The United States Army's armored personnel carrier is regarded by troops as a necessary evil. Vital to get soldiers to an engagement or around the battlefield quickly, the lightly armored APCs are also highly vulnerable.
Keith Doszak of Performance Welding, a Freedom, Wis. fabricator, welds side members of 3/16-in. steel for a heavy equipment manufacturer using the Miller Electric XMT® 350 CC/CV multiprocess inverter. The XMT 350 features Auto-Line® technology which boosts the primary power to a higher voltage to ensure the inverter has sufficient power regardless of voltage drops. The XMT 350 rode through low voltage situations created by dirty power from the local utility, says Kurt Wollenberg, vice president of Performance Welding.
No where has that become more evident than in Iraq. Whether moving across the desert or through villages, APCs have become a key target of Iraqi insurgents. Their weapon of choice is the rocket-propelled grenade (RPG).
A major defense contractor devised a system of hardened steel fins that are mounted to the sides of the APCs at a downward 45-degree angle. The fins deflect grenades away from the skin of the vehicle, where they explode without harming the soldiers inside.
To fabricate and weld the fins to mounting brackets that are bolted to the sides of the APCs, the defense contractor turned to two strategically partnered Wisconsin companies: Performance Welding, a woman-owned small business located in tiny Freedom, that specializes in certified welding services; and Val Fab Inc., a veteran service-disabled owned company in Neenah, specializing in custom metal fabrication. Their combined reputations for providing quality custom metal fabricated products, certified welding services and on-time delivery have allowed them to become preferred suppliers to numerous large manufacturers and defense contractors.
"Those fins are saving a lot of our men and women in Iraq from injuries or worse," says Kurt Wollenberg, vice president of Performance Welding. "I have some terrific fabricators working for me and their welding expertise, and the reliability of our equipment, is why we continue to receive defense contract work."
Performance Welding's fabricators rely on the XMT® Series of multiprocess inverters from Miller Electric Mfg. Co. Currently they use three XMT® 304 CC/CV machines and one new XMT 350 CC/CV inverter featuring Auto-Line™ primary power management technology. Wollenberg says, "Auto-Line performs as advertised. The XMT 350 has shown the ability to ride through voltage drops, which can shut down the 304s, and maintain a steady arc. That was critical during the APC fin project. We had to fabricate 188 sets of fins, a left and a right unit, in a three-week window."
Fabricator Tim Hallada says Auto-Line technology ensures him that his XMT 350 CC/CV inverter will maintain a steady arc even if Performance Welding encounters an unanticipated power drop.
The fin project is just the latest job Performance Welding has tackled for the Defense Department, through its partnership with Val Fab. "Both of our companies qualify as diversity approved contractors with the government," Wollenberg explains. "We qualify because my wife, Carmen, is the president of the company; in Val Fab's case, the head of the company is a disabled veteran.
"But although that 'diversity' designation might get us in the door, I know it's the quality of our work that keeps the projects coming in," he says. "We handle the repetitive work while Val Fab does the large pieces. The big defense contractors know they can count on both of us."
Working through Dirty Power
Performance Welding's rural location has presented the company with some formidable power problems. Before relocating to Freedom, the company was in nearby Little Chute, where its power was hydro-generated from the waters of the Fox River. Dirty power was a constant concern. On numerous occasions, the unreliable hydro-power would dim the lights in the shop.
During the APC fin project, the problem became plainly evident when a voltage drop caused two of the three XMT 304s on the job to register low incoming voltage readings and shutdown for self-protection.
"But the XMT 350 with Auto-Line never hiccupped," Wollenberg says. "We were running 350 amps at 27 volts, 60 percent duty cycle, welding 3/8-inch hardened steel, and every piece met the defense contractor's tolerances of plus-or-minus 3 millimeters. The ability of the XMT 350 to ride through the voltage drop that shut down the XMT 304s was proof-positive to me of Auto-Line's benefits."
