Laser etch machines

A laser etch machine can be thought of as three main parts: a laser, a controller, and a surface. The laser is like a pencil - the beam emitted from it allows the controller to trace patterns onto the surface.
There are three main genres of etch machines: The most common is the X-Y table where, usually, the workpiece (surface) is stationary and the laser optics move around in X and Y directions, directing the laser beam to draw vectors. Sometimes the laser is stationary and the workpiece moves. Sometimes the workpiece moves in the Y axis and the laser in the X axis.
The point where the laser (the terms "laser" and "laser beam" may be used interchangeably) touches the surface should be on the focal plane of the laser's optical system, and is usually synonymous with its focal point. This point is typically small, perhaps less than a fraction of a millimeter (depending on the optical wavelength). Only the area inside this focal point is significantly affected when the laser beam passes over the surface.
A laser can remove material very efficiently because the laser beam can be designed to deliver energy to the surface in a manner which converts a high percentage of the light energy into heat. The beam is highly focused and collimated - in most non-reflective materials like wood, plastics and enamel surfaces, the conversion of light energy to heat is more than {x%} efficient {example reference needed}. However, because of this efficiency, the equipment used in laser etch may heat up rather quickly. Elaborate cooling systems are required for the laser.
Raster etch traces the laser across the surface in a back-and-forth slowly-advancing linear pattern that will remind one of the printhead on an inkjet or similar printer. The pattern is usually optimized by the controller/computer so that areas to either side of the pattern which aren't to be etchd are ignored and the trace across the material is thus shortened for better efficiency. While traditional sign and plaque etch tended to favor the solid strokes of vectors out of necessity, modern shops tend to run their laser etchrs mostly in raster mode, reserving vector for a traditional outline "look" or for speedily marking out lines or "hatches" where a plate is to be cut.