Teaching CAD to new students

Hey everyone! my name is Gal and I am the new head of CAD and modeling in my team. our crew this year have new members and i was wondering how do other teams do CAD training and teaching and what cool ideas for activities to teach software understanding do you suggest doing?
we are using SOLIDWORKS 2019, until this point they learned how make a proper sketch and they started doing the SOLIDWORKS tutorials.
Thank you very much!

-Gal-

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Hello!

So this season I have been using a brand new training style/approach for our incoming CAD Students, and so far it has been a great success!

Part 1

To start, I had them follow the built in Solidworks tutorials.

Part 2

Next, they watched videos by Vertanux1. Specifically, they did the first 6 videos in this playlist which covers basic parts, assemblies, and drawings. They also learn how to use GrabCAD for file management, which I heavily recommend!

Part 3

Getting a little more advanced here. Had them watch a decent portion of the 973 Ramp videos. Also included a gearbox plate tutorial from 254, and the designing with pulleys videos from WCP.

Part 4

This is where we are currently at. The plan is to get them to take all of the skills they have learned in the previous steps and apply those to make a West Coast Drivetrain, it’ll be very similar to this guide from VexPro. I say similar, because we will be incorporating elements that my team would like to explore running in the 2020 season. Things like 4" wheels, NEO motors, #25 chain, ECT. This is great because they will be working on something extremely useful to the team. Additionally this is where I emphasized my team’s file organization and part naming scheme. It’s similar to what 254 uses. They learn to use our COTS library of parts, which is a cloned copy of Spectrum’s. Finally, they also get used to the construction methods we use, including 2x1 tubing, rivet + gusset construction, and snap ring detained drive shafts.

Part 5

The plan for part 5 is a 3D printing project. I’m still not entirely sure where we want to go with this, but my inclination is to maybe do something with pulleys and belts.

Part 6

Part 6 is basically the end goal. Here they will be going off on their own and designing whole subsystems to gain more confidence and experience, while also designing for FRC specifically.

Other

In addition to everything above, my team is currently in the middle of a redesign of our 2019 robot, so throughout training there has been opportunities for the kids to actively contribute to the redesign by creating parts, and part and assembly drawings for the things that are getting built and assembled. This feedback loop where they can see the things they design/create drawings for get built and come alive is awesome to see, and an important part of the process! This is part of the reason for part 5.

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It’s always a good idea to continue to give them projects that they can try out and just let them loose to see how each student tries to solve problems, but the main issue with people that join CAD is that they are not very mechanical. They can put 3d parts together all day long, but never really understand wether they work or not. That’s why you need to make sure that each CAD student either has experience or is currently also working in build so they can understand how their CAD is supposed to work in real life. Another way to help them understand is to have them make a part or assembly and then 3d print it and find their flaws with trying to assemble it or stress test it. It’s better for the students to see and understand how the CAD should be designed than for you to tell them how it will go and why some of their ideas would not work.

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Our team’s approach to teaching CAD is that in their first year, the members focus on the physical build and how they can use the already made CAD models to check measurements or change sketches to make a small change. The whole point is that they have basic machining and hands on experience so that they can make the distinction of an elegant 3D model vs. an usable part that go on a robot. We then start them by teaching them how to make the parts for a basic drivetrain frame, then put them together. We have a google drive folder for FRC specific CAD with a variety of videos on how to do ______ (you name it, we have it!). Then the most important part, practice, comes from a variety of CAD challenges, such as an elevator, intake, shooter etc. I would recommend searching around for FRC CADathon challenges as they have an imaginary game with a full game manual. That way, the students practice what they would have to do in build, design a mechanism for a game that’s new and no robots exist for that specific game. Another important part is to make sure you are able to help them as they need support otherwise it’s easy to lose motivation to learn CAD.

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As far as raw CAD education goes, I’ve found that people learn best by tinkering around on their own. However, they need to be walked through the basics. People need to be taught:

What is CAD? What should you use it for, what should you not use it for?
How does parametric CAD work? (in the basic sense, “you turn 2D shapes into 3D ones”)
How to make a new part
How to make a sketch
How to extrude a sketch into a shape
How to revolve a sketch
How to edit an existing feature
How to make an assembly
How mates work

I usually run through making and asembling a few parts:
A 2x1 bar
A corner bracket
An axle
How to assemble those into a simple chassis
This year I also ran through how to make a gearbox plate, but only because I had extra time.

