We completed production runs this week and finished our 50 sushi yoyos! This included:
Here are our final yoyos: Here are the final die for thermoforming and molds used for injection molding: Thank you for following our progress throughout the semester!
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Over the past 2 weeks we worked on optimizing our snapring and starting production runs. Here is some of the progress we have made:
We tested each of our molds and ran into issues with fitting each component within each other. The injection molded parts eventually fit together after some re-machining but the thermoformed rice part did not fit well within the seaweed part, so we had to alter the molds for injection molded parts to accommodate this. After several iterations, here are our molds and tested parts: We altered the dimensions of the rice die a couple times to allow for a better fit and easier stamping of the inner hole and outer diameter. Our yoyo assembled together looks like this: *These are not the final colors we will be using - the parts are just tested in these colors* Attempts and issues over the past 2 weeks:
We completed the salmon, snapring and seaweed molds this week and re-machined parts of the avocado mold so that the core and cavity fit together well. Here are the final molds:We also tested each mold via injection molding:We remade our rice die so that it is easier to stamp out the center ring to leave space for the ingredients.- We machined the core and the cavity of the seaweed mold. - We are planning to drill the .25" hole for the cavity today. - Seaweed core and cavity - We made the height of the yoyo shorter, the salmon fully circluar, made the avocado sit on the salmon, and removed the middle ribs. - Avocado core and cavity Salmon Core and Cavity Snapring Core and Cavity
Based on the feedback we received at the Design Review, we made several changes to our design: - We decided to thermoform the rice. We will glue real (dry) rice to our thermoform mold to create a rice mold with an extremely realistic texture. This will increase the quality of our yo-yos. - For our injection molded parts, we have decided on: 1. Outer shell (Seaweed) 2. Ingredient 1 (Salmon) 3. Ingredient 2 (Avocado) 4. Snap ring - For the seaweed outer shell, we decided to not have a draft angle for the outside because we just need a draft angle for the inside. This will also help the roll look even more realistic. - To texture the seaweed mold, we plan to manually sand and/or sandblast the mold after it is milled. The plastic will shrink enough that the minuscule indentations will not prevent the part from releasing from the mold. - We will incorporate a small snap ring to hold the rice and ingredients in place. The snap ring will be the color of the seaweed, giving a more realistic dimension to the seaweed layer of the roll. -The inside of the seaweed shell has ribs and posts to support the ingredients. We ditched the separate support piece inside, and incorporated everything into one part. - We decided to make two "interlocking" ingredients that will sit together underneath the thermoformed rice, more closely imitating our inspiration image of a salmon-avocado roll. The ingredients will form a circular shape together, which will fit through a hole cut in the thermoformed rice. Rendering of Final Design CAD Models of Individual Components Section View Mold of Most Complicated Part (Seaweed)
Once we decided we were set on a sushi roll, we needed to figure out how we were going to actually fill the requirements of the yo-yo. We needed 3 injection molded parts, 1 thermoformed parts, and 1 snap fit. In lab, we talked about our design together, writing our ideas on a whiteboard and observing other yo-yos to generate some ideas. We wanted to do: Thermoformed Part: 1. Ingredient Injection Molded Part: 1. Seaweed 2. Rice 3. Snap ring Snapfit with snapring and seaweed. We were inspired by this yoyo to create our initial design: We met again to make our ideas a little bit more concrete and figure out how to actually the design and manufacture the yoyo. We started out by figuring out how we were actually going to manufacture the pieces and how we were going to split up the work between all of us. We realized we wanted to keep our seaweed a constant thickness for injection molding, so we decided to make it two parts. We decided to get rid of the snap ring and use a snap fit on the rice-seaweed interface now. So our three injection molded pieces are now: 1. Rice 2. Seaweed 3. Inner casing Thermoformed parts: 1. Ingredients Snap fit: 1. Rice-seaweed Once we decided all the dimensions, we created a preliminary drawing and split up the CAD work to make our assembly. Manufacturing Processes: We plan to injection mold the rice, and we think our biggest difficulty will be achieving the correct texture. Additional machining could be done for the part to be more realistic. Machining for our current rice design might not be feasible as the spacing between the grains is too small. We might need to use a smaller tool. The raised heights of the grains and the differing thickness of the part towards the center (where the ingredient is inserted) could create an issue due to uneven thicknesses. The outer shell and inner platform have simple enough geometries that we don't expect to encounter any difficulties while injection molding as long as we use draft angles in our molds. A potential problem could be the spacing between the two parts. For the ingredient, we intend to thermoform it. The geometry of the part is also simplistic; however, creating a consistent thickness throughout the part may be difficult, especially at the edges. Assembly: Materials Needed: paper for printed ingredient plastic (ABS?) yo-yo axle set screw (10-24, 5/8") axle spacer 10-24 hex nut CAD Models: Mold designs (cavity and core):
We first created a google document with everyone just writing down their ideas, starring the ones we liked: Ben 10 *** Sushi roll*** Captain America shield Spider-Man Iron Man arc reactor Simon says (the 4 color game) Spongebob Starbucks logo*** Ball maze Macaron *** Spinner Oreo Pepsi logo Pie* Pizza Cupcake Watermelon* Cookie * Donut* Hamburger Avocado* Fried egg Beach ball *** Button Moon Lady bug Something cross stitched Kirby ** Snail* Storm drain with ninja turtle under it * We then narrowed to six choices: - Ben 10 - Sushi roll - Macaron - Beach ball - Starbucks - Kirby Everyone sketched these ideas so we can visualize it: Ben 10 YoYo Sushi YoYo Macaron YoYo Beach Ball YoYo Starbucks YoYo Kirby YoYo We then voted on which idea we liked the best, and it was: SUSHI!! We googled pictures of sushi and found this image to be our inspiration. Top view of our Sushi Yo-Yo Side view of our Sushi Yo-Yo Manufacturing Process Ideas:
- The seaweed and inner ingredients(avocados, cucumbers, salmon, etc..) can be injection molded. - The rice can be thermoformed. - The rice will snap - fit into the seaweed. From left to right: Minsu Jung, Alejandra Navarro, Melissa Klein, Danielle Gleason, Cole Linnus, Abdalla Osman Minsu - I'm a course 2 Junior interested in the aerospace industry. Outside of class, I'm building a solar car and it's absorbing all my free time T_T.
Alejandra - I'm a course 2 junior interested in robotics and autonomy. Catch me either running or drinking yet another cold brew in my down time. Melissa - I'm a mechanical engineering and music double major who loves coffee and boba a little too much. Danielle - I'm a Course 2A senior concentrating in global development. In my free time, I'm either learning ukelele or cooking fancy food. Cole - I'm a mechE junior interested in rapid prototyping and design. I love going to concerts and playing volleyball in my free time. Abdalla - I'm a junior in course 2 interested in design and culture (and how culture influences design). I'm a member of the solar car team and spend all my free time with Minsu. |
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