September/October 2010
Stationary shears process high-quality ferrous metals more efficiently and at a lower cost than their flashier scrapyard kin, the automobile shredder. It’s all about using the right tool for the material and the market, shear sellers say.
By Ann C. Logue
Chop, chop, chop. That’s what a stationary shear does: It cleaves huge pieces of structural steel into smaller pieces that a scrapyard can sell to a steel mill or foundry. It’s designed to handle bulky items such as pipes, containers, or railcars, as well as stringy, tangled ferrous metal, such as rebar, which it compresses and chops into more manageable pieces. When used with the right type and volume of material, it can process metal better and more efficiently than any other piece of scrapyard equipment, manufacturers say. These machines have been reliable workhorses of the scrap industry for decades, with incremental improvements in design over the years. They admittedly don’t have the same “wow” factor as a shredder, but the two machines are like apples and oranges, sellers and users say, because they’re designed for different material streams. The secret of stationary shear success is knowing when it’s the right tool for a company’s material and markets and then maintaining it to ensure many years of reliable service.
Design Basics
Stationary shear prices start at just under a million dollars and run as high as $7 million, depending on the size and the features, plus ongoing maintenance and power expenses. In the most prevalent design, scrapyard workers use a grapple or magnet to feed the scrap into a flat precompression, or sizing, box that squeezes the material into a compact bundle and pushes it into the path of the falling shear blade, which cuts the heavy ferrous metal down to a manageable size.
The precompression chambers come in variations of two basic designs. The “side-compression” design that European manufacturers most commonly use compresses the material from the sides and the top. The “tuck-and-fold” design, in contrast, has arms on one or both sides of the chamber that support trough-like plates the length of the chamber. When the chamber is open, the trough is parallel to the ground, and the operator can place scrap in it or in the chamber. The arm lifts and pivots the plate over the scrap, pushing it into the chamber. The second arm pivots over the chamber as well, overlapping the first plate to push the scrap from the opposite side, like it’s making a folded scrap omelet. Models with just one moving arm push the scrap against a rigid chamber wall and floor. The tuck-and-fold design excels at compressing large, bulky pieces, such as tanks, one company representative says, whereas the side-compression design offers the greatest overall compression strength, which “more effectively breaks down structural material such as truck frames.” Some manufacturers offer both designs.
The precompression chamber’s ability to handle large, bulky material is a key factor in productivity, sellers explain, because it can eliminate the need to torchcut items into smaller pieces to prepare them for shearing. Another variable is precompression chamber size. Most manufacturers offer standard chamber sizes and the option of custom sizes. Whether a custom chamber is worth the expense depends on the scrap supply, one representative says. If a yard knows it will have a steady supply of something especially lengthy to shear, like end-of-life gondola railcars, it might want a larger chamber to minimize the need for torchcutting.
An alternative infeed design, first introduced to the market by Vezzani (Ovada, Italy) but now offered by additional manufacturers, uses an inclined, gravity-fed input system. Gravity-feed shears use less energy than flat-feed models, these manufacturers say, and they are easier to maintain because they have fewer moving parts. Some gravity-feed models also use compression to aid the flow of material under the shear blade. This design is well-suited for long products such as pipes and I-beams, but it typically offers less side-compression force and has nothing pushing the material into the blade, giving it less versatility and less feed precision than shears with a flat precompression chamber, say manufacturers of competing designs.
Today’s shears cut and cycle faster and have better hydraulic systems than shears sold even a few years ago, manufacturers say. Such improvements can translate to better productivity, but that’s rarely the case in actual use because few yards operate their shears at maximum capacity. “It’s rare that a faster shear automatically results in more production,” one company executive says. There’s some disagreement over the value of greater hydraulic pressure. Machines generating 5,000 psi are on the market, though 3,000 psi is more common. Some manufacturers say the greater pressure is more efficient and creates more force; others insist the higher pressure just results in more leaks.
Cutting forces have held relatively steady over the years, maxing out around 2,000 to 2,200 tons of force, though shears that powerful are rare. The 2,000-ton shears can cut 5-inch or 6-inch steel plate, which is more than even the biggest shredder can do. Instead, one company representative says he has seen more growth in the market at the bottom end of the scale. “People didn’t buy 600- to 800-ton shears for a long time,” he says, instead preferring those that offer around 1,000 tons of cutting force. Though 1,000-ton to 1,600-ton shears are still the most popular in North America, “smaller shears are making a comeback,” he says. Another company representative confirms that “small shears still have their place in the market.” The heavier the cutting force, the heavier and thicker the material the shear can cut.
