Laser scanning
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Laser scanning describes a method where a surface is sampled or scanned using laser technology. Different areas of application exist, these mainly differ in the power of the lasers that are used and in the results of the scanning process. Lasers with low power are used when the scanned surface does not need to be influenced, e.g. when it must be digitized. Confocal or 3D laser scanning are methods to get information about the scanned surface.
[edit] Material processing and production
Depending on the power of the laser, its influence on a working piece differs: lower power values are used for laser engraving, where material is partially removed by the laser. With higher powers the material becomes fluid and laser welding can be realized, or if the power is high enough to remove the material completely, then laser cutting can be performed.
Also for rapid prototyping a laser scanning procedure is used when for example a prototype is generated by laser sintering.
The principle that is used for all these applications is the same: software that runs on a PC or an embedded system and that controls the complete process is connected with a scanner card. That card converts the received vector data to movement information which is sent to the scan-head. This scan-head consists of two mirrors that are able to deflect the laser beam in one level (X- and Y-coordinate). The third dimension is - if necessary - realized by a specific optic that is able to move the laser's focal point in the depth-direction (Z-axis).
The third dimension is needed for some special applications like the rapid prototyping where an object is built up layer by layer or for in-glass-marking where the laser has to influence the material at specific positions within it. For these cases it is important that the laser has as small a focal point as possible.
For enhanced laser scanning applications and/or high material throughput during production, scanning systems with more than one scan-head are used. Here the software has to control what is done exactly within such a multihead application: it is possible that all available heads have to mark the same to finish processing faster or that the heads mark one single job in parallel where every scan-head performs a part of the job in case of large working areas.
