IMPACT OF MACHINE DUPLICATION ON PROCESS QUALITY IN MANUFACTURING SYSTEMS

Abstract

The decision of duplicating work stations in assembly line balancing (ALB) problems is traditionally made based on production rates and economics of operations. However, duplicating production facilities is considered to be a source of variability that affects the process quality. Hence, the product quality requirements and the cost incurred due to variation in the output quality should be considered while making such a decision. In this research, a single-model, deterministic ALB problem type-1, with the option of duplicating work stations is considered. The problem is formulated as a zero-one integer programming model with the objective of minimizing the cost per period associated with operating stations. This cost may include labor, overhead, maintenance and fixed cost of the capital investment of the equipment over its expected service life. To incorporate the quality considerations of the final assembled product while solving the problem and making duplication decisions, the concept of quality loss is applied on the final assembled product. Taguchi's quadratic loss function is used to estimate the monetary loss incurred due to deviation of product quality characteristic from its target value. The average quality loss of the final assembled product is incorporated into the objective function. This leads to the development of a quadratic zero-one integer programming model. The developed model is linearized and an illustrative problem from published literature is considered for model verification.