A new method to support the design of assembly machines based on function modules

The use of mechatronic modules in machine design enables the development of standardized, easily assembled, and reconfigurable systems. With pre-engineered mechanical, electrical, and control modules, the machine development process can be accelerated, design risks reduced, and functional expansion facilitated. Existing approaches commonly treat assembly planning and module selection as separate steps, rely heavily on designer experience, and provide limited quantitative support for evaluating trade-offs between cycle time and module cost. This paper proposes a method to support the conceptual design of assembly machines by integrating handling-based functional modeling with a two-phase linear optimization framework for selecting suitable functional module variants (FMVs). The main contribution of this work is the transformation of handling functional sequences into a structured representation of material flow, which is then used to derive machine layout schemes, establish operational cycle constraints among modules, and formulate an FMV selection problem with two objectives: minimizing cycle time and minimizing module cost. Rather than preparing module data solely for manual selection from a library, the proposed approach integrates: (i) the construction of functional sequences to determine the operational order of each functional module; (ii) the development of a standardized FMV database containing technical specifications and cost information; and (iii) an optimization model that coordinates FMV selection within and across stations in assembly machines and assembly lines. The proposed method is illustrated through an assembly example involving a chip, socket, chip holder process on a rotary transfer machine. The results indicate that the optimization model can identify feasible machine configurations, determine cycle times under the adopted modeling assumptions, and explore cost reductions without degrading the optimized cycle time. Compared with existing studies, the proposed framework provides a more integrated treatment of time-dependent relationships among functional modules, supports the systematic exploration of large design spaces, and enables the concurrent consideration of cycle time and total module cost during early-stage assembly machine design.