Individual Reflection - Ryan Matheny

ME 250 was a very entertaining and informative course that had very direct “real-world” applications.  The lectures were well structured and insightful, and really helped to teach the basics of mechanical design.  I believe the class succeeded in providing a challenging design scenario while also being a great course for students new to design and manufacturing.

I believe I learned the most about the manufacturing process through ME 250.  Prior to the course, my only experience with the machining equipment in the ME Shop was with the drill press, band saw, and smaller, hand-held tools.  I learned about the mill, lathe, and other machines extremely useful in the machining process.  One subject that I thought I had known enough about prior to ME 250 was precision measurement and tolerances, but quickly learned that there was much more to know.  I was very surprised to realize just how tough it is to make parts to very precise dimensions, and even how much variance there are in many stock dimensions.

The design process was a topic that I had already been introduced to in my section of Engineering 100, but I still was taught much about it through ME 250.  I quickly realized that as I made design concepts for our machine each concept was either unrealistically planned, or was missing components such as L-brackets that are needed to realistically assemble the machine.  Lectures such as the one on design heuristics really helped to teach me how to logistically construct a design prototype.  Furthermore, after completing this project it is apparent to me how crucial good teamwork is.  Each group needs both active participation from all of its members and solid communication.

I believe the course could be most improved by improving the schedule and timing of events.  It seems like between my experience and that of my friends teams, most people agree that there just didn't seem like there was enough time at the end of the semester to finish all that was required.  I understand that this could have been prevented by teams planning ahead better, but I found this quite hard to do during my first legitimate design and manufacturing project.  I tremendously underestimated the amount of time it would take to correctly machine every part and assemble the finished product.  I believe this could be helped by advancing the milestone requirements to be due a little bit earlier in the semester, so that students who don't have experience manufacturing are forced to begin manufacturing earlier.

I could have improved my performance in this course by planning out our design more thoroughly, using professors and GSIs as an aid more frequently, and allowing more time for assembling and testing our machine. There were many specifics that were overlooked as we were designing the CAD model of our machine, such as holes needed in multiple components for L-brackets.  Had we planned out exactly how to assemble everything prior to "finalizing" our model, we would have had a much easier time manufacturing the components needed for the machine.  I also believe that I failed to ask enough questions to professors and GSIs about my team's design, which could have helped prevent many of the problems we didn't see. 

Nathan Janes Individual Reflection

Being in ME 250 this semester was definitely an interesting experience for me. As a person who had never really designed or manufactured anything before, to be asked to completely design and create a machine from the ground up that was capable of a certain task was completely new to me. I found that the design process that we were led through was very unique and unlike anything I expected. Before this class I had never heard of a Gantt Chart or Pugh Chart and I found that they were good tools for keeping a schedule for a project and picking between strategies (or anything for that matter). I felt like as far as the design process, we were led through the steps to designing a machine very well and in a way that made logical sense. One thing I particularly liked about the design process was the use of SolidWorks as a tool to visualize and create the machine and it's parts. Additionally, the training given in the form of the labs was sufficient enough to give a student the basics needed to run the program, and then allowed them to fully expand their knowledge by trying new things within the program. As a person who had had previous contact with SolidWorks, but was by no means a master, I felt that the labs did a great job teaching the important aspects of SolidWorks as well as those tools that would be directly relative to the designing of the machine.
The manufacturing process in this class was also completely new to me. As a person who had never previously used any tools more complex than hacksaws and handdrills, learning to use a mill and lathe was an awesome experience. I found that it was very interesting to be taught to use these machines and then being forced to think through how to make a specific part based on combinations of these processes and more available in the machine shop. One thing I can not stress enough relating to the manufacturing of the parts for the machine is the help that Bob and Mark can offer to students. They both are insanely knowledgeable when it comes to anything in their shop and they extremely nice and helpful to students asking for advice. They are also the perfect combination of hard-asses when it comes to safety and shop protocol but they are more than willing to help students with anything that they are unsure of.
Being on a team during this project was a different experience all in itself. I hadn't worked in groups of people very often in the past, especially not on a project of this magnitude, and with that came a lot of new challenges. This project required an immense amount of coordination among the different members of the team, and that definitely tested the limit of my organization skills and by ability to keep everything on track. As the team captain it fell to me to keep everything going and in the right direction, and this was a semi-new experience for me so it was one that I was constantly learning things about myself and what it means to be a leader of a team.
Time management was critical in this course. Our team seemed to be a half-step behind where we wanted to be for a good chunk of the manufacturing time, but we were able to put it all together at the very last moment because we were all able to put in a bunch of hard work. One thing I would suggest for teams in the future is to start things EARLY; be they MS, HW, or any other assignments. If you leave these until the last minute, you will either get caught up in another class and get in trouble with the ME 250 assignment of you will not be able to complete the assignment as well as you should due to the time constraints.
I feel that the course could be improved by getting the students the students in the machine shop earlier in the semester and by forcing them to so both the mill AND lathe exercises. I only did the lathe exercise, and because of this I tried to do as little work with the mill as possible (although I did end up making multiple parts on the mill). Many students, including myself, have never worked with any tools more advanced than a hacksaw or handdrill, so to all of a sudden be thrust into using a lathe and a mill is a big step. But the only way for the students to get comfortable with these machines is to get them as much practice as possible, and as soon as possible.
I could have improved my performance in this course simply by starting assignments earlier. This course has so many assignments, MS's, HW's, and the like that it is easy to lose track of them and somehow fall behind. It is so important to stay organized and to stay ahead of schedule, because falling behind can prove disastrous. Overall though, for as tough, stressful, and hectic as this course was, I did learn quite a bit from it and the end result was a cool machine.

