Individual Reflection by Alex Buzzi

Individual Reflection
Alex Buzzi

    Mechanical Engineering 250 was by far the most enjoyable class I have taken this semester and probably in my two years here at the University of Michigan. From learning the array of bearings and bushing, to learning how to disassemble and assemble a bike, to mastering CAD Solidworks drawings, this class taught me several invaluable skills that I will be able to apply in the future. For me, the most intriguing part about ME250 was the hands on nature of the class, not only the lab, but in lectures as well. In large lecture rooms, such as the one we were in, it is easy to lose the attention of students, but by using simple tactics such as videos, demonstrations, props, and objects that were passed around, the lecturer was able to keep the attentiveness of the students. Also the ability to touch and actually see first hand how something operates assists in my learning of material a great deal and helps me comprehend how something works which, in turn, will be retained in my memory longer.
    Before this class, I had little to no experience with design, machining, or manufacturing of parts. I took a introductory engineering class my senior year of high school where I used a band saw and regular hand tools to create things, but this class opened my eyes to the extraordinary long process of design and machining. I would have never imagined all the work needed to create, for example, a properly dimensioned hollow cylindrical metal part. Although the challenges were present, the machine shop training and staff were fantastic and prepared us well for manufacturing of any parts. What was not mentioned in training, however, were the unexpected things that can go wrong during machining and the copious amount of issues a team may face. This was another fascinating thing about this course. You were always kept you on your feet. You were forced to analyze and envision new ideas and constantly had to face and overcome unfamiliar obstacles. One thing I wish our team had emphasized more is the brainstorming, design, and thought process behind our vehicle. Although surely everyone will eventually face an unexpected dilemma, several troubles could have been avoided if we had just thought them through a little more. One example of this was our MCM. Our MCM, the arm, was designed to fit two roller chains that folded outward when the axle was spun. Although some sag was considered, it turned out to be an utter failure. The motor did not spin nearly fast enough to prevent the sag. Luckily through some last minute decisions and use of copper wire we were able to make a temporary solution for the competition. A lesson learned was the importance on designing and calculations before construction. As William of Ockham (Occam’s razor) emphasized, the simplest answer or design is often correct. Before manufacturing, I learned, one must figure out the perfect, yet simplest design, and also plan for the unexpected. There should be a back up plan for every complex mechanism or design.
    Perhaps the most vital and meaningful concept that I learned was the value of teamwork and time management. Time management was incredibly important, especially in the latter part of the course, since we were only given a short amount of time to create our finished product. Although I generally regard myself as someone who manages his time well, time management with a group of people if far different. It was very rare for our whole team meet up with ample time to finish an assignment. With different availabilities and responsibilities, we found it very hard to meet as a whole group until nearly the due date of assignments. Luckily our group consisted of people who had specialties in specific areas. For example, one person in our group had a lot of experience with CAD so he took care of most of the drawings. Since we had people who were good at certain things, we were sometimes able to split up and work at our own convenience.
    All in all, I loved this class and took a lot from it. I now know how to use the lathe, milling machine, and drill press to create whatever part I desire(which I doubt most of my friends are capable of doing.) I learned the hardships, risks, and rewards of working with a team. I learned the importance of a proper design and the repercussions of an improper one. If I were to change one thing I may make the course a tad more balanced, in terms of work load, throughout the year. It seemed as though the first three-quarters of the term was relaxed and then, suddenly, all the major assignments, exam, and machining were allotted for the last quarter. Also another critique I have is the ambiguity of the requirements for assignments and unclear grading.  For example, for MS5, we went through the checklist and made sure we covered all the material needed in the powerpoint and thought we presented very well but received a poor grade. Also on the exam, when I had the correct answer on a problem but didn’t show all my work, most of the points were taken off. I believe, first of all, if I comprehend the material and find the right answer I should get full credit and second, it should have been stated in some form explicitly. Other than that ME250 was a unique, applicable and entertaining course.

Brad Chisholm Individual Reflection

            During the course of the semester, ME 250 has covered a number of subjects and developed numerous skills, both soft and hard, that will be useful in the manufacturing and engineering industry. Some soft skills that I learned through the milestones of this course are teamwork, time management and organization. Towards the beginning of the semester, teamwork was the main emphasis when our group was agreeing on both a team strategy and vehicle design. Some designs took several trials to get a final cut that we could all agree on. Time management was the main emphasis towards the end of the semester. This became most prominent during the final build of our vehicle when dozens of man-hours were required each week for the manufacturing portion of the course. Time management of who could be at the machine shop and at what time become a vital part of getting our vehicle done on time. The last soft skill that was built throughout the semester was organization. This was a constant requirement throughout the course as assignments were regular and workload was rarely routine, thus a need for organizational skills.

