Optical glass manufacturing process
In recent years, due to the development and progress of science and technology, the manufacturing process of optical glass, from melting raw materials to preform molding, mostly adopts the consistent operation of automated production methods to improve quality and production volume and reduce costs. Optical glass manufacturers usually focus on the development of new products, the improvement of production technology and efficiency, the improvement of quality, and the reduction of manufacturing costs, etc., without expanding production equipment. Therefore, it often takes several months from receiving an order to shipping. The manufacturing process of optical glass is approximately as follows: 1. Manufacturing melting furnace: There are two types of melting furnaces: clay furnace and platinum furnace. In recent years, small platinum furnaces have been used for optical glass that has infiltrated rare elements to maintain stable quality. 2. Put the optical glass raw materials: after a long period of drying in the melting furnace (especially the clay furnace), put the raw materials according to the special formula and selected materials into the melting furnace, ready to be melted. Three, heating, melting, stirring: heating conditions, depending on the material. However, the various materials must be stirred evenly to achieve homogeneity. Four. Cooling: Give it 'Xu Chill' for a long time. However, the length of time also varies from material to material, which is the most important process to ensure good quality. 5. Splitting the furnace and sorting: Split the clay furnace (Note 4), take out the massive rough embryo and sort it. Six. Inspection, testing, and shaping: check or test each performance item by item to ensure excellent quality. Seven. Cutting and chamfering (trimming): Cut the block rough embryo into small pieces and chamfer according to the purpose and specifications. 8. Embryo forming: After heating and softening the rough embryo, press the embryo to form according to the specifications of the engineering drawing. However, various molds, tools and auxiliary materials must be manufactured or prepared in advance. Nine. Burning: annealing passivation to eliminate internal stress. 10. Test and inspection: Test the optical performance and appearance of the preform. The finished product will become the blank of the downstream industry (optical component manufacturing and processing plant), and after further processing and grinding, it will become an optical component. The gas (gas) generated from the raw materials during melting will remain in the glass like bubbles, which are 'bubbles'. The traces of stirring will also remain in the glass in layers, like stripes, called 'veining'. At present, it is still difficult to melt optical glass that is completely free of 'bubbles' or 'veining'. The yield rate is about 50 to 70%. Unqualified glass can be crushed, returned to the furnace, and remelted. When the optical glass of the same material is not melted in the same batch (furnace), there are some differences (errors) in the optical performance due to the difference of the raw material formula or the manufacturing conditions. Therefore, the manufacturer must add the measured refractive index and Abbe number to the finished product. It is very important for downstream optical component manufacturers to correct their optical system design values u200bu200bbased on this value if necessary.