How to get ninjaflex to feed into the extruder?

[Kent Hartland @heartlander My Robox is a Blue Commercial Version Kansas City, Missouri, USA]

The extruder sensor feels the filament and starts running the extruder motor but now matter how I “push” the filament, it will not pull on into the machine. I do have the new flex filament extruder and I have tried both NinjaFlex Semi-Rigid and Flexible PLA but neither will go in.

Kent
Damn Solid Design

[hagster @hagster My Robox is a Blue Commercial Version UK]

You might be doing thos already, but I heard that CEL were using a section of ptfe tube to constrain the filament ad it goes up to the exrtruder.

[Terry Taylor @n6mon My Robox is a Green Kickstarter Early Bird San Lorenzo, Ca, USA]

@hagster, is this use of a piece of ptfe tube documented anywhere?

Terry Taylor

[hagster @hagster My Robox is a Blue Commercial Version UK]

It was a recomendation from Pete. See here http://www.cel-robox.com/forums/topic/starter-profile-for-ninjaflex/#post-27144

[click @click My Robox is a Green Kickstarter Limited Edition]

Also, from empirical experience - that is the way to do it. And as tube goes only up to extruder through feed channel (if that far) and I cannot see this doing any harm to the printer.

[Dr. Woo @dr-woo I have several Robox units Kickstarter and Commercial Frankfurt/Main, Germany]

I also had problems feeding flex filament some time ago and opened a ticket back then. The official response is indeed to narrow the filament feed guides using PTFE tube with 3mm outer diameter. Lengths are 190 mm for Extruder 1 and 130 mm for Extruder 2. You may want to trim them slightly shorter to make it easier to feed the filament.

[Terry Taylor @n6mon My Robox is a Green Kickstarter Early Bird San Lorenzo, Ca, USA]

OK, it looks like my followup post did not make it. The issue that Kent and I had is that we were able to get the filament to feed all the way up to the print head, but the filament would NOT enter the hot section of the print head, it would just bunch up in the Bowden tube.

Terry Taylor

[BHudson @bhudson I have several Robox units Kickstarter and Commercial Arizona, USA]

I have found that if you cut the end of flexible filament square, it will sometimes not get fed through the extruder feed wheels and can sometimes catch if your Bowden tube isn’t fully installed.

1. Check that your Bowden tube is fully installed - insert a section of PLA into the Bowden tube from the head carrier end to support the Bowden tube while you are installing it. Wrap the Bowden tube in a single thickness of clean t-shirt. Pinch the wrapped section of the Bowden tube and T-shirt with thumb and finger within 1 inch of the fitting and press the Bowden tube into the fitting. This will allow you to increase the insertion force and ensure that you get a solid fit into the fitting.
2. Cut your flexible filament at a 30-45 degree angle to see if this will help solve the issue.

I operate two Betas and one Production Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

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