Shaft

The shaft for our cart were too small for a tight fit with the wheels. Instead we drilled holes through both the shaft and the wheels and put pins through them. This way, the shaft will spin with the wheels and we don't need a tight fit. We made the pins out of the steel plate by cutting it into long, thin pin like shape.

Final Reflection Ben Hubbard aka Tay

The part of the class that stuck out most to me were the first couple lectures on design. I thought these were the most important and the lectures are very clear and easy to follow. The steps and tools such as FRDPAARC and CAD to help break down and visualize the idea are what I will remember best of everything, and the recursion of the steps. Design heavily impacts production, so thinking ahead is very valuable. The most time should be spent early on with strategies and design to make things easier, and also so that you can test and be prepared when things go wrong. Also design often times takes thinking out of the box and applying the design principles to many aspects of the design.

Teamwork is the strongest tool we had, but it could also be a hindrance. Sometimes our group worked best when we split up the work to be done by individuals. Team chemistry is an important part of a team and everyone has to be on the same page working in the same direction for the team to be most successful. Teamwork is also something that needs to be practiced and you need to go into it with an open mind.

Time management is half of the battle in design. The other half is restricted creativity, but you can’t really learn creativity. A huge part of time management for this class was managing your time to fit with other people’s schedules because it is a group project and to be free when the shop is open. This means managing your time with other classes and your personal life, which can be very difficult.

This is my first semester at Michigan and the College of Engineering, so the workload and style of learning were new to me. I felt like a lot of the content was left ambiguous for creativity, but I needed more structure. Often times in class being able to see and visualize things was the most helpful, such as the first time we got to actually see the real arena. When I was first creating my ideas, I did not even know what we were and were not able to do in the competition, so spending some more time early on understanding what we’re trying to accomplish would have helped a lot. The advice, quotations and cartoons are often what people remember, so choose them well and be creative with the ways you’re teaching to people because the lectures became very repetitive and boring after a while, and design is a very interesting subject.

I could have done a lot to improve my grade and performance in this class by managing my time better. It was difficult for me to meet with the team early on because I was at water polo practices and away on tournaments so much. I should have buckled down on my work in everything else to be there for the team. Also I could have gone to Office hours and reviewed more for the exam. Overall I learned a lot, regardless of the grade or machine.

Quoc-Anh Nguyen- Reflection

The major thing that I learned in ME 250 was how to use CAD. Many companies today uses CAD for design and we will be using class throughout ME 350 and 450, so I think we should have dedicated more time towards learning how to use CAD.
As for design and manufacturing, I found out that it was a very quick and time consuming process. Even after making all the designs and calculations, there could be many things that prevent the manufacturing of the design. Material resources were one of the largest obstacles. One can have a good design, but without the material, the design was useless. Thus, I think the student should have an earlier list of the materials in the kit. This is because many of us do not have cars and so we cannot buy other materials. Also out team had a big problem with bending the aluminum plate for our cart. Our plate was much longer than the length of the bending machine so we had to do it by hand. So I think students should be given the length of the bending machine, the dimension of the laser jet and the dimension of the water-jet so we can make better preparations before finding out that we cannot make our part the way we planned.
Teamwork is an important part of this course, and everyone needs to do their fair share in order for the team to succeed. Everyone should be advice on the importance of picking their teammate. Also we should be given a team evaluation at the middle of the semester to see how well each team is working together and to motivate each member to work harder.
Time management was one of the hardest things to keep track of for this course. Since each team members will have different classes to worry about and scheduling time, an outline of when everything is due should be posted from beginning of semester to end so each team knows exactly what to expect. I learn that to have a schedule that everyone can follow will keep the team and each individual on track.
Many of the homework problems were too hard and had many ambiguous assumptions. Without going to office hours, most people would have a hard time figuring out these assumptions. Homework felt more like office hours work. Anyone who goes to office hours will most likely get a better score than those who stays home. Also, we did not do any calculations during class, but we had many calculations to do in homework. Maybe we can do some example problems similar to the homework during class.
Exam was too long and we were not provided enough time. I felt like if people started with the first part and wrote down something for each question then they would have a better chance of getting a higher score where as if you spent your time with the calculations on the second part, then you will run out of time and won’t score as well. Usually, the time it took for a GSI to finish an exam is multiply by two, and that time is what the students will get.
If I can retake this course again, I would go to office hours for each homework assignment.

