Research On Ultrasonic Assisted Electrochemical Milling/Grinding Of SLMed Hastelloy X Parts

As a new rapid prototyping technology,selective laser melting(SLM)can break through the limitations of traditional manufacturing process and produce components with complex shape and excellent performance.Due to the limitation of efficiency and accuracy,subsequent processing is often required for material removal and improvement of accuracy and surface quality.In this subject,a processing technology combining ultrasonic assisted electrochemical milling(UAECM)of tube electrode and ultrasonic assisted electrochemical grinding(UAECG)is proposed to post-process SLM parts,which makes material removal process more efficient and precise.The main research contents are as follows:(1)In order to prove the superior mechanical properties and practicability of Hastelloy X alloy fabricated by SLM,the parts were fabricated by SLM.Then,solution heat treatment was carried out,and its mechanical properties were tested.The reasons for mechanical properties changes were explained from the micro perspective by microscopic morphology observation and EBSD analysis.The electrochemical characteristics of SLMed Hastelloy X parts before and after solution heat treatment were studied.It is proved that the material has excellent corrosion resistance and provides relevant theoretical and parameter support for processing process and Simulation in subsequent research.(2)The mathematical model of ultrasonic assisted electrochemical grinding was established,and the influence laws of processing parameters on machining accuracy and surface roughness were studied.The FEM simulation software was used to simulate the electrochemical milling of the tube electrode,and the influence of the insulation of the side wall of the tube electrode on the machining accuracy and the law of the influence of the ultrasonic vibration on the pressure of the flow field in the machining gap are analyzed.Then electrochemical composite machining experimental platform was established according to the process test requirements.(3)Ultrasonic assisted tube electrode electrochemical milling technology was used to carry out experimental research on machining technology of SLMed Hastelloy X parts after solution heat treatment.In order to ensure its machining accuracy and machining stability,a series of process experiments were carried out,including the selection of feeding mode,the influence of tube electrode side wall insulation treatment on machining accuracy,the influence of the ratio of electrolyte pressure and immersion depth,ultrasonic amplitude on the machining stability.Through the orthogonal test,the influence weight of various factors on ultrascnic assisted tube electrode electrochemical milling and the machining parameters with excellent machining stability and machining accuracy are obtained,which creates the prerequisite for the subsequent ultrasonic assisted electrochemical grinding.Finally,the typical structures with machining depth of 2mm and 4.2mm are obtained by optimizing the machining parameters.(4)The experiment of ultrasonic assisted electrochemical grinding of pre groove with abrasive electrode was carried out to study the effects of electrical parameters,feed speed,rotation speed and ultrasonic amplitude on machining efficiency,machining accuracy and machining surface quality.The optimized parameters obtained from the process test are used to process the typical structure,and the final width is 1120±10μm,the surface roughness is from Sal.880μm is reduced to Sa0.209μm compared with the pre groove obtained by ultrasonic assisted tube electrode electrochemical milling,The processing quality has been significantly improved.