Certain shear models offer variable speeds to change the length of the sheared material, which might provide some advantages in sorting or in marketing. To get the right size cut, operators adjust the compression for the material feed that goes to the blade as well as the speed at which the blade chops. Greater compression and a faster cutting speed will create smaller pieces of scrap. Many of the shears also collect data on speed, load sizes, and other production statistics that yards can use to analyze operating efficiency.
The processing capacity for state-of-the-art shears ranges from 10 mt to 50 mt an hour, depending on design. Larger shear heads and greater pressure result in greater capacity because they cut more steel in less time. Though some models offer continuous operations, the value of such a feature depends on whether the yard has the volume of material to make use of it.
Selecting the right shear for a specific yard is a matter of finding the sweet spot between too large and too small. A high-volume machine that gives a yard excess capacity might waste energy and yard space; a low-volume machine might not be able to keep up with the supply of material. To pick the right shear size and capacity, a buyer needs to consider how much and what type of material the yard has, what else it can reasonably obtain, and what material its customers need. Too small is a bigger problem than too large; accordingly, buyers tend to pick larger shears over smaller ones, shear sellers say.
Shear Safety
There’s no question that stationary shears are potentially dangerous. Shears have sharp blades and moving parts that can kill a worker who’s in the wrong place at the wrong time. Incremental improvements in technology and new safety features reduce some of the danger, though “I haven’t seen any big changes in technology when it comes to safety,” one source says. Newer machines—those made in the past decade or so—offer safety features such as stop buttons, auto-stop sensors that detect excessively high hydraulic pressure or jams in the compression box, cover plates, and noise-reducing designs.
One advancement, the ability for the shear operator to remotely control the crane feeding the shear, could actually create safety concerns, notes one company representative. “For that to work well, you need a really organized setup, with another crane setting [material] in place” and the remote crane simply feeding the shear, he says. “You can’t have the shear operator [remotely] unloading a truck, swinging the crane all over the place,” and operating the shear at the same time. It’s unsafe and probably less efficient, he says.
The shear’s safety features might be useless if workers don’t operate the equipment correctly, of course. Most manufacturers offer safety and operation training programs. Because of the shears’ long lifespans, some also offer retraining programs to ensure that new employees can use the old equipment according to modern standards. In fact, the various shear manufacturers try to distinguish themselves by the services they provide to go with the machines. Many buyers want expert advice from factory technicians to ensure that their investment is both profitable and safe.
At the time of installation, the shear manufacturer’s representative should make sure that everyone in the yard knows what the safe and unsafe areas of the machine are and label those hot spots accordingly. Even if the yard has had previous shears, a new device will have different features—and different danger zones—than the old one.
Stationary shear manufacturers should continue to improve shear design, control features, installation, and training to make the shears as safe as possible, says John Gilstrap, ISRI’s director of safety. He recommends that buyers tell manufacturers their ongoing safety concerns or potential improvements. “The manufacturer can’t address safety concerns if the customer doesn’t bring them up,” he says. “The onus is on our members to hold the manufacturers’ feet to the fire.” But the shearmaker’s responsibility only goes so far: “The manufacturer can’t control what the yard puts through the shear,” Gilstrap points out. It’s the operator’s responsibility to keep the shear free of material that could explode, leak, or otherwise create hazardous conditions when crushed or cut.
Maintenance for the Long Haul
A well-maintained stationary shear can last for decades. In fact, all the manufacturers interviewed for this article say their biggest competitor is the shear already in the scrapyard. Yards usually purchase a new shear to handle greater material volumes, not because the old one doesn’t work. As a result, there is a robust market in used equipment. A yard looking to get the most from its shear investment—either for long-term use or potential resale—simply needs to stay on top of maintenance. The staff has to commit to doing the work.
