Individual Reflection

The ME 250 project was a long process. From the brainstorming to the last screw, the project was stressful. This class was very helpful in understanding how an idea evolves from a thought to a physical machine that completes a task. The biggest thing that I learned from ME 250 was how to effectively manage time and money. There were only a few short weeks in which we had to take our final concept and manufacture it from scratch.

There were a few difficulties that we encountered along the way. I think that the most frustrating part of the project was the inconsistencies throughout the semester. Not only were there multiple MAJOR rule changes, but there was also a lack of enforcement of these rules during the day of the final competition. These rule changes did not allow us to continue the design process on one specific design. We were continually starting from square one as we were repeatedly told that our idea no longer was legal. Another struggle that we had with the course was the fact that we were a three man team. I know this is not the fault of anyone of the course leaders, but the absence of a fourth member made the entire project very stressful on the three of us. We were responsible for picking up the work load and this often meant missing other lectures or spending extra hours in the shop. I personally also had trouble with the analysis of the manufacturing. I have been in a shop before, but had never been accountable for the selection of materials of the testing of those materials. This class taught me how to choose materials and machine those materials based on specific guidelines and regulations. I found it very useful in this course to learn about the engineering behind manufacturing and the physics which are used during the design and manufacturing process.

If I were to change something about this course I would recommend that the slotbots game not be so sophisticated. The game was very complicated with a lot of rules. These complications led to many teams not even being able to score one ball come competition day. Also I would be much more strict in enforcing the rules that are finalized. There were many robots in this semester that did not follow the rules on competition day and should have been "eliminated after the first round of competition" yet somehow they were able to continue and in one case even win a substantial amount of money. One last thing that I would consider when designing next years course is more manufacturing time. The learning of mechanical essentials is vital for the course, but I believe that many teams would have been able to design and build more effective robots with two more weeks of manufacturing time.

I am very proud of the work that my team submitted. If i were to find an area that we could improve on it would be practice. Had we been able to complete our robot in a shorter period of time we would have been able to practice driving it and would have been more effective in the competition. Overall I think ME 250 is a great course and could become an excellent course with minor adjustments.

Final Machine

Our machine has evolved significantly as the semester has gone on...

Slot module
This module uses paddles powered by planetary motors to move balls toward the flipper and under the wedge. The current design has the motors mounted on top of a wooden frame which hangs from the table in the slot. These motors drive belts which turn paddles mounted on a rigid axle near the bottom of the starting zone. The paddles are at right angles and are different lengths to conform to the slot starting zone.

Compare this design to our original idea of a slot-mounted aluminum frame. Changes in the design were a result of budget constraints and rule clarifications.

Wedge Module
The wedge remains largely unchanged from the initial stages. It still has the same function: block the flipper and let balls under to our bin. The first main difference is the notches in the lower part of the wedge, which keep the wedge in, should the bumper be pushed from the other side. The second difference is the brass tips on the wedge, which create a denser lower half, keeping the wedge oriented vertically as it falls. The third difference is the pair of notches used in conjunction with the release mechanism to make a clean release. These changes are a result of tests and design insights.

The original model was a solid piece of aluminum, which would have been difficult to make and ineffective in play.
Top Bot

The top bot remains almost completely unchanged, and is our best-designed and most robust module. It is used to displace balls defensively and can collect them as a backup offensive measure. Any changes in the design were minor and took place early in the process.


It has been a long, frustrating, busy, FUN semester!!!! We learned a lot and built a functional robot... gearing up for 350 next semester

Last sign off,

-Team MA

Stephen Lanham: Individual Reflection

This ME250 class was like nothing I’d experienced before. Coming in to the class, I had never used any CAD software or set foot in a machine shop. Needless to say, I learned many new skills in this class, all of which will help me throughout the rest of my engineering career. The experiences I had while familiarizing myself with these fundamentals of engineering resulted in a very positive experience overall.

