epic battle

Anna Brieland-Shoultz: Reflection

My first impression of ME 250, after our first class in September, was, “Wow…this class may actually be a lot of fun!” It did prove to be fun, but it was also a tremendous amount of work. The most important thing I learned from ME 250 didn’t have anything to do with design or manufacturing, really: ME 250 taught me how to manage my time and keep track of many deadlines. Along with this, the class also taught me much about the design process, manufacturing and machining techniques, and teamwork. All of these skills will be invaluable to me in my future work as an engineer.

I never realized how important time management really was until I found myself responsible for all of my ME 250 assignments as well as three other classes worth of work. With so much going on, I really had to learn how to schedule my time such that all assignments were completed by their due dates. Also, as is common in such things, my team (and myself, individually) managed to waste a lot of time in our design and manufacturing process. I can remember days when we’d spend four or more hours in the machine shop and, upon leaving, reflect that very little had actually been completed that day. As we gained direction in the project, though, and understood what exactly we wanted to machine and when our project needed to be completed, we were able to better manage our time. I learned that the worst thing that we could do, as a team, was approach a team meeting, design session, or machining time without a plan of action. Having a list of daily/weekly goals, along with our calendar of important due dates, were all very good ways of making sure that our work was all completed on time.

My favorite part of Design and Manufacturing was learning how to use the machine tools to make parts which were reasonably faithful to our engineering drawings. There were many tools that I had never used before (ex. lathe, waterjet cutter, and laser cutter) and I therefore much appreciated the opportunity to learn how to operate them. While working in the shop, I learned the basics of machine set-up, operation, and proper tool usage. I also learned that the most important thing one can do while learning a new skill (like how to use a manual mill safely, for example) is to ask informed people for help. Bob, Marv, John (the auto shop guy), and a few ME 450 kids were very helpful and willing to share their knowledge. I have always been particularly interested in manufacturing, along with any type of hands-on work, and knowing how to use these shop tools is a very useful skill.

Teamwork was pivotal to our success in this project. I believe that I lucked out in regards to my teammates—we worked well together, worked well separately (for the most part), and managed to get along even towards the end of the project, when tempers and sleep schedules got a little frayed. Working on this team helped me to improve my communication skills and interpersonal skills. Coordinating our different schedules was difficult, as people were generally very busy but busy at different times of the day, but we managed to make it work. My team was also able to pick up some of my slack the weeks following the death of my grandfather. I don’t think I would have been able to make it through the early November part of the class were this not the case. I never thought that I could appreciate having a team so much: I had been accustomed to working on teams where only one or two people completed all of the work and everybody took credit for it. Thankfully, this was not the case for my 250 team: people played to their strengths, but everybody worked hard.

I believe that this course could have been improved by having ME 211 & 240 as prerequisites. Having taken both of them prior to taking 250, I believe that my knowledge base from these two classes helped me out a whole lot, at least for completing the homework. I also suggest that a rulebook be made available well in advance to the start of manufacturing. Ideally, a rulebook for the game would be made available to teams before they start designing their machines. It was very frustrating to have machine ideas invalidated by particular rules that didn’t appear until well after design completion.

In regards to myself, I believe that I could have improved my performance by staying later in the shop and learning more about the analysis of machine components. I did a lot of machining and a lot of part simulation in Solidworks, along with creating machining drawings, but didn’t learn much about structural analysis. I also had a few days in which I didn’t make it into the shop for team meetings. Apart from feeling guilty, I believe that it’s important for all team members to attend as they are able. Making decisions is easier when all voices are heard and informed debate can happen. Generally, though, believe that I performed pretty well in the course. My team’s machine also worked as we expected, and I don’t think that I can ask for anything more than that.

Daniel Ostrowski's Reflection

Over the last semester, this ME 250 class was very challenging, but very rewarding at the same time. I learned a lot about the design and manufacturing process in addition to honing my teamwork and time management skills in a design project that was much like a real world situation.

The most important thing that I will take away from this class is how engineering/design interacts with the manufacturing process. I learned (through my own mistakes) that it is very important and much more efficient to spend more time on designing correctly than it is to manufacture a part and then later realize that it needs to be modified. I also learned (again through experience) that it is absolutely imperative that a designer makes clear, concise engineering drawings in order to expedite the manufacturing process.

