Aplicação de cartas de controle de médias móveis exponencialmente ponderadas (MMEP) no monitoramento de processos: um estudo de caso numa montadora de automóveis

Abstract

This document is a case study that aims to apply Exponentially Weighted Moving Averages EWMA) control charts to monitor industrial processes in an automaker in the State of Paraná, which already uses Shewharts control charts. It discusses the performance of both graphics in detecting processes deviations by examining the Average Run Length (ARL) and comparing the obtained results. It is proved a higher sensibility and faster detection of variations using exponentially weighted moving average control graphics, which allows sample reduction without loss of reliability of control, by only increasing the frequency of controlled sample collection. It discusses the importance of process capacity on the quality of statistical control and estimates the positive financial impacts from sample reduction obtained through EWMA control charts.