166 THETOYOTAWAYFIELDBOOK
had a goal for 25 jobs per day, so we set that as the volume target, even
though the total amount of work varied. This variation, however, was
handled by slight adjustment of the total work time each day and did
not affect the workload balance throughout the day. The mix included
two layers—the primary mix based on finish, and the secondary mix
of components. The primary determination based on finish provided the
correct mix to meet customer orders and workload, and the secondary
provided the correct mix for workload. Sequence of the orders by finish
helped to balance the workload, as did sequencing the components.
These changes were the foundation for establishing standardized
work and flow. Balancing the workload reduced the amount of line
stoppage and smoothed flow throughout the rest of the operations.
Future activities that connected operations reduced the “pile-ups”
that frequently occurred.
In a custom environment, it’s difficult to find an accurate measurement
for performance. There is always an element of variation that will skew
any measure. In this case, a longer view had to be developed, with the
idea that over a wider time window (one month) the variation would
be equalized. In other words, month over month we could begin to
see improvement in performance as measured by total hours required
versus total sales dollars. When performance was viewed over a six-
month period, the variation was equalized even further, and there
was a noticeable mean shift.Leveling Is an Enterprisewide Process
The single most common reaction we get when we try to teach leveling to com-
panies is: “Sales has their own incentives, and sales always comes first in this
company. They sell whatever they can, and we in manufacturing are expected
to build it, and sales can change by 100 percent or more from week to week.”
When we’ve examined the data more carefully, we typically find that actual
demand is much smoother than what manufacturing sees.
In one office furniture manufacturing company that built a large variety of
different filing cabinets, customer orders to the plant were unstable. Yet the cor-
porate policy was 100 percent build to order, and manufacturing was constantly
fighting fires to build whatever orders came in. This led to huge amounts of
inventory at every stage of production and no clear takt time anyplace in the
process. When asked what lead times they gave customers who ordered filing cab-
inets, the answer was six to eight weeks out. So the manufacturing plant was
working like crazy to build orders that were all over the place, but there were six to
eight weeks of nonvalue activities in the pipeline. Why couldn’t that time buffer
be used to level the schedule? If there was inventory of finished filing cabinets, at