sheets help a lot in keeping parts stuck to the bed. My usual print settings are:

Print Setup:

Nozzle: 0.4 mm

Layers: 0.2 mm

Speed: 20-30 mm/s (all)

Fill Gaps Between Walls: Nowhere

Retraction Extra Prime Amount: 0.128 mm^3

Material Settings:

Temp: 235º

Bed Temp: 70º

Fan Speed: 100%

Flow Rate: 130%

Retraction Length: 6.0 mm

Retraction Speed: 20 mm/s

I have had some success printing smaller layers but if there are too many retracts it begins to under extrude and if you reduce the retraction length you get a lot of stringing. I've thought about buying a Luzbot just for doing Ninjaflex as it has a direct extruder instead of a bowden.

Edit: Thought I should add that I've found keeping the filament dry is critical. Any moisture will cause under extrusion.

Edited by Guest
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Posted · Ninja Flex on UM 2+

Has anyone had any experience with the Bondtech extruders? They have a video of them printing ninjaflex at 60 mm/s and I was wondering if it would be worth the upgrade?

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Posted · Ninja Flex on UM 2+

Bondtech is great but I don't think it will help you on ninjaflex. I assume it wasn't a bowden printer in the video? I have a bondtech on one of my printers and I'm pretty happy with it. Although the UM2+ feeder (the white feeder - not the black feeder) is easier to load and unload filament. bondtech is good at this but not as good as the "plus" feeder.

But Bondtech has about twice the pushing strength. So it's great for really fast, low quality prints.

But for ninjaflex not so much. It's like pushing on a string. You can push harder but that string isn't going to move any faster.

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Posted (edited) · Ninja Flex on UM 2+

They have an UM2/UM2+ kit that just replaces the stock feeder so I would assume it's still a bowden setup. I have found the stock extruder slips with TPU/TPE filements. I have some SemiFlex and standard NinjaFlex and I can't get those to print because the feeder just slips before enough pressure can be built up. I've only really had success with NinjaTek Cheetah and Armadillo. Do you see any improvement with the bondtech vs the stock feeder with ninjaflex or are they comparable?

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Posted · Ninja Flex on UM 2+

Wow! On an Ultimaker! I don't remember if I've used ninjaflex on my bondtech yet. I'm surprised it would make much difference. Typically if I print as fast as that video (I print 10mm/sec for ninjaflex) it all bunches up in the bowden - like an S curve race track. More like a spiral actually. Like DNA. So I like to print very slow such that it doesn't bunch up. And hot (240C).

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Posted · Ninja Flex on UM 2+

Wow!  On an Ultimaker!  I don't remember if I've used ninjaflex on my bondtech yet.  I'm surprised it would make much difference.  Typically if I print as fast as that video (I print 10mm/sec for ninjaflex) it all bunches up in the bowden - like an S curve race track.  More like a spiral actually.  Like DNA.  So I like to print very slow such that it doesn't bunch up.  And hot (240C).

Sounds like you should give it a try then ;)

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Posted · Ninja Flex on UM 2+

There is a big difference with Bondtech vs. the stock feeder on the UM2+ even though others have not said so. The stock feeder "squeezes" the filament since it only has one gear...while Bondtech will gently move the filament since it has dual gears that will have a good grip on the filament without "squeezing" it.

Just take a look at the Bondtech drive gears and then look at the stock gear and it will be obvious how much better it works...especially if you have a lot of retractions :)

That said...i'm not using a bowden setup anymore...i'm using the ZGE which also uses Bondtech gears.

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Posted · Ninja Flex on UM 2+

So, after oiling the bowden, the small to medium sized prints come out very good on my UM2 with Robert's feeder.

However, the larger ones, that can take 6-8 hours are impossible yet. The Ninjaflex filament eventually slips away from the feeder gears and ruins the print.

I use the recommended settings:

220C

40-50C bed

30 mm/s

no retractions

2mm layers

103% flow

And, of course, the Snap On Guide is on the feeder but eventually, it is not enough.

Any ideas how to make it more reliable?

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Posted · Ninja Flex on UM 2+

I haven't [dared] try regular NinjaFlex (yet) but would be curious what you find out.

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Posted · Ninja Flex on UM 2+

I haven't [dared] try regular NinjaFlex (yet) but would be curious what you find out.

That doesn't sound very encouraging... :-(

If the experts like you have no clues, than could it be that UM2 simply can't handle that?

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Posted · Ninja Flex on UM 2+
@shurik - 30mm/sec is much too fast in my testing (I just did a ninjaflex print a few days ago). I recommend 10mm/sec and oil the filament.

