A Texas fabricator takes on five-axis waterjet cutting
April 3, 2012
More fabricators haved jumped into flat waterjet cutting, so to attract new customers and carve out a niche around 3-D design and manufacturing, Maximum Industries, Irving, Texas, started five-axis cutting in 2011.
C’mon, try it. You’ll like it. Sure enough, that’s what waterjet technology vendors were telling metal fabricators over the last 15 years, and they bought into it. Today you would be hard-pressed to find a town with some sort of manufacturing activity going on that didn’t have waterjet cutting services nearby. A technology that grew out of the aerospace industry is now being used all across the metal manufacturing spectrum.
Rodie Woodard is a longtime fan of the technology, so he’s happy to see waterjet cutting emerge as a mainstream tool. He spent many years selling the equipment for Ingersoll Rand’s waterjet division, now known as KMT Waterjet Systems Inc., and he opened up his own shop, Maximum Industries, Irving, Texas, back in 1996.
Of course, waterjet’s widespread adoption also makes business a bit more difficult. Thanks to the advanced control technology and software, a fabricator can produce acceptable 2-D parts fairly easily, increasing the competition base for a limited number of jobs requiring that type of cutting service.
Maximum Industries has been able to stay ahead of the competition on the basis of its waterjet expertise. It knows the ins and outs of its equipment so that it can fabricate lower-volume specialty parts (see Figure 1) or high-volume production parts (see Figure 2) in a way that is most economical for the customer. It also knows which applications to walk away from because the company would have difficulty making its margin.
That expertise also motivated the company to enter a new dimension in waterjet cutting—full 3-D fabrications. It purchased its first five-axis waterjet in early 2011.
“We wanted to separate ourselves from the competition because so many people were entering the market with flat-stock waterjet cutters,” Woodard said. “With that kind of a situation, we said, ‘If we can do the tough ones, we can do the simple projects too. Why not both of them at the same time?’”
Woodard’s comfort with waterjet cutting comes from his many years of being around the technology. But he’s not just a waterjet expert; he possesses a great amount of overall metal fabricating knowledge as well.
When he first opened his shop in the mid-1990s, he purchased two waterjet tables, but he also invested in a laser cutting table. He sees them as complementary technologies. For cutting thin parts, exposure of the metal to a heat source doesn’t matter, and high production speeds are necessary, so the laser cutting machines make the most sense. For those jobs that call for high-tolerance cuts, material thickness greater than 0.25 in., or cold-cutting, the waterjets fit the bill.
Today Maximum Industries operates five waterjet tables and five laser cutting machines, ranging in power from 1,000- to 3,300 watts. The company also owns a couple of 200-W lasers for parts marking.
“We were all about service and marketing the capabilities and pushing the envelope. That’s led to the growth in all of our business,” Woodard said. “It’s being able to take on tighter-tolerance or not-so-easy applications with the technology. If you can do those and gain the customers’ confidence, you can do the easy projects too.”
The company added assembly, gas metal arc welding, and product design services over the years to respond to customers’ ever-growing requests. Even with the expansion in fabricating capabilities, Woodard knew that he needed to keep an eye out for his shop’s next evolutionary step.
“This has been an entrepreneurial evolution with opportunities that present themselves in the existing customer base as you grow that,” he said.
One of the first steps to prepare for that was moving into a new facility three years ago. The 44,000-square-foot building gave him the opportunity to organize equipment in a logical manner and allow for the addition of new equipment.
He soon added a three-axis waterjet from Romeo Engineering, the manufacturer of Maximum Industries’ three other 2-D tables. Now that table operates six to eight hours per shift cutting thick aluminum extrusions that require the cutting head to move up and over contoured sections of the part (see Figure 3).
Flat was the past. Three-dimensional forms were the future.
That led Maximum Industries to add milling and routing capabilities (see Figure 4) in the fall of 2010. Woodard said the company added three small milling machines and two large flatbed mills, one with a 5- by 12-ft. working envelope and another with a larger 7- by 12-ft. working space. Machinists were added so the new equipment’s capabilities could be fully utilized right from the start.
With the amount of aerospace business in north Texas, Woodard said he saw an opportunity to expand the customer base and establish a reputation for fabricating high-quality 3-D parts. However, Maximum Industries needed a five-axis waterjet with high-pressure pump technology to make the vision a reality.
Woodard said he elected to go with PaR Systems Inc. to supply the five-axis waterjet cutting system because the company had multiple installations across the U.S. He also chose a powerful pump combination—a 125-HP, 90,000-PSI pump from KMT Waterjet Systems.
Maximum Industries was no stranger to the KMT pumps. Woodard already had four other 60,000-PSI pumps (see Figure 5), which had been upgraded over the years with the latest “top works,” or mechanical parts responsible for delivering the powerful cutting stream.
Bryon Machado, KMT’s area manager for the South, said that this piece of equipment is one of the largest in the region and also one of the fastest. He estimated that it is at least 60 percent faster than a table driven by a 60-HP pump.
He added that the machine is a true five-axis machine (see Figure 6), capable of cutting 90 degrees, if necessary.
“What people are confusing with five axis is bevel capability,” Machado said. “People may call it five axis, but it’s not five axis. It’s a beveling-capable machine, where you can set a 45 or 50 percent bevel for weld prep and things of that nature.”
Woodard may have been new to five-axis waterjet cutting, but he was no newcomer to using a waterjet. He knew just how he wanted to approach the equipment:
Waterjet cut and drill on the same machine. “The people that have invested in five-axis waterjets have just five axes. Our five-axis has an integrated drill with it, so we can predrill composites and plastics,” Woodard said.
