Choppa Plastic Antweight Combat Robot

At my first combat robot event, my mentor to the sport gave me a version of a bot called LifeSteal from Thingiverse which he had renamed “Get To The Choppa.”

I took that original model and idea and have been iterating on the design as I teach myself more and more about combat robotics. 

This design has been redone in CAD from the ground up to support a few new features: 
1. Motor mounts imported from Just Cuz Robotics to support their dartbox motors and made part of chassis print
2. Channel for weapon motor wires to help protect the goods
3. Filleted edges for enhanced strength
4. Wedged shoulder area on chassis
5. Weapon geometry redesigned for 2826 motors

While the new weapon geometry was fun, I recognize it's not the most effective. There is some bite added beyond the OD circle but not enough to be truly damaging. It was mostly a tool for learning CAD and it looks awesome so I used it. 

For drive motors, I have used both Gecko and Viper motors from Just Cuz Robotics with great success. I used Pololu's universal hub and 60×8mm wheels. 

Weapon motor was a Turnigy D2826 but the mount holes should support most brushless motors, you would just have to update the weapon geometry to match. 

In order to make weight, I had to print the chassis at 50% infill and use a slicing trick to make the bottom of just the enclosure area to use gyroid infill only for a kind of mesh bottom that saved me about 10g. I did the same trick for the entire top lid. 

The weapon was printed at 100% infill for maximum strength and power. If you use a different weapon geometry, there's a good chance you could print a stronger body. This chassis cracked when it got hit by a particularly mean barrel spinner named Hedonism Bot. 

This design has been redone in CAD from the ground up to support a few new features: 
1. Motor mounts imported from Just Cuz Robotics to support their dartbox motors and made part of chassis print
2. Chassis made bigger in x and y to support bigger motors
2. Channel for weapon motor wires to help protect the goods
3. Filleted edges for enhanced strength
4. Wedged shoulder area on chassis
5. Weapon geometry redesigned for 2826 motors