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The pressure’s on

Faster and more efficient waterjet cutting helps make the case for 90,000 psi

by Jimmy Myers, senior editor

 

 

A hard-driven car has been pushed to its limits and perhaps beyond. If a car is going to last, it’s best to be conservative and not put the pedal to the metal.

 

The same goes for waterjets. To avoid running their equipment into the ground, some fabricators using waterjet technology take the same conservative approach. When it comes to running at the industry standard of 60,000 psi, these fabricators will dial it back in order to save on consumables and the life of the machine.

 

“That has been the conventional wisdom,” says Bob Pedrazas, marketing manager at KMT Waterjet, in regard to using less power than is available. “But with technological advances, the new standard is to power up to 90,000 psi.”

 

Since 1971, KMT has made significant patented advancements in waterjet pump technology by offering two 90,000-psi waterjet pumps (60 hp and 125 hp), so KMT definitely has something to say about putting the “pedal to the metal.”

 

It’s understandable how someone might flippantly say, ‘it’s going to cost you more money to run at full speed,’ but KMT end users cutting at 90,000 psi concluded it actually saves on abrasives and reduces the need for overtime because parts are cut so much faster.

 

“You’re using 50 percent less abrasive because you’re cutting that much quicker,” Pedrazas says. “The point of manufacturing is the more you cut, the more you’re going to sell. If you’re using consumables and you’re spending a couple dollars more, then what the heck – let’s cut some parts.”

 

Pedrazas says he’s seen a “significant increase” in the last six months with fabricators coming to KMT about upgrading their 60,000-psi pump to the 90,000-psi pump, some pairing it with dual heads for faster cutting.

 

“The economy is picking and there is a need for more capacity,” Pedrazas notes.

 

He says the company estimates that if a manufacturer is cutting for eight hours a day, they can save around $30,000 in abrasives (garnet) per year by upgrading to a 90,000-psi system, which means it could pay for itself in five years.

 

“It’s money in the bank,” Pedrazas quips.

 

 

More manufacturers are moving from a 60,000-psi pump to one that offers 90,000 psi, and they’re improving production in the process.

 

 

Customer feedback

Rather than just take his word for it, Pedrazas suggests potential customers check out company videos with client testimonials about what they experienced when making the jump from 60,000 to 90,000 psi.

 

According to Rodie Woodard, president at Maximum Industries, a full service, piece-part production and contract manufacturing facility, the cost was justified in replacing its 60,000-psi pumps with the 90,000-psi pumps.

“It’s a slam dunk,” he says. “Faster cutting speeds means more throughput.”

 

Furthermore, using less abrasives means less cost upfront and on the back end, as well, considering spent material has to be disposed of. Those savings either go straight to the bottom line or allow a user to offer more competitive pricing, Woodard says.

 

Woodard also finds that the waterjet orifice stream quality is much better with the more powerful pump – it’s “tighter,” he says and, additionally, tolerances are improved, which opened up his company to new applications.

 

“The higher quality allows us to gain new business that we weren’t able to achieve before,” he says.

 

Krando Metal Products, another company that has adopted the 90,000-psi unit, bought its first waterjet machine in 1996 because it could “cut anything,” according to Tony DiAngelus, the company president. As soon as the 90,000-psi unit became available, he jumped on it.

 

“Going to the 90K,” he says, “upped our cut rate 65 to 70 percent, which means I can get twice as much work through this machine than I could with the 60K pump. We’re almost as competitive with laser technologies by using this machine.”

 

DiAngelus says his company sees many designs from customers that actually require a waterjet cut because analyses that have been done on laser cut parts have been found to warp or have stresses, fractures, cracks or issues with the edges being brittle.

 

Replacing the seal in the pump, which DiAngelus estimates is probably one of the most often replaced consumables for waterjet systems, has been made easy by KMT. It only requires 15 minutes of downtime to replace.

 

“Our downtime is minimal,” he says.

 

 

 

 

Is 90K for everyone?

KMT sells around 20 types of pumps with various combinations of horsepower and psi – from 15 hp to 200 hp. Most of the waterjet pump models range from 55,000 psi (direct drive) to 60,000 psi (intensifier) to two models offering the 90,000-psi (60-hp and 125-hp) pressure.

 

KMT’s customers are involved in a variety of industries, including stone cutting, that don’t need anything over 60,000 psi so there will always be a need for a lower powered pump. There is no reason to increase pressure and velocity, especially in water-only cutting applications, Pedrazas concluded.

 

“We really believe we’re the experts in what you should be cutting with in terms of pressure,” he advises. “We are advocates of cutting at 60,000 psi, but it really comes down to throughput, lower cost per part, an increase in capacity, the reduction of abrasive usage and how much you’re cutting in a day.”

 

Pedrazas says that if you’re a small job shop cutting one or two hours a day and only one or two inches of material, “60,000 psi is the way to go. There is no reason to buy a Lexus when you’re a kid. A Corolla is fine. We’re absolute advocates of determining what’s the right solution for you.”

 

For a manufacturer using a waterjet machine for six to 10 hours a day while consistently winning larger contracts, staying with a pump that is too small could create a backlog.

 

“Then you need to be thinking about 90,000 psi,” Pedrazas says. “If you’re working 16 hours in a day, cutting 2-in. to 4-in. material, you need to be looking at 90,000 psi with dual cutting heads.”

 

 

A clean, quality cut leads many designers to require all cuts be made with a waterjet rather than a laser.

 

 

Focus on service

KMT is one of the only waterjet companies that showcases its service vans at tradeshows, such as Fabtech. It’s a point of pride for the company, which has fully stocked service trucks strategically positioned across the United States able to offer next-day service to customers.

 

As DiAngelus says in his testimonial, “KMT has a reputation to not leave you stranded.”

 

The company also has a reputation for its seal warranty. Pedrazas says KMT is the only waterjet pump manufacturer that offers a warranty on its seal life. The Streamline Pro III series 90,000-psi model, for instance, comes with a 500-hour seal life guarantee.

 

KMT has many service trucks in the field, which positions them perfectly for next-day assistance to any part of the United States.

 

 

“There is no one else in the industry that has any guarantee on seal life,” Pedrazas notes. “We’re the only ones that do it because we offer patented technology. I’d say that’s a commitment to genuine service.”

 

Another KMT offering is an app for fabricators to use to determine how fast they can cut through material. The KMT Pro III calculator in the app has fields for material type, abrasive type and material thickness. Someone cutting Inconel with a thickness of 1 in. with a fine edge quality, for example, can expect to see a significant increase in linear cutting speed with a 90,000-psi pump compared to a 60,000-psi pump.

 

KMT Waterjet

 

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