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Due to high cutting speed and intermittent impact load, there exists significant friction and cutting vibration in milling process, which would lead to the mesoscopic friction damages. The friction damages and wear state thus become difficult to predict. In this work, the variation of instantaneous mechanical behavior of the milling cutter flank under vibration was studied. The structural deformation and friction damages of milling cutter flank in macro/mesoscopes were analyzed by conducting both thermal stress coupling field and molecular dynamic analysis. The multi-scale characterization method of instantaneous friction damage on cutter flank was proposed. The super-cell model of the tool-workpiece on the tool flank was developed. The variation of super-cell configuration was obtained. The nucleation and propagation of friction damages were identified; the evolution of mesoscopic friction damages on tool flank were revealed. The mesoscopic friction damage evolution of different positions on tool flank was researched; the coupling and competition mechanisms between the nucleation and propagation process of friction damages were unveiled. The cross-scale identification method of the friction damages of tool flank was validated by experiments. [ABSTRACT FROM AUTHOR]

In the process of high-efficient milling titanium alloy(Ti6Al4V) workpieces, the ICS (instantaneous contact stiffness) and its distribution between flank face of milling cutter tooth and workpiece change instantaneously due to cutting vibration, which makes tool flank friction and wear status be of instability. In this work, the tool flank micro-convex body stiffness model was developed considering the influence of cutting vibration on instantaneous tool cutting angles. The distribution of the ICS and its effect on instantaneous tool flank friction and wear increment were analyzed. The results showed that the changes in positive pressure on tool flank under cutting vibration was the primary reason for the non-uniform distribution of ICS; the friction and wear increment of different areas on tool flank were in direct proportion to the ICS. [ABSTRACT FROM AUTHOR]

The friction contact boundary between the tool flank of the milling cutter and the machining transition surface is important indicator to reveal the third deformation zone tool contact relationship and assessing the frictional wear performance of milling cutter. The existing models for friction boundary identification pay attention to the maximum width of accumulated friction and wear on the tool flank, ignoring the variability of the overall and local morphology of the friction boundary on the flank. Aimed at the influence of milling vibration on the instantaneous position of the cutter teeth and the machining transition surface, the solution and discrimination for the instantaneous position vector on the flank was proposed. Based on the mutagenicity of the instantaneous temperature and stress distribution, the influence of the instantaneous contact, extrusion, and deformation between the tool flank and the machined transition surface on the friction area was recognized. The calculation model of friction boundary of the flank was established. The irregularities of the distributions of the friction boundaries of the tool flank were revealed. The fractal recognition methods for instantaneous and cumulative friction boundary of the flank were proposed. And response was studied and verified with experiments. The results showed that it could effectively identify the irregular distribution of the friction boundary on the flank with the use of the above models. The formation and evolution of the friction boundary on the tool flank of the high-energy efficiency milling cutters were revealed. [ABSTRACT FROM AUTHOR]

Instantaneous friction and wear energy density are important indicators of the friction and wear state of the tooth flank of the milling cutter. Existing methods for identifying the friction and wear on the tooth flank of milling cutters mainly focus on the overall level of friction energy consumption and the maximum width of the accumulated wear on the teeth flanks, ignoring the unevenness and variability of the friction energy consumption and wear volume distribution of the tool flank, and the dynamic relationship between the instantaneous friction and wear on each tooth flank of the milling cutter is to be revealed. Transient cutting position of a high feed milling cutter tooth under milling vibration, and the use of the micro-element method to construct a model for solving the transient wear volume on the tool flank. A method of transient friction energy consumption on the cutter flank was proposed. The variation property of the instantaneous friction and wear energy density on the flank was exposed. The identification method of the variation property of the energy density was proposed according to different analysis results of the distribution of friction and wear energy density and verified by experiments. The outcomes indicated the maximum and mean of the energy density at different positions on the flank had a high similarity with the wear depth distribution on the flank. Using this method, the influence property of the friction and wear state and the cutting parameters under the milling vibration of the milling cutter tooth can be identified. [ABSTRACT FROM AUTHOR]

In the milling process, the friction and wear of the tooth minor flank of the square shoulder milling cutter directly affects the machined surface quality and the cutter's life. The friction of the minor flank of the cutter tooth presents a nonlinear distribution, and its variation cannot be revealed by using a single parameter. It is difficult to identify the dynamic characteristics of the friction of the minor flank of the cutter tooth. In this work, the friction velocity model for the cutter tooth minor flank was developed by using the relative motion relationship between the flank area element and the workpiece transition surface. In accordance with the atomic excitation theory developed under the potential energy field at the friction interface of the cutter, the model for friction energy consumption under the friction velocity and thermal-stress coupling field on the minor flank of the cutter tooth was developed. Based on the mechanism of the interfacial atomic thermal vibration, the model for the friction coefficient under thermal-stress mechanical coupling was developed. Using the instantaneous friction coefficient and normal stress, the instantaneous friction distribution function of the flank was obtained. Finally, an identification method for the friction dynamic characteristics of the shoulder milling cutter tooth flank under vibration was proposed and verified by experiments. [ABSTRACT FROM AUTHOR]