In my junior fall semester I took MIT's 2.008: Design for Manufacturing II, in which we learned the ins and outs of mass manufacturing and DFM techniques. Our final project required us to mass produce 50 yo-yos.
Our team of 6 students (Team Yolette) opted to design a Roulette inspired yo-yo, complete with a central brass nut, wooden and gold finish, and a steel ball bearing. We used thermoforming, injection molding and CNC tooling (for molds) to produce our parts.
From this class I learnt about early prototyping techniques, draft angles, injection molding, and a great deal more about DFM.
Our design consisted of several injection molded parts: a body, retaining ring, and a coloured insert. It also had a thermoformed cover and two off the shelf metal components, a central brass nut and steel ball bearing.
The most challenging component was the coloured insert: our mentor Mr Dave Dow told us to go down the path less travelled (less travelled as it was far more difficult) of double shots; the final insert was composed of a red and black IM component fitted together and then injection molded on top. A long and difficult process, we overcame warping, massive shrinking and other obstacles using some unconventional methods (ice baths and kettles) and learnt a lot about DFM in the process.
Our journey is detailed in our blogspot: http://yolette-yoyo.blogspot.com/
After lengthy ideation, we settled on a roulette themed yoyo. ( other ideas were aircraft propellers, flaming flints, expanding tongues...).
Ideation
Chef Jose preparing the red and black interlocking rings to be laden (overshot) with gold.
The team!