Our final bill of materials:
http://goo.gl/HHzGL
Sunday, December 12, 2010
Final Team Design
Our final machines, the Sweeper Car (right) and the Flipper Blocker (left)
Sweeper Car
This is the versatile machine that is designed to score both on the table top and in the slot. Its movement is powered by a double-gearbox, enabling it to turn by reversing the direction of one of the powered wheels.
The Sweeper Car is equipped with the sweepers and the mechanical arm module.
The yellow foam sweepers operate simultaneously, sweeping balls underneath the car as the car maneuvers on the table top. The other sweeper keep the balls in. The Sweeper Car scores on the table top by driving over the opponent's cone, dropping the balls. A six-speed gearbox with a system of pulleys and belts power the sweepers. The foam are set just at the right height so the balls could be swept in smoothly and quickly.
While over the slot, the mechanical arm can extend downward into the slot. The Sweeper car is able to push the balls in the slot while driving forward to score. The mechanical arm is powered by a planetary gearbox. It creates enough torque to lift up the whole Sweeper Car, as shown at the end of the video posted below.
Flipper Blocker
The Flipper Blocker is a gravity powered machine to block the flipper in the slotbot arena, enabling the Sweeper Car to score in the slot and preventing our opponent from scoring. The main arm of the blocker is kept up before the game starts simply with the foam sweeper of the Sweeper Car. The instant the game begins, the sweepers are turned, dropping the blocker.
A dropping of the blocker into the slot is shown in the below video at 0:44
Sweeper Car
This is the versatile machine that is designed to score both on the table top and in the slot. Its movement is powered by a double-gearbox, enabling it to turn by reversing the direction of one of the powered wheels.
The Sweeper Car is equipped with the sweepers and the mechanical arm module.
The yellow foam sweepers operate simultaneously, sweeping balls underneath the car as the car maneuvers on the table top. The other sweeper keep the balls in. The Sweeper Car scores on the table top by driving over the opponent's cone, dropping the balls. A six-speed gearbox with a system of pulleys and belts power the sweepers. The foam are set just at the right height so the balls could be swept in smoothly and quickly.
While over the slot, the mechanical arm can extend downward into the slot. The Sweeper car is able to push the balls in the slot while driving forward to score. The mechanical arm is powered by a planetary gearbox. It creates enough torque to lift up the whole Sweeper Car, as shown at the end of the video posted below.
Flipper Blocker
The Flipper Blocker is a gravity powered machine to block the flipper in the slotbot arena, enabling the Sweeper Car to score in the slot and preventing our opponent from scoring. The main arm of the blocker is kept up before the game starts simply with the foam sweeper of the Sweeper Car. The instant the game begins, the sweepers are turned, dropping the blocker.
A dropping of the blocker into the slot is shown in the below video at 0:44
Reflection by Steve Hwang
Design and Manufacturing
ME 250 is to me a valuable introduction of fundamental manufacturing and machining techniques. I did not really have any experience in machining prior to this class; although I did the basic Wilson center training and participated in a design project for Engineering 100, the experience could not compare to that of ME 250. It is difficult for me to explain all that I’ve learned because I’ve essentially started out with nothing. I’ve learned the proper way to use the mill and the lathe, and I’ve also learned how to engage in an effective and systematic design process. This class as enabled our team to design and manufacture a machine with the complexity we did not expect at the beginning of our project.
Teamwork and Time management
I felt that it had been difficult for our team to find time to meet up because of our busy schedules. It’s been especially hard for me this semester, since I’m taking full credits and classes are unfortunately very spread out. Having said that, this situation made us very efficient when working together, and I’ve learned to trust and rely on my team members when I cannot show up to the meetings.
I am very grateful to my teammates because, as the one who’s the least experienced and skilled, I have learned a lot from them in many aspects. I am especially grateful to John, who had the patience to give a beginner like me detailed instructions on milling and turning when he could’ve done the parts in no time.
Overall, teamwork time management was great. We all did the best with our time. While it was inconvenient that most of our team members live off-campus and we thus could not work together whenever we wanted to, each of us were able to effectively use our strengths and our team has thus been able to stay on schedule and finish in time.
