Aluminium, and more specifically aluminium alloys, is currently one of the most widely used materials in the manufacturing industry and especially in CNC machining. Low weight, very good mechanical properties, natural corrosion resistance or susceptibility to surface improvement processes make this material the material of choice for parts in many industries. In addition, the wide range of alloys (from almost pure aluminium - 1xxx series, to the highly specialised 8xxx series) allows the selection of a material with the right mechanical or cutting parameters - depending on the needs or purpose of the manufactured part.
What is aluminium machining and why is this metal alloy now so widely used in most industries - from white goods to automotive and aerospace?
What is aluminium machining and more
Aluminium machining refers to manufacturing processes focused on:
- changing the shape of a block of raw aluminium alloy by machining - e.g. turning, cutting, grinding, traditional and numerically controlled - which can be collectively referred to as aluminium machining,
- changing the shape of aluminium alloy blocks by rolling or bending them to the extent of their elasticity (natural cold, extended hot), referred to as plastic working of aluminium, e.g. on CNC press brakes,
- additional surface treatments to improve the mechanical properties or increase the natural corrosion resistance of aluminium alloys (electroplating of aluminium), e.g. anodising.
Another important machining process is the casting of aluminium, which, due to the high melting point of this metal (for pure aluminium - 660 degrees Celsius), is a large-scale process carried out in specialised smelters and foundries. In addition, the material itself may undergo other processes to improve its mechanical performance - either before (e.g. forging) or after (e.g. aluminium hardening) machining.
The colloquially accepted term 'aluminium processing' refers to the processing of aluminium alloys, usually with the addition of other elements such as:
- magnesium (Mg),
- copper (Cu),
- manganese (Mn),
- zinc (Zn),
- silicon (Si).
These alloying additives change the mechanical parameters of the metal, increasing its strength or reducing its susceptibility to corrosion. Different types of aluminium are also characterised by a different susceptibility to machining - a commonly used process for machining aluminium. One common division of aluminium alloys is based on EN 573-3:2019-12, which defines the following aluminium series:
- 1xxx series - in practice, pure aluminium, without alloying additives (aluminium of near or technical purity, more than 99%). It is characterised by good thermal and electrical conductivity, and the metal itself is soft and extensible. Rarely machined, it is often used in heat dissipation systems (e.g. heat sinks) or older electrical installations,
- 2xxx series - aluminium alloy with added copper. More susceptible to corrosion, often used for aerospace parts,
- 3xxx series - aluminium alloy with added manganese. Relatively soft, also retains good mechanical properties at higher temperatures. Most often formed by plastic working,
- 4xxx series - an aluminium-silicon alloy. Characterised by good mechanical and strength properties and increased corrosion resistance,
- 5xxx series - aluminium-magnesium alloy. Aluminium components made of this alloy are characterised by very high resistance to corrosion caused by saltwater and it is also very susceptible to machining,
- 6xxx series - aluminium-magnesium-silicon alloy. In addition to high mechanical strength, this alloy series is characterised by good thermal conductivity. Often used for the production of bicycle parts,
- 7xxx series - aluminium alloy with the addition of zinc and magnesium. Sometimes referred to as "aircraft aluminium", it is characterised by very high mechanical strength and at the same time good machinability. Used to produce high-quality parts for many industries - including automotive, aerospace and military,
- 8xxx series - these are highly specialised alloys that do not qualify for any of the above series.
Such a wide range of aluminium series makes finding the right alloy for the production of components relatively easy, especially with the help of experienced specialists with extensive knowledge of materials science - such as those working at RADMOT.
Types of aluminium processing
It is worth extending the aforementioned division into machining, forming, chemical and casting of aluminium alloys. Today, many industries require specialised parts made from a wide range of aluminium alloys. The most common is aluminium machining, which can be divided into:
- aluminium milling - based on the removal of excess material from an aluminium block using milling cutters and specialised cutting equipment (milling machines - automatic and numerically controlled: CNC). In this process, it is possible to obtain parts with very complex external and internal structures (e.g. using 5-axis CNC milling machines),
- aluminium turning - focused on the removal of excess material from a block rotating on a turning head using special blades or drills. This process is used in the manufacture of objects with one of the axes following a circular shape,
- aluminium grinding - used to finish the surface of aluminium.
Each of these processes can be carried out using traditional cutting machines as well as numerically controlled equivalents. In addition, the machinery park CNC of companies specialising in the manufacture of metal or plastic parts - such as RADMOT - also includes equipment for electroplating aluminium parts (e.g. anodising).
Is aluminium machining a novelty?
