The Non-resonant Elliptical Vibration Turning Of Microstructured Surfaces

The microstructured surfaces have been widely used in the field of optics,biomedicine, and mechatronics in recent years. As a result, the manufacturing industrynowadays is focusing on the research of various methods of processing microstructuredsurfaces with higher efficiency and lower cost. With the consideration of the existingmanufacturing technology, elliptical vibration turning stands out because not only itsimprovement of the machinability, but also its ability and potential of manufacturingmicrostructured surfaces with low cost and high precision. However, there are someproblems to be solved in the research of elliptical vibration turning of microstructuredsurfaces as yet, such as the layout analysis of cutting devices, the diversified machiningmethods of microstructured surfaces, etc. Therefore, a novel processing scheme ofmicrostructured surfaces and a non-resonant elliptical vibration machining device aredeveloped in this paper, verified with simulation analysis and offline test. At last, thedesired irregular microstructured surfaces have been acquired by online turning.Before the design of the cutting device, the formation rule of surface morphology inelliptical vibration cutting has been analyzed; therefore, a novel processing scheme ofmicrostructured surfaces which randomized the amplitudes of elliptical vibration hasbeen put forward. Then the layout which the two axes was parallel arranged has beenselected by analyzing two methods of generating elliptical vibration. Piezoelectric stackshave been used as actuators here. Motion generated by actuators was guided to toolapron by flexible hinges. Thereby, elliptical vibration can be generated at the diamondtool nose in the end. According to the requirements of experiments, theoreticalcalculation and simulation analysis of the parameters of flexible hinges have beencarried out. After the processing and assembling of cutting device, an offline test systemhas been set up with a Newport air bearing vibration isolation platform, a multi-axismotion controller, a Siemens industrial personal computer, a capacitive displacementsensor, a signal generator and other equipments.According to the offline tests results of the non-resonant elliptical vibration cuttingdevice, it’s static stiffness is46.33N/μm, which is similar to preceding design value and simulation value; the natural frequency test results is807Hz, which is lower comparedwith the simulation value, but it still satisfies the requirement of experiments; welldynamic performance can be tell through the step and sine response test results. Variousdesirable elliptical vibration trajectories have been synthesized on the basis of the outputof piezoelectric stacks response to sine excitation signals.After cutting parameters designed, online turning experiments can be conducted toverify the machinability of cutting device and the effectivity of preceding processingscheme. According to the results of contrast experiments about different manufacturingmethods, vibration frequencies, feed rates, elliptical track postures and workpiecematerials, conclusions has been drawn that the regular distribution of machined surfacemicrostructure can be effectively weaken by elliptical vibration turning with randomizedamplitude, compared with traditional turning and conventional elliptical vibrationturning; irregular microstructured surfaces with higher quality can be acquired byappropriately increasing the elliptical vibration frequency, reducing the feed rate, orusing horizontal elliptical track posture.