Analysis of a single-edge micro cutting process in a hybrid parallel-serial machine tool

This paper presents a novel micro machining process as an alternative to other micro machining processes like micro milling. Its main advantage is the simplicity of the cutting tool geometry compared to other complex micro tools. The basis of this process consists of keeping the cutting tool always tangent to its trajectory. To achieve this goal, an innovative 6 degree-of-freedom parallel machine tool with high stiffness and with the tool tip precisely positioned, has been designed and built. The new machine is based on a hybrid device composed of three PRS (prismatic-revolution-spherical) parallel mechanisms with a linear XY stage and a C rotational axis. In order to determine the cutting load on the machine and consequently, its deformation, a resultant cutting tool force model has been developed which considers all the angles of the cutting process. A machining strategy has also been developed which takes into account the tool geometry and the kinematic restrictions of the machine tool. As a result of the kinematic and dynamic modelling of the machine, it has been possible to establish the level of precision for a given machining strategy. From the tests carried out, it is shown that the proposed machining process combined with the parallel machine tool, is an alternative to micro milling technology.