Aluminum

This is the youngest metal in our collection. It's hard to imagine, but just 200 years ago, people had no concept of this divine gift and knew nothing about it. However, the scientific world of that time sensed the imminent emergence of a new wonder of nature, and dozens of chemists sought access to it. It is the most abundant metal in the Earth's crust, occurring naturally in solid compounds with oxygen, and its extraction in metallic form proved extremely difficult and was inaccessible to the best minds of chemical science for a long time.

The birth took place in the year 1825. In those years, humanity stood on the threshold of a scientific and technological revolution, an enormous potential of knowledge had been accumulated, and the most astonishing discoveries awaited us. This eagerly awaited child of science was born in the laboratory of the brilliant Hans Christian Oersted, and some parts of a gram of metallic aluminum first appeared before the eyes of people.

The subsequent events were linked to the search for industrial technologies for the production of aluminum. Thanks to the immense efforts of industrialists, politicians, scientists, metallurgists, and the power of scientific and technological progress, humanity gained the aluminum industry, which forever changed the face of our civilization - aluminum gave us wings, it allowed us to fly! Modern aircraft are made up of 80% of this heavenly metal. It loves speed - thanks to the lightweight and sturdy construction of powerful aluminum engines and car bodies, we have learned to drive fast. The industry needs it for a variety of purposes, from electricity and medicine to construction and food technology. Yes, this is an interesting history, but what does it have to do with art? Well, everything we've written so far came later. In the beginning, it was the most valuable, stylish, and precious metal on Earth! At receptions of Napoleon III, the most expensive guests sitting near the emperor were served with aluminum tableware, while the rest of the nobility had to make do with simple gold spoons and forks. Using aluminum for minting coins was out of the question. For commemorative medals and high honors, relatively inexpensive materials like gold, silver, and platinum were much better suited. Jewelry in the form of aluminum buttons could only be worn by royal personalities, while small aluminum rings or bracelets adorned the hands of noble individuals in Europe, Japan, and Asia. Jewelers, sculptors, artists, designers, and architects appreciated the beauty and utility of this metal, and to this day, there are and always will be individual areas of these arts that use aluminum.

Its natural beauty, lightness, good workability and excellent casting properties enable us to create unique masterpieces of sculpture, building components and façade compositions from this marvellous gift of nature.

It's amazing how art and design are influenced by the availability and use of different materials.

Façade with cast aluminium façade elements
Aluminium casting sculpture Arcimbolda by Jana Mertens

Cast aluminum

Aluminium casting refers to the process of casting aluminium into a mould to obtain a desired shape or structure. This process is widely used in metalworking and manufacturing to produce various products, from small household items, façade elements, aluminum sculptures, design objects to large industrial components.

The aluminium casting process takes place in several steps:

  1. Mould preparation: First, a mould is created that represents the desired shape of the end product. This mould can be made of metal, sand, ceramic or other materials.

  2. Melting the aluminium: The aluminium is heated to high temperatures in a melting oven until it melts and becomes liquid. The melting point of aluminium is around 660 degrees celsius.

  3. Casting: The liquid aluminium is then poured into the prepared mould. It fills the mould and takes on its contours.

  4. Solidification and cooling: After casting, the liquid aluminium is left to solidify in the mould and cool until it solidifies and retains the desired shape.

  5. Demoulding: Once the aluminium has cooled completely, the mould is opened and the finished aluminium casting is removed.

Model making with CNC milling machine for aluminium casting

The aluminium casting process

How are aluminium sculptures, façade elements and components made?
For an aluminium foundry, there are several casting processes that are suitable for processing aluminium. The choice depends on various factors such as the desired end product, the geometric requirements, the quantity and economic considerations. Here are some of the most common casting processes for aluminium:

  1. Sand casting: This is one of the oldest casting techniques and is used for simple to complex moulds. Sand casting is cost-effective and is well suited for prototypes and small series.

  2. The lost wax process, also known as investment casting or precision casting, can also be used for aluminium. This process enables the production of high-precision and detailed aluminium parts.

  3. Mould casting (die casting): This process is used for the mass production of aluminium parts with high precision. Aluminium is poured into a permanent mould (die), which is closed under pressure. The cooling time is short, resulting in fast production cycles.

  4. Pressure die casting: Similar to permanent mould casting, but the molten material is injected into the mould under pressure. This enables the production of parts with thin walls, tight tolerances and high surface quality.

