Fabrication of ball end mills for high speed milling and their cutting characteristics - Experimental and geometrical evaluations of ball end mills with different helix angles and rake angles

High speed milling is being watched in die and mold machining in the light of high speed and high accuracy. Although ball end mills are the central tool widely used in high speed milling, they are fabricated by the commercial tool grinding systems without using effective 3D-CAD/CAM technology. Therefore, it is difficult to confirm and evaluate the tool shape information on fabricated tools. Cutting experiments are the only way to investigate fabricated tools. Moreover, it is difficult to quantitatively analyze tool shapes since the tool shape definition for ball end mills varies, depending on manufacturers. The study deals with the development of a tool grinding CAD/CAM system to design and create ball end mills with different helix angles and rake angles. The high speed cutting characteristics of fabricated ball end mills with different shapes are investigated through high speed cutting experiments and geometrical cutting simulations. As a result, it is found that the most suitable ball end mill for high speed milling is with helix angle 10° and rake angle -10° among fabricated ball end mills.