Having always fidgeted with pencils as a kid (and adult), I designed an injection molded pencil grip with wheels that can turn any pencil into a car.
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The final project for ME 325: Making Multiples was to design an injection molded product with multiple connecting parts. I love fidgeting with pencils and often would imagine them as cars while sliding them around. To turn that imaginative play into reality, I decided to make a grip that would make the pencils roll fluidly.
The final pencil racer consists of 3 unique molded parts: a central ring with axles on either side made from polypropylene (PP), a grippy piece made from Versaflex (relatively soft TPE) overmolded on top of the central ring, and two wheels (PP). I used Fusion 360 to make the CAD / CAM before machining the molds out of aluminum blocks on a Haas VF2 CNC Mill.
On the PRL’s Arburg injection molding machine, I shot all 3 parts. The central ring and the grip overmold required inserts to form the central hole and hexagonal shape, respectively. Finally, I turned a heat stake on the lathe and used it to lock a wheel onto each axle.
