Construction

The weapon shaft was made using a lathe (see figure 2) to achieve the high tolerances necessary to accommodate the weapon's needle bearings

The methods used to construct the device include 3D printing, CNC milling, standard milling, turning, and composite making. For the wheel modules and electronics module that make up the internal structure of the robot a 3D printer was used to print the parts out of TPU. TPU was selected due to its impact and abrasion resistance and its strength over other materials. The weapon blade was made using a combination of plasma cutting for the inserts and CNC milling for the weapon blade. The CNC operations were necessary due to the contours within the blade which were designed to relieve weight and reduce stress concentrations within the blade. The weapon shaft was turned on the lathe and was then hardened so that the needle bearings would not deform the surface of the shaft on impact. Finally, the top and bottom plates were made using carbon fiber which was originally pressed to 4mm thickness and then was going to be CNC milled to make the shape and create the weight relief holes which would be difficult to make with a standard mill. The decision was ultimately made to outsource the manufacturing of the carbon fiber top and bottom plates due to time constraints and concerns about quality. After assembly, the robot came out to 2.75 lbs. which allowed for the extra weight to be allocated to an outsourced AR500 steel blade which would be more durable than the aluminum blade.

Figure 3: Making The Weapon Shaft

Figure 1: Making First Wheel Module Print

The wheel modules were made using 3D printed TPU, the first try at printing this part resulted in some warping which affected the part's useability (see the rounded top edges in figure 1 above).

After making some changes to the 3D printer's settings and making some design changes to make more room for electronics in the electronics module, 2 successful wheel modules were made

Figure 2: First successful wheel modules

Figure 4: Laying up carbon fiber

Originally the carbon fiber was going to be made and machined in-house before the decision was made to outsource the carbon fiber parts through CNCmadness. To do this in-house, pre-preg carbon fiber was used and it was layered up with each layer being 90-degrees rotated from the previous. Figure 4 above shows how one layer was laid up. In the end, 75 layers were used to make each of the 4.5mm thick plates.

Figure 5: Pressing the carbon fiber

After layering the carbon fiber, it was then pressed together in a heated hydraulic press for at least 12 hours at 210 degrees F. This process allowed for all air bubbles and gaps to be pressed out between the layers of carbon fiber while the heat cured the pre-preg resin.

Figure 6: Finished carbon fiber plate

After the resin was pressed and cured a nice plate of carbon fiber was made and ready to be cut to shape.

Figure 7: Cutting aluminum stock

To start the process of making the weapon blade, a piece of 7075-T6 aluminum was cut and milled square before being cut to shape using the CNC mill.

Figure 8: Milling aluminum stock

Once the aluminum stock was prepared it was then cut to shape using the CNC mill. In Figure 8 above the holes to mount the weapon pulley are being drilled.

Figure 1: Dueling Robot Drawing Tree