How the class could’ve improved
Although lectures included a diverse spectrum of information on gears, springs, and other mechanical components that are indeed very useful for the project and our training as mechanical engineers, many students like me whom had little prior knowledge of the material taught in lecture felt a little thrown off by the sheer amount of information that were handed to us in each lecture. I felt that students might be able to better digest the material in lecture if the lectures were made shorter. A good approach might be to assign slides for students to read prior to lecture, then quickly go through key material during the lecture and then have some time for activities and questions.
The fact that the double gearbox was not powerful enough was a frustration, as we discovered our whole module underperformed because of it. One improvement I would suggests is to either choose a more powerful gearbox set or give students ways to know whether the gearboxes are able to support their system. For instance, past examples of weight vs. speed performance of different teams’ machines could have been given to us as references.
At last, the trainings during the first few weeks of class were not very helpful. By the time we needed to machine, lots of students have already forgotten how to use the equipments. The trainings should be moved closer to the time of machining. I also suggest instructional videos on the mill and lathe to be made and put online for students. There is really no way to remember everything just from the hour long training sessions in the shop.
How I could have improved
I should have taken fewer credits during this term. I took 18 credits and classes are very spread out. A 14 to 15 credit hour should allow for better time slots for machining outside of class time.
There are numerous other things I should’ve considered and improvements I could have made. The most important is probably paying attention to detail that are not listed in requirements. Many questions involving calculations in this class are quite open ended, and I’ve found myself missing out important things because I were not careful enough to consider those questions in realistic settings. This is certainly an important improvement I need to make to become a successful engineer.
Reflection - Peter Turpel
After taking ME250 I’ve developed a stronger appreciation for people involved in the design and manufacturing process of even everyday objects. The level of foresight needed became apparent during our project when glitches would pop up and force us to adapt our design. For example: not adequately factoring in the space needed for bolt heads and the extra material in the corner of an angle bracket, or the difficulty assembling parts with fasteners in restricted areas. Additionally, getting to build the parts ourselves in the machine shop was probably the best way to impart the importance of making good engineering drawings, as well as giving us an idea of the capabilities/limitations of the machining equipment. Despite the sometimes aggravating on-the-job-training, the design and manufacturing component was the most fun part of this class. Being given guidelines and a goal to work towards (the competition) and then being allowed to design and build on our own was definitely preferable to just reading a book or getting lectured about the design process.
The team aspect of the course was a good way to see people’s different methods of problem solving. Even before we formed teams, the peer review process on the early milestones showed me the huge range of ideas people came up with to play the game, most of them in ways I never would have thought of. After getting in our teams we were able to combine our individual ideas into concepts that were much more capable than anyone’s alone. We also ran into some challenges, though, as it was often difficult for our team to get together because of our varied schedules. This was especially bad when it came to the labs and GSI meetings that were performed outside of normal class time. When it came time to begin machining our parts this also meant that we were often working alone, and a heavy load fell on the more experienced members because those without prior machining experience weren’t able to get as much done by themselves. However, I feel that everyone contributed as best as they could in the areas that they were strong.
One thing I think could improve the course would be to spend less time on the individual milestones in the beginning of the class. The strategy and concept portions could be condensed so that students form into teams sooner, potentially allowing for more build time. Also, the bike lab didn’t feel like it had a direct benefit towards this class, and it might have been nice to have done the motor lab sooner to get a chance to explore the capabilities of the motors. I know my teammates have mentioned the disappointing performance of the dual gearbox, so I won’t beat a dead horse other than to say that I can understand that trying to make do with low power motors might be more effective for learning than giving us more than we need, but it was still frustrating. It seems like the slotbots game was more complex than the last time, but the resources in materials and time didn’t keep pace with that increase. A lot of teams set their sights high for their bots, but weren’t able to realize their visions.
One thing that I think could have helped me in this class is if I had been able to get more time and practice on some of the equipment. Some things in the shop I never got a chance to see used, like the laser cutter. Another thing I’ll try to take to my future classes is the importance of designing and building in smaller steps and getting to testing sooner. For example, our MCM had a lot of parts that had to come together before we could do try it out. By the time we got our car powered up and saw the limitations of its performance, it was too late to redesign with different motors or gearing.
