In theory, I should have loved this class. It embodies everything that I want to do with the rest of my life. There is something amazing that happens when you take an idea and make it reality. There is a sense of pride you get from creating something with your own hands and watching it take form. Or that has been my experience.
This class wasn’t like that for me. I left everyday feeling frustrated with what had to be done and the time we had to finish it.I understand that there is certain amount of benefit that can be had from letting people figure things out on their own, but in a class like this, where the time is limited, a bit more structure would have been beneficial. It takes experience to realize what sort of ideas work and what ways of doing things are most efficient. Teams without that experience were at a disadvantage. If you’ve never been in a situation like this class before it is easy to write off some things during the design process. The way we wrote off the time that it would take use to drop our platform or the moment arm on the rack and pinion (Both of which came back to haunt us in the end). It would have been nice for those with the experience that we lacked to inform us of our misconceptions, to take us aside and say “look at this, will it actually work the way you expect it too?” . It is reasonable to expect us to do most things on our own but this is still only a 200 level class, and it should have been taken into consideration that not everyone knew exactly what they were doing.
Although this class it wasn’t my first experience with the design process it was my first chance to work in a machine shop setting, my first chance to work with CAD and the first time I’ve ever had to deal with motors and their limitations in when I thought about a design. I found working CAD to be very beneficial in visualize a design, and overall I enjoyed it more than I thought I would. If I could design in CAD for the rest of my life I would be happy, that program works the way that my brain thinks. Although I had experience with hand tools I had never worked in a machine shop setting before. I definitely learned a lot, but I know that I have only scratched the surface of knowledge in this area. There is definitely more that could have been done in this area before we were set loose to manufacture our own parts. The two lab periods we took to actually use the machines in small groups was more beneficial than the machine shop training. Doing hands on activities instead of simply feeding us the information makes the processes stick a lot better and would keep us from needing to ask simple questions later on.
If I had to take this class again, knowing what I do now, I would have done things a little differently. I don’t think that our strategy is bad, having the ability to score when the opponent locked the flipper is a valuable idea, but the design we chose poorly executed this strategy. Looking at the most successful teams most of them had multiple one module, one that controlled the flipper and one that worked on the top of the arena. Smaller robots were easier to maneuver and those that were best manufactured used pulleys and belts instead of Kevlar thread. However, despite our bot’s obvious flaws, I am proud of what we accomplished as a team. There were some times where we struggled and some times where we excelled but we all worked hard to make our robot functional in the end.
I had high expectations for this class. I thought it was going to be an experience that confirmed that I made the right choice in deciding to be a mechanical engineer. But I can’t say it did. Things seemed disorganized on a regular basis (especially for the motor lab) and the constant alteration to the rules throughout the class was a bit frustrating. With a bit more organization this class has the potential to be something incredible. But I regret to say that it is not there yet.
Coming into the ME250 class, I expected the class to be particularly challenging for me, because the Engineering 100 class I took previous semester was particularly challenging for me, and it also focused around an opened ended project involving a team. After going though the course my expectations turned out to be true, however the two courses were not as similar as I have expected them to be.
The ME 250 course seemed to be much more specific to me than the Engineering 100 I have taken during my freshman year, which I believe is good, as sometimes I tend to get lost in a very open- ended situation. I found the fact that the class is split into 10 Milestones very convenient, as it allowed me and my teammates to gauge our time and effort appropriately. The smaller details we have learned, for instance the FRDPARRC diagrams for our concepts and modules, as well as the Pugh charts also helped us save a lot of time during the design process. These tools, although they seem very common sense, had saved us a lot of time during the design process, a time when it is very easy to get lost in the amount of ideas.
The things we learned from the mechanical elements lectures helped us realize our design. Even though we had slight ideas about what kind of components our machines needed to be made of before these “elements” lectures, these lectures helped us finalize many of the grey areas about our machine. I liked the general timing for these lectures, as if they were later, these grey areas could have turned into large problems by the end of the course, which in combination with the manufacturing problems we had while assembling our machine would create a very unpleasant experience. The homework assignments and the labs helped me realize how and where we could possibly use such components as the springs, bushings, bearings and gears.
I have also learned that manufacturing is a much longer and harder job than it seems to be. Although one of my teammates and I have familiarized myself with how to use the mill, laser, and the drill press quite efficiently, we still asked a lot of questions to Bob Coury/ John Mears whenever it came to other machines in the shop. At the start of the manufacturing period we spent a day manufacturing one small part of our project (for instance an L-piece), paying close attention to how the surface is finished, and spendingmore time running around after Bob Coury or John in the machine shop. Eventually we started falling a bit behind schedule, and took up more and more hours in the shop. As we got more experience with the tools and started focusing more on the big picture than on the small details, our project started catching back up with the schedule. I believe, although the ME 250 gave us a good introduction on the tools in the machine shop, it will still take a lot of time for us to learn how to manufacture parts by ourselves.
