The development of CAM system for design and manufacturing of end mills becomes a key approach to save the time and reduce cost for end mills manufacturing. This paper presents the calculation and simulation of CNC machining end mill tools using on 5-axes CNC grinding machine tool. In this study the process of generation and simulation of grinding point data between the tool and the grinding wheels through the machined time are describes. Using input data of end mill geometry, wheels geometry, wheel setting, machine setting the end mill configuration and NC code for machining will be generated and visualized in 3 dimension before machining. The 3D visualizations of end mill manufacturing was generated by using OpenGL in C++.