Abstract: The present invention relates to a cutting method for cutting an upper edge and a lower edge of a cutting plane into a curved shape, when a cutting object is cut by supplying plasma gas to the periphery of an electrode of a plasma torch and ejecting plasma arc from a nozzle. In order to melt the upper edge and the lower edge of the cutting plane to form a curved shape, at least one condition selected from plural conditions including a cutting electric current, cutting speed, height of a plasma torch, angle of the plasma torch, and flow rate of plasma gas upon performing the vertical cutting for forming the upper edge and the lower edge of the cutting object substantially at right angles is changed.

Abstract: The present invention relates to a cutting method for cutting an upper edge and a lower edge of a cutting plane into a curved shape, when a cutting object is cut by supplying plasma gas to the periphery of an electrode of a plasma torch and ejecting plasma arc from a nozzle. In order to melt the upper edge and the lower edge of the cutting plane to form a curved shape, at least one condition selected from plural conditions including a cutting electric current, cutting speed, height of a plasma torch, angle of the plasma torch, and flow rate of plasma gas upon performing the vertical cutting for forming the upper edge and the lower edge of the cutting object substantially at right angles is changed.