Page 402 - Improving Machinery Reliability

366 Improving Machinery Reliability

The basic idea of TPM is that equipment effectiveness must be maximized
through elimination of all defects, downtime, slowdowns, and so on.’
Equipment Effectiveness. There are two objectives in improving equipment effec-
tiveness:

maximizing output
minimizing input

Productivity defined as outputhnput is therefore increased.* Output is not simply
product volume. Factors such as cost, delivery, and quality must be measured as
well. Even safety, pollution, and attitude can be considered outputs to the production
process, and must somehow be measured and controlled. The main inputs to produc-
tion are labor, material, equipment, energy, facilities, and land. Cost of inputs must
be monitored and reduced. It should be noted that although the cost of all inputs has
risen in the past few decades, for many industries automation has decreased the
labor, facilities, and land components at the expense of the remaining three.
Running equipment effectively under ideal operating conditions to achieve maxi-
mum productivity is the central concept of TPM. This means eliminating the losses
and waste listed above. It is, therefore, necessary to establish a measurement system
for these variables, and to track progress in eliminating them. The measures must be
easy to record accurately; otherwise, people will not bother inputting data. There are
other calculations that should be made. Equipment availability measures the percent-
age of time a machine is available for production. Operating efficiency incorporates
the percent difference between ideal and actual machine cycle times, as well as the
maintenance of a given machine output over the operating period. Overall equipment
effectiveness is the product of the latter two percentages and the rate of good quality
product (Le., 100% minus defect rate). Other measures include MTBF (mean time
between failures), the number of improvements suggested by employees, and per
capita training expenditures. (See page 246 for more data.)

Autonomous Maintenance. In North American companies, labor unions and man-
agement have formed a clear separation between maintenance and production. This
is the most obvious reason for the slow acceptance of TPM, or more specifically
autonomous maintenance. However, some North American companies have over-
come this stereotype and have benefited accordingly. Better communications,
improved employee attitudes and placing responsibility for preventive maintenance
and minor corrective maintenance at the front line, all lead to improved equipment
effectiveness.
Autonomous maintenance requires not only a change in corporate culture, but a
heavy investment in training. Operators who have always said, “That’s not my job
(problem), call maintenance,” must now acquire a sense of ownership as well as the
skills for implementing their new accountability. Operators are asked to keep the
equipment clean, well-lubricated, and secure. Minor repairs and adjustments are also
operator responsibility. Each operator is trained and empowered to inspect, measure,
continuously diagnose, and fix problems.