Final Team Documentation

The class is finally coming to an end, and below are some last updates and detail description of our final project:

Defense:

We considered our most critical component as the defense part. For that, we stick to the original plan and build a cart that prevents opponent from driving over while having a scissoWr linkage to block the arm. We built the cart body out of aluminum plate as planned. For the cart base, instead of using 1/4" acrylic plate, we decided to go with 1/8" Hardboard, the main reason being due to material composition, it'll be harder to drill and screw on the acrylic plate, while wood board will provide same sturdiness and strength as acrylic plate.

For the boards that hold scissor linkage together, we drilled an extra hole to make the linkage 1 degree of freedom. After screwing the scissor linkages together we realized the screws come down really easily. Therefore, we used super glue to secure the plates together.




Please see pictures below for finished product:

The wiring/shaft & motor/scissor linkages & plates close up inside the cart.

Exterior of the cart body. The PVC pipe, which is used to connect to the PVC block of the arm, beside the wheel is replaced with time belt pulley to connect to the fixed motor. The rubber bands on wheels are replaced with velcro and sand paper to increase traction.

Offense: Mechanical Arm

Instead of building the pump that contract balls and transport to the other side as we proposed, we decided to go with a very simple mechanical arm design. The arm is made out of aluminum plate. The 1/4" aluminum rods, which are used to connect to the PVC block mounted to the arm, are used to screw the block on the fixed axis. The arm is mounted to a block, which is screwed to the fixed axis on the arena. There is a scoop on the arm, so it can pick up balls easily. When the arm is powered by motor, it will rotate and swing the balls to the other side. Originally, we were going to make the arm go in clockwise direction. However, after testing, we found out it is easily to swing the balls over in counterclockwise direction.

-CAD model for mechanical arm-

-CAD drawing for the mechanical arm-

See pictures below for product:





See: Final Bill of Materials

Final Reflection- Eileen Hsiao

I was very excited coming to Mechanical Engineering 250 class. I am an IOE major, but I have a true interest in designing and building things. I came in to the class with little expectations, thinking the class will be fun and easy. Looking back, I should have been more prepared for everything that I’ve done and learned. However, I did come out with many valuable lessons.

I thought the lectures were very comprehensive, but the formats of how materials were constructed seemed less applicable to what we did in the second part of class. I had a lot of difficulties with the homework and CAD assignments. I have no prior experience with SolidWork, and when we had 6 assignments, including rough drafts of milestones, to complete, it was very hard to do CAD assignments well. The work was demanding, and a suggestion is focus lab sessions on homework more. In addition, the exam was very long and difficult.

Teamwork was the hard part of the class. I thought that everyone, including myself, could’ve been more motivated in the design process and done better. A main problem is that everyone has different expectations and methods of approach for the project, thus making it hard to decide and come to a conclusion. Most of us do not have much CAD or manufacturing experiences, and it’s hard to be realistic with design. In addition, it’s also stressful to manage and organize meetings and materials to get the team to work. I especially learned to be flexible with decision makings. You cannot always expect something to be perfect, and when the situation goes wrong, you need to communicate with the team for a solution. The manufacturing was also hard. The machine shop trainings were helpful, and they were great for introducing the process, but having them scheduled so early in the semester makes the actual engineering hard. When I had to manufacture, I was very confused and frustrated with my lack of knowledge, which caused reduce in productivity because I had to constantly ask questions. Also, there are many minor details about manufacturing that I’m not very aware of, and I wished I put in more efforts learning it and refining the design.

