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The overall manufacturing process of laminated glass should be divided into 12 processes, the process is as follows:
1, cut a large piece: The original glass must be opened into a blank. The blank glass is usually 30-50mm larger than the actual size to facilitate the surrounding edge. When cutting the blank, pay attention to the direction of the shower of the glass, and ensure that the two glasses are in the direction of the vertical shower to ensure the driver's visual distortion is less and not easy to fatigue.
2, cuttingSince the curved laminated glass is formed by bending the inner and outer two layers of glass together, the inner sheet of the glass is generally shorter and shorter than the outer sheet, depending on the curvature of the glass and the spherical size. Whether it is CNC cutting or pattern cutting, it is necessary to distinguish the size of the glass, and then pair it into the bending process. The cutting oil must also be used correctly during cutting to control the cutting pressure and the depth of the knife.
The use of cutting oil is difficult to prevent hem, because the moisture in the air penetrates into the knife edge to isolate the knife edge from the air. In order to ensure the cutting quality (no edged glass chips or notches, the edge is transparent, continuous, uniform), it is necessary to control the cutting pressure not to be too large or too small (depending on the thickness of the cutting product), and the strength of the cutter wheel and the selected The angle of the cutter wheel is also related. Usually, the cutter wheel with a=136° for 2m/m glass and a=150° for 4m/m. The cutting pressure of the interlayer 2 m/m glass is generally between 0.18 and 0.2 MPA. If the depth of the knife is too deep, the glass will be broken. If it is too shallow, the glass will not be cut.
3, edging: The purpose is to remove some small cracks in addition to the fast mouth and not cut the hand. Generally, the laminated glass only needs to be inverted. As the process requirements are higher, many exposed glass appear, and the laminated glass also begins to use fine grinding edges. Such as A6, B5 and so on.
4, washing and drying: After the edging, the glass should be cleaned of dust, oil and impurities on the surface to ensure good adhesion. Washing is an important part of the transparency and yield control of the sandwich process.
5, dustingIn order to prevent the two glass laminate layers from sticking during the bending process, a thin powder is usually sprayed on the surface of the glass, and silica having a diameter of 0.8 μm is usually used.
6, drying the bend: The bending process determines the shape of the glass, isLaminated glassThe key processes of production. Bake bending is a laminated glass semi-finished product which is bent into various shapes by bending and is annealed. It is generally carried out in a bending furnace. The baking bending furnace is generally divided into upper and lower layers. The upper layer is used for preheating, bending forming, and lower layer. Used for annealing and cooling, to mold. Note: The transmission must be smooth to prevent the misalignment of the two sheets of laminated glass. Because of the requirements of the laminated glass user, there must be a compressive stress greater than 4N in the periphery. The middle part must be annealed, and the tensile stress value is less than 7N. If the tensile stress is at the center part. Too large, the glass will break when installed.
7, clear powder: When the glass and PVB are combined, the powder sprayed on both sides of the glass must be removed, including the edge of the glass, so that no bubbles or pittings are generated.
8, PVB film: The PVB is uniformly heated while being stretched into a fan shape, and then uniformly cooled to "freeze" the curved shape of the PVB into a curved shape.
9, humidity controlThe moisture content of PVB has a great influence on the performance of laminated glass. The higher the water content, the smaller the adhesion between it and the glass. On the contrary, the water rate is too low, the adhesion is strong, and the penetration resistance is high. The smaller.
10, splicingPut the glass that needs to be inserted into the PVB film into the laminating machine, suck up the upper piece with a vacuum suction cup, remove it, put it into the PVB film, put down the upper piece of glass, and cut off the excess PVB film edge material. Because the two sides of the float glass are different, one side is in contact with the tin in the tin bath during production, and one side is in contact with ammonia. We are often referred to as tin and air. The adhesion between the air surface of the glass and the P V B is stronger than that between the tin surface and the PVB, so that the air surface of the inner sheet is facing inward during production, and the air surface of the inner sheet is superposed outward. This will ensure that the two air faces are in contact with the PVB.
11, initial pressure: Generally, the pressure roller method or the pressure reduction method is adopted.
Purpose: To remove air from the sandwiched glass and the interlayer as much as possible and to seal the surrounding to prevent hot kerosene or bubbles from immersing in the glass during the high pressure process. The glass and the film are initially bonded together, and at high pressure, there is no staggering between the layers, so that moisture does not penetrate into the interior of the laminated glass.
12, high pressure: Although the glass laminate is basically glued after the initial pressure, there is still some gas that cannot be driven away at the initial pressure. The firmness of the glue is not strong. The bubbles in the laminate should be completely discharged and firmly bonded. Applying a relatively uniform pressure and a higher temperature required to soften the film, it is heated and pressurized in the autoclave to completely remove the gas and completely bond the glass to the PVB film, which is transparent. Huashang BSG Wang Gong said that this is also a key link in automotive glass production.
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