Page 92 - How To Implement Lean Manufacturing

CHAPTER 5

The Significance

of Lead Time

riginally, I was not even sure if I should include a special chapter on lead time.
Not that lead time isn’t important—it’s an extremely important Lean concept.
OBut lead time is discussed in several chapters such as Chaps. 3, 8, 14 and 15,
and though it is an extremely important topic, I didn’t want to overdo it.
However, lead time, when it comes to useful information in Lean manufacturing is
like onions in an omelet or cheese on lasagna—you just can’t have too much of it. And
so we have this chapter.
To cover lead time, we will:
• Look at its history
• Explain the benefits of lead-time reductions
• Review one case study
• Explain the seven techniques used to reduce lead time
• Explain why lead time is the “key” measure of Leanness

Some History of Lead Time
Until the JIT (Just In Time) movement got some traction in the U.S. in the late ‘80s,
there wasn’t much talk about lead time at all. One of the early books on JIT was Zero
Inventories (APICS, 1983) by Robert Hall, and although he put together a good review of
the Toyota Production System, he made virtually
no mention of lead time. There was, however, an
interesting treatment of lead time in The Goal (North “I often say that when you
River Press, 1984) by Goldratt and Fox. In addition,
can measure what you are
Richard Schonberger, in his book World Class Manu-
facturing (The Free Press, 1986), has some excellent speaking about, and express
it in numbers, you know some-
information on lead time and lead-time reductions.
These books were from the mid-1980s. But after thing about it; but when you
Ohno and Shingo published their books in the U.S., cannot express it in numbers,
and The Machine that Changed The World (Rawson your knowledge is of a meager
Assoc. 1990) by Womack, Jones, and Roos was pub- and unsatisfactory kind… ”
lished, the topic of lead times became more preva- Lord Kelvin
lent amongst Lean professionals. This was about

73