Up! Printer, Auto Feeder

The Up! printer uses a clever method to manage their filament. The filament passes through the feeder, through a rigid tube and then down into the print head.

As the print head consumes material, the length of filament between the feeder and the print head decreases. Eventually, this causes the rigid tube to press down on the feeder and the feeder happily advances the filament.

More on how it works after the jump!

Here's the circuit board side of the filament feeder. This is a super basic 555 timer chip. The micro switch activates the timer which in turns turns on the motor for a few seconds.

The motor is geared for torque. It runs on 5V and has a spur gear and idler setup similar to the print head design. The idler wheel is a cute, teeny tiny bearing fixed with a machine screw.

The little arm that triggers the micro-switch shows an excellent example of a live hinge/flexure. Any Up! operators can measure this part for a decent design reference for flexible pieces.