The first learning curve I encountered was sharp: having never used any program remotely similar to Solidworks, I was very lost during the first few lab sections. I found myself having difficulty translating the ideas in my head into geometry and constraints on the computer. However, after taking some extra time to fiddle with the program, I quickly discovered just how intuitive Solidworks really is. I can recall a specific instance, in fact, when everything clicked. From there, it was just a matter of figuring out the depth of the program. Of course my future engineering applications will not all use Solidworks, but in a field that is becoming more dependent on computers by the day, even this small introduction to CAD is helpful. For my next design project, I think I will better utilize the CAD program to test my design before I start manufacturing. My use of it this year was mostly restricted to creating drawings for the shop, but I have learned that it is better to use the computer to model than to have to build, redesign, and build again.

Machining was something I also hadn’t done, so I wasn’t sure of what to expect. It turns out that I enjoyed manufacturing more than CAD modeling, but it also offered many, many more headaches. I have always liked to work with my hands, especially with wood, but this class exposed me to a whole new level of machining. Precision, tolerances, tools, tool and feed speed… I learned that in the machine shop, you have to account for all of these factors and more in order to get the piece you want. I also learned that if multiple parties were designing and manufacturing, ideas had to be laid out completely explicitly in drawings, or they would certainly be interpreted incorrectly. If there are limits on materials or time (which there always are), this creates a serious issue. In the future, I need to remember to devote more time than is necessary to the machining of parts. It was frustrating to be making a part on a tight time limit, something which never turns out well.

Although I have worked in teams before, this class presented a special challenge. The combination of all the stress, the crazy travelling schedule our group had this fall, and only having three team members made this a uniquely difficult class. Luckily, all members of our team were involved and dedicated to success. This created an environment where we consciously let our strengths compliments each other’s, and strived to hit all goals efficiently. Being explicit when communicating ideas was a struggle at the beginning, but we learned and adapted as the class went on. This class has convinced me that on future projects, I should designate stronger team roles and more rigid schedules at the beginning of the process, so that there is limited confusion in the end.

I do have a few suggestions for next year’s class. My primary issue is that although the staff were clear on the goals of the class, they were not always clear to the students about what exactly was expected, what was an acceptable manner of achieving our goals, and what we could expect from them as the facilitators of the class. The several rule changes throughout, a solid model that did not reflect the true dimensions of the arena, and subjective differences between the lecturers and GSI’s all made for a very confusing design process. These issues did not create an insurmountable goal for the teams, as all of these problems can be easily solved, but a little more organization would have been nice, especially because that is what is expected from the students. I suggest perhaps simplifying the game for next year, so that it is not necessary to put so many constraints on the rules. Otherwise, the class was run in a fun and interesting manner, and was a GREAT experience overall.

Final Bill of Materials

Our final Bill of Materials can be found here:

https://spreadsheets.google.com/ccc?key=0AnEPq3yyX7WTdHZaVUZKRXVjREJ2LUREM0U1QllqbWc&hl=en&pli=1#gid=0

The parts that we purchased are highlighted in the Bill of Materials, but are explicitly listed here for convenience:

https://spreadsheets.google.com/ccc?key=0AnEPq3yyX7WTdHhVMUFDc1BDMGtpYzZiUDllS3dPSEE&authkey=CNHw4HU&hl=en#gid=0

Josh Getz: Individual Reflection

ME 250 was a class that certainly required a lot of time and effort. The course aims to have students learn the basic concepts of design and manufacturing, and then apply them to create a working robot that plays a game that we all know and love, Slotbots.

I had never really “formally” made anything. Meaning that I’ve certainly built my fair share of things, but I’ve never gone through the engineering process the way we did in this class. I’ve learned that when faced with a daunting task or given a large project, the first thing to do is step back, and look at the whole picture, and break the problem down. Ask what are we trying to do, and what are the parameters that need to be met? Then continue on to ask how are we going to do this? This is followed by brainstorming and the selection of a concept. Essentially I’ve learned the value of the funnel that Professor Hart talked about in lecture. Start big with strategies, and then work your way down to small components, and how all the pieces interact with each other. The amount of detail, and the importance of selecting the correct tolerances and materials was often the difference between success and failure of the robots that were built. The effort spent keeping drawings and CAD models up to date, and accurate down to the washer may take longer initially, but it saves hours of time spent remaking parts that were made incorrectly because of an unclear or mislabeled drawing. The knowledge of what each tool can do, and how to use them properly will not only allow for a better part to be made, but you will learn more about what the best way to go about making the part is. The most important things I’ve learned about design and manufacturing are the need for accurate drawings, and a full plan of action before diving into a project as it will save time, money, and result in a higher quality, better overall product.