  5. Investment casting: This precision casting process is suitable for complex parts with fine details. It uses lost wax moulds to produce highly detailed aluminium parts.

  6. Low-Pressure Die Casting: Here, aluminium is poured into a mould that is subjected to low pressure. This process is well suited for large and complex parts.

  7. Gravity die casting: In this process, molten aluminium is poured into a mould that is filled by gravity alone. It is suitable for larger parts with less complex geometries compared to other die casting processes.

  8. Vacuum casting: The vacuum casting process, also known as vacuum die casting or vacuum pressure die casting, is a form of die casting in which the casting process is carried out under a vacuum.

Advantages of choosing aluminium in castings

What are the special features of aluminium?
Compared to other metals, aluminium offers outstanding advantages for post-processing. Its lightness, good machinability and excellent casting properties enable engineers, artists, designers and architects to create a wide range of artworks and components.

  1. Lightweight: Aluminium is a light metal, which makes it easier to handle and transport. This is particularly important for large parts or assemblies.

  2. Good machinability: Aluminium alloys are easy to machine, which means that they can be processed, cut, milled and drilled relatively easily. This facilitates post-processing and enables precise shaping.

  3. Corrosion resistance: Aluminium forms a thin oxide layer on the surface, which protects it from corrosion. As a result, the material remains resistant to environmental influences even after processing.

  4. Good thermal conductivity: The high thermal conductivity of aluminium enables efficient cooling during the machining process, which increases the service life of the tools.

  5. Recyclability: Aluminium is 100% recyclable without any loss of quality. This promotes sustainable production and reduces the need for primary aluminium.

  6. High strength-to-weight ratio: Aluminium alloys offer good strength at a relatively low weight. This is particularly beneficial in applications where weight plays a role, such as in the aerospace industry.

  7. Formability: Aluminium alloys are easy to shape and can be formed into different shapes using various processes such as pressing, rolling or forging. This facilitates the production of complex parts.

  8. Aesthetic appearance: Aluminium has a natural, attractive surface and can be easily anodised or coated to achieve different visual effects. This is particularly important in industries such as consumer product design.

However, it is important to note that the selection of the best material for finishing also depends on the specific requirements of the application, including mechanical properties, environmental influences and cost. Aluminium casting is used in various industries, including automotive, electronics, construction, aerospace, art & design and many others.

Sustainability and health

Aluminium is not only versatile, but also sustainable. The recyclability of the material helps to protect the environment. In addition, aluminium is harmless to health and is valued in various industries, from food technology to medicine.

Aluminium casting Casting process
Cast aluminium model

Typical problems of aluminium casting

An aluminium foundry must adhere to precise processes in order to achieve optimum results. Experience and expertise play a decisive role here. Various typical problems can occur in aluminium casting that can affect the quality of the cast parts:

  1. Porosity: Porosity occurs when gas bubbles are trapped in the aluminium alloy during the casting process. This can affect the mechanical properties of the cast part.

  2. Oxidation: Aluminium reacts easily with oxygen, which can lead to oxidation. Oxide layers on the surface of the molten metal can be incorporated into the cast part and impair the mechanical properties.

  3. Inclusions: Foreign materials, such as slag or other impurities, can get into the mould and lead to inclusions in the cast part. This can impair the strength of the part.

  4. Shrinkage: Shrinkage can occur when the molten aluminium cools, which can lead to dimensional deviations in the end product.

  5. Work hardening: This occurs when the cast aluminium is cooled too quickly, which can lead to increased hardness and brittle behaviour.

  6. Casting artefacts: Unevenness, scratches or other irregularities on the surface of the cast part can be caused by moulding problems or poor casting practices.

  7. Insufficient filling of the mould: If the mould is not completely filled, voids or incomplete parts may result.

  8. Heat affected zones: Insufficient cooling can lead to heat-affected zones, which can affect the microstructure and therefore the strength of the material.

Although aluminium casting offers many advantages, there are certain challenges to overcome. These include controlling the casting temperature, avoiding air inclusions and selecting the right alloy. As an aluminium foundry, we continuously use innovative technologies to minimise these problems and to precisely control the casting process parameters, ensure the purity of the melt, use suitable casting moulds and carry out careful post-processing and inspection.

Benefit from our generations of experience in the manufacturing of excellent sculptures, components and products made of aluminium.

All castings
Request now