From ingot to icon

In the world of modern architecture, innovative material technologies, avant-garde design and sustainable strategies come together to create a fascinating symbiosis that constantly redefines the limits of what is possible. Of all the materials available to architects for this task, anodized aluminium has the edge in terms of versatility and aesthetics. From exterior façades and interior wall and ceiling designs to door panels and decorative elements for other applications - anodized aluminium offers virtually unlimited possibilities as an architectural material.Aluminium as a material has very good formability, allowing architects to experiment with unusual designs, geometries, and intricate details. The production of anodized aluminium coils, plates and sheets, such as those in the AMAG architectural portfolio, also opens up a wide range of color, surface, and texture options. However, the journey from raw aluminium to the finished façade panel is long and requires a series of carefully coordinated production steps as well as seamless cooperation between the various actors in the architectural supply chain.

The journey begins in the foundry

The “quality in, quality out” principle is particularly relevant to the production of aluminium façade products. To ensure that only the highest quality products are created from the start of the production process, AMAG manufactures the rolling slabs for its architectural products in its own foundry while maintaining precise process monitoring, because the different aluminium alloys react differently to anodizing and vary in color depending on their composition. The solidification conditions and different filter techniques during the casting process are the basis of a homogeneous microstructure, and ultimately for the uniform appearance of the anodized façade later on.

All quality control parameters firmly in hand

The rolling slabs produced in this way are rolled in the AMAG rolling mill to the dimensions and surface finishes specified by the customer. Precision and expertise are essential here, too, as any irregularities on the coil surface can be exacerbated during anodizing: microstructural properties of the material can influence the visual properties of the anodized surface (gloss and color properties). For example, etching behavior and etching depth are affected by grain orientation and may lead to increased surface roughness after etching if the grain orientation is unfavorable. Higher surface roughness in turn leads to changes in reflective properties and results in lower gloss after anodizing. If the grain distribution within a single aluminium sheet or between two sheets is uneven, this can result in an irregular outward appearance.This is why AMAG leaves nothing to chance in these process steps. A specific hot rolling regime and targeted heat treatment processes, specially developed for surface-sensitive products, are needed to ensure the required element distribution and fine grain structure during downstream processing after casting. The rollers used for this are specially prepared in AMAG’s own roller grinding shop. The world’s widest bright rolling mill, which can be used to produce surface-sensitive products in widths of up to 1,500 mm and thicknesses of up to 3 mm, is available for roller burnishing. AMAG’s investment in a new surface treatment line for etching and surface treatment of the façade material also reflects the company’s commitment to meeting the highest customer expectations for anodizing and visual quality.When it comes to quality assurance, AMAG also relies on its extensive expertise in-house - or, to be precise, in its own anodizing technical center, which is in the Center for Material Innovation, AMAG’s materials research and testing center. Before the sheets and coils are delivered to AMAG customers for anodizing, anodizing tests are carried out there for each batch produced and the gloss and, if necessary, the color properties are checked - because only flawless products meet AMAG’s premium standards.

AMAG’s unique positioning as an integrated facility with foundries and rolling mills at the same site means that all of the above parameters can be coordinated quickly, flexibly and seamlessly. This forms the foundation for an ideal, reproducible etching and anodizing result.

The alchemy of anodizing

Anodizing is an electrochemical process that improves the corrosion resistance, durability and appearance of aluminium. It involves creating a controlled oxide layer on the surface of the metal by immersing it in an electrolyte bath and passing an electric current through it. The combination of a high-quality base product and the expert knowledge of our customers who specialize in anodizing aluminium not only ensures uniform growth of the oxide layer, but also makes it possible to regulate its thickness, which affects the hardness and durability of the aluminium surface and makes it more resistant to scratches and wear. The thickness of the oxide layer generally ranges from less than 1 micrometer for technical applications to 25 micrometers for exterior façades. The anodizing process also allows for a variety of color options and offers architects and designers the flexibility to achieve specific aesthetic goals. Unlike painted surfaces, anodized surfaces are firmly bonded to the aluminium, making them less susceptible to fading, chipping or flaking. The color stability ensures that the façade retains its original appearance over long periods of time.

Two primary techniques are commonly used for anodizing aluminium: batch anodizing and coil anodizing. While batch anodizing allows for forming flexibility and customization, coil anodizing delivers speed and cost efficiency for large-scale, standardized production and offers excellent color consistency over large quantities. Thanks to the flexible anodized film developed in the continuous coil anodizing process, the surface is ideally prepared for further processing steps such as cutting to length, roll profiling or bending. The anodizing layer is not affected by these processes following the continuous coil anodizing. The advantages of a uniform surface and surface protection are retained. This is particularly important for projects that call for a uniform appearance. The high precision workmanship behind AMAG’s architectural products means that anodizers are able to work with a starting product that is optimally designed for the anodizing process, regardless of which technology they use.The anodized architectural products can then be used for different types of façade panels, depending on the specific project requirements. In this context, the AP series is particularly suitable for façade sheets that are bonded to aluminium honeycomb structures, and for stud welding.The AMAG H14 materials are optimized for grooving, folding and bending. All products in the AMAG-AP series can be perforated. Manufacturing aluminium façade panels, from casting, rolling and anodizing to producing the panels themselves, is a complex and complicated process that calls for precision, creativity, and technical expertise. The resulting façades are enduring symbols of what can be achieved when we work together in close coordination throughout the entire process chain towards a common goal in order to provide architects, planners, designers and clients with the best possible support in making their ideas a reality.