After that, it’s pretty much on the students to mess around in SW and learn on their own. I do design reviews and police best practices when I get the opportunity.

Thank you!

Our team uses a bunch of the above mentioned methods, but also, inspired by @marcusbernstein, has kids make a ball. It helps them understand conceptually how CAD works, and how an extruded square can be the most effective way to make a sphere.

There’s a few other projects I can think of.

Adding a belly pan and package electrical components.

Mesh the belly pan and do an analysis to see if it’s robust. (something I don’t know how to do but would like to, the analysis part, not the mesh part.)

Know how to select a motor and gear reduction with/without chain to move/hold an arm of a certain length x that has a weight y at the end of it.

Cascade elevator with chain.
Cascade elevator with pulleys/cable.
Continuous elevator with pulleys/cable.

Roller intake, vertical and horizontal.

Build the parts they design so they know how easy/hard it is to create when they have dimensions ending in tenths, hundredths, thousandths…

Something with pneumatic actuator. Maybe several somethings.

Add tool paths to a design to check if the part is easy/hard to repair.

I’m in a similar situation. I was planning on some workshops to just teach the basics.

how can an extruded square be the most effective way to make a sphere?

I know in solidworks, all you need to do is revolve a circle.

Speaking from experience… if you want to teach a lesson, have a student do two 3-D printed parts where one has a non-obvious issue with fitting to the other. You may need to get tricky with this as far as what you’re looking for, but you want one part to go into the other’s volume. Print it. THEN explain about the “Find interference” function and how it could have prevented reworking the parts.

Oh, and one other thing that you MUST, MUST, MUST, MUST include:

Drawing Generation

With feedback from the mechanical team. Ideally get the mechanical team onboard with a box of red pens–their job is to show why this part from the CAD team can’t be built accurately. Since I started pressing my team’s CAD crew on “So, where’s that dimension I need for this hole?” they’ve gotten a lot better at thinking about how to set up a drawing to be usable by the build team. I was pleasantly surprised when one of them landed a drawing with every dimension set from one end, and all the dimensions present, well before the end of build. Made life really easy.

In Onshape I usually just make an extruded square than fillet the corners to the radius, revolving a circle also works, but I like to have the person I’m teaching think more outside the box when CADing.

Though this “Outside the box”, it’s generally bad practice for a few reasons:

This creates two features rather than one. Generally you want to keep the number of features low.

A square has more line segments than a circle/half circle. Not really incredibly significant, but over time and in larger parts/assemblies this can impact performance.

What if the size of the circle changes? You then need to change the filet size as well.

I’d argue that with design you certainly want to think outside of the box, but when it comes to CAD best practices and KISS principles override thinking outside the box.

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I only do this as a very introductory Day 1 thing. In the real world you are totally right.

As the guy who taught @Mikeyl1836 how to CAD, I will clarify the nature of the cube-sphere exercise.

My CAD instruction happens in three parts.
A) I explain and you watch me do the thing
B) We do a similar thing together
C) You work through a different challenge relying on similar skills and understanding- a “prove-it!”

When teaching about fillets, my prove-it is often turning a cube into a sphere with only the fillet tool. We don’t use many cubes or spheres on our robots, and that certainly isn’t how I’d do it in real life, but the thinking exercise about fillet geometries (especially given that this is a day 1 lesson) helps folks wrap their heads around fillet curvature and thinking in 3d space.

Just one of many “prove-its”

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Learning the tools is great. Once you know what all the tools are an how they consume sketches then you can use any Parametric CAD software. You should always teach how to use the basic tools first just to get them aware of how to CAD

In my opinion the most important in teaching CAD isn’t the tools, but the workspace. You can’t start understanding how to use the tools without understanding:

  • How to Orient your part within the Origin Planes
  • Where to start building up your design
  • What kind of reference geometry you need

A good exercise is to have the trainee make a hitch pin. Watch how they do it? There are several different ways to make the holes in a hitch pin, Challenge them to make the pin differently several times. Examples of making this pin:

  • Orient the first sketch, so an origin plane is tangent to the surface, use that plane to extrude the hole
  • Orient the first sketch, so that an origin plan bisects the sketch, use that plane as a mid plane for an extrude for the hole
  • Use reference Geometry to make a tangent plane to extrude the hole.
  • Make the initial sketch a partial circle with a flat. Use that flat to make a hole, extrude an arc to make the pin a circle, use the first hole to cut a hole in the new extrude.

