As a kind of aluminum curtain wall product, aluminum-plastic panel curtain wall products have the advantages of easy processing, economical and practical, and high quality compared with single-layer aluminum curtain wall and honeycomb aluminum curtain wall. It is the most widely used aluminum panel curtain wall product. The biggest variety. This series of advantages of aluminum-plastic panel curtain wall has promoted the tremendous development of aluminum-plastic panel curtain wall in China in just ten years. Figure 3 shows the aluminum-plastic panel curtain wall project designed, processed and installed by China. However, the current status of the aluminum-plastic panel curtain wall in China and a series of problems revealed by it are also caused by the abuse of these advantages.
Turn easy processing into shoddy
The easy-to-processability of the aluminum-plastic panel curtain wall is well known. It can be processed either in the workshop or on the spot. The processing equipment can be finished with a regular cutting planer or a simple hand tool. Because of this characteristic, there are very irregular behaviors in China's current aluminum-plastic panel curtain wall products. Some cracks appear on the edge of the curtain wall panel, and some panels are uneven, and some aluminum panels appear on the edge of the panel. Plastic core splitting and so on. The main causes of these phenomena are the following.
The slotting of the folded edge of the aluminum-plastic panel is an important processing site for ensuring sufficient strength of the aluminum-plastic panel. It is strictly forbidden to damage the back of the aluminum panel during the grooving process, and at the same time, a plastic part of not less than 0.3 mm thick must be left. However, in the current processing process, due to the inaccuracy of operation and equipment, the phenomenon of cracking of the folded portion of the aluminum-plastic plate component is often caused by cutting the aluminum plate, which greatly reduces the strength of the aluminum composite panel.
The reinforcement of the ribbed ribs and stiffeners of the aluminium composite panel assembly is the key to ensuring the strength and flatness of the aluminum torsion panel assembly. However, there are many problems in the process of assembly and assembly. If the design of the reinforced ribs and stiffeners does not meet the requirements of the specification, the strength of the ribs is insufficient and the number of stiffeners is insufficient. There are also many defects in the connection of the reinforcing ribs and stiffeners to the aluminum-plastic panel, and in particular, the connection of the stiffeners to the back of the aluminum-plastic panel has more problems. Since the aluminum composite panel cannot be connected to the stiffener by means of an electric welding screw, structural bonding can only be achieved by using a structural double-sided adhesive strip or structural adhesive. Both of these bonding methods require operation in strict operating specifications, otherwise the necessary bonding strength benefits will not be achieved. At present, many aluminum-plastic composite panels are not operated according to the specifications, resulting in the aluminum-plastic composite panel assembly being installed before, or after a period of installation, the bonding of the stiffeners to the panel has failed and separated, so that the aluminum-plastic composite panel is under the action of wind load. The convexity and convexity are uneven, and the strength is lowered, which seriously affects the use function of the aluminum composite panel.
Because the aluminum-plastic composite board is made of two-layer aluminum plate with LDPE board inside and outside, it is strictly prohibited to cut the edge or the processing hole of the aluminum-plastic board without being decorated and sealed directly in the process of use. Otherwise, the aluminum sheet and the aluminum sheet will be Splitting of the composite layer. There are some construction units. In order to save materials, the aluminum-plastic panel is often used directly without trimming, which causes unfortunate serious consequences.
Turn economics into a low-cost product.
The reason why the aluminum-plastic panel curtain wall is economical and practical is mainly from the price and easy processing performance of the aluminum-plastic panel product itself. In terms of the price of the sheet metal itself, the price of the aluminum composite panel product itself is generally more than twice the price of the aluminum composite panel compared to the price of the aluminum honeycomb panel. Compared with the aluminum plate assembly after the completion of the production, the cost per square meter of the aluminum composite panel assembly is lower than about 30% of the single-layer aluminum plate assembly. However, in order to cope with the requirements of market competition and blind price reduction, many aluminum-plastic panel manufacturers and curtain wall manufacturers have serious problems of cutting corners in the selection of materials. The specification clearly stipulates that aluminum-plastic panel curtain wall panels must use two layers of 0.5 mm thick. Made of aluminum alloy plate, the outer aluminum plate surface must be treated with fluorocarbon coating. The reality is that the composition of the aluminum alloy panels of many aluminum curtain wall panels does not meet the requirements, the thickness of the outer aluminum panels is less than 0.4mm, and the thickness of the inner panels is reduced to 0.3mm, and some even have 3mm thick interior walls. The board is used directly for the siding. Even the cold pressed plate that has been eliminated is used as the outer wall board, and the result is that the panel and the composite plastic are separated due to insufficient bonding strength.
Think of high-tech products as low-end products
Due to the existence and influence of the above problems, aluminum-plastic composite panels, which should be high-tech products, and aluminum-plastic composite panels, which use aluminum-plastic composite panels as panel materials, have been regarded as unreliable or low-grade in people's minds. product. In the selection of curtain wall products, there are often many concerns. Most of the important or high-rise buildings generally no longer use aluminum-plastic panel curtain walls.