Ninjaflex, underextrusion, printing very unreliable

[skewcrap 3]

Hi

 

I'm struggling printing Ninjaflex with my Ultimaker Original. I tried printing with the following settings:

Nozzle: 0.4mm (3dsolex)

Print speed: I tried 10 - 30 mm/s

Temp: I tried 230-250°C

Bed: 50 °C

Layer height: I tried 0.15 and 0.1mm

I tried with different values for flow and filament diameter, seems to have no impact at all.

 

I often have underextrusion, especially in the infill. At the moment I try printing a cylinder with D=20mm, H=20mm, so basically a really easy geometry. I print with 100% infill, but it ends being rather 40% because of underextrusion. The walls seem quite ok, but the infill is crap. I have a bondtech extruder and normally I don't have any issues with extrusion.

 

I already changed all wear parts of the print head including the nozzle and the teflon part.

 

Could it be bad material? The ninjaflex is approximately 2 years old.

Do I have to try a larger nozzle?

I don't know what else might be the issue.

 

Any help would be highly appreciated.

 

Regards

 

 

 

 

Edited April 1, 2018 by skewcrap

[mastory 44]

No experience with Ninjaflex.  Assuming the printer is printing OK with more standard filaments, I would alter settings that would promote easier material flow.  Maybe a bit hotter yet, or taller layers.  Flexible materials are not really considered reliable for bowden printing, so I wouldn't get my hopes too high regarding the expected results.

[skewcrap 3]

Ok, i will give it a try with an even higher temp and layer height 0.2mm. When I tried printing ninjaflex the first time 2 years a go, I just wanted to try. The results were pretty good, which of course increased the expectations.

 

What I just don't understand is that the walls basically don't suffer from underextrusion but primarily the infill.

 

Quote

Flexible materials are not really considered reliable for bowden printing, so I wouldn't get my hopes too high regarding the expected results.

 

So, how do you print flex material reliable?

[peggyb 171]

a bit of light oil on your filament helps to get it trough the Bowden as ninjaflex it quit 'sticky', not too much.

and check your infill speed settings, they are usually faster than the wall settings, make them the same, like you said the walls are ok.

and, if possible, no retraction.

[skewcrap 3]

Retraction is off, infill speed is the same as the walls. When I try the oil, isn't it bad when I print PLA again? Maybe silicon spray would be a better option?

[peggyb 171]

the oil will burn when extruding, use just a very thin film on your filament. A bit on a (paper)towel or finger and and softly rub the filament before it enters the extruder.

[mastory 44]

You might be experiencing a difference in the infill due to the slicer.  As I recall, a few slicer versions ago, infill behavior changed to be more sparse.  I don't remember if was grid or line infill that began to act differently causing much more sparse behavior.  Possibly try a different infill style depending on what you are currently using.

[skewcrap 3]

Lubicration of the filament did the trick! Thanks for this hint. It's printing just fine now!