We have also expected, and experienced, that the biggest problems in the project would come up at the very end, just as it is being put together. Although this did cause a period of initial depression in all of the team members, we were taught somewhat of a systematic approach on how to address the problems with our machine. The GSIs gave us tips on how to eliminate some of the problems we were having with the sweeping arm moving without completely remaking our machine, and just changing some small parts. We adopted this approach, and during consecutive assembly problems (the lack of torque/traction on our driving wheels, the slipping occurring in the planetary gearbox during operation) that we had it was much less painful for us to go though processes to develop solutions to our problems.
Although many things that we learned in the course about design and manufacturing might seem common sense and obvious to a person looking at the course form a third person perspective, I really believe it was the first hand experience that would make you to appreciate the things learned in the course. Some of the things in the lectures, like the hooks law, the cantilever beam, and Ashby’s method I was familiar with previously, while some of the things, like the capstan effect, the engineering drawings and tolerances were new things to me. However, during this class the most important thing that I have learned is how to combine our knowledge about all of those and many other details into a “do-it-yourself” project was.
Teamwork was another aspect that was not very easy for me. I am a fairly poor English speaker, so I have a hard time expressing my ideas to others, who I realized would not always be willing to listen to me trying to express them for long periods of time. During this class, I have talked to several other people in other teams, and they told me they had similar problems in communication with their teammates. Another important aspect about teamwork, which I have observed (and seemed to dislike a bit), is that it happens much slower than individual work. Every person (including myself) had a different schedule and took a certain time to understand what was going on, and expressed a larger affinity towards their own ideas rather to the ideas of someone else on the team. This was especially evident in the beginning of the course, and became less and less so by the end of the course, when we started getting used to each other. I tailored myself to the team a bit, however I still believe there is much more room for improvement.
As for the course itself, I felt that it was a bit too end-heavy. The start of the course is very light, while the load gets progressively heavier though out the year. I understand that it takes a lot of time to get the students into the mood of the course, and to form the teams, however I do believe that the design/ and the early portion of the course can be truncated to 2-3 weeks, with much more time left for the design and manufacturing of the actual team project. I felt absolutely horrible about having to miss a certain class two times in a row in order to complete the project, and while this is partially my fault, I believe the course can accommodate for these things not to happen again.
I also believe the shop training can be much improved by moving it up closer to the manufacturing part of the course. Although 250 is not the only class working in there and the shop training has a potential to interfere with other manufacturing courses, I believe that there could be some time spared in the middle of the semester to teach us how to use the machines.
Finally, since I have experienced the course, I can realize that my performance in the course can be improved. I think that the first thing that I would like to change is my attitude when approaching “team project” courses. Since I already had a similar (to a degree) course previously I initially expected that the course would be rather painful for me. Initially I tired working very hard, looking after every little detail, however I became more and more focused on the big picture by the end of the course, sometimes neglecting small details, and having my teammates remind me about where to go and what to do (sometimes from lack of attention). I believe if I adopted a more uniform working habit (although I doubt that would be an easy thing to do), my performance would be improved. Another thing that I might want to improve upon is the passive approach I took during some of the decision making concerning the project (for instance picking the team strategy). Although it is an important idea to preserve the team, to prevent arguments from destroying it, it is sometimes very critical to stand up to your teammate’s ideas. I think if I (as well as some of my other teammates) would have stepped up for a team strategy/concept different to the one that we proposed (that was a less complicated concept) instead of taking a passive approach backing out of an argument we might have had less of a hard time accomplishing our final machine then we did, and focus more on the fine details that make up our machine. Although back at the time it was a very hard tradeoff to predict, it would be very good for me to think ahead next time instead of taking the passive approach.
Overall, this class was a very good introduction for me to manufacturing, and design processes, as well as another practice of developing teamwork skills. I think the class could be improved a bit form what it is/was this semester, but the main discomfort probably came from my lack of experience in manufacturing, teamwork, projects, and open ended problem solving. This was the job of this class for me, to provide me with these experiences.
Our machine has the following major modules: car frame, top plate, middle platform with both sweeping arm and scoop attached to it and the bottom plate to attach wheels.
