ON-LINE QUALITY MANAGEMENT: INTEGRATION OF PRODUCT INSPECTION AND PROCESS CONTROL

A growing recognition that quality management is an important factor in defining a firm's competitive position has led to renewed attention to this function and has resulted in implementation of elaborate systems for on-line quality control comprising product inspection and process control. Traditionally, these functions have been treated independently, with very little interaction. In this paper we examine, in detail, a scheme that integrates the two functions, and we demonstrate that such an approach can result in significant cost savings. The motivation for this work comes from our experience in a wafer fabrication facility that suggested that exchange of quality information between different stages of production could result in significant performance improvements. To illustrate this approach, we consider a specific environment characterized by a single-stage continuous production process whose status is monitored by an X̄ control chart. We assume that quality-related costs may be described as a function of the process output. This is analogous to Taguchi's quality loss function and may be interpreted as a generalization of conventional classification of process output as either acceptable or defective units. The integrative scheme essentially relies on utilization of the process status information (based on process control) in making product inspection decisions. For this system we derive a cost model and develop a solution procedure to determine optimal decision parameters. Limited computational results indicate that the scheme has significant potential for reducing quality-related costs.     

OARS: An order analysis and rescheduling system

This article describes an order assessment and scheduling system that was developed as an optimization-based decision support system for acceptance/rejection and management of orders in the IBM Austin Printed Wiring Board Plant. The need for an online system that could provide a rapid assessment of a customer enquiry and provide a quotation was a result of the changing business environment that needed to accommodate responsively new external customers in addition to its traditional captive market. The new environment emphasized technical marketing, requiring greater integration between engineering and manufacturing. The new system supports the information development tasks and decision issues in a greatly expanded market with proper division of tasks and degrees of decision autonomy.