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Posted · Ninja Flex on UM 2+

There is a big difference with Bondtech vs. the stock feeder on the UM2+ even though others have not said so. The stock feeder "squeezes" the filament since it only has one gear...while Bondtech will gently move the filament since it has dual gears that will have a good grip on the filament without "squeezing" it.

Just take a look at the Bondtech drive gears and then look at the stock gear and it will be obvious how much better it works...especially if you have a lot of retractions :)

That said...i'm not using a bowden setup anymore...i'm using the ZGE which also uses Bondtech gears.

Interesting. So if the filament is squeezed will that mean it over extrudes? Or under extrudes or neither? These can be compensated by changing the flow but I want to know. And convince me please - why would it over or under extrude - I have a strong desire to understand.

I'm thinking under extrude? you are passing the stretched out version at the correct speed but then it leaves the extruder and shrinks again. So it feeds too slow? Right? In my experience though I tend to get over extrusion. I think because of water content/boiling. Not because of the feeder.

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Posted · Ninja Flex on UM 2+

No, I was just saying that with Bondtech gears you have a higher success rate in feeding the filament without grinding or slipping the filament since those gears do not need to "squish" the filament to grip it.

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Posted · Ninja Flex on UM 2+

And what settings worked for you, so others can learn from you!

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Posted · Ninja Flex on UM 2+

Well, that wasn't simple at all.

I cut pieces of flex long enough to be inserted into the bowden and then inserted the standard PLA into the feeder's wheels. That was enough for approximately 1/2 hours of printing, then a new piece of flex had to be inserted. The whole print took almost 7 hours...

Other than that, everything was default - 220C, 40C bed, 0.2mm layers, 30mm/sec, 103% flow.

The surface finish was perfect, the customer was ecstatic, and that what's really matter.

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Posted · Ninja Flex on UM 2+
@shurik - I add a drop of oil every 30 minutes or so - did you try that before you did this pla-pushes-ninja method?

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Posted · Ninja Flex on UM 2+

@shurik - I add a drop of oil every 30 minutes or so - did you try that before you did this pla-pushes-ninja method?

Oh, yes, absolutely so. In fact, I kept oiling every piece of the flex before inserting, and kept an oiler (ex-dust remover) around the flex that went into the bowden. That probably made the filament even more slippery.

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Posted · Ninja Flex on UM 2+

I wanted to post a follow-up to my experiences earlier in this thread.. I just installed the UM2 extrusion upgrade kit yesterday. The updated firmware had a filament setting that was close enough for the NinjaFlex Cheetah recommended settings so I used it. Nozzle temp is 235ºC, 70ºC on bed, and 0% on fan. I am using one of the STL files I configured back in January so I'd have to open that up in Cura to see exactly what settings I landed on (or if they deviated from what I posted earlier).

Long story short is, out of the gate... this NinjaFlex Cheetah filament (through the new extruder) is printing perfectly!!! I will move on from the Cheetah to the regular NinjaFlex looking through tips/suggestions in here to see if I can get that filament to finally print!

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Posted · Ninja Flex on UM 2+

Hi all, and future readers,

** Buy Yourself A PTFE Bowden Tube **

On my UM2+ I have printed NinjaFlex with mixed results a year ago.
Last week I used it again for a new project and had difficulties finding the right settings. Adding 5-10% flow is essential but also on high temp and freshly cleaning (atomic pull) nozzle worked well 1 print, failed the next one etc. Under extrusion from the start or suddenly after quite some layers. With the clean nozzle the only problem could be the feeding. Cleaning the feeder and fresh undented NinjaFlex filament didnt fix it.

So I expected the flex filament being spaghetti in the non-PTFE Ultimaker bowden tube would cause too much friction at those under-extrusion moment. And indeed, sometimes the filament looked to be pushed fairly straight, but often when under good pressure it curled in S-shape/zig-zag like way as the UM bowden inside dimater is larger than the 2.85-3mm filaments.

I read good stories about the lower friction of PTFE tubes. Bought one (from the RepRap guys here in The Netherlands) and after install print was just fine. You also really feel the different in friction when you compare by feeding filaments through both.
The one I bought from RepRap also has a smaller inside diameter I noticed, leaving less room for heavy zig-zag'ing which I think causes the heaviest friction.

Buy yourself one if you have trouble. You need 73cm, they often are sold per 10cm.
Only downside, they are not fully transparent. Translucent to almost solid white. If you really like to see your filament moving or spot dirt in your tube this might be a disadvantage. If not, nothing to loose here.

Good luck guys

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