Cutting Tool Engineering
June 2010 / Volume 62 / Issue 6

To the max

By Daniel McCann

Max I.tif
Courtesy of U.S. Army
Max II.tif
Courtesy of Maximum Industries

The U.S. Army’s MRAP vehicles feature V-shaped hulls to divert blasts away from the cab. Maximum Industries machined a key part for the MRAP vehicle (above). Maximum Industries has five waterjet cutters (below), including a 90,000-psi machine with a 5-axis system.

Texas shop’s waterjet cutting capabilities help protect U.S. soldiers.

An abandoned soccer ball, half deflated, sits on an Iraqi roadside; farther on, an 8 " pile of flat, gray rocks, stacked in studied disarray, hugs the curb; up at the junction, on the right, a four-legged carcass lies beneath a thin cover of dirt and sand. All seemingly innocuous, but potentially deadly objects.

In 2007, camouflaged roadside improvised explosive devices (IEDs) and those borne by vehicles and suicide bombers accounted for 70 percent of U.S. casualties in Iraq. U.S. Army Humvees, with their wide, flat bottoms a mere 16 " off the ground, were especially vulnerable to IEDs. To remedy the problem, the Pentagon ordered that the Humvees be replaced with Mine Resistant Ambush Protected (MRAP) vehicles, featuring composite hulls with ¼ "-thick armor plate bonded to ½ " of Kevlar and 0.0060 " of steel. With 30 " of ground clearance, the V-shaped bottom diverts explosives.

Solving Problems

As with any newly designed product, the MRAP contracts called on truck builders and their suppliers to adapt their manufacturing processes and, in some cases, tackle unanticipated challenges. When one of those challenges arrived at the doorstep of Maximum Industries Inc., Irving, Texas, the company had already established itself as a shop committed to using the latest manufacturing technology to remedy knotty problems.

Founded in 1996 in a 6,000-sq.-ft. plant with three employees, Maximum today has 23 people working in a 44,000-sq.-ft. building. While a sizable portion of the company’s work involves waterjet and laser cutting, it also provides routing and milling, laser marking and engraving, welding, kitting and product design.

“We started out with two CNC waterjet machines and one small laser capable of cutting plastic and other nonmetals,” said Rodie Woodard, owner of Maximum Industries. In addition to four cutting lasers and a variety of machining centers, the company’s waterjet equipment includes four Gold Series gantries from Romeo Engineering Inc., Fort Worth, Texas, with work envelopes of 4 '×8 ', 6 '×10 ', 6 '×12 ' and 8 '×14 '. Each of the machines has a 50-hp, 60,000-psi SLV intensifier from KMT Waterjet Systems, Baxter Springs, Kansas. The intensifiers are headered together into a manifold system designed and installed by Maximum Industries. “More recently, we’ve added a fifth intensifier, a 125-hp, 90,000-psi KMT waterjet intensifier,” Woodard said. “That machine is integrated with one of our gantries that we’re upgrading to a 3-axis machine. This modification and upgrade will diversify our family of motion systems to three 2-axis systems, one 3-axis system and one 5-axis system.”

Quality and Technology

Maximum’s commitment to incorporating the latest waterjet cutting technology, along with continually meeting new quality standards—including AS 9100 and ISO 9001—have allowed the company to provide sophisticated waterjet cutting services to a widening range of markets, including the oil and gas, medical, semiconductor, aerospace and defense industries.

By early 2008, when Maximum took on a project modifying MRAP vehicle cab floorboards, it could call on a range of waterjet cutting resources and expertise. Still, the project proved to be among the most challenging in the company’s history, according to Woodard.

The original cab floorboards were contracted with an Israeli company that unfortunately shipped 500 formed assemblies to the U.S. with an incorrect hole pattern for mounting the seats.

“It was impractical to crate them to ship back to Israel, so we were asked to make six additional holes in each floorboard,” Woodard said. “It was a challenging application because the material was already formed with different materials bonded together, and it wasn’t flat.”

Milling or laser cutting the layered Kevlar and armor plate wasn’t feasible. “Each material requires different parameters and tooling to machine the holes,” said Woodard. “Laser cutting composite materials of this thickness does not work well at all. However, an abrasive waterjet easily cuts layered material with different materials.”

The key challenges were lifting and placing each 80 "-square, 750-lb. floorboard in a work cell, fixturing the devices and locating the six 1 "-square holes that needed to be cut in each part.

Each part was lifted with nylon strapping that hooked into fabricated lifting eyes on the assembly. Forklift extensions were used to lift the assemblies over a waterjet work cell. Because the floorboards were formed in the shape of a truck floorboard, Maximum had to remove the flat grating at the top of its 36 "-deep waterjet tank. That way, the height of the bridge, where the cutting head is, could be positioned over the section of the subassembly to be cut.