Final Bill of Materials

Here is the link to the Final Bill of Materials for Team RANA #39
https://docs.google.com/a/umich.edu/spreadsheet/ccc?key=0AnxBLjjxwlLRdFVkQUF4ZkNLWkwzMjJDOUZud2dRdkE#gid=0

Adam Brege Individual Reflection

Thus far in my mechanical engineering career here and the University of Michigan, I found ME250 to be the one in which I learned the most from taking, beyond just the topics which the course covered.  In my personal opinion, I find it much easier to learn when you are working towards some physical goal, in this case our machine than I do in “problem” based courses or those with your weekly homework assignment and three exams or what have you.  By having a goal to work towards, you get to see the forces and work and the issues that can be created by lack of planning or incorrect work when calculating forces for example.  When it comes to the actual course material, mainly design and manufacturing, I came into this course pretty much completely clueless.  I had never manufactured anything of any degree of complexity.  The first time I had done anything even remotely similar was in my Eng 100 class my freshman year, but that hardly compares to this or what will come in ME350 or ME450.  What I learned was that while the design and manufacturing of a product can be extremely stressful and at times difficult, but the reward you get from seeing the finished product is well worth it.  Along the same lines, the evolution of your idea into a working physical object is extremely satisfying as well.  I also found working in the machine shop to be a fantastic learning environment, by working on mostly the mill in my case, I was able to see how the shape of a part would affect the forces acting on our machine in both positive and negative ways and how a small error when machining can lead to a much larger issue when it comes time to assemble.   Another big part of the class was teamwork and time management and my group was one of the best I've had the pleasure to work with.  As far as teamwork is concerned, I feel my group was all equally committed to the task at hand and for this reason we were able to succeed.  On the other hand, our time management, while fairly good did result in us having to make some last minute adjustments that probably could have been avoided had we began assembling our machine earlier.  For example we were forced to cut the arm on our machine smaller so we could no longer reach the red balls on the top of the arena because the weight of the arm was more than the motor was able to handle at its original length.  Had we managed our time a little better, we may have seen this issue earlier and been able to come up with a more elegant solution to the problem that wouldn't have completely changed our strategy.  In the end, encountering problems when manufacturing something is to be expect and can be very enlightening, but depending on one’s time management these problems can either be a chance to improve and expand on your idea or an issue that must be dealt with in the easiest and most efficient way possible.

                Overall, I felt the class ran very smoothly, one area I experienced that could be improved upon is the communication between GSI’s and the course instructors and the machine shop.  We ran into the issue where we had planned and told our GSI about our plan on assembling part of our machine, but when we went to do it, we discovered this was not possible even though we had been lead to believe it was.  While I do not place the blame on our GSI in any way, as it mainly our responsibility to make sure our design is good, I still feel more communication would be good.  Also the machine shop was extremely crowded and there was a lack of machines for the number of groups that needed to get on them especially towards the end of the class.  Finally, I felt the exam did not represent the work we had done so far in the class well at all and the exam review did little to help with preparing us for the type of problems that would be on the exam.  I could have improved my performance  in the class by taking better notes and not relying on the lecture slides on line as much as I did and asking for help earlier in the machine shop  than I did.  I felt like I was clueless the first day I spent in the machine shop and because of self pride mostly I guess I wasted time being too nervous and stubborn to ask for the help I needed.  However, I did change my ways quickly and enjoyed and learned much in the rest of the time I spent working in the shop.

