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.

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Laser cutting can create many interesting shapes from metal, such as is shown in the image above

Which type of laser should you use to cut metal?

There are three types of cutting processes that you can use to cut metal with a laser; gas, crystal and fiber . Gas cutting is conducted with a carbon dioxide or nitrogen mixture, and crystal cutting, is conducted using nd:YAG (neodymium-doped yttrium aluminium garnet) and nd:YVO (neodymium-doped yttrium ortho-vanadate) crystals. These two processes have been around much longer than fiber-based cutting with a laser, and have a history dating back to the 1960s, whereas fiber laser are a relatively new process.

To put it simply, each of the three cutting processes can be used to cut metal, although gas based methods wasn’t always able to do this so well, but we’ve compared them all here.

Crystal lasers are 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 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! Crystal lasers have a shorter service life than the other types of laser machines, at around 8,000 to 15,000 hours.

Gas laser machines have improved greatly over the last few years, and are now much more adept at cutting metal. It is the most common laser cutting process, and is cheaper to operate than a crystal laser .

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, but this only applies to thick metals; for thin metals fiber lasers are quicker.

Furthermore, when using a gas laser, 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 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 setup was the more favourable of the two.

Although it was said that gas lasers are better for heavier plates of metal, fiber lasers are 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 and Continuous Wave (CW) machines. We would therefore recommend fiber lasers for your metal applications!

Some examples laser metal cutting

Now that we have looked at the different processes and their effect on metal, we will now examine specific examples of the laser cutting of metal.

Cutting of reflective metals

As mentioned above, some 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.

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, fiber lasers 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 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:

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 fiber lasers 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.

Copper can be cut relatively easily with laser cutting

Copper can be cut relatively easily with laser cutting

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.

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 cutting of silver with lasers here, as well as looking at a specific example of the laser cutting of 1mm thick silver here.

Looking for more information on cutting with lasers?

Although this article has focused on the cutting metal, the process is capable of working with an almost limitless amount of materials.

With a vast number of advantages, laser cutting has come to find itself used in numerous industries around the world, including the semiconductor, electronics and medical industries.

Help from SPI Lasers

If you have more questions regarding cutting with lasers and how it works, please get in contact with us here.

 

Image credits: Sergei Akulich, Kaboompics // Karolina, Athena Lam and Maximilian Frank

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