by fulg » Fri Mar 25, 2016 12:14 pm
It's a bit late for a reply, but for the benefit of others... I recently printed some NinjaFlex with my ORDBot (with an EZStruder + E3D V6) and ran into a similar issue. The problem is clearly visible in your photo: the filament is not supported at all after exiting the hobbed bolt and before entering the hotend/bowden tube, so it will buckle while printing. I had to modify my EZStruder bracket to fix this and support the filament from all the way up, and eliminate any air gaps or snags (which are not an issue with hard filament).
You have to go really slow for flexible filament, around 20 or 30mm/s at best. Similarly, the filament speed has to be uniform for all operations: do not slow down while printing the first layer, do not print the external outline slower, do not print the infill faster, do not retract faster than your print speed.
With these tips I get great prints from my NinjaFlex filament. Hopefully you also sorted it out by now!
Cheers,
Ben.