A generic classification and object-oriented simulation toolkit for SMT assembly equipment

Applications of computer simulation for surface mount technology (SMT) assembly lines have addressed many aspects of supply chain management, e.g., estimating cycle times, evaluating production equipment and line configurations, optimizing throughput and assessing product design for manufacturability. The implementation of an SMT machine simulator typically requires specialized code based on cycle time characterization experiments for the given machine type. This paper describes a generic simulation toolkit based on a classification of current SMT equipment. A detailed survey of machines has led to the definition of machine families and a generic machine model. A simulation toolkit consisting of object classes written in C++ has been developed to represent the generic machine model. Object-oriented design has enabled the construction of an object hierarchy that models the physical structure of a machine and its operation. A machine definition language has been specified to let the user configure the toolkit for a particular machine. The concept of a "snapshot" object is introduced, as a way to capture simulated operations for both parallel and sequential processes. Finally, this paper presents an application of the toolkit in the optimization of SMT machines. Results are presented for the Universal GSM2, a gantry-type machine.