In addition to the design process, I also learned a great deal about the precision manufacturing processes involved in machining. Before this class I didn’t even know that laser cutters and water jet cutters existed; now I know how to use both quite well. Learning more about the limitations and capabilities of other manufacturing processes (such a milling and turning) will help me in the future, as a designer, to design things so they can be efficiently manufactured.

The design project portion of this class required a lot of team work and I learned some valuable lessons from the experiences of my team. First of all, working with others is always a challenge as you learn your teammates strengths and weaknesses and how to effectively communicate with them. Secondly, it was very difficult for four different people, with different lifestyles and schedules, to come up with times where we could all meet and work together. This led to an uneven distribution of workload, which put us too far behind schedule.

Falling behind schedule due to a lack of man hours spent on task caused our design to suffer in the end. Due to this poor time management, we had very little time left at the end for testing, redesigning, and improving. It also caused us to skimp on some aspects (particularly in the robustness and aesthetic areas of our design) in an effort to just get it finished in time for the contest. Looking back on our methods, there were several ways that we could have managed time better. In addition to designing parts correctly the first time, we could have been more decisive during our initial design phase. Several times during idea development, we wasted time by simply not being able to make a decision on things from the overall concept, to what materials and sizes to make our parts. On the other hand, I can cut us some slack since this was the first ever design (and manufacturing) class for all our team members. As long as we can learn from it and become better in the future, it was all worth it.

Speaking of being worth all the work, when we finally got our machine finished (though not perfected) it was a huge relief. It was very rewarding to see that all our hard work and time had gone into creating something that worked very closely to what we had planned.

As previously mentioned, this class was very rewarding but time consuming. Seeing as it is the first ever design course for most students, I was surprised by how rigorous it was. Several times I felt overwhelmed (especially on homework - maybe 211 and 240 should be prerequisites) but I got through it with help from the GSIs. Also, at times, I was very unsure about what exactly was expected from me (homework, exam), so in the future it may be good to be more specific on certain things. Even though I learned from having a tight schedule, I believe it may improve the overall class experience if there was more time for designing and actually working on the project (maybe choosing teams in the second week would help).

Overall, I enjoyed this class and did pretty well. I could still have improved my performance in the class by studying the lecture notes more than three days before the exam. Also, I really underestimated how hard the exam would be, but again, it was another learning experience.

Machine Description

The Cleansweep 7 machine concept is a robot intended to lower an arm into the slot, and then use this arm to push and lift the ping-pong balls into the opponent’s side of the arena. In order to achieve this functionality the robot consists of a chassis, driven by a dual gearbox, an arm that is moved via a rack and pinion mechanism, and a “finger” which is driven via a pulley located within the arm. The arm is raised and lowered by a lift system that constrains the arm via slots “pins” made of 2 blocks of PVC. Aluminum plates bolted to the PVC helped to keep the arm from deforming and popping off the plates. Ball bearings were used to support the axle that housed the pinion gear, due the high loads placed on the axle. All the mechanical elements performed as expected at the point of the competition.

Alterations to the original design included the aluminum plates bolted to the PVC, The method of fixing gears to the shafts, and the coupling of the dual gearbox motors to their drive axles. The aluminum plates were added to the design after it was realized that the arm, although already supported, could deform enough to pop off the constraining pins. The plates not only prevented this from happening, but minimized jamming, reducing the coefficient of friction and significantly improving the performance of the machine. The gears were intended to be glued to the shaft after viewing other teams design, but it was clear that the epoxy could not support the torques that would be applied to it due to its poor strength under a shear stress. Set screws were then used. Although many other teams used inflexible couplings due to their simplicity, we later opted to use flexible couplings because they followed better engineering principles. This required small changes from the original design.

Our machine was able to utilize an unexpected quality to great effect, and this quality was discovered during the testing of our machine in the arena. The elasticity of the pulley belt created a spring like effect and allowed our machine to toss balls in a trajectory that most teams could not block or achieve. This quality was also very exciting and drew a lot of cheers from the crowd during the competition! However we were unable to defeat our first opponent despite the valiant efforts of our machine and its driver Travis in battle.

