This study describes the machining of the fine surfaces with a ball nose end-mill tool by a five-axis controlled machining center. In the present paper, we demonstrate that it is effective to maintain a constant contact angle between an end-mill ball nose and a work surface in machining in order to obtain the fine machined surface because this makes it possible to avoid an irregular luster (striped pattern) caused by a profile error of the ball nose on the machined surface. Moreover, it can be seen that the surface roughness (i.e., convexities and concavities) along the tool feed direction can not be overlooked in trying to obtain the fine machined surface such as a mirror surface. As a result, a new method is proposed to determine the optimum cutting condition to achieve the minimum cutting time considering the surface roughness along the pick direction and the feed direction under a constant surface roughness.
