Project Statement
In this project, my objective was to merge a motor and mechanics to craft a playful art piece, an automata. My automata theme was drawn by the inspiration of the Mid-Autumn Festival, which had recently happened on September 29th, 2023. I chose to feature the Moon Rabbit and integrate it with the moon and the mooncake into my design, creating a interesting and thematic piece. This project is not only allowing me to bring the theoretical knowledge of mechanisms into real application, I also have practiced a lot on different fabrication techniques. Additionally, the project showed the importance of project/time management.
To bring my vision to life, I decided to use pinwheel gears and a cam mechanism, allowing the moon rabbit to move on the moon-like surface in a circular dance, while the moon cake moving rise and fall at the center. The two mechanisms were driven by a single motorized shaft. While the common sense of using teeth gears in automata. I decided to experiment with another type of rotating gear set. However, later on the test & trails, I found out it was a bit challenge in fabricating a functional set, which proven to be a valuable experience. Instead of 3D printing another set of gears to control the motor speed, I figured out that adding a PWM would work. Additionally, it also giving the freedom of adjusting the speed for entertainment purpose. Taking into account the size requirement of the automata, 8''x8'' to 10''x10'', I determined that an base to be 8'' to 8'' would be suitable after I CAD out the automata with all the components in Soildwork. The characters in my automata, the rabbit and mooncake, were handcrafted. They adhered to the project requirement and do not require the accuracy dimensions like the mechanism parts. More importantly, these pieces were crafted with my artistic expression and connection to the Mid-Autumn Festival.
Initial Sketches
My initial sketch was to design the mechanism of my automata. I sketched out the pinwheel and along with the cam mechanism in the center axial in the picture below. With the initial sketch, I could further elaborated the components and manufacturing steps I needed for the automata.
The picture below was a more detailed sketch of the characters and their motion paths above the automata box. The sketch includes a outline of components and dimensions that might need different digital manufacturing techniques to fabricate.
Inspiration: Mid Autumn Festival
The Mid- Autumn Festival, celebrated on September 29th 2023, aligned closely with the project posted date. So I was decided to choose a theme related to the festival. I chose the iconic symbols like the Moon rabbit, the moon itself, and the mooncake. The festival is celebrated on the 15th day of the 8th month of the Chinese lunisolar year. This is a full moon day, symbolizing reunion where families gather together to celebrate in chinese culture. The roundness of the full moon creates the sense of harmony and togetherness. According to the mythology, the jade rabbit is the companion to Chang'e, the moon goddness, living on the moon. Additionally, the mooncake is a round pastries filled with sweet filling, a traditional food in the festival. Its shape and color symbolizes the completeness of the moon and reunion of family.
After an exploration of various mechanisms, I settled on the pinwheel gears and cams, using these mechanism to show a vivid figure of the rabbit and its association with the moon/mooncake.
* Also, I am particularly fascinated with rabbit figure since I was born in the Chinese zodiac rabbit year :)
Work In Progress
With the initial sketched, I began my journey of CAD design for a week....
Base Size: Based on the project requirement of the size of the automata, I designed my box to be 8'' x 8'', where the side and bottom frames used the 0.7'' thickness wood and the top frame used the 1/8'' thickness wood plate done by laser cutting.
Mechanisms: This progress was a bit challenges. I was inspired to the video below of the pinwheel mechanism and its character circular motion.
Planning to let my character(rabbit) to move circular motion on top of the base was tricky since the character was not rotating in the center of the pinwheel as the usual pinwheel automata mechanism. Additionally, I planned to add a CAM in the center, moving up and down motion. I have discussed with Alyssa and Abhishek about the different ideas of how to integrating these two mechanisms into my automata.
The final idea was to design a pinwheel that its center has cylindrical shell going through the top base frame. An additional circular plate would attach on its cylindrical outer shell and the inner shell with fit with a bearing, allowing the cam to move another character in up/down motion in the middle of the bearing without interference with the rotating plate. Below shows a cad demo of my automata.
Components Preparation:
Shaft: 1/4'' wood dowel bought in Home Depot
Motor, motor mount: provided by class
PWM for motor, bearings: amazon
Pinwheels, cam, circular plate: 3D printed in Makerspace
Characters: Made by hand -- Polymer Clay
Test & Trails
With all component dimensions ready in CAD, I started to 3D print the pinwheels and cam components. Problems began merging with my 3d printed components: low filament, incorrect tolerance, component wall thickness was too small, etc. So I made couple adjustments of my CAD model and reprinted the parts.
Later, I figured out that Even with the 100% filament 3D printed pinwheel, the pin rods broke. So I changed the pin rod into 1/16'' steel rod instead to make the piece stronger.
One of the challenging part was to design the motor dowel coupler. My initial design was to 3D print a part that designed as 2 cylindrical shell where one would fit the dimension of the dowel and the one would fit the motor shaft dimension. In order to lock the motor with the 3D print part, I also design a slot for a rectangular key which could slot between the motor shaft flat surface and the inner wall of the 3D printed part.
However, the cylindrical shell thickness was too small, causing easy breakage. So I had to modify a couple time to adjust the design and also consume time to find an alternative way for coupling. The final version was made by thickening both cylindrical shells.
Integrating
Putting all the components together, the final work is here!
My automata:
Made by hand:
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