Why Is Aluminum Processing Widely Used in Curtain Wall Systems?

1, Lightweight and High Strength: Breaking the Physical Limits of Building Height and Form
The density of aluminum is only 2.7g/cm ³, which is about one-third of that of steel, making it an ideal choice for high-rise building curtain walls. Taking the Shanghai center Building as an example, 36000 profiled aluminum plates are used on its facade, reducing the overall weight by 1200 tons and directly reducing the foundation cost by about 15%. More importantly, the strength to weight ratio of aluminum material far exceeds that of traditional materials -6061-T6 aluminum alloy has a tensile strength of over 340MPa and can withstand wind loads of level 12, while steel of the same strength weighs more than three times that of aluminum.
This lightweight and high-strength characteristic also gives curtain wall design greater freedom. The Guangzhou Grand Theatre uses 30000 pieces of hyperbolic aluminum plates and achieves a curved shape with a minimum radius of 0.5 meters through CNC machining. The splicing error is controlled within 2mm, perfectly presenting Zaha Hadid's fluid architecture concept. In contrast, stone curtain walls are difficult to achieve complex curved surfaces due to their excessive weight; Glass curtain walls are limited by the rigidity of glass and have limited space for innovative forms.
2, Weather resistant and anti-corrosion: building an all-weather protection system
The curtain wall system is exposed to the atmospheric environment for a long time and needs to resist the erosion of corrosive media such as ultraviolet rays, acid rain, and salt spray. The 10-30 micron aluminum oxide film naturally formed on the surface of aluminum can effectively block the penetration of oxygen, moisture, and most acidic gases. In extreme environments, the corrosion resistance of aluminum can be further improved through surface treatment techniques such as anodizing and fluorocarbon spraying
Anodizing treatment: An oxide film of 20-30 microns is generated through electrolytic reaction, with a porosity of less than 5%. After sealing treatment, the corrosion rate in a 5% NaCl solution is reduced by 80% compared to untreated materials.
Fluorocarbon Spray Coating (PVDF): Using trifluorochloroethylene vinyl ether copolymer, the coating contains more than 70% fluorocarbon resin and can withstand 4000 hours of salt spray testing (ASTM B117 standard). After 20 years of ultraviolet irradiation, the light retention rate is still greater than 85%. The aluminum curtain wall of the Burj Khalifa in Dubai has been tested by a temperature difference of 50 ℃ and sandstorms for 15 years without coating peeling off.
Electrophoretic coating: Deposition of 0.02-0.04mm epoxy resin coating on anodized film can fill the micropores of the oxide film and improve salt spray resistance to over 2000 hours. It is commonly used for coastal building curtain walls.
3, Precision machining: achieving digital breakthroughs in architectural aesthetics
The ductility and plasticity of aluminum make it an ideal material for the digital construction era. Through CNC machining, laser cutting, waterjet cutting and other processes, aluminum workpieces can achieve millimeter level precision control:
Manufacturing of irregular components: Shenzhen Ping An Financial Center adopts prefabricated aluminum plate modules and achieves batch production of complex geometric shapes through a five axis linkage machining center. The daily installation area reaches 300 square meters per team, which is four times faster than traditional wet operations.
Parametric design support: The curtain wall of Beijing Daxing Airport uses 85% recycled aluminum, and generates 30000 aluminum plates with different curvatures through parametric algorithms. Each plate has a unique number, achieving digital assembly construction.
Functional integration innovation: The latest nano coating technology enables the self-cleaning rate of aluminum plates to reach 90%. The photocatalytic aluminum plates used in the Beijing Winter Olympics venues have a PM2.5 degradation efficiency of 78%; The integrated photovoltaic aluminum panel (BIPV) has a conversion efficiency of 19.3%, achieving energy self-sufficiency for the curtain wall system.
4, Whole life cycle economy: comprehensive optimization from cost to value
Although the unit price of aluminum is higher than that of steel and stone, its full lifecycle cost advantage is significant:
Reduced installation costs: Aluminum has low density, and transportation and lifting costs are reduced by 40% compared to stone; The prefabricated construction mode reduces the construction period by more than 30%.
The maintenance cost has sharply decreased: the average annual maintenance cost of fluorocarbon sprayed aluminum panels is only 5 yuan/square meter, while stone curtain walls require regular cleaning and joint filling, with an average annual cost of 25 yuan/square meter. Based on a 20-year cycle, aluminum panel curtain walls can save approximately 380 yuan/square meter.
High residual value recovery rate: Aluminum materials can be 100% recycled and reused, with a recycling energy consumption of only 5% of the original aluminum. The curtain wall project of Beijing Daxing Airport reduces carbon emissions by 12000 tons through the use of recycled aluminum, achieving a win-win situation of economic and environmental benefits.