Improving team's CAD skills

[ofekfischer]

hi,
I am an alumni of FRC currently studying mechanical engineering in university. I am also a solidworks mentor in my team. Throughout the season we've had many CAD related delays. It seems that the preparation during the pre-season wasn't good enough (too short and not organized mostly). As for preparation for next season, I believe that it would be good to start as early as possible, so we will be ready next season. That's where things get tricky. I'm planning to work with the CAD team and teach them first the basics of mechanics (as the make the detailed planning of the robot) and some technical drawing, and than move on to solidworks. It is clear to me that it won't be possible to get them to a level where they completely master the software, as it will be limited in time since they have their high-school duties, and it's off-season. Therefore, I am thinking on witch tools/features are the most FRC relevant ones and witch should be left to self learning through some kind of exercising/project. We have a sponsor who manufactures the parts for us, mostly with sheet metal, thus I would focus on that, but also with cnc for some more complicated parts. What other tips do you have for CAD training specifically for FRC?

[BenjiSG]

Our team attempted pre-build season training sessions in Creo using the How to Model Almost Anything tutorial. That was all well and good and all, but new students didn't seem to get a grasp on practically using the software from it.

The project route is seemingly the much better route to go once you've gotten past all of the necessary tutorials. Following our CAD training sessions this year, we got some of our Sophomores and Freshman students to run a project to design and build a simple robotics arm (back when rumors were circulating of the 2016 game being an arm game). It worked very well in teaching some of our Sophomore build leaders the process behind designing and CADing robot pieces, and proved to be far more engaging than the tutorials ever were.

[RobotDoktor]

Simbotics made an excellent Youtube series about using Solidworks. Even if you aren't using Solidworks there are some good practices you can apply to other programs. The biggest thing they don't cover is going from a model to a finished product. If you are using computerized manufacturing (3d printing, plasma cutter, etc) you will want to learn how to export the correct files. If someone does machining for you you will want to be able to created well annotated 2d drawings from your 3d model. Using the appropriate "hole wizard" tool helps greatly in this regard as it makes it easier to label which drill and tap are used for a hole. If you have someone doing sheet metal bending for parts remember to tell them which side is which. We once had some platforms that got bent upside down, fortunately we could still use them though.

[MechEng83]

I've found the biggest hurdle isn't teaching a specific function of your chosen CAD package, but getting the kids to create (and modify) geometry so it's got the most parametric features possible. Basic tutorials will get them trained adequately on how to sketch, constrain, extrude, etc.

I find students naturally tend to use CAD like it's a combination of Legos and a series of cutting dies.

Examples of modeling practices I've seen which are unconducive to fast design:

Piece is 10 inches long. Want to modify to make it 13 inches. Extend end face by 3 inches, rather than modify the extrusion to increase its length.

Individually model and dimension each hole rather than using a pattern, or at the very least using an equal constraint for the hole diameters.

Needing to increase or decrease the size of a cut, and using the extrude option rather than modifying the original cut.

Spending a lot of time trying to calculate a Cartesian coordinate for a hole center (that ends up not lining up in a hole to hole axis mating), rather than using geometric constraints. Alternatively, not using construction geometry.


All in all, it's conceptual design that eludes them. Use of the CAD functions comes with practice. I try to teach them by walking through how I would make a certain part while taking breaks to explain quirks or watch-outs of the tools I used to make the part.

[b1nary]

as cad/design wasn't my primary team, i mainly did non-build work. but i found that experimentation with cad software works well, as well as designing in photoshop or some other program that has chances to work with dimensions, crafting, and organization. you can also download files for your cad software to work from and observe off the web, that's a good starting point too.

[skypatrol]

I strongly suggest getting the students experienced with fabricating the parts themselves. It gives them an understanding of the limits and capabilities of tools, which is necessary for basic level design. As with the exact methods they use to design, formal training and instruction won't help a considerable amount, those will improve with experience. Also, let them make mistakes, letting them learn from their mistakes on their own is the best thing you can teach them.

[B95]

I agree with skypatrol in that it is important to understand limitations in fabrication, as it's especially easy to design a part that is impossible to create.

When I took the CAD and design class at our school, there was one assignment in which we were given an object with a complex shape and a maximum number of modeling features (individual extrusions/revolutions/lofts, not sure of the Solidworks equivalent) we could use to make it. I think this helped me greatly in finding how to make an object the most efficient way and what tool to use in order to get my idea from my head and into the part.

Additionally, this year I was looking at a part from a previous year's robot because we were creating a similar system for this year's, and I found myself appreciating how the tools were used to create it. This may also help in learning the software.

[sawhneyjalaj]

For basic drawings, one thing that is important is getting students to not focus on making it perfect when drawing initially. Do a rough sketch, make sure you have all elements together, and then dimension it and let Solidworks put it together. It's much faster to throw on dimensions and constraints rather than painstakingly draw lines as perfect as you can get them. Features that are mostly FRC related... Hmm... Making drawings, focus more on assemblies rather than actually drafting parts (most of the time anything you may need to draw would already have a CAD model online), hole wizards, sheet metal, extruded cuts/boss and fillets/chamfers, also focus on constraints (such as a face is 1.2in from another face or can pivot 12degs in each direction)... Other than that, giving them pet projects to make to practice.

[Collin Stiers]

I have no experience directly with solid works, but I have used autodesk inventor a lot. In that what I have found works best is learning by doing. When i learned CAD through a course at my school it was pretty much "here's the toolkit, here's projects, do them" This was a full year course, so we had plenty of time to mess around, and it seems that you may not have that time. If you primarily use sheet metal, the Sketching tools/ 2D design tools seem like they would be the most useful, once you get the design draw out most of the work is done. Another thing I would recommend is having the people who make the CAD's be the same people who make the designs, it's much easier to get something from your head into CAD than it is to have to try and have the designers communicate to the CADers and potentially have something lost in that process.