Kyle's Reflection

Since I am a junior in Mechanical Engineering, I know a lot of people who have taken this course, and the reason i did not take it last year was not entirely because i transferred in from LS&A my sophomore year. The workload i had heard this class would need from me scared me away because i thought my schedule was too hard at the time. As the class started, I realized that this fear was real, and that this class would require a lot of work. What scared me the most was that I did not have a clue what i was doing in the design and manufacturing area.

Once we got our teams together and I realized that my teammates had a lot of experience with design and manufacturing, I was intimidated and excited all at the same time. Between class and work with my team mates i was able to learn a lot about design and manufacturing. I also realized that i have a lot of good ideas about design, and that i just don't know how to apply them into manufacturing. Throughout the semester I learned a lot about manufacturing, and how to work as a team and make something great.

Never have i been under such strict time constraints for such a large project. Everyone on the team needed to bring a lot of effort to the table during manufacturing and with so many things due so often we had to meet very often and provide strict timetables to get everything done. This was a great learning experience for work in real life.

As a team i think we had a lot of fun and building our robot and competing with it was a lot of fun. Seeing all of our hard work perform, and quite well, i might add, was very reassuring and cool. The competition part of the class was very cool, but I think there should be more benefits for doing well.

Also, I do not believe that the motors were powerful enough to be effective with some of the more creative machines, such as ours. Even at the highest gear ratio, the double gear motor did not provide enough power for our machine to move around effectively, even though our machine was not that heavy.

Although this class provides a lot of good lessons and helps people come together for a common goal, I believe we wasted a lot of time in the beginning of the semester coming up with individual ideas that did not pertain in some cases to anything we would work on later. Also, I think we should have had some individual projects to manufacture something on each type of machine (i.e. lathe, mill, band saw, drill press). I think this would help tremendously because if students like myself come in without any knowledge of the machines, they end up only being able to do work on a couple of machines, especially since there are such strict time restraints. I know this was the case when I was doing work on the machine and i'm sure that other students feel the same way as I do.

Final Team Documentation

Our final design consisted of four main components. First the main component, the harvester. The harvester ended up similarly to how we originally designed. We changed from 3 paddles to 2 paddles after testing the sketch model. Our final model finished with 2 paddles. These paddles were made of acrylic and delrin spacers, with aluminum axles connecting the harvester to a planetary motor. The acrylic and delrin were laser cut and the aluminum was turned down on the lathe. The harvester can be run forwards or backwards. The harvester design and manufacturing went well with minor issues with the axles. In the end the harvester performed well in competition and was getting enough power to successfully pull in balls.

Second is the frame, made out of 12"x12" aluminum plate and the 1"x2" aluminum. The 1"x2" aluminum was shaped using the bandsaw. The aluminum plate was cut on the water jet and the waterjet moved it during cutting, which changed most of our holes by 1/8". While putting our machine together we had to file and drill these holes to size so everything would fit. We added the slanted bottom from our original design and it worked well with the trap door. This part was also waterjet, and turned out well. One big issue we had with machine performance was the bent metal at the front which was not quite at the angle we would have liked due to the shift during the water jet. The frame connects all of the other components. The frame is almost exactly how we originally thought it would be.

Third is the trap door, which in our original design and sketch model we were unsure how the trap door would work. In the end we decided the put a roughly 3" diameter hole in the back of the frame and attach a laser cut piece of delrin to a motor and rotate it about the bottom to let balls drop through the bottom. Attaching this to the bottom of the machine was a little bit of an issue, but only a small one, especially in comparison to the other issues we had with holes matching up.

Last are the tracks and drivetrain, which we originally designed so we would have a 0 turning radius. We waterjet aluminum for the tracks to screw into the frame on both sides. Attaching the tracks was not a problem, but in practice the tracks would not stay on well when turning too much. Also, turning did not become much of a problem for us, due to the fact that the motors did not apply enough power for our machine to move very quickly even at high gear ratios.

Overall, our machines design and manufacturing went well, and we had a great start with a functional sketch model, and from then on out we did not have to change much from our design model to our final robot. This was very helpful for our team, so we only had to apply minor changes to our original design.

Bill of Materials

Laura's Reflection

Before I began ME250, I was warned by numerous people that the class has potential to take over your life; they couldn’t have been more right. From the first lecture that outlined what we would be doing and learning, I knew that this class would take more work and dedication than my other classes. Despite the extra work and added stress, this class was very valuable to me and taught me many things that I will continue to apply in my engineering curriculum. I learned many things on teamwork, design, manufacturing, and how achieve a goal within a time budget.

