Nathan's Class Reflection

This ME 250 course has been an extremely demanding class, both in the amount of time and effort I was required to put into it. I have put more effort into this class than I have any other class so far at the University of Michigan. That being said, I also feel like this class has been the most rewarding to me, and this class in particular is what really made know for sure that mechanical engineering is what I want to study and do for the rest of my life.

I have learned a tremendous amount about the design and manufacturing from this class. First of all, I really enjoyed learning how to use CAD. I had only taken one basic CAD class in high school, so I had some background with CAD, albeit very little. After finishing this course, I know have a thorough understanding of CAD and can use CAD to produce a wide range of parts and drawings. Also, I came into this class with absolutely no machining experience. It was intimidating at first, but after learning from Bob and John in the shop, the manufacturing labs in class, and my teammates, I was able to learn a whole lot about the various machining processes, and I felt confident in my ability to manufacture parts towards the end of the semester.

Also, this course improved my time management skills greatly. In order to complete all of the labs, homework assignments, and project work demanded of our team, we had to plan ahead in order to ensure we had enough time to complete all of our assigned work. Creating our group schedule really helped our team be able to accomplish all of these tasks, and is something I will definitely use in the future for other group projects and individual assignments or work I need to accomplish. Also, with regards to assignments for my other classes, I had to plan ahead to accomplish these because of the enormous amount of time required by this ME 250 course.

From this course, I have also learned how to work with teammates better and how to be a better teammate in order to make a better team. When working with a team, it is important to understand that I am not the only person on the team. Sometimes, it is better for one member of the team to step back and listen to your teammates, because no one person is always right. By listening to every member’s opinions, only then can you create a good team experience and produce the desired results of the group’s efforts.

Although this was a great course, I believe it can be improved in a number of ways. First of all, the majority of the time I put into this class was in the machine shop. I feel as if the lectures about the machining process did not do enough to prepare me for this. The two labs we had were very helpful; however, I feel as if they were not enough. Having more machining labs such as these would help greatly to teach students how to use the mill and the lathe. Also, I think linking the lectures to the projects would also be a lot more helpful. I feel as if this class is two separate halves; a lecture and a lab. Connecting the two better would make for a better course.

In order to improve my performance in this class, I feel as if it would have helped to have prior machine experience. Because I had no prior machining experience coming into the class, I feel as if I was sort of thrown into the fire with respect to machining the parts that were expected of me. If it weren’t for my teammates’ experience and patience to help me, I feel like I wouldn’t have performed as well as I did. My lack of experience also made me feel like I couldn’t help my team that much. If I would have been able to get over this and be more willing to dive right in, I feel as if I would have learned more and been a better help to my team.

Peter's Reflection

One of the junior MEs that went through this class told me that it was going to take up more time than I expected. And to my surprise, he was right, but it was still an extradorinaiy experience, filled with anger, surprise, delight, regret, optimism, and finally joy. Anger. The anger came from the fact that weeks were spent on this project. At some times, other classes and studying were neglected. The time we were given to complete this task was nothing short but minimal. When we were at the design competition, and were awarded the "Most Complicated Design", there is no surprise that most of the time we spent was on a very complex project. Some of the other projects we saw were relatively simple to ours. But being who Team I'm on Top is, we wanted to create something that we were proud of. What we created not only looked like we spent time, money, and creativity in, but it was an effective machine to compete against the best of the competition. To our dismay, we didn't finish at the top, but we hopefully showed that we were committed to being competitive in the slot bot competition.
Surprise. We were surprised to see all the efforts of the other teams. (Especially those who incorporated an impressive design with great machining) In my opinion, this year's machines were far better overall than last years. I was very surprised to see some of the strategies that other teams used. For example, Team Boss's strategy of blocking the flipper and than using that opening to deposit ball from the top, was a strategy that I did not expect. I always assumed that when you block the flipper on the bottom, you should score from the bottom.
Delight. Every time our team got together (which was alot for the past few months), we were always able to get a lot done. We never procrastinated til the last minutes, and we always finished the tasks at hand. A great example of our time management skills was the week before thanksgiving. MS8 was due, and we spent the entire weekend, working on the milestone. We calculated the hours we put into it, and came out to around 36 hours for the entire week leading up to that wednesday. Regret. Although we were able to finish it, I realized that we put more effort into the project than we should have. But thats who we are, we are a team of individual perfectionists, who want everything to be in order and right. If I could do it again, I would have to say that I would have spent more time on the bigger picture than the smaller one.
Optimism. After each milestone was completed, and every part was finished, there was a sense of optimism that our machine would work. Seeing the final version of the CAD file, and then putting that together to form a final product was a great sense of accomplishment. In the end, I knew for a fact that the project was going to be completed, and that we were going to have a great machine to showcase.
Joy. Whenever you spend hours and hours on a project, it can bring a team together. As we were all dressed up for the slot bot competition, we finally saw our machine compete against other machines. There were definitely certain misfortunes that we came across, ie our tracks fell off on the first round! but nonetheless, it was our creative thinking, and our designing process that built that machine, and that is something that I am always proud of. The time we took to find a schedule that works for everyone in our team, as well as get materials for our machine, was something that is vital to any design and manufacturing process. This is one of the most important things I took from the class. If there were certain improvements that I could make to the class, it would be that I would have liked to see more of a lenient schedule. Even though the milestones were created to keep teams on pace, I believe that it is up to the teams to create their own schedule and their mistakes. Therefore, I believe that a team should only be given the problem to which they have to solve and the date at which it is due. I do not believe that MS should have been used because in the real world, it is not a fact of whether or nor a team finishes a certain milestone at the designated time, but whether it meets the overall due date. If a team doesn't finish the project on time, then it teaches them a lesson of time management, more than if a team misses a milestone.
This was one of the classes where I questioned my commitment to being an engineer. But seeing what I can do in the end, made me realize that engineering is the right path for me. (Having a problem and creating a solution) I would like to thank Bob and John in the machine shop, as well as the GSIs, especially Sei Jin Park, and the professors for their part in this designing process. But the biggest thanks go out to my fellow teammates. I had a great semester with them, and can not think of anyone else that I would have been with. Always on top, Peter.

