Dickeson--Lift, Pull and Other Dirty Words
"Lift" and "pull" are dirty words in the world of commercial printing. When you "lift" a form or job, you "pull" it off the press, binder or other process before it's completed.
You do this because you must put some other job or form in its place, in order to meet a promised delivery time. The practice impairs productivity, compromises quality and zaps profits.
"Well, if it's that bad," you say, "then why would anyone do it?" We do it because we've promised a delivery date we can't keep unless we interrupt the completion of forms or jobs already in process. Next question: "Why do we promise delivery dates we can't keep?"
First, we have expensive plants and equipment, creating a productive capacity we must fill in order to be profitable. So when the sales manager or CEO enters the production office and says, "Can you squeeze this job in?," we demur for a moment, but then yield in order to keep the peace—and maybe our jobs. This practice is commonly called "bliviting" (or forcing two pounds into a one-pound bag.)
Second, experience teaches us that we routinely lose perhaps 20 percent a year of existing business and must replace it and increase it if we're to grow. As a result, schedules become filled with work that may fall out and prospective jobs that haven't yet matured to order status (and may not). Call this the scheduling A&R (attrition/replacement) factor. We blivit to compensate and grow.
Third, we overlook the "Law of Chaos" probability in printing. This theory teaches us that small changes in input cause major changes in output. There are five clusters of variables in the printing process: materials, people, machines, environment and form sequencing. Minor variances within, and between, these clusters make process performance unpredictable. To these five internal clusters add a sixth—an external variable: customer schedule maintenance and specification compliance.
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.)
There are some good ones available. In addition, provide some slack time and use it for maintenance tasks if it doesn't get filled by problems. Improve customer communications.
Give serious consideration to production standards that are "ranges" rather than some kind of average. It's much more realistic to say, "This form will require between five and seven hours of presstime," rather than an unrealistic "5.6 hours." Let your computer give you standard deviations. Those little motherboards are so happy when you let them do that!
And this above all: Cherish your schedulers—give them support. When's the last time you gave a scheduler a "high five"? They work against incredible odds. The wrath of sales, marketing, every production department and the controller is visited upon the schedulers. It's the most gut-wrenching, thankless job in the plant.
Every time we pull a job—lift a form before complete—to meet some delivery schedule, we hurt ourselves. The buck stops here. The blame is ours. We created it, and only we can fix it.
—Roger V. Dickeson
About the Author
Roger Dickeson is a printing productivity consultant based in The Woodlands, TX. He can be reached via fax at (281) 419-8213 or e-mail at roger@prem-associates.com.