Reflection on ME250 -Joseph Goetz
ME 250 gave me valuable exposure to various fundamental manufacturing and machining techniques. Though I have often tinkered on small mechanical projects before, this initial design and manufacturing course has allowed me to operate various core manufacturing machines including mills, and lathes. Not only has the experience made me a fundamentally competent operator of these machines, more importantly it gave me the opportunity to more fully understand the abilities and limits of these manufacturing machines. For a brief example, I learned that to machine an approximately 20” slot in a 1”x1” aluminum tube which our design called for, the only proper way to do that is to use two vices on the mill table, using one at each end to secure the part. Overall, my involvement in the manufacturing of a slotbot gave me a valuable foundation to learn from in my engineering career.
Most of the lessons learned about designing came after manufacturing and assembly were well under way. The complete design and manufacturing process gave me valuable lessons and experiences on how to tolerance designs and how to make designs easier to execute. For example, when making small parts that contain fastening holes or slots, make sure that the LMC leaves adequate material to maintain design integrity. Using my experience, it is clear that an easy way to overcome that hazard would be to leave only a positive tolerance on the part’s overall dimension. Having to create a manageable yet complex machine gave me invaluable and even some intangible engineering experiences and an enlightened understanding of designing and engineering.
Team work was an important aspect of ME 250. The nearly complete integration of team work into the course taught me that I must rely on my teammates. To best accomplish the required tasks, the team should play to the strengths of each team member, whether skewing the entire tasks towards the teams cumulative spectrum of strengths, to delegating tasks that best suit each team member. The team experience also reinforced the importance of clear and concise communication and planning between the team members. Since team work is an integral part of modern engineering the team experience in ME 250 was a valuable experience to better prepare me for a mechanical engineering career.
Though the ME 250 course as a whole was helpful and informative, there are areas where it could be improved. At the beginning of the course several weeks were used for the “creative process”, however, now, in retrospect, those several weeks could have been better utilized by focusing on the spectrum of mechanism that allow those “ideas” become reality. There might be a benefit from spending some tome on the creative process; however it can be abbreviated from its current time allotment in the course schedule. That extra week or two would then be of great benefit to the team portion of the course, allowing the work load of that section of the course to better correlate to the progression in the course timeline. Then a final frustration with the course would be the dual motor gear box. Its performance was a deflating disappointment for my team, and evident in other groups’ performances, the class as a whole. My team’s design had heavily relied on its speculated robust nature, and then in the last week, when assembly was in full swing it became evident that it was going to underperform, but at that point there was no time for recourse. Now as my team was finishing the final bill of materials, and tabulating a complete cost of the bot, the inferiority of the double gearbox can be easily seen when it was noted that the double gear box cost approximately half that of the other two motors, and two motors and gearboxes are included in the price. Despite this last minute disappointment, overall, the ME250 course was very helpful and educational.
Most of the lessons learned about designing came after manufacturing and assembly were well under way. The complete design and manufacturing process gave me valuable lessons and experiences on how to tolerance designs and how to make designs easier to execute. For example, when making small parts that contain fastening holes or slots, make sure that the LMC leaves adequate material to maintain design integrity. Using my experience, it is clear that an easy way to overcome that hazard would be to leave only a positive tolerance on the part’s overall dimension. Having to create a manageable yet complex machine gave me invaluable and even some intangible engineering experiences and an enlightened understanding of designing and engineering.
Team work was an important aspect of ME 250. The nearly complete integration of team work into the course taught me that I must rely on my teammates. To best accomplish the required tasks, the team should play to the strengths of each team member, whether skewing the entire tasks towards the teams cumulative spectrum of strengths, to delegating tasks that best suit each team member. The team experience also reinforced the importance of clear and concise communication and planning between the team members. Since team work is an integral part of modern engineering the team experience in ME 250 was a valuable experience to better prepare me for a mechanical engineering career.
Though the ME 250 course as a whole was helpful and informative, there are areas where it could be improved. At the beginning of the course several weeks were used for the “creative process”, however, now, in retrospect, those several weeks could have been better utilized by focusing on the spectrum of mechanism that allow those “ideas” become reality. There might be a benefit from spending some tome on the creative process; however it can be abbreviated from its current time allotment in the course schedule. That extra week or two would then be of great benefit to the team portion of the course, allowing the work load of that section of the course to better correlate to the progression in the course timeline. Then a final frustration with the course would be the dual motor gear box. Its performance was a deflating disappointment for my team, and evident in other groups’ performances, the class as a whole. My team’s design had heavily relied on its speculated robust nature, and then in the last week, when assembly was in full swing it became evident that it was going to underperform, but at that point there was no time for recourse. Now as my team was finishing the final bill of materials, and tabulating a complete cost of the bot, the inferiority of the double gearbox can be easily seen when it was noted that the double gear box cost approximately half that of the other two motors, and two motors and gearboxes are included in the price. Despite this last minute disappointment, overall, the ME250 course was very helpful and educational.
