While laser engraving has a wide spectrum of uses, the more sophisticated of these is most evident in its use with specialized materials, such as polymers and alloys. Laser marking designates a range of marking, such as printing, branding, and bonding. The terms “laser engraving” and “laser marking” are often used interchangeably, because the equipment they use consists of the same components: laser, controller, and surface. By movement of the laser beam, much as you would a pencil, the controller directs and controls the direction, intensity, speed and swath of the laser’s beam as it’s applied to a surface.
Laser engraving technology has been widely adopted on production lines. It is particularly useful for high-detail relief work, such as expiration and printing dates, and lot or serial numbers. Depending on the detail and precision involved, either a laser table (or “X-Y table”) or flat table will be used to stabilize and focus the laser beam. Focusing systems, such as dynamic auto focus, can adjust laser parameters while an area is being engraved or marked. Vector engraving affords a greater degree of flexibility, e.g., fill areas, font rotation, and dynamic scaling, than earlier versions of laser printing.
Raster engraving – a process in which a laser is traced across a surface, back and forth, has the advantage of virtually effortless “fill”. When an image has large or engraved areas or bold letters, it is usually well-rasterized. Even photos can be rasterized.
Some of the materials that can be engraved include the following:
- Wood – which is burned (literally) with images (walnut, mahogany and maple, are very suitable)
- Hard papers and fiberboard
- Some latex rubber compounds
- Plastics - acrylic plastic, acrylic plastic sheet, Bakelite, and other cast resins, all work well (additionally, silicate or other mater infused plastics are also suitable)
- Metals
- Stone and glass (specifically sandblasting or cutting with diamonds, work better with these materials)
- Jewelry
- Fine Art
Source: http://en.wikipedia.org/wiki/Laser_engraving
http://www.coherent.com/Applications/index.cfm?fuseaction=Forms.page&PageID=250
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Mark Williams is the author of this blog post about laser marking. He is an engineer and science geek who loves laser technology. Feel free to connect with him over at Google+.