Most importantly, I learned the importance of time management. Aside from difficulties with teamwork, the main cause is time management because of our individual scheduling. Also, we should’ve planned things ahead so we have more time to prepare for the project. Same for manufacturing, we should’ve started earlier. I was set on pushing other teammates to have same understanding of the progress, but I could’ve spent more time discussing ideas together and getting to know their thoughts on the project.

The class may need a few points of improvement in the future, but I also learned a lot from the experience. Teamwork and time management are really important components in the class, but I failed to neglect it at times. Overall, I think I could’ve done better in class and been more prepared. If there’s any other design/manufacturing opportunity in the future, I’ll be sure to apply what I’ve learned from this experience.

Kyle Boyle- Individual Reflection

Individual Reflection- Kyle Boyle

Mechanical Engineering 250 was an extremely hard class for me. I had never really done anything similar to what we did in class before. While I understood most of what was going on in lecture and it seemed interesting to me, it ended up being a lot more difficult and time consuming than I thought. That being said, the class ended up teaching me a lot in areas that I did not expect.

The lectures for me were for the most part interesting. However, a lot of the time I would either think that the material was either really simple of really complicating. It seemed like there was too much information on how to design something and not enough on how to actually manufacture it.

The homework was the hardest part of the class for me. I could see the relevance to what we are doing in the class, but I think it would have been really helpful if the homework was connected to the lectures somehow. I understand recitation was to fill that void, but it is not part of the required 4 credit class and sometimes our schedule does not allow us to attend.

An area I learned a lot about in this class is teamwork, both good and bad. I know at sometimes my team, including me, could have been a lot better. I learned that organization is key when working with a team. You have to set ahead of time who is doing what, when they are doing it, and how they are doing it.

The area I learned the most in in this class is time management. There were times throughout the class when I was really stressed out mostly because of the amount of time I had to finish it. Like I said before, I have never done this type of project before so I was in for a rude awakening. I usually assume things would take shorter than they really did which was a mistake on my part because really I had no idea. Things like drilling a simple hole or mounting a simple axis surprised me on how difficult and time consuming it really was. This is where I feel it would have been helpful in lecture to give a more descriptive detail on how the manufacturing processes were going to happen. How long, with what machines and alternatives, what could go wrong, etc. I also learned that when making your machine you had to plan on something to go wrong. Every day, it was something wrong in your plan, something you did not account for, a wrong manufacturing method, or something as simple as a machine being taken and you have nothing else to do but sit there and wait. And you were always at the mercy of the machine shop hours considering that nobody really has tools at their dorm or apartment.

While I do think some things in the class could have been improved, I do think I could have dealt with the class a lot better than I did. I feel like I could have planned ahead a lot more and went in the machine shop early so I knew what I was doing. Also, I wish that I could have made it to more of the recitations for the homework.

Design Expo

The end is finally here. We couldn't be any happier.

11-30 Week Progress Report

10 Days Countdown until Design Expo! Our team is making much progress in hopes that our machine will perform well on the competition. It's very exciting to see that our design actually comes out well and has feasible functions. So below is a few updates on the project this past week:

• We made several modifications on the cart. Last week, we spent plenty time trying to lathe the shafts due to different gear and wheel sizes. We got that working now. In addition, we also fixed our Most Critical Module, the scissor linkages, and add the release mechanism to make sure the module can successfully fall down and perform its task of blocking. Please see below for the product pictures.

• For the offense mechanism, we made a very flexible decision and decided to go with a very simple mechanical arm. It's an arm that's attached to a block that connects to the fixed axis. The arm has a rotary motion, and it picks up balls and swings them to the other side. Again, please see below for pictures.

• One of the major problems during manufacturing was figuring out lathe. We spent a lot of time threading the rod that goes into the block for the arm. We've attached a CAD copy, and that's a pretty nice representation of what we have.

• On a side note, in order to protect the arm/arena slot, as well as creating traction on the mechanical arm, we taped the arm with red wire tape. Kyle, being the big Red Wing fan that he is, is very pleased with the product. And later on, we will also logo it with superman block! ;)

Excitement ensures as the clock ticks away!

