Laser Engraving and Marking

Before you can begin your laser engraving and marking project, there are a few things you must know. First, you must setup your laser in the correct alignment. Second, you must learn the proper settings for the material you are engraving. Laser settings differ for nearly every material, so be sure to research your material. After all, a laser is only as good as its settings. Here are some helpful tips to get you started.

Ablation

The term “laser” stands for Light Amplification by Stimulated Emission of Radiation, and it is a powerful light source that vaporises materials by causing a discoloration on the surface of the component. High contrast marks can be made with lasers because of the precise control of parameters. This technology is used for a variety of applications, including engraving, marking, and welding.

There are two primary types of laser marking: etching and engraving. The latter is often faster and causes less damage to the material than engraving, but it is not recommended for safety-critical parts. Engraving is a form of machining where the laser beam vaporizes the top coating of a material, leaving behind an indentation. In contrast, ablation removes top coatings from metals, including powder-coated metals, anodized metals, and plated metals.

Dark marking

Laser etching and engraving both use the same settings to create a dark mark on metal. The laser will oxidize the material, creating a unique pattern on the surface. It also anneals the material, which is a great benefit for companies that produce expensive items. These are two popular ways to add custom markings to metal. However, each method has its own drawbacks. To learn more, read on.

The main differences between laser marking and engraving are based on the parameters used. The pulse frequency, laser power and focused laser spot size are among the key parameters used in these processes. Each technique will affect the part’s surface in different ways. Stain marking, for example, involves heating the part’s surface enough to create a layer of oxide. The part can also be marked in colors other than black. With a little work, other colors can appear on the surface.

Annealed mark

In addition to laser engraving, annealed metal is resistant to corrosion and bacteria. Compared to laser engraving, annealed metal is hygienic and easy to clean. This is especially important for products that are susceptible to rust or bacterial buildup. Medical instruments are commonly made of titanium and stainless steel. They must have a unique identifier (UDI) to avoid tampering and contamination.

The annealed process changes the surface of the metal to a blackish color. This process is necessary for firearm serial numbers, because the metal must be engraved deeply. Some steels, such as carbon steel, will not anneal, and are incapable of being marked. Stainless steel and titanium are common metals that will anneal easily. Laser engraving is particularly effective on these metals, which can be perfect black.

Raster engraving

In most cases, laser engraving and marking use the same technique, although the exact method varies depending on the material. The surface of the object needs to be in the focal plane of the laser optical system. The focal point is typically a fraction of a millimetre in size. A laser beam passing over the surface changes the surface of the object by delivering energy that changes its properties. It can vaporize or fracture the material. In general, laser engraving involves cutting through paint.

For a laser-engraved piece of glass or plastic, a standard cast acrylic plastic sheet is perfect. However, some thermoforming plastics and styrene tend to melt around the engraving spot, resulting in uneven or distorted edges. A softened plastic surface will also lack contrast and may ripple, especially in the lip area. However, some materials lend themselves to laser engraving. One example is a date-marking on a two-litre soda bottle.

Fiber lasers

Fiber lasers are used for cutting, laser engraving, and marking a wide range of materials. Fiber lasers are ideal for marking metals such as gold, silver, and platinum. Lasers of this type create highly reflective and textured marks. As the laser wavelength is not controlled, wood is subject to absorption. Thus, the finished product is irregular and barely recognizable. But, fiber lasers do not require a specialized cooling system.

A fiber laser is also suitable for marking transparent materials like glass, plastic, or PET film. The fiber laser can pass through the transparent material and reflects back from the bottom. Some polymers can be temporarily colored by a fiber laser, which can be removed with cleaning agents. As with any laser, eye protection is essential. Fiber lasers are capable of making different kinds of marks, such as lines, symbols, and text.

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