Project Kronos team members (l-r) John Morris, Thomas Cisneros, Steven Jimenez, Paul Katsumura, Ian van den Bosch, Felipe Ortiz, Mark Hirami, Michael Frausto and Roman Kuchma.
Gears? Check. Pendulum? Check. Counterweights? Double-check.
After team runs like clockwork, a Q&A with its captain
Design it. Craft its pieces. Assemble it. Test it. Refine it. Present it. Accept grand prize for “Kronos.”
This was not their grandfathers’ grandfather clock. It was theirs, the members of the 2010 WESTEC Manufacturing Challenge Grand Prize-winning team from Cal State L.A.
They combined generations-old clock-making techniques with – and it’s literal this time – cutting-edge technology. To set their project – called “Kronos” – apart from the competition, they used “lean” manufacturing processes.
For the main Spotlight feature on the “Project Kronos,” go to http://www.calstatela.edu/univ/ppa/spotlight/archive/2010/westec-2010.php.
“We had to make sure that we did not over-engineer a concept and that the project was feasible to manufacture within our skill sets,” said Ian van den Bosch, the 10-member team’s captain. In a Q-and-A, van den Bosch offered these insights:
Sometimes a clock needs more than two hands.
Q1: How many individual pieces are involved in the clock?
A: More than 79 parts were created for the clock; and then we made two walls of wood and sheetrock/drywall for our presentation.
Q2: What’s the most critical element?
A: There are three major critical elements of a grandfather clock.
1. First is developing accurate gear ratios. Gear ratios determine how many times a gear must rotate in order for the clock to display accurate time. In our case, if one gear had the wrong number of teeth then the entire function of the clock would be inaccurate. John Morris, our mechanical engineering student, used calculus formulas to determine our gear ratios for our particular clock design.
2. Second is developing the pendulum and escapement mechanism. The pendulum swings from left to right which engages a escapement gear. The escapement mechanism drives the movement of each gear to display the movement of the minute and hour hands. The pendulum and escapement mechanism create the “tick-tock” sound you hear in most mechanical movement clocks.
3. The third critical element is designing the appropriate counter weights, which sit on either side of the clock. Counter weights do two major functions of our clock:
The weights determine the cycle of time for how long the clock will work. This is known as reset time. For example, there are clocks known as 100-day clocks or 30-day clocks, named for how often the clock needs to be reset or wound. Our clock has a 20-hour reset time; with improvements we could likely get it to a three-day reset time.
The weights also serve to overcome the inertia (resistance) of the gear system within the clock. They had to be heavy enough to create torque (twisting force) to turn a drum shaft that then turned each gear to display the movement of the minute and hour hands. Our counterweights weighed approximately 30 pounds each. With further improvements we could make the weights lighter if need be.
John Morris and other team members discuss the center of gravity of a mock-up of the clock’s back plate.
Q3: What was the biggest manufacturing challenge...and how did you overcome it?
A: Our biggest manufacturing challenge was cutting out gears using a computer-numerical-controlled (CNC) milling machine. Each gear was made of brass, had a specific thickness, and a specific number of teeth. The teeth of each gear were uni-directional, which means they only rotate in one direction. The tolerances to cut these gears was +/- .003 of an inch, a very tight tolerance. Thus, each gear had to be precisely cut to specification, otherwise the clock would not work when assembled. Thanks to our two CNC operators – Mark Hirami and Thomas Cisneros, who have had lots of hours working with CNC milling machines – the gears were precisely cut to specification. Mark and Thomas developed a fixture that held the metal that was to be cut into gears; and they accurately ran the cutting program.
We made several gears and tested that they all worked simultaneously during a pre-assembly. The idea was that if each gear meshed well together and turned one another, the gears were accurate; but we wouldn’t know truly if all the gears would work until we did a full mockup of the clock. After mocking up the clock with all the gears mounted together, we learned that one gear needed to be re-cut because the number of teeth it contained was inaccurate. After that everything came together like clockwork, no pun intended.
Steven Jimenez bores a hole in a shaft.
Q4: What were some of the main areas of responsibility in the design and building? Or, how was the work distributed?
A: It was important for the team to have structure and follow a manufacturing model that we would incorporate into our documentation and presentation during the competition. Our model included an eight-phase process – i.e., design, manufacturing, quality control, testing and refinement, etc. Each team member had a specific role. It was also important for each of us to learn new skills. After all, it is an academic competition.
In the beginning, everybody equally re-designed (Canadian clockmaker) Gary Mahony’s clock design and contributed constructive criticism. We used a computer-aided design (CAD) software known as SolidWorks to create a 3D parametric model of the clock. Once designing the clock was finished, we divided the team based on student talents and expertise. For example, during the manufacturing process we had Steven Jimenez, who used to work as a professional machinist. He would machine and direct other students on manually hand-lathed-cut parts of the clock.
Martin Aispuro – who is extremely talented with digital photography, digital design, and has an extensive knowledge of technology in general – was in charge of keeping an accurate photo record of each process in our model and the aesthetic design of the reports we had to create.
Kind of a Renaissance man, Felipe Ortiz is a very talented artist. His drawings contributed to the concept design and process – and to the final aesthetics of the clock. Working closely with Blake Cortis, our staff technician, he also learned various machining methods of during the manufacturing.
Michael Frausto has been part of the WESTEC team for three years and had lots of insight. His major roles included material procurement and keeping an organized “Bill of Materials” for the team to present in its final report. Mike also did some manual machining on some of the clock’s parts.
Roman Kuchma, another past WESTEC team member, worked heavily on the computer-aided drafting (CAD) models. Roman is a computer and software expert with an eye for artistic detail. He designed life-like images of the clock in various scenes...that really helped the team visualize the clock before it was built.
Ticking off a few statistics
The total cost for the “Kronos” clock was $2,165 – including $832 in tooling expenses and $817 in materials. Labor was free – and priceless.
Calculations were required to determine the following for the clock’s inner workings: simple pendulum period and length, gear moment of inertia, friction force, and torque.
The project took about 3.5 months from start to finish.
The manufacturing consumed 8 pounds of steel, 29 pounds of aluminum, and 200 pounds of brass.
It was also important for the team to have a voice – this would be Paul Katsumura, who works for Disneyland as a Jungle Boat Cruise captain. Because Paul had such a powerful stage presence developed at his job, he was our main speaker during the presentation.
As for me, as team project manager or team captain, I made sure everyone was working on their various roles and meeting our time constraints. I also assisted in each phase of manufacturing, helped to solve problems, and worked extensively on our documentation, which included the presentation and report.
Overall, everyone worked as a team. Almost every part on the clock had involvement from each team member at some point in the process, ranging from the design of a part to its final buffing.
Q5: Anything else you’d like to add?
A: I would just like to note that we all worked very hard on this project and sacrificed many important aspects in our lives, like our free time (which included winter and spring break), our personal lives (like spending time with our loved ones) – all in order to win this competition and prove to the manufacturing and engineering world that Cal State L.A. is a top competitor and a top producer of some of the finest students in the world.
Ian van den Bosch