Jiaoteng Ding

The development of high precision carbon fiber composite mirror

Due to low density, high stiffness, low thermal expansion coefficient, duplicate molding, etc., carbon fiber reinforced polymer (CFRP) is one of the potential materials of the optical mirror. The process developed for Φ300mm high precision CFRP mirror described in this paper. A placement tool used to improve laying accuracy up to ± 0.1°.A special reinforced cell structure designed to increase rigidity and thermal stability. Optical replication process adopted for surface modification of the carbon fiber composite mirror blank. Finally, surface accuracy RMS of Φ300mm CFRP mirror is 0.22μm, surface roughness Ra is about 2nm, and the thermal stability can achieve 13nm /°C from the test result. The research content is of some reference value in the infrared as well as visible light applications.

The lightweight structure design of a CFRP mirror

The advantage of Carbon Fiber Reinforced Polymer (CFRP) is obvious as a common space material for low density, low thermal expansion coefficient and high specific stiffness characteristics, it is the ideal material choice for space optical reflector. Mirror structure with honeycomb can achieve high rates of lightweight, as well as high specific stiffness. For Φ300mm CFRP mirror, accounting of the actual process properties of CFRP, mirror panels laminated based on thermal stability design, honeycomb fabricated using one innovative inlaying-grafting design method. Finally, lightweight structure design of the CFRP primary mirror completed, the thermal stability result of the Φ300mm CFRP mirror achieved is 10nm°C.

Thermal Stability Analysis and Experimental Study of a New Type of Grid-Reinforced Carbon Fiber Mirror

Due to low density, high specific stiffness, and low thermal expansion, carbon fiber reinforced plastic (CFRP) is one of potential materials for high precise components. For high precise structures such as reflectors and optical mirrors, usually strict thermal stability required. In order to ensure rigidity and thermal deformation resistance, carbon fiber mirrors are usually designed as a grid-reinforced sandwich structure. In order to improve the thermal stability of carbon fiber mirrors, a new type of grid-reinforced sandwich structure design is proposed. Finite element method was used to analyze the thermal deformations of the carbon fiber mirror without manufacturing error and with manufacturing error. In order to overcome the effect of moisture absorption deformation, thermal deformation test of the carbon fiber mirror was performed in a vacuum tank. The test results verify the reliability of the finite element analysis results. For Φ100mm center aperture of the Φ150mm carbon fiber mirror, the test results show that the thermal stability is about 4xa0nm/°C, which is enough for optical mirror application, although “grid effect” existed.

Mirrors fabricated with slightly oxidized C/C composites

Up to now, traditional materials, such as glass, metal and SiC ceramic, gradually begin to be unsatisfied development of the future mirrors. Designable carbon fiber reinforced composites became optimized material for large aperture lightweight mirrors. Carbon/carbon composites exhibit low thermal expansion and no moisture-absorption expansion problem, therefore, they get particular attention in the space reflector field. Ni was always employed as optical layer in the mirror, however, the coating behaved poor bond with substrate and often peeled off during optical processing. In order to solve this problem, slight oxidation was carried on the C/C composites before Ni plated. The Ni coating exhibited stronger coherence and better finish performance. Finally, a 100mm diameter plane mirror was successful fabricated.