FMEA Failure Mode Effect Analysis–TQM Method
No matter how healthy machine condition be it is likely to have
some breakdown some day or other. This is the fundamental behaviour of a
machine. Basically, a machine is a system comprised of subsystems further
distilled down to LRUs (lowest repairable units) i.e. components. It could be
stated that overall machine behaviour could be stated as a complex process. The
failure could occur due to non-performance of an LRU or a subsystem and so on.
This intensity and frequency of failure depends on quality of components,
maintenance initiative and its frequency and the quality of repairing
initiative. The intensity of machine failure is directly related to a very
crucial factor termed as 'severity' which depicts the level losses that could
affect the production system. TQM Method
of FMEA 'Failure Mode Effect Analysis ' is an area that helps in identifying
the loss effect on plant performance.
In the practice of identifying modes of failure of a machine, certain
clearly defined steps are available in what is known as “Failure Modes and
Effects Analysis”. This TQM analysis
is performed in four distinct steps, the first of which is identifying the
expected tasks to be performed by a particular machine in a specified period of
time. The first step basically details the expected performance of the machine
such that any deviation from the expected figure can be identified to perform
further steps. Quantifiable data is helpful in determining if the required
expectations of performance are being met, thereby ensuring that the fault is
identified before a major failure occurs.
This brings us to the intensity of the failure which can be
curtailed with early analysis. If the same failure had not been detected in
early stages, a breakdown that would result in higher downtime of the machine
would occur. Higher downtime corresponds to lower plant performance in a
specified period of time and higher losses.
Now, the second step addresses the questions brought up by the preceding
step of FMEA. In this step, a list of all the factors that influence machine
performance negatively or cause a breakdown is prepared. The purpose of such a
list is to have a database of failure modes which can thereby be used to make
improvements in the systems and subsystems to eliminate unnecessary risks
leading to breakdowns.
The 4 steps of FMEA can be divided in to two sections, the first two
steps concerning the failure modes and the last two steps concerning the
analysis of effects of failures. Moving on, the third step focusses on
identifying and defining the causes of all the failures in a particular
machine. This step prepares the maintenance department to deal with any kind of
repetitive failure more efficiently and effectively.
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