3359 Ultra high speed micro-milling spindle directly supporting endmill shank by aerostatic bearings

Abstract

Recentry, high-speed micro-milling has attracted considerable attention for effectively manufacturing fine and precise machine parts with lower cutting resistance. However, as the tool diameter becomes smaller, higher rotational speed of a spindle has been strongly required for machining works at an optimal cutting speed. Therefore, this paper proposes a new machining method that an endmill cutter is directly supported by aerostatic journal and thrust bearings, and driven by air turbines to achieve higher rotational speeds. It was found that the proposed micro endmill spindle with the 4 mm shank could rotate at 400,000 rpm and cut grooves with the depth of 25 Pm on the aluminum alloy surface.