Basic Research On Electroforming With Insoluble Anode And Design Of Machine Tool

As a precision nontraditional machining technology, electroforming is used in the manufacture of metallic parts which are difficult to machine using traditional machining methods. In this technique, metal ions are deposited on the cathode surface, and metallic parts with certain shapes and properties can be fabricated precisely.Nowadays, most of electroforming machines produce the work piece by rack and titaniumbasket with the core moulds and anodes hanged in the electroforming bath. However, this device can not meet the requirement of translational motion of cathode and the positioning accuracy. So the electroforming device need to be designed for the large-scale structure. In the electroforming process, insoluble anode does not change the geometric dimensions and can maintain a constant current distribution on the cathode surface. In this paper, the machine tool for the electroforming of large-scale structure and a circulatory system is designed. The main works are presented as follows:(1) The influence of Ni2+ concentration on electroformed nickel by insoluble anode was studied experimentally. The results showed that the concentration of Ni2+ was decreased by 19%, 33.6%, and 54.2% with the current density of 4A/dm2, 8A/dm2, and 12A/dm2,during the nickel electroforming. And the current efficiency decreased to 59.2%, 51%, and 35.9%. Especially at the current density of 8A/dm2 and 12A/dm2, due to the decrease of the concentration of nickel, the grains of the nickel layer refined and micro-hardness increased by 26.5%, 18.6%.(2) To solve the decrease of Ni2+ concentration using insoluble canoed during nickel electroforming, a new circulatory device with a ion exchange membrane was designed, to supply ions to the solution. The results showed that the device can realize the timely supplement of ions during the experiment.(3) According to the characteristics of the large-scale structure and the circulatory system,the electroforming device was designed. The whole equipment includes the pre-processing units, the main electroforming bath, the reservoir, motion control system and the circulatory system.