A laser engraving machine has three main parts: a laser, a controller, and a surface. The laser is like a pencil - the beam from it allows the controller to trace patterns onto the surface. The controller (usually a computer) controls the direction, intensity, speed of movement, and spread of the laser beam aimed at the surface. The surface changes depending on the material being engraved.
Laser printing is done in raster which is for pictures and vector which is for cutting lines.
There are three main kinds of engraving machines: The most common is the X-Y table where the surface is stationary and the laser moves around in X and Y directions. Sometimes the laser is stationary and the workpiece moves. Sometimes the workpiece moves in the Y axis and the laser in the X axis. A second kind is for cylindrical workpieces where the laser effectively around the cylinder and on/off laser pulsing produces the desired image. In the third method, both the laser and workpiece are stationary and mirrors move the laser beam over the workpiece surface.
If the surface material burns during laser engraving, ventilation through the use of blowers or a vacuum pump is required to remove the noxious fumes and smoke and to remove debris on the surface to allow the laser to continue engraving.
A laser can remove material very efficiently because the laser beam can deliver energy to the surface with a high percentage of the light energy changed into heat. However, because of this efficiency, the equipment used in laser engraving may heat up quickly. Cooling systems are required for the laser or the laser beam may be pulsed to lower heat.
Natural materials
Directly burning images on wood were some of the first uses of engraving lasers. The laser power required here is often less than 10 watts depending on the laser being used as most are different. Hardwoods like walnut, mahogany and maple produce good results. Softwoods can be engraved but tend to vaporize at less-consistent depths. Burning a softwood with a fan blowing on it requires lowest power, quickest speed of cut, and enough airflow to extinguish what is trying meanwhile to ignite. Hard papers and fiberboard work well; linty papers and newsprint are like softwoods. Fur is not engraveable; finished leathers though can be laser-engraved with a look very similar to hot-branding.
Plastics
Standard cast acrylic plastic, acrylic plastic sheet, and other cast resins generally laser very well. Styrene (as in compact disc cases) and many of the thermoforming plastics will tend to melt around the edge of the engraving spot. The result is usually "soft" and has no contrast. The surface may actually deform or "ripple".
For signs and face plates, etc., special plastics were developed. These incorporate silicate or other materials which conduct excess heat away from the material before it can deform.
Other plastics may be successfully engraved. Bakelite is said to be easily laser-engraved; some hard engineering plastics work well. Plastics with a chlorine content (such as vinyl, PVC) produce corrosive chlorine gas when lasered, which combines with Hydrogen in the air to produce vaporized hydrochloric acid which can damage a laser engraving system.
Many light switchplates from companies such as Leviton or Lutron can be laser engraved. Carefully experiment to develop the correct laser settings to engrave the surface rather than melting it.
Kevlar can be laser-engraved and laser-cut. However, Kevlar does give off extremely hazardous fumes (cyanide gas) when it is vaporized.
Metals
Using special laser machines, metals can now easily be engraved using commercial systems.
Stone and glass
Stone and glass do not turn to gas very easily. As expected, this makes them generally a better candidate for other means of engraving, like sandblasting or cutting using diamonds and water. But when a laser hits glass or stone, something else interesting happens: it fractures. Pores in the surface expose natural grains and crystalline "stubs" which, when heated very quickly, can separate a microscopic sized "chip" from the surface because the hot piece is expanding relative to its surroundings. So lasers are indeed used to engrave on glass, and if the power, speed and focus are just right, excellent results can be achieved.[7] One should avoid large "fill" areas in glass engraving because the results across an expanse tend to be uneven; the glass ablation simply cannot be depended on for visual consistency, which may be a disadvantage or an advantage depending on the circumstances and the desired effect.