Including mechanical requirements in a bi-objective nesting and scheduling model for additive manufacturing

Abstract

Following the increasing relevance of Additive Manufacturing (AM) as Manufacturing-as-a-service (Maas), the AM scheduling (and related nesting) problem has been increasingly investigated. Due to their business nature, Maas companies are interested in minimizing both the makespan and the total tardiness; however, most of the literature focuses only on one of them. This work fills this gap proposing a mixed-integer linear programming (MILP) model that minimizes both makespan and total tardiness. In doing so, for the first time in the literature, considerations on parts’ strength are included. During nesting procedures, indeed, parts can be oriented in different ways, with this choice affecting not only the total processing time (as considered by the literature) but also the strength achievable: if this is lower than what planned, parts might fail unexpectedly with detrimental consequences. Thus, this work ensures that parts are produced with the required strength. In doing so, we focus on a parallel unrelated AM batch scheduling problem for metallic parts.