The first full size mold that I created or this was the front leg mold. The cavity and walls of the mold are 3D printed. These were 3D printed to easily reproduce the target surfaces and were far cheaper than a silicon mold negative. Additionally, with a 3D printed mold excess material that would be wasted filling the volume up to the arm can be eliminated. This mold is split into 5 pieces that are held together with laser cut wood and plastite screws threaded into the plastic. The front legs require about 1kg of filament and 12oz of Flex Foam Mix. I calculated a 25% over pour for the molds to ensure that the foam would fill the cavity under non-ideal conditions. The top of the mold had vent holes so once the mold was at capacity the excess material would't damage the frog leg. One particular challenge that I encountered was hat the reaction was exothermic. If the temperature in any given area of the mold was too high the reaction would break down and the foam would not expand. To deal with this we agitated the mold to prevent the mix from building up in and one area.

The back leg mold was constructed in the same manner as the front leg mold but dealing with heat buildup was a great challenge. Just the footprint of this mold was greater than two times the size of the front leg. It required a 28oz mix of foam and had two entry locations to prevent the buildup of foam generating too much heat. This mold also had additional venting throughout each section of the mold since the volume was too great to push all of the excess out the top of the mold. The back legs were reproduced the least at Battlebots and generally survived the matches with only minor chunks removed. To fix gaps the remaining leg could be placed into the mold and then new foam could be molded onto the old.

The Frog head mold posed a unique challenge due to the shear size of the mold and desired surface finish for television. Each 3D printed section, shown by the colors on the color in the image to the left is roughly 11"x11"x9", allowing them to fit on the biggest printer we had available, the Lulsbot Taz 6. There is two plywood panels that hold the pieces in place, one on the bottom and then one on the top (not visible). Despite the use of mold release we struggles to eliminate linking lines and prevent tearing of the top surface when removing from the mold. With sanding and plastic welding the seams of the mold together we were able to get improved surfaces and each head continued to come out better than the last.

These parts mated the Apex gearbox to the Mag Motor S28-F4-150X. I manufactured these on a HAAS VM-2 and programmed the machine to find each part so I did not have to manually probe each part. Additionally I engraved each part so any team member could take apart the assembly and easily reassemble.

The "side billets" are the primary structural members of the Ribbot chassis. These parts are made of 6061 T6 aluminum and have over 40 different features. I was heavily involved in the design and manufacturing of these parts. I created the CAM for these parts in fusion 360, including roughing, finishing, surfacing, thread milling and rigid tapping. The tightest tolerances on this part were .001" on key bushings and structural mating surfaces.