Aluminum Composite Panels, which are also called ACP materials, are popular construction products that are widely used in modern building architecture. These panels are not just a reverberation for interior or exterior designers and architects but also are beneficial for the environment. They are considered new sustainable materials known as sandwich sheets and brought new fields to the architecture. This means the composite panels do not just increase the durability of modern buildings but also contribute making the whole world sustainable and cleaner. Thus, using them has been expanded in the last few years to cover up energy efficiency and low price possibilities. Additionally, they are specially created for the ventilated facades rehabilitation and renovation.
Obtaining Aluminum from Nature
Aluminum is one of the most common elements found in the mother earth’s crust. However, the pure material that is used for developing different industrial products such as ACP does not occur naturally. Thus, there is a standard process defined for obtaining the usable material. This process is broken down into three main stages, which are extracting bauxite, turning them into alumina, and then producing pure material using electrolytic reduction. Bauxite, which is found naturally on the surface of the ground, contain aluminum in their structure and is made up of aluminum oxide mixed with other elements and minerals. Experts extract this material by using open-pit mines. For turning the material into alumina, a common process, which is called Bayer, is utilized. The produced alumina has an unlimited shelf life.
However, it should be stored under precise conditions due to its property of absorbing moisture. After this process, for creating the pure material, another component is required for creating the best environment for electrolysis, which is called Cryolite. In modern manufacturing systems, it is made by mixing up aluminum hydroxide, soda, and hydrofluoric acid. The last stage of producing pure aluminum is the electrolytic reduction, which requires an area for smelting the material. This area consists of many large rectangular constructions, which have a length that exceeds one kilometer. Inside these buildings, there are hundreds of pots or cells arranged in rows, which are connected to power sources through massive cables. In each of these cells, pure aluminum is being developed from alumina. The material is extracted from the cell by using a special vacuuming bucket for two to four times per day. A hole needs to be created in the cryolite and then the liquid aluminum is sucked into the bucket through a pipe connection.
Production of Aluminum Composite Panels
Aluminum composite panels can be produced in different methods and ways. The production procedure can be divided into two methods of cold composite and thermal composite. These two can additionally be classified with continuous and intermittent methods. ACM is generally manufactured by joining thin aluminum skins to both sides of a lightweight core, which is typically thermoplastic.
The production process of aluminum composite panels starts with cleaning the coil material. This material, during its creation, due to the needs of the process, is coated with anti-oxides and lubricants, thus a speck of considerable dirt and dust will be attached to the material during transportation. This can affect its adhesion thus precise cleaning is required. After coil cleaning and chemical treatments, a dense protective film starts to form on the surface of the material. This coat can improve the oxidation resistance of the panels and will increase the lifetime of the paint finish.
The produced panels of exterior composite sheets are coated with two layers of primer and paint. The top layer of the cladding materials is an extreme weather-resistant fluorocarbon, which has, resin substance and called polyvinylidene fluoride. This coat keeps the surface of the product protected due to its ideal UV resistance and environmental pollution characteristics. In addition, the surface can have beautiful marble color and pattern, which makes it perfect for creating modern architectural designs. The fluorocarbon substances are usually applied to the coils by roll process and then baked at lofty temperatures for drying. The last layer of coating is a varnish surface and this creates a total thickness of 30 micrometers. Each of these layers must be baked and dried at 200 degrees of Celsius for almost 60 seconds. After the drying process, the heating oven must be cooled by an air cooler. The interior wall paint is generally made of polyester, epoxy resin, or acrylic. It is important to have precision during installation and transportation for preventing any further damages on the product such as surface scratches.
The protective film, which is a self-adhesive material, needs to be removed after the installation procedure. Then, the aluminum coil, which is coated with fluorocarbon resin, can be compounded with the core material. This material is also a three-layered substance that contains adhesive on both sides and PE plastic in the middle section. In the case of Alpolic materials, the core portion can be either a proprietary mineral-filled, fire-resistant, or polyethylene material. In both cases, the standard layers will be produced in 0.5mm thickness. Some Heavy-duty skins that have 0.8 thicknesses are also available on the market. The completed ACP material is available in 3mm, 4mm, and 6mm thickness that the last one is the most used thickness for the building industry. However, there are some custom sizes available for special demands.