Our team has been struggling with training rookies in CAD for the past several years. Training rookies to CAD competently is difficult, as CAD requires both extensive mechanism knowledge and familiarity with CAD software.
For this year, our team decided to teach CAD rookies to design basic mechanisms (e.g. a drivetrain using swerve modules) and have them participate in a pre-build season mini-robot competition hosted by a local team.
For reference, here is our rookie drivetrain CAD and mini robot’s cad: Drivetrain
Starting out with assemblies may work for some, but at that point it is virtual Lego. IMO you need to start with with basic parametric part creation and modification before you introduce multiple parts/assemblies. Most teams start the true novice with shaft spacers (3d printed, one sketch and maybe 3 features max), then work up to parts with half a dozen features (i.e. radio mount) before moving to assemblies. Never underestimate the power of 3d printing to motivate a rookie with CAD. Holding what you created is VERY satisfying. For the record my CAD class in MechE didn’t have assemblies until the last month of classes.
If you ONLY build with COTS and no custom fab then this may be a different story.
I suspect teams based in high schools have a CAD class. There are tons of YouTube but sometimes it’s hard to get started that way. I can also give a shameless plug for the Fusion 360 book I edited:
Try to look at it from a manufacturing and maintenance perspective. Have I communicated the critical dimensions / features? Are there sensible datums that you would measure from in the real world and give repeatable results? Have you parameterized all things that might change and made them relative (using expressions)?
We have tried using the tutorials that are provided with solidworks. They introduce basic principles of solidworks and have step by step instructions to introduce common topics
I know that I am a bit late to the party but what we have done is have people start out with learning how to make basic shapes in CAD then we slowly have then go off on there own and make the thing we want. Eventually we have them have more and more complex assemblies. Also having them do some homework can help but there is no set in stone method.
This year in the offseason our team used an online training program, Solidprofessor, which sponsors free access for FRC teams (see https://www.solidprofessor.com/first-robotics-competition-sponsorship/). They have a training course leading to the CSWA (Certified Solidworks Associate) exam, and Solidworks provides vouchers to waive the $100 test fee. Our students trained on their own time. During each team session we’d do a “Model Mayem” exercise and more experienced students would help the rookies when they got stuck. Several of our rookies and more experienced CADers took the exam. Solidprofessor does a good job, and it’s not only for Solidworks - several other CAD platforms are also covered.
This training didn’t really cover mechanism design, but having the CAD base has really helped. I think we are in the best shape CAD-wise we’ve ever been in.
Are you having difficulty teaching CAD or mechanical design?
Your post says CAD requires both mechanism knowledge and software familiarity. Those are two different things. I’d suggest considering whether a rookie’s difficulty is stemming from:
A) a fundamental unfamiliarity with mechatronics, materials, FRC design, etc. (mechanical design)
or
B) difficulty using the software to adequately represent their design ideas in a digital format (CAD)
As @rZhov stated, there are actually two different skill sets that CAD team members need to acquire, skills in creating the model using the CAD tool and knowing how to design the model. You will want your CAD team members to learn both skill sets.
Knowing how to create the model using the CAD tool is analogous to knowing the fundamentals of grammar and spelling and knowing how to use a word processor like MS WORD. There are many different training curricla available for the various CAD programs.
Knowing how to design the model is analogous to knowing how to write effective prose where one knows what to say that is appropriate for the occasion. It means knowing what mechanisms and materials will perform the functions needed and what will not.
It is not necessary to know how to use CAD tools to make a good design just like it is not necessary to know how to use WORD to write good prose. Before the 1980s, virtually all design work was done using pencil or ink on paper and writing was done by hand or with a typewriter. What is necessary is being able to do any calculations to determine what parts or materials are necessary to perform the functions required ie. calculating the proper gearbox ratio for X.
Some practical experience with the mechanisms and materials is mandatory so that one knows their strengths and weaknesses. It is also mandatory to have an understanding of basic physics. A course on “simple machines” would be very helpful to avoid designing mechanisms that are doomed to fail because they break the laws of physics.
One should also learn about the manufacturing processes available to the team and understand the limitations of those processes. Otherwise, one can easily design something that is not manufacturable.
Having the CAD team members participate in prototyping mechanisms will give them a lot of good insights relating to mechanisms, materials and manufacturing processes. I have noticed that the engineers I have worked with who participate in building the prototypes of their designs tend to produce better designs than those who do not.
It has been suggested that more experienced students can guide the trainees. Even better would be to find people who design complex mechanisms with moving parts using CAD tools to mentor them. They will have been exposed to many mechanisms and materials so they can advise on those choices and how to do the required calculations related to the physics principles relevant to the design.
Lastly, one needs to develop the willingness to iterate the design. I have noticed that it takes at least 3 iterations to get a good design in robotics as well as in my professional life in product design. Other good designers have done also stressed the importance of iteration. This means that time must be built into the schedule to allow for the iterations to occur. For many FRC teams, this will mean having the discipline and self-knowledge to choose a simpler design so that it can be refined through several iterations.
For students that are have gone through the most basic training, a fun exercise might be to give them a COTS or 3d printed part and let them make measurements and recreate it in CAD. If you’re just starting out, focusing less of your time designing and more of it getting familiar with the software and which features/techniques to use.
Ignore the text and fillets
I suggest a battery connector (a part that all teams have, I’m assuming) because it has enough features for there to be discrepancy, and likely improvements, in their recreation.
