Estimating operation times from machine center arrival and departure events

We develop a methodology for using bar code scanner timing information from an automated shop floor data collection system to estimate operation times within a flexible manufacturing system environment. The purpose of the methodology is to estimate mean operation times for multiple product types when the scanning only occurs when products arrive to and depart from a machine center. This methodology partially reconstructs the shop floor operations from captured bar code scanner timing information and then through the use of regression techniques estimates the mean operation times for each of the product types. This paper develops and evaluates the methodology within an operational context. The accuracy and precision of the estimators is evaluated via discrete event simulation under various experimental conditions to identify key factors which effect the performance of the estimators. We identified guidelines for achieving estimator accuracy and we applied the estimator to an actual industrial situation.