Laser CNC Engraving Metal

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Laser CNC Engraving Metal

In the past #lasers and metals have not mixed very well. While a laser does produce high amounts of heat suitable for cutting or engraving it is still, at its core, light. Anyone who has ever walked through a full parking lot of shiny cars on a hot, sunny day without their sunglasses knows that metal reflects light very efficiently. Many individuals know that laser cutters traditionally do not work on metal and would not attempt any kind of metalworking project using a laser. However, there are multiple types of lasers and some do work well enough with metals for engraving projects.

CNC Laser Engraving Metal

CNC Laser metal cut

One of the first gas #laser invented was the CO2 laser and it is still one of the most common lasers used today. This type of lasers work on some metals but not all, as some metals reflect the laser beam too much for it to be effective on metal projects. One type of the metals that works well with a CO2 laser is anodized aluminum. Anodized aluminum comes in several different colors and you will observe different effects depending on what color the metal is. For example, black anodized aluminum turns white when engraving with a laser while red anodized aluminum turns light pink. You can intensify the color with a second pass and get a whiter sheen but you will usually not be able to completely remove the original color created by the initial cut. Anodized aluminum should be cut at low power, high speed setting in order to generate crisp, clean engravings. Using too much power can distort engravings and result in images that have been burned too much during the cutting process.

 CNC Laser Engraving Metal

CNC Laser cut

Painted brass is another metal that works well. Do not use unpainted brass with a CO2 laser; it will reflect the beam and you will likely get hurt. The laser will remove the coating from brass that has been painted, exposing the brass beneath for appealing visual effects. You can also use brass-coated steel. Like with painted brass, you will be removing paint to expose the brass beneath. Brass-coated steel just has a thin layer of brass over steel instead of being made from pure brass. The polished brass that you expose with your #laser is protected by the lacquer, preventing the brass from being oxidized and keeping it bright and shiny for many years. If you do not know whether your material is painted brass or brass-coated steel you can test it with a magnet. Magnets will stick to brass-coated steel but not to painted brass since solid brass does not have a sufficient magnetic field to attract and hold a magnet.
For other metals you can use an Yb: Fiber Laser, a fiber laser that uses the element ytterbium. Fiber lasers have several distinct advantages over more traditional lasers. The key component that makes them suitable for laser engraving is that the light used is already coupled into a flexible fiber, allowing it to be delivered to a movable focusing element easily. This is what makes it much more difficult for metal to reflect the beam, making this type of #laser safe to use with more types of metals. Fiber lasers also have a very high power output and can have active regions up to several kilometers in length. The fiber’s high surface area to volume ratio allows for continuous output at the kilowatt level, resulting in efficient cooling. Because fibers can be bent, unlike rod or gas lasers, they are usually very compact machines. The pulses that the lasers generate operate within nanoseconds, further making fiber lasers well-suited for metal engraving projects.

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Article Name
Laser CNC Engraving Metal
Description
In the past #lasers and metals have not mixed very well. While a laser does produce high amounts of heat suitable for cutting or engraving it is still, at its core
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