Things you don't know about the surface technology of aluminum veneerCommon surface treatment methods
The surface treatment of aluminum ceilings aims to protect the surface layer of aluminum materials from oxidation and have satisfactory color effects. There are many kinds of surface treatment methods, and the three most commonly used are roll coating, spraying, and laminating. The aluminum materials processed by the three methods are called roll-coated plates, spray-coated plates, and film-coated plates.
1. Roller coated board
1. Raw materials and technology
Roller coating method: Coat the surface of the aluminum material with the paint required by the customer and form a coated aluminum coil after high-temperature baking. In order to ensure the adhesion of the coating, it is necessary to clean the aluminum before coating to make it easy to bond with the paint.
There are 4 types of paints used for roller coating boards: acrylic, polyester, fluorocarbon, and nano.
*Acrylic is a kind of resisting paint (plastic), which is hard and brittle. It is easy to dry and crack when bent. It is rarely used in high-end ceiling construction.
*Polyester is a low-density plastic, which is flexible and produces strain when bent. Polyurethane is added to polyester to make it softer.
*Fluorocarbon is a coating material produced in the United States. The combination of fluorine and carbon has excellent stability and will not change color under wind, rain and sun. This is an excellent material for outdoor projects.
*Nano is the use of physical and chemical methods to minimize the molecules of polyester and fluorocarbon, so as to achieve nanometer and form a new coating. It is characterized by brightness, strong self-cleaning, no oil and dust. Add it to the standard coating surface during construction. The coating is equipped with single coating, double coating, triple coating and other processes. Single application means that the paint is applied once. Double-coating is to coat the primer first and then the top coat. The double-coated paint is thicker and has better protection effect, so the quality of the paint is better when bending. Therefore, the double-coating process is generally used in the materials for high-end ceilings. The third coating is based on the first two layers, and then a layer of varnish is added.
2. Advantages and disadvantages of roller coated board
Advantages: The paint is fine and smooth, like "apple peel". The paint has good adhesion to the aluminium sheet and has a long service life. Paint can not replace the thickness of the aluminum plate. Because afterwards, it cannot be painted. Using paint to offset aluminum is uneconomical in terms of price.
Disadvantages: high requirements for aluminum, inferior aluminum cannot be painted. The coated aluminum of some special-shaped panels cannot be constructed. If applied, the paint surface will be damaged and cannot be repaired afterwards.
3. Inspection index of roll coated board
The excellent roller-coated board should be used in the construction of aluminum ceiling, so as to have a good ceiling effect. The acceptance of roll-coated plates generally adopts the standard numbered GB/T17748-1999 in the aluminum-plastic composite industry.
Check the grade, specification, size and flatness of the coated aluminum substrate during acceptance, and pay attention to the quality of the paint. For example, there is no paint peeling off the product after processing, and the surface is smooth, without scratches, unevenness, color difference, missing coating, spots, ribbons, etc. When the paint film thickness is 0.02mm, the T-bend should not be greater than 2T.
The surface color difference of aluminum ceiling is called color difference. If there is color difference, it will seriously affect the construction quality. In the production process, even if the same equipment and the same process are used, the colors of products produced at different time periods will have subtle differences. For example, in a project, there are tens of thousands of square meters of ceiling panels, which are supplied in batches and produced in batches. As a result, color difference will appear. Now, when using the identification instrument, the color difference is required to be △E=2, see GB/17748-1999 target.
2. Spraying board
The process of spraying plate is just the opposite of that of roller coating. It is to first shape the light aluminum plate according to the drawing, then polish it, and send it to the cleaning tank for alkaline washing and pickling. After that, send it to the spray booth for spraying and baking.
The spraying method is divided into electrostatic adsorption method and non-electrostatic method. There are also dry powder spraying and liquid spraying. Some of the paints used are suitable for indoor use, and some are suitable for outdoor, namely anti-aging materials. The spraying thickness of the surface of the aluminum plate is generally 50~100μm, which is several times thicker than the paint surface of the roller coating.
The spraying process is performed after the aluminum plate is formed. The small defects of the aluminum plate itself and the small defects newly added when the aluminium sheet is formed can be compensated by the spraying process. The spraying process has considerable flexibility.
The equipment used for spraying is mainly spray gun and baking box. The model and style of the equipment are different, and the price difference is correspondingly large.