3D Printed Ninjaflex – First Test

I’m sure if you’ve been 3D printing for even a short time, you’ve heard of Ninjaflex – a brand of flexible filament for your FDM printer that has rubber-like properties, rather than the usual rigid plastic parts that are more common with ABS or PLA filaments. While I’ve known about them for many years, I’ve never risked clogging my printer after hearing some bad experiences with these softer materials. Until this week!

I’m currently working with fashion postdoctoral researcher Mark Liu, who purchased a Wanhao Duplicator i3 v2.1 for some of our research – not coincidentally, it’s identical to my home Cocoon Create 3D printer. We decided to give the Ninjaflex a go to see if it would print, and if so, what sort of quality we could get since the printer and replacement parts are cheap if we really screwed up! Photographed above is one of our first successful prints, although the truth is we had quite a few failed attempts getting to this point as we experimented with settings and carefully watched each print. The primary settings we are using for these first tests (based off the recommended settings for Ninjaflex which are available in the Printing Guidelines) are:

• Extruder Temperature: 230°C
• Build Plate Temperature: 40°C
• Print Speed: 15mm/s
• Layer height: 0.2mm
• Retraction: 5mm (I think this is too much and we will try 0mm or 1mm)

These may not be perfect yet, and I’m keen for anyone’s feedback on what’s led to more successful prints with these soft filaments. The main thing we’ve noticed is that the soft filament is challenging for the extruder to push down into the nozzle and force out the tip – it is quite common for the nozzle to clog and filament to keep feeding through until it comes out the back of the extruder. Luckily nothing has jammed up yet, you can pull the filament back up out of the extruder and try again. With a bit of a search online, it seems that some 3D printable parts may solve this problem, in particular this modified Extruder Drive Block available on Thingiverse which closes the opening where the filament likes to escape, and will hopefully better force it down through the nozzle. The video below from Wanhao USA helps highlight the problem, and how this 3D printed part can fix it.

It’s early days with this filament, and I know the stock extruder of the Duplicator i3 is really not optimised for this type of material. But it can be done, and I’m sure with some tweaking can be made more reliable. Stay tuned as I am currently printing the new block to install on the Duplicator in the coming days, and will report back with results.

– Posted by James Novak