Ilya's Personal reflection

There were a lot of new concepts that I learned about in ME 250. Working with Solidworks was my first exposure with CAD, and while it proved to be fairly challenging it is a valuable skill to have and was a necessary step in becoming a better Mechanical Engineer. The manufacturing part of the course was especially interesting to me, as I was excited to learn and work in the machine part. It is something that I enjoyed and learned a lot from and gave me a better sense of direction as to what type of engineering I want to do later in life.
Another aspect that was especially important was teamwork and time management. Our team had trouble coordinating when all four people were working together, and often times one or two people were not being very productive because most of the work was not made for four people to work on. It was also a lot easier to get off track and not be efficient with our time when working with everyone. To my surprise, working in teams of two was a lot more efficient and a lot more work could get done with two teams working on different aspects of the project.
My performance in this course is not what I had hoped it to be. This class was a lot more demanding than I had thought it would be, and my performance was limited because of the demands from my other classes. I felt that a lot of decisions were made in a rush, which never turned out well. Also, a lot of measurements were not made very well, and along with not giving a lot of room for error, this proved to cause a lot of errors. By the end of the project, we had much more success because we accounted for error in our measurements and our manufacturing.
I felt that the course could be improved in several ways. The first and foremost would be to have a lot more information about the assembly and manufacturing available before the start of those parts of the course. For example, our MCM was our cart, and the information about how to couple motors to axles, and how to constrict the wheels on the axles. When asking the GSI, their answer was that they had not come to a consensus at that time. Also, the thicker aluminum angle stock for pillow blocks was also made available too late for us. Having had information about these things earlier would have greatly benefitted our final machine. I would also like to add that a lot of the contents of our kit were not used, and probably cost a lot of money to be supplied. I think it would be better to have some general materials that everyone uses available to be in stock, but other materials such as magnets or gears or springs to be suggested, and be ordered online by the team through a set budget given to every team. This would save a lot of money and allow greater flexibility to the teams to be more creative. Also I think that The Arena was too constricting in its design. There were a limited amount of strategies we could use, and getting the balls in the bins through the cones was so much of a challenge that no one even attempted to score points that way. Similarly, the squash balls and the ball filled with sand were unrealistic to lift for almost every team, and were not even sought after by most. Making the game easier would allow for more creativity and more successful designs.

Final Blog Post of the Semester...

Hey there, fans of ME 250!

So it's all said and done, and ME 250 is over. Time flies, eh?

So Thursday was the Design Expo, and --unfortunately--we ran into some technical difficulties regarding our machine. We had seeded ourselves into the exact center of the competition bracket (and therefore earned ourself the slightly degrading "Most Average" award), and were pitted against Stiga. Unfortunately, just before testing, we discovered that our machine had been hurt in transit, and the planetary gearbox attached to our arm rotation axle wasn't working.

After competing in a very unexciting first round where no balls were actually moved, we were deemed the winning team because we were the closer of the two teams to actually scoring. Unfortunately, to compete in the next round, we would have had to take a planetary gearbox off of another team's machine to replace ours. Because of the way we had modified our gearbox coupling, however, we would have also had to exchange our coupling onto the new motor, which proved to be impossible because of the spring pin used to attached the coupling. The correct tools to remove this pin weren't available at the design competition, so this issue could not be resolved. For this reason, we were forced to forfeit our second round of play and were removed from the competition.

Despite this unfortunate turn of events, we still believe that we manufactured a simple design which could have been effective had it not been for our unfortunate breakage incident. We put in hours and hours of work into our design and manufacturing, and we are happy that we completed a workable prototype. Thanks to Sei Jin and all of fellow lab section 004ers--it was fun!

Have a safe and happy winter break, everyone!

Team 42

PS: Interested in an updated Bill of Materials? Check out this link for more info...

Figure 1: Our tiny cart prepares to battle Stiga's massive machine.

Figure 2: Dan readies our cart on the competition arena.

Figure 3: Adam and Dan are excited for the competition!

