For me, ME 250 was much more difficult then I originally intended. Coming into the class I already had some basic design and manufacturing experience, being that I took Energy Technology, Introduction to Automation and Robotics, and was involved in the Physics/Engineering Club in high school. Still, this class was definitely challenging for me.
At the beginning of the semester, the homework was much more time consuming than I originally expected. Three assignments due per week seemed a little excessive, and I wish they were spaced out a little more. The Solidworks assignments were difficult but that’s to be expected when you’re learning a new program. For the Design Reviews I wish there was more time in class to collaborate with classmates, as the peer reviews seemed more to really be more “let’s get this done quickly” than “let’s bounce ideas off each other.” However, the homework assignments seemed to be more much more geared towards physics than towards design and manufacturing. I feel like I would have rather had assignments that gives you a problem and materials and asks you to design something than some kinematics problems.
As for the actual project, I liked the idea of the arena. It was a project that none of us had ever had any experience with, and therefore allowed for some creative ideas. I would say from a manufacturing standpoint, we did a pretty good job with the design of our machine. The major flaw we had was constraining the worm gear. In our original design we did not account for this to be a problem, but in hindsight we definitely should have considered it, being that we were entrusting an aluminum couple with a 1/8” diameter to hold up the radial force being brought by a 36” long steel arm. We realized this flaw with only a couple days left before the competition, as when we finally put our project all together the worm deflected back instead of driving the motor. Because of the limited time left, we pretty much just threw together several constraints to hold it steady, but these ended up binding the worm because the constraints were actually misaligned. We didn’t figure this out until between rounds of the competition (our first run was a 0-0 tie), and we were extremely disappointed in the fact our machine wasn’t working properly when it was being graded, especially since all we had to do was take a misaligned constraint out. One possible way we could have avoided this in the design was to put a spur gear on a fixed axle behind the worm gear. The worm gear could then not deflect back because it’s being constrained by that axle. There would also be no energy lost (aside from the negligible moment of inertia of the gear), so there would be minimal lost power in the motor. A problem with this, however, is that we would have had to purchase a gear that was the same pitch as the worm and gear, and this probably would have put us dangerously close to the $100 limit, as we had already needed to purchase a lot. This can definitely be viewed as a positive, though, in that now I can guarantee I will never leave a motor couple under or over constrained ever again.
Overall I feel that the project was a good design project. However, the work at the beginning of the semester definitely seemed much too packed together. Time management was definitely difficult at the beginning, but I began enjoying the course much more once the project got underway. I definitely think this was a helpful course, and I definitely feel more experienced in Design and Manufacturing.
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