Capability Indices for Rayleigh Process

Monitoring, control and improvement of quality are  important  for companies.  Process capability indices (PCIs) are tools widely used by the industries to determine  the quality of their products and the performance of their manufacturing processes. Classic versions of  these  indices were constructed for processes whose quality characteristics have  a  normal distribution. But, many of these characteristics do not follow this distribution.  In such a case, the classic PCIs must be modified to take into account the non-normality,  because  the  effect of  this non-normality can lead to misinterpretation of the process capability and ill-advised business decisions. A non-normal model is the Rayleigh distribution  which is very useful. This paper proposes a Clements’s method to estimate the PCIs for Rayleigh  processes.  Finally, an example to evaluate its performance is presented.