| In available workspace of the orthogonal turn-milling process system, the workpieceis processed at different positions and poses of cutter. General dynamic characteristics ofthe multi-axis process system are different at different relative positions and posesbetween cutter and workpiece. During multi-axis process, processing stability isinfluenced by dynamic characteristics of the overall process system. At present, theprocessing stability modeling commonly used does not consider the changes of dynamiccharacteristics of the overall process system. To solve this problem, general dynamicstiffness modeling method for the overall process system and stability analysis fororthogonal turn-milling were both carries out.With the help of ADAMS software and ANSYS software, a system of rigid-flexiblecoupling model for the overall process system is established. Through establishingdynamic model for two subsystems, which are process system “machine tool-cutter” andprocess system “machine tool-workpiece”, the relative transfer function of the processsystem “machine-tool-workpiece” is obtained. Thereby general dynamic stiffness fieldmodel for the overall process system is established. The rigid-flexible coupling model ismodified by experiment and simulation methods. Based on it, the dynamic stiffness fieldsimulation is carried out. Two indicators of general dynamic stiffness index, bound-widthand over-flexibility, are proposed, which quantitatively describe frequent interval anddegree of dynamic stiffness softening for the multi-axis process system. The dynamicstiffness of the entire workspace field is obtained by simulation, and the influence of thetravel of each axis on general dynamic stiffness is analyzed.In order to analyze machining stability of orthogonal turn-milling, cutting forcemodel is derived. Both of no-eccentric machining stability model and low-eccentricmachining stability model are established. Lobe figures of two-dimensional andthree-dimensional stability are obtained by calculation. The influence of the overallprocess system of the general dynamic stiffness characteristics at different processingpositions on the processing stability models is analyzed, also the influence of processing parameters such as axial feed and eccentricity on the no-eccentric machining stabilitymodel and the low-eccentric machining stability model is analyzed.In this paper, simulation modeling of the overall process system of the generaldynamic stiffness is proposed. The research on machining stability based on the overallprocess system of the general dynamic stiffness characteristics is initially carried out,which can be used to guide the efficient and stable machining of orthogonal turn-millingfor shaft parts. |
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