OPTIMIZATION OF MACHINE SETUP AND TOOLING USING PRINCIPLES OF GROUP TECHNOLOGY

A number of the problems which arise in batch manufacture are a result of the high variety of components produced. One of the basic features of group technology is to reduce this variety by effectively sorting components requiring similar processes into families to increase efficiency and productivity. This research is concerned with the development of a system called OPSSP (OPtimization of Setup and Scheduling of Parts) to eliminate some of the inefficiencies by optimizing the setup time, and sequencing similar tooling parts for scheduling on the machine. Furthermore, as a step toward the completion of automated process planning of parts, the system is designed to select appropriate holders for cutting tools, and prepare detail work instructions containing the clamping device and a list of required tooling for parts. The system is also designed for rotational components produced on turning equipment and is especially suited to numerically controlled machine tools, and is capable of analyzing machines with as many stations and tool positions as required. Workpiece requirements is described by developing a procedure for classifying operations and forming attribute libraries for identifying the tool characteristics effecting the performance of operations. The classified tooling requirement is then used as an input to the computer program. The program analyzes the input information by considering the relationship and tooling similarities of every combination of two parts (the part on the machine and the part to be scheduled next) by comparing every corresponding operation, its cutting tool, and tool holders. During the comparison the program detects tool changes and assigns a preestablished unloading and loading time for every element of setup change. Since there may be many tool positions on every station of the machine, and therefore many possible ways of tool setting, the program generates a so-called index matrix. After establishing an optimum sequence of parts, the tool setting procedure dictated by the index matrix produces the optimum tooling arrangement. Finally, a matrix containing the time required to change the setup from one workpiece to another is developed and used in conjunction with an optimization algorithm for establishing the optimum sequence of parts for scheduling. The entire system is designed to permit a user to modify or make appropriate alterations to suit his/her specific requirements. The verification studies indicate that the system is capable of producing realistic and practical results and can effectively be used for achieving optimum tooling, setup, and processing of parts