Bills of Materials

https://spreadsheets0.google.com/ccc?key=t-AflDykkJJN0-yTzA4RoFA&hl=en#gid=0

https://spreadsheets.google.com/ccc?key=0Ah3SVAtSqSsNdFBJbmdHS1lyckhqWjBRdG1XelV6RGc&hl=en#gid=0

It's been a good run...

Well we ended up losing in the first round, thanks in no small part to some discrepancies between the given and actual dimensions of the table, but we did pretty well for how little testing we got to do, and we gave everyone a treat when our locking arm overpowered our opponents' so much it almost flipped their slot bot out enough to topple their rover. We wish we could have changed some things, but all in all, I for one am proud of Sei Jin's Rejects.

Our final design actually removed the blocking wall on the stationary bot, and the lifting arms on the rover that are pictured above to fall in the legal weight limit and avoid breaking rules about blocking.

Our final design was activated by driving the rover off of a flipper. This allowed a bar to rotate which deployed the locking arm, and closed the circuit to give power to the motor which advanced the scoring arm. A pin in the starting end of the scoring arm machine held the scoring arm up in the allowed starting zone until the arm moved far enough away the pin no longer held it up. The rotating bar also lifted a cover which held the locking arm back allowing potential energy in rubber bands to launch it at the flipper.

Our final rover design was cut down drastically so we could make our weight limit. The flipping arm mechanism was removed altogether, and the back flap which was able to move proved ineffective at moving the squash balls. Due to its heavy weight, the rover proved ineffective in the competition, being fairly slow and unmaneuverable. 

We all wish we had more time to test our design, but I'm proud of our work. We were even  chosen as having the best manufacturing. Finally, Sei Jin's Rejects would like to thank everyone who's helped us in our project.  

Personal Reflection

This course was so stressful. As I am taking 18 credits this semester. Sometimes time is very limited for me. As a civil engineering student, this is my first time to touch manufacturing design. At first, I feel stressed because of lacking experience. Later I find the content of the class help me to understand a lot, especially the work in ME250 shop. I have a chance to really know the process of Mill machine and lathe.

I think my teammates do a good job. They gave me a lot of help in manufacturing and designing. I tried my best to come to class although I have time conflict with other courses. I think I do what I can do. The biggest points I felt is that our team don't have a good time management. That caused no time for test and modification. That is the problem.

For the class, I think the content is good, but teacher covered so quickly and we don't have enough example or experience to go over the material. In the project, I hardly combined the lecture content with the real process.

Course Reflection

It has been a long and rough semester. At times it felt like it was all in vain,and my head was going to explode. This was never more true than when we lost our first round because our scoring arm stopped moving due to irregularities in the slot size. Looking back now though, if nothing else I’ve gained some important experience that will make me that much better off in my next design project. While I believe I definitely have gained from this class much of it has been in a non-ideal way.

With regards to design and manufacturing, I am afraid I did not learn nearly as much as I had hoped to. I felt as if much of this aspect of the course was brushed over hastily, and not effectively linked to the assignments. I focused too much on the project and struggling to catch up with CAD, manufacturing, and the homework assignments caused me to lag behind in the lecture material. Furthermore, I felt as if I was not given exercises that effectively helped me learn how to apply the principles taught in class. While more example problems in class, and better exercises would have helped, these could only help so much, as this material is fairly abstract and not applied as straightforwardly as say statics and mechanics. What it comes down to is that the next time I encounter the concepts and material from this class I will have a better background in them, but not a mastery. What I gained the most from in this class was simply the experience of being involved in a serious design project. From working with CAD, to learning basic metal manufacturing techniques, to working with a team on project requiring highly specialized and technical background this project was my introduction to many aspects of engineering projects. This team experience was quite different from my past teams, as allowing the choice of our own teams gave me teammates who I was able to rely on more, and the different requirements of the project allowed for more specialization of roles as is normal in engineering project teams. Finally as far as time management goes, I do not know what I was doing poorly or how to fix it, only that I was doing a poor job, because I felt as if I was working nonstop this semester, yet I still received grades that seemed disproportionate to the time and effort that went into the projects, which likely indicates that the time was not being used effectively, in whether it be the working, or class time. This is my main concern coming out of this class, as workloads will not be getting any lighter, and material is getting more complicated.

