ESTIMATING PROCESS CAPABILITY INDEXES THROUGH RANDOM SAMPLES IN CVG-BAUXILUM

To calculate Capability Process Indexes, it is necessary to know the average (p) and the standard deviation (8) of some process parameters which are not always known. An estimated index is a random variable whose value may be higher or lower than the true value of the Cp or Cpk index. Technical support analysts often wondered what index would be best suited for the Bayer Process. The current paper examines some statistical methods of quality control to estimate the process capability of a bauxite and alumina plant from random samples in CVG BAUXILUM. Cpk, Ppk, Cpm, and other indexes were evaluated in order to suggest the best means of reporting the process capability. These tools and procedures have allowed the organization to make better decisions based on a set of analytical solutions and have provided an efficient method for determining optimal strategies and may offer improvement opportunities.