Ball Busters Final Robot Bill of Materials

Item	From	Use	Price
1/4'' Acrylic Plate	Kit	Baseplate, motor mount	5.56
1/8'' Delrin Plate	Kit	Motor mount, front linkage plate, front plate, control box mount	8.74
1/4'' Aluminum Plate	Kit	Linkages	6.28
1/2'' Aluminum Square Stock	Kit	Front plate mount	2.20
1/4'' diameter Aluminum Rod	Kit	Linkages and axles	2.07
1'' square Al Tube Stock	Kit	Frame	4.71
1/4'' diameter Steel Rod	Crib Stock	Linkages
Acetal Copolymer Rod, 3/8" Diameter, White	McMaster (see below*)	Bushings	3.40
1'' square Al 90 deg. Angle Stock		Front Linkage Plate Lip	3.70
1/4'' diameter E-Clips	Kit	Linkages and axles	0.19
3'' dia Polypropylene Wheel X4	Kit	Wheels	5.72
Tamiya 70168 Double Gearbox	Kit	Driving motors	8.75
Tamiya 72005 6-Speed Gearbox	Kit	Linkage motor	13.25
Wire, electrical tape, connectors	Kit	Electronics
Velcro strips	Crib	Control box mount	0.10
#64 Rubber Bands 3.5" x 1/2''	Crib	Traction
.85 oz, 2-Part Epoxy	Crib	Attaching rubber bands	4.44
Stock Fasteners	Crib	Attachments
		Total	69.11
Purchases (mostly unused in final robot)		Supplier: McMaster-Carr
18-8 Stainless Steel Slotted Spring Pin, 3/16" Diameter, 9/16" Length	Part 92373A246	5.88 per pack	5.88
Multipurpose Aluminum (alloy 6061), 1-1/4" Square	Part 9008K151	1' length at 15.58 each	15.58
Galvanized Low-Carbon Steel 90 Degree Angle, Plain, 1" X 1" Legs, 1/8" Thick	Part 8968K32	3' length at 11.92 each	11.92
18-8 Stainless Steel Slotted Spring Pin, 3/8" Diameter, 3/4" Length	Part 92373A554	5.06 per pack	5.06
Architectural Aluminum Tube (alloy 6063), Square, 3/4" X 3/4", 1/8" Wall	Part 88875K31	6' length at 9.85 each X2	19.70
* Acetal Copolymer Rod, 3/8" Diameter, White	Part 8497K171	4' length at .85 per foot	3.40
Multipurpose Anodized Aluminum (alloy 6061), 1/4" Diameter	Part 6750K131	1' length at 3.41 each	3.41
		Total Shipping	26.13
		Total Puchases	91.08

Final Robot Report

Overview
Faced with a multitude of problems and inaccuracies on the first robot, Buster, we decided as a team that despite the limited amount of time, we would need to start over from scratch. The final product, Panic, was designed late Monday night, manufactured Tuesday and assembled Wednesday morning before the 12:30 deadline.

The Panic design took the concept of simplicity even further than what was attempted with Buster. While the overall strategy and MCM design remained essentially the same, everything else was cut down to a bare minimum of functionality. Despite this, the challenges of building a slotbot in 32 hours led to misfires and incomplete functionality which would ultimately lead to the elimination of Panic in the first round at the hands of Ghost Robots.

Functionality
As we had decided to stick with the original strategy and concepts in the redesign, Panic had in theory the same functional aspects as the final design iteration of Buster. The MCM involved two parallel three-bar linkages, both powered by the 6-speed motor, and joined by a large front plate that would be used to corral balls. The front plate moved in a circle, which was designed such that the lip would contact balls at just the right angle to avoid catching friction. The balls would be held in the front of the robot against a stationary front plate.

The double gearbox motor was mounted in the back of the robot for driving. Turning would be accomplished by running each motor in opposite directions, causing the robot to rotate about the motor. The front wheels would need to slip for this to happen, and as such were not fitted with rubber bands like the driven wheels.

Manufacturing
Panic was essentially born in the laser cutter. The many plastic plates used were all laser cut for speed and accuracy. The linkage bars were cut in the water jet and the two aluminum rails were manufactured on the mill. Finally, the lathe was used to create the robot’s bushings and shafts to complete the design.