All things said and done, I am not very pleased with how this class turned out. I came into this class with high expectations, but feel as if given my relatively little prior experience, the sheer amount of material covered, and having to divide my time between other classes, those expectations never had a hope of being a reality. Short of ignoring my other classes, I wish I had tried to assert my desire to be more involved in the actual design of our machine even though my lack of ability and experience in CAD limited my ability to.  I am glad I gained what I did from the class though and while extremely time consuming and stressful, the project had its moments where it was even fun. I hope to continue my education in design and manufacturing, even though I’m actually an electrical engineer. It’s been fun, but I’m done with blogging I think

-John

Course Reflection

Marc-Andre Henry

When I first signed up for ME250 I was excited that I was finally going to be able to apply what I learned in my other classes to create something. I was previously informed that this class would be a lot of work, so I knew that I would have to commit a lot of time. The purpose of this class was to teach us the design process, manufacturing methods, team work, and engineering. I had previous design and manufacturing experience and this class further refined my skills. I had previous CAD experience, but it was nice to learn a new program. This class helped me learn how to design parts that were producible by inexperienced machinists. I learned a lot about bearings and linkages in lecture which was useful in designing our project. I found out that CAD can take a very long time and sometimes, you have to make different versions of the same thing to achieve the desired results. I enjoyed learning how to use the laser cutter and water jet, because they were very useful in the building of our project. The most difficult part of this class was the fast paced build cycle. What made the limited time especially difficult was the limited shop time. I also learned how to design within constraints (Rules) and a budget. As a team we had to adapt to each other’s class schedule and personal lives. Being in a team like this is a great experience, but it also requires a lot of patience and time. If I were to start over, I would force my team to finish earlier and test the hell out of our machine. I would find a better way to manage my time and become more efficient.

Even though I learned a lot, I feel that the class could be improved. I felt that we spent too much time going over the design process and creativity. We should have formed groups earlier and started the project a few weeks before the time we actually started it. I think that if we were given a budget equivalent to the cost of the provided kit, then teams could have been more creative in their design. A lot of the provided parts were not very useful and I feel as if teams could have chosen to use better motors and gear boxes. Another problem I found was that the provided tables were not built like in CAD and were substancaily different and caused our team many problems and caused our machine to fail. Another thing I did not like was that the rules kept getting changed which made it difficult to finalize a design and it ended up costing use time. I wish we could have done the motor lab earlier so that it could have been useful to our design process. The bike lab was not necessary and we could do without. If more time were given to test, more of the teams would have been successful at competition including ours. So basically the things that I think need to be improved are to start the project earlier, let each team chose its resources, and to have a competition table built to specifications. Overall this class was a lot of work, but I did learn a lot so I think it was a success.

Personal Course Reflection

This class taught me a lot about what goes into the designing process. I learned that one has to think about almost everything from how we are going to machine a part to leaving enough room for a screw head. It was definitely an experience unlike any other I have had before. As for the manufacturing side, this experience has given me a lot of practice with machining on the mill. It helped me work on techniques and also reading engineering drawings. The machining experience also gave me a feel for how important machining tolerances are and how to properly tolerance parts based on how precise they need to be. Also I learned to plan for the worst and hope for the best. As for the teamwork side, the project helped me realize that a good group effort up-front leads to a much easier end result. When everyone works together from the start it just keeps rolling throughout the project. Time management was key to this project and was definitely eye-opening when realizing how much time and work needed to go into this project from the machining to the homework and MS assignments. Budgeting for time was necessary in the project and that was evident mid-way through. Time lost was not able to be regained and with all other classes piling up, it definitely hit us hard.

One way the course could be improved is more instruction. When leaving this up for such subjective grading, it is hard to interpret what the grader wants to see. I understand that its all about how well you do relative to others, but at some points we had to guess what was meant by the instructions on some of the homework. Even asking the professors for help was vague and unclear. Also, I feel as though there was a lot of homework and lab projects that did not pertain to the material in lecture. It was not connected well and the relation between lecture material and homework could definitely be improved. In addition, the lectures on the different mechanical components was nice but boring. Maybe going through a class or lab design of a simple device would have been good in order to get a general feel for the design process. I think that the material on the exam was briefly touched on. The lectures gave us quite a bit of material and didn't focus enough on any of it, which made it difficult to know what to study. With so much information, it was hard to figure out what was going to be on the exam. Also, starting off with more about the design process would have helped our team because we would know more about how to properly design something instead of making drastic changes down the road near the end of the project.

