Research On Numerical Control Correction Method Of Ultrasonic Horn Considering The Influence Of Assembly And Local Structure

Ultrasonic cutting technology has advantages of high efficiency,environmental protection and good processing quality in the field of composite material processing.Acoustic vibration module is the core of ultrasonic machining system,whether the resonant frequency and impedance match with the ultrasonic power supply and whether the node is located in the flange midpoint are all the keys to the reliable operation of the ultrasonic vibration system.Due to the influence of the assembly parameters between the acoustic vibration dynamic components,the local structure of the ultrasonic horn,the non-uniformity of materials and the Poisson effect of ultrasonic propagation,the problems such as mismatching between acoustic vibration module and the ultrasonic power source,difficult or mismatched circuit,excessive vibration of flange joints of ultrasonic horn,non-vibration of acoustic vibration module or amplitude not up to the requirements according to that the actual resonant frequency of the ultrasonic horn designed by the general design theory is far lower than the operating frequency,the actual displacement node of the ultrasonic horn deviates from the flange and the impedance of the acoustic vibration module changes.The stability and efficiency of ultrasonic machining system depend on the change of ultrasonic horn.There are problems of low efficiency and uncontrollable precision in the existing trial repairing methods.In this paper,a numerical control correction method of ultrasonic horn considering the influence of assembly and local structure was studied to modify the geometric parameters of ultrasonic horn in the case of one-time clamping,so that the performance parameters can meet the design requirements.The main contents of this paper are as follows:The static and dynamic performance parameters and measurement methods of acoustic vibration components were analyzed and a dynamic performance parameter measurement system was established.Through the static and dynamic parameter measurement experiment,the influence of the assembly parameters between the components of acoustic vibration assembly on the static and dynamic performance was studied and The best assembly parameters were determined,which provides reliable assembly parameters for the modification of ultrasonic horn performance parameters.Based on the one-dimensional longitudinal wave equation,the mechanical four-terminal network parameters with arbitrary section were established,and the performance parameter calculation model of multistage ultrasonic horn with modified parameters was established by using the matrix transmission principle,which provided the theoretical basis for the calculation of modified parameters.A general area function calculation method for the hollow section bar was proposed,The equivalent radius method was used to solve the problem of large deviation of performance parameters of traditional hollow section area function calculation.Consequently,the accuracy of theoretical calculation of performance parameters was improved.,and the finite element simulation verifies the effectiveness of the method and provides a theoretical basis for improving the correction accuracy.Based on four-terminal network parameters and matrix transmission principle for the connecting screws,threaded holes,flanges and tool heads,an equivalent modeling method considering the local structure of ultrasonic horn was proposed,an equivalent model considering the performance parameters of the local structure of the ultrasonic horn was established,and The influence of local structural parameters on the system performance is analyzed.The validity of the equivalent model is verified by finite element simulation,which created for further improving the accuracy of the revised theoretical model.In this paper,a numerical control correction method for ultrasonic horn under the premise of optimum assembly parameters and under the condition of one-time clamping was proposed.Based on the equivalent model considering the local structure and the difference between the actual and theoretical sound velocities,an objective function was established to prevent the amplification times before and after modification.A modified parameter optimization model with the constraints of designing resonant frequency and fixing joints was proposed.SQP algorithm was used to optimize the modified parameters of ultrasonic horn.The numerical control correction system of ultrasonic horn was established,and the numerical control correction of ultrasonic horn was realized.The validity and efficiency of the modified models were verified by experiments.