Pat Milligan's Reflection

Patrick Milligan

ME 250 Reflection

Dec 9 2010

Note: Sorry this is really long! I had a lot of thoughts on this class that may or may not be interesting to you. A lot of the ‘what I learned’ consists of personal learning as a result of failure and probably isn’t broadly applicable. If you read nothing else, please review the suggestions. I put a lot of thought into these, and I think they are simple and can make a big difference!

What I learned and how I would improve

­When I entered this class, after about a week I decided that this class would be my easiest this semester. I had all the bases covered. I was in FIRST Robotics for all four years of high school, which included designing to a challenge, working under time pressure, manufacturing a design, and working with a team. I was in Physics 240, had taken MSE 250, had some exposure to CAD, and was comfortable working in machine shops. What did I stand to learn from this class?

Fast forward to today. As I write this, another team is in the process of winning $300, many others are celebrating the end of a fun and rewarding class, and I’m sitting on the side contemplating our excuse of a robot and hoping, hoping! that I squeaked by and passed this class. What on earth went wrong, what changed, ay, for goodness sakes how did I end up here?

There are numerous things, as I think back, that I could blame for my failures in this class. A lot of things completely outside of academics went wrong this semester. I was also overwhelmed by course load; I ended up dropping a class and a number of commitments after stress started seriously affecting my mental health. My team was full of fellow over-busy people and we rarely found common time to meet and work. None of us were very good at using the high-tech machines. We had small errors in our design that compounded into catastrophic ones. The list goes on.

But it is too easy to use these problems as excuses and simply move on. When I think about it, some patterns emerge that I can identify and improve on. Lack of focus is painfully obvious. Same for being overconfident in myself and my abilities, which killed my motivation to learn and improve. I also wasn’t a good leader; too often I accepted the first answer I heard instead of allowing my team members to work and perform their best.

To make a long story short (see the first draft of this essay), I failed as an engineer. I have heard over and over how important failure is in growing as an engineer, and I guess the three lessons I mentioned above are, for me, the results of this failure. If I have to do this class over again, I will already be practicing these lessons. In terms of focus, I cut out a lot of my activities that weren’t as important to me to free up time and dropped a class so that I could do better in the other three. Being overconfident in myself was slowly shattered this semester as well. And for being a good leader, I learned many important lessons that I will use frequently.

That is all well and good. I’m glad I learned from the experience. But as I look at this, one question comes to my mind over and over: ‘where is the line drawn?’ Where does pushing yourself to do better meet not stretching yourself too thin and focusing down? Where does the problem of over-confidence meet the problem of under-confidence, and which is worse? Where does being a leader meet taking too much responsibility? I’ve been on both sides of all of these equations at one point or another. The only answer I can come up with is: let experience be your best teacher, and this is one more experience to bank on and relate to.

Course Improvement Suggestions

Shop – Shop training needs to be more comprehensive. While Bob and John realize that the one-hour introduction isn’t enough, the only caveat is ‘just get us to help you’. That works well if you are the only one in the shop. Otherwise, your options are –wait a half hour, get help and get the first step right, then wait again for help with the second step; or –try to do it on your own and risk screwing your part up or getting the hook for improper/unsafe procedure. Something has to be improved.

Here’s one suggestion. Make it an early assignment to produce a part on the mill and lathe. Give students an engineering drawing with a simple part that requires mill and lathe work, and include very detailed, very specific instructions for how to set up the mill and lathe to do the work. Bob and John wouldn’t have to be bothered if the instructions are good. Try to include the procedures and skills that students will use most often in the project.

This would help tremendously with confidence and understanding of the machines, both of which were very lacking among students during the project (especially at the beginning, which I believe was part of the reason my group fell behind).

Lectures – Presentation of lecture material could be improved. There has to be a better way to get through it all than a 90-minute, 60-slide, straight-shot lecture. It just gets really difficult to pay attention and think about difficult concepts after a while when, frankly, it is flat out boring. I’m not a student who doesn’t care; I have a 3.8 and I rarely skip or sleep on class, but I struggled with the lectures. Most other students I talked to expressed similar opinions.

Two simple suggestions for improvement:

-Pause and give students a 5-minute mental break in the middle of the lectures. My eng101 professor, Alex Bielajew, strongly believed in this concept, and I agree that it made it easier to pay attention for the full period

-Use different methods of presenting material during class. To reference eng101 again, the professor frequently used powerpoint slides, writing on the whiteboard, physical examples, having students do examples in front of class, and actively programming during class with student input. Using the same method of teaching over and over again is like driving 40 mph through Kansas. Try to adapt some material in each lecture to a different format.

