Moves filament feeder above the printer to shorten and straighten the bowden tube

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Attribution

I wanted to be able to use flexable 1.75 filament on my Ultimaker 2 ex

Description

In combination with changing my Ultimaker 2 extended to use 1.75 mm filament I added this feature so it would successfully print flexible filament (TPU). The original setup from Ultimaker presented too much Bowden tube with a curve and this would make flexible filament to compress and create too much friction to pass successfully through to the print head. In addition the feeder design would allow the soft filament to buckle just above the pinch bearing and jam. The feeder provided here has zero open space to allow this problem. As seen in the OpenSCAD drawing a spring supports the stepper and feeder above the printer.

I have this setup on two Ultimaker 2 printers I use. It has worked well with both inexpensive TPU and ABS filaments for over 1800 hours of printing.

Materials and methods

Modifications were made to the entire pathway of the printer to accommodate 1.75 mm filament.

The overhead spring was hung from an upper wire shelf of my workstation.

The feeder uses the same bearing and spring as the original Ultimaker 2 feeder. I also added a compression type tubing connector to the feeder end.

The printer end of the short Bowden is sleved by a piece of 4mm ID Teflon tubing and pinned in such a way that the pin does not go through the lumen of the 2mm ID tubing.

The axle for the filament management pulley is a short piece of 2mm ID Teflon tubing

Wiring is done using a couple of plugs and a jack placing a plug on the old stepper motor and the overhead stepper motor and a jack on the back of the Ultimaker 2. This allows me to use either filament feeder although I rarely use the feeder on the back any more.