Experimental Study For The Drill Point Geometry To High Manganese Steel

In recent years, the rapid and continuous development in railway industry determines that the machining market of turnout rail maintain to stable growth trend. ZGMn13 high manganese steel, which is difficult to cut, is the most common material used for turnout rail.This paper studies the measures taken in the improvement of difficult-to-cut materials machining and summarizes the advantages and disadvantages of both unconventional methods and tool structure's in high-manganese steel drilling. A plan of using mechanic hold cutter and multi-facet drill with double point angles at outer corner and without chip-split groove is presented based on studying and analysis the problems in the drilling process of turnout rail.The mathematical model of drill point with flat clearance angle is established, and the drill point edge is grinded on WALTER five-axis CNC as grinding machine in order to implement the experiment of high manganese steel drilling.By means of experiments of both front inner edge impacting on drilling force and arc-edge impacting on the chip on the test platform, the point's geometry parameters finally is optimized. Comparison in axial force and torque between the optimized drill and simulation factory's drill is implemented shows that optimized drill is much better in chip-breaks and stability in drilling process. This paper also analyzes the problem of cutting tool sticking and long fold chip in the drilling process, sums up the impacts of drill type's corner of inner cut edge, arc edge, and cutting parameters on the drill process.