July/August 2011
Technological advances have given this equipment more cutting power in a smaller, lighter package, making it the tool of choice for scrapyards with bulky scrap made from a variety of metals.
By Ken McEntee
Scrap processing was once a simpler business than it is today. Large, bulky scrap items were nearly always ferrous metal, and yard workers could cut them with oxy-fuel torches into smaller, manageable pieces they could ship to their customers. Over the years, the need for cutting scrap down to size has not changed. “Freight is prohibitively expensive, so you have to get the most material on the load that you can, and size reduction is one of the ways you can do that,” says Mark Lotzkar, president and general manager of Pacific Metals Recycling International (Vancouver, British Columbia). “You also have to appreciate that, when you send a scrap metal product to a customer, that specification includes size. If that load is not sized correctly, you lose money.”
What has changed is the composition of the scrap. Today, bulky items could be “aluminum, stainless steel, nickel, and a lot of exotic metals,” says a sales rep for one equipment vendor. “It’s changed the way scrapyards do their cutting” because oxy-fuel torches can cut only ferrous. Scrapyards faced with this variety of metals are turning to hand-held plasma cutters. A plasma cutter “can cut anything that conducts electricity,” says a product manager for another manufacturer. A hand-held plasma cutter is “the best cutting device available when you’re working with a wide range of materials, especially when you’re not concerned with getting a very precise cut,” which is the case for scrap operations.
How It Works
The technology involved in plasma cutting is surprisingly simple, says the welding equipment product manager at a company that makes an array of cutting and welding products. All it takes is an electrical power source, compressed air or gas (such as argon or nitrogen), and a specialized cutting torch. The power source delivers amperage to the torch nozzle, heating a flow of compressed air or gas to temperatures that exceed 18,000 degrees F—about twice the temperature of the flame of an oxy-fuel torch. The combination creates a superheated flow of plasma, which the product manager describes as “a gas-like state of matter with ionized particles.” The plasma transfers an electrical arc to the work piece, creating a clean, dross-free cut. It melts through metal like a hot knife through butter, as the saying goes. Portable plasma cutters draw amperages that range from 15 to 400, which can cut metals up to 2 inches thick. Input power can range from 115 to 440 volts.
The product manager points out several differences between oxy-fuel and plasma cutting. “When you cut with [an] oxy-fuel [torch], you are depending on the chemical reaction between pure oxygen and the iron—it is an oxidation process. With plasma, you are actually melting through the metal.” Not only is plasma more versatile, it’s also more efficient, he adds. “With oxy-fuel cutting, you’re just holding the torch [in front of the material you’re cutting] until the material gets hot enough. Plasma delivers a peak temperature instantaneously” and does not require pre-heating.
Plasma cutting technology has been around since the late 1950s, but it took the scrap industry until the 1990s to begin adopting it on a widespread basis. Technological advances and practical considerations were the main drivers. Plasma cutting machines have become more portable, thanks mainly to electrical inverter technology that allows a small machine to pump out a lot of power, these representatives explain. Back in the 1980s, a plasma cutter that could tackle half-inch-thick metal weighed 700 pounds, says the sales rep. Now companies offer that power in machines that weigh less than 50 pounds. “The reduction in size was made possible by the inverter technology.” Further, manufacturers developed the ability to generate plasma from compressed air instead of gas. “When the technology was first developed, gases like carbon dioxide and nitrogen were required,” he says. “Air plasmas made the machines very simple to use.” Prices have gone down as well. “The price per amp is about half what you paid in 1990,” says a plasma automation specialist. Portable machines begin in the $700 to $3,000 price range. And the ability to use compressed air means there’s no need to buy gas cylinders—and one less potential hazard in the yard.
Manufacturers typically rate their plasma cutters on amperage, the product manager says, but amperage does not provide an apples-to-apples comparison of a machine’s capability. “A lot depends on how a manufacturer is able to deliver that input amperage to the cutting arc,” he explains. “The bottom line is, how many kilowatts are available in the arc? That can depend on a number of variables, like the design of the nozzle.” The best way to tell whether a machine will suit your application, he says, is to watch it in action. “We can put video right on our website so people can get an idea of what the machines can do.”
