Laser Cutting of Metal
Metal is perhaps the most common material that is cut with lasers. There are over one hundred different types of metal, and hundreds of industries around the world use some type of metal, whether at the beginning or at the end of the manufacturing process.
Finding a process that can cut metal efficiently to keep up with the ever-growing demand for products, as well as reducing costs and maintaining only the highest level of safety can seem a tall order. The invention of the laser back in the 1960s, and its development into fiber lasers that are commonly used today, ticked all of these boxes.
In the article below we have covered the cutting of metal with lasers in much greater depth, looking at specific examples and applications, as well as which type of laser is best suited for this task.
Which type of laser cutting should you use to cut metal?
There are three types of laser cutting processes that you can use to cut metal; gas laser cutting, crystal laser cutting and fiber laser cutting. Gas laser cutting is conducted with a carbon dioxide or nitrogen mixture, and crystal laser cutting, is conducted using nd:YAG (neodymium-doped yttrium aluminium garnet) and nd:YVO (neodymium-doped yttrium ortho-vanadate) crystals. These two laser processes have been around much longer than fiber laser cutting, and have a history dating back to the 1960s, whereas fiber laser cutting is a relatively new process.
To put it simply, each of the three laser cutting processes can be used to cut metal, although gas laser cutting wasn’t always able to do this so well, but we’ve compared them all here.
Crystal laser cutting is good for cutting metal, but you would typically only use this process where high power is needed, probably for very thick metal. A crystal laser cutting machine is expensive, run on costly pump diodes, so should you need replacement parts this can start to weigh down heavily on your bank balance! A crystal laser cutting machine has a shorter service life than the other types of laser cutting machines, at around 8,000 to 15,000 hours.
Gas laser cutting machines have improved greatly over the last few years, and are now much more adept at cutting metal. It is the most common form of laser cutting process, and is cheaper to run than a crystal laser cutting setup.
However, comparing this to the fiber laser cutting process, the latter is more advantageous when it comes to cutting metal. A gas laser cutting machine can generally cut quicker than a fiber laser cutting machine, but this only applies to thick metals; for thin metals fiber laser cutting is quicker.
Furthermore, when using a gas laser cutting machine, there is a much higher risk of damaging the metals that you are working with. If the gas isn’t completely pure, then the metals may be oxidised and take on a yellow tint in colour. Also, gas laser cutters can’t work well with reflective metals, as the beam is reflected back at the machine, whereas a fiber laser cutting machine doesn’t have this problem. This is known as flashback damage.
Alongside this, a fiber laser is much less expensive to run, having a long service life of around 25,000 hours, rarely needing maintenance, and only requiring cheap replacement parts should they be needed.
Several businesses and manufacturing plants were interviewed on their thoughts of gas laser cutters vs fiber laser cutters, and it was agreed that the fiber laser cutting setup was the more favourable of the two.
Although it was said that gas laser cutting is better for heavier plates of metal, fiber laser cutting is generally faster, uses much less power, can work with reflective metals, and has 50% longer servicing intervals as well as half the amount of servicing costs.
This is why we’ve chosen to manufacture and develop fiber lasers here at SPI Lasers, with both Pulsed Fiber Lasers and Continuous Wave Fiber Lasers machines. We would therefore recommend fiber laser cutting for your metal applications!
Some examples of the laser cutting of metal
Now that we have looked at the different laser processes and their effect on metal, we will now examine specific examples of the laser cutting of metal.
The laser cutting of reflective metals
As mentioned above, some cutting lasers have trouble with cutting reflective metals due to flashback damage, where the laser beam is reflected back into the lasers Beam Delivery Optic (BDO) itself. However, reflective metals are commonly found in the manufacturing process, and it is important to be able to cut them efficiently and effectively. Reflective metals are metals such as gold and silver.
To demonstrate just how well an SPI fiber laser can cut reflective metals, we wanted to create complex and intricate shapes. We created a replica of Tower Bridge, and two SPI Lasers’ pets; an eagle and a dragon! You can read more on the making of Tower Bridge and the dragon here.
The laser cutting of steel
Steel is one of the most common metals used by industries around the world, and so is one of the most crucial to manufacturing processes. Whether it is thick steel or thin steel, a fiber laser will have no problem working with it. With the high power that these machines pack, you’ll find it can run through steel very quickly.
Here we have looked at the laser cutting of mild steel, at a thickness of between 0.5mm to 1.9mm, that can be cut at speeds of up to 10m/min. You’ll commonly find this type of steel in a range of industries, such as the automotive and aerospace industries, and is key to forming the bodies and structures of the vehicle and aircraft.
You can see two videos of the laser cutting of steel here:
The laser cutting of copper
Copper is an extremely useful metal thanks to its conductive abilities for electrical currents, alongside other reflective metals such as gold and silver. If the metal is thinner than 0.5mm, then it can be cut using a fiber laser cutting machine with just one pass. Anything above this, it may need multiple passes, but will still deliver a smooth cut either way.
We have written about the laser cutting of copper here, to show the result of the cutting of a butterfly shape into a thin plate of copper. You can also see a video demonstration here: redENERGY G4 Pulsed Fiber Laser Cutting & Marking 0.3mm & 0.9mm Copper.
The laser cutting of aluminium foil
Aluminium foil is a metal that has uses for a range of industries, perhaps most commonly seen in the packaging industry. We have written about the quick cut of thin aluminium foil here, where we found that the fastest speed was at 100kHz.
It is important that aluminium is cut using only one pulse, as it was found that repeated pulses could damage the metal.
The laser cutting of silver
Silver is an extremely widely used metal, seen in both industrial and commercial settings for things such as jewellery, electronics, or energy devices. We’ve discussed more on the laser cutting of silver here, as well as looking at a specific example of the laser cutting of 1mm thick silver here.
Looking for more information on laser cutting?
Although this article has focused on the comprehensive laser cutting of metal, the process is capable of working with an almost limitless amount of materials.
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