Devin Hotchkiss reflection

This class has taught me a lot about the start to finish process of creating a functioning machine.  Conceptualization, design, fabrication, redesign, and final assembly all were key steps we took throughout the semester to make a competitive robot.  Having a background on the SAE Baja team, I was somewhat familiar with machining techniques and CAD modeling.  However, this course allowed me to look at a system with different constraints and on a smaller scale than I was used to.  In addition, using Solidworks expanded my repertoire of CAD packages and helped me recognize some of the differences between softwares.  Learning how to use the laser cutter and the waterjet machines was also a new experience that I enjoyed.

One of the biggest lessons I will take from this class is that the design process is all about iteration.  After modeling and fabricating a part, it is often the case where upon re-evaluating the functionality of the piece, a better solution or design may be discovered.  It is important to then redesign the piece for reasons such as easier manufacturability or ease of assembly.  Looking back at the blog, it is clear that some of the components on our machine evolved from the original concept.  On that note, one of the biggest factors weighing into redesign of parts – and our machine in general – became simplicity in both machining process and integration into the final assembly.  Nothing beats having a simple, reliable design that accomplishes one task very well, as opposed to trying to do to many different things with a decent level of success.

Another important lesson I will take away is the value of working in small groups.  Being able to communicate with everybody working on the project and keeping them up to speed with the robots progress was key to our success as a team.  Weekly team meetings were helpful in making sure everyone knew what was going on and what tasks or parts still needed to be completed.  Having a schedule or at least a rough timeline to keep us moving forward with our project beneficial.  I felt that the class assignments and milestones did a fairly good job of outlining the process for us even though objectives tended to ramp up quite a bit at the end.

Overall, I thought the course was well constructed and covered a broad range of useful material for design and manufacturing.  The lectures covered a lot about different machine components, like bearings and power transmission as well as many design theories.  However, I thought it might be useful to include a lecture (or part of one) on different tips and tricks of the actual machining.  Processes such as zeroing a piece from the middle, or how to ensure the piece is squared up (all right angles) might have been useful to know about and discuss in lecture that way our time in the machine shop would be used more effectively.

I could have improved my performance in the course by learning how to delegate better and doing a better job sharing my previous knowledge of machining with the rest of my teammates.

Erik Zillner Reflection

Before coming into this class I only had a very general idea about the concepts of design and manufacturing. I had only been exposed to what I see on TV and had never had a chance to dive deeper into what it takes to create and build a custom idea. The whole process is a much more difficult and tedious than I had ever imagined. But looking back on the course I now realize why all work must be very diligent throughout the entire process. A slip-up early on in the process would lead to many troubles down the road so I now know why it is extremely important to precede each step with a lot of caution. I never really understood the point of tolerances before we began our manufacturing process. I didn’t realize that there were a lot of little imperfections that could lead to errors later in the building phase (dull drill bit, error while measuring, etc.). I also learned the importance of having accurate CAD models. This is something that I had not been exposed to previously. A CAD model is the building block of the manufacturing process, which is why everything must be perfect with it. But even a perfect CAD model can’t predict future problems, as I found out. After manufacturing all of the parts and assembling our machine, we found out that some parts didn’t mesh together as nicely as we had thought or bolts were interfering with each other. This was a key learning experience for me. When a design is still in the works, it is important to consider every little detail from the length of a bolt to the size of the nut you want to use. Overall this was a very nice learning experience in a setting where we were allowed to make mistakes and then learn from them.

This course also taught me a lot about teamwork and time management. If there’s one thing that I took away from this, it was about using time efficiently while we were all together. In a school setting where everyone is busy with their own schedules, I found that it was very important to use our time as efficiently as possible when we were all able to meet together.

Overall I thought the course went very well, but I had some problems with it as well. I found that it was very difficult to find machine times during the manufacturing stage because I felt like we had such a short time to build our machine. We spent about 13 weeks designing and then about 3 weeks building and with all of the classes using one machine shop, it got frustrating when we couldn’t find time for the machine we needed. I realize designing is the most important part of the overall process but I think it would have been helpful to design and manufacture little bits at a time.

