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Information Sheets
Laser Engraving/Scribing
Laser engraving, or deep marking, is an application typically based on the process of laser induced ablation, either by vaporisation or melting displacement. To achieve this result the intensity of the laser beam incident on the target has to exceed a threshold value specific to that material. This intensity value maybe particularly high on electrically conductive metals such as metals. Also, the absorption of the laser energy at any specific wavelength varies across different materials, and therefore several laser types are often considered. However, CO2 (10.6µm) and Nd:YAG (1064nm) lasers dominate in most commercial systems on the market. These lasers have the benefits of being a mature, reliable technology, cost effective and easy to use. For the highest speeds systems based on galvanometer scan heads are often preferred, but these usually have a limited engraving area. Large area engraving systems on the other hand typically adopt a flying optics configuration to provide engraving areas of 1 metre square, or bigger.
Laser engraving has many advantages over conventional engraving techniques:
1). It’s non-contact. The laser beam has no mass, and no force is applied to the part during processing. Therefore even extremely delicate parts can be engraved without deforming them, and neither is any clamping or jigging required to hold the part. Also being non-contact, there is no mechanical tooling to wear out or require maintenance.
2). High speed. Compared to router or mechanical saw systems, the laser can deliver the highest engraving speeds and productivity.
3). High quality. Laser engraving produces a crisp, highly detailed mark, with small feature sizes that are unobtainable with other technologies. Laser engravers offering resolutions of 1200 DPI are available.
4). Ease-of-use. Most systems are based on simple graphical user interfaces that allow the operator to import a wide range of different image formats including both bitmaps and vector artwork. These are easily positioned in the engraving area, and within just a few simple mouse clicks the job can be running.
Many materials can be laser engraved, the following list is many but by no means exhaustive….wood, fabrics, plastics, cork, delrin, glass, leather, acrylic, foams, stone, polyester, veneers, ceramics, stainless steel….
The width and depth of the laser engraved line depends on the size of the laser spot focused on the target, the laser beam profile and certain properties of the material such as its thermal conductivity. The result is often a cone shaped indentation or groove. To achieve a wider and deeper engrave multiple passes of the laser beam around the same path are sometimes used. Laser scribing applications on the other hand typically require the scribed line to be only as wide as a single laser beam and to achieve a specific depth tolerance. The scribed line consists of a series of small closely spaced holes produced by high energy laser pulses. Viewed under magnification, the scribe holes should appear essentially clean and free of recast. Glasses and ceramics are materials commonly laser scribed, usually to provide a ‘break line’ for separating individual components from a larger sheet. Other laser scribing applications provide ‘easy tear’ regions to plastic food packaging. On multi layer products it’s possible to cut individual layers leaving others untouched.