Friday, June 20, 2014

Friday Work Day

Hey you WOOFers! Don't forget about our Friday work days! Brandon Bowman will be in the room from noon onwards, so come on down, and check out the progress on Big Red!

See you there!

Thursday, June 12, 2014

Big Red's Hot End

As the Seafair Milk Carton Derby approaches, work on Big Red is accelerating. Seafair's Milk Carton Derby is an event we participate in every year to highlight some of the potential benefits of additive manufacturing/3D printing. Participants in the derby traditionally collect used milk jugs or cartons and use them as flotation for rafts or boats. For the last two years, WOOF has participated by collecting milk jugs, grinding them up and using them as raw materials for 3D printing a boat on Big Red, our largest 3D printer.

I'd like to present different aspects of Big Red as the event approaches. Today, we'll take a look at the hot end/extruder. This is a great improvement over last years design in functionality and ease of use. First, the basics of the extruder:
The motor on the end is a 12V wiper motor, which spins an auger inside the steel pipe, driving the plastic down to the end of the extruder.
The heating element is wrapped around an aluminum pipe, with some insulation and another aluminum pipe on the outside.

The most significant improvement so far has been the modular heating assembly that we can pull off easily when changing which recycled material we will be printing with. We use the same heating element for PLA (compostable silverware) or HDPE (milk jugs), but switch out the steel pipe and auger.
The extruder tip is simply a pipe cap that we drilled a hole in. Actual hole size may vary.
And that's the hot end/extruder fully assembled.