One way I could have improved my performance in this class was putting forth more effort in the beginning with the homework and getting a head start with the teamwork. We waited a little too long to dive into our project, and when we did, all of our other classes started to get heavy as well.

We developed three rover designs

Final design
Second Design
First Design

Final rover design

Scoring Arm

Now that the competition is over we can show our completed CAD without the possibility of having other teams adapt to our design.

And We're done...

Here are a few pictures of our rover.

Update for week of November 28

This has been a really busy week, as we finish up our machine. We have spent hours machining, polishing and assembling, but have finally finished. Our largest tasks completed this week were the redesign of our motor mount on the scoring arm to accommodate the bigger motor required to drive the threaded rod that advances the machine effectively, and the assembly of our rover and locking arm.

To finish our machine Jake, Marc and I were up all last night fine tuning the joints and making sure all the pieces fit together. Pictures will be posted soon to show our finished machine. In a short while, we will be presenting our machine to Sei Jin for Milestone 9. What lies ahead for us this week is fixing up our machine and testing it before the seeding on Wednesday, and uploading our team video.

Almost done...

This is our MCM. We found out after testing that one planetary gearbox is not enough to move the balls in the slot. To fix the problem we will add an additional motor by changing the pillow block design to accommodate an additional drive gear.

Update for week of November 21

This past week, before leaving for Thanksgiving break, we finished the scoring arm module of our design. After running into some initial problems with the exact dimensioning of stock pieces, and a lot of sanding, we assembled the module to present for MS8 on Wednesday. Testing of the assembled module exposed some flaws in the positioning of the motor, and torque calculations. Solutions are being devised and tested.

After our scoring arm was ready, we finished the designs for our rover and locking arm. This week's schedule will involve machining and assembling these modules as well as testing for the entire machine. Our machine shop use is starting to wrap up, as much of what is left is to be done on the water jet cutter, and then simply assembling the pieces.

Update for week of November 14

Lecture has officially concluded and we have turned all ME 250 efforts towards our project. We have been working on completing all of the components of our most critical module, the scoring arm. The two end pieces of the rail support and the largest section of the arm itself were completed last weekend, with all of the smaller and more complex parts being the focus this week.  Here is a more detailed list of our tasks completed this week:

-Machining of many of the components for the scoring arm

-Researching the most realistic spring configuration for the locking arm

-Beginning planning of fabrication of the rest of the the machine

On Monday this week we'll be presenting the first 3 components of our scoring arm to our GSI for milestone 7, and we will be finishing our scoring arm so that it can be presented Wednesday for milestone 8. This week will consist of a lot of design and machining on our parts.

Update for week of November 7

We have begun fabrication of our machine, and split up the remaining logistical duties left before we finish our project. We have purchased most of the additional raw materials we will need, only needing a few more specialized parts, like springs. We hope to have fabrication of all components of our MCM, the scoring arm, completed by the end of this week.

Machined Parts

We have three parts machined and completed.
The two short parts are the guide rail posts and the long square tube is the scoring arm housing.

Update for week of October 31

This week we completed our MS6, the review of our most critical module. We choose our scoring arm, as it is our main method of scoring, and the most complex component of our machine. The included

-Finalizing the CAD and engineering drawings of the module
-Bill of materials for the scoring arm
-Planning out the machining process of each of part

This weekend Marc will be obtaining the extra materials we will need, and we hope to finish most of our main machining this coming week.

This week we created a schedule and we started to finalize our CAD model. We also started our bill of materials.

Our Team Schedule 0ApzqcbKTzzOHdFF3elpDZDB2cnpieUJnMUhHNW1yWnc&hl=en&authkey=CKKo5asC goo.gl/rZ8l

Introduction

We are Sei Jin's Rejects, a team in ME 250 at the University of Michigan. This blog is going to document our engineering, manufacturing and dominance in the Slotbots II competition this semester.

Our current CAD design:

Our strategy is to lock the flipper open for us, so that only our machine can score in the slot, while another module puts secondary focus on either defending our opponents cone, or scoring on the top of the slot. The machine we have designed to do execute our strategy consists of a locking arm which deploys to push the lever open, a scoring arm which will lower into the slot and push the balls to the goal, and a small rover which will push balls into our cone, or off the table, as well as defend against our opponents' machines and interfere with their strategy.

Sketch model used to demonstrate our design on the game arena:

Soon we'll post a link to our planned schedule for the rest of the semester