Although aluminium is the third most common element in the earth's crust, its use on an industrial scale dates only to the late 19th century. Aluminium itself was already known earlier - it appears, among other things, in the accounts of the ancient Romans. According to legend, a goldsmith showed the Emperor Tiberius the so-called 'silver metal of aluminium'. Also Napoleon III Bonaparte, at his most solemn banquets, recommended serving food on aluminium crockery, then considered exclusive. Today, aluminium seems to have become commonplace. This is mainly due to the availability of efficient processes for extracting and processing aluminium ore, which, however, require a great deal of energy.
Aluminium itself is obtained by reduction of impurities from bauxite ores (consisting mainly of aluminium hydroxide) and deoxidation (e.g. by aluminium hydrolysis or Hall-Heroult electrolysis). For industrial purposes and further processing, the metal is combined with the elements mentioned, such as copper, manganese, silicon, magnesium and zinc. This produces the right material properties for industrial use of aluminium alloys.
Key benefits of aluminium alloys
Among the many characteristics of aluminium alloys, there are several that are particularly important from the perspective of the quality of parts made from this metal:
- despite being lightweight, they do not lose their durability - the tensile strength of aluminium alloys (depending on the alloy used) starts at 70MPa and goes up to 700 MPa. Their strength increases at low temperatures, which significantly distinguishes them from most steels. Research by Professor Michael Stacey indicates that the service life of aluminium can be as long as 80 years - no other material offers such a life (research was conducted on aluminium window frames),
- are corrosion-resistant - a layer of aluminium oxide is formed on the surface of aluminium parts, in contact with atmospheric air, which protects against corrosion under conditions of moderate sulphation. The appearance of pitting corrosion does not affect durability, but it does affect aesthetics - it manifests itself as a characteristic white film on the surface. This can be prevented by anodising the aluminium or by powder coating the parts,
- most aluminium alloys are easy to machine - both by cutting and by forming (depending on the alloy chosen),
- aluminium alloys have good conductive properties - hence they are a valued material in electrical engineering due to their ability to conduct heat (e.g. in heat-dissipating parts such as radiators or heat sinks) as well as electricity (aluminium conductors were used in older electrical installations; it is worth mentioning that anodising reduces electrical conductivity to practically zero, which is why it is such an important process in the production of parts for power installations),
- they are environmentally friendly - many aluminium alloys can be re-melted, in practice without any loss of properties (recycling aluminium uses about 5% of the energy required to obtain a similar amount of metal from the ore).
Applications of aluminium processing in various industries
Nowadays, aluminium alloys are widely used in almost every industry. Due to their low weight and good mechanical parameters and corrosion resistance, aluminium parts are used by:
- the aviation industry - which was the first to seek CNC milling services for aluminium and other metals in the 1950s. Currently, aluminium is the basic metal used to produce a wide range of parts for civil and military aviation,
- automotive industry - low weight and high corrosion resistance make aluminium parts widely used by car and car parts manufacturers - from engine blocks (aluminium has largely replaced cast iron), through entire vehicle frames, to small decorative elements or rims,
- energy industry, in particular renewable energy - light frames of photovoltaic panels are resistant to weather conditions, which reduces the need for maintenance and at the same time ensures high technical parameters for years,
- military industry - aluminium is the basic material for the production of modern weapons (e.g. MSBS Grot carbines),
- electronics industry - due to their low weight and machinability, most household appliances and electronics (from phones, frames to tablets, to refrigerators and washing machines) have larger and smaller components made of aluminium alloys, most often cut,
- and many others.
Precise aluminium machining and unique design
Aluminium is also used due to its aesthetic values. The white-silver color, the possibility of additional surface treatment (e.g. anodizing of aluminium using SALANDOR organic dyes) and the ease of processing make aluminium alloys widely used in the production of high-quality products that combine good design with durability.
The possibilities offered by CNC machining of aluminium inspire many designers and engineers to use structural purposes to provide products with a unique appearance. An example would be Displine tablet frames, which combine functional and aesthetic features.
How do aluminium alloys fit into ecology?
Due to growing needs and developing living standards, care for the environment is also required. The use of aluminium alloys supports the development of innovative and ecological solutions. For example, recycling aluminium requires only about 5% of the energy required to produce it from scratch from ore.
How do we handle aluminium at RADMOT?
The key in our company is the appropriate selection of material suppliers - also for CNC aluminium machining. Classification and periodic assessment of the quality of aluminium blocks used for processing is extremely important to maintain the highest possible quality of production. Precise aluminium machining requires the work of experienced technologists as well as the use of the highest quality material.
One order, many benefits - this is how you work with RADMOT
At RADMOT, we offer CNC milling services, CNC turning services, as well as many additional services, including washing, aluminum anodizing, laser marking and assembly. We have at your disposal over 80 modern machines in our machine park, all from renowned manufacturers. Download the presentation and check on which machine tools we produce CNC turned parts and CNC milled parts.
Contact us and tell us what you need. We have been providing CNC services for almost 40 years. Our valuation is completely free. And if you're in doubt about which technology will work best for you, our expertise is at your service.