On teamwork, I learned that dividing and conquering is the best way to go about a task when resources and time are scarce. Often I would come to lab with my team and each of us would be assigned our own task. At the end of lab we would come together again and re-evaluate what needs to be done before the next milestone. If necessary we would schedule a time to meet in order to make the requirements for the next due date, with each of us contributing something. As a team, I think we worked well together. Each of us had our strengths, so we assigned each task accordingly. We did have to work around a split team however, Cole was in the lab section before the rest of the team, so it took some extra communication to have a productive lab. Despite not being able to work entirely as a team twice a week, having a team in two sections was very beneficial from a manufacturing standpoint. We only scheduled machining time outside of lab twice for the entire project. We were very thankful for this due to our busy schedules. Overall, as a team we worked very well together with everyone contributing what they could and making sacrifices accordingly.

From a design standpoint, my knowledge in design in general increased greatly. I thought that the FRDPRC tables as well as the comparison charts were very beneficial. They are a logical way to make a decision. I have even started incorporating them into other aspects in my life (design decisions for BAJA SAE as well as major life decisions that need a logical foundation). The way designing something was broken down in lecture was also very helpful; it made this huge, mind boggling problem shrink down into something more comprehensible. It also allowed me not to get overwhelmed by the project and to take it one step at a time. I also enjoyed learning a different CAD program. I am on the BAJA SAE Team where we use CATIA. It was helpful to see the benefits and differences of each program. I think that Solidworks is a very good program to learn on and I thought that the tutorials were very helpful. As for the design of our robot, it was very interesting to me to make a decision as to what we want our “bot” to accomplish and then see it in CAD, step by step. The entire design process of our “bot” also helped me decided what I want to do with my life, whether it be manufacturing or design/product development. Seeing our robot go from rough ideas to a working CAD model made the decision clear for me that I should be tailoring m education towards design.

In the manufacturing of our “bot”, I became more familiar with the machines. Through BAJA, I have already had experience on the mill and drill press, but through this project I became more comfortable using these machines and familiar with the lathe. I also learned how to use the water jet and laser cutter. It was good experience to have machine parts and then have them line up accordingly in order to assemble our robot. We ran into a little snag when the water jet shifted our base plate by about an eighth inch. We had to re-drill some holes and fix a few parts in order to get everything to assemble correctly. However, once we did, it was very exciting to see a working robot that we designed and built.

Overall, this course was a very good experience. As stressful as it was, it was good to have the experience of a big project in a short time budget. For future classes, a more involved machine shop training would be very helpful as well as more available machines. I spend a lot of my time in the Wilson Center for BAJA and I saw many teams using the tables there because of the chaos in the ME shop. And even with my previous machining experience, I thought that the training just touched upon what we needed to do. Another helper in the shop would also be incredibly helpful, especially considering the number of people who have never been in a shop before. It was truly wonderful to see our robot go from the drawing board to coming in 4th at the competition. Thank you so much for making that possible!

Ethan's Reflection

I learned a lot about myself, engineering and manufacturing in ME 250. As a member of the Solar Car Team here at Michigan I have learned a bit about the design process, but not as much about the manufacturing process. ME 250 taught me a lot about this process. This class was informative because it was a good combination of both the theoretical side of engineering and the hands-on, practical side. Before taking this class, I had experience working with wood, but I had never made a part from metal, let alone on a mill or a lathe.

Previously, the experience that I had on the Solar Car Team was on the operations division, and had never worked with CAD or experienced the design process. Taking this class helped me become a more important member of the Solar Car Team by teaching me about this process. Learning SolidWorks enabled me to put my thoughts into tangible items.

Along with this, this class enabled me to take something from thoughts and ideas to a CAD model and even further to a completed item. Seeing, and being a part of this process was thrilling. Not many more classes at the University will allow me to do something like this again.

Furthermore, I learned a lot about myself in this class. There are always ups and downs in any project like this, and it is important to keep your head up and help others on your team to do the same. A group cannot go forward without all of the members of the team. I think it was also important that one of the people in our group really stepped up and took over the team. Even though our leader wasn’t a formally elected entity, it was important to have a person to go to make sure everything was in line and to keep us in line as to what needs to get done and when.

As for the class, I believe that starting the design process sooner would be nice for the class. It seemed like we had to decide what our machine was going to be very quickly. There was not a whole lot of time available to “sleep” on ideas we had discussed. I believe more time would have been nice. In addition, I wish that I would have looked at other team’s designs in the previous years to get a better idea as to the amount of power the motors had. This was the fundamental design flaw in our robot.

