Basic Research On Additive Manufacturing Technology Based On The Fusion Of Ultrasonic Welding And EDM

Metal waveguide device is an important part of radio astronomical telescopes.Because of its good mechanical properties,copper is used for the processing of this waveguide device.The processing of micrometer-scale copper waveguide holes and coupling holes is a key technical difficulty.Ultrasonic additive technology It is an effective processing method.In this paper,the basic research on the related processes is carried out:firstly,the ultrasonic welding technology is used to weld the copper sheet in layers to obtain the optimal ultrasonic welding process of copper and explore the mechanism of ultrasonic welding of copper.On the basis of welding,micro-EDM is used to process internal signal holes and coupling holes,and ultrasonic assistance is introduced to improve the efficiency of electrical discharge machining.Repeat the above steps until the component is processed.Related research results are as follows:The tensile test of the ultrasonic welding joint of copper shows that the maximum tensile strength of the joint is up to 1498.7N when the welding time is 600ms,the welding power is 1400W and the welding pressure is 0.4Mpa.Single factor analysis was used to analyze the significance of three main parameters on the joint strength:the welding pressure had the greatest influence on the joint strength,and the welding power and welding time had no significant influence.Analyze the significant law of the influence of the interaction between different process parameters on the strength of the joint.The effect of the interaction of any two parameters on the strength of the joint is higher than that of a single parameter.Therefore,in the ultrasonic welding experiment of copper:the interaction between different parameters is realized The key to connection.And the interaction of different welding parameters:interaction of welding time and welding pressure>interaction of welding power and welding pressure>interaction of welding time and welding power.The analysis of the macroscopic morphology of the welded joint shows that the saw tooth mechanical chiming appears in the early stage of ultrasonic welding of copper,and the mechanical chiming disappears with the increase of welding process parameters.The microstructure analysis shows that there is grain refinement along the metal interface in the area with good metallurgical bonding,and it can be inferred that during the ultrasonic welding of copper,some copper melting occurs in the central area of the welding spot.Study on ultrasonic welding process of copper:atomic diffusion occurs at the interface of copper ultrasonic welding joint during the connection process,and when the welding pressure is large,the atomic diffusion is sufficient and the joint quality is better.The mechanism of copper electric discharge machining was explored and related mathematical models were established.The effects of pulse width,pulse interval,pulse current,extreme voltage,discharge gap and other parameters on pulse energy and discharge machining process were studied.According to this,four sets of pure tungsten electrodes were developed for discharge processing of red copper waveguides:C005,C004,C923 and C915.The discharge machining of copper after ultrasonic welding focuses on the machining accuracy,taking into account the discharge efficiency and electrode loss factors.The C923 discharge standard is established as the best experimental program for copper discharge machining.Under the condition of better parameters and standard,ultrasonic layer welding is carried out and the internal contour is processed by discharge on the basis of welding.The local vibration signal void,receiving signal hole and coupling hole are processed by repeating the above steps for many times.Comparing the accuracy of the holes obtained after fusion machining and precision milling,the results show that the hole groove Angle error and planeness error of C923 discharge calibration are much smaller than that of precision milling,which verifies the superiority of edm under micron scale machining precision.The real-time compensation of tool electrode loss during discharge machining was carried out,and the positive effect of electrode loss compensation on machining precision control and improvement was explored.In order to improve the discharge machining efficiency on the basis of ensuring the machining accuracy,an ultrasonic auxiliary module was introduced.A set of simple ultrasonic module was designed,including ultrasonic generator,ultrasonic transducer and clamping protection device(sleeve clamping part,protective shell and connecting part).Under the action of ultrasonic vibration,the discharge processing of red copper was carried out,and the ordinary electric discharge machining was set as a control experiment.The results show that whether ultrasonic vibration has no significant effect on the efficiency of electrical discharge machining..This is inconsistent with related research rules.According to this analysis,the reasons for this result are as follows:the ultrasonic vibration amplitude is small,and the poor connection between the electrode and the transducer makes the displacement transferred to the end face of the tool electrode too small to improve the discharge gap.The small ultrasonic vibration displacement cannot affect the stable discharge point arc,nor is it enough to remove the debris deposited between the two stages,so as not to reduce the arc discharge of the debris or the short-circuit caused by the debris.In order to verify the cause analysis and improve the ultrasonic module to improve the discharge machining efficiency,a horn matching with the ultrasonic transducer was designed to amplify the ultrasonic vibration amplitude.The designed horn was solved theoretically and simulated by ANSYS software.The modal analysis shows that under the expected value close to the rated frequency of 20KHz,the natural frequency value of the 19504Hz modal vibration mode is longitudinal vibration in the X-axis direction,which meets the design requirements.The harmonic response analysis under this frequency value shows that the amplitude amplification coefficient of the designed lug is 2.75.The 2.75-fold amplitude amplification and the traditional dominant connection(ultrasonic transducer is connected to the horn and the horn is connected to the tool electrode)make up for the vibration reduction caused by the small amplitude and the direct connection between the tool electrode and the transducer,which should be able to improve the discharge processing efficiency of copper under the action of ultrasonic vibration.