Here are some pictures of the completed machine:

Bill of Materials

Here is the link to the final bill of materials and expenditures for our machine:

http://spreadsheets.google.com/ccc?key=0AidQw1MTWOytdF9NM0FVUktadzhIWUJ5OC01clk1cWc&hl=en&invite=CNWyz7sC

Keval's Reflection

This class was both the most interesting and time consuming class I had this semester. The lessons I learned while participating in this program I believe were the most useful in terms of my development as both a team player and a professional. I aim to take these lessons not only into later design classes but also into internships and other team projects.

One key concept I learned about in this class was the techniques and concerns regarding the manufacturing of a design. I not only was exposed to the shop tools (mill, lathe, laser cutter, water jet), but I was also exposed to the issues an engineer must consider when developing a part. The concept of quantifying the quality of manufacturing (surface finish, flatness, geometric and scalar tolerances) were very interesting to me, and brought me to appreciate the amount of thought that must be put into the manufacturing of simple every day objects (particularly the quality).

This class heavily trained me in time management. Due to the amount of work that had to be put into the project, as well as the workload in my other classes, time became my most valuable (and most scarce) resource. Utilizing time and resources became critical in the execution of completing the project. One thing I learned very quickly is that the distribution of time between manufacturing and design was critical. Time was spent more efficiently when it was put into quality design work rather than put into engineering. This class demonstrated to me quite clearly that the initial investment in time for design is very rewarding in the future.

Teamwork was vital to the completion and success of the project. This class taught me a great deal in the value of teamwork in the completion of a project as well as the skills necessary to effectively communicate to each member of the team. Communication was clearly one of the most important skills needed in a positive team environment, and I believe all teams recognized this over the course of the class. One challenge that our team faced was the difficulty of meeting other members. Due to classes, extracurricular activities, homework, exams, and logistics it was difficult for the team to meet often for useful periods of time. Tasks had to be delegated between members in order to complete things on time. However this delegation was both uneven and inefficient, which led to delays in our schedule.

I believe my performance in this class could have been improved if I had a less demanding schedule. I had difficulty coping with my course load this semester and budgeting my time in order to ensure my success in all my classes. I have no regrets with the amount of effort I had put into this class. If anything, I have learned that I should have been less generous with the amount of time I allotted to the class. That way the time I would have spent would have been used much more efficiently.

There are two major concerns I had with this class that I felt should be addressed. First, I believe that the design process and team selection should be done earlier so that more time can be used by the teams to properly design their machines. I believe the development of the manufacturing design took the most time and required the greatest amount of effort. By giving teams this extra time, they may have the opportunity to properly design their machines and have them reviewed by the course instructors in proper detail. The other concern I had was the difficulty in interpreting the expectations for each assignment. It was difficult for me to prepare (and therefore determine how much time to invest) for assignments in this class. This issue I feel will be minimized as the course is refined over more years.

