The Development And Application Of Ultrasonic Slotting Longitudinal And Bending Vibration Tool For Nomex Honeycomb And Ultrasonic Power Supply

Nomex honeycomb composite is widely used in the field of aerospace because of its excellent properties,such as low density,high specific strength,impact resistance and corrosion resistance.There are many processing problems in Nomex honeycomb core's practical application process due to its unique structure and mechanical properties.In recent years,ultrasonic machining method has greatly improved the machining quality of Nomex honeycomb core,and can effectively reduce the cutting force.It has the advantages of high machining efficiency and accuracy,and environment-friendly processing.However,the special ultrasonic cutting tools need to incline a certain angle when machining complex edge contour of the Nomex honeycomb core.There is interference between tool and material,so the machining capacity is limited.And limited by the length of the tool,the cutting depth is smaller and the machining efficiency is lower.In order to solve the problems in the machining of the edge contour of the Nomex honeycomb core,improve the processing quality and the efficiency,and the processing environment,a new method of ultrasonic slotting Nomex honeycomb core with longitudinal and bending vibration tool is proposed.The main research contents are as follows:According to the ultrasonic vibration theory,the vibration characteristics of the longitudinal and bending vibration tool are analyzed.The modal analysis and harmonic response analysis of the whole ultrasonic vibration unit are carried out.The results show that the vibration of the tool is mainly concentrated on the longitudinal vibration along the axial direction and the lateral vibration along the radial direction.The vibration in the circumferential direction can be ignored.And the influences of the length and diameter of the tool,the angle and the thickness of the tool on the amplitude magnification and the resonance frequency of the whole ultrasonic vibration system are obtained.With the influence of structure,the frequency band of the longitudinal and bending vibration tool is generally narrow,so the frequency response of the ultrasonic power supply is put forward higher requirements.In order to realize the application of the longitudinal and bending vibration tool,the controller module,the inverter driving module and the feedback module of the ultrasonic power supply are redesigned.In order to respond to the resonance frequency of ultrasonic vibration unit rapidly,this paper proposes an algorithm combining the neural network with the PID control.The kinematic law of the longitudinal and bending vibration tool with ultrasonic vibration was analyzed,and the transition mechanism of continuous cutting into intermittent cutting was explained theoretically in ultrasonic cutting.On these basis,ultrasonic slotting tests of Nomex honeycomb core were carried out with this tool,and the influences of the amplitude and feed rate on cutting force and cutting quality were studied.Finally,the research of process plan and tool path generation are carried out.And a optimization method based on ant colony algorithm is proposed,which can effectively reduce the running distance of the spindle,improve the machining efficiency,and enhance the value of the longitudinal and bending vibration tool.