Statistical Process Control for Monitoring and Reducing Variation in Analytical Measurement

Aim : An extremely important issue in quality management is monitoring and diagnosing processes, and, subsequently, supervising them using so-called control charts. Background : Classical scheduling theory takes a narrow, static view of performance. In reality the assessment of scheduling performance is a particularly difficult task. In typical production processes, charts with constant parameters are commonly used, such as x-R, x-s, CUSUM, EWMA and others, which, in most cases, are effective tools for process stability evaluation. Charts considered untypical (in statistical process control) are those with variable sample sizes, variable sampling intervals and/or variable control limits. Such charts are used when process analysis based on standard, well-known charts may lead to serious errors. Objective : Modern control charts are a response to the requirements of Industry and are an excellent tool for supervising production processes. Their use together with Cp and Cpk indices and other process capability indices is a starting point for process improvement. Method and Results : The methodology of preparation of nonstandard charts is inadequately recognized and rarely used in practice. onclusion: The theory of their design and examples of their use will be presented and characterized in this paper.