Travis' Reflection

ME 250 has been a great learning experience for me. It was my first dip into the world of design processes and machining. Most importantly, it was a great chance to learn how to work together with a few bright people to visualize and create a (hopefully) well-engineered product. Not only were the members of my group all learning about the design and manufacturing process together, but we were applying that knowledge in a near real-life manner. We learned the value of teamwork, as well as the importance of time management.
Of the lessons I have learned over the course of this class, I hold teamwork as the most important. Very rarely does a class allow for a kind of real-world teamwork. The third and final segment of this course was pure teamwork, and because of the intensity of the teamwork forced upon us, I feel I have greatly improved both in getting along with and understanding team members. I feel I have also improved my understanding of what must be expected of a team member, and how even the smallest of mistakes might be seen by those who are depending on good work. It works the other way, too. Even a small gesture of kindness toward your teammates goes a long way. If one could take the project home and finish that one thing that has been bugging the team, it might not be a lot of work, but you will get a lot of appreciation for doing it. Unfortunately, I also witnessed some poor teamwork (in other groups) and the effects that it can have on both the team members and the quality of the product. Overall, I have learned that I will usually have to work with others, and when I do, I will know how important good teamwork is.
Time management was critical on a big project like the one we had, especially because few of us knew exactly what to expect, as we were all learning. The deadline dictated many of the days we were forced to work, and many times we found it necessary to spend hours more than we had planned. Without planning, though, we would have been in heaps of trouble.
Of the design process and manufacturing, I learned a great deal. I hardly knew what a metal lathe was before I took the shop classes. Now I can boast that I not only designed a part to a real robot, but also cut it on a laser jet! I feel much more familiar with the methods of thinking required in the design process, and am somewhat comfortable with the important machines in the workshop.
This course benefited me greatly, but can still be improved in several ways. Most importantly, I felt that we were not given as clear a view of the project as could have been given. Many rules were made up as we went along, and in many cases we had to design things on only a half-knowledge of what would really be given us. A good example of this is that many people had ideas of a sort of vacuum machine. Until we were able to actually look at the arena and the kit contents, it seemed like it might have been a good idea. I personally don’t know how to make an effective vacuum tube out of simple parts, so I came up with simpler ideas, but that was just what they were; ideas. Partly, I understand that the first few weeks were designed to stimulate our imaginations and give us a chance to walk through the design process, but many of us wanted this walk to benefit the project we knew we would be faced with, and that simply wasn’t possible. Another point I might add: Our homework grades came back to us very slowly, and I must have turned in seven or eight assignments before I was given any idea how I was doing on them. I believe that it is important to hand back assignments quickly (and to give more constructive feedback; There were times when I looked at my answers and didn’t even know why that “3” grade was there instead of a … I don’t know, “4?”) in order to allow the students an earlier chance to get motivated. Most students probably thought they were doing fine. I wonder how many would have done better and tried harder had their assignments been given back in a timely fashion?
Yes, I did put in a lot of work throughout this course, but I do realize that I could have done better myself. For one, I could have made sure to get more sleep, so that when I came to class I could concentrate better. Life always seemed to prevent that this semester. For another, I sometimes found myself pressed for time and thus unable to put in as much of an effort as I would have liked on an assignment. I still did fine, but I could have done just that little bit better.

Video

First Week of December: Pics!

Top: Dan, filing the arm hole in our chassis to prevent the arm from binding.
Second: Our completed machine (!) being tested out on the arena.
Third: Arm pin plates + inner plates + the arm. We needed to add inner plates (seen here with hex bolts coming out of them) to keep the arm constrained to the PVC pin plates. It tended to slip off one side and bind.
Bottom: Rack and pinion assembly shown with all applicable gears/motors/couplings. This assembly also encounters more friction than we would have originally preferred, but it still operates fairly smoothly.

It Works!

So, folks, our machine was actually up and running in the arena today! This makes the effort of the past (crazy) week much more worthwhile. Most of this week was spent manufacturing the parts of our machine which hadn't been finished the week before--axle mounting brackets, axles, the chassis plate, and arm pin plates (which guide our machine's arm as it is driven up and down). We also mounted all of these manufactured parts to the chassis, mounted the motors, and completed the wiring today.

The manufacturing of our parts was fairly uneventful. The chassis was cut out of plywood with the laser cutter. This meant that it didn't require much post-cutting work, though determining proper hole placement in Solidworks was very time consuming. Our axle brackets are simple pieces of aluminum L-channel with holes milled into them, while the axles themselves are 1/4" shafts which have been turned down on the lathe to allow for e-ring clips and other hardware, like set-screws. We did run out of 1/4" aluminum shaft material, though, so Travis managed to pick up some 1/4" steel.

Coupling our motors to driven shafts was a little difficult, mostly owing to bracket size (axle brackets interfered with flexible couplings). Thankfully, Dan was able to take these brackets home and grind two of them down significantly, which fixed the problem. The motors are coupled to the shafts with flexible tubing, pinned through with short peices of steel welding rod--a handy trick we picked up from another team. The wiring of the motors also was fairly smooth once we'd gotten the hang of the soldering iron. We believe that we've managed to wire our machine so that the wiring won't be vulnerable to attack, but that remains to be seen.

The hardest part now will be to learn to drive the machine with the existing controls. We did get in some drive practice today once our wiring was complete. The driving was erratic, but we hope to improve with practice and perform well at next Thursday's competition!