Page 58 - Lean six sigma demystified

Chapter 2 Lean Demy S tifie D 37

Value Stream Mapping

The other sign you often see in the London
Underground is a tube map (Fig. 2-2). Although
much more interconnected than a typical value
stream map, you’ll notice that the stations are Oxford
quite small and the lines between them quite circus
long.
This is true of most processes; the time
between stations is much greater than the time Piccadilly
circus
spent in the station. As this map suggests, 95%
of the time is between stations, not in them. If
you want to reduce the time it takes to serve a FIGURE 2-2 • Tube map.
customer, you have to mind the gaps.

You Already Understand Lean

To think that mass produced items are cheaper per unit is understandable—but
wrong.
—Taiichi Ohno

I’d like to suggest that you already have been exposed to and understand the
concepts behind Lean. Kitchens, for example, have long been designed as
“Lean cells” for food preparation. The refrigerator, sink, and stove should
form a V-shaped work cell. The tighter the V,
the less movement is required of the cook. Sink Trash Refrig-
My kitchen looks like the diagram in Fig. 2-3: erator

Food comes out of the refrigerator, gets
washed in the sink, cut up on the counter, Micro-
wave
cooked on the stove, and delivered to the
table. Unlike mass production where differ-
Pots
ent silos would be put in charge of frozen pans Stove Utensils
and refrigerated food, washing, cutting, and
cooking, there’s usually only one cook that FIGURE 2-3 • Lean kitchen layout.
handles each of these steps. Each meal is a
small batch or lot. You never cook in batches big enough for the entire week.
A trip to the supermarket each week replenishes the limited inventories of
raw materials required. Ever noticed how most kitchens are right off the
garage? That way each week’s groceries come straight out of the garage right