11-23 Week Progress

Everyone is getting ready to celebrate Thanksgiving this week. Milestone 7 was due on Monday. We were asked to demonstrate working Most Critical Module, and the outline of plan for the rest of manufacturing, and we made some significant progress.

First, we created the scissor linkage, which we will use for our MCM. We considered the linkage to be MCM because our machine's primary functional requirement is to block the opponent using the linkage. The plates are made out of acryllic plates. We cut out 12 plates and assembled them with screws and nuts.


Then there was the assembly of the cart. We made many connecting pieces and bearings for the base of the cart and shafts. One problem we encountered was that the sizes are different for the gears and the wheels, so mounting shaft was a big issue. Also, alignment of holes was also unexpected when we mounted the base to the cart.

Progress Report Week 11/16-22

This was a very busy week for all of us on the team. Tuesday was Tay's birthday and he had two two tests that day including the 250 Exam we all took. At least three of us also had tests on Friday as well. Even so, we still had work to do for the project being that we had three finished parts due Friday.

We chose to begin work on our MCM, the cart. This module is described in detail in the previous post. The parts we chose to make were pretty simple because they are the first ones we made, so it was a learning process for all of us. We cut the walls out of plates to the necessary size and added necessary details. Some of the things we learned were the importance of drawing correct lines and communication. Also we learned the importance of checking your work to make sure that everything is how you think it is and how the machines in the shop work and their limitations.

Then Michigan football embarrassed the U for the 6th straight year. Hooray for basketball season.

Some important images from the week:

11/2 Week Progress Report

Things Completed:
The most important task this week was to complete MS6: Most Critical Module. We successfully finished it, with a few more details to go over in the upcoming team meetings. See below for MCM details:

We did our analysis on the cart, which we will use as our defense mechanism. The reason this is our most critical module is because our strategy is more defense-oriented, and the mechanism will be more critical in determining the result.
CAD model:
This is a very simple cart design, with the usual essential gear, shaft, wheels, and cart body. The two plates in the middle of the cart is used to secure scissor linkage. We plan to mount the scissor linkage on it in a certain angle so as it falls down, it will act as a blockage for opponent.
Drawing:
Analysis was done on how much traction the cart can endure. We're counting on a higher friction on the cart so opponent can't push us over. And we also calculated the shear on the scissor linkage. This is to see how much force the linkage can take before the joints fail. Lastly, we did how much time it takes to release the linkage to the slot, and the dimensions of the linkage to determine area of blockage.

Bill of materials:


Manufacturing Step-by-step


To do list:
1. Finalize the pump design
2. Modify the bill of materials for specifications
3. Discuss manufacturing of linkage plates or purchasing them?



Next week will be a long week.

Strategy & Module description

ME 250 is a design and manufacturing class. We have to design a competitive machine that will transport ping-pong balls on an arena while defending for opponent strategy. After long deliberation, our team decides on the following strategy.

Strategy Description:
We have a pump(see below) that connects to the side of arena. The pump is connected to a gear that controls the vertical motion of the pump, and it'll be used to elevate balls and transport them over through the pipe. For defense, we have a cart with scissor linkage attached. The cart will drive over to opponent side and release linkage when game start, and this provides blockage inside the slot as well as a barricade on the arena floor to prevent opponent from coming over.

The Pump:

The pump is use to bring balls in the slot to a higher elevation and allow the balls to roll over to the opponent side of the slot.

The Cart:

The cart will be use as our main defense in the slot and on top of the arena. A scissor link that is attached to the cart will be lower into the opponent side of the slot to prevent any balls from coming over from the opponent side. The cart will be wide enough to prevent opponent cart from making an attack on top of the arena.

Team Schedule

Following is the team schedule for the next 2 months. The spreadsheet includes to-do lists, deadlines, and estimated working hours.
http://bit.ly/3nvAqi


-Team Concept