Kyle's Reflection

Now that ME250 is over and I have had time to reflect on the course, I have come to realize many things. Firstly, and in my opinion most importantly, I now am sure that I have chosen the right path for my education by majoring in Mechanical Engineering. Although ME250 was hectic and frustrating at times, I now know I thoroughly enjoy the design and manufacturing process. On more of a fundamental level, I have learned a great deal this semester. I now have a strong understanding of basic terminology such as the difference between a tapered bearing and a deep grove bearing, and more importantly which one is more applicable to a certain design application. Understanding different methods of machining parts is a very valuable skill that I have taken away from this class as well.  For instance I learned what circumstances it is preferable to use a mill instead of a hand drill or drill press to drill a hole in a piece. It is also important to note that each machine has their limitations. For instance some rods are simply too small to cut down on the lathe. These limitations should be taken into account during the design process. This semester has definitely taught me about the importance of a complete and thorough design. The design is the backbone of manufacturing and without a complete design (nuts and bolts included) the project will not proceed smoothly.  

ME250 is a very involved class and can at times the project can appear daunting, however it definitely helps to be working with a team. During the design process it was interesting to see the differing approaches to most everything we did. Ranging from the strategy selection to the sketch model down to the actual manufacturing of the parts, each teammate had their own way to go about things. This was not a bad thing however. It was a good way to lay out our options, analyze the pros and cons of each option and come to a collective decision on which direction to go. This is a valuable experience because it is how the real world works. Some might say that working with a team affects an individual’s grade too much. I disagree because not only were there plenty of individual assignments, but being able to adapt to others and work in a team environment is a very important skill to have in the real world.

Time management is a recurring theme in ME250.  Milestones helped to keep students on track. However a part of the course that I found frustrating however was the how much had to be done between MS8 and MS9 in a small amount of time. Admittedly, it is each student’s responsibility to properly schedule out his or her project, however the schedule is a bit deceiving. At a glance it appears there is a week between needing to have the critical module complete and needing to have 90% of the machine complete, however with Thanksgiving break taking up four days of this week, there was only three days to accomplish this. I feel more of a forewarning of this could help future students. One other area I felt could be improved was the use of controllers in the final days. I think a sign up sheet for times with the controllers on a Google doc could be a very useful tool for future students.

My team could have improved our performance in two major ways. One is time management. We left slightly too much to be completed within the final days which created some chaos. We also should have had more of a simplistic design with a complete and perfect Solid Works model earlier in the class. Overall I feel that we worked well together and I enjoyed the class thoroughly.

Final Bill of Materials

#	Description	Use	Dimensions	Supplier	Part #	Other Details
1	Aluminum 1/16th thick	Blade	12”x18”	Kit
2	1/4th Acrylic Plate	Blade Arms, machine top	12”x18”	Kit
3	Flanged SS bearing	Drive axle shafts	¼’’ ID, ½’’ OD	Kit
4	3/8’’ Round Stock	MCM axle shaft	18’’ long	Kit
5	¼’’ Round Stock	Planetary gearbox drive axle	8’’ long	Machine Shop		Stock from the machine shop
6	1/8’’ Delrin plate	MCM blade, machine bottom	12’’x12’’	Kit
7	Aluminum Plate, ¼’’ thick	Chassis sides	6’x18’’	Kit
8	Aluminum tube stock	MCM axle pillow blocks	¾’’x ¾’’ x 1/8’’ wall	Kit
9	Flanged brass bushings	MCM axle	¼’’ ID, 3/8’’ OD	Kit
10	E-Clip retaining ring, ¼’’ Dia.	Constrain MCM axle	¼’’ Diameter	Kit
11	Spur Gear	Planetary gearbox transmission	¼’’ bore x 1.083’’ OD	Kit	A 1M 2-Y24024
12	Ball casters	Front guide wheels	13/16’’ tall by 15/16’’ wide	McMaster	6460K21
13	Pololu 1576 99:1 Metal Gearmotor	Drive Motors	25D X 54L	Crib
14	Tamiya 72001 Planetary Gearbox Kit	MCM drive motor	N/A	Kit
15	5 #4-40 Set Screws	Constrain MCM gears to planetary output shaft; constrain axles to drive motor shafts	#4-40	Carpenter Brothers Hardware	N/A
16	JB Weld	Constrain wheels to drive axle; constrain front bumpers to machine sides	N/A	Carpenter Brothers Hardware	N/A
17	L-Brackets (3 packs of 4)	Attach machine sides together	1.5’’ X 1.5’’ X 5/8’’	Carpenter Brothers hardware	N/A
18	1/4-20 bolts and nuts	Attach machine sides together	¼-20	ME250 Shop
19	Dowel Pin	Constrain MCM “silencer” to planetary output shaft	Approx. .077’’ diameter	ME250 Shop
20	#6-32 screws	Constrain the MCM arms to the MCM axle shaft	#5-40	Cage	N/A
21	Velcro	Constrain rear of the machine to our sides and allow for quick service	1.2 pull-apart, 200 cycles, 1’’ wide .188’’ thick	Kit
22	Wheels	Drive the machine	3’’ Diameter	Ebay
23	¼’’ steel round stock	Machine axles	¼’’ diameter	Kit

Purchased Items:

PURCHASE LIST
Item	Company	Total Price
Team Associated 21065 18MT Mounted Wheel/Tire/Insert	Amazon.com	$14.89
JB Weld & V115 IRON, CORNR 11/2X5/8	Carpenter Bros. Hardware	$11.21
Nuts/Bolts/Nails/Screws	Carpenter Bros. Hardware	$2.27
4 Pack Corner Brace Satin Brass	Home Depot	$6.32
Gimp/Basswood	Michaels	$5.06
Vinyl	Jo-Ann Fabrics	$0.70
Caster Wheels	McMaster Carr	$17.78
	TOTAL:	$58.23

Kolin's Reflection

               I came into ME250 thinking that the design process was something that you could learn easily, and then it was all about creativity past that point.  I have learned throughout the semester that this is not the case.  While creativity is certainly an important aspect, I came to realize that design is something learned through practice and failing.  If I could redo my project, there would be a lot that I would do differently.  As I drew sketches and made solid models in the beginning of the year, I had no idea how difficult it would be to manufacture any of it.  We designed our machine in a way that we thought would be easy to manufacture, but it turns out there was a lot more underlying complexity that we would not understand until we began to manufacture and assemble it. 