            Another valuable portion of ME 250 was the hard skills associated with the course material. While I had experience with computers and various software, I had little to no experience with CAD software. It was this exposure that will be useful in both finding and holding a career in the Engineering field. Also, the trainings and exercises with the some of the machines in the ME machine shop proved to be a learning experience for me, even though I have a background using heavy machinery and mechanical equipment. By the time shipping day came along, we found that there were many designs and components that we found were not as practical as we had thought they would be. These dilemmas were all very valuable learning experiences that taught us some of the things that need to be contemplated during the design process rather than the manufacturing stage. I think that all of these hard skills will be very useful in the field on a regular basis.

            One way I would improve the course is additional clarification. I often found that my group and I had trouble determining certain expectations, rules, and regulations. Also, it would have been highly beneficial to the quality of my group’s vehicle if shipping day was moved to the last week of classes rather than the Wednesday before. This would have left time to order aftermarket components from suppliers and also more time for calibrations and technique practice. We found that the time allotted was sufficient for vehicle design and prototype manufacturing, but we found little time for minor to moderate sized adjustments and redesigning for more practical components.

            Likely my largest downfall throughout the course was meeting deadlines. I found myself not prepared when a deadline for either a milestone or homework assignment came along. It was for this reason that I often found myself cutting corners and rushing at the last minute to complete tasks that I had not set aside an adequate amount of time to complete. Other than this small issue, I believe that in taking this class I am much better prepared for the engineering field after graduation.

Final Design

After a semester of hard work, the competition is over. Although we didn't fare well in the seeding round or the expo, our machine worked and we were able to score during practice. It was well assembled and the only system that didn't work consistently was the control box, which caused it to veer off course more than once during the seeding rounds and the expo itself. The main issue most likely dealt with faulty wiring as pushing forward on the controller did not result in the machine moving forward.

We used the double gearbox mounted on the bottom of the acrylic plate as the drive system. The axles went through pillow blocks made out of rectangular aluminum tube stock with bronze sleeve bearings press fit into them and we used 4in polyurethane wheels from McMaster-Carr. The rear of the machine was supported by a caster wheel, also listed in the bill of materials.

On top of the baseplate, the MCM was mounted using angled fasteners and a 1/8th inch aluminum sheet. We used the planetary gearbox for its rotational symmetry and the ease with which it can be mounted vertically. A 1/4th inch rod sticks up vertically as our MCM axle and has a length of plastic chain from McMaster attached using male electrical connectors, a 3in extension spring, and copper wire. The arm worked to perfection on the wave field and immediately knocked off two balls in range to capture with the copper wire beneath the machine covered in beads to avoid getting the balls stuck underneath before being able to control them enough to score.

Individual Reflection (Brian Zhang)

Individual Reflection

Brian Zhang

As someone who is heavily interested in design, whether it is industrial or product design, web or graphic design; I had a great interest in taking this class in spite of it being required. However, as I had taken 3 CAD-based classes in high school, the first part of the class was almost irrelevant to me, and provided little to no extensive knowledge on how to use SolidWorks beyond the basic commands. To this extent, many of the commands that I had to use later in the engineering drawings had to be looked up myself and discovered, which ended up using a lot of time allotted towards learning how to use commands rather than drawing actual parts. However, beyond that, the class actually did teach a lot of concepts not always necessarily related to design, but other things such as teamwork and time management.

Having taking Engineering 100: Design in the Real World, this was not my first experience with teams. Although the presentation we had during lecture was not terribly helpful, it did establish an atmosphere in the team that we would have to be proactive in doing the work for the project. It was not until we actually began to work on it that this became apparent. As the semester moved forward, our team would repeatedly meet last minute, occasionally meeting beforehand for a couple of the milestone assignments. As a team, we each had our own specific backgrounds and experiences—for example, having worked with CAD before, I did most of the engineering drawings, while other team members worked with machining or manufacturing. This made the division of tasks simpler, which proved to be beneficial if the entire team could not meet at one time. Furthermore, despite being good at different things, the general consensus was that each team member would be able to assist in any other aspect of the project as an extra hand in the machine shop, or another pair of eyes in doing calculations.

