Study On Ultrasonic Elliptic Vibration Deep-hole Boring Technology For High-strength Steel 18Cr2Ni4WA

Some areas such as aerospace often need deep-bore parts for specialized purposes,while deep-hole processing is still a problem,especially when it comes to difficult-to-cut materials.In traditional deep hole boring,the chatter occurs easily because of the great ratio of length and diameter of boring bar and poor rigidity of the cutting system,which severely affects the machining accuracy and surface quality.The cutting can lower the cutting force,improve the stability of the cutting system and provide the possibility for improving the process of deep-hole machine.In this paper A study on ultrasonic elliptical vibration deep-hole boring technology for high-strenght steel 18Cr2Ni4 WA is conducted.ultrasonic elliptical vibration cutting was applied to deep-hole boring to reduce the chatter of the boring process and to improve the machining surface quality.The basic principles of different kinds of ultrasonic vibration cutting are analyzed first.Finite element software ABAQUS/Explicit is adopted to analyze the process of different cutting ways,such as the traditional cutting,ultrasonic vibration cutting and two-dimensional ultrasonic vibration cuttings.The results of simulation show the cutting forces of different ways of cutting and cutting process.Finite element method is used to design a single ultrasonic elliptical vibration deep-hole boring device.It can bore the deep hole,whose minimum diameter is 17 mm and maximum length to diameter ratio is up to 20.The device is driven by the longitudinal transducer and works with the bending vibration mode.The bending vibration and longitudinal vibration are coupled into the elliptical trajectory at the tip of the tool.The structure is optimized by modal analysis and based on mode analysis,harmonic response analysis and transient analysis are completed by means of finite element analysis,and output amplitude-frequency curve of the device and the action of the cutting tool trajectory are found,which justify preliminary the design method and the rationality of the device structure.The frequency response of the ultrasonic elliptic vibration deep-hole boring device is measured with impedance analyzer,and the resonance frequency is 22.43 KHz.The relationship between the output amplitude and the excitation voltage of the boring bar is tested by laser displacement sensor.Relying on the design of the ultrasonic elliptical vibration deep-hole boring device,experimental researches on cutting force,cutting stability,surface roughness and chip-breaking effect of ultrasonic elliptical vibration deep-hole boring are conducted and the 18Cr2Ni4 WA alloy steel is utilized in this paper.Experimental results verified ultrasonic elliptical vibration deep-hole boring can lower the cutting force,about 30% that of ordinary cutting,reduce the system chatter,achieve a 26% improvement of surface roughness and shorter length of chips,which give it an advantage over the traditional cutting.The effect of ultrasonic amplitude and other cutting parameter on cutting force,system stability and surface roughness in ultrasonic elliptical vibration deep-hole boring processing is study by experiments.The results of the experiment provide the basis for the optimization of ultrasonic elliptic vibration deep-hole boring process parameters.