               I also learned that while anything can be manufactured, you really need to consider how it is going to be manufactured when designing anything.  We initially designed modules with CAD software without considering how we would achieve the desired geometry.  Once we modified them to use the stock material, we still failed to consider carefully enough how it was all going to fit together.  I think one of the overarching lessons I learned was something Connor said in his GSI design presentation that I didn't take seriously enough at the time: the importance of planning out where and how you are going to fasten things together.  We used a series of L-brackets to fasten our chassis together, and it is one of my biggest regrets of the project.  While I have effectively used L-brackets in the past on projects involving wood, I had no idea how much more difficult it would be to use them with metal.  The holes drilled had to be so much more precise and no matter what we tried there was always a little bit of misalignment that wouldn't have been an issue on a wooden piece.  The amount of precision required in tolerances when working with metal parts in general was something that surprised me and was definitely a wake-up call.

               Teamwork was another thing I gained a lot of insight into throughout the semester.  It was challenging to divide up the work evenly among us while also playing to our individual strengths.  I feel like we struggled a little bit with it at first, but got a lot better at it towards the end.  We also improved in our time management skills.  In the beginning of the semester, we would not treat lab time as being very important.  However, by the end, we were effectively utilizing our lab time as well as any other time we met outside of class in order to finished things on time.

               I think the course could be improved by starting the manufacturing process earlier.  While I liked how we took the exam early and didn't have to worry about it later, I feel like we were allowed in the shop too late in the semester to effectively accomplish all we wanted to.  At the same time, I think my group and I definitely could have made better use of shop time in the beginning of November because we found ourselves rushing a lot that last week.  It seems like all the teams had this problem though.  In hindsight, I think all the stress in the last few days trying to get components to work was a positive experience because it simulated some of the real life pressure that we might face before a deadline for a project working for a company.  Another way I would improve the class is the make the lectures a little more interesting.  I feel like they weren't very interactive and could get dry at times because they were so long and there was so much information to process at once.  More cool videos and simulations would help as well as getting students more involved somehow.

Steve Orloff's individual assessment

Now that ME250 is over, I guess it is time to look back at what I learned. When I initially thought about this question, my mind went blank. I came into ME250 with some previous design experience having been on the student team UM::Autonomy, and I think this might have contributed to some of the problems I had and some of the extra rework I needed to do. I’m sure you’re familiar with the attitude of “been there, done that.” Honestly, that’s what I came into ME250 with. Without much description, lets just say it was a crappy attitude to start with (and I should have known this, but I guess I was vain). I learned more than I could have imagined about the design process. The biggest, and most important thing I learned, is to make the solid model as detailed as possible to start with. This includes brackets, fasteners, motors and motor fasteners, and all holes. It makes assembly 100% easier. The biggest area I feel our team struggled in was actually putting the machine together. We had great ideas for transmitting power to axles, constraining gears and shafts, but we had more than enough problems actually putting the machine together because we didn’t add fasteners or holes for fasteners. This led to a lot of poor fits and a few extra holes. Additionally, I feel our team went for a little too much complexity and should have focused our design around simple and robust. The complex design caused us to put in a lot of hours building and assembling modules which really didn’t perform that well at the end anyway. Sometimes, the phrase “keep it simple, stupid” is more than just a phrase; it’s a great design principle. As far as manufacturing is concerned, the biggest thing I learned was to start building early! Our team managed to get into the machine shop about a week after it opened for 250, but I really wish we had started the first day it was open for 250. We found a lot of the parts that we initially thought would be easy to manufacture were rather difficult and often required more than one session in the machine shop. This was problematic because, while specific to our machine shop, it’s fairly hard to get a machine in the ME machine shop sometimes. Needing more than one machine shop session per part, as well as a busy machine shop, led to a few delays which caused us to begin assembly fairly late. Lastly, one of the biggest things I learned is to step back and let others do what they do best. I know I have a problem with being “controlling” sometimes; I work well with others and value my teammates input, but sometimes when things aren’t going right, I tend to start ignoring other opinions and going off what my gut is telling me. This is fatal flaw because two eyes (or more!) are always better than one for complex problems. When I stop listening and thinking critically, things will go wrong.

ME-250 course improvement

My biggest comment on this has to do with how material is conveyed and given to the students. In short, lectures suck. I’m sure you’ve noticed how the attendance throughout the semester dwindled down to 25-30 every lecture. In some way, you should try and convey the material to the students in a way other than standing up on a stage and lecturing for 1.5 hours. It’s boring, it’s monotonous, and it doesn’t really promote learning. I’m not sure how you would best go about changing this, but it is something to think about.

My course improvement

 Honestly, I should have probably spent more time on the material, but I didn’t. I had a busy semester with a heavy course load, and it took a toll on the amount of time I spent on learning the ME250 material. I feel I did fairly well at learning the material, but I guess time will tell if my grade reflects that!

Paint Job

We've decided to go with the matte black color for our vehicle...


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Team Video

Here is the final video for Team 36 OZ.  Enjoy!