FFCP 2016 Ninja Flex feeding issues. I need advice please.

[huntleybill]

I am having issues getting ninja flex to feed. Semi-Flex is a little better but not much. When I load the filament it seems (at least to me) that it extrudes slower than than ABS or PLA does. I took a video of it so you can see if I am nuts or not. The hotend temp is set to 230. I tried this thingiverse mod but it did not work for me. http://www.thingiverse.com/thing:857200

My question is: what can I do to get this to print flexible filaments reliably ? What do you do to run flexible filaments? I bought this printer because it advertised that it can run flexible filaments. I contacted Mr. Tang but he said he does not use flexible filaments.

https://youtu.be/ie5DEcihR9k
https://youtu.be/hPTtZ8q1BcE

[curious aardvark]

okay you've got two options.
Modify your extruder or switch to polyflex.

The only colour of ninjaflex that will reliably print on an unmodified mk8 extruder is green. Nothing else I've tried will work.

Polyflex is the best flexible filament for printability.

The best rubber filament I've used is flexismart.

For any flexible filament you need to reduce the print speed to a MAXIMUM of 30mm/s (ignore what it says on the packet if it says you can print up to 50mm/s) And run it at the top end of the recommended print temperature. Loading can be an issue as it loads much faster than it will print at.

The trick is to stop the load as soon as you see the filament come through the nozzle.
Sometimes I find I have to unload and reload a couple of times to get it setup properly.

Polyflex, just works. But is a flexible plastic (pla) NOT a rubber based filament

The most reliable tpu (rubber based) flexible filament I've used is flexismart. Runs at 210 and 30mm/s without any problems.
I'm just about to order some more, which will be the first time I've found a rubber filament reliable enough to actually use a whole roll up !
It's not quite a s strong as ninjaflex - but it's a helluva lot more user friendly.

Sebastien has used a fariyl simple modification on his printer and reckons it prints ninjaflex really well now.
Used one of the little plastic ptfe tubes that sits inside the heater block. You insert it between the top feed hole oin the extruder and the feed hole for the heater. carefully cut out the section by the feeder/hobbed bolt so the teeh can still engage the filament and the tube doesn't get caught by the teeth.
Essentially it stops the filament from flexing and getting wrapped round the hobbed bolt and redirects it straight to the heater block.

Simple and ingenious :-)

[Sebastian Finke]

Sebastien has used a fariyl simple modification on his printer and reckons it prints ninjaflex really well now.
Used one of the little plastic ptfe tubes that sits inside the heater block. You insert it between the top feed hole oin the extruder and the feed hole for the heater. carefully cut out the section by the feeder/hobbed bolt so the teeh can still engage the filament and the tube doesn't get caught by the teeth.
Essentially it stops the filament from flexing and getting wrapped round the hobbed bolt and redirects it straight to the heater block.

Simple and ingenious :-)

That's exactly what I did. Takes all of 2 minutes to drill and fit the tube. Now I can print ninjaflex and other tpu's easy peasy.

[Sebastian Finke]

Another thing (CA already knows this but I'll say it for the benefit of those that don't):

We often speak here about rubber filaments. This however is incorrect as rubber is not a thermoplast and cannot be printed. So when we say rubber we really mean rubber-like. Generally tpe/tpu.

'Cos someone's gotta cross the t's and dot the i's...

[huntleybill]

Do you have a link to this Sebastien and his tube?

[curious aardvark]

that's one of the things I really like about flexismart. It actually behaves and feels like proper rubber.

Industrial rubber and the sap from the rubber tree - totally different things :-)

[QUOTETakes all of 2 minutes to drill ][/QUOTE]
what did you drill ?

[huntleybill]

Where do you get flexismart at?

[Sebastian Finke]

what did you drill ?

1) Remove extruder
2) Notice the entry and exit holes for the filament in the black housing aroung the extruder gear. The exit hole must be drilled open from 2mm to 4mm.
3) Get some PTFE tube like used in the hot block. Cut one end to fit snugly against the gear. The other (flat) end must fit snugly against the entrance hole on the hot block.
4) Reassemble everything.

This is a simple mod that allows you to print flexible materials without them wrapping around the extruder gear.

[huntleybill]

Sebastian: Do you have a picture of what the PTFE tube looks like after it has been installed? I was wondering if you shaped the end of the tube to fit the contour of the hobbed gear?

[curious aardvark]

flexismart I get from amazon.co.uk

As for sebastien LOOK UP ^^^^^^^ 4 posts