Laser engraving systems come in a wide variety of configurations to accommodate jobs both small and large. Slabs as large as 4 feet by 8 feet and larger can be successfully handled without difficulty. Large-format lasers usually come either with a stationary table and a gantry-mounted laser, or with movable table. Some systems also use conveyor belts. Prices for large-format laser engraving systems are about $70,000 for an average system.

If you're interested in cutting completely through a piece of stone, your best bet is the CNC abrasive waterjet. Although there are several other tools on the market today that will do precision stone-cutting, for highly detailed artwork the waterjet offers some significant advantages: It doesn't heat the material being cut, it doesn't vibrate the material, and it doesn't require a starting hole. For Jim Bellilove of Creative Edge, it was love at first sight when he saw a waterjet. "We got involved with the waterjet first, and then we found a market," he says. "Our basic business concept is organized around the machine."

Creative Edge is actually two businesses in one. Bellilove operates both in the artistic realm, serving the needs of the architectural-design market, and in the industrial realm, using his machines to do industrial cutting. He has expertise in executing complex inlays that combine a variety of materials, such as stone, tile, and metals. "This kind of equipment is the best breakthrough in stone-cutting in hundreds of years," Bellilove says. "Any shape can be cut as long as the material is flat. Any material can be combined with stone. The technology just by itself creates a whole range of design possibilities." The waterjet works by shooting out a fine stream of water at high speed. However, when you're cutting through stone, water alone is not enough. You'll also need an abrasive. The most common one used with the waterjet is garnet.

Surprisingly little water is used by the waterjet itself . It only uses about a gallon a minute that is sprayed out of its tiny nozzle in a stream going about3,000 feet per minute, with about 50,000 PSI of pressure behind it. The waterjet stream used to cut stone is generally in the range of 0.003 inch. Since the kerf is extremely small and the material surrounding the cut doesn't heat up and warp, there is very little wasted material in a waterjet operation. In addition, the waterjet doesn't need a pilot hole to get started on an interior cut. It pierces right through the material wherever it begins, without leaving perceptible evidence of where the cut started. In order to use the waterjet and your computer together, you will, of course, need to use a CNC motion system. This handy little bit of hardware interprets the computer's digital instructions during the printing process and makes the waterjet act like a stencil-cutting machine.

The advantages of using a CNC abrasive waterjet for precision stone cutting are many. It can cut the time necessary to produce complex stone cutting from weeks to hours. Because the waterjet doesn't heat up the stone or vibrate it, the resulting cut pieces are free of cracks and cut to a precision of +/- 0.005 inch. A waterjet is best used to make cuts completely through the material on which it is working-and it can cut through stone up to 8 inches thick.

However, some operators are using the waterjet for specialized engraving. Brandon Gates, production manager for Precision H2O of Spokane, Washington, says he regularly uses the waterjet to etch complex designs on stone. "We've etched with no problem and gotten some beautiful results," says Gates. To cut a groove in stone, instead of going completely through, Gates increases the head speed, decreases the water pressure, and decreases the garnet flow. Because the bottoms of the grooves aren't a consistent depth, Gates fills them in with grout, leaving behind an attractive precision etching in a contrasting color.

Waterjet systems come in a variety of configurations. Typically prices begin at about $100,000 for a basic CNC system. Although the waterjet only uses about a gallon per minute for the actual cutting, it uses another 5 to 7 gallons per minute to cool the pressure intensifier pump. While water consumption is not excessive, and there are no blades or bits to wear out, there is still a fair amount of maintenance that must be regularly performed. Says Bellilove, "There are a whole bunch of components in the system, which, because of the high water pressures, wear out quickly." High pressure takes its toll on the waterjet's hoses and gaskets. The garnet abrasive, an expensive supply in and of itself, causes the waterjet nozzles to wear out quickly, as well.

Yet, in spite of these shortcomings, the waterjet's advantages are still weighty, and designs that could only be accomplished using one are increasing in popularity. "It's a moderately challenging technology," Bellilove says. "But architects, interior designers, and graphic designers are only just realizing that they have these options."

www.signindustry.com   By Charlie Fletcher