Robotics Education & Competition Foundation
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V5 Mounting System

104

DevinH
Entry ID #: 5910
Created: Sun, Jan 13, 2019 12:23 AM


V5 Mounting System

CAD and Report by Devin Ho

3D Printing and .stl Conversions by Alan Onuma

Introduction

The V5 Mounting System is an extension of the existing parts used to mount V5 Electronics. There is no way to mount the V5 Brain, Battery, Vision Sensor, and Radio in ways other than what the flanges, battery clip, or existing screw inserts allow. This means that teams must use bulky and inconvenient metal structures to mount these parts in different orientations. These parts allow teams to mount their V5 Electronics in different ways.

Mounting Rails

The two mounting rails allow the V5 Electronics to be mounted across gaps, elevated, and on the undersides of each other. The long rail spans the length of the V5 Brain and the short rail spans the width. The rail is designed to be structurally stable, manufacturable via injection molding, and accommodating for attachment hardware. The top of the rail includes three sets of holes for screws, two at the ends for mounting the rail to structure and one in the middle for mounting V5 electronics. The holes are not just circles so screws can be placed multiple places. The top also contains a raised “lip” so the V5 Battery Clips can fit between them or screw heads and nuts can be rest within the enclosed area while the V5 Brain is mounted on top. This ensures the V5 brain can rest on the rail while leaving room for screws and nuts to mount things under the V5. The underside includes ribs and a uniform wall thickness for injection molding.

Mounting Bracket

The mounting bracket is intended to be used in conjunction with the mounting rails to provide a 90 degree mounting angle or with the vision sensor. Currently, the vision sensor can only be mounted via the screw inserts on its back. This part allows the vision sensor to be mounted perpendicularly to a surface, have room for the wire on the bottom, and be mounted at variable height. The bracket includes a long section to mount the vision sensor and a short section to mount to a structural component. This bracket can also fit between the mounting rail’s raised lips. The underside also includes ribs and a uniform wall thickness for injection molding.

Part Creation

To make these parts, I used Autodesk Inventor Professional 2019 64-Bit Edition, Build 136. I began with the long mounting rail. I began by creating a drawing the top lip of the rail and extruding it with a taper of 1.5 degrees. Then, I created the bottom portion with a drawing from the lip, then extruding it downward with a taper of 1.5 degrees. Then, I created a drawing at the bottom and cut extruded the screw holes. Then, I created another sketch and used the offset tool to make offsets 0.06 inches from the edge of the bottom portion and the holes. These were then used for an extrude cut with a 1.5 degree taper to create the fairly constant wall thickness of 0.06 inches. Then, I made another sketch on the bottom of the part and drew lines representing the ribs for structure. I then used the rib tool to create ribs with a 1.5 degree draft angle and 0.04 inch thickness. Lastly, I used the fillet tool to fillet all edges except the screw holes.

The second part I created was the short mounting rail. This required me to take the long rail and shorten the length dimensions. I worked my way backwards changing each sketch. I first started with last created sketch and moved to the first. I had to edit each sketch backwards because the each subsequent sketch is dependent on the previous one, so if I edited the sketches in the “forward” direction, the next sketches would be messed up due to their dependency on the previous one.

The last part I created was the mounting bracket. I began with a sketch and extrusion of the tall vertical part of the bracket including the screw holes. Then, I extruded the shorter, bottom section of the bracket from the existing vertical portion. Both of these had a taper of 0.5 degrees. Next, I added the hole on the bottom portion with a simple sketch and cut. Like the rails, I created the other cut extrude to create constant wall thickness, this time of 0.05 inches. Then, I created the ribs via a sketch and rib tool with 1 degree draft angle and 0.04 inch thickness. Lastly, I filleted all edges except the screw holes.

To make the .stl files, I sent the CAD files in the .step format to Alan Onuma, my teammate, so he can open the files up in an older version of Autodesk. He then edited my .step files to be 3D-Printer Friendly and exported them as .stl files.

Conclusion

This project taught me a lot about creating plastic parts. To create even the simplest plastic part requires a conscious effort to make sure it can be manufactured using the given machine. After analyzing the V5 parts, I realized that they were most likely injection molded. From my research, I learned about draft angles, ribs, and how a part must be designed so it can not only be molded, but released from the mold.

CAD software helps quicken designing a part because I can make changes quickly. It also allows me to stay conscious that the part should be manufacturable. In terms of competition robotics, I do and will use CAD to assist with designing robots. CAD has helped me assemble subsystems of the robot with low tolerances and plan before building. In terms of my career, I hope to be an Aerospace Engineer. CAD will help me not only with design, but simulation. There are features in software like Autodesk Inventor which computes simulations. These will be helpful in professional applications where real models are impractical.