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Discover the essential role of Computer-Aided Design (CAD) in robotics at Crescent School Team 610 with Rob Stehlik. This session covers selecting the best CAD program, including Solidworks and Autodesk Inventor, alongside practical design tips for creating efficient 2D sketches and transforming them into complex 3D parts and assemblies. Learn to streamline your designs with intelligent assembly tracking, weight management, and reliable resources for additional support. Unlock the potential of CAD as a powerful tool in your design process, beyond just creating pretty pictures.
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Using software for better designs ComputerAidedDesign Rob Stehlik, Crescent School (Team 610) rstehlik@crescentschool.org
Agenda • Which CAD program is best? • More than pretty pictures • The value of 2D • 3D parts and assemblies • Design tips • Demo: Gearbox design • Resources
Which CAD program is best? • The short answer: Solidworks! • Solidworks is fairly easy to use, and quite powerful. It’s also very common in industry. • But really it doesn’t matter, just use what you have • Learn what your mentors use • Both Autodesk Inventor and Solidworks are available free for students involved in FRC
More than pretty pictures • CAD is a tool for creating designs, not rendering super realistic images
The value of 2D • You can accomplish a lot with simple 2D sketches-robot layout -mechanism geometry -size constraints • Don’t rush to 3D • Examples: kicker designbump traverse
3D parts • Basic process: make a 2D sketch, then turn it into a 3D part • Combining simple features, you can make very complex parts • Demo: make a wheel
3D assemblies • Once you have a set of parts, you can put them together in an assembly • Assemblies help to make sure everything fits together, keep track of weight, create a bill of materials for ordering components • The more detailed your assembly, the smootheryour build
3D assemblies • Keep track of your weight • Assign materials to the parts • Example: wheel assembly • Coyobot VII, team 610 in 2006 Build weight: 142 lbs Regulation weight: 10,000 holes later
3D assemblies • Subassemblies help keep things organized, and make changes easier
Design Tips • Write out all of your requirements • Start with a standard material size(check mcmastercarr) • Work within your manufacturing capabilities • Talk to your machinists! • Download 3D models, but if possible measure the real thing
Gearbox Design Requirements -single speed gearbox-driven by one CIM motor-50:1 gear ratio-use AndyMark gears
Gearbox Design Some terminology and background info: • Gears are specified by the pitch, which is the number of teeth per inch • The pitch circle is an imaginary circle within the profiles of the teeth of a gear, such that it rotates against a similar circle on a meshing gear • So how do we determine the correct centre distance?
Gearbox Design • Pitch diameter can be calculated by D = N/p • Some common AndyMark gear sizes are shown here • Let’s choose our gears and design the gearbox!
FIRST CAD library http://www.firstcadlibrary.com/ MadTown robotics CAD library http://team1323.com/cad/index.html MadTown CAD tutorials http://www.team1323.com/pages/cad_tutorials.php FRC Designs http://www.frc-designs.com/index.html Resources