Brad's Reflection

ME250 has been an exceptionally demanding class.  In several ways this was a function of our Team’s ‘bot design (see “Most complicated Design” award), and I understand we brought this on ourselves.

However, the requirements of scheduling shop time, completing milestones, completing labs with homework, blogging, keeping track of all the course communication avenues and data, making videos, scheduling teamwork, going to lectures and labs across campus…this class needs to be worth 2 more credits, should come with a free smart-phone including a ME250-dedicated application, and also several get-out-of-work-free passes for other classes, activities, and jobs.  

Time management has been critical, and I think as a team we were reasonably successful in this realm.  Our ‘bot has been recognized as complex, but as a testament to our time-management we still completed everything on (and even occasionally ahead of) time.  A big thanks goes out to everyone on the Team for not procrastinating…we would never have made it out alive if we hadn’t been on our game every day.  

I greatly enjoyed the design process related material.   Developing creative thought methods is very important.  Ideas on how to capitalize on (and compensate for!) being a very-right brained individual were greatly appreciated.  I crave opportunities to work with a team of dedicated individuals in an environment focused on generating creative solutions to a diverse set of problems, so the presented alternative methods for idea generation and process flow were very interesting.  System-level engineering is a rewarding and natural mode of operation for me; I’m wondering if I should just move back to Providence and transfer to RISD (a joke, although RISD girls are certainly a fascinating bunch). 

Speaking to my tendency to think at a systems level, I would have appreciated more tutelage on the specifics of machine design.  I don’t feel I learned enough about the use of the presented components/systems.  This being a 250-level course I’m guessing (and hoping) there might be a greater focus on such topics in later ME courses, and also projects focusing on specific components.  I also acknowledge that I am a non-traditional student with a background in and deep passion for technology, and my motivations, knowledge base, and desired learning depth are not likely the same as a traditional sophomore. 

As time progressed and I saw the complexity growing I was repeatedly reminded of this chart Professor Hart presented to us:

While we certainly should have been more conscious and avoidant of it I think the ‘bot complexity was a result of the Team’s desire to live up to our team name, and this is a positive thing.  It speaks volumes about our personal expectations and the trust we placed on each other.  Looking back, all I would have done differently is approach system design with a much higher focus on weight optimization.

I’m very glad to have been introduced to 3D CAD, it’s a skill I’ve been missing and wanting to develop for many years.  I wish there were more tutorial sessions on more complex functions available in Solid Works, but I guess that’s what the software’s included help files are for…  The lectures on engineering drawings and tolerance specification were very helpful and the related slides will serve as excellent references in my future projects. 

The production-related portion of this class was huge, and rewarding.  For me it served as a creative outlet, and a much appreciated environment for learning techniques for upping my efficiency and build quality.  I’ve been professionally exploring (and also playing around with) fabrication and assembly techniques for several years and really want to keep expanding my knowledge and skill base in this field.  Learning CAD has been an important step in this!  I really hope I get the opportunity to develop CAM skills in the future.

Overall ME250 has helped me recognize and explore my strengths and weaknesses.  Such an opportunity has not been present at levels this intense and diverse in any other course curriculum. 

Stay On Top,

Brad

Bill of Materials

Bill of Materials

The Final Team Posting

 We've completed our machine and tested her in battle against our peers. The following are some pictures of our completed systems.  A big thanks goes out to the ME250 staff (especially GSIs) for all their advice and votes of confidence, and Bob and John for their knowledge and help in the shop.   




The mobile collection unit in foreground and the slot jammer resting in the back.

The last thing pong and squash balls see before collection!

The sliding hopper door utilizes a rack and pinion gearing system, with a guard over the motor and gearing.

