Page 94 - The Toyota Way Fieldbook

Chapter 4. Create Initial Process Stability 71

empty containers that are collected by the material handler. The rack
is also deep enough to hold several containers of each part type, and
the exchange and replenishment of material is handled without inter-
rupting the operator.
Since each operator is not required to walk long distances, they can
install additional parts. This consolidation will reduce the number of
operators on the line by about 20 percent.
If these non-value-adding activities of many operators are consolidated
and “pushed” out of the work area, the resulting waste becomes the
burden of the material handler, who is now required to service many
customers simultaneously and must create an efficient work pattern
that will meet their needs. The material handler can drive a small electric
cart that pulls a chain of dollies carrying a large variety of “right sized”
containers for a large number of operators. Because this method
requires smaller containers with lower quantities per container, the
frequency of replenishment will be increased, which will increase inven-
tory turnover, a desirable characteristic; however, it will not increase the
labor needed. In fact, it is likely to reduce the overall labor requirement
for material handling.

Improve Operational Availability

Often, we find processes that struggle to meet the requirements of the customer.
The root causes are generally attributable to production opportunities that are
lost due to the unavailability of equipment. The causes for lost time are numerous;
however, they fall into two main categories:
1. In-cycle losses. These are losses that occur during the work cycle (as the
equipment is operating). They may include excessive motion and equip-
ment travel distance. One such case involved a spot welder who had a
six-inch stroke when only three inches was necessary to clear the work
piece. This extra distance traveled required two seconds every cycle. Cycle
losses are generally considered first because they may be easily corrected,
the improvement is immediate, and it is gained each and every cycle.
Multiplying the small amount of time by the frequency of occurrence
(every cycle), these small changes can amount to significant gains in oper-
ational availability.
2. Out-of-cycle losses. These generally occur when the equipment is not
operational. The losses per occurrence tend to be significant, but the fre-
quency of occurrence is less. One of the significant losses is equipment
setup or a tooling changeover. The principles pioneered by Shigeo Shingo,
known as SMED or Single Minute Exchange of Dies, can be used to