After they learn the basic tools, how to use the workspace, then challenge them on how to make things with the least amount of steps. Go and make a part with a lot of features that use a lot of tools. Have the trainee make this part, and then compare part trees. Challenge the trainee to make the part with a equal or smaller part tree than yours. If they need help remind them about tools they are forgetting to use, and give them some hints on orienting the part.

I am the head of CAD and Design on my team and this offseason, we are trying to highlight training so we can hit the ground runnin in January. We have created our OWN standards on CAD expertise. The first thing we do is sort our CADders into groups

  • Experienced
  • Knowledgable
  • New
    We have five levels, and we start the new kids at level one, knowledgable at two, and experienced at four. My team uses something called SolidProffessor. It does require a subscription however. It is very useful and goes more in depth.

What I don’t see in new CADders is good design intent - which SolidProffessor teaches. It gives them videos and lessons to watch, and then parts with instructions on how to design them, assemble them, and test them. It’s a very helpful and easy to use system. I’d recommend looking into it.

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Don’t teach bad practice on day 1. That can result in students who build all of their CAD experience on rocky foundations. IMO, “outside the box” is usually the wrong way to CAD. Simple is better. Capturing design intent is one of the hardest things to teach, and making sure that all your early examples show design intent is important.

My only exception to that rule is using thin extrudes on a rectangle to make square tubing. It’s a little “outside the box” but it cuts the feature tree down and lets you control the wall thickness with 1 variable.

We’ve been developing our CAD instruction over the last couple years, and I think we’ve finally gotten to something that works really well. We believe that kids will learn CAD and mechanical design best by working on real projects, with experienced CADers around to guide them (instead of spending the whole fall in workshops). So we only do two 4-hour workshops, and they’re really more of a crash-course than an extensive curriculum, with the following goals:

  1. To get more students to the point of (very) basic proficiency. We’re actively trying to move away from “3 people do all the CAD and get completely burnt out”, and towards everyone being able to pitch in when needed, especially on small things like a battery holder or camera mount.
  2. To reinforce best practices. When there’s no formal instruction, people figure out hacky ways to do stuff that ends up making the robot CAD an impenetrable tangle that’s hard to edit or collaborate on. This way even if most of their learning happens on their own, they at least remember that they need to fully define their sketches, and that there’s a way to edit properly instead of by adding cuts and extrudes ad infinitum.
  3. To get new members’ feet wet, so that they see that CAD isn’t that intimidating, and get enough of a feel for it to decide if they want to learn more.

We chose to model our workshops around a smallish mechanism from the previous year’s robot - over the summer we did an elevator gearbox. We started with a brief discussion of “what is CAD and why do we bother”, and then a short overview of how we design gearboxes (JVNCalc!). Then we walk the students through how to make some of the parts. The student CAD captain explains and shows them how to make the parts by CADing them in real time on a projector, while I (the mentor) walks around and helps kids when they get stuck or have problems. We also had handouts for them, showing the general steps and with relevant icons highlighted. They CAD at least one plate, one spacer, one shaft, etc, and we make sure to work in insight to best practices. We also have them find and import a part from McMaster, because we do a lot of that and it’s mildly tricky in OnShape. When they’ve made the parts, we talk about drawings. They make drawings for one or two of the parts, and we talk at length about best practices for drawings.

At the second workshop we focus on assemblies. We give them the gearbox parts they didn’t make last time, and go over degrees of freedom, all the different kinds of mates. The captain walks through how to assemble the gearbox on the projector, along with a few other things like editing in context, while I walk around helping students. At the very end, we go over and look at the actual gearbox on the robot and admire how much the assemblies they just made look like the real thing.

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