Team RANA Final Blog Post

At the start of the semester, our team decided that we wanted to create a machine that was capable of efficiently collecting the red balls  from the upper ledge of the arena without having to travel up the obstacle-filled (golf tees) incline to do so. Thus, we quickly decided to manufacture a machine with a rotating arm that could "rake" the balls down from the incline so that we could collect them and deposit them into our own goal. The benefit of this strategy was that we wouldn't actually have to collect many balls to earn a large number of points, which would make our team difficult to defend against.
Initially, we made our machine as bulky as possible, with its largest components barely fitting inside the 12"x18"x24" guidelines. After making a solid model of our concept, however, we realized that maneuvering our machine around the tower would prove very difficult (and it would be impossible to move behind the tower if we wanted). Finalizing our then-concept of the machine on Solidworks and checking the mass properties, we also realized that the dimensions we had set would make our machine far too heavy for the motors that we were being provided with, so we spent some time during the following week making our machine more compact and using different materials (e.g. acrylic) where possible to make the machine lighter.
Our machine had two independently-driven wheels in the back, with two ball casters (one from our own kit, and one obtained from trading with another team) in the front. This allowed us to maneuver the machine easily with a very small turning radius. Our most critical module was our arm/trap door mechanism. We had a single planetary motor that controlled the angular motion of both the arm and the trap door. The idea was that, as we lowered the arm to rake in balls, we wanted the trap door to be open so that the balls could be collected in the machine "holding reservoir" (area behind the trap door within the main body of the machine); then, we wanted to somehow close the trap door so that we could move the machine around without losing any balls that we had collected (we saw that this was a major problem with previous years' machines and was something we wanted to avoid). The way we decided to do this was to introduce a series of four gears, one of which would be driven by the motor and which would drive the other gears to move the arm and trap door. In our final setup (as is apparent from the pictures), lowering our arm automatically raised the trap door, and raising the arm lowered the trap door.
When we finally manufactured and assembled our machine, we realized that we had to revise our strategy since the planetary motor could not drive our long arm. Thus, we made the decision to shorten the arm and go after the black balls on the incline. Once we shortened the arm, the planetary motor was easily able to control the motion of our arm, and our most critical module worked beautifully.

Finalized Machine, showing arm and trap door in the starting position

Close-up of MCM, showing arm and trap door in starting position

Amir Maghsoodi's Final Reflection

As a non-engineering student, I took this course solely because I was interested in becoming more familiar with the overall process of design and manufacturing; in this regards, the class has been a great success for me. I appreciate the confluence of theory and application that the course provides, and being able to end the semester with a functioning remote-controlled machine is a very gratifying, and cool, experience!

Design and Manufacturing:
I very much enjoyed the two aspects of ME250: design and manufacturing. I noticed that though these two processes are distinct from one another, they are also very much interwoven and interdependent. The instructors, I believe, did a good job of providing this understanding by the way that the lectures/labs were organized.
I learned the difference between effective and ineffective approaches to design, and I value the lesson of approaching design very broadly at first, then narrowing in on the specifics (strategy -> concept -> module -> parts...).
In addition to this approach to design, I also learned the importance of keeping the manufacturing aspect in mind when designing a machine. Our team did have to make some adjustments to our model because we did not at first take into full account the limitations of our kit materials, etc. In a future project, I would be more mindful of the interconnection of the two processes of design and manufacturing.
My favorite part of the course, and a major reason I had for taking the course in the first place, was becoming familiar with modeling things on Solidworks. The software is a very powerful tool, and being able to design an entire machine and create drawings of the parts with Solidworks was definitely one of the coolest things about this course in my mind.
Regarding manufacturing, I learned a great deal. I had never been trained in a machine shop before, so using the lathe, mill, drill press, laser cutter, band saw, etc., were all mostly new concepts to me. I used the mill more than any other tool in the machine shop, and so I think I now have a fairly comfortable grasp on how to use a mill in the future for manufacturing parts. In addition to these tools, I now have a deep appreciation for precision measuring tools and good practices of precision measurement-taking. The idea of tolerances is still not too clear in my mind (i.e. choosing a tolerance considering the application of the part..), but taking precise measurements is something that I both enjoyed and found important for our manufacturing and (especially) assembly phases of the project.
Teamwork and Time Management:
At a school such as ours, I find that I'm surrounded by many smart and driven individuals, and this was certainly the case in our group. Without effective teamwork, such a project as the one in ME250 would be impossible to complete in a single semester. I learned that when working in a team, it is important to voice one's ideas and sometimes even do so strongly and with dedication, but I also learned that it is highly counterproductive to become attached to your own ideas. In our group, I don't think we had the problem of people taking a rejection of their ideas personally. I think that we could have all expressed more differing ideas, which would have led to more innovation and creative/better design, but given that it was our first time doing such a project, our discussions and planning sessions were very interesting and fruitful.
Time management was the biggest issue, and we quickly realized that we couldn't all meet as a complete group every time. Especially when it came to manufacturing our parts, I think that the ratio of number of available tools in the shop to the number of students wanting to use those tools was extremely low, and this caused much unnecessary (though maybe unavoidable, since they are **expensive tools) delay in our scheduled plans.
Improvements:
I think that the course can be improved by increasing the speed with which the class hits the ground running at the beginning of the semester, and getting students into the shop earlier. Lectures were fairly interesting, though sometimes it was difficult to pay attention; I think that the videos and media play a huge role in sparking interest, and more integration of multimedia elements in lecture would improve the course greatly. I think also that the Mill/Lathe exercises were a waste of time. None of the people in our team got much out of those exercises, and we forgot everything by the time we actually started manufacturing.
I think that the final was very difficult, and the theory not emphasized enough in the lecture materials. I attended the big review session for the exam, and the GSI made it sound like it would be a fairly simple and straightforward exam (NOT the case), so I think it's important that the instructors provide some more guidance to the GSIs as far as the information that they are conveying to the students.


