Figure 3.1 - Good maintenance and reliability management requires employee involvement and
good procedures
The reliability tactics are:
o
Improvising individual components
o
Providing redundancy
The maintenance tactics are:
o
Implementing or improving preventive maintenance
o
Increasing repair capabilities or speed
Variability corrupts processes and creates waste. The operations manager must drive out
variability: designing for reliability and managing for maintenance are crucial ingredients for
doing so.
Reliability
Systems are composed of a series of individual interrelated components, each
performing a specific job
If any one component fails to perform, for whatever reason, the overall system (e.g., an
airplane or machine) can fail
Improving individual components
To measure reliability in a system in which each individual part of component may have
its own unique rate of reliability, we cannot reliability curve
However, the method of computing system reliability (Rs) is simple
o
It consists of finding the product of individual reliabilities as follows:
o
Rs = R1 x R2 x R3 x etc. x Rn
o
Where, R1 = reliability of component 1
o
R2 = reliability of component 2
Component reliability is often a design or specification issue for which engineering
design personnel may be responsible
However supply chain personnel may be able to improve components of systems by
staying abreast of suppliers' products and research efforts
Supply chain personnel can also contribute directly to the evaluation of supplier
performance
The basic unit of measure for reliability is the product failure rate (FRI) firms producing
high-technology equipment often provide failure-rate data on their products
o
FR (%) = Number of failures.
X 100%
o
Number of units tested
o
FR = (N) = Number of failures
o
Number of unit-hours of operation time
Perhaps the most common term in reliability analysis is the
mean time between failures
- the expected time between a repair and the next failure of a component, machine,
process, or product
(
MTBF),
which is the reciprocal of FR(N):
o
MTBF = 1 divided by FR (N)