Basic maintenance consists, first and foremost, of keeping the cylinders greased at all times—something that’s easy to do every morning before starting up the shear, but it sometimes gets overlooked. Users should keep the blade in alignment to ensure that the shear cuts straight down; it will wear out more quickly if it cuts on an angle. “The best blades today last longer than [blades] used to due to improved steel alloys,” one vendor says. “They can go for months, even on high-production machines.” It’s important to properly place and align the blade during replacement, too. Blade replacement can take as little as an hour to several hours, depending on equipment condition. Other ongoing maintenance includes rebuilding floors, replacing seats in the cab, and upgrading the electrical wiring, similar to the work any heavy equipment might require. “Most operations now use a planned maintenance program using factory technicians once or twice a year,” notes one company representative.
The Right Tool for the Job
Automobile shredders are so powerful that yard managers sometimes think they’re good substitutes for stationary shears. That’s just not true, say those consulted for this story—including those whose companies sell both shredders and shears. Each major piece of scrapyard equipment has its own purpose. “Shred shreddables, shear shearables, [and] bale baleables,” is how one source put it. Ultimately, a yard’s material stream and the needs of its consumers will dictate what equipment it should purchase.
The type of material the yard receives is one important factor. Shredders are ideal for processing mixed ferrous and nonferrous materials, such as appliances and cars, that have to be size-reduced and separated into specific commodities for sale. They “will make low-quality scrap into high-quality scrap and separate waste from higher-value nonferrous materials,” one source says. “No other machine does that.” Shears, in contrast, are designed for material of uniform composition that only needs to be compressed and cut down to size. They do less, but they do it more efficiently. “Yes, you can put I-beams in a shredder, but there is no benefit to it,” one sales representative says.
Operating cost and material value are also factors in selecting which tool to use. Shredders are much more expensive to operate, which would seem to give shears the edge for high-value ferrous material. As one vendor puts it, “Why spend $40 a ton to shred something you can cut for perhaps $10 a ton?” Even if shredded steel and No. 1 heavy melting steel are selling for the same price, it costs less per ton to cut it than to shred it. That said, once a shredder is running, the yard has an incentive to keep it fed—it’s incurring expenses whether it’s processing material or not. In some cases it could make sense to shred No. 1 steel instead of shearing it, this source admits, such as if the yard doesn’t have enough No. 1 steel to meet the customer’s minimum order requirement. At the same time, “some material, by the nature of its size and structural makeup, cannot be processed in a shredder,” one rep says.
Even with some overlap in function, stationary shears are not really competing with shredders in the scrapyard. Instead, sellers say, their competition is coming from the low end—from lightweight, mobile shears and shear attachments. The largest of these shears might offer the same cutting force as a stationary shear, but they can handle only a fraction of the processing capacity of a stationary shear, manufacturers say. They don’t seem too concerned about this competition, noting that most yards need equipment with overlapping capabilities unless they are willing to ship material for processing elsewhere.
Purchasing Outlook
For many stationary shear buyers, metal prices—specifically, steel prices—drive the purchasing decision more than the overall economy does. Metal prices affect both the volume of material arriving in the yard and the yard’s profitability, thus its ability to invest in new equipment. Sales reps report that some buyers may be delaying a purchase until steel prices rise, but demand for their products remains steady, despite the recession. Scrap continues to flow into yards and require processing, after all.
Despite the recent credit crunch, shear sellers say financing is not an issue, either. Banks and finance companies are willing to write loans, arrange leases, and otherwise use creative approaches to help qualified yards buy the equipment they need. Interest rates are lower than usual, too, which can reduce the total cost of ownership.
One economic factor that has affected shear sales is currency fluctuation. For the shear brands manufactured in Europe, the strength of the dollar against the euro can affect the price of their shears. They have had weak North American sales in recent years, they say, because of the strong euro, which made their equipment relatively more expensive. This year started off with a serious economic crisis in the European Union, however, which made the euro cheaper relative to the dollar and made those shear prices more competitive with their domestic counterparts.
Shear manufacturers speak highly of the quality of equipment throughout this market segment, regardless of brand. The differences, they say, are in price, service, and features, with each customer determining the most important factors for its yard. All agree that a wise stationary shear purchase can help a yard build profits. “Good equipment will make you more money in the long run because it will keep your processing costs low,” one contact says. “Efficiency will keep you competitive.”
Ann C. Logue is a Chicago-based writer.
Stationary shears process high-quality ferrous metals more efficiently and at a lower cost than their flashier scrapyard kin, the automobile shredder. It’s all about using the right tool for the material and the market, shear sellers say.