I could have improved my performance in the course by attending more office hours to clarify parts of the course that I didn't understand. I started to communicate more with Emily about questions/ideas I had towards the end of the semester, but I think I would have benefited more by doing that more consistently throughout the entire semester.
Amir

Team Video

http://www.youtube.com/watch?v=l7k8mKuQ_0k

MCM Finalized

Having finished the MCM, we are very happy with the end product. Below you can see some pictures of our finished assembly and compare them to 3D Solidworks images.

Final Assembly

Solidworks Model of Team RANA Machine (View 1)

Solidworks Model of Team RANA Machine (View 2)

Some parts of our machine ended up changing from the last post to this one, but none that were part of the MCM; rather, they were part of the main body and support structures.

Work on Arm/Trap Door Mechanism: Arm Axle and Trap Door

Here we can see Ryan working on the arm axle and Nate working on the trap door.
Ryan uses the measuring caliper to correctly dimension the axle and uses the lathe to turn down the diameter of the steel axle that we bought from McMaster

This is what we want the end product to be for the axle:

We also need to tap a hole to be able to screw the actual arm into the axle. Adam will use the mill to drill/tap the hole in the axle.

Nate is seen here working on feeding the laser cutter the correct dimensions to cut our trap door out of the stock .25" acryllic plate.

The purpose of the trap door is to hold the balls in when the machine is in motion. As the arm is lowered, the door is pushed outwards by the gear mechanism, opening the entrance so balls can enter the holding area. Once we raise the arm to move the machine, the trap door lowers and closes, trapping the balls in the holding area until we can deposit them in our goal.

Orthogonal View of Solidworks Model of Trap Door

MCM Intro: Trap Door, Arm Axle

Our most critical module is our raking arm/trap door mechanism. The components that comprise the entire feature are (including expected costs):

Part	Cost of entire stock	Fraction Used	Cost of part
Arm	4.06	0.92	$3.72
Trap Door	12.07	0.05	$0.58
Planetary Gearbox	14.25	1.00	$14.25
Gears	5.37	1.00	$5.37
Axle for trap door	2.90	0.75	$2.18
Axle for arm	2.90	0.75	$2.18
Extra axle for gear	2.90	0.25	$0.73
Rigid Coupling	0.00	0.00	$0.00
Arm Lip	13.82	0.03	$0.44
Total			$29.44

Team Schedule

Schedule for the next 7 weeks: http://goo.gl/p8Pfe

Introduction to RANA

Strategy
Our strategy is focused around collecting the red balls on the upper ledge of the arena, and also collecting the yellow balls closest to our starting zone at the beginning and end of our execution. We selected this strategy because it has a high potential for scoring, as its calculated expected score was the highest. This strategy is also very simple and should be easy to implement.  The strategy does not require a large amount of moving around the arena, as it is very centralized and is expected to make good use of the 90 seconds that are available.
Our machine will have two independently driven back wheels, with two caster balls on the front for stability (red). The arm and trap door at the front of the machine will be simultaneously controlled by the motor (blue) through a series of gears (green and yellow). As the arm is engaged (lowered to be able to rake balls down the slope), the trap door is lifted into the open position. When we move our machine around, we will raise the arm, which simultaneously closes the trap door. 
Pictures:

Isometric view, showing rotational axes for arm, trap door, and rear axle.

Isometric view

Side View; Front gears used to simultaneously control arm and trap door

~RANA.