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5. SlotLock Variety Pack

SlotLock Variety Pack CAD, Report, and 3D Printing: Alan Onuma Robot Integration: Jonathon Bower Video: Kelly Zhou Introduction: Currently there are no VEX products that give teams a simple way to lock any fold-out mechanisms. Instead, teams must use bulky multi-part systems, using many rubber bands to retain their parts in place. The SlotLock Variety Pack provides a clean and elegant way for teams to lock their fold-out mechanisms at either a 180, 135, or 90 degree angle. SlotLocks: The SlotLocks are meant to be mounted on the stationary pivot point of a robot’s fold-out mechanism. Each SlotLock includes two mounting holes (one that has a hole for a hex nut and one for a normal screw hole), an additional hole to install a standoff to hook a rubber band on, a hole to add a screw to help guide the rubber band, and an arc-shaped track for a screw to follow. The locking mechanism works by using a movable screw, which is attached to your fold-out mechanism. It follows the arc-shaped track, being pulled by a rubber band and eventually gets pulled into the slot at the end of the track, locking it in place. This pack includes a 180, 135, and 90-degree variant for either the left or right side of a robot. SlotLocks were designed to be structurally stable and manufacturable through injection molding. Each SlotLock includes ribs, fillets, a uniform wall thickness, and a shell on the bottom of the part. Screw Guide: The Screw Guide is mounted on the pivot point of a moving fold-out mechanism. It has three holes for mounting and a slot for the moving screw. This part is used to provide a sturdy pivot point for the moving part. It also guides and secures the moving screw that will eventually lock into the slot on the SlotLock. The Screw Guide was designed to be structurally stable and manufacturable through injection molding. The part includes ribs, fillets, a uniform wall thickness, and a shell on the bottom of the part. Part Creation: To CAD these parts, I used Autodesk Inventor Professional 2018 64-bit edition. I started with the 180 degree SlotLock for the left side. I began by drawing out the holes for all the screws, the hexagon for the nut, and the arc-shaped track for the moving screw. I then used the offset tool to offset each of these features by 0.06 inches. To finish the sketch, I used the line tool and tangent constraint to create the perimeter of the part . Using the extrusion tool, I extruded the bottom half of the part and then using the same sketch extruded the top half of the part. I created a constant wall thickness of 0.06 inches on the bottom of the part, using the shell tool. After, I used the sketch and rib tool to connect all the holes together. I also used the draft tool to create a 1.5 degree draft throughout the part. Lastly, I used the fillet tool to create 0.03 inch fillets on the inside edges of my part and 0.06 inch fillets on the outside edges of my part. To create the right side variant I simply reversed my two initial extrusions and then repeated the same process. For the 135 and 90 degree variants I repeated the process above. To create the last part, the Screw Guide, I first started by sketching the screw holes and the slot for the moving screw. I then used the offset tool to offset each of these features by 0.06 inches. Next I used the rectangle tool to create the perimeter of the part. After finishing the sketch, I extruded the top and bottom half of the part similarly to the SlotLocks. I then created a shell on the bottom of the part, keeping a 0.06 inch wall thickness. After the shell, I made ribs connecting all the holes together using the sketch and rib tools. Then I used the draft tool to create a 1.5 degree draft throughout the part. To end the part I then create 0.03 inch fillets on the inside edges of my part and 0.06 inch fillets on the outside edges of my part. Conclusion: This project reinforced the importance of CAD software to me and opened my eyes into the complexities of injection molding and designing plastic parts. Through my research on injection molding, I learned about the necessity of draft angles for helping to release parts from the mold, ribs to help with structure, fillets for minimizing stress, and a constant wall thickness to help with fluid flow. CAD software has allowed me to create parts that can easily be modified for a variety of applications. I have used Inventor and Autodesk HSM throughout my high school VEX career, for designing, prototyping and creating custom polycarbonate parts for our robots. In fact, during this season alone, I created 18 versions of The SlotLock mechanism for our robot. It worked successfully during competitions and inspired me to submit this entry for the CAD challenge (see pictures and video for more detail). In addition, I have used Inventor to create numerous personal projects on the 3D printer and CNC routers. With each passing year in VEX, I have used CAD software more and more, and find more ways for it to benefit the projects I am involved. Besides fabricating parts, my team also uses CAD to design our subsystems before we begin building our robot. CAD helps us identify flaws, fine-tune our calculations and constraints, and helps us to produce a higher-quality robot before we even start to build. I currently aspire to become a mechanical engineer, with a focus in advanced manufacturing. CAD will undoubtedly play a big part in this profession, helping me to more efficiently and effectively design products. I am excited to find more ways to apply CAD and CAM technologies to the products I design in the future, both for professional and personal use.