Finally, a general suggestion for the class. This may not be your responsibility to determine, but I believe the scope of this class is too wide. The instructors are trying to teach a huge range of topics, and each instructor understandably wants students to learn a lot about that particular subject. Prof Hart emphasized comprehensive design skills, my GSI Davor wanted us to be excellent at CAD, the lecturer Mike Umbriac wanted us to be great at precision design and engineering drawings, the shop instructors Bob and John wanted us to be excellent machinists. The material covered ranged from MSE (an entire class, MSE250, in a single lecture) to perspective drawing skills to mechanical components to electrical circuits and more.

The result, in my mind, is that none of it gets covered and learned as well as instructors would like. This is a 4-credit class, not the entire Michigan Mechanical Engineering department. If it is your responsibility to decide content for this class, I would strongly suggest narrowing the list of topics and focusing a bit more.

Individual Reflection - Gavin Lim

ME250 was an excellent class. I was able to acquire valuable information, experiences and hands-on manufacturing skills.  Thanks to Professor John Hart, Assistant Lecturer Mike Umbriac & GSI Davor Copic for providing such great assistance to our team throughout entire process.

DESIGN & MANUFACTURING

Our machines had to achieve specific requirements every time a certain milestone is reached. We started off with brainstorming a lot of concepts, sketching these concepts by hand. We narrow it down to one or two and focus on choosing the strategy and then following that, a specific module. During these design phases, we have to consider a lot of factors affecting the performance of the robot such as materials, manufacturability, choices of gear ratios and so on. It was very troublesome but with the help of the GSI, we managed to finalize our module, strategy and concept and draw the entire robot on solid CAD model. At this point, we are able to produce solid CAD drawings of the entire robot, bills of materials, an engineering drawings and a manufacturing plan.  With these achieved, we can start manufacturing.

We manufactured the parts according to the engineering drawings and the manufacturing plan. The engineering drawings show every dimension of the part to be manufactured whereas the manufacturing plan guides us through the whole manufacturing process. The machineries available to usage were the band saw, lathe, mill, drill press, water jet, laser cutter and other equipments that can be checked out at the machine den. Only the drill press can be used without signing up for a slot, however it can be of high demands sometimes whereas all the other machineries requires signing up no more than once a day. We learnt that each material is to be cut with different speeds/RPMs for e.g. aluminum is to  cut with high RPM of around 300 whereas steel at around 50-100. And, it’s just interesting to know what or what not to be cut by the water-jet and laser cutter and see how accurate the finished product is. We learnt that manufacturing a part is very time consuming and also requires very detailed planning. Therefore, it makes more sense to purchase that particular part.

TEAM WORK & MANAGEMENT

In teamwork, we learnt to divide and assign jobs to every member of the team. Every member will bring together the finished parts where one member will put everything together. The assignment will be examined and run through by the team to make sure everything is complete. Management wise, we will assign the part where the team member is good at and with everyone’s agreement. There will be times that a team member will not be happy with the assigned task but this is when we learn how to compromise and work as a team. With good teamwork and team management, it will be easier to get stuffs done.

HOW THE COURSE CAN BE IMPROVED

I’m personally happy with the course itself. I just thought the shop training can be more detailed. It would save us more time if written instructions & recorded videos posted on Ctools such as how to use the lathe, mill, water-jet and laser cutter. Students new to these things will have an idea what to expect during the hands -on training. And also, it will be good if the shop can consider opening till to later at night.

HOW YOU COULD HAVE IMPROVED IN THE COURSE

I could have improved in this course if I had spent more time absorbing the information in lecture and do well in the exam. And also, if we as a team, were able to be more organized and start work earlier, things would have been much more easier. We should have allocated our time more wisely. Yes, I feel that being organized and starting work early is very important in this course. 

Individual Reflection - Tasha Stearns

During the course of ME 250, I learned a lot about the complexities of working in a group and learning how to use a multitude of new technologies, including SolidWorks and all the machines we used to manufacture our robot. It was incredibly chaotic and time consuming, so this is a grand opportunity for me to sit down and make sense of it all.

