How to achieve perfect aluminum machining: Aluminum machining live in the workshop!

Aluminum is omnipresent. We encounter it in vehicle bodies, aircraft structures, machine components, packaging and in many industrial applications. The reasons for this are obvious: the material is light, malleable, corrosion-resistant and impresses with its excellent conductivity. However, it is precisely this diversity that poses particular challenges for manufacturers. This is because aluminum machining is anything but a matter of course.

Depending on the alloy, strength and structure, it reacts very differently to machining processes. Chip sticking, built-up edge formation and abrupt tool wear are just some of the typical side effects. The challenges often lie in the details and the path to a stable, efficient process is rarely straightforward. What makes the decisive difference only becomes apparent when you delve deeper.

From lightweight to high-performance: What makes aluminum so attractive for machining

As a material, aluminum has an exceptional combination of technical properties that make it particularly attractive for machining. Aluminum naturally forms an oxide layer that protects it from corrosion, and anodizing can further enhance this protection — a clear benefit in harsh environments or for demanding surface requirements. At the same time, aluminum conducts heat and electricity very efficiently: with around 60 percent of the thermal conductivity of copper and an electrical conductivity of around 62 percent at only a third of the weight, it is ideal for lightweight, high-performance components.

The material also offers advantages both visually and functionally. It reflects up to 90 percent of thermal radiation and 80 percent of light, making it predestined for use against light and thermal radiation in applications such as roofing and heat shields for motor vehicles. In terms of sustainability, it scores highly with its excellent recyclability. Recycling uses only a fraction of the energy while maintaining full quality and strength. Furthermore, it generally does not require any additional protective coating, as simple processes such as brushing or shot blasting are usually sufficient. However, if increased protection is required, additional surface treatments such as paints or electrochemical treatments (e.g. anodizing) can be applied.

Light, strong, versatile – ideal conditions for machining

A decisive factor for aluminum machining is the excellent ratio of weight to strength. This makes the material ideal for lightweight, robust constructions, such as in vehicles or aircraft. It also impresses with its uncomplicated processing: it can be produced in almost any desired thickness. Its easy machinability – for example through turning, milling, or grinding – and the high processing speed also make production more economical. Furthermore, it is highly formable and can be processed into fine threads or complex shapes without breakage. Despite its lower ductility compared to copper, its low density and low melting point enable the flexible production of a wide range of products such as sheets, tubes or rods..

Aluminum also shows its strengths at low temperatures: it does not become brittle, but stronger, and remains corrosion-resistant. It is also non-magnetic, which makes it ideal for shielding antennas and computer panels. Anyone who wants to machine aluminum is working with a material that is not only light and conductive, but also robust, sustainable and extremely versatile. Provided you know its characteristics and use the right precision tools, such as those developed by HAM.

Not all aluminum is the same, and that makes all the difference

Aluminum is a real lightweight with amazing strength. Compared to other materials, aluminum is in the middle range in terms of strength. However, when its density is taken into account, it clearly stands out and even surpasses steel. It is precisely this ratio that makes it so attractive for lightweight construction. Aluminum has played a key role in automotive engineering, aviation, and mechanical engineering for many years.

But as versatile as the material is, it also behaves differently when it comes to machining. Because not all aluminum is the same. In addition to pure aluminum, there are a variety of aluminum alloys with their very own properties. While pure aluminum is very soft and only has low strength, alloys usually have significantly better prerequisites for aluminum machining. A distinction is made between wrought alloys and cast alloys. Both types are basically machinable but require a differentiated approach.

In practice, aluminum alloys are divided into three classes. Class one comprises very soft materials with low strength. These often produce greasy chips during machining, which stick to the tool and lead to the formation of built-up edges. Class two describes materials with increased strength in the range of around 300 to 600 Newtons per square millimeter. These alloys are significantly more stable and lead to fewer built-up edges. Class three stands for free-cutting materials and wrought materials with chip-breaking additives such as lead. These additives ensure clean chip formation and significantly reduce the tendency for built-up edge.

The biggest challenges in machining aluminum

At first glance, aluminum seems like a dream partner for machining. Light, easy to shape and clean to process. But when you stand at the machine, you quickly realize that this material also has its peculiarities. In particular, the sticking of chips and the stubborn built-up edge make even experienced machining professionals break out in a sweat. Especially when milling aluminum, these effects can have a negative impact on dimensional accuracy, tool life and surface quality.

One key to successful aluminum machining lies in high-speed machining. Combined with a carefully selected cooling lubricant strategy, many problems can be avoided from the outset. Aluminum generates significantly lower cutting forces than steel during milling, often only about a third. This property allows high cutting speeds, but at the same time requires consistent control of the chip flow.

To ensure process stability, it’s crucial to remove chips from the cutting zone quickly and efficiently. This requires special tools for aluminum with smooth, slippery surfaces that prevent sticking and actively remove the chips. Milling cutters with a lower number of teeth than tools for steel are also characteristic. This design significantly improves the chip flow. Coordinated coating solutions, when integrated into the process, reliably control even sticky aluminum chips.

These are the factors that really matter when machining aluminum

If you want to machine aluminum reliably and precisely, you have to master the interaction of many components. It starts with the machine itself. It should not only work stably, but above all be prepared for the use of modern cooling lubricant solutions. Systems like the AerosolMaster 4000 ATS from Blum-Novotest enable highly efficient minimum quantity lubrication by precisely dosing a fine film of lubricant. At the same time, the machine must support internal and external cooling options and allow clean adaptation to dry machining, emulsion or MQL.

