Research on the disassembly process of the primary mirror components after the deformation of the glass-ceramic primary mirror

The primary mirror system is the key component of the high-precision optical system, and the surface accuracy of the primary mirror determines the imaging quality of the whole system. When the surface accuracy of the primary mirror decreases, the optical performance of the whole optical system will be seriously affected. At this time, the primary mirror of the primary mirror assembly needs to be disassembled, and the secondary assembly of the primary mirror assembly is carried out until the assembly index is met. <br/><br/> In this paper, the research object is a 98 mm aperture glass-ceramic primary mirror component, which is composed of a glass-ceramic primary mirror and a primary mirror backplate, and the bonding method is central axis epoxy 2216 adhesive. When the surface shape of the primary mirror changes and exceeds the expected result, the primary mirror and the back plate of the primary mirror need to be removed, and the primary mirror needs to be reassembled. Aim at that bonding mode of the primary mirror component, the primary mirror component need to be placed in a hot oven, and the epoxy 2216 adhesive is inactivated by high temperature baking, so that the micro crystalline glass is separate from the back plate of the primary mirror. In the actual operation process, the heating rate of the thermal oven is too fast, and a higher temperature gradient appears on the surface of the primary mirror. Because of the appearance of the higher temperature gradient, the stress distribution of the primary mirror in the glass-ceramic exceeds its tensile strength, resulting in cracks on the surface of the primary mirror in the glass-ceramic. In this paper, combined with the material properties of glass-ceramics, the causes of cracks are analyzed, and according to the analysis results, a safe disassembly process is formulated for the future disassembly of glass-ceramics.