I have recently commissioned a printer with a dual bowden extruder arrangement. I am using these fittings that I have purchased from McMaster.

Twice now, I have left a print unattended only to come back to find that the tube has slipped out of the fitting at the extruder, and there is a pile of filament on the floor. Afterwards, the fitting no longer holds on to the tubing. I can insert it, but the fitting does not grip it.

Does anybody have any advice for what to do here, or perhaps might there be some alternative fittings I can use here.

Thanks

What retraction settings are you using? If this is too much, it could be causing the connectors to fail.

I am set for 5mm of retraction at 50mm/s with a 2mm minimum distance. I'm actually quite happy with the flow rates and I am getting very minimal stringing (actually almost none)

Edited 1 time(s). Last edit at 11/12/2015 10:44PM by jbernardis.

Those fittings are really designed for pressurized air and little to no movement. My dad uses them in classic cars with airbags (air shocks) and when they have 100psi in them you cannot pull them out. So, the air pressure keeps the gripping portion pushed outward preventing removal of the airline. How about forcing the plastic to stay out with a printed clip to fit between the metal body and the plastic rim? You could design it to be easy to remove (with a handle) and it might keep the line where it should be.

Also note that I have seen some of these that have a deeper push on them than it looks like on the one you posted. By that I mean that the plastic rim is further away from the metal boxy and thus it must move further to unlock the tube. Just a thought.

Quote
jbernardis
I have recently commissioned a printer with a dual bowden extruder arrangement. I am using these fittings that I have purchased from McMaster.

Twice now, I have left a print unattended only to come back to find that the tube has slipped out of the fitting at the extruder, and there is a pile of filament on the floor. Afterwards, the fitting no longer holds on to the tubing. I can insert it, but the fitting does not grip it.

Does anybody have any advice for what to do here, or perhaps might there be some alternative fittings I can use here.

Thanks

The ones that E3D supply are very good and have the advantage that they have a 4mm hole all the way thru so that the tube will pass through and get right upto the hobbed bolt Bowden coupler

They are manufactured in the UK by a company called JG Speedfit another one that is also highly recommended is the Norgren range such as Norgren adaptor

Don't know if these are available in the states but I believe that filastruder are distributers for the E3D stuff over there. see US Supplied E3D Bowden adaptors

HTH Doug

Thanks for the filastruder link. A $16 investment is inexpensive enough that I might give it a try before redesigning things.