The top plate has a planetary gear box motor on it and forms a pulley system to move the middle platform up and down sliding against the car frame and wood pieces. The platform has four extrudes instead of four wheel since this will be simpler. There are four strings attached to four corners of the platform by eye hooks. Our most critical module(MCM) is the sweeping arm which slide inside of the slot on the platform with the restriction of the nuts.It has a motor on the top. We had issue with the rack and pinion system which generated an undesired moment. So we changed it by using two strings wiring in the opposite direction on the aluminum shaft. in this way, the sweeping arm can slide horizontally, both open and close the scoop. We also attached two acrylic plates on the end of the platform to prevent it from bending. The sweeping arm is adjustable for its length due to vertical slot.Bob helped us weld the scoop. We extended the volume of the scoop so it can fit more balls.
About the car frame, there are four angle stock to support edges and there are a total of four pieces of wood which form sliding slots to allow the middle platform move up and down. we have a double gear box motor attached to the bottom plate and the motor shafts were pressed fit in the front wheel shafts. We used a single piece of aluminum to attach the back wheel.
When the machine is powered, we lower the middle platform and reach the balls. Then close the scoop and lift the whole platform up and drive to the other side of the table to dump the balls into the funnel. What we actually did is to lower the sweeping arm inside of the slot and push the balls towards the flipper to score. This worked pretty well in the seeding round. We designed it as multi-functional.
Here are some pictures
ME250 IS AMAZING----It's a course that enables you to have some hands-on experience, ability to turn ideas into reality and it's hella fun! But don't get excited. This course will consume most of your time, starting from the design review to the end of the semester. Let's talk about the down side first.
I'm going to be brutally honest in this post. This course was very chill at first(you know, some drawings and sketches and random ideas how one's team is going to completely dominate the competition) but then it got exponentially difficult. There were many occasions in which our team worked and stayed up late; there were times when we have to get up at 8 A.M. to work in the shop. Working five hours straight on the project was fairly typical and skipping other ME classes(*cough cough* thermo) just to fix a small part to meet the MS deadlines.
I really wished we had formed our teams earlier instead of conjuring up ideas that we tend to abandon when it comes to thinking as a team. What i'm trying to say is that one person can have multiple ideas, but in the end, there can only be one. So it might have been more beneficial if we get together earlier and decide as a group that this is the strategy we are going to choose.
Unfortunately, however, we picked quite possibly the worst strategy out of the three. We decide to get balls from the slot and drive over to the other side! We had our reasons for such strategy and finally decided go with that idea. What we fail to foresee is that driving the vehicle can be a pain, unwinding the string can take forever, and having a 2 ft tall machine is another pain! Although we were able to score due to our multiple functional machine, so it was a trade-off.
Nevertheless, there was no turning back. It was half way into the semester, we had to carry it through.
As we finish manufacturing our parts, we started assembling things. This is where the nightmare of not envisioning the perfect slotbot comes in to haunt us. Our rack and pinion created an undesired moment that causes our arm to twist. Shaft for the wheel is too thin to be press fitted because we had to accommodate for the L pieces. Double gearbox was in the wrong gear ratio and thus our vehicle was not able to make over the surface bump. A thin piece of acryllic platform that literally bends due to the weight of the scoop and arm. And most troublesome of all, STRINGS! These Kevlar yarns are a pain! All these problems arise about a week(SEVEN DAYS) before the competition. We thought we were so screwed.
What separates a team of engineers from other people is the ability to solve practical problems. Your sweeper arm cannot move, so come up with a solution, and make it move. Your vehicle can't go over bumps, find a way to increase torque or friction. It was a time filled with frustration because there could be no definite answer to a problem. Despite in times of desparation and struggle, our team managed to tackle every single problem. Some attempts failed; others pathetic(Kevlar comes to mind), but those failures lead to success! We willed it through at the end. We were so proud when last minute ideas work. We learned to think under pressure and critique each other's ideas. This is a time when we(at least I did) felt pain and joy at the same time.
We find ourselves not having a life and basically living in the machine shop two weeks before the competition because we were so pressed on time. How does seven hours straight for 5~7 days sound? Mill/Lathe reserved almost everyday for 2 weeks? Having ME250 group meetings on Friday nights on multiple occasions?! IT WAS RIDICULOUS. Some teammates ended up skipping ME211, 235, and other jobs just to get things done. I ate dinner at 12:00AM once, literally, and my teammates probably have similar experiences.
Now that was pretty bad. There were good times too however. Learning how to CAD, and make engineering drawings will definitely help me in the future. Milling a piece of aluminum with a teammate and joke about everything to kill time was pretty fun! Not manufacturing correctly and provoking Bob Coury's anger was an amazing experience too! Having an awesome team that are willing to skip other important things to do ME250 helps too. Seeing that our machine was able to move pretty much paid off all the hard work even though we didn't make it too far on the arena. I'm so relieved and happy to have these teammates especially after last year's teamwork experiences.
