Ninja flex

I'm just trying a print using the elastic, rubberised "Ninja Flex" material. (I'm printing a lens cap for a camera).

For anyone else who intends to try this stuff, after a lot of failures and experimentation, here is what I found works with this material:

Extruder 218 degrees, bed 0 (not heated). It sticks fine to my normal solvent cement - you may have to heat if using tape, but it is a sticky substance and would probably work fine on plain glass.

Disable retraction completely (set to 0). The rubbery filament is not well suited to feeding through a Bowden tube, and does not handle retractions well.

The material does not print well at speeds above 25mm/s or so. At higher speeds it tends to break up and form rubber granules similar to what you see after using a pencil eraser, and it does not fuse to the previous layer. With all print speeds set to 20mm/s, it works OK.

Dave
(#106)

Looks pretty good Dave.
You say it is not well suited to a Bowden tube - so how did you feed it?
Greg

Edited 1 time(s). Last edit at 03/11/2014 12:13PM by GregL.

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Ormerod #17

Quote
GregL
Looks pretty good Dave.
You say it is not well suited to a Bowden tube - so how did you feed it?
Greg

It feeds OK through the Bowden tube so long as it is under a reasonably constant pressure, but I found that it would occasionally stop feeding for a while following a retraction (but it self-starts after a short while), which is why I disabled retractions. Stringing is however an issue without the retractions - being rubbery it is like a compressed spring in the tube, and continues to extrude for quite a while after the feed stops. That was not an issue on the print I have just made because there are no non-printing moves across areas of space, so all strings fall onto plastic and are absorbed into the print. If you set retractions because stringing is an issue, I would think it would need to be quite big (6mm or more) to be effective because of the need to take up the "spring", and maybe keep a bit of a push on the filament feeding into the extruder to help it restart feeding. It is possible the feed issue is due to a problem in my extruder, (though it works fine with ABS). I haven't taken it apart to clean for quite a while, and it is possible that the hobbed bolt it a bit clogged. With ABS, the teeth "bite" into the plastic filament, but ninja flex just deforms temporarily so there are no teeth marks and possibly the grip is not quite as strong.

Dave
(#106)

Your timing is perfect Dave - I have some white Ninjaflex on order to try out. I saw adafruit using it for LED diffusers: [www.adafruit.com] and fancied a go. Your final print looks fantastic!

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RS Components Reprap Ormerod No. 481

That does look good Dave - on a scale of polypropylene (eg milk bottle lid) to silicone rubber, how flexible would you say it is, and on the same scale, how hard?

For the stringiness/retraction difficulty did you try slic3r's "Extra length on restart" (which the tooltip says is seldom needed - but this might be that one time...),

Ray

Quote
Radian
Your timing is perfect Dave - I have some white Ninjaflex on order to try out. I saw adafruit using it for LED diffusers: [www.adafruit.com] and fancied a go. Your final print looks fantastic!

Yes, after the first hopeless failures I almost gave it up as a no-go (I only bought a 10m sample to try), but I am pleased I persevered. I designed the cap with sides that slope in a bit (see Scad file - the "Grip" variable determines the slope) with the idea that the rubber would stretch and grip the side of the lens like an elastic band, and it has worked perfectly - the cap holds on tight but is easy to peel off and on. An ABS cap won't fit with such a slope on the sides, and with the slope lessened until it fits, an ABS cap falls off if you give the camera a shake - the Ninja Flex cap holds tight. It is also soft like a rubber band and so won't scratch the lens if it is inadvertently rubbed across it. I'm very pleased (and also with the camera bought for £50 last weekend - knocked off £10 because it was missing a lens cap!)

Dave
(#106)

Quote
rayhicks
That does look good Dave - on a scale of polypropylene (eg milk bottle lid) to silicone rubber, how flexible would you say it is, and on the same scale, how hard?

For the stringiness/retraction difficulty did you try slic3r's "Extra length on restart" (which the tooltip says is seldom needed - but this might be that one time...),

Ray

Yes, that might be an option that would have helped - I didn't try it and I sliced with Cura which I don't think has that option. I see that the link cited by Radian suggests an extruder temperature of 225, a bit hotter than the 218 I finally printed at, although I tried all temperatures up to 240 to try to stop it breaking up when it got to about the 3rd layer - till I realised that it was a speed issue not a temperature issue (which that link does not mention).

As far as consistency - it is pretty much the same as silicone rubber as far as feel and flexibility, but I'd say very slightly softer and not so stretchy. I still have a few meters left, and might print the same part again with slightly thicker walls - that one has 1mm walls, and I'm not sure how well it will wear - though it certainly feels strong enough and the layers appear well bonded.

