Sunday, December 11, 2011
ME250 is my favorite ME course so far. Working on the project was probably similar to working as an actual engineer in design. The class definitely got me more prepared as an engineer. At first, I was dreading this class since the first day. The project intimidated me because of how difficult it sounded and how much time I would need to spend on it. However, making the machine with my teammates was a fun and very valuable experience. I learned many new things in this class.
I was introduced to all sorts of components. Components that I thought were the most important were gears, fasteners, and bearings. Choosing a gear ratio was crucial to the project. We wanted our machine to move at a certain speed, so we had to choose the gear ratio that would’ve supported that speed. Gear ratios also give torque, which is sometimes important to design. Ultimately, we didn’t have to consider torque for our design. The concept of using different fasteners, whether we would use screws or bolts, was important in building our machine. In order for our machine to be stable and robust, all the connected parts were required to be attached with the correct fasteners. I thought bearings were most interesting among all the other components. Bearings made it possible for our machine to move efficiently as intended.
Manufacturing was my favorite part of the course because it was hands-on. The machines at the ME shop, such as the mill and lathe, are frequently used by engineers. I’m glad that I had the opportunity to learn how to use them. I got to learn many tools that I was unfamiliar with, especially the caliper. I also learned how to solder electrical components together. Having experience with these tools and machines will definitely come in handy in the future.
I already have prior experience in working in a team. I thought that Engr100 is the best course in terms of teamwork. But I was able to improve time management while in my ME250 team. This semester, I had a busy schedule including work and my other classes. The manufacturing process of our machine was the most time consuming. My other classes took place in the afternoon. Waking up earlier and spending the entire morning on making our machine was adequate.
There are a few things that I thought this course should improve on. The introduction to the ME shop wasn’t effective. We had to take training sessions two months before we even started building our machine. I think training sessions should take place much later so that remembering everything about the shop is easier. I feel that the exam was long and I didn’t have enough time to finish it. I think that the exam should be a little shorter in length, or maybe add several minutes. Even though my team and I finished the project on time, there should be more time for teams to build and test their machine. It’s probably best to assign the MS assignments earlier, especially the Most Critical Module.
The only thing I could’ve improved my performance in this course is my involvement in the design of our machine. An example of this is not coming up with the dimensions or materials of each part. Having more involvement would’ve resulted in me being a better designer as an individual.
I thought that everyone in my team was hardworking and was determined to do well in the class. I’m glad I was able to work with them all semester. I wish them the best in the future. We managed to finish 2nd in the design expo, and I have to say that I'm very proud of that achievement.
Derek Napierala –individual reflection
Overall I thought ME 250 was a great course. Going into the class I had slim to none experience working with metal, however in high school I had constructed many projects out of wood. At first working with metal scared me, I thought it would be much more difficult than wood and take much longer. However in this course I learned how to cut and shape metal (primarily aluminum) and get it to perform in a way I expected it to. I learned that metal is a much more reliable material than wood and while there some challenges to making it, with careful planning it can do much more than wood ever could.
Upon entering this course my approach to designing was to try something and see if it worked, if it didn’t adjust the design and make it better. However this course forced me to learn the value of taking the time to analyze a design in order to produce a better finished product. It is not always the best idea to jump with both feet in, and as I learned in the machine shop, without a proper drawing producing parts is almost impossible. Many errors in this project could have been accounted for with better initial preparation. However there is value to building a part in the shop, as limitations in a design are imposed with certain manufacturing techniques. For example, when designing the axle for our machine initially there was one single tapped hole through half of the axle for the set screw. But in order to tap the hole, clearance had to made through the entire axle, therefore I had to increase the hole depth to go through the entire axle. This just shows that both designing and manufacturing is important, because while you can design for most everything, there will always be one little glitch (if not many) that has to fixed after construction. Yet a good design will eliminate most of these glitches and produce a better functioning machine.
Another very important aspect of this course was teamwork. I was fortunate enough to have an amazing team; everyone on it was hardworking and exceeded my initial expectations. As a team we were able to decide upon an initial design, deciding what was too outlandish and what would work as expected. This method worked very well as we ended up going with a fairly simple machine, going after the balls on the front table and on top of the tower. What surprised me in the competition is that no other team was able to successfully score a ball from any other area of the arena besides the front table. This just shows that our team was able to come to a realistic final design and one that performed exactly to our expectations. Also working as a team taught me the importance of organization as we always had to work on the project together, and plan in advance when we wanted to work in the machine shop. I feel this is a very important life skill, because being organized saves lots of time in the long run.
