1. Variation
• Variation affects every aspects of the
process and every specification of every part
of the product. It is present in the
materials, the manpower, the method, the
measurement and the environment to
manufacture product.
• Variation is; inevitable, applicable to all out
puts, system generated.

2. • Inevitable change in the output or result of
a system (process) because all systems vary
over time. Two major types of variations are
(1) Common, which is inherent in a system,
and (2) Special, which is caused
by changes in the circumstances
or environment.

3. Variation refers primarily to systematic
variations in demand for products and
services in a cyclical fashion at different
within a recurring time period. For
example, the demand for umbrellas is likely
to have a yearly cycle, in which the demand
will be high during rainy season and low in
other seasons.

4. Buffer
Whenever there is variation, we need
inventory to compensate for the variation if we
wish to maintain the production rate. A buffer
is some resource we have in excess that is
designed to account for a fact that a production
cannot be in perfect to look-step with
consumption.

5. Three forms of buffers
1. Inventory
we must accumulate finished goods between
customers pick ups.
2. Capacity
Requires a change over, a capacity buffer
3. Time
Managing to finish a project in an exact time.