Dickeson--Lift, Pull and Other Dirty Words
Fourth are the plants that operate on a 24-hour, seven-day week plan. There's no weekend or holiday to provide some "slack" in the schedule to accommodate problems that inevitably occur.
What's the answer to eliminating pulls? A Black Box—a computer! Magic! Yeah! "Let's buy that scheduling software from Merlin Inc. and put it in a PC in the planning office. We know that run lengths are getting shorter, that our customers are demanding shorter lead times and lower prices, and that we're compromising more delivery dates every week. We must have an answer."
Before expecting a digital solution from a computer, let's think a moment. We know that computer programs still haven't found a practical solution to the classic salesman's routing problem. Ten or 15 years ago the Russians trumpeted that one of their scientists had developed a mathematical formula to handle the problem. Alas, it didn't work.
A computer program can handle a rover on Mars, but last I heard it can't figure the optimum route for the salesperson to follow next week in 12 cities at 12 different appointment times. Maybe some day, but not yet. Compared to scheduling forms and jobs in a commercial printing plant, routing a salesperson would be duck soup!
Brain vs. Box
Scheduling in printing must be done in the neural synapses of the human brain. The scheduling problem in the printing plant is impossibly dynamic—constantly shifting and changing—those infernal clusters constantly dancing around. A schedule solution for 8 o'clock won't work at 9 o'clock. It requires more compromises in a day than a Washington senator makes in a six-year term in office.
So, what shall we do to minimize lifts? Employ a smart scheduler who can use experience, common sense, judgment, an old-fashioned schedule board and a good production-center loading system. Merlin Inc. can provide computer software for work center loading. (This may be called a scheduling system, but it's really a loading system.)