External aerodynamic force on an ultra-precision diamond fly-cutting machine tool for KDP crystal machining

Abstract

In the ultra-precision fly-cutting machine tool, the speed of the spindle is very high and the distance between the tool holder and the workpiece is small. There will be normal aerodynamic forces below the tool holder and on the workpiece under the influence of external air. The aerodynamic forces will directly result in the vibration of the machine tool and further affect the surface topography of the workpiece. This paper mainly studies the external aerodynamic forces on a fly-cutting machine tool. It results from the periodical and intermittent sweep between the rotating tool holder and the workpiece. The method of computational fluid dynamics (CFD) is adopted to study this phenomenon. Besides, the aerodynamic forces at different spindle speeds are compared. With the increase of the spindle speed, the amplitude and mean value of the aerodynamic force grows regularly. The aerodynamic forces on the slide and below the tool holder when the cutter processes different regions is presented. The aerodynamic force on the slide shows different behaviors at different machining positions along the feed direction. However, the aerodynamic force below the tool holder is identical. The simulated aerodynamic force on the workpiece is well coincident with the experiment results.