Friday, December 10, 2010
Reflection By Jonathan Peabody
Design and Manufacturing:
This class has been an outstanding refresher for the material that I already knew, and a great supplement for the material that I did not know. I only understood basic machining principals, the ideas behind alignment of shafts and supports, couplings, fabrication and assembly strategy. First and foremost, I did not have any knowledge of the solidworks program. My section leader Mark Gordon is an outstanding GSI who showed great competence and patience while handing us the foundation and basic principals of the program as beginners. Our team spent endless hours drafting our slot-bot, and found that the prints we generated allowed us to produce the project that we intended on having, nearly to perfection. The program aided us with critical dimensioning for machining that we wouldn’t have been able to produce by hand, under the scheduling guidelines. The only errors we struggled with were those in our engineering.
Furthermore, I learned how several types of levers, gears and springs were designed, along with a diverse explanation on dynamic inputs and output responses and applications for special situations. Although our team didn’t use many of the different mechanical concepts that we were shown, we did think about them. The lectures helped open up some of the creative options that were available and I noticed many of the applications shown in class being used on other teams’ slot-bots. I learned almost as much from looking at others’ slot-bots, as I did ours.
Teamwork and Time Management:
We had a hard time pulling things together at some points due to our class schedule. Each of us had a full schedule and it made it tough to plan things outside of normal class meeting times. Typically when we did meet, say, on Friday nights for instance, we would spend 6-8 hours together trying to cram in as much engineering as possible because we didn’t know when we were going to be able to meet again. We were able to stay on task, and remain focused on the goal of the project. Our wasted time was minimal. I feel that some of the machining fell a little heavy on me, but the others tried to make up for it the best that they could, and often asked if there was any way they could help. Just the thought of them asking, made up for the fact that there wasn’t much else they could do. Because I had more experience in machining, things just worked out that way due to the time constraints. As a whole, I feel the weight of the project was distributed as evenly as it was ever going to get. Each of us showed the strengths in the areas that we were strong in, and did the best with what little time we had. Communication flowed great, and I think each of us adapted to our workloads well.
Class critique:
How the class can be improved:
Many of the classmates, including myself, felt that there was far too much emphasis on the creativity portion early in the term. On a whole, myself (and others) felt that the creativity was a good thing, but there was enough of a diverse spectrum within Mike Umbriac’s lectures on levers gears and springs etc. to make the significant contribution to open minded development of the project. He did a great job in expanding our minds to new ways of thinking and different ways to look at things. However, once his lectures rolled over into engineering and machine time, I felt like we were constantly behind. Perhaps a good switch for early creativity emphasis might be to schedule the motor lab early in the term. This would possibly help to bring scope of motors’ potential into the engineering and design areas. Due to the fact that the motor lab occurred so late in the term, I heard some students mention that their engineering was completed before they had the chance to see what the motors could do.
I was definitely surprised at how slowly the car moved with the double gearbox motors. If there were one improvement I could have made, it would have been to make those two motors stronger, or upgrade to a more powerful gearbox/motor setup all together. I feel that we would have won the competition had we not suffered in the tabletop play due to motor weakness. It was a bit unfortunate after 16 weeks to see the car unable to negotiate the white strips of delrin, with our mass. We were asked to calculate gear ratio based on feet/second and as it turned out, the small motors were too loaded to achieve our goal with proper ratios. We over-estimated their potential.
I feel the bike lab was not needed. We covered many of the principals of this lab in class. Mike walked us through some calculations in preparation for it. Perhaps some practice of these calculations would work out well for a homework assignment instead.