Dara's Personal Reflection

At the beginning of ME 250, I definitely felt overwhelmed.

As a non-ME major taking my second course in the department, I didn’t really know what to expect—after our introduction to the updated course on the first day of class, I was excited and nervous to start our machine, but after the first few homework assignments, I became completely discouraged by how much mechanical engineering knowledge I didn’t have. Through the entire first half of the course, I thought that I was destined to fail, but after studying hard and destroying the mid-term, I started to realize that I did have something to contribute to the class and to my group. Admittedly, I definitely could have pushed myself harder at the beginning of the term, but I think that I was so hung up on the challenge of the class that I had put up a mental block.

This realization was the chief thing I learned in ME 250: although I didn’t necessarily have the same skill set as everyone else in the class, my work ethic and general engineering knowledge could still benefit my design team. If this course continues to be open to students of all engineering disciplines, I suggest that this division of labor based on skill set become part of the project guidelines (i.e. that it’s fine or even encouraged to have specializations within your team).

In terms of more concrete engineering knowledge, I definitely learned more about bearings, gears, and springs than I ever thought I’d know in a lifetime. My favorite piece of information, however, was definitely the knowledge as to how a differential works—over Thanksgiving, I showed my dad and my stepmother the video we saw in class, and they were very impressed as to how much I had learned.

As far as how the course can be improved, I think that the administrative organization definitely appeared to be a bit weak from the viewpoint of the students—at some points, it was definitely frustrating to be crushed under a massive workload while not receiving any feedback on our output. Additionally, originally in the syllabus we were given more time in the final manufacturing stage of the course, but because deadlines on the administrative end kept being pushed back, we were eventually left with less than three weeks to completely manufacture our machines. This led to frustration among the students, the lab staff, and the course instructors which could have been prevented with some more careful planning.

As this course develops, I’m sure that improvements will be made—we were just lucky (or unlucky) enough to be the “guinea pigs” in this case. I would like to commend all of the GSIs who worked on this course, however; they clearly put in many more hours than were strictly required in the shop and advising us on our projects. It was clear at the design expo competition that they truly cared about all of their students (with perhaps the most glaring example of this being the “Sei Jin’s Army” team). They did a great job promoting camaraderie amongst the students—it was clear from the beginning that we were against the project and the arena rather than against each other.

All in all, ME 250 was definitely an experience, and I did learn many things throughout the course about design and manufacturing. Although I won’t be taking ME 350 any time soon, I can now understand how this material is helpful and worthwhile to my field of study.

Happy winter break, everyone!

Dara Fisher

Dan's Individual Reflection

During the course of ME 250, I learned several valuable lessons:

• During the design process, it is very important to keep the manufacturing processes in mind, in order that you don't design yourself into a corner, so to say. Our lives in the machine shop probably would have been a little easier had we taken the limitations of our manufacturing processes into account. For example, we designed our driven axles to be press-fit directly onto the double-gearbox drive shafts after getting approval from one of the GSIs. However, upon taking our drive shaft and axle to the machine shop and explaining to Bob what we intended to do, we were informed that there was no good way to do that with the tools that are available to us. Once we finally managed to press-fit the two parts together, an unexpected speed bump in our assembly popped up: trying to assemble the double gearbox again, this time with axles press fit on the drive shaft. Had we foreseen these issues, we could have come up with a design to save us all of the grief associated with our original, simple design.
• Follow through with all trains of thought on the design table. It is very easy to come up with a simple idea that seems as though it will work brilliantly at first glimpse; but if the thought isn't followed through on, problems may creep up unexpectedly farther down the road. It is much harder to fix things at the end of the design process than in the middle of it. For example, during the manufacturing process, some of our machining endeavors didn't turn out the way we expected, so we would try to modify our design slightly in order to accommodate the manufacturing flaws – but sometimes, these changes caused much bigger problems down the road because we didn't think our changes all the way through (akin to the Abbe principle of error; small flaws early in the process can end up resulting in much larger errors farther down the road).
• I also gained valuable teamwork experience, especially because our team had a diverse skill set, with different strengths and weaknesses – and working efficiently as a team required effective time management. Since we had to spend many hours together, either working on the homework assignments, or manufacturing in the machine shop, we had to especially manage our personal time well, to ensure homeworks and studying for other classes were completed on time.

