Research On Key Technologies For Gold Micro Parts Fabricated By Electroforming

The application of micro parts in the aerospace industry, scientific research is becoming more and more widespread. Because of good ductility, micro parts are difficult to machine with traditional machining method. As a low‐cost manufacturing micro‐parts technology, The metal micro parts with complex shape can be manufactured easily by UV‐LIGA technology. So UV‐LIGA technology based on SU‐8photoresist is introduced to fabricate gold micro parts. The following works have been done:（1） Parameters have been researched and optimized based on the SU‐8photoresist （300microns）. The processes of spinning, soft baking and PEB have been researched. The parameters have been optimized and the problems have been solved. The influence of exposure energy and developing time base on SU‐8photoresist to line width have been researched. The experiment is conducted to optimize the parameters.（2） Electroforming process of pure gold micro parts is researched by using forward flushing fluid. The effect of liquid outlet shape, current density, velocity, distance between anode and cathode to surface quality of pure gold micro parts are studied. The optimum parameters of current density, electroforming time are chosen. Optimizing parameters of the best velocity and distance between anode and cathode are acquired.（3） The law of swelling has been studied. The law of swelling is obtained by researching swelling characteristic of SU‐8photoresist in gold sulfite solution. The law of swelling property while electroforming has been researched by the method of stepwise electroforming. The swelling has been controlled by the sacrificial channel. The optimized design of mask has been obtained.（4） The way of controlling the key dimension of pure gold micro parts has been studied. Controlling the dimensions of the pure gold micro parts by the method of sacrificial channel, over exposure and Line width. With the optimized parameters, the metal micro parts with complex shape can be manufactured easily by UV‐LIGA technology.