Laser Engraving: Seeing the Light

May 4, 2004

   High-tech machines and some off-the-shelf software allow for more creativity than traditional sandblasting … and directing customers to the best stones for these applications can also help put extra money in your pocket.

MIXED MARKETS
   The ability to marking stone is literally as old as civilization itself, but a laser engraver just puts a high-tech spin on the process.
   Brad Moore, president of Calgary, Alberta-based CAM Tech Industries Inc., says the laser-engraving process actually borrows a bit from an ancient Chinese practice where skilled artisans created photographic-type images by physically hitting the stone with a diamond tip.
   “What a laser does is simply explode the stone the same way hitting it with a diamond tip does,” he explains. “The hole explodes the stone, leaving what is a single dot in a gray-scale photograph.”
   “You’re really just microchipping the surface,” says Jim Rabideau, market development manager for Scottsdale, Ariz.-based Universal Laser Systems. “If it’s black marble, it turns white, so it’s really going to stand out.”
   When Rabideau uses the word “microchipping,” he isn’t kidding. Although some photo masks created for sandblasting can handle resolutions of up to 72 dots-per-inch (dpi) – depending on the substrate – Dirk Burrowes, president of Fitchburg, Mass.-based Vytek, says laser’s ability to create at 300 dpi is only part of its advantage.
   “Not only is that 300 dpi at least four times higher the resolution than what you would get from a sandblasting mask, you don’t have to make a mask and – because of the software – you have total edit capabilities,” Burrowes says. “You get more detail, and you’re going to be able to be more creative as a result of that, whether it’s putting five-point text in marble or blowing something up to be extremely large.”
   The size of the finished product is certainly one issue fabricators should plan to keep in mind when shopping for a laser engraver. Many monument shops are already utilizing machines with larger capabilities, such as those from CAM Tech and Vytek. There are certainly others out there, although many of them are aimed primarily at different markets, such as the engraving market.
   “The key thing fabricators need to know is who is their target market,” says Burrowes. “Are they principally doing residential work, or do they mainly do commercial applications? That helps focus the shopping decision, because there are small machines for smaller applications, as well as large machines for larger applications.”
   On the less-expensive end of the scale, many manufacturers with smaller machines aimed at the engraving industry have with tables that only support 40-60 lbs., which is fine for stone tiles and a problem for slabs. For example, Universal’s largest machine has a table that’s 28” X 18” and is available for approximately $12,000.
   Several manufacturers offer machines capable of supporting a substrate of 150-250 lbs., including Jackson, Mich.-based Trotec Laser Inc.; Baton Rouge, La.-based Xenetech Global; Golden, Colo.-based Epilog Laser; and Walnut Grove, Calif.-based GCC America.
   However, problems can arise with some models because their top-loading feature makes it difficult to move stone in and out.
   “Our Professional model has doors in both the front and back, which gives you some flexibility in mounting the materials,” says Trotec’s Geoff Thompson. “Certainly if you’ve got big stones going in and out it can be an issue. But, with our 51” X 51” work area, you can do a lot of things at one time.”
   With their equipment designed specifically for the stone industry, companies such as CAM Tech and Vytek have eliminated the handling issues present with smaller machines.
   For instance, Vytek’s M-Series is open-framed and designed with roller tracks so large slabs or even contour cuts can be rolled in and engraved.
   “We have a line developed only for monuments with a self-loading cart and pneumatic pull-in system,” says CAM Tech’s Moore. “Our other systems are multi-functional. You can fill the entire surface with 3/4” tile or you can pull the tabletop out and cart stones in underneath.”

