Study On Whirlwind Envelope Milling Theory And The Application On Extruding Screw Machining

Along with the development of the society and economy, the extrusion screw is being applied in the rubber and plastics industry extensively with its special advantage. Currently, the method of general turning or simple numbers control turning was mainly used in the process of extrusion screw in the domestic. But the efficiency is very low, and the accuracy can be hardly guaranteed. In this thesis, based on the studying of extrusion screw characteristic and whirlwind envelope milling theory, for expanding the application of three-axial non-instantaneous external envelope method and further increasing the accuracy of the screw and the machining efficiency , non-instantaneous envelope method and internal whirlwind milling technique are combined together. This method is the first time adopted in the domestic. According to the principle of envelope and the characteristic of helical surface, a kind method to calculate tool-path, which is simple in way and quick in speed of calculation is investigated aiming at cutting curved face of screw.In this thesis, the method and steps for studying tool-path are confirmed based on research and summary of machining and technique of free surface and spiral surface. A set of tool equipment is designed for NC machine. Some problem such as program reasonable tool route, definition of reasonable machining points, reduces the error are solved here. The accuracy of machining workpiece is analyzed also in the article. Above arithmetic and simulation are realized with C++ Builder, CAD/ CAM software UNIGRAPH1CS.Whirlwind envelope method and its tool equipment not only change the present condition that can only manufacture extruding screw by general turning or simple numbers control turning, but also can increase to process the efficiency of the extruding screw and obtain the high quality of the extruding screw. It will improve our rubber and plastics industry, and promote our national economy.