Another cornerstone of aluminum machining is the clamping. The tool holder and workpiece holder must grip precisely to avoid vibrations and ensure clean chip formation. In MQL machining, the cooling channel must be optimally positioned to ensure effective performance. This is the only way to ensure reliable chip removal without leaving any residue in the machining zone. When drilling, for example, a special clamping structure with a central lubricant supply via the holder can be crucial.

And let’s not forget the digital side of the process. CAM programming has a massive impact on efficiency and tool life. Those who rely on well thought-out strategies and smart adjustments to the cutting values not only save time but also ensure uniform surfaces. Those who rely on well-thought-out strategies and smart adjustments to cutting parameters not only save time but also ensure consistent surfaces. Technology such as SolidCAM‘s iMachining, in combination with optimized cutting data, enables a constant load and reduces thermal peaks at the same time.

However, the optimum machine, perfect clamping and intelligent programming only unfold their full potential in combination with the right tool. This is because the cutting material, cutting values, tool geometry and surface technology determine the cutting quality and process stability, especially with aluminum. Therefore, it’s worth taking a closer look at the specific requirements of tools for aluminum machining.

What makes our tools so special when machining aluminum

What truly makes a tool for aluminum machining outstanding isn’t just the cutting material used or a single design feature. It’s the interplay of sophisticated materials, sophisticated geometry, and state-of-the-art surface technology that makes the decisive difference.

When it comes to cutting materials, we specifically focus on two proven materials: polycrystalline diamond (PCD) and solid carbide. PCD tools are the first choice for machining abrasive aluminum alloys with a high silicon content or for very high-volume production combined with long tool life. They are characterized by exceptional wear resistance and deliver consistently high surface qualities – an advantage that is particularly in demand in sensitive sectors such as aviation or automotive engineering.

Solid carbide tools, on the other hand, score points for their versatility. They are ideal for smaller series or for processes that require a high degree of flexibility. Their advantage lies not only in their good cutting performance, but also in the fact that they are generally more cost-effective than PCD tools. They are also a particularly good choice when machining other materials in addition to aluminum, as they are suitable for a wider range of applications.

Geometry and surface technology as the key to performance

The tool geometry is decisive for the quality of machining. Our milling cutters have precisely ground cutting edges, a sharp point and defined cutting edge rounding. Internal cooling channels enable an efficient supply of cooling lubricant, while flat helix angles and uneven helix pitches minimize vibrations and improve chip breaking at the same time. The chip chambers have also been specially designed for aluminum alloys to ensure reliable chip evacuation. The strength of our tools is particularly evident when drilling: The specifically designed MQL chamfer on the cutting edges optimally supports aerosol lubrication and makes the tools particularly efficient in combination with modern MQL systems.

A decisive contribution to tool performance comes from surface technology. In order to meet the high demands placed on PCD and solid carbide tools, HAM has developed Hybrid Surface Finish, or HSF for short, a hybrid and technologically highly complex solution. This produces a defined surface finish while simultaneously homogenizing the cutting edge. In combination with a precisely coordinated grinding quality, this creates a high-performance overall system.

For tools with shank diameters up to 32 millimeters, we apply PVD hard coatings such as TiN, TiAlN, TiNAlOx, or AlOx. The HSF process ensures mirror-smooth surfaces on carbide and PCD, for diameters between 0.5 and 32 millimetres. Depending on the application, defined cutting edge preparations of 4 to 20 µm are achieved. The tool’s meticulous design comes to life only when all its properties are combined optimally, unleashing its full potential.

Machining aluminum – exploiting potential, mastering challenges

Machining aluminum is more than just a routine production step. Different alloys, complex material properties and process-specific requirements demand a high level of expertise. If you want to manufacture economically and reproducibly, you need to have the entire machining process under control – from material selection and the optimum cooling strategy to the precise coordination of machine, clamping and CAM programming. The high quality that modern applications require today can only be achieved if all factors are interlinked.

With our many years of experience in aluminum machining and our highly developed tool solutions – from polycrystalline diamond to finely tuned solid carbide – we not only offer individual components, but also sophisticated overall solutions. Technologically leading geometries, specially developed surface treatments such as HSF and perfectly coordinated coating concepts make our tools the first choice for demanding production tasks. Anyone who wants to machine aluminum efficiently and reliably benefits from our expertise down to the smallest detail.

Practical application

In our workshop “Zerspanung ALU – Best of HAMmer”, we showed how theory and practice can be optimally combined. We machined a component made from the high-strength aluminum alloy EN AW-2017A. This alloy is an age-hardenable material that develops its full strength potential after targeted heat treatment, such as solution annealing with subsequent cold ageing. It plays a key role in the aerospace and defense industry in particular due to its high mechanical strength and good machinability.

The workpiece, measuring 200 x 100 x 25 millimetres, was machined on a Hermle C12U, controlled by a Heidenhain TNC 640. We used a zero-point clamping system from LANG to ensure reliable and repeatable clamping. In combination with a precise tool holder from Diebold based on HSK-A63, a high level of stability was guaranteed.Milling was performed with targeted use of minimum quantity lubrication and classic cooling lubricant, ensuring optimal chip removal and maximizing tool life based on the machining area.

When everything works together, it shows how powerful aluminum can be in the right environment.