Understanding lasers (I)
Like many discoveries of recent times, lasers were first conceived in a laboratory. It was in the early 1960s when scientists first discovered, that they could create a light source, focus the energy and have a tool powerful enough to affect certain materials. They named these first light sources LASER, an acronym for Light Amplification by Stimulated Emission of Radiation.
Think of a laser as a light source similar to a light bulb. A light bulb will emit energy out all around it. A laser puts energy out of a tube, usually 1/2" diameter. The energy is collected from a larger area and focused onto a fine spot size, where the energy is the most dense. The concept is similar to using a magnifying glass in the sun. Move the magnifying glass up and down and you lose concentration of the energy. And, just like the sun through a magnifying glass can be powerful enough to burn through paper, a leaf, or other material, so can a laser.
It didnt take long for industry to notice lasers and soon lasers were being used for a wide variety of industrial applications including welding, heat-treating, etching and engraving. Early laser physicists experimented with several types of methods to generate the light source, thus creating several types of lasers. For the engraving industry, CO2 lasers, named for the gasses used to create the light source, are the tools of choice.
Similarly to light bulbs, lasers are rated by wattage. Simply put, the higher the wattage, the more powerful the tool. Engraving lasers generally range in power from 10 - 100 watts.
Engraving with a laser is actually a fairly simple process. The laser emits the beam of light. The beam goes though a corner bock and is turned by a mirror and out to a focusing assembly which focuses the beam down to the material, where it actually vaporizes the material.
There are a variety of advantages to using a laser over other methods of engraving. First of all, because the tool is a beam of light, there is no product contact, which translates into less chance of product damage or deformation. Tooling does not wear out, or need to be replaced as in other methods of engraving. Additionally, a laser will provide more versatility in material and product choices. Laser can engrave most materials. The most popular in the engraving fields are coated metals, wood, acrylic, glass, leather, marble, plastic, and host of synthetic materials made specifically for lasers. Additionally, the same machine that engraves can also cut through thin materials, providing even more versatility for an engraver. Lasers are also faster engraving up to 80/second. (depending on machine, material choice, artwork and desired effect) There are no consumables so operating costs are minimal, and the laser system, if properly exhausted, runs clean, so that costly cleanup or by product disposal is unnecessary.
Today's laser engraving equipment is safe, easy to learn, run and maintain. The systems are meant to run similarly to a laser jet printer. With the machine, you get a driver, which is installed onto your pc much like a new printer would be added to your system. The laser system is connected to a pc via a parallel port printer cable. Artwork is generated via a graphics program (i.e.. CorelDraw) and sent to the engraver much like a word document is sent to a printer. Most engravers find that the biggest challenge in learning to run of these systems is in mastering the graphics software. The operator can control settings for power, speed, and resolution.
By combining the latest laser technology with the latest in computer technology, manufacturers have truly created a unique versatile tool that will continue to make its mark on the engraving industry for years to come.
By Diane C. Bosworth