In terms of design and manufacturing, I learned a lot of the actual vocabulary and processes used. Even though I found an interest in design previously, it would be hard to say I knew the details of it; in essence, I was only interested in the aesthetics. However, after going through this class, I have learned the strenuous process that goes into designing something as simple as a chair or a table. Learning the specifics of bearings, bushings, and gears also increased my interest in the actual design process rather than only looking for the finished product.

One of the most important lessons learned during the duration of this course was that of time management. Aside from the usual, the difficulty not only came from being able to match schedules between team members, but also from estimating how much time we would need as a team in the machine shop. We could sign up for 2 hour time slots, so we tended to use that as a base for how much work we should do within that given time. However, more often than not, we would not be able to complete as much as we had hoped due to miscalculations, or underestimating the manufacturing processes that would be needed, and we would be required to stay longer, which would subsequently cut into time we would need to spend on other classes. Even after realizing this, it was still difficult to coordinate due to the limited number of machines and the limited number of team members available for each time slot.

Overall, the lessons learned from this course relied on the aforementioned mastery over time management. If our team's time was allocated better at the beginning of the semester, many of the troubles we encountered later on in the semester could have been avoided easily and would have left more time for improvement if needed. This could have been done through a more effective use of communication, as well as making sure everyone on the team was on the same page. However, despite all this, going through this course definitely opened my eyes more to the intricacies of design, and design as a team experience.

Individual Reflection from Marc Hensel

Individual Reflection

Marc Hensel

The Team Formerly Known as Prince

ME 250 has been a good educational experience with respect to the engineering and manufacturing processes, as well as with respect to teamwork, time management, and “reading the fine print.” I had no experience with CAD prior to this class, so it was obviously a lot of new material. During the work early on in the semester, I feel like I learned a lot about the design process and the manufacturing process independently of one another. We covered engineering drawings, which was very important in my mind, and basic manufacturing processes and concepts. Much later on in the semester, once we started to work on our projects on a regular basis, a number of nuances relating these topics came into light. There are many things that must be taken into account when designing a part that are not always clear until you actually try to make it. Holes can be exact size, oversize for clearance, or undersized significantly for tapping. Some things have to line up with each other, and some things will interfere with each other if they line up.

In addition to the relationship between designs and manufacturing processes, I feel that I also learned a lot of specifics about things like gears and bearings or specific manufacturing processes like computerized machining or molding. Although we did not get to see any of these in action, seeing the results in examples, as well as examples of large scale products which use the processes, was interesting at the very least.

Another topic that I felt this course helped me learn about was teamwork. The presentation we had on it was interesting, but actually being in a group was the most beneficial. Everybody is good and bad at different things, and likes or does not like doing different things. There are many different aspects of the whole process of making an idea into a physical, working object, and it is very important for the benefit of both the group and for the project that the team is diverse and there is at least one person good at everything necessary. For example, if every person is good at design but not particularly proficient at machining or documentation, then it will be difficult to meet all the requirements of the project.

One final thing that I learned a lot about from ME 250 was reading the fine print, per se, and figuring out what needs to be done without constant reminders from the professors/GSIs. Many assignments were laid out in one large statement or several small documents and we were expected to complete each part without much further direction, which I imagine is more like what actual product design jobs are like. This particular skill/realization has been very helpful this semester in making sure everything is done on time and adequately.

The most challenging thing about this class, aside from the fine print, was the fact that it is so bottom heavy and so much is due towards the end of the semester. Planning ahead to finish everything on time is difficult. I think that this is not something that the staff can really improve on, short of making more progress assignments and really stressing that we have to get stuff done early. This also ties into our performance and my personal performance. If I, and my team by extension, had started on things earlier and been more on top of everything in general it would have certainly been easier. My only other critique is that some of the grading is unclear or the requirements do not make sense. For example, when 3 manufactured parts were due, requiring 3 different processes and 2 materials seemed unnecessary and difficult to accomplish. We actually changed our design in order to meet these requirements at such an early date.

Otherwise, this was a very interesting class that affirmed my choice of Mechanical Engineering

Expo Tomorrow and Team Video Completed

The expo is tomorrow. We have a few minuscule adjustments to make in the morning, but other then that are finally done. A summary of our ME250 class and process in designing our machine this semester has been completed. Check it out:

Bill of Materials and Process Sheet

Here's the final bill of materials:
https://docs.google.com/spreadsheet/ccc?key=0AvdBh5mylGLpdHNINDZUTWpPSGt2Yml5UktaRVVQa2c#gid=0
And the process sheet:
https://docs.google.com/document/d/1i2JFw8IqVA-hilMTwhNifz11yDBClWX5P44RDJoaAGM/edit

Videos of Our Working Product

Tournament Bracket Out!