Scrapyard Experiences
Dan Becker, vice president and co-owner of Becker Iron & Metal (St. Louis), recalls first seeing another local yard use a hand-held plasma cutter to size stainless steel and nickel alloys about seven years ago. “It was faster and cheaper than using propane [torches] and cutoff saws,” he says. The up-front costs were higher compared with an oxy-fuel torch, but “we figured it would be a lot quicker for our nonferrous operation.”
The company, which processes ferrous and nonferrous metals for direct shipment to mills and foundries, opted to purchase its first plasma cutter, and General Manager Wayne Lindberg says he immediately noted the savings. “We used it for stainless and aluminum,” he says. “It saved us on time and cost.” Stainless steel processing is probably where the biggest time savings are, he says. “If you use the cutoff saw on aluminum, it goes through pretty quickly, but stainless is a different animal,” Lindberg says. “It’s a harder material, but the plasma just cuts right through it.” And in terms of cost, “you don’t have fuel to pay for. All you need is a good compressor and electricity.”
As the company’s volume of materials increased it saw the need for a second plasma cutter, so three or four years ago it purchased a model that was “beefier and could cut even thicker” metal, Becker says—steel up to 7/8 inch thick and stainless and aluminum up to ¾ inch. “So now we have both of them, and we use them both at the same time. It has been a great deal.” The purchases were “a no-brainer,” he says. “Without the plasma cutters, we would be a lot slower in processing our materials. That means we would be a lot slower at shipping out our product.”
Despite the higher up-front cost compared with an oxy-fuel torch, the payback on a plasma cutter does not take long, Becker adds. “You might spend $2,000 to $4,000 on a plasma system,” whereas a cutting torch might be less than $1,000, “but you make the costs up quickly. You save on labor costs because you can process things faster. It’s not only the speed of processing that you have to think about, but also the downtime. You don’t have to change out fuel cylinders. All you do is plug and play.”
In Vancouver, Pacific Metals has used a plasma cutter for 20 years. “We primarily use it to [upgrade] scrap that is of more than one alloy or may need a contaminant to be removed,” Lotzkar says, as well as to size materials too big to go into the company’s two balers. “The plasma allows us to reduce the size very quickly and also to make sure that [the material] is clean, to maintain the quality. We use it primarily for aluminum and stainless, but sometimes for ferrous.” He also touts the plasma cutter’s speed, light weight, and ease of use. “With a steady hand, as fast as you can draw your hand over the work item,” you can cut it. “It’s very quick.”
Recent Innovations
Manufacturers continue to make advances in these tools’ power, portability, and durability to improve their efficiency and reduce their operating cost, the product manager says. His company launched a new family of plasma cutters in February, with two models priced at less than $2,000. One of those two has an internal air compressor, so “all you have to do is plug it into the wall and start cutting,” he says. The line also features improved torch technology that reduces operating costs, he says.
His company wants to stand out for its products’ portability and ease of use, the product manager says. “To compete with the portability of oxy-fuel [torches], we have tried to make our products smaller and more powerful.” For example, the company took its 60-amp unit, “which is our largest system, and put it in a 52-pound box for easy mobility. You just need to have power available to you—either wall power or a generator.” That product will cut metal ½ inch to 7/8 inch thick, whereas a smaller machine, which pulls 40 amps and weighs 21 pounds, will cut metal 5/8 inch thick, he says. That unit works well in tandem with the company’s air pack—a welder generator with a built-in air compressor. “It isn’t a plasma machine,” the product manager explains. “It’s a box with a generator and a welding tip, and now we have added a compressor that provides up to 1,160 pounds [of pressure] per square inch. There is a wide variety of things you can hook up to it, and a plasma cutter is one of them.”
In terms of ease of use, the company realizes, he says, that “some people may not be using the machine on a daily basis, so we have taken away a lot of knobs and buttons and made a lot of the functions automatic, so when you pull it off the shelf you can plug it in and go.” For example, the machine “is smart enough to set its own air pressure to give the torch exactly what it needs.” Also, “if you’re cutting expanded metal with gaps,” he says, “a common problem is that the arc goes off when you get to a gap. We’ve made it an automatic refire, so you don’t have to walk back to the box and push a button to make it go back on, [something] that’s especially annoying if you’re working 50 feet away from the box.”
