Study On Technology Of Inner Whirlwind Enveloping Milling For Screw

Many of variform abnormity screw apply increasingly abroad in oil, chemical engineering, light industry, war industry, shipbuilding, rubber and so on along with mechanic industry developing recently. In single screw pump whose rotor has double or triple heads, the rotor whose section line has characteristics of discipline, convexity and smoothness is classical helical surface. External envelope method is adopted for NC milling technique. External turning face of cutter blade is made contact workpiece to envelope helical surface of spiral rod with dish tool.It is cutting smooth and efficient when cutting with traditional whirlwind milling method. And that CNC technique makes the trace controlled neatly. And that CNC technique trait of trace controlled neatly. In this thesis, combined these two together, we study on new method of inner whirlwind envelope. The relative movement-trace between milling cutter center and workpiece is used to envelope the helical surface relying on the rolling inner circular trace of the cutter. Inner whirlwind enveloping milling, which is greatly efficient, economical and practical, is a machining technology for milling screw. We usually machine triangular thread and trapezoidal thread by from tool of mill head with whirlwind. Trace controlling becomes neat and simple after combined with CNC technique. When the workpeice whose section line has convexity is machined by the technology, not only the gyratory surface of cutting edge contacts the surface of workpiece in longer line, cutting smoothly, and the machining time is diminished, but also the magnitude of helical surface roughness is reduced. This machining method combines highly efficiency of inner whirlwind and highly flexible of envelope to CNC machining method. According to characteristic of screw, this thesis studies a sort of arithmetic about spatial path of cutting tools, analyzes primary effect parameter, and proves feasibility of this method.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. Some problems are solved here, such as program reasonable tool route, definition of reasonable machining points, and reduction the error. The accuracy of machining workpiece is analyzed also in the article. Above arithmetic and simulation are realized with C++ BULIDER, generate a software of inner whirlwind milling multi-head screw in Windows 2000. This software is a suit of CAM software for calculating the trace of tool, displaying of graphics, and creating CNC file.