Overall, we believe that we were able to make a good and reliable yoyo. In terms of aesthetics, we achieve our main general purpose which was for it to look as similar as possible to a Hydroflask. However, we noticed that there are three main areas of improvement:
1. Add the iconic black cap that would snap fit to the metal ring. We actually made the mold for this and tried to injection mold it but we ran into the issue that the ejector pins were puncturing the plastic. A possible solution for this would have been to make more holes in order to have more ejector pins and locate them closer to the outer circumference of the cap (since the main issue seemed to be that the plastic was getting stuck in the mold) but due to the pandemic we had to leave early and so we couldn’t find time to remake the entire mold.
2. The bottom of the bottom part of the yoyo was slightly uncentered. It was not a major issue for balance of the yoyo, but it still affected the general aesthetic of the final product. Hence, a future improvement would be to remachine the mold of this part, making sure that the core and cavity are perfectly aligned and that the bottom of the bottom part is centered with the top of the bottom one.
3. Since our yoyos are not symmetric about the mid plane, it is very slightly unbalanced. It is hard to notice this if you only yoyo it once but after throwing it up and down several times non-stop, you can tell that the yoyo tips off to one side (the bottom part: the heavier one). To fix this, we might need to add some weights or maybe increase the thickness of one of the components of the top half of the yoyo in order to increase the overall weight of this half.
The Hydroyo design is simple enough to easily mass produce it. In fact, we could even add some more personalization quite easily, by using different colors for the body of the yoyo (which is currently a pastel light-blue). Dimensions of the CAD drawings are clear and the tolerances of the press and snap fits seem to work really well. When assembling the yoyos we didn’t see any problems and in fact after some drop tests we realized that it was very hard for our yoyo to come apart. Perhaps the press fit of the bottom half of the yoyo is a little bit more on the loose side than the one of the metal ring with the other part, but it still works really well. Overall, we believe that we were able to make a well structured yoyo that is not only sturdy but also looks good and is fun to play with which was our ultimate goal.
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