According to the industry chain downstream to classification, it can be divided into raw materials - CCL - Printed Circuit Board - electronic products application, the simple relation is expressed as: glass fiber cloth, glass fiber cloth CCL is one of the raw materials made of glass fiber yarns, accounting for about 40% of the cost of copper clad laminate (plate) and 25% (sheet). Glass fiber yarn is made by silica sand and other raw materials in the kiln calcined into liquid, pulled into a very fine glass fiber through the tiny alloy nozzle, then the root tangle into hundreds of glass fiber glass fiber yarn. Kiln construction needs huge investment, generally needs hundreds of millions of funds, and once the ignition must be 24 hours uninterrupted production, enter, exit cost is huge. The production of glass fiber cloth is similar to that of weaving enterprises. It can control the capacity and quality by controlling the speed of rotation, and the specifications are relatively single and stable. There has been little change in specifications since the second world war.