Page 19 - Improving Machinery Reliability

There are numerous benefits to be gained by adopting profit-centered
maintenance. The central benefit is the concept of value that drives the
entire process to new levels of maintenance effectiveness.
Implementing profit-centered maintenance requires a long-term, life
cycle perspective and a commitment and willingness to invest for the
identification and root-cause correction of deficiencies. These are aimed
toward life extension and reduced life cycle costs by permanently
At
decreasing the need for and cost of maintenan~e.~ each step along the
way it is imperative to formulate and communicate credible financial jus-
tification and results of profit-centered maintenance to senior executives
and financial management.
Condition assessment, condition-directed maintenance, and proactive
problem avoidance are vital elements of profit-centered maintenance.
Much has been written about condition assessment and condition-direct-
ed maintenance; only the crucial value or profit-centered principles will
be repeated here. These include:

The mix of maintenance types, e.g., reactive, preventive and condi-
tion-directed, is determined by value considerations. Some machines
are most profitable run-to-failure. Others require full condition
assessment and condition-directed maintenance for highest profitabil-
ity. For most, greatest profit requires a balanced mixture of preven-
tive and condition-directed maintenance.
Detailed, diagnostic mechanical condition assessment from vibration
and fluid (lubricating and hydraulic oil) characteristics, electro-
mechanical condition from static and dynamic electric (current) char-
acteristics, internal wear, buildup and erosion from operating perfor-
mance and efficiency and external conditions (leaks, loose fittings,
unusual sound and smell) are all necessary for a complete, accurate
picture of condition.
Method of condition assessment, type and number of measurements
and interval between successive measurements must be based on sev-
eral factors. These include optimum methods to assess condition and
provide earliest detection of change, current condition, rate of
change, and the probability and consequences of failure. Anticipated
time between discovery of a potential failure and requirement for cor-
rective action as well as operating/production requirements and value
are other important considerations.

xvi