An Improved Reentrant-Bottleneck Heuristic for the Reentrant Hybrid Flow Shop Scheduling

Reentrant production system is a complex system, whose main feature is that the job is repeatedly processed on a certain machine or several machines in the system. According to the theory of constraint (TOC), this paper takes a seamless steel tube cold drawing production line as an example and models it as a reentrant hybrid flow shop scheduling problem (RHFS). A scheduling model with the goal of minimizing makespan is established. An improved reentrant-bottleneck heuristic (IRBH) is proposed, which contains the initial sequence generation method (ISGM) and the multi-position job insertion method (MPGIM). The ISGM is used to generate an initial sequence and the MPGIM is applied to the initial sequence to optimize the scheduling. The experimental results show that the IRBH can solve the RHFS problem effectively.