Research On The Material Removal Mechanism During Elliptical Vibration Assisted Cutting Process

Brittle optics materials, semiconducting materials and ferrous materialshave an ever-increasing application values in various fields. However, most ofthe brittle optics materials and semiconducting materials possess hard and brittlecharacteristics, and present anisotropy behaviors. And their fracture strengthalso approximate to their yield strength. Thus, there would be fracture and pitdefects on the machined surfaces obtained by conventional machiningapproaches. When machining the ferrous materials, the diamond cutting toolwould rapidly abrade due to the high temperature in the cutting zone caused bythe friction between the cutting tool and the workpiece. Therefore, it would bean urgent problem to propose efficient cutting methods for the machiningprocess of these hard to cut materials. Up to date, the elliptical vibration assistedcutting has been extensively regarded as a very promising method to substitutethe conventional cutting methods due to its superior performances, includingdecrease of the cutting force, decrease of the cutting heat and improvement ofthe abrasive behavior of the diamond cutting tool. Although a large amount ofefforts have been devoted to the EVC process, the essential mechanismunderlying the material removal process has not been well revealed. The lack ofthe understanding of the mechanism significantly limits the proposal ofoptimum cutting process. Thus, the material removal mechanism underlying theEVC is studied by the combination of analytic model, finite element model andcutting experiments.Primarily, considering the time-varying characteristics of the cutting depthand the cutting velocity of the EVC process, the continuous process is dispersedinto a series of equivalent quasi-static models (EQSMs). The dynamic cuttingmodel during a period is formed by combining the discription of the EQSMs.Take advantage of the dynamic model, the characteristics of the cutting depth,the tool rake and the cutting force are quantitatively researched. The numericalsimulation results demonstrate that thrust force depends on cutting depthobviously, the main cutting force is not; The peak of cutting force is greater thanthe conventional cutting method under the same conditions, the average cuttingforce is lower; There is a certain negative correlation between cutting depth andvibration frequency; Smaller HSR is conducive to the improvement of the geometrical quality of surface.Second, establish the finite element model of EVC cutting AISI1045steel with MSC.MARC, to observe the changes of stress, temperature in theEVC cutting process. The numerical simulation results demonstrate that thedeformation zone stress of EVC process is cycle mobile and EVC process ofcutting tool edge temperature exist periodic variation, cutting force depends oncutting temperature; There is a certain negative correlation between cuttingforce and vibration frequency; Friction reversal promote chip formation.Finally, Based on optimization design principles to design a non-resonantEVC cutting device. The cutting test of hard aluminum2A12and brass showthat EVC cutting makes the workpiece poor macro surface finish but far highermicroscopic surface quality than the conventional cutting. The vibrationfrequency increases and the horizontal elliptical vibration track are conducive toimprove the quality of surface geometry. EVC cutting can protect the cuttingTool edge against cracking and wear,but the rake face eroded by the workpiecematerial seriously,the area close to flank edge suffer certain amount of wear.