Dave
(#106)

Sounds like it's well worth keeping some around then Dave, thanks very much for the info (especially for the handling tips- I'd probably have binned it after I did the fast run tbh )

Cheers

Ray

There is another supply for flexible filament - this one specifies its elasticity properties with a 'Shore' value (two different grades).
[mendel-parts.com]
Greg

Edited 1 time(s). Last edit at 03/12/2014 05:33AM by GregL.

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Ormerod #17

Many thanks to Dave for the setting suggestions.
I am mid print now using some Ninja Flex.
So far no bobbling, seems to be stuck onto the Kapton OK. Layers look like they are bonding well.
Its not just a plain rubber tube, the top tapers in to form a duck bill valve.

Edited 1 time(s). Last edit at 04/24/2014 08:10AM by balidey.

I like your fan - where did you find that?
Greg

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Ormerod #17

Yes, the slim 10mm fan, it looks like the original fan housing was made to suit it.
Cheap 2nd hand item from ebay. I think I have listed its details in another thread. Silent running, cools as well as the standard noisy one.

details on here, post 2.
[forums.reprap.org]

Edited 1 time(s). Last edit at 04/24/2014 08:45AM by balidey.

Quote
balidey
Many thanks to Dave for the setting suggestions.
I am mid print now using some Ninja Flex.
So far no bobbling, seems to be stuck onto the Kapton OK. Layers look like they are bonding well.
Its not just a plain rubber tube, the top tapers in to form a duck bill valve.

Looks good so far - let us know how it turns out and whether it works for your application. A tall tube structure might have problems because the head will tend to push the flexible part to one side if it encounters a slight bobble rather than riding over the obstruction.

Dave
(#106)

Couldn't take any decent pictures of it finished, camera phone is rubbish, so I will update in the morning with better pics.
But the item is great.
Its a 25mm bore, 45mm high approx 1.5mm wall that then tapers inwards to a slot, height is another 45mm above the lower cylinder.
Its a 'duck bill check valve' if anyone wants to google it to see what we were making.
The exact item we want was not available. A rubber moulding company wanted an order for 1,000.
Instead £5 worth of Ninja Flex from ebay is enough for us to print 4.
Its an odd material. Very flexible and soft on the roll, but when printed it takes on more of a plasticised feel to it. But still flexible enough for what we wanted it for. Squeezing the slot on the top of our check valve required very little pressure, it opens up nicely, springs back to the original shape.

So tempted to order 1kg of it now.

If the dual / triple print head ever gets up and running on the Ormerod I think a PLA / Ninja Flex dual material fused print would be amazing. Like a plastic / rubber co-extruded seal.

Edited 2 time(s). Last edit at 04/24/2014 05:09PM by balidey.

Just to add, I used Dave's settings for temp, well actually I used 215 for hot end.
Bed I used 45 but I am using Kapton, cleaned after every print with Acetone / nail varnish remover.
All speeds 20mm/s.
Zero retraction.

Quote
balidey
Couldn't take any decent pictures of it finished, camera phone is rubbish, so I will update in the morning with better pics.
But the item is great.
Its a 25mm bore, 45mm high approx 1.5mm wall that then tapers inwards to a slot, height is another 45mm above the lower cylinder.
Its a 'duck bill check valve' if anyone wants to google it to see what we were making.
The exact item we want was not available. A rubber moulding company wanted an order for 1,000.
Instead £5 worth of Ninja Flex from ebay is enough for us to print 4.
Its an odd material. Very flexible and soft on the roll, but when printed it takes on more of a plasticised feel to it. But still flexible enough for what we wanted it for. Squeezing the slot on the top of our check valve required very little pressure, it opens up nicely, springs back to the original shape.

So tempted to order 1kg of it now.

If the dual / triple print head ever gets up and running on the Ormerod I think a PLA / Ninja Flex dual material fused print would be amazing. Like a plastic / rubber co-extruded seal.

I am pleased to hear that you did not experience the problem I was concerned about. Yes, a hybrid part would be very useful in many applications, as well as printing parts with integral seals it would allow printing vibration damping mounts as part of a design rather than fitting separately, or elasticised skirts around parts etc. That's provided the ninja flex bonds to PLA and/or ABS OK.

I am always interested in hearing of 3D printed parts that have a practical use - it seems like the majority of designs I see (apart from printer parts) are trinkets and ornaments, with a few novelty items thrown in. My own designs have been mostly containers of one sort or another, which whilst having a practical use are not as satisfying to me as systems and machines.

One day I may have a go at designing a 3D printed pendulum wall clock driven by a traditional weight & pulley system. ISTM that almost all the parts should be 3D printable, though I think it would have to be quite large to work reliably. Just to make it different to most clocks, I'd give it a 24 hour face, and have a hand that shows the tide as well. Or maybe shows sidereal time.

Dave
(#106)

Edited 1 time(s). Last edit at 04/25/2014 07:38AM by dmould.

Anybody successfully printing hybrid ABS + NinjaFlex parts?

Thank you very much dmould i got The Filamente 3 days ago but didnt try it out yet