Since there were so many changes to the course from previous semesters, it is understandable that it might be a little rough around the edges – unfortunately, a little rough is an understatement. From the beginning, the course workload was exorbitant, matching perhaps what might be expected of a 5 or 6 credit class. To add to the stresses of the beginning of the year, there were an excessive number of homework assignments due, but due dates changed without being formally announced.

However, the biggest shortcoming of this class was the complete failure to meet my needs as a student trying to learn practical machining operations. Out of 23 available lecture days, only one was devoted to the manufacturing processes that we were to use, and this occurred AFTER we started working in the shop. Since ME 250 is often a student's first exposure to design and manufacturing, it was impossible for us to adequately take into account the limitations of the manufacturing processes during the design stage of this class because that information was not made available to us in a timely fashion.

In addition to the shortcomings of the timeliness of the machining lecture, a single lecture in a passive learning environment is not sufficient preparation to enter the machine shop. To better prepare students, there should have been more student participation and more lectures devoted to practical machining. For example, students could have been involved in making sample calculations for turning speeds with different materials and feed parameters, so that they would be aware of what would be expected of them to know before they enter the machine shop. Also, the lectures could contain specific examples on how to practically generate particular geometries that students might need, instead of vaguely covering what such an operation would be called, and leaving it at that.

Another way that the manufacturing instruction might be improved is having labs focused on manufacturing processes, and actually performing some machining operations during our scheduled lab times. That way, students can have some hands-on experience in the machine shop early on in the course in a smaller class size. The lectures extensively covered the design aspect of this course; some of the labs devoted to design could be refocused on manufacturing without sacrificing the quality of design instruction.

I could have improved my performance in this class by being more prepared when entering the machine shop (having calculations already completed, and have plans of what to do in case either the tool we need is unavailable or if the machining does not result in a part that will fit our needs), and having more patience while working with the machinery. The quickest way of manufacturing a part is not necessarily the best way to do so.

Team 42 Videos!

Hey there, fans of ME 250!

So in the classic spirit of Team 42, we couldn't decide quite how to do our presentation video--pirates or monkeys? Future or past? To resolve this issue, we decided just to create two! The second video link in this post is our official submission and the first is just a treat for your viewing pleasure. Enjoy!

Happy almost-Design Expo!

Team 42

It's the Final Countdown

Hey there, fans of ME 250!

So we're sitting in an extremely crowded ME 250 shop, putting the finishing touches on our pride and joy. It's been a long road to this point, but we finally have a fully machined contraption ready to be tested on the arena. We were worried for a while, but it looks like we'll actually have a machine to present on Thursday! Hooray!

Although now we've gotten to this point, it was certainly a long road to get here. Machining this week was definitely difficult--we've broken a bandsaw, re-made parts, braided at least 20 feet of Kevlar thread, and run into all sorts of other issues. Each time, however, we've worked together as a team to solve our problems, and our finished machine is definitely a group effort.

All we have left to do is test with a control box, practice on the arena, and finish all of the documentation we have left.

NEWS FLASH: We've tested on the arena! Our machine drives (straight-ish) and moves the light ping pong balls! Right now we're filing down our PVC L-joint so it will fit more easily in the arena. That should be the last thing we need to do before we can just practice. We've also been filming fairly consistently as we've been working (much to the chagrin of our GSIs), so we should hopefully have a bang-up movie for Wednesday morning as well. Hopefully.

See you all at the Design Expo on Thursday! We'll have another full report before then.

Team 42

Figure 1: Laura is happy to be working, even if the lab is super busy!

Figure 2: Ilya and Adam work on preliminary wiring.

Figure 3: The cart waits in eager anticipation for the wiring to be completed.