By Jim Fitch
The field of maintenance technology is going through a revolution of change. Gone are the days when a machine had a predictable service life, after which it was replaced, continuing the cycle. Today machinery and equipment can be maintained to achieve useful operating lives many times that attainable just a few years ago. It is no longer a truism that all machines are built to fail. Why? Because there is an increasing understanding of the causes of failure, and, armed with this information, it is possible to prevent the initiation of failure proactively. The field of proactive maintenance targets this very objective.
When maintenance is performed in response to failure it is called breakdown maintenance. When maintenance is performed according to a schedule it is called preventive maintenance. When maintenance is performed in response to a detected impending failure it is called predictive maintenance. When maintenance is performed in response to detected conditions that avoid the onset of failure (by correcting the conditions) it is called proactive maintenance.