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Atmospheric Pressure Plasma Jet (APPJ) is a promising technology for precision machining of optical elements due to its high efficiency, free damage and lower cost, it has been developed as a promising technique for advanced optical fabrication in high energy laser systems, space optics and large telescope projects. Nowadays the challenge faced by the plasma technology application is the effect of plasma temperature on removal rate and surface accuracy. In the plasma processing, the plasma itself not only acts as the supplier of reactive species but also acts as a local heat source. Based on the pure chemical reaction mechanism the material removal rate, the removal rate strongly depends on the workpiece surface temperature, and the temperature fluctuations originating from the plasma jet lead to a nonlinear etching behavior. The thermal effect caused by high temperature and high enthalpy of plasma jet restricts the high-precision machining of optical components. In this paper the heat transfer process between plasma jet and substrate is established and the simulation analysis, experiment research also conducted. Based on the energy balance in the generalized lowtemperature plasma processing, the suitable boundary conditions are selected and the heat transfer model in the jet processing is established. The heat flux density on the surface of the components under different machining conditions is acquired by conducting a steady-state temperature measurement experiment. An iterative method is proposed to fully determine the thermal boundary condition, the heat transfer model between plasma jet and substrate is established. And the heating and removal experimental studies are carried out to verify the proposed heat transfer model and thermal effect on material removal is analyzed for plasma processing.
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