While I learned a lot from this course there were areas to be improved upon. I felt that there was a lot of down time at the beginning of the semester during the planning session and the end was very rushed. Designing is important but it did not need to take as long as it did, and some of the deadlines could have been pushed forward in order to give more machining time at the end of the semester. But I did think the course was taught very well and the competition at the end was the highlight of my semester.
In conclusion I thought that this was a very valuable course and learned many new skills. This class taught me how to problem solve real world problems as well theoretical, but I know I will retain the practical knowledge I learned from this class for a long time. In terms of individual performance, I do not think I could have done much better as we ranked first in seeding and second overall in the competition. This course was a great benefit to me; I gained more confidence in my choice of mechanical engineering as a major and eagerly await design courses in the future.
Austin Murtland - Individual Reflection
Jake Atkinson - Individual Reflection
ME 250 was one of the most challenging and time consuming classes I have taken here at the University of Michigan so far. That being said, it was also one where I learned a ton, and one that I actually had fun in doing so. Coming in to this class, I couldn’t even begin to imagine how I was going to build a remote control vehicle and actually understand what I was doing. However, I learned so much about design and manufacturing, and was even able to construct a second-place machine in the process.
Before starting this class, I had no idea how to use a lathe or mill, I couldn’t tell you what a gear ratio was, and I had no clue how a control box, motor, battery, and gear box can function to turn an axle. But now, I know all of those things and I even have a fairly in depth understanding of each of them. It is amazing how much you can learn when you are working on a hands-on type of project.
I now understand how basic machines function and how components and processes work together to achieve the desired output. Furthermore, I have learned how to do simple analyses and calculations that provide insights into how a machine or certain components might perform given a specific situation. I also learned how to use a ton of different machines and tools in the shop, and I now even know most of the terminology for different tools and parts. Finally and most importantly, this class taught me the entire step-by-step process of designing and manufacturing a machine, from start to finish.
Aside from pure new knowledge, I was also able to hone my teamwork and time management skills. Throughout the semester, everything we did was done in a team of four students, and there was a lot to do. Therefore, we all had to make sure that we were working well together, which resulted in efficient use of our time. I think this is one reason why my team did so well in the competition and ultimately created a great machine.
However, there was definitely still room for improvement. One thing that we soon realized was a mistake, was coming to the machine shop without a detailed plan for how to manufacture a part or a clear drawing that was fully dimensions. We learned the hard way that a lot of time can be wasted in the shop if you have to continuously look up the machine running speed or the drill size for a specific hole, etc. Moreover, this creates chaos and disorganization in the shop. So, if I had to do it over again, I would make sure that our whole machine was fully planned out and designed with detailed drawings and manufacturing processes before starting to actually build it.
Overall, I think the course was a great one and I really only see one area for major improvement. Specifically, I think a lot of valuable time was wasted in the beginning of the semester. While obviously it is important that students first learn the necessary material in lectures before trying to implement it, I think things could have been done a bit more efficiently. I would suggest condensing a few of the original lectures, especially the one about creativity and teamwork, because as students at U of M, a lot of this material is either review or simply common knowledge. This way, the whole process could be moved forward by a few days and people wouldn’t be cramming quite as badly at the end.
Thursday, December 8, 2011
Bill of Materials
Wednesday, December 7, 2011
The building process definitely tested our capacity as engineers and problems solvers. We had issues with all three components of our mechanism: the driving mechanism, the front tray, and the arm. These problems ranged from press-fitting the axles into the bearings to finding a way to start with our arm extension bent and to have it expand, and even included bending the metal and the assembly of our front tray.
In terms of a description of our machine, we have:
-The driving mechanism: Our machine's driving mechanism works with a dual gearbox motor that control the front two wheels, which have an almost 4" diameter and a foam surface. In the back, a ball caster functions as a third wheel.
-The front tray: Using the water jet to cut out our front tray pieces, we bent these to make sure there wasn't too much friction between the tray and the balls. We then assembled these pieces by using 1/16" sheet metal bent into 90˚ brackets and using sheet metal screws. It is used to collect the balls and transport them to our scoring hole.
-The arm: The arm is just tall enough so that it doesn't exceed the 18" height limit, and it has an L-shaped piece attached to a spring hinge that expands after our machine starts moving. It is used to knock balls of the perches of the tower.
Finally, as you can see in our pictures, we painted the machine to make it look "nasty." The orange and black design is sure to scare away any formidable opponent.