A brief introduction to the polishing process of optical lens

Through long experience accumulation, the astronomical telescope manufacturer found that the surface of the optical lens has a crack layer of about 2 - 3M thick on the surface of the lapping liquid, and the method of eliminating this crack is to be polished.

Like polishing and polishing mechanism, the material used is different from the polishing liquid (slurry). The material used for polishing is cloth, polyurethane and pitch. The high precision polishing surface is usually achieved, and the most commonly used material is the high polished asphalt.

The use of bitumen to polish it is by using the fine surface of the bitumen to drive the polishing liquid to grind the surface of the lens, melt the glass, melt the rough vertex and fill the cracked bottom, gradually removing the cracks. At present, the polishing powder used for polishing glass lenses is based on cerium oxide (CeO2). The proportions of the polishing liquid are different depending on the polishing period of the lens. Generally, the high concentration of the polishing liquid is used when the polishing stage is combined with the polishing die. After the surface of the telescope lens is bright, the polishing solution is used to avoid the concentration of the polishing solution. The appearance of the orange peel (the surface atomization of the lens) is produced without the mirror surface.

The polishing and grinding mechanisms are the same. Besides polishing tools and working fluids, polishing requires more stringent environmental conditions than grinding. General polishing should pay attention to the following matters: polishing asphalt surface and polishing liquid can not be impurities, otherwise it will cause mirror scratches. Polishing the surface of the asphalt should be consistent with the surface of the lens, otherwise it will produce a beating when polishing, thus biting the polishing powder and scratching the surface of the lens.

Before polishing, it is necessary to determine whether the surface of the lens is scratched or pierced after grinding. Whether the size and material of the polishing tool are appropriate. Whether the soft hardness and thickness of the asphalt are appropriate. During polishing, we must pay attention to the condition and accuracy check of the lens surface. The inspection of the defect on the surface of the lens, because the detection process is judged by the individual vision and method, so the inspector should have a deep understanding of the specifications of the scraps and sand holes, and often compare the standard samples of the scratches and sand holes to ensure the correctness of the inspection.