Metal laser cutting machines explained
Metals happen to be one of the toughest materials to utilize in the laser industry. More often than not, newcomers in the laser marking industry often assume that a fiber laser marker can do both cutting and marking. But this is not entirely true. A typical metal laser cutter has characteristics different from that of a fiber laser marker. One major difference between these two diverse machines is the intensity/focus of the laser source. Usually, a fiber laser marker has a laser wavelength between 800nm to 2200nm. But a metal laser cutter has a wavelength between 9000nm-11000nm, meaning it’s far more powerful. This shows the penetration ability of both machines when in use.
Can a Fiber Laser Cut Metal?
Yes, you can laser cut metals with a fiber laser, however, it would have to be an extremely potent fiber source of around 2000W. You cannot laser cut any metal with a standard fiber laser of 20W to 50W. This means that laser cutting metal is only possible for big businesses. A fiber laser can penetrate metals more easily than a CO2 laser because the focal point is much smaller, meaning the laser beam is denser and more concentrated. Even so, standard fiber sources up to 50W do not have enough power to laser cut metal.
What Power of Fiber Laser Can Cut Metal?
In order to laser cut metals with a fiber laser source, it would have to be an industrial fiber laser of at least 2000W, or 2kW. Such powerful metal laser cutting machines are extremely expensive, in the range $60,000 to $100,000 and up, making them out of reach for most small businesses.
Therefore, to ensure correctness and efficiency, a standard fiber laser marker should be used strictly for laser marking. This is because to cut or even engrave metal with a 50W fiber laser marker, you would have to spend so much time due to numerous passes of the metal through the machine. It is for this reason that fiber laser markers are restricted to marking metal and not used as metal laser cutter. And as a small business, you should highly consider adding a fiber laser marker to your machine inventory due to its versatility, quickness, and affordability. You could complete numerous projects like custom tumblers, jewelry, medals, and more. Therefore, a CO2 laser engraver would come in handy as a metal laser cutter.
If you’re looking to create laser cut metal signs, keep in mind that you cannot laser cut metal yourself with a fiber laser marker. You’ll need to buy the metal sheets pre-cut to size before adding customization for each client.
A quick glance into Fiber Laser Markers
CO2 laser engravers were the first to be introduced in the laser industry, but the need for fiber laser markers arose due to the specific need for metal marking and not only cutting. It was not until the 1990s before this machine type was shot into the limelight. A fiber laser is produced from a laser source which is a mix of silica glass and rare earth metals. For this reason, fiber lasers are referred to as solid-state lasers and can last up to 100,000 hours in operation before needing routine maintenance. Here's a rundown of the steps involved in creating a fiber laser beam:
- Transformation of electricity into light or photons.
- Created photons are pumped into a fiber optic cable and guided to form a single light beam.
- Single light beam travelling in the fiber optic cable enters a laser cavity to become amplified into a laser beam.
- A specific wavelength of the laser beam is formed based on the laser cavity doping element.
- Laser beam is shaped and ready to use for marking.
Top 5 Popular Metals for Laser Marking
When setting out to mark a metal, having the right machine such as that from OMTech would do you a lot of good. It would interest you to know that there are endless possibilities to the designs you can mark on any metal of your choice. But out of all the metals you could possibly mark, some standout as the most popular and rightfully so. With that said, let's dive in:
Aluminum is by far one of the most used metals throughout laser businesses due to its lightweight and durability. It comes in various forms such as bare, anodized, and cast. You would find that anodized Aluminum is quicker to turn white when marked with a lower beam intensity. If it's bare or cast aluminum, a darker marking is best and a higher beam intensity would do the job. In any case, it’s imperative to always keep your marking as deep as possible with the right contrast for aesthetic appeal.
After Aluminum, Stainless steel is the most commonly used, especially in areas of high hygienic requirements. Various projects that can be done with stainless steel include kitchenware, cutleries, accessories, and more. This metal supports all forms of marking such as engraving, etching, and even annealing. For this reason, it's very versatile and adaptive to whatever marking parameters it is subjected to without getting damaged. When engraved or etched, it can withstand the high temperature that accompanies the process. Yet, a great contrast is achieved when the marking is done.
Silver and Gold
When it comes to jewelry, these two precious metals definitely come to mind. They are quite soft and fragile, hence, they must be handled with care when laser marking. During marking, the top surface of silver is known to oxidize quickly while that of gold is more stable and this makes it easier to mark. With little laser power, you can anneal Gold with a good contrast. Due to the soft nature of these metals, engraving and etching might be harsh on them, so it's better to anneal. When you mark a surface by annealing, minimal material is taken off the material’s surface.
This is a lightweight alloy that has special usage in the aerospace, automotive and medical industries. It's combination of durability, strength, and lightweight makes it completely stand out. For the medical industry, the marking should be done in a way that it doesn't give room for contamination.
Engraving and etching is fine for medical purposes while annealing is perfect for aerospace purposes. This is because in the aerospace industry, the titanium parts are subjected to fatigue testing to ensure no compromise of the part when in service. For this reason, structural damage due to exposure to excessive heat during marking must be limited. This shows that Titanium must be carefully marked and attention should be paid to its specific area of application.
Tungsten and Carbide
One common property of this metal is that their hardness is second to diamond with a Mohs hardness of 9. Tungsten is naturally lighter in color than Carbide, hence, you should use a higher intensity fiber laser to mark your design. If possible, the marking should be an annealed one for proper contrasting. Area of application of these metals include cutting tools, abrasives, piercing tools and some kinds of jewelry.