Team 9 - Poison Darts

 Design and Manufacturing:
This class has been an outstanding refresher for the material that I already knew, and a great supplement for the material that I did not know. I only understood basic machining principals, the ideas behind alignment of shafts and supports, couplings, fabrication and assembly strategy. First and foremost, I did not have any knowledge of the solidworks program. My section leader Mark Gordon is an outstanding GSI who showed great competence and patience while handing us the foundation and basic principals of the program as beginners. Our team spent endless hours drafting our slot-bot, and found that the prints we generated allowed us to produce the project that we intended on having, nearly to perfection. The program aided us with critical dimensioning for machining that we wouldn’t have been able to produce by hand, under the scheduling guidelines. The only errors we struggled with were those in our engineering.
Furthermore, I learned how several types of levers, gears and springs were designed, along with a diverse explanation on dynamic inputs and output responses and applications for special situations. Although our team didn’t use many of the different mechanical concepts that we were shown, we did think about them. The lectures helped open up some of the creative options that were available and I noticed many of the applications shown in class being used on other teams’ slot-bots. I learned almost as much from looking at others’ slot-bots, as I did ours.

 Teamwork and Time Management:
We had a hard time pulling things together at some points due to our class schedule. Each of us had a full schedule and it made it tough to plan things outside of normal class meeting times. Typically when we did meet, say, on Friday nights for instance, we would spend 6-8 hours together trying to cram in as much engineering as possible because we didn’t know when we were going to be able to meet again. We were able to stay on task, and remain focused on the goal of the project. Our wasted time was minimal. I feel that some of the machining fell a little heavy on me, but the others tried to make up for it the best that they could, and often asked if there was any way they could help. Just the thought of them asking, made up for the fact that there wasn’t much else they could do. Because I had more experience in machining, things just worked out that way due to the time constraints. As a whole, I feel the weight of the project was distributed as evenly as it was ever going to get. Each of us showed the strengths in the areas that we were strong in, and did the best with what little time we had. Communication flowed great, and I think each of us adapted to our workloads well.

 Class critique:

How the class can be improved:
Many of the classmates, including myself, felt that there was far too much emphasis on the creativity portion early in the term. On a whole, myself (and others) felt that the creativity was a good thing, but there was enough of a diverse spectrum within Mike Umbriac’s lectures on levers gears and springs etc. to make the significant contribution to open minded development of the project. He did a great job in expanding our minds to new ways of thinking and different ways to look at things. However, once his lectures rolled over into engineering and machine time, I felt like we were constantly behind. Perhaps a good switch for early creativity emphasis might be to schedule the motor lab early in the term. This would possibly help to bring scope of motors’ potential into the engineering and design areas. Due to the fact that the motor lab occurred so late in the term, I heard some students mention that their engineering was completed before they had the chance to see what the motors could do.
I was definitely surprised at how slowly the car moved with the double gearbox motors. If there were one improvement I could have made, it would have been to make those two motors stronger, or upgrade to a more powerful gearbox/motor setup all together. I feel that we would have won the competition had we not suffered in the tabletop play due to motor weakness. It was a bit unfortunate after 16 weeks to see the car unable to negotiate the white strips of delrin, with our mass. We were asked to calculate gear ratio based on feet/second and as it turned out, the small motors were too loaded to achieve our goal with proper ratios. We over-estimated their potential.
I feel the bike lab was not needed. We covered many of the principals of this lab in class. Mike walked us through some calculations in preparation for it. Perhaps some practice of these calculations would work out well for a homework assignment instead.
I think there needs to be much more emphasis on machining process and tact. Mike’s blueprint section was outstanding and very helpful not only to this project but to our future. But beyond that, I noticed there was very little classroom time spent on machine setup and process. There was no way for Bob Coury to teach 100+ students proper and safe tact to machine parts. He was so busy, people sometimes didn’t have time to ask him what to do, and they tried doing it themselves, sometimes doing things wrong and getting caught. Although he offered his help as much as he felt he had time to, many of us saw him lose patience on several occasions and simply threaten to throw students out of the shop for what he considered improper method without a first warning, or even first address. In retrospect, I feel he was simply overwhelmed with the responsibility of trying to make sure students do things correctly and this burden (due to the number of students) pushed him to his limits of reasoning. If there were classroom time that announced basic patterns of logic (i.e. how to correctly secure parts in the vice, or how to machine in stages such as the machining process asked for on the exam) then Bob would have some background on the student to ask them about; Bob could ask, “How were you shown in class, does your way seem reasonable according to what you were taught?” Without this foundation, he was left to teach proper or safe tact himself, to a seemingly endless number of eager-to-learn students. In my opinion, it is far too much for one man to handle in that short time frame. I might have lost patience too had I been in his shoes.

How I could have improved
I took too many classes this term. I feel that the content of this course is strong enough that students who have more than 12-14 credits (as I have 16 credits) should be aware of the time commitment that is needed to be thorough in designing engineering, and manufacturing processes. Although I never lost focus on the project, I found it difficult to maintain a schedule and still remain in good standing in other classes. My grades have suffered in one class in particular due to the demand of ME250. I am now taking huge strides to catch back up.
There are many other improvements that I could have made. Each point that I have lost on assignments is an improvement that I feel responsible to make upon myself. (If I explained all of my shortcomings, this reflection would go on forever!) I am nowhere even close to perfect, and have found this class to be a tremendous learning experience. The extreme detail that was covered for us is untouchable. Professor Hart, you have an OUTSTANDING foundation in this material, and are definitely the right person for this job. I thank you greatly for sharing your knowledge and experience and all that your team has showed and taught me. I found this class to be very valuable in my education as a Mechanical Engineer. Mark Gordon is an outstanding GSI. I thank him for his extra effort in this class as well. Mike Umbriac and Toby are also outstanding members of your team; I appreciate all that you guys have done for this program.

After a rush of machining and assembly, we got our MCM up and running for MS8. Our car drives and turns well and the sweepers proved capable of collecting and holding balls. Some changes to the gearing and more traction on the drive wheels are needed to optimize performance, but even as it is right now I think it's safe to say our triumph is inevitable. Unfortunately, I didn't take any pictures until after we'd passed on the control system and begun modifications.

Steve adjusting one of our gearboxes

Our MCM with sweeper motor removed, but showing off the sweepers and drivetrain.

Final CAD model of our MCM with a secondary module attached

All of the engineering for our other modules (which focus on slot-play) is also done, and next week will be a flurry of activity as we work to machine and assemble those modules.