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It’s Miller Time

When expansion required more welding machines, a ventilation manufacturer took it as an opportunity to “clear the air” and go with a new provider

What began as a small sheet metal shop in Schofield, WI, met success in the air-moving market. As it grew, it found the right welding solution to meet its ever-increasing needs.

It’s been almost 60 years since Bernie and Bob Greenheck first opened the doors of their shop. Today, the Greenheck Fan Co. has grown to be a leading manufacturer of commercial and institutional ventilation equipment, with sales in excess of $350 million per year.

Greenheck offers a comprehensive line of ventilation products: fans and ventilators, centrifugal and vane axial fans, kitchen ventilation systems, dampers, louvers, make-up air units, energy recovery ventilators, and laboratory exhaust systems. Its air movement and control equipment is used in commercial, institutional, and industrial buildings.

Company-wide, 180 welding operators help maintain Greenheck’s standards and quick turnaround times. Products not in stock can be built to customer specifications in one-, three-, five-, and 10-day cycles. Regardless of prior welding experience, each welding operator goes through Greenheck’s welding training program; the best then teach others.

A Need to Keep Up With the Times

Recently, Greenheck needed to add more equipment to its aluminum louver line to keep up with expansion. Rather than add more of the same welding equipment, Josh Holtz, senior manufacturing engineer, asked if technology advances held additional benefits and solutions to problems the company had with its current equipment.

Greenheck’s louvers use aluminum alloys 5052 – magnesium alloy – and 6063 –magnesium-silicon alloy – ranging in thickness from 0.080" to 750", the majority being 0.080" to 0.125". Because the products are visible, the welds – T-joints, edge, butt, and lap joints – need to be strong and look appealing.

“Our experience with the older technology welding equipment showed they’re geared to run thicker materials,” Holtz said. “They weld thicker aluminum, such as 3/16" to 1/4" material well, but we had problems once we got to the hundred-thousandths and thinner. Most of the louver line welds need to be just 1/8" wide. That was tough. Instead, we were welding 3/16" fillets. Sometimes they would get even larger due to the joint style and welding position. That not only wasted metal, but increased chances of burn-through or blistering.”

Aluminum presents welding challenges. It conducts heat about six times faster than steel, requiring higher amperages and faster wire feed speeds. It also has a relatively low melting point – 1,220 °F. These factors make thinner aluminum susceptible to burn-through.

If a weld requires rework, the welding operator is responsible for resolving the problem and ensuring that the weld meets Greenheck’s strict workmanship standards. This may involve wire brushing, crater fill-in, or resolving burn-through issues – all of which take time away from welding.

This extra time, as well as the extra filler metal used from making larger-than-necessary welds, added costs to the product – costs that had become an accepted part of the process. When Greenheck had to add more welding units to increase capacity, it found that technology developments let the company cut these hidden costs.

Older, or less-than-optimal, equipment may cut profits. Greenheck discovered this when, while adding equipment to increase capacity, it found that developments in pulsed MIG technology, specifically the Millermatic 350P pulsed MIG welder, from Miller Electric Manufacturing Co., Appleton, WI, saved it time and money.

“We wanted to add the best machine we could find,” Holtz said. “As a rule, when purchasing welding equipment, we look at three main factors: performance, cost, and reliability.”

“In this case, we were looking for a welding system that could weld thin aluminum well, yield welds that were cosmetically appealing, and was dependable and versatile. We asked Miller if they had a technology that would fit the product line.”

Miller brought a Millermatic 350P for them to try.

“We compared it to the other units on light aluminum,” Holtz said. “It offered much better performance on the material thickness we run. Its revised pulse program let us weld thin aluminum more effectively. Its arc control characteristics make it user friendly and flexible.”

Greenheck purchased 12 of the 350Ps, moving the other power sources to other operations where material thickness wasn’t critical. About 40 operators, working in three shifts, now use the machines.

“We found the 350Ps’ refined pulsed arc let us control the amount of penetration and weld size,” Holtz said. “With the better arc control, we can keep the weld size small and the louvers are more cosmetically appealing. Now we can hit weld size where before we couldn’t.”

A Better Machine for All Over Savings

Miller recently updated the Millermatic 350Ps’ programming for reduced weld spatter, increased deposition rates and deposition efficiency, and enhanced weld bead appearance. The pulsed MIG technology the machine incorporates makes it suited for Greenheck’s aluminum louver line.

The machine can weld material from 22 gauge to 1/2" in a single pass. It can run on single- or three-phase input power and offers a duty-cycle rating of 60 percent at 300 amps/32 volts, a 25- to 400-amp output and line voltage compensation. There is no de-rating when run on single-phase power.

Holtz said he likes the machine’s all-in-one design: “The 350P puts a complete package into a very mobile unit. We don’t have to purchase a separate power source and feeder.”

Besides better welding, less rework, and consumable savings, Greenheck saved 38 percent per machine purchased. With a 10 percent reduction in rework, the company saves $4,160 per year.

Adding to those savings is a 25 percent reduction in filler metal. For instance, a 25 percent reduction in filler metal for a company using 1,000 lb of 0.047" 4043 filler wire per month, at an average cost of $3.35 per pound, saves $837 per month, about $10,000 per year.

One of the machine’s non-monetary benefits is its interface. To begin pulsed MIG with the 350P, the operator selects the built-in program that matches the wire type and size, and the unit sets the pulse parameters. Once the desired arc length is set, the operator adjusts wire feed speed to weld a different thickness of metal.

The technology built in to the units lets it rival TIG weld appearance. A good-looking weld is important to Greenheck.

With the 350Ps onboard, meeting specifications is easier and more efficient. It’s just part of Greenheck’s ongoing commitment to quality and its customers.

“We try to be the easiest company with which to do business as well as make a quality product,” Holtz said. “Those are the things that let us grow.”

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Miller Electric Mfg. Co.