Household appliances have very stringent shape requirements, and some of them are even more stringent than those of automobile boards. Because the external panel of household appliances is directly used after simple bending forming in general, most of
the surface used is flat, so the bad shape of the external panel of household appliances will directly affect the shape of the product and the reflection of the plane. For example, many side panels of refrigerators are U-shaped, that is, the side
panels of refrigerators and the top panels of refrigerators are connected together. The length of the plate is more than 3m, and the thickness of the side panels of refrigerators is generally 0.40-0.45mm. The steel plate is long and thin, which requires
strict shape. Electrical appliances manufacturers require that the irregularity of the steel plates of the refrigerator panel and the side panel of the refrigerator should not exceed 2 mm for every 2,000 mm wave height.
In addition, some functional parts also require more stringent shape, such as fingerprint-resistant backplane used to make LCD backlight module, which supports the weight of backlight module, improves the rigidity of backlight module, and provides good heat dissipation, while playing the role of auxiliary reflection. If the back panel of the display is deformed, the rigidity of the backlight module will be reduced, especially the reflection angle of light will be greatly affected, and the reflector will also be deformed, which will make the reflector unable to fully reflect the light to the guide plate.
Surface defect. Passivation treatment of household appliances is generally used as non-visual parts, with relatively low surface quality requirements, allowing for slight hand-feeling defects such as zinc ash, zinc slag, scratches, inclusions and visual color difference; spraying or color-coated household appliances are generally used for visible external panels, which require higher surface quality, but due to the fact that The thickness of the coatings is different, so the requirements for surface defects are different. Among them, the coating thickness of sprayed household appliances board is 60-80 micron, and the coating thickness of color coated board is 18-28 micron. Because of the thick coating, the sprayed surface can partly cover up the defects, while the thin coating on the surface of the color coated plate can magnify the surface defects, so the requirements for the surface defects of the color coated plate are higher than that of the sprayed plate.
Color coated sheets are generally used to manufacture household appliances with high surface quality requirements such as refrigerators and washing machines. No surface defects affecting their use and appearance are allowed. Taking the refrigerator panel as an example, the refrigerator panel is usually a high-brightness surface. Whether it is a color laminated refrigerator panel or a color pre-coated refrigerator panel, the requirements for the surface quality of the substrate are very high. Any concave and convex defects such as roll prints and indentations on the substrate will be magnified after coating or color coating, which will affect the surface quality of the finished product. For example, a color painting factory stipulates that the particle defects of color pre-coated refrigerator panel are as follows: the particle defects with density less than 1 grain/cm2 and diameter less than 0.2mm are allowed; the particle points with diameter less than 0.5mm are allowed to exist at most 5; and the particle points with diameter greater than 0.8mm are not allowed to exist.