Even in a new location with more reliable power, Wollenberg says Auto-Line provided an advantage. During a winter storm, a power line crashed down across a major highway, causing the power grid to his facility to momentarily stumble. Again, his XMT 304s registered low incoming voltage readings and shut down, but "the XMT 350 rode through like a champ," he says.
Auto-Line technology, unique to Miller Electric, provides fabricators with three key benefits that improve welding performance: the ability to maintain a steady arc despite primary power fluctuations within a 190 to 630V range; a primary power draw of just 17.8 amps at rated output of 460 VAC primary (a 25 percent advantage over competitive inverters); and the flexibility to accept any type of primary power – 190 to 630V, single- or three-phase, 50 or 60 Hz – without any physical linking mechanisms. To put things in perspective, the line voltage compensation for the XMT 350 with Auto-Line is not just the industry standard of plus-or-minus 10 percent. Rather, it is plus 37 percent/minus 59 percent of the nominal 460V power. This wide tolerance is unheard of in the industry.
XMT 350 the Primary Inverter
Since Performance Welding could not afford inverter shutdowns while fabricating the APC fins, plant manager Keith Doszak says the XMT 350 was their primary machine during the project. "Re-work was not an option on this job.
Tim Hallada of Performance Welding welds pipe of rolled steel using the Miller XMT® 350 CC/CV multiprocess inverter. The XMT 350 features Auto-Line® technology which boosts the primary power to a higher voltage to ensure the inverter has sufficient power regardless of voltage drops.
"All of the heavy welding was with the XMT 350 and it performed beautifully," he says. "We were running 14 hours a day straight for those three weeks, except for Sundays, which were eight hours. We had six guys welding full out in two assembly lines; one to tack weld, one to weld the stainless steel boss to the mounting bracket, and the third guy welded the hardened steel fin to the boss. We were burning the coals on that job."
Performance Welding selected 309L .035-in. diameter wire for the stainless work. For the high-tensile steel, Doszak says they selected ER100 wire at .045-in. diameter. "We experimented with .035 and .045 ER100 wire, running C5 gas (95 percent argon/5 percent CO2), and we found we gained a lot of time by going to the .045 wire," he says. "We ran between 400 and 450 inches per minute and still maintained the contractor's tolerances. The welds were beautiful."
Cycle time of the XMT 350 was also critical, according to Doszak. "The longest weld we made on the fin project was about three inches, most of the work was a two-inch stitch every two inches, so we made ourselves spreader bars with tick marks every two inches to mark the weld spots," he says. "Once we got going we could really move quickly along the mounting brackets; we had no problems with the cycling of the XMT 350." A high number of On/Off cycles places a lot of stress on welding machines, so it is one of the better performance indicators.
Meeting Tight Tolerances
As quickly as his fabricators had to work, Wollenberg says the contractor's inspection process was the most important aspect. "To ensure that quality procedures were being consistently followed, the initial five pieces – and randomly selected pieces thereafter throughout the process – were inspected by a military-certified inspector using a Coordinate Measuring Machine."
Each mounting bracket contained eight deflector fins. If each fin's positioning was off by as little as one millimeter, the entire piece would be eight millimeters out of tolerance. According to Wollenberg, the contractor's blueprints called for no more than three millimeters of leeway per
piece. "Every one of the mounting brackets we fabricated was within tolerance. And every fabricator credited the XMT 350 for the precision of the welds."
The Wollenberg's recent move to Freedom provides Performance Welding with a four-acre location that will allow the company to grow its manufacturing facility. They have also spun off a new company, Performance Products, which manufactures and markets snowmobile lifting machines and sled display stands. As they continue to grow, Wollenberg says he will only consider Miller Electric inverters with Auto-Line.
"In our rural location, primary power will always be a concern. By specifying inverters like the XMT 350 with Auto-Line technology, we'll be able to specify smaller fuses and breakers, and smaller wiring, in our facility," he points out. "And we'll be able to add more welding machines without looking to boost our incoming service."