Kinematics and undeformed chip geometry in helical milling

Helical milling can be seen as an alternative to conventional twist drilling. It is used to generate boreholes by means of a milling tool being operated on a helical path into the work-piece. This work describes the kinematic contact conditions during helical milling and the resultant undeformed chip geometries due to the specific contact conditions. For the mathematical description of the undeformed chip geometry two approaches for calculating the axial depth of cut, which depends on the angle of rotation, are compared. Based on this, the ratio of the material volumes cut on the axial and peripheral cutting edge can be calculated. The results show that the volume ratio only depends on the ratio tool- and workpiece diameter