Two ways to produce the low e tempered glass and their characteristics.

Their are two ways to produce the tempered low e glass. The first way is to coat film on the tempered glass, the second way is to coat film first, then tempered the glass with coated film. The two ways their own characteristics.

For the way to coat film first, then tempered. This need the film to be intact under high temperature. By this way, the advantage is that the production efficiency of low e glass is high, but cost is lower. The low e glass could be sold to the deep processed factory to be tempered and make insulated glass, it also can be made into bent tempered low e glass and curved low e glass with double curved surface, which used in the glass curtain wall.
But the disadvantage for this way is that the film which can keep intact under high temperature is not much. And in the tempered process, the low e glass could reflect the heat radiation, then the two sides of low e glass is easily to have different flatness because the uneven heating. The appearance of the two surface maybe different because of the high temperature made the film layer have chemical reaction, so need the rich experience and good technology.

For the way to tempered glass first, then coat film. The advantages is that the film needn’t under high temperature which is higher than 500℃, and the design for the layer structure and raw materials of film is easy, just to consider the glass color, the light transmittance, the reflectivity and the thermal performance, no need to consider the effect from the high temperature to the film. By this way, more different tempered low e glass can be produced, with good optical and thermal performance, and the flatness is better.
The disadvantages is that need the factory with strong comprehensive capacity, normally the coating process, tempering process, and other process are finished in one plant. It belongs high-end custom made production, and suitable for the glass curtain wall and high-end windows and doors. And this way couldn’t be used to produce the bent low e tempered glass.