Cardiac Patch Delivery Device
Cardiac Patch Delivery Device
Apple Yo-Yo Manufacturing
Introduction
In the course Design and Manufacturing II (2.008) at MIT, my team and I designed a yoyo and created a detailed manufacturing plan throughout the semester. The class looked at the processes and systems required to scale up to mass manufacturing products. We utilized the framework of Cost, Rate, Quality, Flexibility, and Sustainability to compare manufacturing process options, while focusing on the fundamental physics of each process. Unfortunately, our semester was impacted by the pandemic, and the class became virtual halfway through. Therefore, we were unable to manufacture one hundred yo-yos as we intended. However, we were able to utilize MoldFlow software to simulate injection molding our parts, which helped us estimate the shrinkage values of the parts and any potential defects.
Design Overview
After following the steps of the design process, we chose to create an apple yoyo with a spring-loaded worm. We went through multiple iterations of our design and used feedback from design reviews to determine our final yoyo shown on the right. For more details on the steps we followed during this process and iterations we went through, check out our team's blog here.
Our yoyo consists of five injection-molded parts (apple top, apple bottom, inner body, stem, and leaf), two thermoformed components (bite part, and washer to prevent worm pullout), one 3D printed component (worm), and several purchased parts (hex nuts, axle spacer, set screw, spring for the worm, and shims).
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The apple top part has several key features: a bite-mark hole that reveals the thermoform bite part, a slot in the center with a loose-fit on the stem and leaf, a vertical, tube-like channel for the worm, and a ledge for a snap-fit with the inner body (with the thermoformed part sandwiched between). Similarly, the apple bottom also has a ledge for a snap-fit with the inner body.
The inner body is designed with a raised slot for the worm spring to hook into. The hex nut and shim are insert molded into the inner body part. The leaf and stem have hook-like features so that the parts can sit between the apple top and the thermoform bite and be constrained from moving or rotating out of place. The worm will be attached to a spring with a washer that will prevent the worm from being pulled out.
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Perspective (left) and Cross-sectional (right) Views of Yoyo Assembly