On the assignment problem of arbitrary processing time operations in partially overlapping manufacturing resources

The frequent transfers´ challenge of workpieces between multiple resources is quite evident in the production process of customized parts. In fact, special jobs´ transfers and processing, often, require workpiece unloading, transport and loading with, rather, idling and reconfiguration of resources that impact much job completion time and resource utilization. The overlapping capabilities of machine tools, otherwise, are common with, typically, few special tooling. In such settings, the overlapping and special tooling capabilities intensify the complexity of the assignment problem, mainly, when allocating the operations of arbitrary processing times. This work targets the efficient assignment of unrelated jobs of operations with arbitrary processing time to multiple resources of partially overlapping capabilities. The work introduces a formal model and a more efficient solution approach for minimizing jobs´ transfer and balancing workloads. The sequencing problem of the assigned unrelated jobs would be, then, an orthogonal problem, of less significance, that can be tackled separately.