Advanced TIG, pulsed MIG processes improve speed and performance, and reduce power draw, for producing highly engineered aluminum (6061 and 356) components.
Tim Orchard, president and owner of OMF Performance Products founded his Riverside, Calif., company 28 years ago out of necessity. The longtime off-road racer wanted more choices for high-performance custom wheels. The same man who raced alongside Bobby Unser Jr. at Pikes Peak also learned a good deal while working in metal stamping and sheet metal fabricating operations, and decided to put that knowledge to work.
“There weren’t enough reliable, quality products with good delivery times available to market being,” says Orchard. “So, I slowly eased into it. It started off as a sideline for the first few years, and then it got so busy that I had to go full time.”
Once Orchard went all-in, he equipped his shop with enough welding and fabricating equipment to keep his operations loose: he can make running changes and custom fabricate to customers’ needs, but he eventually became hamstrung by the power draw and strength of his 350-amp transformer-based welding equipment. Running off 208-volt three-phase power, Orchard was able to upgrade to a 700-amp TIG inverter with advanced AC TIG controls and add a 350-amp pulsed MIG welder — all while increasing welding speeds and reducing power consumption.
Aluminum wheels lock in racing performance
OMF’s high-performance racing wheels are used by all types of racers, from weekend warriors on quads to professional sand drag racers, and off-road teams, like rock crawlers, dune buggies and rhinos. The company’s premier technology is its bead-lock design. Air pressure typically is the only thing that holds a tire on the wheel — a problem when off-road racers prefer to run at lower pressures to gain traction as a performance advantages. OMF’s bead-lock technology mechanically fastens the tire to the wheel and creates an airtight seal that makes it impossible for the tire to come off the wheel. Each wheel, including the inner and outer rings that are welded on to create the supporting structure for the bead lock, is built from 6061 T-6 aluminum.
“We use 6061 T-6 for its strength and weldability,” says Orchard. “It’s the strongest commercially available alloy that is readily weldable. There are other alloys that are just as weldable, but not strong enough, and other alloys that are stronger but aren’t weldable.”
OMF outsources its polishing, plating and powder coating, but all machine work, assembly and welding is performed in-house. The company relies on an impressive combination of CNC machines, extrusion dies, and forging dies to create each wheel, and inverter-based welders to weld on the inner and outer rings: Miller Electric Mfg. Co.’s Millermatic® 350P pulsed MIG welder and the Dynasty® 700 advanced AC/DC TIG welder.
Pulsed MIG increases weld speeds by 35 percent
“Most of our bigger wheels — 14 in. and above — are 356 aluminum castings that become a huge heat sink. We found it almost impossible for any welder to keep up with it until the Millermatic 350P. The fact that it has built-in pulsing capabilities is huge for us.”
Larger aluminum wheels weigh in excess of 30 lb. and are cast in 356 aluminum in thicknesses ranging from 3/8-in. to 3/4-in. Welding the larger (14-in. and up) wheels with the old 350-amp TIG machine required preheating with an oxyacetylene torch up to 400 degrees F. For a time, OMF even used an oven before concluding that was too difficult to maintain.
“We’re probably 30- to 35-percent faster now. No preheating whatsoever. Of course, when we were TIG welding with the older machines, we would have to tack the pieces together and physically preheat them with an oxyacetylene torch, and then weld them. All that is gone from everything we do now.”
Pulsed MIG eliminates or minimizes burn-through, distortion, heat-affected zone size and loss of mechanical properties. Because aluminum quickly transfers heat from the weld, it takes more energy to establish the puddle, ensure good fusion through a pulse of peak energy, and control heat input (hence the previous need to preheat while TIG welding to regulate temperatures). Pulsed MIG also provides excellent directional control over the weld puddle and allows the operator to control the appearance.
