Minimizing backtracking distance for networked operations in smart manufacturing

Abstract

ABSTRACT A novel integer programing (IP) model is developed to assign various operations of product variants to candidate machines and select the best place for each machine among the candidate locations. Product variants are considered to have operation sequence flexibility which are optimized for each product variant. The objective is to minimize the total backtracking distance by considering the production volume of each variant. Backtracking occurs when the production flow is upstream. Minimizing backtracking will improve forward production flow and reduces unnecessary distance travelled by parts which can lead to significant reduction in cycle time and improve machine utilization and total system throughput. In the literature, backtracking problem has been addressed in generalized flow line (GFL) problems, and flexible manufacturing systems. There is no work in the literature considering product variants with networked operation sequence as well as machine selection for each operation. A non-linear mathematical model is first formulated, then converted to an equivalent integer programing (IP) model and solved. A family of engine cylinder blocks is used as a case study for demonstration. The obtained results reveal that minimizing backtracking can significantly improve the total throughput and reduce the total traveling distance (33.33% and 27.78%, respectively, in the case study).