Now that I’ve actually gone through the process, the charts used to explain how we should approach this project make more sense. To make an effective product, you need to consider what exactly it needs to do and how it should do it. These are very important decisions to make because they are the foundation for the rest of the project and should be given an appropriate amount of time for thought. As for teamwork, this semester gave me an important lesson: not everyone will contribute the same amount of work. This isn’t a bad thing, it is just the realization that there needs to be a group leader, or at least someone to focus the whole group. Generally this person will have the best idea of the overall project so they must bear the responsibility of guiding the rest of the group. While some positions in the team have slightly more responsibilities, they are still comparable to each other. In order for the group to function with cohesion, everyone needs to be involved, whether that simply means being at the meetings to follow the progress so that they may input later or that the person is giving a lot of ideas for the project. Either way, it is essential. While it is very important to have roles in the team and recognize that some are weightier than others, it is also very important to have a time line. The time line is the basis for time management, and although it seems trivial in the beginning it is also a very, very important concept to have down.

In terms of manufacturing, I have learned the lesson of (as Bob would call it) KIS: Keep It Simple. When designing in CAD it is easy to forget the physical limitations imposed by the way we manufacture the parts. Each hole takes time to place with the precision needed, and the same goes for every other feature we need to manufacture into the parts. It is also very easy to overlook small but important details, such as: when placing holes you must also consider the radius of the bolt head/nut or any other fastener.

With these lessons, it is easy to look in hindsight and point out where we messed up and how we could have done things much more efficiently. In the beginning it seemed like we had so much time to design our robot, so the reality didn’t hit us until much later. We didn’t use our copious amount of time in the beginning to adequately plan out and design our project. We failed to realize that what we needed to do was get a solid idea of our robot in place and turn that idea into reality first through SolidWorks and then manufacturing. SolidWorks is the place where we can iron out all the small details of our robot, which we did, but it happened much later than when we needed it to happen. Most of our problems stemmed from the fact that we didn’t plan accordingly and use our time wisely in the beginning.

Team Ball Busters

Reflection on ME 250 - Dhruv Sekhri

Mechanical Engineering 250: Design and Manufacturing is one of the most unique classes offered in the engineering school. It has taught me several important lessons and has given me great insight into the engineering profession. Unlike most of other engineering classes, ME 250 actually gave me hands on experience that you cannot simply learn by reading a book and doing homework problems. As great as this class was, there are still ways that it can improve. Overall, this was one of the better classes I have taken at the University of Michigan.

From working in the machine shop to completing the homework assignments, I felt I was constantly learning and exploring new things. Splitting up the semester into two parts with the first being based on individual performance and the second based on teamwork gave me a more in depth look into the several aspects of engineering. Formulating my own modules and concepts during the first part let me explore my creativity while understanding the different facets of the game a lot better. Meanwhile the homework assignments let us challenge our conceptual skills and made us consider the mathematical aspect of the planning stage. More importantly I learned that even if you are or will be eventually working with a team on a project, it is key for you to formulate your ideas and opinions about the game that you can later debate about with your team members. In order for brain storming to be most effective, each team member needs to have his or her own concepts that are unique in their own ways. Also, it was important that we learn about the basic engineering concepts prior to working in a team setting. Although we did learn about several of the engineering concepts later in the semester, it was important that the professors established somewhat of a base that we could use to fabricate the ideas for our robot.

As important as the first part of the semester was, the second part was equally if not more important. We not only got to work in a team setting but also received extensive experience in the shop. The initial part of this segment involved receiving training for the shop and spending countless hours designing our robot. Even though the training we received went over the basic parts of the machines, we weren’t able to create any complex parts similar to those we could be using on our robot. I feel like if we received some more training on the machines, the building of the robots could’ve gone more smoothly. Also, I learned that the designing stage of a product is almost more important than the actual manufacturing part. If the parts have been designed accurately then their manufacturing should not require a lot of time. We did not understand this at the time and were severely troubled during the manufacturing stage. Moreover, our time management wasn’t ideal either. We hindered our progress by delaying several of the major decisions. This delay in our schedule caused us to push back our manufacturing, which did not help us in the long run. Although we finished our project on time, our manufacturing was not up to par. Regardless, I learned a lot about the manufacturing process and working with machines to engineer parts. Since I didn’t have any experience working in the shop, essentially was new to me.