This class is difficult(hardest class so far, I doubt it'll be topped in a while), but we all liked it. Seeing the pieces that we manufactured come together can be greatly rewarding. I hope all the other design classes(350,450 etc) will be as intense as this class, which fosters a friendly competition among the class. That was somewhat a masochistic statement, but I mean it. Working on projects is so much fun. I declared ME earlier this semester, and after taking this difficult class, it confirms my feeling that I made the right choice. =)
This is the most challenging course I have ever taken, including MSs, HWs and machines. However, after this first design course, I found what I really like to do. Being a mechanical engineer is so cool since you are making things into reality.
I missed those days in the machine shop, especially the week after thanksgiving. We found out a lot problems in our design and the rack and pinion didn’t even work. By trouble shooting, we changed our design for the most critical module. Though we didn’t use it either in the seeding round or the competition, it still works as what we want. A lesson I learnt is that never use strings again in any future designs. That is the real trouble maker.
Our team is the only one tried to lift the balls from the slot and grab it to the other side among the 28 teams. However, we also made the robot multi-functional as what we did in the competition. We tried to push the balls inside the slot as well but it was a pity that both teams could not get a single ball into the bin and we didn’t win that round. We did scored some ping-pong balls during the seeding round which I didn’t expect. I saw how other teams did in the competition and some of them are really amazing.
I have never been to machine shop before but during the 2 months, I learnt how to use lathe, drill, tap, band saw, hex saw, laserjet , waterjet and so on (I need to learn millJ) and I am really proud of myself and my team. We met at least twice every week and sometimes stayed late. It is really challenging to keep a balance between team work and individual life. However, it will be much better if you know what you are going to do and discuss during the meeting. In this way, the meeting will be more productive and efficient. Personally, I feel this course working load is much more than 4 credits. During the last two weeks, because of the deadlines of the project, I skipped many other classes and is suffering now since I have to catch them back. I was also lack of time commitment for my UROP project and obviously, my sponsor was not happy. Well, it is really hard to balance between all these things. At first, I was thinking about how to make things best and perfect, and near the end, I was struggling with how to have all my stuff done as soon as possible to meet due dates. It is just nearly impossible to keep all courses in the same pace and I have to abandon some of those.
One interesting thing is that I love You Tube due to this course (I could never use that before). There are lot tutorials for solidwork. I learnt how to make a nut and it worked pretty well. When you really want to make something, there is always a way to do it. Communication is really important. We are always getting confused by other's ideas and we had some difficulties to explain our thoughts to others as well. This is really interesting and I feel my English improved a lot. Pictures really help us to explain what we want to say.
During the last week, I changed my laptop screen paper into “cheer up” since it was just really bad and now nearly all things are over. I will miss my teammates and all staffs since it is really an unforgettable semester. As an international student, I tried my best to remember the names of every tool and all the procedures about how to run machines. Even though I have studied in Canada for one year, the first several weeks were still like nightmares to me but now the hard time passed, I am much more comfortable with the course content. Thanks all people who answered my questions (some of them are ridiculous though), especially Sei Jin, I always threw him random emails and can always get the answers back on time.
If I could take the course again (though I never want to do that), I will still devote as much effort as I can. About the machine, everyone wants to win. If I had a chance to do it again, maybe I will pick up another strategy and think more thoroughly but I really like our idea which is really special. Also, as what I mentioned before, I will never use strings again though they did a great job in our machine. Also, I will still ask questions if I don’t understand. I feel there is nothing I regretted about this course and all the hard work paid off.
My suggestion to the course is: please give us more time to machine and practice! We are not procrastinating but this project does need more time. To be honest, I really want to see people score which means their effort paid off, at least. It is really sad that either in the seeding round or competition, the machines barely score. This is why I love last year’s project much better since it was more competitive. Maybe it is harder this year, I don’t know. We tried, but it will be better if we can see some results.
Well, almost the end! To reiterate: Thanks my team, we are amazing and thanks Sei Jin, much appreciated your help and many other thanks as well.
Attached are the cute wall papers to cheer you up during the finals.
The winter break is coming, have a nice one!
(Sorry about the poor grammar)
---Jingjie Hu
Tuesday, December 7, 2010
Sunday, December 5, 2010
This week we spent our lives in the shop manufacturing and wrapping up our machine. We ran into many problems as we assembled though, but we were able to come up with clever solutions that make our machine possible.
As you can see, the machine has a platform that moves up and down and it has an arm that sweeps the ball into the scoop.
We also have a motor on the platform, one on the top frame, and a double gearbox on the lower frame to drive our vehicle.