Another company launched a new product in March, a 26-pound unit that can cut steel up to 5/8 inch thick with input power of 115 or 230 volts. This “new, smaller torch” is “very light, which is suitable for use on sheet metal or in places where the only power available is 110 volts,” says the plasma automation specialist. The company makes four other models in this line, with power levels between 60 and 120 amps. The product with 60 amps can cut through metal that’s ½ inch to 5/8 inch thick. In his experience, the sales rep says, scrapyards “are buying plasma cutters between 120 and 200 amps, which gives them a wide range to cut. … A 120-amp system will cut an inch and a quarter. A 200-amp [system] will allow them to cut 1½ to 1¾ inches.” That should be sufficient for most scrapyards, but the company also offers a line that ranges up to 400 amps “designed for heavy-duty work up in the 2-inch world,” says the plasma automation specialist. “What the scrapyards want is low cost, high flexibility, and ease of use,” he explains. “At 120 amps, when you get into the thicker stainless and aluminum, that isn’t enough.” The bigger machines require gases other than compressed air, however.
A third company—one that has specialized in plasma products for more than 40 years—says it has improved its products’ durability. “We talked to the customers in extreme environments, including scrapyards, and learned that durability is a big issue for them,” says the company’s public relations manager. “When you go into the yards, you see how these machines are treated. They are thrown around and dropped and who knows what else, so we designed [these] torches to be five times more impact-resistant and five times more heat-resistant than our previous torches.” The company introduced the new torch last fall, along with two new plasma systems and a retrofit so owners of the company’s older plasma systems can use the new torch. The company also has several patented technologies that expand the life of the torch’s consumable parts, she adds.
Use and Maintenance
Training for plasma cutting is simple, the company representatives say. “You can teach a novice to use a plasma cutter in a couple of minutes,” says the plasma automation specialist. (He proves it by turning a plasma torch over to this unskilled writer—without incident—at the recent ConExpo equipment show in Las Vegas.) “With 15 to 20 minutes of instruction, somebody can cut safely. You can’t do that with oxy-fuel [torches].” Lotzkar agrees. “The learning curve is nowhere near what you need to be a welder or a burner,” he says. “You just need to understand that you are using electrical equipment. As with any other equipment, make sure your employee understands that he needs to handle it with care. If that happens, you’re going to get good value out of your tools, and you are going to have a valuable employee who knows how to clean metal.”
Even though the units are portable, Becker uses its plasma cutters in a dedicated location on a concrete pad behind the company’s warehouse. Similarly, Pacific Metals always operates its plasma cutters on a grounded surface inside its shop, out of the potentially wet or snowy weather, which can create maintenance issues for these electric tools. “Our current system is a state-of-the-art, portable unit that we can use in a number of locations, but we choose to keep it in one place,” Lotzkar says. That way, he explains, the workers know that “everything we place on the grounded surface is ready for cutting.” Further, he points out, “the equipment is expensive,” and keeping it in a designated spot minimizes the chances of someone dropping scrap on it or driving over it.
When it comes to operating costs, plasma cutters are “very economical,” says the welding equipment product manager, because they have few moving parts. “You plug it in and go.” For Pacific Metals, “most of our money is spent on getting good, clean, dry air into the machine,” Lotzkar says. The company uses an air dryer system “that keeps the air delivered to the plasma torch dry and extremely clean,” which is what most manufacturers recommend. “If there is moisture, you can get premature failure on the consumable parts.” Other routine maintenance can include replacing worn-out handles, grips, and the cable to the handle. “We usually buy a spare handle and cable to reduce any downtime,” he says.
Those consumables are the largest routine cost of operating a plasma cutter, users and manufacturers agree. They consist of “three or four brass components in the nozzle and the zirconium tip, which has to be replaced after so many hours of use,” the product manager says about his products. Becker estimates that his company spends less than $1,000 a year in replacement parts for its plasma cutters. That’s “nothing compared to what you pay to maintain [an oxy-fuel torch],” he says. According to Lotzkar, “if properly used, the consumable parts are a negligible part of operation. If improperly used, then it can be sort of a burden. It can get pricey if your worker isn’t using the machine right” and handling it with the care required of any scrap processing equipment.
One good thing about the parts, he adds, is that “when you’re finished, they go right into the brass and copper scrap pile. They are excellent scrap.”
Ken McEntee is editor and publisher of The Paper Stock Report and Paper Recycling Online (www.recycle.cc).
Technological advances have given this equipment more cutting power in a smaller, lighter package, making it the tool of choice for scrapyards with bulky scrap made from a variety of metals.