I could have improved my performance by learning the ins and outs of the CAD program a little better. I sometimes felt that my inadequacies with the CAD program would limit my ability to help with the overall design. It’s something I can look to improve in my later years here at the university.

At the end of the day, I can say that I took a lot away from this class- something I can’t say for most classes- and what I’ve learned in this class will carry me through the rest of my time here and throughout my career.

Sam Kapor Final Reflection (of the Process)

ME 250 proved to be both a very challenging and rewarding experience especially with respect teamwork, design, and manufacturing. During the first half of the class, through lectures and labs, we learned a great deal about the fundamentals of the design and manufacturing process on both a large scale and a small scale. We learned that you first stat with a problem for which you compose a strategy or a general approach to a problem. Then you come up with a concept or a specific vision of how your strategy is achieved. Next you come up with a module and a sub-assembly that has a defined envelope and specific inputs and outputs. You can then break it up into components, individual parts such as gears beams, or springs. Designing itself is defined by a series of steps that brings you from a course point to a fine point. You must explore, experiment, create, detail, then build and test. During this one first takes stock of the available resources. Then one studies and tires to understand the problem they are solving. Then one comes up with possible strategies for solving the problem. This is followed by concepts for implementing the strategy that is fond to be the best or most effective. Once this is done, you begin to develop models and the components that would be used. This also requires detailed engineering designs and detailed drawings, which can be made using software such as Solid Works (as we did for our machine). Once this is completed you can then begin to build, test, and modify your machine or concept while referring back to the drawings and designs you created. For example, after we finished designing our machine on solid works we found that as we began to actually machine our parts, we needed to deviate from our design and make modification. Once we finished building and assembling our machine and stared testing it we also found that we need to make additions to it. While testing our machine on the ground, we found that experienced a great deal of slipping. First we tried adding different treads to it, but this still did not solve the problem. We also tried rubber bands and glue. After this failed we made one last attempt through the use of duct tape. This proved to be a great success. We were not only able to maintain a relatively fast speed, but we were also able to maintain enough friction with the ground allowing us to climb up part of the wave field. In addition, as we learned and practiced, you can use machines such as mills or lathes to actually make the parts for your machine or concept. One can also use different machines to make rapid prototypes before building on a large scale. One you have completed your design and finished building and testing it, you can then deploy and document or publish your design.

While it was stressed at the beginning of class and we were all warned, the greatest challenge of all is time management. At first the pace of the class seems easy and reasonable. However towards the end you are left with one week to essentially make your machine, or at least that’s how it feels. Looking back on it, the all nighters and 5 hour machining times, although unavoidable, could have been shortened if we had worked ahead early on instead of fallowing the class schedule. However, the competition, even if you don’t win, and seeing your machine actually run, does help make you appreciate all the hard work you have put into over the semester.

My performance in this course could also have used some improvement. I feel that if I had gone in for extra help with CAD, I would have been able to better assist my teammates and help prevent all nighters spent on CAD. I also think that spending more time early on and trying to get ahead in the class would have also proved beneficial and prevented cramming at the end of the semester.

While this class was definitely a fun and rewarding experience, there are still a few things it could improve in. I would suggest incorporate smaller manufacturing deadlines throughout the semester, but incorporated earlier into the schedule. I would also suggest making participation worth something towards the grade, maybe extra credit. I would also have more CAD classes or labs. Coming into the class I had essentially zero CAD experience, this I believe put a burden on the team members who had experience, and also lead to all nighters. I also think it might be worthwhile shortening the lecture a little bit putting the extra time into extending the length of the labs. I would also recommend later class time, the students will not only show up more, but will also be more inter active and focused in the class.

Post Competition

Unfortunately, we are no longer 'Still In The Process'. Going into the competition we were ranked #6. We received a pass and were automatically placed into the second round. We went up against the "Tank". In the previous round the Tank had moved the entire ball tower towards its own goal, however it did not manage to score all of the balls inside the ball tower. During our round the Tank did manage to score almost all of the balls from the ball tower. When the match initially started we were able to score a couple of ping-pong balls from the tower and place them into our own goal. However, by the time we scored the Tank had moved the tower close enough to its own goal, such that we could not get in front of it and stop it. With that in mind, we decided to go after the the squash balls on the wave field. We were able to score two black ones. Unfortunately this was still not enough and we were eliminated from the competition. We managed to design, build, and test a machine that was relatively quick, maneuverable, and dependable. Unlike many of the other machines at the competition, our machine never had electrical, control, or physical problems during the competition. Nonetheless the process, which is now over, was still a challenging and interesting one.

