Laser Etching

Laser etching, also known as laser engraving, is the process of using concentrated, amplified beams of light to mark one or more objects. The laser is often controlled by a computer system as the process often is complicated. The combination of computers and lasers can produce extraordinarily complex but precise engravings on a wide range of materials.

Types

There are many different types of etching machines, and several different ways in which the laser is delivered to the desired point on the etching material. The most common is the X-Y table, where the beam moves around the surface of a stationary workspace. There also are machines that have a fixed laser and move the workspace around the laser, and machines that assign one axis to the laser and the other to the workspace. There also are laser etching machines where the workspace is cylindrical in shape, and complex machines that have both a fixed laser and workspace and rely on movable mirrors to direct the path of the beam.

Effects

When a laser passes over the surface of the material, only the material directly under the beam is affected by the energy transfer of the beam. The laser is designed to deliver enough energy to vastly and quickly heat the surface of the material under it, enough to either vaporize a thin layer of the material or else fracture or flake the surface of the material. Subsequently a small amount of material is removed from whatever object is being engraved, resulting in some form of marking.

The lasers of etching machines are designed to deliver a type of energy to the surface of the engraving object that converts a very high percentage of light into heat, resulting in a powerful effect at a very precise point. Because of this, engraving machines tend to heat up very fast and require large cooling systems, in addition to blowers or a vacuum system to remove any fumes created during the vaporization process.

Function

A wide variety of materials can be engraved with the use of a laser etching machine, including natural materials like wood (hardwoods such as oak, mahogany, walnut and maple produce the best results), hard papers, fiberboard, leather and certain rubber compounds. A similarly wide variety of plastics can be engraved as well, including acrylics, styrene, leviton, lutron, bakelite and those filled with an insulating material such as urethane and silicone. Almost all metals are easily engraved using machines that use Nd:YVO4 or Nd:YAG lasers at 1,064nm wavelength. Stone and glass do not vaporize easily, but are susceptible to a "chipping" effect which removes microscopic chips from the surface of the material.

Considerations

There is high demand for laser etching in many fields of commercial production. Personalized jewelry is very popular, and jewelers have found that the quickest and most precise way to accomplish the task of personalizing jewelry is with laser etching. Recently laser etching also is being used to create fine art. The artist will convert a drawing or image to a digital form readable by the machine's computer. This method creates grooves that are often filled with glass, ink or another material. Laser etching also is used for a number of industrial applications, including printing and direct laser imaging.

Expert Insight

The point at which the laser touches the material is on the focal point of the laser's optical focus. On nearly all machines this focal point is less than 1 millimeter in diameter.

Vector engraving is done with either PostScript (a type of computer language) or PostScript-enabled software such as CorelDRAW or Adobe Illustrator. This is to help with setting up the sequence of laser cuts that will actually produce the desired result on the engraving material.