The Mechanism Of Thread Whirling Geometrically Shaped Raceway And Prediction Of Surface Morphology

The Whirling machining is an efficient, accurate, green thread processing technology which can be classified into the internal and external whirling depend on different ways to process. The whirling machining could realize heavy cutting, cutting materials difficult to machine and ultra-high-speed cutting with high economic efficiency. However, it is complicated that the geometric forming mechanism of the screw thread. Along with the rotation and translation of the cutter wheel, the tool path is constantly changing, meanwhile, work-piece is synchronously rotating in the corresponding. the both coupling motion form the surface of the three dimensional spiral screw raceway. Therefore, the mathematical methods of the screw raceway geometry and forming mechanism and simulation methods of three-dimensional surface topography of the raceway under the whirling machining has been studied. The main work is as follows:First of all, the screw thread whirling coordinate systems are analyzed and constructed based on homogeneous coordinate transformation principle. The parametric models of the whirling cutter edges and screw raceway are established. Consider of the impact of synchronous rotation of the work piece and the inclination angle of the cutter, it is analyzed that the screw thread whirling raceways trajectory envelope surface based on the screw raceway geometry and forming mechanism.Secondly, On the basis of the above study, screw raceway 3D surface topography model is established through Boolean operations between the surface of semi-finished product and trajectory surface of the cutter. In order to analyze the composition characteristics and influencing factors about raceway 3D surface topography, Three-dimensional assessment of the raceway surface roughness indexes is studied based on above model. Consider of that the tangential and radial scallop constitute theoretical surface morphology and these scallop are closely related theoretical surface morphology and the cutting process parameters, the evaluate indexes of radial scallop height and tangential scallop height of raceway are proposed. In the meantime, the corresponding computational models are given in the paper.Finally, based on the above study, the above models are simulated by Mathematica numerical software. Screw raceway 3D surface topography visualization program is also realized by Mathematica numerical software. cutting parameters of whirling screw raceway have influence on raceway 3D surface topography which is analyzed and researched by this visualization program. The simulation results show the feasibility of the method of the present paper.