Indium Blog

Patty and The Professor 15th Anniversary

  • Dr. Ron Lasky

  • Folks,

    It is hard to imagine that it has been 15 years since “The Adventures of Patty and the Professor” debuted. It started with a few blog posts and it just kept on going on and on, finally resulting in a book. A second edition followed.

    I was touched a few years ago, at a meeting of about 15 people, when one of the attendees was speaking and he said, “We have all read Patty and the Professor.” Most recently, when I was at the SMTA Electronics in Harsh Environments Conference in Copenhagen, one of the speakers referenced Patty and the Professor in his presentation.

    My favorite story is still the first four blog posts. The first one is repeated below. To read the other three and obtain a copy of the complete book, go to this link. A short video on the book’s history is here.


    Dr. Ron


    Business was good at ACME. Even in these challenging times, the company’s three assembly lines could not keep up with demand. John, the manager of the assembly lines, decided to request the funds for an additional assembly line. A member of his team, Patty, suggested he might want to consult “the Professor,” before getting a new line. The Professor taught a course on line balancing that Patty had taken at the SMTAI conference the previous summer.

    Line balancing is an important part of optimizing productivity in electronic assembly. A balanced line ensures that the component placement process, usually the “constraint,” is the fastest possible by assuring that each placement machine spends the same amount of time placing components. If any machine is waiting for the others, assembly time is being wasted. In a sense, line balancing is an application of Goldratt’s Theory of Constraints. John remembered that when Patty applied what she learned from the Professor, throughput increased 25 percent.

    Unfortunately, Patty did not attend the Professor’s other class on “Increasing Line Uptime.”

    Figure 1. Patty and the Professor

    John decided to have a chat with Patty about the Professor. “Patty, why do you think I should consult with the Professor about getting a new line?”

    “Well, John, perhaps with some effort to improve our uptime, we wouldn’t have to buy another line,” said Patty.

    “That’s a good point,” replied John.

    Patty contacted the Professor and he agreed to fit ACME into his busy schedule. Upon his arrival, the Professor was given a tour. As part of the tour, he was shown the process that ACME used to minimize changeover time between jobs. The Professor appeared to be impressed. After the tour, the Professor asked if a brief meeting could be held with the engineers and managers to discuss the situation.

    “What is the average line uptime?” The Professor asked the assemblage.

    There was some hemming and hawing. Finally Pete, the senior process engineer replied, “I’d say at least 95 percent. We work our fannies off out there.” The nine or ten people in the room murmured in agreement.

    Finally, John spoke up, “Professor, what is your definition of uptime?”

    The Professor responded, “Simply the percent of time an assembly line is running.” Pete again responded that 95 percent was the right number.

    The Professor asked for some production metrics and performed some calculations on his laptop. In a few moments he commented, “From the data you gave me, I estimate that your average line uptime is about 10 percent.”

    Upon hearing this, Pete became red in the face, especially after Patty whispered in his ear, “I told you so.” The noise in the room became so loud that John was concerned he might have a riot on his hands. The Professor asked to speak and John, in a booming voice, asked for calm.

    “Let’s not become angry. Perhaps my calculations are off. Why don’t we measure the uptime for a few weeks to be certain?”

    “How do we do that?” Asked Pete, his face still crimson.

    “Each day, one process engineer will go out to the lines every 30 minutes. If the line is running, he will enter a 1 in the spreadsheet cell. If the line is not running, a 0 will be entered,” responded the professor.” The team agreed that this would be done and the Professor would return in two weeks.

    Will Pete’s red face return to normal? Will the line uptime be 95 percent? Will Patty and Pete ever be on speaking terms again? Stay tuned for the next episode.