Custom Workholding

Fixturing for the floorboard consisted of a 2 "×4 " aluminum bar shaped like a saddle attached to the top of the waterjet tank. “Using the forklift, we placed the parts on to the fixturing. Because the parts had formed—not flat—bottoms, we needed special locating points in the fixturing that we set the parts on to,” Woodard said. “It all had to be done very gingerly.”

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An aircraft vent cover waterjet cut by Maximum Industries from 0.135 "-thick Inconel. The web thickness between each hole is 0.012 " to 0.017 " wide (seen in photo below).

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As previously noted, locating the six holes to be cut was also difficult.

“When you waterjet a flat piece of material, you usually cut the internal dimension of the part and then the external perimeter, so you can actually locate the holes to the edge of the part or exactly where they need to be,” Woodard said. “But on this job, because they were weldments, there would have been no way for us to locate the internal holes from the edge of the parts. When you bend steel and weld it, the parts won’t be exactly the same, like machined parts would be.”

That required Maximum to work from one of the existing internal holes because the additional cuts had to be accurate in relation to those holes and not necessarily the part’s outside edge, according to Woodard. “So we made cut files [CNC software files] in relation to an existing internal hole, then located our starting point from that hole and started the cutting process.”

The company used a 60,000-psi KMT waterjet with a 0.014 "- dia. diamond orifice, a 0.040 " focusing tube and about 1 lb./min. of garnet abrasive. Although cutting involved only 1 minute per hole (six holes were needed in each of the 500 parts), the process of loading, locating holes in each floorboard, cutting and unloading took about 15 minutes per part.

“We had the right processes in place to handle the problem, and it turned out to be a very successful project,” Woodard said.

Keys to Growth

While the MRAP job illustrates Maximum’s waterjetting capabilities—a central component of the company’s success—also key to the firm’s continued growth have been strategies aimed at combining various technologies to meet customers’ needs. The company’s machining and laser cutting services, for example, have boosted its waterjetting contracts because some jobs are best tackled with multiple technologies.

“A lot of our projects require waterjet cutting, and then they need countersinking or tapping or counterboring,” said Woodard. “We can handle those projects in our machining centers.” He added that lasers are making great strides in the type of materials they can cut. While waterjets can still cut almost anything, they may not achieve the lowest cost per part or the highest quality. “For instance, you can cut 10-gauge steel with a waterjet at 15 or 20 ipm, but with a laser, you’re cutting at 80 to 100 ipm, with much tighter tolerances,” Woodard said. “So, if we’re competing with other shops that have only waterjets, lasers can handle some jobs much better.”

Two more pieces of the company’s strategy have been its emphasis on employee versatility and redundant equipment. “We’ve been very lean for quite a while, and we’ve been able to do that and maintain competitiveness by cross training our people,” Woodard said. He added that automation allows one person to run multiple machines, such as operating one machine cutting 2 "-thick stainless and another cutting ⅛ " aluminum. “They can do that because the stainless runs so slow; it’s almost like waiting for water to boil. The operator can check on it every 5 or 10 minutes while paying more attention to the aluminum job that’s running 20 times faster.

At the company’s inception, Woodard realized that its success depended on service. “And we knew that if there was any downtime associated with our equipment, it would affect the quality of service we provide our customers,” he said. “So going forward, we made sure we had redundancy in all of our processes. If we wanted a laser, we made sure we purchased two lasers, for example. We did not want to be the shop that tells customers their parts aren’t ready because the equipment is down.”

The company’s service focus played a large part in helping it achieve 20 to 30 percent annual growth until 2008, when the recession eroded those sizable gains.

Nevertheless, the firm continues to gain new contracts to replace lost business. “It’s definitely about diversifying,” Woodard said. “The neat thing about waterjets is that you can cut so many different materials and go after applications in many markets. When one market is down, there are usually others doing well. If the economy is hurting and they’re having a lot of bank buyouts, they’ll be redoing signage on thousands of bank buildings, so we’ll concentrate on that market. You just try to hit the hotter markets.”

Recently, Woodard’s emphasis on expanding into niche markets provided the impetus for company executives to exhibit at the December 2009 PowerGen International convention in Las Vegas. “With our new 5-axis waterjet cutting system, we’re planning on pursuing applications in the power generation market,” Woodard said. “That machine and an AS 9100 quality management system will help us support the customers and unique applications this market presents. Basically, it’s a new challenge we’re ready to take on.” CTE

About the Author: Daniel McCann is senior editor of Cutting Tool Engineering.


For more information about Maximum Industries Inc., call (972) 501-9990 or visit www.maximumind.com.

Editor’s Note: To view a video about Maximum Industries’ waterjet operation, go to www.maximumind.com, select “About Us” and click on the video at the top of the page.

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