A hole-machining process planning system for marine engines

This study proposes a hole-machining process planning system for marine engines, which converts industrial field requirements to the rules of the system. Unlike a fully automated system, the proposed system satisfies the requirements effectively by allowing the user to choose and to edit the rules. A computer-aided process planning (CAPP) system is comprised of Hole Manager, Cutting Sequence Definition, and Operation Manager which are derived from the conventional knowledge based system. For the purpose of efficiently coordinating the system operations, a procedure is proposed as: (a) defining priorities for each operation, using properties for the nested cutting, the number of tool changes, the directions of the tool, the tool diameter, and the hole height, (b) calculating the score for each operation with the related priority level, and (c) sorting of operations by the score in an ascending order. This idea is quite simple but yields a significant efficiency along with a high flexibility. By changing the priority of elements, various operation sequences can be obtained. The proposed method also considers multi-axis machining and the use of special attachments. This paper describes the construction of a practical hole-making CAPP system that satisfies the specific requirements of marine engine machining. The applied examples are machined by using the proposed system, including an engine block and a cylinder header.