TEST OF SKILL
   While finding the right size machine for the job is half the battle, the other is in getting one with enough power to properly do the job.
   Early laser engravers came with as little as 10 watts of power; today’s wattages are considerably higher. However, rather than assuming that bigger is better, it’s more a matter of getting the power that’s right for the job.
   “You can get the job done with a 30-watt laser, but if you want to achieve some depth, the higher wattage is going to give you that,” says Jimmy du Bose, director of sales for Xenetech. “On a 30-watt machine you’re just going to be going slower to get the same depth that you could get with a 100-watt machine.”
   “A 30-watt machine would be my minimum,” says Kurt Koser, a distributor for GCC America through his Morgan Hill, Calif.-based LaserPro. “But, 120 watts isn’t too much when working with black marble. Power is contrast on black marble. The more power the material absorbs the higher the contrast, or whiter the engraving.
   “A more powerful laser will not do a better job; it will just produce higher contrast faster. Granite works great at low power but gives courser results as the dot produced it far bigger and less round.”
   And, different laser technologies can affect how much power is needed for stone. Components from Synrad Inc. in Mulkiteo, Wash. (and used, for example, in CAM Tech models) can effectively mark marble and granite with as low as an 18-watt laser.
   Vytek’s Burrowes says it’s often a matter of hitting a happy medium with the machine’s power. For example, some softer materials, such as travertine and some of the sedimentary stones, can be engraved more deeply, but the process requires greater power.
   “However, at some point, laser power becomes detrimental because of the nature of the materials being engraved,” he says. “You’re engraving with a wavelength of radiation and the material can only absorb so much radiation. You can use a higher power, but you obliterate the stone.”
   Burrowes adds that the vast majority of his company’s stone customers go with a 30- to 35-watt machine, with only about 10 percent going for those with higher power levels.
   Koser says some of that is due, too, to the fact that stone is much less forgiving than other materials that may be laser-engraved.
   “If you’re engraving aluminum or brass or wood, if anything varies a bit you aren’t going to see it in the end product and the variance is going to be virtually invisible,” he says. “But, if the tube fluctuates, if the machine has some vibration or the driver doesn’t quite control the power properly, you’ll see it with black marble.”
   Since there is no penetration, all the laser does is change the contrast. If the laser is not working properly, any variance shows up as contrast changes.
   It’s a problem that can show up easily with photographic images. In those cases, one option is to go with a less-detailed file, says Koser.
   “What you want is fewer dots,” he says. “Even then, you run the risk that you end up making a rectangle instead of a photographic image.”
   That’s why it’s a must to have different manufacturers produce the same images for you when you’re shopping for a system using comparable wattages and sizes, says Epilog’s James Stanaway.
   “Compare image quality, total time from start to finish, depth of burn and ease of use,” he says. “Always request to see the laser system in action under a number of different circumstances. You always want to see the system operate with your own eyes.”
   While it sounds complicated, one of the nicer things about these machines is that they run with off-the-shelf software that many people are already familiar with through other applications.
   CAM Tech’s Moore says his clients generally utilize Corel Corp.’s Corel Photo-Paint® or some of the more popular photo-editing software packages.
   “Of course, there’s some skill involved,” he says. “It would be an illusion to say that if you’d never worked with a computer or edited a photo that this information is instantly going to be in your brain, but at its most-skilled level, it’s just another trade; only your tool is different.”
   Additionally, Koser notes that Photo-Paint and its companion vector-line graphics software, CorelDRAW®, will has the features that will allow even a shop using a small machine to build a mosaic of up to 150’ X 150’ by engraving on individual tiles.
   Even though many of the programs used to run these machines are familiar to large numbers of computer users, the equipment manufacturers also offer additional training on them.
   For instance, while Burrowes says Vytek’s machines operate with all the standard formats of image files, the company also offers on-going classes at its Massachusetts headquarters, and offers CD and DVD training programs that take the user through the whole process of image creating, scanning, editing, and creating murals and designs.

THE RIGHT STUFF
   Having the right machine, a good design and good software to help execute it are only pieces of the laser-engraving puzzle. Final success will also depend on good material, because not all stones respond equally well to laser engraving.
   As a natural product, stone certainly isn’t without its flaws and inconsistencies. Having a vein appearing at the tip of someone’s nose in a photo image is only one potential problem.
   “If you have black marble with a vein running through it that’s gold or another color, it might be fine,” says Xenetech’s du Bose. “However, if a letter is going across that, you’re going to see a variation in the letter itself because of the different density of the stone and the different composition in that one area.”
   Universal’s Rabideau refers to that background problem as “noise,” and says one way to check for potential problems ahead of time is to print a transparency of the design and see how it’s going to sit on the stone
   In a perfect world, black marble would probably be the stone laser-engraved most often because of its softness and its ability to produce good contrast. However, it’s unlikely it’s the stone choice of every customer, and it’s not the only option.
   The trick, says CAM Tech’s Moore, is to find a stone with a fairly monotone appearance if you’re planning to do photographic engraving.
   “If there’s a heavy pattern to the background, a detailed etching can be irritating,” he says. “Black granite, dark greens and dark reds are all good. You want something where the pattern of the stone isn’t central.”
   For non-photographic types of work such as text and line art, Burrowes says just about any stone can be laser-engraved, including slate and soapstone.
   “If the customer wants vines going down a stone backsplash or the family crest over a fireplace, most stones can handle it,” he says. “Photographs are high-resolution and so you want a fine-grained stone, a low calcium-based stone. Stone with lots of quartzite between the grains is very poor for pictorial art.”
   Because it’s both an image-driven and a material-driven process, Burrowes says part of Vytek’s training process is helping new laser engravers learn to identify which stones can and cannot be engraved, and also how to test engrave to determine how detailed an image will work on a particular stone.
   Certainly one way to make the process easier is to always work on good-quality stone. And Burrowes says once a fabricator can get a customer interested in laser engraving, it often stimulates that buyer to move up to a higher-quality material.
   “They become focused on the laser engraving, and the fabricator can help them choose the materials that will identify their laser engraving the best,” he says. “A fabricator should be able to sell better stone at a better price and still leave the customer more satisfied.”
   Burrowes says that’s true even when the laser engraving is only a small part of the job, because it extends into the materials for the rest of the project. And, it also sets the seller apart from other fabricators and installers in the market.”
   As with any product or service, a lot of success depends on how it’s marketed, and being able to create unique looks has to be a drawing point for customers.
   Trotec’s Thompson says stone fabricators also need to be aware that having a laser engraver can expand the scope of work they’re doing.
   “We see people doing tiles for walls and floors for fundraising events by libraries, churches and other charities,” Thompson says. “Donor acknowledgements in tile or brick or stone are very popular right now, and it’s not much different than doing tiles for a residence or business. It can be used for all different kinds of applications.”
   In the end, however, success or failure often depends on simply letting customers know laser engraving is available and what it can do.
   “The marketplace is still so new it does require some commitment on the fabricator’s part to help educate customers about what they can get,” says Burrowes. “It may mean making some changes to the showroom or even producing some small samples for customers. You need to tell them it’s new and exciting.”