There is currently a buzz surrounding the commercial laser-use industry. Better machines, lower prices, smaller sizes with large power outputs and high efficiency have made customers stop and look at the industry and genuinely consider how they can apply it to their own businesses. But, there seems to be a bit of confusion when it comes to terminology and uses. The terms etching, engraving and marking are being bandied around to the overall detriment of customer understanding.
Engraving is probably the most recognized form of laser work in peoples minds. Like the traditional craft of old, laser engraving seeks to remove physical layers of the material to create a cavity which will inevitably form an image. In the olden days an engraver would physically remove layers of the material using an assortment of specialized tools. With lasers the process is done quickly, much more quickly. The extreme heat generated by the laser burns or vaporizes the material in almost the blink of an eye. Deeper cavities can be produced not by applying more power or wattage to the laser but by passing over the area to remove layers.
The depth of the engraving can be adjusted depending on the density of the material being used. Harder and denser materials like metal can withstand an engraving of 0.020” deep. However, lighter and less dense materials like graphite can only withstand 0.125” deep, as deeper engraving may compromise the structural integrity of the material. This makes engraving a very versatile method of creating a mark on a piece of material, which is why this is the preferred method for personalization and customization. No special parts, method, know-how or materials are required, just a different engraving depth is required.
You can think of etching as a specialized form of engraving. Where engraving marks the material by vaporizing or burning off layers of the material, etching merely melts it instead. The overall mass of the material has not changed rather the immense heat generated the laser distorted the surface of the material. The end result is a less refined product than an engraving, however it does produce a finish in which, more often than not, the area of etching is raised from surface of the material providing a distinct and noticeable contrast. Understandably the laser does not penetrate deeply when etching, only about 0.001” from the surface.
Finally, there is marking. Think of this as the umbrella upon which all other types of laser work falls under. Generally speaking, laser marking is the process in which a laser is used to alter properties and appearance of the surface of a material using focused heat. So engraving is a specialized form of marking and that would make etching, a highly specialized form of marking.
On a high level, marking uses low-powered lasers to create a pattern of discoloration in the material. This is done by causing oxidation beneath the surface of the material and turning the pattern into a dark shade. Think of this as controlled rust that keeps the surface of the material intact and unblemished, unlike engraving and etching which forever changes the surface with their methods.
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Article written by Erryn Deane from Needham Coding
Erryn is the digital business manager for The Needham Group of companies, with a wealth of knowledge in laser marking systems, amongst many other things, he has decades of experience in online development, business analysis and management. In his spare time, he likes to find out how things work and looks to improve them, from vehicles to electronics or even musical instruments.