【作者】 胡涛；

【导师】 傅波；

【作者基本信息】 四川大学 ， 机械工程， 2021， 硕士

【摘要】 随着现代工业技术的快速发展,各种新结构、新材料的复杂零部件不断出现,相应的加工需求也在不断提高。而分布在航天航空、电子工业、汽车制造等各行业的微小孔加工,一直都是重点制造技术难题,深受国内外各界重视。射流电解加工是微小孔加工的主要方式之一,但也存在定域性较弱、水跃现象、加工不够稳定等不足。考虑到超声波具有方向性、能量集中、穿透性好等优点,在传播过程中存在空化效应、热效应、机械效应等理化效应,本文将射流电解加工与超声加工技术相结合,提出了浸入式超声辅助射流电解加工的方法。本文的主要研究内容如下:(1)介绍了复合电解加工技术,重点阐述了射流电解加工及射流电解复合加工、超声加工技术的研究现状,对射流电解技术的原理和超声相关理论进行分析。基于相关的理论研究,提出了浸入式超声辅助射流电解加工的方法,并设计相应的结构方案。(2)利用传输矩阵法和半波长原理设计了20k Hz超声振动系统,根据超声振动系统的工作要求设计浸入式超声辅助射流电解加工系统及其相应的连接密封形式。(3)在有限元软件ANSYS Workbench中对设计的超声振动系统三维模型进行模态分析及优化,使其谐振频率接近设计频率,优化后的超声振子频率为19.952k Hz。对优化后的超声振子进行谐响应分析,确保超声振子的输出振幅满足加工需求。(4)利用有限元分析软件COMSOL对电解腔室进行声场分析并进行相应的结构优化,流场分析得到电解腔室的流动情况,模拟超声的作用得到电解腔室的流动变化。利用COMSOL对加工间隙的电场、流场、几何变形进行多物理场耦合分析,得到射流电解加工下工件的蚀除规律。(5)对设计加工的浸入式超声辅助射流电解加工系统进行装配并搭建实验平台,通过阻抗测试验证超声振动系统设计的合理性,并探究超声对电解液电导率的影响;对装配好的实验平台进行预实验,验证整个系统的可靠性和合理性;控制单一变量进行超声辅助射流电解加工实验,利用超景深显微镜对加工小孔表面进行检测,得到实验结果。实验结果表明:浸入式超声辅助射流电解加工系统可以有效提高射流液束的流动性,改善水跃现象,加工稳定,可缩小加工间隙,加工孔径明显缩小,提升深径比,增强加工的定域性,提高加工质量。更多还原

【Abstract】 With the rapid development of modern industrial technology,complex parts with new structures and new materials continue to appear,and the corresponding processing requirements are constantly increasing.The processing of micro-holes in various industries such as aerospace,electronics,and automobile manufacturing has always been a key manufacturing technical problem,and has been highly valued by all walks of life at home and abroad.Jet electrochemical machining is one of the main methods of micro-hole machining,but there are also disadvantages such as weak localization,hydraulic jump,and insufficient machining stability.Considering that ultrasonic has the advantages of directivity,energy concentration,and good penetration,and physical and chemical effects such as cavitation,thermal,and mechanical effects during the propagation process,this thesis combines jet electrochemical machining with ultrasonic machining technology,and proposes a method of immersed ultrasonicassisted jet electrochemical machining system.The main research contents of this thesis are as follows:(1)Introduce the composite electrochemical machining technology,focusing on the research status of jet electrochemical machining,jet electrochemical composite machining,and ultrasonic machining,and analyze the principle of jet electrochemical technology and related ultrasonic theories.Based on the related theoretical research,the method of immersed ultrasonic-assisted jet electrochemical machining is proposed,and the corresponding structural scheme is designed.(2)The 20 k Hz ultrasonic vibration system is designed by using the transmission matrix method and the half-wavelength principle.According to the working requirements of the ultrasonic vibration system,the immersed ultrasonic-assisted jet electrochemical machining system and its corresponding connection and sealing form are designed.(3)Modal analysis and optimization on the designed three-dimensional model of ultrasonic vibration system are performed by using ANSYS Workbench,so that its resonance frequency is close to the design frequency,and the optimized ultrasonic vibrator frequency is 19.952 k Hz.The harmonic response analysis of the optimized ultrasonic vibrator is carried out to ensure that the output amplitude of the ultrasonic vibrator meets the processing requirements.(4)By using the finite element analysis software COMSOL,the acoustic field of the electrolysis chamber is analyzed and the corresponding structure is optimized.The flow field analysis obtains the flow of the electrolysis chamber,and simulates the effect of ultrasound to obtain the flow change of the electrolysis chamber.Using COMSOL to conduct multi-physics coupling analysis on the electric field,flow field and geometric deformation of the machining gap,the erosion rule of the workpiece under jet electrochemical machining is obtained.(5)The designed and processed immersed ultrasonic-assisted jet electrochemical machining system is assembled to build an experimental platform,and the rationality of the ultrasonic vibration system design is verified through impedance testing.The effect of ultrasound on the conductivity of the electrolyte is explored.The preexperiments are carried out to verify the reliability and rationality of the entire system.The ultrasonic-assisted jet electrochemical machining experiment is conducted according to a single variable,and an ultra-depth-of-field microscope is used to detect the surface of the processed small hole,and the experimental results are obtained.The experimental results show that the immersion ultrasonic assisted jet electrochemical machining system can effectively improve the fluidity of the jet liquid beam,improve the hydraulic jump phenomenon,make the processing stable,reduce the processing gap,significantly reduce the processing aperture,increase the depth-todiameter ratio,and enhance the localization of processing Performance and improve processing quality.更多还原