Measuring method of sphericity of ball end mill

Abstract

A method of automatically measuring sphericity of a ball end mill on a machining device under nearly identical conditions to those at the time of machining. Under a cross rail 1 of the machining device, a laser measuring device (6) is placed through a mount (7) so that a laser optical axis 'a' is in the X-axis direction. A ball end mill T is fixed through a milling chuck (5) to a main spindle (4) carried rotatably by a main spindle ram (3) that can be positioned along the Z-axis direction of a main spindle head 2, which can itself be positioned in the Y-axis direction. While rotating, the tip of ball end mill T is set using laser beams. A position shifted by one radius of a tool from the tip is set as the ball center. One radius of a cutting face is measured by sliding the ball end mill on the nominal of the ball per an arbitrary angle within 90.degree.. The sphericity of the ball end mill T is obtained from the respective one radius at each angle.