Waterjet: More Than A Nice Slice

January 6, 2005

Waterjet manufacturers say they’re seeing a huge boom in the use of their equipment in the stone industry – and it’s not only because of the technology’s clean-cut image.

The initial attraction to waterjet – or, more-properly, abrasive-jet machining – is still the ability to make both straight and curved cuts down to microscopic size utilizing computer generated files and very little water. But, manufacturers cite there’s a deeper appeal: versatility.

STRENGTH IN DIVERSITY

For anyone who’s added a bridge saw to the fabrication shop, the idea of buying what’s essentially another cutting device may not pop to the top when you’re listing what to invest in next.

However, the manufacturers of these systems say you may be selling waterjets – and yourself – short. The reason: while waterjets are also computer numeric control (CNC) machines, in many cases the Windows-based control systems are more-intuitive to operate than a tooled CNC machine.

“If you’re using a saw to cut, that saw is best suited for only straight cuts,” says Joe Blackmon, North American marketing and communications manager for ESAB Welding and Cutting Products in Florence, S.C. “A waterjet will give you very intricate, detailed cuts. If you’re doing intricate cutouts, the waterjet will allow you to do that. If want to cut small holes, you can do that with a waterjet, too, whereas with a router or saw you’re somewhat limited.”

Even if a shop is interested only in cutting stone products and, perhaps, an occasional piece of backing material, a waterjet makes smaller cuts with less vibration makes for better material use, says Mike Ruppenthal, director of marketing for Kent, Wash.-based Flow International Corp.

“We’ve found you can get up to 40-percent-more yield, and that’s especially important with expensive pieces of material,” he says. “You can nest multiple pieces of a job in a single slab because you don’t have to overcut like you would with a saw, or cut in as wide a cutting swath as you do with a CNC router. You can definitely increase a shop’s profit margin just from that.”

However, the manufacturers say where their equipment really shines is in its ability to cut materials well beyond granite and limestone.

“It gives people who have been doing only stone much-wider capabilities,” says Johnnie Howard, president of the Dallas-based Calypso Waterjet. “Waterjet will cut metal of all types; it will cut glass; in fact, it will cut just about any material you want to cut, and it will cut it very well.”

An important component of that flexibility is built-in software that allows the user to automatically adjust the machine to cut a huge range of materials. And, while there are no firm numbers of how many stone fabricators utilize waterjets for other purposes, they have the opportunity to go well beyond custom backsplashes or medallions.

“The more-successful people who are cutting other materials are expanding artistically,” says Ruppenthal. “They’re cutting metal for signage or architectural screens or whatever. Once architects become familiar with what a waterjet can do, it opens up a whole host of possibilities to let a stone fabricator really diversify a business.”

BEST SOLUTION?

Even if you’ve cutting a kitchen a day, and doing some other miscellaneous work on the side, a waterjet may have a place in your shop. A major question when weighing the merits of a waterjet is whether you have the volume of work to keep such a machine busy, or at least generate enough off of it to make a monthly lease payment.

Brody Fanning, a regional manager with Calypso, says there are some people in the trade who are happy doing a single kitchen every day and don’t want to go beyond that. Those are also people who probably aren’t going to benefit from having a waterjet.

“However, we’ve found the guys who are doing a kitchen or two a day and have bought a waterjet can quickly expand to doing three-to-five kitchens a day without adding a lot of labor,” he says. “They’re able to take the labor the waterjet replaces and start feeding parts to the guys doing the polishing, so they can double the work they do without hiring anyone.”

Shops doing large commercial projects may find their best solution is a waterjet with dual or even quadruple heads capable of doing mirror cuts to zip through projects such as condominiums or hotels. However, John Dedic, marketing manager for KMT Waterjet Systems in Baxter Springs, Kan., says smaller custom shops are where his company is seeing the most growth in waterjet sales.

“These people might have a lower volume of work, but they do more with the stone,” he says. “They also have a local presence where the volume is going to come from cutting and finishing. With a machine that offers good versatility and good reliability, it helps them open their markets.”

Still, it’s important to remember that a waterjet is not going to be the go-to tool in every situation, nor is it capable of replacing a tooled CNC, for instance. One manufacturer compares the relationship between a waterjet and a CNC production center to that of a knife and fork, with each serving its own necessary function.

John B. Cheung, president of Kent, Wash.-based OMAX Corp., says the waterjet’s specialty is cutting, and it’s not a good option when doing tasks such as polishing, profiling edges or making dimensional cuts, such as with drain boards.

“Waterjet is not very good at doing three-dimensional work,” Cheung says. “We recommend people don’t use it if it’s truly a three-dimensional piece. It’s also not for doing beveled edges, although in limited situation we can adjust the head to cut at an angle of up to 40° along a straight edge. However, you would not be able to do a bevel around a contour.”

EYEING THE MERCHANDISE

Buying a waterjet, though, may still be a challenge, with cost being only part of the evaluation process.

