Start Here November '21

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T he term "laser" is widely used in the engraving and cutting industry, but many may not know that it's an acronym for "light amplification by the stimulated emission of radiation." Sounds cool, doesn't it? A laser is a special kind of light that has proven to be useful for many different applications. Most people also don't realize that there are different types of lasers. You often hear the terms "fiber," "CO 2 ," or "UV diode" laser as well as many others. In the simplest form, these terms are typically related to the tech- nology associated with how the laser light is produced. For example, in the case of the fiber laser, it is a "solid-state" device that uses low power laser diodes to pump light into fiber optics. These fibers are then combined to generate the useful laser beam. A CO 2 laser uses carbon dioxide "gas" inside of a glass or metal tube that is used to create the laser beam. Think of this as a special kind of lightbulb. Each of these types of lasers produces a different wavelength (or color) of light. For instance, the fiber laser produces a 1064nM wavelength, and the CO 2 is typically either a 9.3uM or 10.6uM wavelength. These colors fall into the near infrared range, whereas UV lasers produce ultra violet light, which is on the other end of the visible spectrum. CO2 and Fiber Lasers Most businesses in the graphics industry are familiar with CO 2 lasers and likely even have one or more in their shop already. If so, it's probably a flatbed machine from one of the many industry brands. It's important to note that the different colors of light are the main reason that different materials react differently depending on whether it's a fiber or CO 2 laser. Fiber lasers tend to react best with metals, ceramic, and many industrial plastics. On the other hand, CO 2 lasers tend to be better suited for organics such as wood and paper as well as acrylics, powder coatings, etc. There are many exceptions and some common areas where both do well, such as when marking anodized aluminum. Fiber lasers are extremely effective at deep engraving metals such as aluminum, stainless steel, titanium, gold and silver alloys, etc. This makes them particularly well suited for marking on knives, awards, firearms, jewelry, etc. Lower-power CO 2 systems on the other hand are extremely effective at marking and cutting wood, paper, acrylics, and many fabrics. They are also effective at removing many types of paints and powder coatings. It's important to note that not only are there differences between a fiber and CO 2 laser, but there are differences in how the laser beam is delivered to the item being cut or engraved. As mentioned already, most people are familiar with a flatbed or what would be referred to as a gantry-style laser. With this type of system, the beam is delivered using a gantry system that carries beam routing mirrors and a focusing lens assembly moving over the item to be cut. A flatbed laser is especially good at cutting because the beam is delivered from above the item to be cut in a vertical ori- entation that produces relatively straight cuts. This type of cut- ting machine can also be used for engraving, but because of the relatively large and heavy gantry and lens, engraving tends to be a bit slow. A flatbed laser can be thought of as a cutting machine that also marks (engraves). A flatbed laser can be configured with CO 2 or fiber, or both. On the other hand, another type of popular approach to engraving is a galvanometer (galvo)-based laser. Galvo-based systems can be used with either fiber or CO 2 lasers, but typically both. This type of system is dif- ferent from a gantry system because instead of moving a large lens over the work piece, the system uses moving mir- rors to deliver the beam. A galvo system is especially fast at marking since moving small mirrors is much faster than moving a heavy lens/gantry. Marking speeds are sometimes up to 10 times faster than when using a flatbed. Although these systems can be used for cutting, because the beams tend to hit the part at angles, cuts are not as straight as with a gantry. So, unless the material to be cut is paper or fabric, the results are not as desirable as with a gantry. You can think of a galvo system as a marking (engraving) machine that also cuts. I like to make this distinction as it helps customers decide what type of system best suits the applications they are serving. You can see that there are quite a few things to know about fiber and CO 2 lasers as well as flatbed or galvos. Many shops have both of these systems since each brings advantages that can help grow their business. What Kind of Laser is Right for You? By Tom Tamburrini CEO, Radian Laser Systems LLC Do you know what laser specifications you need? Engraving pro Bob Hagel offers some insight on laser table size, power output, and maintenance at Each type of laser produces a different wavelength (or color) of light. (Images courtesy Tom Tamburrini) Lower-power CO 2 systems are extremely effective at marking and cutting wood, paper, acrylics, and many fabrics. A galvo system is different from a gantry system because instead of moving a large lens over the work piece, the system uses moving mirrors to deliver the beam. 64 S T A R T H E R E 2 0 2 1

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