Fab Lab CITC Alaska Machine Building 2016
Steven F
After much confusion and discussion we found our selves in agreement. We will build a breakfast robot! The purpose of this robot is to make us delicious foods in delicious shapes. Heart Shaped Sweet Bread. Robot Shaped EGGS. EGG Shaped Robot Sweet Cakes, the possibilities are endless.
Project Planning
Steven F
During our chat with our New Zealand instructors, we layed out our project flow. Sam and Kadin will focus on designing the extruder, While Ki and Steven focus on assembling the primitive gantry. Later on Mechanical responsibilities will fall on Sam and Steven, while Kadin and Ki will build and assemble the electrical and software portion of the machine.
Building the ToolHead
Sam G
Kadin and I talked about some different ideas for the type of extruder we would want to use with our design. After talking it out a bit, we decided to research the Moineau Pump. A Moineau Pump is a type of Progressing Cavity Pump. These pumps work by transferring a fluid by means of progress through cavities as the rotor is turned. The video below shows how a Moineau Pump works.These types of pumps are good because they do not cause pulsation as the liquid is moving out of the outlet causing a constant stream of fluid to be pushed through the system. However, the geometry behind these pumps are a little complicated and there seems to not be any good literature on how to design one. If we can figure out the geometry and get a working prototype we will most likely go with this type of pump. If we cannot, then we were also thinking of a pressure type system in which the system will be hooked up to an air compressor that changes the pressure within the hopper to allow the batter to come out.
Building the ToolHead
Kadin F
This week I designed an extruder prototype for our pancake printer using Solidworks. The design used two worms to create a dual extrusion mechanism that will be gravity fed. For my next iteration I am working on designing a progressive cavity pump for more accurate and reliable extrusion. Files can be found here (Link)
Gesalt Boards
Ki F
The gestalt nodes are small, chainable circuit boards that control stepper motors for machine control. They communicate with the computer through RS485 through an FTDI cable. To connect the nodes to your computer, you need to mill a circuit board that will convert from the FTDI cable to a 10 pin header. After milling the board and soldering the components, connect the board to power, make a 10 wire cable (or several) and plug it into the milled board, remembering which wire is connected to which pin. Remembering which pin is connected to which wire, connect the wire from the milled board to the 10 pin header closest to the silk screened "gestalt node." Typically the cable would run across the board, unless you designed your cable with this in mind. To chain nodes, connect another cable to the other header, once again checking the pin orientation. You can now plug your stepper motor into the 4 pin connector on the board.
Assembling the Gantry
We chose to use the files designed for the Half inch HDPE and use Sintra as it is a more accessible building material. Sintra is typically a foam PVC. Gantry files can be found here (Link)
Assembling the Gantry Pt 2
We assembled 3 of the "stages" milled from Sintra.
Sam G. builds the stages.
3 stages fastened together. Our platform is PCB and an aluminium plate double sided taped to a chunk of wood we were hoping this would absorb and dissipate most of the heat from the electric skillet.
Assembling the Extruder. The Extruder designed by Kadin F. had some issues. So we 3D printed a pump from "The Internet(Link)" while he works out the kinks.
I apologise for the potatoe image of our Extruder/Pump
Larry W. assists with the electronics.
Sam G. aligns the extruder assembly.
Making pancakes.