Initial Design Iterations
Architecture Design Decisions
This week, our team started off by facing a couple major design decisions in the overall structure of our yo-yo. We were happy with the lotus design as an inspiration but were ready to help the idea bloom into a beautiful and well-planned design.
Flower Placement and Proudness
The first item of discussion was how large and where we wanted the lotus to be. We wanted to explore many possible orientations to ensure that our team was picking our favorite layout out of all possible options. The initial design showed the flower sitting proud of the yo-yo cavity, having the lily pad approximately flush with the end of the the yo-yo body. Other options that we explored sheltered the lotus flower by harboring it inside the body or placing it on top of a pop-out lily pad.
Flower Sitting On Yo-Yo Body
This design would use a very shallow body piece that would keep the lily-pad still visible, while allowing the flower petals to make up most of the body and height of the yo-yo.
Flower Inside of Yo-Yo Body
This version shelters the lily flower more and gives off a more terrarium style. It makes it seem like the user is looking in on the lily rather than the lily jumping off the body of the yo-yo.
Flower On Pop-Up Lily Pad
In this design we tried to add more differences in dimension and texture to our different parts. We explored how the lily pad could integrate in a tighter way with a "water" snap ring to create a more 3D effect on the yo-yo's surface.
We believe that the Pop-Up Lily Pad design adds the most texture and displays the flower in the forefront without hiding the other elements from view.
Petal Designs
A challenge that our team quickly identified was forming the curved flower petals. In our experience, such curved and elegant forms are very hard to model. Annie and Kim tried out different modeling techniques in an attempt to find an injection molding-friendly, beautiful petal design.
Petal Design A
Kim's first attempt featured two nested rings of petals (seen to the right). The individual petals were modeled using splines, tapered symmetrical extrusions, and many fillets. The single modeled petal for each ring was repeated in a circular pattern. The stigma, seen in pink in the middle, was quickly modeled to be the approximate shape of a lotus stamen with extruded nubs on the top face. The method of attachment between the pink and yellow petal layers could be a snap-fit stamen, a snap-fit between the actual petal layers, or another snap-fit component.
Petal Design B
Annie attempted a different way of creating the ring of petals using Fusion 360's sculpt environment. One of aesthetic challenges of the petal components is to get them to have a smooth curvature, and the solid modeling features can leave a visible line while transitioning between fillets and faces. This is due to fillets having a G1 order of surface continuity (tangency), while splines can achieve G2 or higher orders of surface continuity.
Using a T-spline body, the petals were first reflected in a circular pattern, so any geometry adjustments could be applied to all petals at the same time. The second layer could be made in exactly the same way, just scaling the petals down. One layer is shown here for clarity. Some quick analysis tools were used to assess whether or not the smooth curvature was achieved. The Zebra Analysis shows there is good surface continuity (very few sharp edges) across the part, while the Curvature Analysis reveals that while the petals are smooth, they are not totally flat. This will be fixed in the next iteration.
Next Steps
Next steps are to combine learnings from both Petal Design A and B to create a final model of the two petal rings.
Lily Pad Design
There are many ways that we can incorporate a lily pad into our various potential architectures above. For the cases when the flower is actually recessed inside the yoyo body, the thermoformed lily pad wedge would need to be cut during the assembly process, which could lower overall efficiency (and morale). One way to tackle this issue is by letting the thermoformed lily pad sit under a snap ring to hold it in place and give the impression that it is floating in water!
Concept Ideas for Stigma and Stamen
Injection Molding
Advantages:
- Trough on stigma could be a good mounting location for any attachments and is hidden by lotus flower petals
Potential Difficulties:
- Stamen stems will be very thin and and would not be feasible to injection mold
- Too many parts
- Could lead to a lot of frustration during assembly
Laser Cutting Felt
Advantages:
- Easy to produce many parts at once
- relatively accurate and compressible pieces that can sit inside trough on stigma
Potential Difficulties:
- Requires fine tuning for laser cutter to prevent any charring along edges of felt
Potential Stamen Materials
The design of the stamen is currently still pretty open, and we can look into these materials to see which gives our yoyo the best aesthetic!
Felt
Fuzzy Yarn
Thin Feathers
Blog post written by Kim Veldee, Riley Davis, Annie Zhang, and Toria Yan