Research On Non-interference Tool Path Planning For Five-axis Machining

With the rapid development of modern industrialization,put forward higher requirements for the manufacturing industry—superior of product performance,innovative of manufacturing methods,high precision of machining and short of production cycle.Five-axis machining was widely used in free-form surface machining with high-speed?high-precision and high efficiency characteristics.Although the five-axis machining brings an innovative and high-superior manufacturing method to the manufacturing industry,but also bring a lot of difficulties of the process planning,because of its plus two additional rotation axis relative to the ordinary CNC machining.In this paper,based on the theory of five-axis machining and the progress of research at domestic and foreign in the system of study,the aim is to improve the accuracy and processing efficiency of free-form surface machining,carried out basic study on the tool path planning algorithm for free-form with five-axis machining with a toroidal cutter.Through the analysis of the cutting model and the interference phenomenon,the tool interference problem is taken into account in the tool path planning,and the uniform chord error and maximum SIO-scallop curve of the tool path was planned.The main contents of this paper are as follows:Firstly,an interference detection algorithm based on projection method and mapping theory is proposed to solve the problem of interference detection of cutter contacting point in a tool posture on five-axis machining.The algorithm can effectively avoid the intersecting judgment of between the two surfaces,between line and the surface.The idea is as follows:According to the geometric shape of the toroidal cutter to decompose and establish the mathematical expression,and obtained the surface point to be measured of may interference by projection,when the interference detection is carried out,the workpiece coordinate values of the points to be measured are converted into the mathematical expressions of the toroidal cutter by the mapping theory,the interference judgment is made indirectly by comparing the values of the measured points with the tool mapping point in the Z-axis direction.which lays the foundation for the subsequent admissible area structure of non-interference tool posture.Secondly,a uniform chord error and maximum IOS-scallop tool path planning algorithm based on directional distance theory is proposed.The algorithm can effectively reduce the planning error caused by the approximation processing,and minimize the total number of cutter contacting point and tool-paths within the tolerance error range.The planning process includes two steps: preliminary calculation and precise correction.Firstly,the feed step and the lateral spacing are calculated based on the arc approximation method and the differentialgeometry method.Then,the feed step and the lateral spacing are precisely corrected by the calculated model of the chord and scallop error based on the directional distance theory,and finally the tool path curve covering the entire workpiece surface is calculated by recursion.Finally,based on the analysis of the kinematic principle of the five-axis machine and the relationship between the linkage axis,the calculation method of the data conversion of the tool-path tool position of the AC-type five-axis machine is proposed,and construct a temporary post processor of too-path based on UG NX8.0/Post Builder system.And then simulation and actual processing were processed in the Vericut software and Mikron UCP 800 Duro five-axis machining center,and compared with the results of traditional algorithms and commercial software MasterCAM 9.0.The experimental results show that the proposed method can effectively avoid the occurrence of interference in processing,and can greatly improve the processing efficiency on the basis of satisfying the processing quality.