Metal marking – applications for etching, polishing and annealing

TODAY nearly every industry has a need for permanent metal marking. Whether it’s marking tools with serial numbers, medical devices with logos or even producing architectural signage that calls for a sleek look on metal surfaces, businesses are in need of metal marking solutions.

Adrian Holdaway of Project Engraving & Digital told Manufacturers Monthly, “The FiberMark system is the latest in Epilog Laser’s product line, not only meets this need of our customers, but exceeds it by producing a versatile machine that is extremely user-friendly and convenient to operate”.

The FiberMark goes beyond the boundaries of traditional metal marking lasers, as it incorporates a large 605mm (24-inch) by 300mm (12-inch) marking area, state-of-the-art fiber laser technology with flying optics beam delivery to create a system that is economical, easy to use, and advantageous over traditional Nd: YAG galvo based beam delivery systems. The FiberMark is also unique in that it is the only system of its kind to operate directly from almost any Windows-based software such as Word, CorelDRAW, AutoCAD, and other popular software packages.

The fiber laser is a relatively new class of laser used for marking applications. Essentially it is a fiber optic cable that has been doped with Ytterbium. By pumping the fiber optic cable with light to excite the Ytterbium, the optic cable is able to act both as the laser source and as the delivery system for the laser beam. A fiber laser emits a wavelength between 1055 to 1070 nanometers in the infrared range similar to YAG lasers. Until recently, the fiber laser was only available in a continuous wave mode, not pulsed. This significantly hindered the machine’s applications. The high per-pulse energy of the FiberMark and the much smaller wavelength is what makes marking on metal feasible.

Etching is often used for industrial purposes — marking tools or parts with serial numbers, logos and bar codes. The etching process of the FiberMark actually removes small amounts of material from the sample.

Polished metal, or ‘mirrored’ as it sometimes called, is a laser effect where the laser beam heats the surface of a material and as it cools, the material takes on a different finish than the surround material. Most common on matte-finish metal, this technique creates marks that can look almost holographic.

The annealing process is similar to the polishing process. The laser is used to heat metal to near melting points, which induces a colour change to the top layer of material.

Annealing often gives a dark iridescent look, with a faint rainbow of greens, blues and pinks that can sometimes be seen in the text or graphic. Since no material is removed from the metal, this technique is often used for medical devices used within the human body.

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