Theory Research And Control On Uniformity Of Electric Field Distribution In Electroforming

Electroforming technology which is based on the principle of electrodeposition makes the metal cation get electrons and reduce into metal atoms,which would deposited on the surface of the cathode,so that the casting can be processed into the desired shape.As a sophisticated manufacturing technology along with its advantages has been a lot of application in the mold manufacturing,aerospace,weapons,precision machinery,micro-mechanical and other industries.But electroforming has low rate of radio deposition,poor uniformity of electroformed layer and other defects,especially the issue of electroformed layer uniformity has severely restricted its development.The non-uniform field distribution in the electroforming solution is an important factor leading to the poor uniformity of electroformed layer.This paper began with the characteristics of electroforming technology and analyzed the theories of electric field in electroforming,then simulated electric field to different shapes of anode based on the finite the method of element analysis,finally put forward a kind of electroforming liquid electric field measurement device based on the traditional three electrode system,and implemented the experimental study of electroformed nickel.The main contents are as follows:(1)Firstly,the research and analysis of the electric field and related theories in the electroforming technology have been made,on the foundation of the theories we analyzed and discussed the main factors that affect the electric field distribution in electroforming solution,obtained result that adjust the distance between each point on the anode and the cathode,which means change the shape of the anode can improve the current density near the cathode.so as to achieve the purpose of improving the distribution of electric field in electroforming solution and around the cathode.(2)Processed anode plate into a semicircle hollow cylindrical anode by CNC machining,cathode is positioned at its center axis when electroforming,respectively established model of electric field on flat anode and semi-circular hollow cylindrical anode.Under the same condition of current density and the experimental parameters,the simulation and analysis have been carried out by the finite element software of ANSYS,respectively.(3)Developed a measuring apparatus based on a three-electrode system to measure the distribution of electric field in electroforming solution,including distribution of measuring point,selection of the electrode,electroforming tank and fluid.Under the same condition of current density and the experimental parameters,respectively electroforming experiments have been conducted on the anode plate and the semicircular hollow cylindrical anode,using this measuring apparatus to obtain the spatial distribution of the electric field in the electroforming solution,and the experimental results were compared and analyzed.Ratio of maximum to minimum value of electric field around the cathode is indicated by the simulation results,using of semi-circular hollow cylindrical anode can improve the uniformity of the electric field distribution.Electroforming experimental results using the above electroforming solution electric field measurement methods have confirmed the effectiveness of the electric field measurement method.It can make the distribution of the space field in the electroforming solution and electric field around the cathode more uniform than the anode plate,which can improve the microstructure of electroforming devices and the uniformity of electroformed surface layer.