Experimental evaluation of surface generation and force time-varying characteristics of curvilinear grooved micro end mills fabricated by EDM

Abstract

Conventional cutting fluids as coolants and lubricants are being widely used in various machining processes, but these cutting fluids give rise to biological and environmental problems. The advantages of implanting micro texture on macroscopic cutting tools have been proved widely in implementing sustainable machining. But seldom studies focused on preparing micro texture on the surface of micro end mill with diameter less than 1 mm. In this study, an attempt has been made to create curvilinear grooved micro textures on the rear surface of double helical micro end mills with diameter of about 800 μm by electrical discharge machining (EDM) method for lowering specific milling energy and forces. Then, dry micro milling experiments were performed on aluminum alloy material using micro end mills with or without curvilinear grooved micro textures. The surface generated mechanism, force time- varying characteristics, specific milling energy, chip capacity and tool wear form of curvilinear grooved micro end mills in dry micro milling are revealed. Besides, the effects of structural parameters of micro textures and process parameters on specific milling energy and dry micro milling forces are discussed. Experimental results disclosed that the average specific cutting energy involved in dry micro milling process of aluminum alloy material machined by micro end mill with curvilinear grooved micro textures is decreased by 21.35%. The normal and tangential forces are significantly reduced compared to ordinary micro end mill. The voids and stomatal located in micro textures fabricated by EDM method are found to be conductive to store and accommodate some extrusion chips. For micro end mill with curvilinear grooved micro textures, the oxidative wear is more serious but the adhesion wear is slighter than ordinary micro end mill. This research is expected to prepare and optimize micro textured micro end mills suitable for dry micro milling process, which has important theoretical significance and engineering application value.