Study On The Design And Fabrication Of Solid Micro Thruster Based On MEMS

With the improvement and development of the micro aerocraft technology, more and more advanced requires are brought forward for micro propulsion system. As it has so many advantages such as small size, low cost, low power consumption, high reliability and no pollution, micro thruster based on micro-electro-mechanical system (MEMS) has obtained more and more recognitions in recent years. In this paper, a three-layer solid micro thruster is designed and fabricated through the study of micro machining technology. The main contents of the paper are as follows:1. Different kinds of micro propulsion system are summarized in home and abroad. All kinds of advantages and disadvantages are analyzed and compared. Based on this, the project about micro thruster is proposed.2. A solid micro thruster is designed. It contains top layer, middle layer and bottom layer, which are ignition circuit layer, chamber layer and diaphragm layer respectively. Theoretically this thruster should have the advantage of low ignition power, low ignition voltage and high thrust.3. The technology of depositing Cr film is studied by the method of direct current sputtering. Process parameters related to the film sputtering velocity are discussed. Relations are found between the etching rate and different process parameters when SiO2 thin films are etched in an Inductively Coupled Plasma (ICP) etching equipment. Process parameters related to the eroding of Cr and Si are studied through experiments, and some conclusions are obtained at the same time.4. A process flow composed of sputtering, lithography, eroding and ICP etching is planned to make the solid micro thruster successfully. Experiments have shown that the process flow is feasible, and it has high maneuverability and high success ratio.5. Some ignition experiments are achieved about the micro thruster which has been factured and the ignition voltage and power are obtained. Based on the knowledge of mechanics and calorifics such as the rocket engine theory, heat effect theory, and together with ANSYS simulation analysis, the power needed in successful ignition and the thrust performances are deduced. What's more, the thrust and impulse of the micro thruster are tested by an electronic analysis balance.Results of the research and experiments in this paper are beneficial to design and fabrication of micro thruster. The micro machining technology can also be used for other MEMS products.