Cutting Properties of Austenitic Stainless Steel by Using Linear Polarized CO<sub>2</sub> Laser without Assist Gas

Abstract

Recently, laser cutting is used in many industries. Generally, in laser cutting of metallic materials, assist gas and its nozzle are needed to remove the molten metal. However, because of the gas nozzle should be moved closer to the position about 1 mm from the surface of a workpiece, it is thought that existence of the nozzle causes lack of flexibility of laser cutting. Therefore, the new cutting process, Assist Gas Free laser cutting (hereafter, called as AGF laser cutting), has been developed and investigated about cutting properties in our laboratory. In this process, the pressure at the bottom side of a workpiece is reduced by a vacuum pump, and the molten metal can be removed by the air flow caused by the pressure difference between both sides of the specimen. On the other hand, when cutting of metallic materials with a linear polarized laser is performed, it is known that the cutting kerf might slant. This phenomenon is also observed in AGF laser cutting. In the present study, cutting properties of austenitic stainless steel by using liner polarized CO2 laser in AGF laser cutting was investigated. Cutting speed and direction were varied in order to study the effect of these parameters on cutting properties. As a result, when the angle formed by the cutting direction and the polarized direction of laser was parallel, the kerf slant could be depressed, and the critical cutting speed could be the fastest in any other cutting direction.