Building a slotbot is certainly not a one-man job given the time frame. Members of teams needed to depend on each other in order to be successful. It is important for all members of a team to fully understand the project, but they do not have to be an expert in every aspect of the project. The key to a successful team is leadership, and dedication of the members. The leader needs to recognize the skills of the members and utilize them to their maximum potential. The leader also needs to keep everyone on the same page, working together towards a common goal, as well as keep the team to a schedule. The schedule may need to be constantly updated, but it is important to know what has to be done when, and how much time can be allotted to different tasks. Members must be able to trust the work of other members, which requires the dedication of every member. It is also important, especially in the design stages, that nobody is scared to say what is on their mind, even if they think it isn’t a good idea. When a member is struggling with a task, the other members need to step in and help.

I believe my performance could have been better if I was slightly more on top of the material. I was so eager just to build, that I didn’t take enough time to really learn and apply the design concepts from lecture. Despite this, all of our modules were functional, and well constructed. The fundamental problem in our design was the robustness of our two modules that were in the slot. We relied on gravity to deploy our wedge, which, once in place permanently locked the flipper in our favor. However it was difficult consistently get it to fall into the correct place. It would have been a much smarter idea to use a giant hollow wedge that extended all the way up the slot, as several other teams had. The primary reason in our poor performance in the competition was more a result of lack of practice operating our modules, as all our modules functioned as they should (outside of the wedge deployment). Another thing that I could have improved was the schedule. We loosely stuck to the schedule, and seldom updated it. We got everything done on time, but at times it was slightly unorganized resulting in inefficient use of time.

This course was quite frustrating overall. Frustrations began with the rule changes. I was part of a three member team, so we were already pressed for time, and literally every rule change required that we completely redesign at least one module of our slotbot, nullifying hours of CAD, sketching, and brainstorming. It wouldn’t have been such a big deal, however there were at least three rule changes that were in no way a “clarification” after the rules were supposedly set in stone; the biggest of which were the constant starting zone adjustments and the new last minute ball configuration. What angered me even further was the fact that hardly any rules were actually enforced during the competition. Nearly every team was outside of the starting zone “The zone measures 24" along the slot (starting at the edge of the ball retainer) and 24" perpendicular to the slot.” Rule C-1. But an even bigger issue was the fact that the team that got second place did not meet the size requirements of the robot as stated in the rules “Your entire machine must fit in a box no larger than 12" x 12" x 24", and yet somehow they walked away with $200 despite rule B-3 which explicitly states “Machines that exceed the size and/or weight constraints must compete, but are not allowed to win.” I don’t know why it was decided that the rules would not be enforced but it was certainly not a fair competition in any way. There were far more rules that were violated by many teams that I don’t want to go into now, but I am disappointed in the standard withheld in the competition. Despite the lack of rule enforcement, I did learn a lot in the class, and I think that this version of ME 250 is a great class. I would recommend either changing the rules to those that can/will actually be enforced, or making the game a little simpler. The game this year was far more complex that it was last year, which is why so many teams failed. Another suggestion would be to give teams perhaps a week or two more manufacturing time, which will allow for more design flaws to be worked out and hopefully result in a more successful competition.

Overall I enjoyed this class. It was very interesting and fun to see an idea come all the way into full functionality in just a few short weeks. I am looking forward to 350 in hopes to apply what I’ve learned from this class, and improve in my performance.

Check out the team video

Enjoy

-Team MA

MS9 complete!!!

After some hustle and bustle on Friday night and some modification over the weekend, all of our modules are functional and ready to go for MS9. The functionality of each module is good, however there are still tweaks to be made in the slot module and the wedge.

Issue #1: Unfortunately, due to the fact that when we originally tested the wedge, the weight on the flipper was not accurate, the wedge is not sliding down into place like we had hoped. However the firing mechanism is functional.

Issue#2: The flippers tend to run at slightly different speeds, causing them to come into contact with each other. There is team discrepancy over the way we should handle this. It may be the best to trim the paddles, seeing as we don't need to focus on the squash balls.

However, we have Monday and Tuesday to deal with these problems, which should be within the scope of what we need to do.

Pushing it to the wire,

-Team MA