Phil Batterson Final Reflection

This semester in ME 250 taught me many things about design, manufacturing, and teamwork. During the first part of the class we got a deep understanding of the design process and how to implement it. To start you think of ideas, no matter how quirky every idea is okay. Then you have to narrow down those ideas into plausible ones that can achieve what the design team thinks is the most critical thing the design should be able to do. Concept sketching ensues normally with solid models to get an idea of what the final product may look like. When this is accomplished the team starts putting the ideas into a computer aided design program to be able to get solid dimensions and parts to get ready for manufacturing. After a three dimensional model is made the individual parts are made into manufacturing sheets. These give all of the dimensions necessary to manufacture the whole part. Using the mill, the lathe, a laser cutter, water jet or any other tools in the shop the parts are made and gradually assembled the machine. Once all of the parts are made and you can start using whatever you created there is a lot of troubleshooting that has to be undertaken. Parts are hard to make exactly to specification so sometimes they do not fit the way you want them so there needs to be some tweaks made, edges sanded down, etc. Once everything is put together its time to test the design to make sure it works the way you want it to if it does not then its back to the tweaking stage of design. For example our team had everything assembled but the treads were slipping so we had to add adhesive to them, which came in the form of duct tape.

Throughout this process one huge barrier to accomplishing getting our vehicle finished was time. I know for myself I did not put aside enough time throughout the process so I would scramble towards the end of a due date to get things finished. Like pulling all nighters in order to get the entire CAD model, and the manufacturing done at the end of the semester. The design process is a large time commitment but when you have a finished product ready for the ball competition or whatever you want your final achievement to be the time investment is all worth it.

In order to better my performance in this class I think that if I had devoted more time in the beginning of the process rather than cramming it all in at once would have significantly helped me. Given that I think our team still was able to make a good robot and accomplish our strategy during the competition even though we lost in the first round to a team we could not defended against.

Overall this course was exceptional. I enjoyed most aspects of it. A few things could be improved upon though. The first is that I do not think CAD was taught in depth enough coming into this course I had four years of CAD classes so I knew how to use it well but the kids that had no background in CAD really struggled to understand some concepts. The second is that going to class should have been worth some amount of points to our grade, I know it was reflected somewhat in the exam but if attendance was 5 percent of the grade then more people would benefit from lectures which were very helpful. The final thing that could be improved is that there could be a bit more feedback from the instructors about designs and what could be done to improve a design or make the machine so it does not break during the competition.

Final Design

Our final design is pictured below, as you can see from the beginning solid model we did not deviate much from our original ideas to our final product. one thing we did change was how we opened and closed the flap of the machine instead of using an arm attached to the flap we used bevel gears directly connected to the flap and the motor. This worked to our advantage because we did not have to deal with long moment arms creating large torques on the motor.

The final design started with aluminum tubing that was cut into four pieces two sides and two cross members to attach the sides too these were all made using the mill. To secure all of these members together we used right angle brackets with nuts and bolts which made it easy to assemble. On top of the frame was an acrylic plate which we cut using the laser cutter. This allowed us to mount the motors and control box on top of our machine. We also had a tread system on our robot this was given to us by a sponsor who was a teacher of one of the members of our team. all of the Vex components had square axels so we used that and drilled holes into our .25 inch axel rod that fit into all of the bushings. in order to secure the square axel to the round axel we drilled pin holes through both and put welding rod through the holes to secure them. The final component of our machine was the flap which was our MCM. We mounted this and opened it with bevel gears attached to the polulu motor which had very high torque and would allow us to keep balls in our machine.

This is the link to our final bill of materials and total costs. http://goo.gl/zxDSd

ME 250 Video

Before:

After:

Still in the process is just about done with the process. This week we wrapped up assembling our model and attaching our motors. As you can see from the pictures included we have gone from a foam prototype to an almost complete machined body.