I think there needs to be much more emphasis on machining process and tact. Mike’s blueprint section was outstanding and very helpful not only to this project but to our future. But beyond that, I noticed there was very little classroom time spent on machine setup and process. There was no way for Bob Coury to teach 100+ students proper and safe tact to machine parts. He was so busy, people sometimes didn’t have time to ask him what to do, and they tried doing it themselves, sometimes doing things wrong and getting caught. Although he offered his help as much as he felt he had time to, many of us saw him lose patience on several occasions and simply threaten to throw students out of the shop for what he considered improper method without a first warning, or even first address. In retrospect, I feel he was simply overwhelmed with the responsibility of trying to make sure students do things correctly and this burden (due to the number of students) pushed him to his limits of reasoning. If there were classroom time that announced basic patterns of logic (i.e. how to correctly secure parts in the vice, or how to machine in stages such as the machining process asked for on the exam) then Bob would have some background on the student to ask them about; Bob could ask, “How were you shown in class, does your way seem reasonable according to what you were taught?” Without this foundation, he was left to teach proper or safe tact himself, to a seemingly endless number of eager-to-learn students. In my opinion, it is far too much for one man to handle in that short time frame. I might have lost patience too had I been in his shoes.
How I could have improved
I took too many classes this term. I feel that the content of this course is strong enough that students who have more than 12-14 credits (as I have 16 credits) should be aware of the time commitment that is needed to be thorough in designing engineering, and manufacturing processes. Although I never lost focus on the project, I found it difficult to maintain a schedule and still remain in good standing in other classes. My grades have suffered in one class in particular due to the demand of ME250. I am now taking huge strides to catch back up.
There are many other improvements that I could have made. Each point that I have lost on assignments is an improvement that I feel responsible to make upon myself. (If I explained all of my shortcomings, this reflection would go on forever!) I am nowhere even close to perfect, and have found this class to be a tremendous learning experience. The extreme detail that was covered for us is untouchable. Professor Hart, you have an OUTSTANDING foundation in this material, and are definitely the right person for this job. I thank you greatly for sharing your knowledge and experience and all that your team has showed and taught me. I found this class to be very valuable in my education as a Mechanical Engineer. Mark Gordon is an outstanding GSI. I thank him for his extra effort in this class as well. Mike Umbriac and Toby are also outstanding members of your team; I appreciate all that you guys have done for this program.
This class has been an outstanding refresher for the material that I already knew, and a great supplement for the material that I did not know. I only understood basic machining principals, the ideas behind alignment of shafts and supports, couplings, fabrication and assembly strategy. First and foremost, I did not have any knowledge of the solidworks program. My section leader Mark Gordon is an outstanding GSI who showed great competence and patience while handing us the foundation and basic principals of the program as beginners. Our team spent endless hours drafting our slot-bot, and found that the prints we generated allowed us to produce the project that we intended on having, nearly to perfection. The program aided us with critical dimensioning for machining that we wouldn’t have been able to produce by hand, under the scheduling guidelines. The only errors we struggled with were those in our engineering.
Furthermore, I learned how several types of levers, gears and springs were designed, along with a diverse explanation on dynamic inputs and output responses and applications for special situations. Although our team didn’t use many of the different mechanical concepts that we were shown, we did think about them. The lectures helped open up some of the creative options that were available and I noticed many of the applications shown in class being used on other teams’ slot-bots. I learned almost as much from looking at others’ slot-bots, as I did ours.
Teamwork and Time Management:
We had a hard time pulling things together at some points due to our class schedule. Each of us had a full schedule and it made it tough to plan things outside of normal class meeting times. Typically when we did meet, say, on Friday nights for instance, we would spend 6-8 hours together trying to cram in as much engineering as possible because we didn’t know when we were going to be able to meet again. We were able to stay on task, and remain focused on the goal of the project. Our wasted time was minimal. I feel that some of the machining fell a little heavy on me, but the others tried to make up for it the best that they could, and often asked if there was any way they could help. Just the thought of them asking, made up for the fact that there wasn’t much else they could do. Because I had more experience in machining, things just worked out that way due to the time constraints. As a whole, I feel the weight of the project was distributed as evenly as it was ever going to get. Each of us showed the strengths in the areas that we were strong in, and did the best with what little time we had. Communication flowed great, and I think each of us adapted to our workloads well.