One concern I had was the manufacturing of the each of the tables. I know that it was hard for some teams to execute their robots due to the minor discrepancies in each of the tables. One team in particular designed a machine based upon the CAD model and it fit in one of the tables and not the other. Based upon our robot, one of the tables had more balls in the middle of the table that were closer together. Due to the lack of power in our motors and the way we had to play the game, it would have been advantageous to play on the other table. This needs to be fixed for next year.

Finally, I disagree with the way that “ties” were handled. I believe that something better needed to be done than whoever pushed the flipper over wins the game. This was to our disadvantage, and luckily never harmed us, but I thought it was unfair to the teams that could have scored had they beaten them to the flipper compared with the teams who were fastest to the flipper but were unable to score. Some sort of play-off could solve this.

In conclusion, I had a good time in this class and had a great group to design a robot with, but fourth place? I’m disappointed that I stayed for 3 hours to beaten just before the podium. In all seriousness, this class was an overall great experience and will help me in the future.

Cole's Final Thoughts

I came into ME250 expecting it to be quite an involved class after talking with multiple students who had taken it previously, and boy were they right. Even though I have had a fair bit of design and manufacturing experience coming into this class, I have never been held to such a rigid and fast paced timetable. It seems like just a couple weeks ago that we were sitting down in the computer lab to begin the design of our machine. I am used to setting my own schedule and working at my own pace, knowing that I have a final deadline to meet and that I can work backwards from that point. This class though has taught me what it will be like working in industry where there are intermediate deadlines and goals throughout the course that are out of your control. The other biggest factor in our team’s time management came from the fact that my schedule was different from everyone else’s due to being in a different lab section; because of this, we had to make the most of the little time that we had as a full team. When we were able to meet as a full team, we had to be sure to stay on task in order to complete the things we needed to do in the time we had. This scheduling challenge was not as bad as it was initially made out to be though; and in the end I feel that it actually benefited our team. There are times in the design process where you want a large group, to be able to collaborate and brainstorm ideas and bounce concepts off one another, but there come a point where that large group dynamic begins to hinder design and becomes a burden. Once we had nailed down our concept and how it was going to work, it was much easier to sit down with only part of the team and design the nuts and bolts and fine details of the robot; its not possible to have four people trying to decide the location of a hole, and the design process ends up being much quicker when it is headed up by one or two people.

When it comes to the manufacturing of a design though, things get much more interesting. I have done a bit of manufacturing in the past, but nothing on the scale or precision of our robot. Being able to get hands on experience with amazing tools such as the laser cutter and water jet was one of the highlights of this course for me. Although our design was fairly complex, we took advantage of the precision tools that we had access to (laser cutter and water jet) to manufacture our most complicated parts so that the building of our robot was similar to the assembly of a car or some other pre-fabricated machine. Even with this simple approach though, we encountered unforeseen obstacles that added to our assembly time and set us back slightly. I learned that you can’t always count on holes to always line up, and that metal is a lot less forgiving then other materials such as plastic or wood. There were multiple instances where holes in our parts were correct when aligned with one other connecting part, but when the entire assembly was put together there was just enough misalignment to require re-drilling the holes. I also learned that even with computer controlled machines you can have make errors that affect your entire project. While we were water jetting our main base plate, the material shifted by about an eighth of an inch, changing the perimeter features of the design. We were able to overcome this issue with a slight modification of just a few of our parts, but it just goes to show that everything can’t go as planned.

One of the biggest things that I felt was lacking was an introduction to hands on manufacturing during the first part of the lab section. Our first opportunity to manufacture real components was with our own designs, which may not lead to the best first experience. A large portion of the design process comes from knowing what can and cannot be manufactured and how the machining process works. If machine training was taught before or concurrent to design, I think it would be much more beneficial and lead to more robust and well thought out designs. The digital world of CAD does not always transfer easily to the real world, and I feel that there is a lack of emphasis on that fact. My other concern is in regards to the electronics provided in the kit. Although it is useful to be able to choose the output gear ratio of the motor, the motors proved to be quite weak even with high gear ratios. I feel that the demand on these motors grows with the complexity of the problem to be solved, and that the current problem to be solved requires more powerful motors.

Overall I am pleased with my performance in this course, but I feel that the greatest thing that I could have done was stick to a stricter personal schedule. Even though we had deadlines and assignments throughout the design process, I feel that I could have been more productive and successful if I had set machine goals to stick to. Basically by saying what components I wanted functioning by a given date, I think our fabrication and assembly time could have been put to better use, and allowed us time to troubleshoot our robot in more depth and possibly solve our issue of underperforming motors.

Competition Video

Here is our video for the upcoming slotbots competition. Be sure to stop by and check things out on Thursday.