Parameter determination method for twist drill point thinning using “Kompas 3D”

Standard twist drills have significant design flaw: chisel edge rake angles have large negative values. Chisel shortening with abrasive tool is commonly used to minimize this disadvantage. The choice of such a tool, tool parameters and parameters of its location relative to the drill affect point thinning measure and rake angles of the thinned cutting edge. Difficulties of abrasive tool selection are related to the presence of drill helical flutes and their intersection with the major flanks. The paper presents a method for determining rational parameters of point thinning based on classical solid modeling using “KOMPAS 3D” software. The method uses the following parameters: abrasive wheel diameter, wheel profile radius, inter-axial distance, distance between the wheel axis and the drill cutting part, angle of crossing of their axes and angle of the wheel base end rotation relative to the base axial plane of the drill. The maximum value of the drill side rake in the considered drill part is taken as the selection criterion. The technique is based on developing a parametric model of standard drills, with automatic model updating according to drill dimensions specified in the standards. The chip flute is modeled using helical movement of the standard milling cutter surface. The technique is developed for industrial plants specialists `who are involved in further tool development for specific production conditions.