One consideration is size. The first abrasivejet machining systems were developed for the aerospace and defense industries; while manufacturers are recognizing the demand for these machines by the stone industry and sizing accordingly, some people may be tempted to save money by buying a machine with a table smaller than a standard slab.

“It depends on what you’re cutting,” says Cheung. “If you’re only cutting tiles, you might be okay with a 2’ X 2’ table. But, if you’re also cutting marble and granite slabs, I’d definitely suggest a 6’ X 12’ table.”

Ease of use is definitely in the eye of the beholder, and can include everything from how the slabs can be loaded and unloaded to the machine’s software package to how complicated replacement of the seals on the nozzle becomes.

When the issue is software, ESAB’s Blackmon says the goal should be ease-of-use between your software for templating and the conversion to a machine program.

At this point, many companies offer some sort of icon-based software system similar to Microsoft Windows, so that anyone with rudimentary software knowledge can be running the machine in less than a week. All the manufacturers include training with the installation of their machines, and most make advanced training availble at their own facilities.

Of course, not all manufacturers’ software programs are created equal. For instance, Flow likes to stress that its software is available in nine different languages, while OMAX, (which developed its own program) makes multiple copies available to buyers and is easily upgraded.

Some companies also offer related add-ons, such as Calypso’s job-estimating software.

While driving the machine is important, KMT’s Dedic says maintenance of the water-pumping system is something many buyers only consider once they’ve gotten a machine in the shop.

“The life of the seals should be a big consideration,” he says. “The time between failure on the seals on the machine and how long it takes to change those seals are extremely important issues.”

Also important, Dedic says, is the maximum pressure at which the machine cuts. While some waterjets cut at 50,000 psi (pounds per square inch), others work at 60,000 psi.

“Even though there’s only 10,000 psi difference between the two, the cutting speed is increased by 20 percent,” he says. “You can cut faster at higher pressure.”

Several manufacturers mention the importance of a feature that starts each hole cut at a lower pressure, then automatically increases it to avoid the chance of cracking or blowing out the hole.

Another feature that both Flow and KMT stress is one that helps the waterjet head avoid items that may pop up on the slab as it’s being cut, and have the potential to damage the nozzle as it traverses across the stone or throw the head out of alignment.

Some manufactures even have the ability to truly customize a machine for the buyer’s needs. For instance, Blackmon says ESAB’s machines can be built to incorporate multiple features under one CNC control. A popular one with metal shops incorporates a waterjet and a plasma torch in the same machine.

“We can also combine a router and a waterjet on the same machine,” says Blackmon. “If you’re going to do a kitchen you might cut the faucet holes with the waterjet and then run the router on the outside to profile the edges. You don’t have to move the work, and you’d have a single part program to combine the processes.”

FITTING IN

Unless you’re tying the purchase of a new piece of equipment – be it waterjet or something else – with a move to a new shop, the other question that has to be considered is how it will integrate into your existing floor space.

Again, it depends on the size of what you’re buying, but for many operations it shouldn’t be a problem.

“A typical 5’ X 10’ machine needs roughly an 8’ X 12’ footprint on the shop floor,” says Chris Reed, an engineer with Red Oak, Texas-based Perfect Technology Waterjet Co. (PTC Waterjet). “Of course, you need space around the machine for loading and off-loading material. Usually, the high-pressure pump, which requires approximately 3’ X 6’ of space, is housed nearby.”

Beyond that, the machines need what much of the rest of the shop’s equipment also requires: electricity, a water source and a wastewater-removal system.

Flow’s Ruppenthal says the electrical requirement of his company’s equipment is pretty common. Preference is for a 440v connection for the pump, but the machine can work with 220v and a transformer.

The need for water and the wastewater at the end of the process are a little different for abrasivejet cutting. Because a mixture of water and abrasive under high pressure does the cutting, the water use is low – but some purity is required. Waterjet manufacturers often sample the shop’s water supply before installation to see if it needs treatment.

Depending on what part of the country you’re in, a waterjet system may also require a chiller to keep the water temperature below 70°F. Where water is expensive, it’s also possible to reuse it.

“While a lot of shops have existing systems for recycling water, it typically isn’t good enough for our pump,” says Calypso’s Fanning. “But, we can recycle the water out of our pumps with a special unit. If necessary, it’s definitely possible to do a closed-loop system.”

However, all the manufacturers stress that the water used by these machines is minimal: one-to-four gallons per minute, depending on the machine. And, because the product coming off the machine is water, abrasive and stone particles, the waste may be able to be disposed of without treatment (although regulations may differ throughout the country).

ESAB’s Blackmon cautions that may change if the equipment is used to cut non-natural materials.

Many owners may not give them a thought when it comes to bringing a waterjet into the shop, but Sandra McLain, OMAX director of marketing, says the machines also have two other benefits for the shop environment.

“The fact that everything is cut under water means there’s not the dust in the air that you get from a bridge saw,” she says. “You also don’t get the noise you get from other CNC equipment. People can talk without raising their voices. It’s very quiet.

Get all the latest in the industry with The EDGE, the e-newsletter from Stone Update. Free subscriptions are available here.