Same gcode. Different speeds and temps. Ninjaflex on Makerbot Replicator. ~30 mm/sec @ 215°C vs ~15mm/sec @ 230°C.
The better looking print was the cooler/faster print.
Which version of the extruder drive mechanism is your replicator Using? My testing indicated that it should be nearly impossible to print ninjaflex on one of those due to how easily it buckles, though I don’t think I’ve ever taken my speed all the way down to 15mm/s, even on my Cupcake or the Huxley I had before that.
One of the Ninjaflex folks have been using the Rep 2 with the MBI extruder upgrade (see http://www.pp3dp.com/forum/viewtopic.php?f=11&t=23329). In my case, I have been using a modified whpthomas extruder upgrade (http://www.thingiverse.com/thing:156192) which I hacked together to add a filament guide.
If I feed too fast, it starts to buckle and then wraps around the stepper shaft (!!!) – but I’ve been able to back it out without too much difficulty. At 30 mm/sec, it’s not been a problem.
The only problem, in my opinion, is that it is still a bit stringy at the above setting. Perhaps lowering another 5 degrees will help that further.
With a printing speed that low and a travel speed over 150mm/s (is anyone still using speeds slower than that?), there should be very little stringing, even without retraction.
This material seems to be rather stretchy - so that the strings do not break as PLA or ABS would.
can ninjaflex be printed on a non-heated platform?
Yeah, I’ve printed it on unheated blue tape.
I barely warm up my Kapton. I set it at 28. Should be ok. Especially because the urethane probably will absorb any stresses during printing.