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.

It is Official.

Our final assembly.

Today we were able to finish the final assembly of our robot. After weeks of manufacturing and fabrication, our hard work finally payed off as we hooked it up to a stationary power supply and it came to life. There have been a few obstacles along the way, but our perseverance has payed off as everything has come together. All that remains now are the final tweaks required for mounting the control box. Then we wait for the final competition were we will see how we stack up against the rest of the competition.

Without further ado, here is the first video of our robot in action.  

The Harvester is Complete!

Earlier this week we were finally able to fully assemble our most critical module (the harvester). Over the past two weeks we have been manufacturing all of the parts necessary for this module, and on Tuesday afternoon all of our hard work payed off as we were able to assemble the harvester with relative ease. Thanks to the high tolerances we were able to achieve with the laser cutter, our press-fit parts were able to attach quite snugly and provide the solid structure that we need.
In addition to the completion of the harvester assembly, we received approval on the remainder of the engineering for our robot. With this clearance we are stepping manufacturing into high gear this week, finishing the remainder of the frame rails, and water-jetting the final parts of our robot on Thursday.

The final Harvester assembly, ready to be attached to the frame of our robot.

  

Manufacturing Week 2

This week we finished turning the axles, and laser cut the supports for the harvester. We also finished laser cutting the supports that hold the paddles onto the axle. We used the bandsaw and drill press to work on the motor box. It is almost complete and is only missing two holes. The axles were 1/4" aluminium rods, the supports were made out of acrylic, and the motor box was made out of 1"x2" aluminum. We also water jet cut the supports for our tracks, which came out well besides a couple of malfunctions by the water jet where it did not fully cut holes.

Since the paddles are already made, our MCM, the harvester, is almost complete. This week we are drilling holes in the gears for set screws and finishing production on our MCM. We will be putting all the pieces together for the harvester this week and making sure everything fits just right, and making adjustments for anything that does not. This will be done before MS8 on wednesday.

Next week we intend to build the frame out of the 12"x24" aluminum plate and the 1"x2" aluminum. We will also finish holes on the supports for the tracks where the holes were not fully cut. We also intend to start work on the trap door portion of the frame so we can release the balls.

Manufacturing Begins

This week, we, the Ghost Robots, began building our robot. We are starting with our most critical module, the harvester unit. This unit is composed of four different components that may need to be manufactured multiple times. Of these four components we have completed the delrin paddles and began turning the two 1/4in aluminum axles. We used the laser cutter to cut the delrin paddles. It took forever to etch the text into the paddles, but it was worth it, they turned out very well.

Cutting two paddles

took about 36 minutes.

The paddles are etched

with "GHOST ROBOTS"and

are used to sweep ping pong

balls into the machine

Next week, we intend to finish turning the axles, and use the laser cutter to cut the supports for the harvester and the supports to hold the paddles onto the axle. Each will be made from acrylic so once everything is set up it shouldn't take long to finish.