Laser Engraving – An introduction

Lasers have come a long way. In 1960, Theodore H. Maiman was the first to successfully operate a device called a Light Amplification by Stimulated Emission of Radiation or LASER. Today, we use lasers in CD/DVD/Blu-Ray players, as pointing devices for presentations, for surgery, and a variety of other uses, including etching, cutting, and marking.

Laser engraving and marking has many applications. Some of the uses include marking surgical pins and equipment, preparing burial headstones for sandblasting, and marking decorative or personal items. Equipment can be as small as a desktop printer up to the size of a cars or larger. For small businesses, a tabletop version is the right combination of space, power, cost, and flexibility of materials that can be etched, marked, or cut.

Depending on the need and material, different type lasers are required or function better than others. Many of the tabletop machines utilize CO2 lasers with power ranges around 30 watts up to 120 watts. Machines in this power range will cut, mark, and engrave a variety of materials including acrylic, wood, plastics (no PVC due to the vapors created during the etching that will damage the machine), Corian, marble, granite, brick, clay, paper, and many other materials. Most materials can be cut and engraved in two different ways, raster and vector.

Most laser etchers will operate in two modes, raster and vector. A raster image, or bitmap, is a graphic structure where every point in the image is defined. Take for instance a photograph; no matter where you look on a photograph, there is a color, even if that color is pure white or pure black. In digital terms, a Jpeg image is a raster image that has been compressed for a smaller file size. When you enlarge a Jpeg image, depending on the encoding quality, you may see some discolorations around hard edges such as the edge of a building against a clear sky. The resulting file is very small compared to the raw data, but there is some quality issues associated with the size savings. Raster images are very important but are limited to what they can do and how they can be manipulated. Vector images, on the other hand, have some important benefits and limitations as well.

Vector graphics, in a very basic form, utilize information to generate or draw the line as opposed to data for every point. For example, a vector line will have a starting point, a line length, and a direction. It can be scaled up and down because there are no line thicknesses. With raster images, the quality of the image depends on the resolution at which it was taken. The benefit of vector graphics is the ability to resize without losing any quality and because of that benefit, many logos and graphics are vector graphics. Vector graphics are typically created in programs such as CorelDraw, Adobe Illustrator, Inkscape, and AutoCAD.

Laser etchers, depending on the design file, can etch and mark in either raster mode or vector mode. In raster mode, the laser varies the strength of the laser to etch and mark the material with the shading in the design. When etching granite or marble with a photograph, raster mode is used. In vector mode, the speed and power stays constant and the laser turns on and off as dictated by the design. If Christmas ornaments are being cut from wood, vector mode is typically used. In any design, there can be a mixture of raster and vector operations. For example, if someone wanted a picture frame with their child’s face etched in the corner and a custom sized cutout for the picture, raster mode would be used to etch the face and vector mode will be used for the custom cutout.

Lasers have found a useful place in our lives. They link us with our surgical implants, they help us do our jobs and presentations better, and they enhance our lives through decorative items. What can you think of that would be better off personalized with a laser etcher?