Robot task sequencing for a flexible assembly system with 3D printers

We examine a robot task sequencing problem for a flexible assembly system which consists of multiple 3D printers, two post-processing machines, multiple assembly machines, an inspection machine, and one material handling robot. The flexible assembly systems, which have been built in many large cities in Korea, are designed to produce customized products for start-up companies and individuals. In this paper, we develop a robot task sequence in order to operate the system efficiently. We consider cyclic scheduling, a process for a system in which the robot repeats a specified sequence in a cycle to produce identical items. The system behavior is then modeled with a timed event graph (TEG) and the optimality of the robot task sequence is proved by analyzing the workloads of resources and the circuit ratios of the TEG.