The League Rulebook specifies a few constraints that drive base robot material selection:
- The base must be made from solid 1⁄2” HDPE
- The entire robot can weigh no more than 30lbs
The base MUST be HDPE, but the walls, lid, and other components can be a wide range of materials. A few additional things to consider might include:
- Durability: these robots take big hits. You want a material that won’t shatter, or deform terribly upon impact to protect the heart of your bot (expensive parts and batteries)
- Machinability: make sure the material you choose is compatible with the machines you have at your disposal. Some University CNC machines have restrictions on what materials they can cut for example.
- Signal Interference: In years past we have seen issues with aluminum walls creating a Faraday cage of sorts and interfering with controller signals. Use caution if you go this route.
For these reasons, as well as efficient use of purchased material (since you’re buying HDPE anyways) we designed the entire shell out of 21” HDPE. It’s easy to machine (and file/drill for modifications), it’s lightweight, durable upon impacts, and comes in many bright colors. Choose whichever you’d like.