Aluminium laser cutting is essential for cutting complex shapes with high quality. Because of the difficulty of the job, many manufacturers avoid it. To overcome the challenges presented by aluminium laser cutting, you must have the necessary knowledge and experience.
The Benefits of Laser Cutting Aluminium
Aluminium is widely used in the manufacturing industry to make a variety of products such as cans, foils, aircraft parts, and window frames, so there is an increasing demand for cutting aluminium materials into various shapes. Metal shears, jigsaws, circular saws, CNC machines, and laser cutters are some of the aluminum-cutting tools available on the market. Among all of these tools and methods, laser cutting is the most appropriate and advantageous. Here are four advantages of using a laser to cut aluminium.
- Precision Cutting: The first advantage of laser cutting aluminium is that it produces precise cuts. Standard laser cutting machines use laser beams to cut aluminium sheets. As a result, it is capable of producing small holes, sharp cuts, and high-quality edges. When compared to other cutting processes, it is clear that they cannot match the accuracy of laser cutting machines. The machines have an accuracy of ±0.0005 inches.
- Lower Cost: When compared to other cutting processes like chemical etching, laser cutting is less expensive overall, and because it is a non-contact process that uses a laser beam, the tools last longer. Another advantage of laser cutting machines is their long-term cost-effectiveness.
- Customisable Cutting Shapes: Cutting aluminium sheet with a laser cutter enables highly customised jobs without the need for additional tooling fees or upfront costs. You simply load the laser cutting file containing the cutting/engraving details into the machine. The machine will handle the rest, regardless of how complex the design or shape is!
- Fast and Repeatable: A laser cutter outperforms metal shears, circular saws, and other cutting tools in terms of speed. Another advantage of laser cutting is that it can complete the job in seconds. In addition, the entire process is highly repeatable. Simply add the cutting file and adjust the laser cutter’s settings. It will then cut out the number of aluminium designs/shapes you specify with little human intervention.
Why is Aluminium Cutting a Challenge?
Although laser cutting is the best way to process aluminium, many processors and manufacturers are still hesitant to use it due to the 3 challenges listed below.
Reflective materials
Cutting aluminium isn’t always an easy task. Because of the material’s reflective properties, a laser beam may bounce back and damage the laser cutter. Stainless steel is notorious for similar reasons, but aluminium outperforms the AISI grades in cutting difficulty.
When discussing these topics, it is common to mention coating the material with something non-reflective. Of course, it doesn’t lower the risk. When the coating is pierced and the aluminium melts, the highly reflective surface is revealed.
These issues are more common with aluminium grades that contain fewer alloying elements, such as AW 1050. The elements reduce the reflectivity of aluminium alloys.
Thermal Conductivity
Laser beams vaporise materials, which they then cut. However, this can be problematic if the material has a high thermal conductivity. Aluminium is one of the materials capable of absorbing and dissipating heat. As a result, when the laser beam contacts the aluminium surface, it rapidly cools, preventing the laser cutting machine from reaching the high temperatures required for melting and vaporisation.
In fibre laser cutting, the laser quickly contacts the aluminium surface, allowing it to melt quickly rather than dissipate into the surrounding environment.
Upfront Costs
To cut seamless, high-quality aluminium, use a high-powered fibre laser cutting machine or a CO2 laser cutting machine. This means that you’ll have to spend a lot of money on equipment. However, in the long run, this can save you money, time, and effort.
How to Improve Laser Cutting of Aluminium
Although laser cutting of aluminium presents challenges, with the increasing demand for aluminium products from related industries and consumers’ increasing expectations for the quality of aluminium products, manufacturers are paying close attention to how to use laser cutting of aluminium to achieve better results.
Cutting Thickness
Aluminium laser cutting is suitable for materials as thick as 6-8 mm. Above this thickness, the quality suffers significantly, and the material must be further processed. We do not recommend laser cutting materials larger than 20 mm unless you use a laser cutting machine with more than 15000W.
Water jet is an effective cutting technology for thicknesses greater than 8 mm. Water jet cutting is a better option for thick aluminium plates due to its speed, quality, and low hourly rate. Although the cutting kerfs in these technologies differ, the larger kerf will not cause problems with thick materials.
Cutting Speed
Cutting speed is another factor that can help you achieve smooth surfaces and delicate edges. When working with aluminium, fast-cutting machines are always preferred. However, cutting speed alone is insufficient to cut aluminium properly. Combining high laser power and fast cutting speeds yields the best results. The laser cutting machine’s cutting speed must also be adjusted in accordance with the thickness of the aluminium. Also, keep in mind that the operating speed will vary depending on whether you are using a CO2 laser or a fibre laser!
Laser cutting machines with low cutting speeds can cause cracks in aluminium sheets. Similarly, very high cutting speeds can produce rough edges. As a result, selecting the appropriate cutting speed is critical for this process!
Assist Gas
The use of assist gas in a laser cutting machine eliminates waste generated during the cutting process. Furthermore, it keeps the cutting head from overheating and promotes high-quality cuts. Using various assist gases, such as oxygen, air, argon, nitrogen, and so on, will have varying effects on the processing. However, please use oxygen with caution, as it can cause oxidation of the aluminium sheet. Nitrogen is the preferred assist gas for optimal results with no oxidation and smooth edges.
Reflection detector
Aluminium and other reflective materials can cause damage to the machine’s laser module. As previously stated, fibre laser cutting machines can solve the reflection problem. However, many people continue to use high-power CO2 or ND:YAG laser cutting machines to cut reflective materials.
To prevent reflections from damaging the laser module and interfering with the cutting process, we recommend using a machine with a reflection detector. All modern laser cutting machines manufactured by reputable brands typically include a reflection detector. This feature can detect if a significant portion of the laser beam is returning to the laser head via reflection. As a result, once the amount of reflected laser beam reaches a certain threshold, the machine will automatically shut down to avoid damage.
If you intend to use a CO2 or ND:YAG machine, you must purchase one with a built-in reflection detector. This will protect your machine from damage or fire caused by reflected lasers!
Selecting the Right Laser Cutting Machine
First and foremost, laser cutting is still the best way to cut aluminium. As our partners have demonstrated, laser cutting is quick and, when combined with the appropriate expertise, can result in a burr-free cutting process. It is still necessary to consider the grade of aluminium. The higher the grade of aluminium, with more alloying elements, the easier it is to cut.
Another thing to consider: does the manufacturer use a fibre laser or a CO2 laser? Fibre lasers are better suited to cutting reflective materials due to their construction. CO2 lasers contain a series of mirrors. The structure is more vulnerable to damage from reflected laser beams. The same is true for flat part cutting and using laser cutting services on tubes.
The more powerful, the better the outcome. If you’re still thinking about using a CO2 laser for aluminium cutting, keep in mind that they have a much lower power output despite similar parameters. We recommend using a powerful fibre laser. It can produce good results if used correctly.
Reflections on aluminium can be eliminated by using the proper focussing distance. Keeping the focus away from the material also helps to reduce the amount of dross.
Conclusion
Laser cutting machines are extremely versatile when working with a variety of materials. However, not all laser machines can be used with any material. Laser cutters are optimised for various materials.
The most popular options for cutting aluminium are fibre laser cutters or high-powered CO2 lasers. We’ve provided a wealth of resources to help you determine which laser cutter is best for you and how to easily cut aluminium!
During the aluminum cutting process, there may be problems such as consumable loss. If you need to replace consumables, you can go to the Pendstar shop for the full range of the original laser cutting machine parts.
