processing step, tool, supply, part, etc., or just plain having no work because
of no stock, lot processing delays, equipment downtime, and capacity
bottlenecks.
- Transportation or conveyance.Moving work in process (WIP) from place
to place in a process, even if it is only a short distance. Or having to move
materials, parts, or finished goods into or out of storage or between
processes.
- Overprocessing or incorrect processing.Taking unneeded steps to process
the parts. Inefficiently processing due to poor tool and product design,
causing unnecessary motion and producing defects. Waste is generated
when providing higher quality products than is necessary. At times extra
“work” is done to fill excess time rather than spend it waiting.
- Excess inventory. Excess raw material, WIP, or finished goods causing
longer lead times, obsolescence, damaged goods, transportation and storage
costs, and delay. Also, extra inventory hides problems such as production
imbalances, late deliveries from suppliers, defects, equipment downtime,
and long setup times.
- Unnecessary movement. Any motion employees have to perform during
the course of their work other than adding value to the part, such as reach-
ing for, looking for, or stacking parts, tools, etc. Also, walking is waste.
- Defects. Production of defective parts or correction. Repairing of rework,
scrap, replacement production, and inspection means wasteful handling,
time, and effort.
- Unused employee creativity. Losing time, ideas, skills, improvements,
and learning opportunities by not engaging or listening to your employees.
Ohno considered the fundamental waste to be overproduction, since it caus-
es most of the other wastes. Producing earlier or more than the customer wants
by any operation in the manufacturing process necessarily leads to a buildup of
inventory somewhere downstream. The material is just sitting around waiting
to be processed in the next operation. We should note that the main reason the
first seven wastes are so critical, according to Ohno, is because of their impact
on what we are calling the eighth waste. Overproducing, inventory, etc., hide
problems, and then team associates are not forced to think. Reducing waste
exposes problems and forces team associates to use their creativity to solve
problems.
The remainder of this chapter presents a big picture view of waste reduc-
tion. We discuss it in relation to the broader philosophy of the Toyota Way. We
also discuss value stream mapping as a methodology for building a big picture
view of waste reduction. In Chapters 4 through 9 we go into more detail about
specific tools and methodologies for waste reduction in the value stream.
36 THETOYOTAWAYFIELDBOOK