“The casting is so big and rigid and heavy, it’s not going to deform. That’s the least of our worries. But the problem that we would have before the 350P technology was that the wheel would be wicking away heat, dissipating heat so quickly, that it was difficult to run at any real production speeds. The welding machines of the past just didn’t have the horsepower to keep up with this kind of weldment. The 350P has the horsepower to keep putting enough heat in the wheel the whole time so we don’t lose anything. As much as the wheel tries to dissipate the heat away, the 350P can stay ahead of it.”
In addition to the faster production speeds and the reduced hassle on the front end, pulsed MIG also creates less agitation (hence less spatter) in the weld puddle through modified spray transfer. Ultimately, bead appearance is similar to that of TIG. And features such as Aluminum Pulse Hot Start™, designed to eliminate cold starts when welding aluminum, automatically provides more welding power at the start of the weld and then reduces power to normal parameters for optimal welding characteristics from start to finish.
More weld power, more speed with smaller TIG inverter
On OMF’s smaller wheels (12 in. and below), Orchard previously ran a 350-amp squarewave TIG machine that would draw 110 amps off the shop’s 208-volt input power. According to Orchard, the previous machine maxed out at about 25-percent less power than he needed. Switching to the 700-amp Dynasty TIG welder actually reduced the draw down to a maximum 70 amps and allowed OMF to increase amperage (up to 500 amps) and switch to a smaller filler rod (1/8-in.)
“As far as inches per minute (IPM) of weld,” claims Orchard, “we probably went up a minimum of 20 percent.”
Switching to an inverter with advanced AC TIG controls also gave OMF the power to fine tune the weld profile and appearance to its application. Independent AC amperage control allows OMF to set the electrode negative (EN) and electrode positive (EP) amperage values independently. More current in EN than in EP produces deeper penetration and faster travel speeds with minimal cleaning action and less heat on the tungsten. This results in less tungsten and narrower bead profiles. AC frequency control further allows OMF to focus the bead and increase travel speeds by increasing frequency.
“It was startling how much power this thing has for bead penetration,” says Orchard. “We have to be careful not to burn through on some thick materials.”
“I describe it like this: you’re getting on the freeway and you’ve got a little Toyota Tercel with 110 horsepower. Well, ultimately, you’re only going to go 60 or 70 mph, but if you get on the freeway with a Corvette you’re going to get there as fast as you want. With the other underpowered car, you’re going to get there when it’s ready to get you there. This thing is a Corvette.”
Inverters save space, power
Especially in southern California, where expanding industrial operations is difficult, extra space and resources are at a minimum. In addition to the increases in production, OMF has seen a reduction in its power bills and has been able to set aside two separate work areas: one for MIG and one for TIG. Previously, the shop had been limited to one work area for welding, and that space was taken up by a much larger, less-mobile transformer-based welder. In addition to the TIG inverter’s power savings (70 versus 110 amps), the pulsed MIG unit only draws 34 amps when welding.
“We rent space, we don’t own. Every square foot costs X dollars,” explains Orchard. “Also, we have to deal with the electricity that is in these buildings. Bringing in more electricity is out of the question because we rent, we don’t own, the shop. So, we just can’t afford to spend a lot of money. With our other machines, at one point when we were in heavy production (7-8 welders at a time), we rented a whole extra building just to get the electricity. When we started going with the inverter machines, we didn’t have that problem. I would say, conservatively, we’re seeing 25-30 percent less power draw.”
Going off-road, keeping business in-line
Tim Orchard speaks passionately about his racing days and his involvement with the off-road racing community, but he takes just as much pride in his off-the-track accomplishments off the track as he does with his racing success. With OMF Performance Products, he has engineered high-performance off-road wheel assemblies that enjoy an impeccable reputation in the racing community, and he has found ways to improve quality and productivity while also reducing costs. That’s like lapping the competition on the racetrack, and Orchard loves every minute of it.
“I’m 54 years old, and it’s looking to me like I can probably make it to retirement without ever having to work for a living.”