The Variation of Surface Shape in the Gas Jet Forming

Abstract

This study investigated the the gas jet forming process for optical aspherical mirror blanks. The trend of the influence of the gas jet parameters on the surface shape of the mirror blanks was inferred by analysing the variation in the morphology of the gas jet stream. Based on the theoretical analysis, the inference was verified by numerical simulation. The experimental results were compared with the simulation predictions, and it was found that the average prediction deviation for the diameter was 1.07 mm, while the average prediction deviation for the principal curvature was 0.03665 mm−1, which is challenging to correct in simulation. Therefore, we developed a dimensionless prediction model of the surface curvature and surface diameter of the mirror blanks by considering the jet parameters using experimental data. The model’s average prediction error for the surface diameter of the formed surface was 0.3192 mm, and the average prediction error of the principal curvature for the formed surface was 0.00269 mm−1.