Surface Quality Research On Ultrasonic Cutting Of Nomex Honeycomb By Disc Cutter

As the core material of the honeycomb sandwich structure,the processing accuracy and surface quality of Nomex honeycomb core determine the performance of the sandwich structure.However,due to the weak in-plane stiffness,the honeycomb core is prone to bending during processing.It is easy to find serious defects such as crushing,tearing and deformation in Nomex honeycomb core through traditional processing technology.In recent years,the application of ultrasonic cutting technology has effectively reduced the cutting force during the processing of Nomex honeycomb core,and the surface quality aLso has been improved.The processing parameters of disc cutter in ultrasonic cutting process directly affect the surface quality of the Nomex honeycomb core.Whereas,there are few relevant studies on the surface quality of Nomex honeycomb cores in ultrasonic cutting with disc cutter.The effect of tool vibration on the separation process and surface morphology of Nomex honeycomb cores is unclear.The research on the influence of processing parameters on the surface quality of honeycomb core is not compreheNsive either.Therefore,in this paper,through theoretical analysis and experimental research,the impact of tool vibration on the material separation process and processing morphology is analyzed,and the effect of processing parameters on the surface quality of Nomex honeycomb core is quantitatively studied.The main research contents and conclusioNs are as follows:(1)Based on the kinematics analysis of the disc cutter,the contact process between the cutting blade and the material in a single vibration period was studied.Through the theoretical analysis of the cutting force,the separation process of honeycomb core during convention cutting and ultrasonic cutting were distinguished to study the role of the vibration of cutting blade.On this basis,the ultrasonic cutting test of honeycomb paper was designed and completed.Combined with the theoretical analysis of cutting force and the observation of cutting morphology,the microscopic cutting morphology of honeycomb material during ultrasonic cutting was clarified,and the reasoNs for the cutting morphology were analyzed.Theoretical analysis and experimental results show that the ultrasonic vibration of cutting blade accelerates the generation of initial crack before the tool cuts into the material.After that,the impact of the cutting blade on the chips and the processed surface is helpful for the propagation of the crack.The cutting morphology of aramid fiber is improved,but the phenolic resin breaks evenly,and the width of the honeycomb wall becomes larger.(2)The Nomex honeycomb core ultrasonic cutting tests were designed.By observing the cutting morphology of Nomex honeycomb core,the increasing width and tearing defect of honeycomb wall,which has a great influence on the surface quality of Nomex honeycomb core,were selected as the characteristic morphology.The width increments ΔWs,the tearing number Ns and the average of tearing length Ls of honeycomb wall were selected as the characterization parameters of the surface quality.(3)Through the selected characterization parameters,the effects of cutting parameters on the surface quality of Nomex honeycomb core were quantitatively analyzed.The test results show that ultrasonic cutting can improve the surface quality,and a great surface quality can be obtained when the ultrasonic amplitude is in the range of 25 μm-35 μm.Under the same ultrasonic amplitude,the tearing defect reduced with the increasing of cutting speed or decreasing of the feeding speed.The inclination angle of the disc cutter can improve the width of honeycomb wall,but the excessive inclination angle will significantly increase the number of tearing defects.