Class critique:
How the class can be improved:
Many of the classmates, including myself, felt that there was far too much emphasis on the creativity portion early in the term. On a whole, myself (and others) felt that the creativity was a good thing, but there was enough of a diverse spectrum within Mike Umbriac’s lectures on levers gears and springs etc. to make the significant contribution to open minded development of the project. He did a great job in expanding our minds to new ways of thinking and different ways to look at things. However, once his lectures rolled over into engineering and machine time, I felt like we were constantly behind. Perhaps a good switch for early creativity emphasis might be to schedule the motor lab early in the term. This would possibly help to bring scope of motors’ potential into the engineering and design areas. Due to the fact that the motor lab occurred so late in the term, I heard some students mention that their engineering was completed before they had the chance to see what the motors could do.
I was definitely surprised at how slowly the car moved with the double gearbox motors. If there were one improvement I could have made, it would have been to make those two motors stronger, or upgrade to a more powerful gearbox/motor setup all together. I feel that we would have won the competition had we not suffered in the tabletop play due to motor weakness. It was a bit unfortunate after 16 weeks to see the car unable to negotiate the white strips of delrin, with our mass. We were asked to calculate gear ratio based on feet/second and as it turned out, the small motors were too loaded to achieve our goal with proper ratios. We over-estimated their potential.
I feel the bike lab was not needed. We covered many of the principals of this lab in class. Mike walked us through some calculations in preparation for it. Perhaps some practice of these calculations would work out well for a homework assignment instead.
I think there needs to be much more emphasis on machining process and tact. Mike’s blueprint section was outstanding and very helpful not only to this project but to our future. But beyond that, I noticed there was very little classroom time spent on machine setup and process. There was no way for Bob Coury to teach 100+ students proper and safe tact to machine parts. He was so busy, people sometimes didn’t have time to ask him what to do, and they tried doing it themselves, sometimes doing things wrong and getting caught. Although he offered his help as much as he felt he had time to, many of us saw him lose patience on several occasions and simply threaten to throw students out of the shop for what he considered improper method without a first warning, or even first address. In retrospect, I feel he was simply overwhelmed with the responsibility of trying to make sure students do things correctly and this burden (due to the number of students) pushed him to his limits of reasoning. If there were classroom time that announced basic patterns of logic (i.e. how to correctly secure parts in the vice, or how to machine in stages such as the machining process asked for on the exam) then Bob would have some background on the student to ask them about; Bob could ask, “How were you shown in class, does your way seem reasonable according to what you were taught?” Without this foundation, he was left to teach proper or safe tact himself, to a seemingly endless number of eager-to-learn students. In my opinion, it is far too much for one man to handle in that short time frame. I might have lost patience too had I been in his shoes.
How I could have improved
I took too many classes this term. I feel that the content of this course is strong enough that students who have more than 12-14 credits (as I have 16 credits) should be aware of the time commitment that is needed to be thorough in designing engineering, and manufacturing processes. Although I never lost focus on the project, I found it difficult to maintain a schedule and still remain in good standing in other classes. My grades have suffered in one class in particular due to the demand of ME250. I am now taking huge strides to catch back up.
There are many other improvements that I could have made. Each point that I have lost on assignments is an improvement that I feel responsible to make upon myself. (If I explained all of my shortcomings, this reflection would go on forever!) I am nowhere even close to perfect, and have found this class to be a tremendous learning experience. The extreme detail that was covered for us is untouchable. Professor Hart, you have an OUTSTANDING foundation in this material, and are definitely the right person for this job. I thank you greatly for sharing your knowledge and experience and all that your team has showed and taught me. I found this class to be very valuable in my education as a Mechanical Engineer. Mark Gordon is an outstanding GSI. I thank him for his extra effort in this class as well. Mike Umbriac and Toby are also outstanding members of your team; I appreciate all that you guys have done for this program.
Tuesday, December 7, 2010
Sunday, December 5, 2010
Almost There
The past week wasn't as productive as we'd hoped due to the scarcity of time slots on the mill. However, our car assembly is finished including the main car module, the sweeper system, and the mechanical arm. If we can get some time on the mill Monday we should be able to finish our flipper blocker, which was proposed as a "time permitting" module anyways. We can also devote a lot more time to driver's training now, which is going to be key to our machine not getting stuck in the slot or funnels.
John milling the first part of our flipper blocker
Testing our extending arm
The arm raised in the starting position
Extended fully into the slot
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