Tool Path Planning For 5-Axis NC Machining Based On Iso-Scallop Method

With the rapid development of machinery, automobile, shipbuilding and aviation industry, the geometrical shapes of parts are becoming more and more complex. Multi-axis NC machining technology is used in many enterprises. Tool path generation is important for complex parts NC machining, and the methodology of tool path generation affects the efficiency and quality of parts machining. This thesis studied mainly on optimization of the tool path and the gouging avoidance in 5-axis NC machining.For optimization of the tool path: An improved iso-scallop method based on principal -curvature is presented according to analyzing the theory and character of 5-axis NC machining. The algorithm optimizes the direction of tool on the base of present iso-scallop method. An algorithm of distinguishing rapidly local surface shape is presented using the property of "normal transversal" in differential geometry. During finding the proper inclination angle, the influence of machining error is considered and the error, which is caused by the assumption of using local curvatures at the cutter contact point in approximating the neighborhood surface, is reduced. Non-linear error is computed and controlled.For the interference avoidance: By analyzing the present methods of dealing with interference, the drawbacks existing among them are put forward. This paper mainly analyzes three kinds of interference: avoidance of cutter contact point interference, rear gouging avoidance by circular approximation and rear gouging avoidance in complex surface machining.In order to demonstrate the efficiency of the algorithm presented in this paper, a simply and easy display verifying method on NC machining is presented. Many methods of tool path generation are used to compare with the algorithm presented in this paper, the result shows that the improved algorithm presented in this paper increases the efficiency of machining and improves the quality of machining.