Get your feet wet: Drilling Performance

Abrasive waterjet cutting machines are flowing into small shops as complementary equipment.

Job shops looking for a relatively low-cost, small-footprint option to produce one-offs and small runs should consider an entry-level abrasive waterjet cutting machine.

Many such shops have already jumped onboard the waterjet wagon to accommodate customers who are starting to request waterjet-cut parts, according to John Cheung, president of waterjet machine builder Omax Corp., Kent, Wash.

“Waterjet is one of the fastest-growing systems in the machine tool industry,” said Brian Kent, global product manager for waterjet machine manufacturer Flow International Corp., Kent, Wash.

Courtesy of KMT Waterjet

Two KMT Waterjet Autoline cutting heads cut 0.25″-thick aluminum at 60,000 psi using the Streamline SL-V 50-hp pump.

“The speed and versatility of waterjet make it popular for small job shops,” Kent added. “It can cut practically any shape or material, which is important to small shops because they don’t know what kind of work is coming through the door the next day. It could be stainless steel today and plastic tomorrow. Also, turnaround time is becoming more critical in the U.S. as we do more reshoring, and the versatility of a waterjet really adds to its efficiency.”

Materials commonly cut with a waterjet include steel, stainless steel, aluminum, titanium, rubber, foam, plastics, composites, stone and tile. The only materials that typically cannot be cut are tempered glass (because it can shatter on impact), diamond (because it is too hard) and certain brittle ceramics.

“Water doesn’t know what it can’t cut,” said Bob Pedrazas, marketing manager at waterjet pump and cutting head manufacturer KMT Waterjet Systems Inc., Baxter Springs, Kan. “It doesn’t discriminate. Water can be very powerful—it did a pretty good job cutting the Grand Canyon.”

As more job shops seek smaller, less-expensive waterjet machines, waterjet machine manufacturers are meeting those needs.

“The number of new waterjet systems, in general, has conservatively doubled in the last 5 years, with an annual growth of 15 to 20 percent during that time,” Pedrazas said.

Why Waterjet?

It’s the waterjet’s versatility that has boosted its popularity among job shops because it complements the other machines on the shop floor.

“End users continually mention that their waterjet systems are the most versatile machine tool in their facility because of the variety of materials the system will cut,” Pedrazas said.

But waterjets won’t necessarily replace other technologies because there’s not one system out there that can do everything perfectly, according to Pedrazas. He added that what laser and plasma cutting machines can’t perform, a waterjet can.

While a laser can cut parts faster than a waterjet, lasers generally cut up to a maximum of 1″ in some materials and reflective materials are problematic. Some waterjets can cut up to 15″ of steel and all can cut reflective materials.

Courtesy of Miro Tool

A Miro Tool operator cuts a stripper plate for a progressive die for the lawn and garden industry.

Plasma machines also have their limitations, as they create heat-affected zones along the cut edges that can require secondary operations, such as grinding, to remove, according to Omax’s Cheung. In contrast, waterjet cutting is a cool erosion process so it does not create a HAZ.

Jeff Brown, owner and president of job shop Miro Tool & Manufacturing Inc., Waukesha, Wis., explained why his shop invested in a waterjet. “As we branched out more into the manufacturing world, we added a waterjet to complement our other systems, particularly the wire EDM, which is expensive to operate because parts take longer to cut, and the CNC machine, which is time-consuming because it requires more setup time,” Brown said.

Miro Tool has two Mitsubishi 6′ × 12′ waterjet systems with KMT pumps that cut material up to 6″ thick at 90,000 psi.

According to Brown, a CNC machine is better than a waterjet for full production runs, but the waterjet is preferable for quick-turnaround jobs. “You can cut anything with the waterjet. We’ve used it on stainless, marble, ceramic, aluminum and hardened steel,” he said, noting CNC machines and wire EDMs are limited on the types of material they can cut.

A waterjet can be effective for certain large runs. To produce an order for 34,000 stainless steel flange plates, for example, Brown uses a waterjet because it’s faster than the CNC machine. He noted the types and thicknesses of some materials can make a CNC machine inefficient.

For Brown, determining which type of machine to use depends on the part shape, the type of material and its thickness and the tolerance specification. “Anything you want to cut with a tolerance that’s ±0.005 “—in many instances, the waterjet can be the best solution,” he said.

Blast of Benefits

Waterjet systems also are becoming more attractive as the technology evolves while prices come down.

“Five years ago, I wouldn’t have bought a waterjet system because its accuracy didn’t meet our customers’ standards,” Brown said. “I sent some product out to get water-cut 5 years ago and the system just couldn’t hold the tolerances required by our customers.” But as waterjet technology continues to improve, the speed and accuracy of current waterjet systems have changed his mind.

Courtesy of Omax

Camm Metals, East Windsor, Conn., uses three Omax waterjets to cut parts for aerospace and architectural customers.

Courtesy of KMT Waterjet

A KMT NEOLine 40-hp, 55,000-psi pump is used to cut aluminum. Waterjetting does not create a heat-affected zone.

Depending on the operating pressure of the pump, which ranges from 50,000 psi to 120,000 psi, a waterjet can cut up to 15″ of steel or workpieces as thin as paper.

“Once you get into the waterjet game, you find all kinds of things you can cut. I’m keeping two waterjets busy all the time—one running almost 24/7,” Brown said.

The versatility of waterjets can generate new revenue streams for small job shops. “With a waterjet, they can accept jobs they otherwise would have had to turn away,” Omax’s Cheung said.

Flow’s Kent concurred. “Adding a waterjet allows shops to bid larger projects that use their combined capabilities,” Kent said. “When multiple operations are involved, using a waterjet can make the entire [manufacturing] process more efficient.”

For example, Kent cited a customer that was plasma cutting an aerospace part, which then required several secondary operations. After switching to waterjetting, which takes longer than plasma cutting, the shop still went from making the part in 27 minutes to 9 minutes by eliminating some secondary processes.

Also, turnaround times are critical, particularly for a small shop outsourcing its waterjet work and relying on someone else for setting turnaround time, according to Scott Wirtanen, northeast regional manager, Boston, for waterjet machine builder Jet Edge, St. Michael, Minn.

“If a shop invests in an entry-level waterjet system and starts doing its own waterjet cutting, it controls its own lead times,” Wirtanen said.

Also, waterjets reduce operator requirements, according to Miro Tool’s Brown. “You can run it unattended, which makes it more profitable,” he said. “That’s why we bought a second machine. One guy can program and run two machines and then still go do something else.”

Worth the Cost?

Research is required to find the type of machine that best meets a shop’s budget. Expect to pay around $80,000 to $125,000 for a small (4′ × 4′ table), entry-level waterjet machine and up to $200,000 to $400,000 for a larger (5′ × 10′), more sophisticated one.