Work with composites may not be on the to-do lists for many metal fabricators, but when you enter the world of waterjet cutting, almost any material is a candidate to be cut with the high-pressure water stream. The problem with composites, however, is piercing the material with a waterjet.
When attempting to pierce composites, the waterjet not only breaks the surface of the material, but also works its way into the different composite layers, delaminating the material and ruining the structural integrity of the material around the hole. The drill alleviates this problem because it creates the initial hole in the composite material.
“We go over with a traditional drill that is integrated with the cutting head, and it predrills start holes, maybe 0.80 in. in diameter. [The cutting head] comes back with the waterjet to a known point … and pierces through without damaging the material during the cut,” Woodard said.
Keep the pumps running as much as possible. When Woodard was working for Ingersoll Rand in the Detroit area before making the move to Texas and setting up his own shop, he noticed how the automotive industry headered all of the waterjet pumps together along an assembly line, instead of connecting one pump to one table, which is typical of job shop setups. By connecting all of the pumps, those manufacturing engineers on the automotive assembly floor didn’t have to worry about stopping the manufacturing process if one pump went down for maintenance; the pump was taken offline, and the other pumps picked up the slack.
Let’s just say that Woodard never forgot that setup. Maximum Industries has always headered its pumps together—just like those automotive companies.
“In our case, we have enough capacity where if any two pumps go down, we can still run all five of our machines,” Woodard said.
The three- and five-axis tables are connected to the 90,000-PSI pump. All of the power from the pump can be applied to one table or can be split between the two tables.
Know when to apply the pressure. Just because Maximum Industries has a 90,000-PSI pump doesn’t mean it will run the waterjet at that level all of the time—although it might be tempting.
Machado said the higher-pressure pump allows a fabricator to cut more parts with the same amount of abrasive as a lower-pressure pump uses. For instance, a 60,000-PSI unit might use 1 lb. of abrasive per minute to cut parts, but the 90,000-PSI unit would cut twice as many parts while still using 1 lb. of abrasive. Considering that abrasives are about 60 percent of the operating cost for a waterjet, that’s a big deal, he said.
However, if a fabricator is leaning on the waterjet to deliver at the top of its performance range, more frequent maintenance will be required.
“Again from being behind the scenes from the manufacturer’s point of view, I know how the stress curves go on stainless steel parts in the waterjet world,” Woodard said. “If you are operating above 50,000 PSI with a 60,000-PSI pump, you do get faster cutting speeds as you go up in pressure … But if the system is designed for 60,000 PSI, your [pump] part life is much, much less than if you were operating at 48,000 PSI.
“We sacrifice a little bit of cutting speed, but the mean time between failures on every component in our whole system is drastically longer. So the downtime associated with any maintenance issues is almost nil,” he added.
That’s why Maximum Industries typically runs its 60,000-PSI pumps at 48,000 to 50,000 PSI and its 90,000-PSI pump at 78,000 to 80,000 PSI. The company might even run at lower pressures depending on the material being cut and level of part tolerance specified for the job.
While Maximum Industries waited for the five-axis waterjet to be delivered, it achieved AS9100 certification, which has proven to be very beneficial as the shop has attracted business for its newest 3-D metalworking capabilities. The certification, which is tailored for the aerospace industry, states that the manufacturer must follow a process-based approach to managing its quality efforts.
Woodard said the certification not only has helped the company become more disciplined in terms of documenting preventive maintenance programs and work procedures, but also helped it garner the attention of large aerospace companies. In fact, Maximum Industries may be in the position in the coming months of being one of a handful of companies chosen to use their five-axis waterjets to cut parts for the Joint Strike Fighter, the next generation of aircraft designed for the U.S. Department of Defense.
In the meantime, the five-axis waterjet isn’t sitting quietly; it’s used on a daily basis for complicated parts. Woodard described one such job in which 0.030-in. slits that were 0.75 in. long with a 0.040-in. gap between each slit were cut around a metal blank shaped like a lamp shade. The five-axis waterjet was a natural choice for the job because the waterjet nozzle had to be pointed horizontally at the titanium part as the cuts were made around the part’s exterior. He added that the fixturing for the job was just as complex, because not only did it need to act as a base for the titanium part as it was being cut, but also protect the back of the part from the waterjet stream as it cut through the front.
“We kind of market ourselves as a multiaxis shop … That’s probably where we are going—more 3-D projects,” Woodard said.
Meanwhile, most other fabricators that use waterjets are left to battle it out in the rough-and-tumble 2-D world.
Would you locate your waterjet cutting operation in the same space as your laser cutting operation without some sort of physical wall to divide the two activities?
Most fabricators wouldn’t think twice before saying “No.” Rodie Woodard, president, Maximum Industries, Irving, Texas, and former salesman of waterjet cutting equipment, advised his customers to set up a separate environment because the waterjet sprays so much water and metal residue around the table—not exactly the clean environment desired for laser cutting.
Now Woodard is a fab shop owner with 28 employees. And he didn’t exactly follow his own advice. His waterjet cutting operation is located in the same area as his laser cutting machines, albeit on opposite ends of the 44,000-sq.-ft. facility.
“When I was selling equipment, I would walk in [a shop] and see people walking around in rubber boots. It was like walking down a beach. You couldn’t see what color the machines were,” he said. “Ours is completely different. It’s like a machine shop as you walk around our waterjets.”
How does the shop floor stay so clean? A Zamboni®-like vacuum is run multiple times each shift, cleaning up the dust and residue from the floor.
The commitment to good housekeeping is apparently enough to keep the peace between the laser cutting and waterjet cutting machine odd couple.