Below is our place on the bracket. We received a bye first round and therefore are in the second round. Lets Go!

Two Days Left Until Expo

There are now just two days left until the competition. Today we assembled our whole machine and everything fit into place nicely. We connected the motors to a control module today and both motors worked correctly. The movement of our vehicle is great and has little to no issues. One dilemma that was encountered was the slow rotation of the arm. This slow rotation led to the chains on the arm to sag lower than initially intended. Tonight our task is to brainstorm and resolve this predicament. Tomorrow we will test out ways to keep our chain from sagging.
Here are some images and videos of our work today:

Three Days Until Expo

There are officially three days left until the Expo. We are ready to perform and wreck the competition. A couple of minor details will be fixed across the next couple of days and we are beginning to make our video. Some video shots will be taken today and tomorrow in the shop and elsewhere.

MS9. Machine Almost Finished!

Our machine is almost done. Except for a couple of extra holes to be drilled and other minor details, our machine has all the parts ready to go. Now the hard task of assembly is underway. Photos are below of some holes being drilled in our chassis and our parts getting ready to be assembled.

MS8 completed

For MS8 our group was to have significant progress on our MCM completed and all engineering/drawings done for the rest of our machine. We are glad to announce that today our MCM is practically completed and all of our drawings are finished.
On my way back home from tireless hours in the machine shop, I was ambushed today by two wild turkeys on north campus. Here is an image of my close encounter.

MS7 completed

MS7 has been completed. After several hours in the machine shop, our group has finished three manufactured parts. Below are images of our work:

MCM update and MS7 underway

There has been a recent update to our Most Critical Module: the rotating arm. Our team met together this afternoon and discussed some concerns and potential issues. One issue that was brought up time and time again was the stability of our vehicle. With two rotating chains, flailing about, we pondered how stable our device would be. After many ideas were presented, a resolution to this problem was determined. We decided that one simple way to fix this problem was to attach the chains on opposite sides of the axle. Therefore as they spun they would counterbalance each other providing greater stability.
Now that this matter has been resolved, we will start MS7 immediately.

Motor Lab Completed. On to MS7.

Our team completed the Motor Lab today. Through a hands on assignment and set of instructions our team was able to assemble the planetary gearbox assembly and test its performance. Below are pictures of the lab in action:



Materials and Devices Needed for Motor Lab:

Assembly of Motor:

Brad Chisholm working diligently in assembly

Motor is Tested:

Brian Zhang demonstrating the correct usage of the tachometer

MS6 Completed

Our MS6 called for our team to make a decision on our Most Critical Module (MCM.) We came into agreement that our MCM will be our rotating arm. This was thought of as our MCM because it is our main source of grabbing balls and scoring during the upcoming competition. Our MCM will consist of a Tamiya 72001 Planetary Gearbox which will rotate an axle. On this axle, two acetal roller chains, cut to length, will be attached at certain heights. The placement of the chains will be based on the height of the balls on the wave field. One chain will be situated higher and be longer to reach the balls on the top of the wave field. The second chain will be slightly shorter and also lower to knock the balls on the lower level of the wave field.

Team Schedule

Team Schedule
This is the general schedule for what our team will be doing from now until the end of the semester. Keep in mind that this schedule is dynamic, and therefore is subject to change as we see fit in order to compromise our own personal schedules.

Post #1 - Strategy and Machine Concept

"Hand of God"

This strategy employs an arm that can knock 2 or 4 higher scoring balls off of the wave field and trap them under the vehicle. After scoring these, drive to the opponents scoring hole and attempt to block it. Also be able to capture a ball from near the starting area or the lip of the tower in case something goes wrong.

Risks: 1. Opponent can score first/more

            2. Balls could roll off the table

            3. Balls could get stuck on the wave field and be unreachable

Countermeasures:        1. Use gearbox with maximum horsepower for fastest vehicle and practice driving

                                    2. Build the machine so it traps the balls as soon as they fall

3. Build the arm so it knocks the balls forward and directs them straight down into the mechanism that catches the balls

Figure 1: Basic strategy for the "Hand of God"

Figure 2: Solid Models of the "Hand of God"