Anodised aluminium is a versatile material that you will find in many metal fabrication applications. It’s relatively cheap to source and looks attractive – hence, it is a common choice for industrial and cosmetic uses. But which processes are suitable for anodised aluminium?
Anodised aluminium can be cut with a CO2 or fibre laser. Anodised aluminium is suitable for laser etching, but isn’t ideal for engraving. Because anodised aluminium is a relatively soft metal, lasers don’t have an issue etching it but will struggle to engrave without damaging it.
With such a wide variety of applications, manufacturers need to understand the properties of anodised aluminium and what services it is suitable for. To learn more about anodised aluminium, and the processes involved in laser cutting, engraving and etching this material, keep reading this article.
What Is Anodised Aluminium?
Anodised aluminium is aluminium that has undergone an electrolytic passivation process called anodising. During anodising, the aluminium acts as an anode within the electronic cell. This process thickens the natural oxide layer on the aluminium’s surface, resulting in a hard and durable finish.
The anodising process alters the microscopic texture and crystal structure of the surface of the aluminium. Anodised coating is often porous, so a sealing process is also usually applied.
Anodising has several benefits, including:
- Increasing the material’s resistance to wear-and-tear and corrosion
- Preparing the material so that primers, paints, and glues can adhere to it more easily
- Gives a more desirable cosmetic look
- Preventing galling of threaded components
In addition, anodisation is considered an eco-friendly metal finishing process. The byproducts of this process contain only minimal amounts of halogens, heavy metals, and volatile organic compounds (VOC). Even the anodising wastes such as aluminium hydroxide and aluminium sulphate are recyclable as they can be used as ingredients for cosmetics, newsprint, fertiliser, or wastewater treatment.
How Is Aluminium Anodised?
To anodise aluminium, the aluminium workpiece is first immersed into an acid electrolyte bath where an electric current is then passed through the bath. A cathode inside the anodising tank reacts with the aluminium, which acts as an anode. Oxygen ions are then produced from the electrolyte to fuse with the aluminium atoms of the workpiece’s surface.
Anodising is actually a sped-up process of oxidation, which is a naturally occurring process.
Can You Laser Cut Anodised Aluminium?
Yes, you can cut anodised aluminium using a CO2 or fibre laser. Aluminium can be more difficult to cut due to its softness, reflective surface and heat conductivity, but clean results can still be produced with a CO2 or fibre laser.
Because of their ability to make precise cuts, lasers are typically used to cut holes and intricate shapes when fabricating metals, including anodised aluminium. Anodised aluminium can be cut effectively using a fibre laser or CO2 laser cutter due to the softness of the metal. This produces a clean cut without the concern of aluminium shavings or jagged edges, and laser cutting also reduces material waste.
Plasma cutting is also effective on aluminium, but achieves less precise and clean results, and can’t create intricate designs in the way the laser cutting can.
The key to laser cutting anodised aluminium successfully is using a quick and efficient laser, as aluminium’s softness and thermal conductivity can lead to molten metal accumulation and produce a rough edge. For that reason, high quality equipment and technique are both important when laser cutting aluminium.
Can You Laser Etch & Engrave Anodised Aluminium?
While you can laser etch anodised aluminium, it’s not advisable to engrave anodised aluminium, because it is far too soft of a material to engrave effectively.
Laser etching is the preferred method of marking designs and patterns on anodised aluminium. Laser marking techniques can be used by some workshops to etch anodised aluminium surfaces like merchandise and promotional items.
Etching can also be used to mark components for traceability through the metal fabrication process. The laser etching contrasts against the anodising colour, which makes the prints and designs stand out easily. As a result, laser etching is used for engraving QR codes, bar codes, serial numbers and other fine prints.
Laser etching can even work on an aluminium workpiece with a treatment on its surface that predates the anodising. The laser generates enough power to etch the most resistant marks on aluminium, ensuring that these markings maintain high readability before or after surface treatments. This is why etching is preferred to mark parts for assembly.
Is Anodised Aluminium Better Than Aluminium?
Anodised aluminium is often a better choice than aluminium because when it is anodised, it becomes much stronger and more resistant to rusting and corrosion. Anodised aluminium is also less conductive, which makes it a good choice for fabrication using tools like lasers.
However, aluminium is often less expensive than anodised aluminium, which makes it a better choice if budget is a primary concern.
Can Aluminium Be Cut With a Laser?
Yes, aluminium can be cut with a laser, but only if you are using a CO2 or fibre laser cutter Even though aluminium is a reflective surface that can cause problems for some lasers, CO2 and fibre lasers will both be able to cut through the metal without any trouble. A CO2 laser can also etch aluminium, while a fibre laser can engrave it.
How Thick of Aluminium Can You Laser Cut?
A piece of aluminium 40mm thick can be cut by a 10,000 watt laser. The thickness of the laser cutter will determine how thick of a sheet of aluminium you can cut, for example, a 4,000 watt laser cutter can only cut sheets of aluminium that are 20mm thick or less. If your sheet of aluminium is thicker than 40mm, it may be worth finding a different way to cut it, other than using a laser cutter.
Can a CO2 Laser Cut Aluminium?
Yes, a CO2 laser is capable of cutting through aluminium, even though it is a reflective material. The laser will be able to easily cut through the metal depending on the strength of the laser and the thickness of the metal. When using a CO2 laser to cut aluminium, it is important to use a lens that can protect the beam from reflecting off of the metal, as it can damage the laser.
What Type of Laser Will Etch Aluminium?
Fibre lasers are one of the few lasers recommended for laser etching aluminium, because the heat and control of the fibre laser won’t immediately ruin the quality of the metal, like other lasers would.
Fibre laser systems produce the ideal wavelength needed for marking metals, including those that are softer than steel. However, the type of laser technology you need depends on the exact material and design you want to engrave.
Disclaimer: This article is published in good faith and for general informational purposes only. Kanyana Engineering does not make any warranties about the ongoing completeness and reliability of this information. Always seek specific advice on your metal fabrication project to ensure all variables are taken into consideration.
Graham Dawe is the Managing Director and Works Manager of Kanyana Engineering. With decades of experience in the metal fabrication industry, he is dedicated to keeping Kanyana at the forefront of the sector’s technological growth. Looking beyond the process itself to holistic, integrated CAD, CAM and MRP solutions, Graham believes Australian manufacturing has an enduring place on the global stage. In Kanyana Engineering’s state-of-the-art workshop in Mandurah, WA, Graham delivers an exceptional standard of work for commercial, industrial and government clients alike.