An abrasive feeder gives this waterjet an edge

October 2011 - A singed edge on a metal part can make all the difference when constructing an aircraft. The heat-affected edge in an airplane can become brittle and break, leaving the component susceptible to nature’s elements. Or when drilling a well for oil or gas, internal components within pressure vessels must be sliced precisely to ensure water, oil and gas are separated properly. When engineers need a tighter tolerance or a precisely cut part, a waterjet is often the solution.

Pressure vessels constructed by North Texas Pressure Vessels Inc., Mineral Wells, Texas, often end up in Pennsylvania, Colorado, Arkansas, Louisiana and southern Texas. After a well is drilled, the vessels NTPV sells have internal parts cut with a waterjet and are used on well-production units. “We have a patent-pending design: the Sand Shark, a vessel that we build for the oil and gas industry that knocks out the sand after the wells are flowing,” says Keith Boyd, president of NTPV. “We cut all the internals using a MultiCam 3205-W with a 5 ft. by 12 ft. bed.”

NTPV’s pressure vessels are comprised of stainless steel, carbon steel and aluminum. The company works on jobs daily. “We’ve worked with MultiCam for two years,” Boyd says. “We upgraded and wanted someone we could depend on for service.”

Fabricators often go to NTPV with either a pre-drawn internal part or a request to have one of NTPV’s engineers draw a part. “It’s all done on the computer using MultiCam’s software,” Boyd says. “The designer could look at it on a computer and then put it up in a DFX file, which goes to the operator’s console, and that’s what tells the unit how to cut.

“You can convert just about anything you can draw to a DFX file, a nomenclature for a drawing,” Boyd continues. “The software recognizes it and can put it into a configuration to cut.”

MultiCam uses NC Geomate software, which the company developed specifically for its waterjets. Easy to operate, it comes standard with each machine. “You can import a DFX as well as other file formats and convert it to a CNC program in three easy steps,” says John Harris, director of sales and marketing, MultiCam Inc., DFW Airport, Texas. “You can have your part be ready to cut within minutes. You select from a series of graphic images to decide on the edge finish you want.” Harris adds the software is very intuitive and helps operators program the machine easily.

Venturing beyond vessels
Due to the versatility of the MultiCam waterjet, NTPV is able to expand its offerings to include products beyond pressure vessel parts. NTPV also works with a company that constructs antennas for the U.S. government. “We have to hold a really tight tolerance, so we cut aluminum and stainless steel for them,” Boyd says. “Some antennas are used in Naval ships [or] airports that go to government sites where they’ll be 50- to 100-ft.-tall antennas used for radios. We cut all the face plates and brackets for them to then mount.”

The company also manufactures filter separators and closures, which the waterjet cuts. The waterjet also is used to cut the internals for the filtersep and closure lugs. These units are used in chemical plants and pipelines for various liquid units for water, oil and sometimes gas, says Boyd. “We have different clients—we’ve built for Conoco Phillips, Exxon, EOG, among others. Us being able to do our own filtersep and closures and keeping cutting in-house gives us control. We don’t have to depend on someone else or worry that they’re being overworked or falling behind scheduled deadlines.”

The ability to make precise cuts under program control is because of MultiCam’s unique abrasive feeding system. “It’s extremely accurate,” Harris says. “Under CNC program control, we can measure and dispense very precise amounts of abrasive within a given program. The edge finish: many times, that’s critical, and you want more or less abrasive,” he says.

“We have large-scale CNC machines. The constriction methods we use are exceptional,” Harris says. “We have all the manufacturing equipment in-house, so we don’t have to send anything out. We stress relieve all our frames prior to machining, and we use premium, quality components throughout—we pay a lot of attention to detail. We’ve built over 9,000 machines worldwide and have been in business 22 years.”

More capabilities, less waste
Employing the use of a waterjet has expanded NTPV’s capabilities. “A company like Lockheed needs more precision for aircraft parts,” Boyd says. “They just can’t do with a plasma what they can do with a waterjet. We’ve been pushing to expand within the aerospace industry.”

When aerospace customers come to NTPV, they have drawings already made. “Aerospace customers don’t need us to do any kind of drawings because they know what they want,” Boyd says. “If they want 0.002 in. or 0.003 in. of clearance, we can do that.”

Harris emphasizes the need for scrupulous attention to detail when crafting parts for the aerospace industry. “Relative to plasma technology, waterjets are quite accurate and give such a beautiful, sanded edge,” he says. “It comes off the abrasive waterjet without needing any additional edging at all.”

Boyd adds using a waterjet results in less waste. “We like that there’s no clean-up,” he says. “It’s been a time saver for us. There’s no waste, and the garnet is just like sand. You can dispose of it naturally without having any special disposal. And there’s no smoke.

“Plasmas need filtration and fans to suck out the smoke,” Boyd continues. “It’s environmentally safer.”

MultiCam’s research and development team is working around the clock, Harris says. “We have five different product lines, and MultiCam will be introducing a low-cost waterjet at the Fabtech trade show in Chicago in November.” According to Harris, the new waterjet has been a development project that’s been underway for more than a year.

“It’s a very low price point for an abrasive waterjet,” Harris says. “We think this will open up all kinds of markets for people that only have need for a waterjet once or twice a week. This will completely open up waterjets for both our U.S. and international customers.”

While MultiCam’s research and development team always is looking to improve current products, the company “isn’t trying to fix something that’s not broken,” Harris says. “But things are constantly evolving. The machines we’re shipping out today are enhanced versions of machines we shipped out six months ago. Improvements are happening all the time.”

NTPV is “plenty busy,” Boyd says, adding the company is looking to increase its capacity by possibly purchasing a waterjet with 90,000 psi to 100,000 psi.

“That would give us a faster cutting area and faster cutting speed,” Boyd says. “We have clients who, before deciding to sign on with us, need to approve our shop first. They come in, see our waterjet and tell us they didn’t know parts were built ‘like that.’ Especially using our Sand Shark technology, it gives us a selling edge.” FFJ

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