Chapter 7
Preplanning: The Perfect
Tool to Accomplish
Toyota’s Rule #1
Based on the four-year study by Stephen Spear and Kent Bowen, “Decoding
the DNA of the Toyota Production System” (Harvard Business Review,
Sept.–Oct., 1999), and my own observations when visiting NUMMI, Toyotas
Rule#1 is: “All work shall be highly specified as to content, sequence, timing,
and outcome.” They clearly understand that if they do not do an outstanding
job of designing and implementing a robust manufacturing system, there is
no hope that the output from that system will be world class. The quality of
the engineering that goes into the establishment of a manufacturing system,
in large part, is going to determine the levels of productivity, quality, delivery
reliability, cost effectiveness, investment control, and process cycle time
obtained from that system.
When I started with Packard in 1971, there was a world-class system in
place, which was used to develop effective manufacturing systems for each
of the wiring harnesses produced within the operations. Because of the high
cost of labor in Warren, the system was developed to drive the labor content
down to the lowest possible level without placing an unfair burden on the
operators or expecting them to work at an effectivity level (a combination of
pace and efficiency of movements) greater than 100%. But, this system not
only minimized the labor content, it also provided for minimum investment
and created a work environment that would be most conducive to good
quality, excellent delivery reliability, and optimum process cycle time.
182 ◾  Intelligent Manufacturing: Reviving U.S. Manufacturing
This system was called “preplanning” and it was taught to each industrial
engineer (IE) within the company as a major focus of the two-week IE
Training Program. When I went through the program, an entire week was
spent learning the very important principles and concepts that were part of
this system. Because it has been proved that the best way to learn some-
thing is by doing it, this is exactly how this part of the training program was
structured. A very small harness was selected and, during this week, the
entire preplanning process was utilized to develop a proposed manufactur-
ing system. There were some necessary shortcuts made, to accommodate
the time available, but the entire process was understood at the end of the
week as well as its value to the company.
So, just exactly what is preplanning? I think the best definition I can come
up with is that it is a structured system that is used to develop the optimal
manufacturing system for any product, which uses Methods Lab simulation
as the primary means to develop methods, flows, layouts, and standards.
After I had been introduced to this system, it seemed so logical and
beneficial that I assumed that preplanning, in addition to being utilized at
Packard, was a common industry practice. I later came to discover that this
not only was not a common industry practice, it was not even a common
industry practice within the wiring harness industry.
What Is the Common Industry Practice?
When I was transferred to Portugal, I had an opportunity to observeand
evaluate the various engineering systems that were in place to helpme
determine where improvement opportunities existed as well as to benchmark
systems that could be successfully introduced to Packard’s North American
Operations. There were a lot of good things being done in Europe, especially
in regards to Process Engineering responsibilities, but, their level of IE exper-
tise, which was a big strength at Packard, was quite primitive. I was amazed
at the process used to establish manufacturing systems for wiring harness
In Packard Electric, an industrial engineer and methods operator team were
given a preplan assignment, which contained one or more harness packages
to be preplanned. The length of the actual assignment was usually 20 to
24weeks, which was the approximate amount of time available from the point
when sufficiently accurate data were available to start the preplan process until
the preplanning needed to be completed so that preparations could be made

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