Evaluation of Dynamic Behavior of Machine Tools for Sculptured Surface Manufacturing

The production sector of molds and dies is under a continuous pressure for process optimization due the high lead time required for the production of complex tools. In recent years, to improve this sector, numerous studies have been aimed at optimization of the CAD/CAM/CNC chain. However, despite recent technological innovations such as development of cutting tools, machine tools, and process simulation systems, the machining step still represents a major bottleneck in this process. The current generation of Numerical Control (NC) programs that represents the tool path do not consider the dynamic characteristics of the machine tool in the decision-making process to choose the most appropriate cutting strategies, resulting in NC programs that do not reach levels of excellence. The main objective of this paper is to present the development of a reference index based on the dynamic characteristics of the Machine Tool to support the NC programming with a commercial CAM system. This index considers the Machine Response Time (MRT) of NC controller, the acceleration and deceleration on the axes of the machine tool and the tool path segment (size and inclination). The index makes possible an experimental evaluation of relationships between the programmed feed rate for the tool path and dynamic performance due to movements of the machine axes, thus becoming an important decision-making factor in choosing the best machining strategy and consequently a better plan of the production process in die and mold industries.