Injection Molded Yo-yo
ENGS 146: Computer Aided Mechanical Design
May 2018
Objectives: Design and Manufacture an injection molded yo-yo in Thayer School's Machine Shop.
Skills:
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Solidworks Mold Design
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Injection Molding
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CAM Tooling Setup and Machining
The Design.
The Project.
Early in ENGS 146 I was tasked with designing and manufacturing a yo-yo suitable for easy injection molding. Considering the center of gravity, moment of inertia about each axis, and yo-yo performance I came up with the design at right. I created a mesh of 5 Fibonacci spirals curving clockwise, and 8 Fibonacci spirals curving counter-clockwise. When spun, the yo-yo's sections appear to "grow". Draft angles and thermal deformation conditions were applied throughout the design process.
Manufacture.
I created a two part mold using SolidWorks' mold tools and incorporated ball bearings set into spherical pockets as alignment pins. I used HSMworks, a Solidworks CAM plug-in to create 3-D toolpaths, as shown in simulation at right. I used CNC Prototrak Mills to machine the mold halves. Finally, the mold was injected with ABS plastic using a Morgan Press Model G - 55T desktop injection molding press.
CAD Model
Manufactured Yoyo
Yo-yo
Finished Product:
