| s1900ahon |
14-01-2013 11:07 |
Re: ideas for a strong hook
For Breakaway, our team fabricated a hook out of carbon fiber. It wasn't used in competition, as we followed our normal path of late mechanical construction and the winch mechanism was never integrated on the robot. It continues to be the object of strength testing to this day.
It was moderately simple to make (compared to the rest of the Breakaway robot that also used significant CF components). The mold was made by gluing+screwing a couple of 2x4 pieces together, and cutting out the hook shape on the bandsaw. After sanding and sealing with epoxy, we polished and waxed the surface, and then used PVA for a mold release. The hook layup was done with a wet process: 3 layers of 3K 2x2 twill CF, one layer of segmented 0.25" Nomex honeycomb, and 3 more layers of CF. Wrapped in a vacuum bag and left overnight. The whole thing took about 4 days in total to fabricate (3 for the mold making, and 1 for the layup).
Having described this, I believe the team will use a conventional, non-locking hook this year fabricated from aluminum. CF is a fun material to work with, but you have to be particularly careful of post-layup machining as the dust becomes hazardous.
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