Dear all!
Nicolas from Inria Prima research team has 3Dprinted two cool Poppy hands (ninjaflex materiel)
They have a very smooth touch and we wont brake them (fingers) during our trips 
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Ninjaflex is really difficult to print the result is beautiful! What is the printer used to do this?
Hello,
Nicolas uses a Makerbot to do the hands.
I will ask him to join the forum to better explain how he did print them 
have a nice day.
In fact there is a bit of beard beetween the fingers that the picture doesn’t show but I think Nicolas has indeed a good practice of flex printing and I was impressed when I saw what he managed to print !
I must add that using flex material makes engaging the screw in the nuts is kind of tricky.
As I was in a hurry the way I found to secure the hands was by wedging the bolts with a thick piece of folded paper that kept them in their (soft and loose!) housings.
A cleanest way to make the mounting of flex hands easier could be to print small rectangular PLA docks with four recesses to receive the end of the screws while blocking the nuts in their housings.
very impressive ! It opens also interesting possibilities to create Poppy creatures which whole body is soft like this, which in turn creates very interesting scientific challenges, such as “How to loco mote with a flexible body?”
Hi all,
I’m the Nicolas mentionned in the first post.
I used our Makerbot Replicator 2 to print the hands.
The filament used is the Flex from 3dpremium (you can buy it here), with printing temperature from 190 to 240°C.
I think the version of the photo were printed at 225°, but there is still this annoying beard between the fingers (but a lot less than the 230° try).
The main difficulty is to find the perfect temperature. If it’s too high, you have beard, because when the printer tries not to print between the fingers, it melts anymay. But if it’s too low, it clogs (all my tries at 220 and below did).
However I think it’s possible to lower the temp if we lower the speed too. I printed with the default speed of the replicator (90 mm/s) and it’s probably too much. I’ll try this later if I get the time (and if the printer is repaired 
)
Otherwise the parameters were almost the standards. 10% infill , 0,20 mm layer height and 1 shell.
The hand was placed with the finger pointing up and just a few supports inside the hand and at the bottom, just around the square for the screws.
I did this with Meshmixer (website), using the support generator, then removing by hand all the supports that were in contact with the external surface of the hand (to avoid bad texture, there are not needed anyway), but keeping the ones inside the hand (not inside the holes of the finger, there are useless too). Then Meshmixer sent the model to makerware, where I printed without support nor raft options.I can provide the model with supports if needed.
I hope it helps. I’ll be glad to answer any other questions you might have.
2 Likes
Hi @moutemoute38 and welcome to the Poppy forum,
Personally I tried to print Ninjaflex on my replicator 2X and it was really difficult. You don’t have any trouble with retraction and the torsion of the filament inside the extruder?