Hi Teams, “How can I train CADers. What sort of CAD training do you do for your members, etc.”
I know these are common questions but people asked it every year, so I make this thread for FRC Teams to share your CAD training experiences. It would be helpful for both rookie teams or any team are struggling in making an effective training route for CAD team.
Criteri for a training program
Annual Schedule/Standard Curriculum
Human resources for CAD team
Recommended training resources
P/s: Feel free to request other questions, I will updated the list.
Here’s something I’ve struggled with while planning a CAD workshop for my team this spring.
I can teach people how to do CAD. I can go through the motions of creating a 2D sketch, extruding it, repeat. Then fillet/other things if necessary. Then place a few of these parts into an assembly, constrain it, and so on. That’s great, now I have taught a bunch of people to do CAD.
How do I teach design? Knowing how to do CAD is great but that doesn’t mean you can design a robot. I’ve got 3ish other people who can CAD but I found that I ended up designing most of the robot this year because they haven’t figured out how to turn a preliminary whiteboard sketch into something that’s durable, manufacturable, and serviceable. Not at all a knock against them; they just haven’t learned that. I think a lot of the blame for this falls on the course curriculum where they’ve learned Inventor… the way that they’re taught just doesn’t lend itself to many practical skills. Just how to do the basics and make a model that looks like something, not a model that’s actually manufacturable. That’s great when you’re doing it for a class but not great when you’re doing it for FRC and actually need to make the darn thing.
The team is great at ideating but it’s that final step of transforming that idea into something that could actually be made that is the challenge I think. How to break down a mechanism into simpler manufacturable parts, how to add fasteners in ways that enable the desired motion, how to pick reasonable materials to make it from, etc.
For example I’ve got this dynamite freshman who can CAD pretty much anything, but only once there are fairly detailed sketches of it. Plus I’ve got numerous others who would love to learn and I’m afraid of just teaching them how to use Autodesk Inventor without actually giving them the tools to succeed in designing a robot when I’m gone.
And for me that was just practice. Practice is what got me from designing a 2 stage gearbox, June 2018, to our entire robot, Jan-Apr 2019, in a few months. I knew that our CAD guy was graduating and that someone needed to pick it up ASAP if we wanted anything to happen in 2019. But it’s not realistic to expect everyone to put in the time.
I’m curious to see what approaches others have taken to overcome this.
What helped me as a student was doing exercises to build creativity. One thing was building a bridge over a 2 foot span with 3 inch sections of drinking straws, something where I needed to explore different solutions. Even if the solution doesn’t work or bends the rules you set, it can help develop creative thinking which is a necessary component when learning how to design.
Yes. Many people confuse the two skill sets. I have worked with many professional engineers who are very proficient at using CAD tools and are terrible designers, producing designs that are difficult and/or expensive to manufacture, difficult to service and perform poorly. Conversely, I have worked with a few great designers who did all their work with pencils and paper/vellum, before CAD became widespread.
An analogy to knowing how to operate a CAD program is knowing how to use a word processor such as WORD. Being proficient with a word processor does not mean one can write well. Conversely, one does not need a word processor to write well. I doubt that Ernest Hemmingway or William Shakespeare had access to word processors.
I use the word/writing metaphor myself!
Honestly with Onshape, we don’t even bother teaching CAD. The built in tutorials are good enough for the students to get them going on their own.
But as others have said, teaching design is the hard part. I think the big picture is teaching them about motors/JVN calculator, different types of fasteners, and all the other cots parts (gears, pulleys, versablocks, etc.) And how they feed into mechanisms.
I think it is critical for each team to come up with their own ‘design style’ that matches your manufacturing capabilities and inventory. We use the vex ecosystem (now with NEO motors) and build with tube and flat sheet metal and polycarbonate. This gives the students a subset of infinite possibilities so they can focus better and not be overwhelmed.
Past that, give design challenges/off season projects and then review and let them improve IN THE OFFSEASON.
I wouldn’t expect a student to start getting good at design until their 3rd or 4th year. I’m sure there are many students who are exceptions (especially those who frequent CD), but that’s my experience.
The biggest things that have helped me learn good robot design are:
Participating in the F4 Cadathons. You get to test your abilities in a time crunch as well as quickly see how other FRC designers approach the same problem which leads into my second point.
Download and analyze top robot’s CAD’s. I have a whole folder on my desktop of FRC Robot Assemblies that I will look through every now and then for inspiration or examples for similar mechanisms or good packaging ideas. I’d start by checking out 1678, 2451, 971 and 148.
Understand the essential physics and limitations of FRC robots and materials. Once I was able to actually understand how motor curves work I could use the JVN calculator and other tools much more effectively.
Steal from the best and Invent the rest. I have multiple times just created carbon clones of other team’s past designs and adapted them slightly for new challenges.
look through design discussions on Chief Delphi. I can’t tell you how many times I have remembered a simple little bit of advice that I read in a CD thread years ago that has helped out my designs.
The first and easiest is learning which buttons to poke. You don’t have to know what every button does to be good at FRC CAD. I use NX at work and I joke with people that I only know four commands, which is 90% of the pokes I make. You want to learn what buttons to poke, start by copying something that already exists. Over time you might learn short cuts.
The second part is build. A good CAD student knows how a robot is built. As has been said before, look at past robots. Most of this is knowing which COTS parts are needed, how they are assembled and hopefully how they are replaced/repaired. For most intakes you need all of the following:
Method to turn shaft (direct, gear, belt/pulley)
Motor with gear reduction.
Don’t forget about electronics.
Something that everything attaches to, which leads to…
The third part is fabrication. The CAD student eventually has to create a custom designed part out of a material you have. This part is different for every team but most FRC teams use similar materials (wood, aluminum, plastic). So given the material and tools the team has access to, what can you design that your team (or sponsor) can make that does what it’s supposed to do and doesn’t break.
The last part is what CAD is best used for and that’s to quickly confirm or reject prototypes. The 973 RAMP video about sketch design shows how quickly CAD can determine if an idea is within the rules and has the possibility to work.