Our undeployed slot jamming device (resting on it side).  You can see the rubber-tipped swingarm which allows us to score slot balls, and the spring-loaded launcher for the main jammer.  Also the aluminum pads which allow the mobile bot to park on top of the system counteracting produced during deployment can be see on the outer housing.

 

This is the slot jammer dfeployed position.  It forces the slot open while a gap in the plastic allows for the scoring of multiple pong balls by the swingarm component.

  

Another shot of the deployed jammer.



A table-top view of the deployed jammer.  Jamming the flipper and scoring pong balls is a 100% repeatable operation
(what whaaaattttt).



A closer look at the ball collection system.

While Im On Top did not progress to the final round of the SlotBotII competition, the system recieved the "Most Complicated Design" award.  While we understand this is a mixed statement, this recognition vindicates the hours of hard, excellence-dedicated work put forth by our four-man crew! 

Bill of Materials

https://spreadsheets.google.com/ccc?key=0AqVvy0w8--M7dExyaElxZjRZR3VCVTAyeng0OW5hVkE&hl=en

Arthur's Reflection

After reading the feedback presented by last semesters slot teams, I knew that this class would require a significant amount of time and dedication. That being said I was still somewhat caught off guard even though the long hours spend working on our machine were probably more due to our design then the layout of the competition. As we progressed through the semester there were feelings of excitement mixed with dread, but in the end I felt that the experience as a whole was worthwhile and rewarding.

In the design and manufacturing phase, I enjoyed the classes on CAD. I had been meaning to learn how to use CAD software for a while now, and the CAD process as a whole was very helpful for designing and visualizing the vehicle. A downside of using CAD was how it made the design process almost to easy, once the vehicle was started in CAD the complexity of the design sort of got out of hand. I believe that our team already had a general understanding of the existence of all the mechanisms covered in the lectures, but the lectures were still useful in the way that they refreshed our memory of all the mechanisms that we could incorporate into our design.

With regards to manufacturing, I believe that everything went relatively smoothly. Our team knew that we had quite a few parts to complete, and we had things planed out way in advance. Problems did still arise such as slight alignment issues with the table, and failure in some of our bought components, but because we had given excess time in our schedule we were able to finish on time. The only thing I was disappointed with was our ability to run practice tests on the table and fine tune things in the end. With only two tables and four remotes with 28 teams though, I’m sure many teams were experiencing the same issue.

Overall, I was very pleased with the strong teamwork in our group. Every time we had a group meeting everyone would show up to the best of their ability. Rather then assign set roles, group members would step up and take on certain tasks. The rest of the group would then discus and critique the result so that we would have a solid finished project.

If I were to redesign the machine, I would make numerous changes. Our design was focused around the fact that we would gather up all the balls on the top of the table. In hindsight this is an incredibly unrealistic feat to accomplish in 90 seconds. Overall, the strength of the machine’s components were significantly stronger then they needed to be. This lead to a heavy vehicle with a slow rate of translation as the double gearbox was unable to over come this. Despite the disappointing performance by the double gearbox, I was happy with the performance of the flipper and the hopper release. The machine easily gathered up all three types of balls if only we could get the vehicle to them.

With regards to the competition, there were a few things that I thought could be improved upon. Most of the teams could have performed significantly better if they had a week of testing to make slight modifications to their machines. In addition I believe that the overall time of the competition rounds should be lengthened. When I first envisioned the game, I thought that most of the balls would be collected. Except for Team Boss which had a very effective and well built design, no other teams came close to bringing in large amounts of balls.

Video Introduction

Here is our introduction video for the competition!

This will be the last thing enemy bots will see before they fall in competition....

Final Week Until Competition

The last week of school is on the horizon and with that our completed assembly. Thecompletion of our project was to a great relief as hours and weekends were spent to complete this for the slot b0t competition. We did however come across many bumps within this past week. One of them had to do with the drop bar. As we tested it on the tables found in the machine shop, we noticed that the tables were not designed equally. In particular, the slots of the tables were not the same. one was measured to be 2.33 inches wide, while the other was found to be around 2.4 inches. The reason forthis major difference was blamed on the warping of the plexiglass. Due to this warp, the slot was smaller than it was previously designed. This big difference affected how the slot jammeroperated in the slots. With a smaller space, it was difficult to install the slot jammer within the 2.33" wide slot. However, our slot jammer operated easily within the 2.4" wide slot. After talking to the instructors and GSIs, we were told to modify our design to fit the natural variation seen in any design. Therefore we came to the solution to cut the entire slot jammer in half and weld it together in order to make the widthsmaller.

Another problem that we came across had to do with our track wheels. With the enormous amount of torque that our double gearbox produced, the shaft filed down the inside of the wheels and were unable to grip onto the shaft. We came to a solution that involved clamps, in order to deform the plastic onto the shaft.

Even with all of these set backs, the assembly fit together, and we were able to have a completed assembly. A net was constructed to contain balls within the hopper as the flipper motor was observed to be powerful enough to flip the balls over the hopper.