This industry encompasses companies primarily engaged in manufacturing sheet metal work for buildings (not including fabrication work done by construction contractors at the place of construction) as well as stovepipes, light tanks, and other products of sheet metal.
332322 (Sheet Metal Work Manufacturing)
In the late 1990s, 4,201 companies were involved in the U.S. sheet metal work industry. They employed 142,682 workers and generated $19.3 billion in shipments in 2000. California, Ohio, Illinois, and Texas accounted for more than 33 percent of the industry's total shipments. The most common end uses for sheet metal in the late 1990s were electronic enclosures (such as personal computer housings or casings, accounting for 21.8 percent of end uses); roofing and roof drainage equipment (8.7 percent); air conditioning ducts and stove pipes (10.3 percent); sheet metal flooring and siding (7.6 percent); awnings, canopies, cornices, and soffits (4.2 percent); culverts, flumes, irrigation pipes (2.9 percent); and other or unspecified uses (44.5 percent). These categories cover a myriad of products used by every industry from aircraft manufacture (air cowls), building construction (siding, stove hoods, and gutters), heating, ventilation, and air conditioning (HVAC) applications (ducts, furnace flues), mineral processing (coal chutes), and highway construction (guardrails) to agriculture (irrigation pipes), business machines (computer casings, shipbuilding (ship ventilators), postal delivery (mail boxes), and food preparation (vats and bins).
Sheet metal forming is one of the most basic and pervasive manufacturing processes in U.S. industry. In general, sheet metal products manufactured by industry firms have thin walls, simple as well as complex designs, and a large quantity of surface area in relation to thickness. They are generally lighter in weight and more versatile than metal products formed and shaped through casting and forging processes. The manufacture of sheet metal products is generally characterized by low to moderate costs for labor, equipment, and dies.
Industry sheet metal products are manufactured with a wide range of metal-forming machine tools. Several different techniques can be used to produce the same sheet metal part. The factors determining which method to use include the cost of the die, the amount of labor available, the number of sheet metal parts to be made, and the speed of production. Deep-drawing methods, for example, involve more complicated machinery and cost more than other methods, but they are also faster and more cost effective for jobs involving the manufacture of many parts.
In 1997, the sheet metal industry consumed 45 percent the value of its total shipments on materials and supplies, primarily from blast furnaces and steel mills and aluminum rolling and drawing companies. Low-carbon steel was the most widely used metal for sheet metal processes because of its low cost and high strength and formability.
Throughout the late 1990s, the sheet metal industry experienced steady, uninterrupted growth. The value of shipments jumped from $15.5 billion in 1997 to $19.3 billion in 2000. In the same period, total industry employment rose from 127,791 workers to 142,682 workers.
In the late 1990s, sheet metal work remained a strong market, fueled by the booming American economy. HVAC systems and business/computer machines were the two largest buyers of the sheet metal work industry's products, and demand for HVAC systems and computer goods remained high at the end of the century. Moreover, when the economy weakened in 2000, falling interest rates bolstered new home and building construction, which in turn fostered demand for many sheet metal work products for roofing and siding. Demand for steel sheet metal work was especially robust, and a slew of companies strove to fill consumers' needs. The supply of steel sheet metal rose in the late 1990s and early 2000s as cheaper imported steel flooded the U.S. market. At the same time, U.S. production capacity expanded as a result of a new generation of new steel "mini-mills." Both these factors kept steel prices low, according to The Value Line Investment Survey . Although domestic steel producers suffered, sheet metal work industry firms benefited from the low prices of steel sheet metal needed for their work. Because of the importance of HVAC systems and business/computer machines to the U.S. economy, these two largest buyers of the sheet metal work industry's products seemed to offer the greatest opportunity for future industry growth.
The leading U.S. sheet metal work firms in 1995 were Consolidated Systems Inc. of South Carolina ($160 million in sales, with 400 workers), Alcan Building Products of Ohio ($120 million, 1,200 employees), Bouras Industries Inc. of New Jersey ($110 million, 500), Harrow Corporation of Michigan ($110 million, 1,200), and Hart and Cooley Inc. of Michigan ($100 million, 1,200). Other leading firms included Syro Steel, Symons Corporation, ASC Pacific Inc., and Coastline Distribution Inc.
In 1995, Consolidated Systems announced it was constructing a manufacturing plant and warehouse in Jackson, Mississippi, and the same year Alcan Building Products—a major manufacturer of canopies, awnings, and other exterior building products—was bought out by its management and renamed Alument Building Products. In 1996, Harsco Corporation announced that it had acquired Symons Corporation, a maker of prefabricated concrete forming equipment, and Watsco Inc. purchased Coastline Distribution, a maker of HVAC-related products.
In the late 1990s, the vast majority of the nation's sheet metal workers toiled for firms outside the sheet metal industry, such as on-site construction contractors, for example, or in the plumbing and HVAC business. In 2000, the sheet metal industry's 107,7898 production workers, however, represented an important segment of the American sheet metal work force, and were represented in part by the Sheet Metal Workers' International Association (SMWIA). That union, formed in Toledo, Ohio, in 1888, claimed 134,000 members and 205 local unions in the mid-1990s. In 1996 in Milwaukee, the SMWIA Local 18 experimented with a novel way to ensure job security by offering consumers rebates if they bought furnaces or central air conditioning systems from union contractors. Sheet metal workers often learned the trade through apprenticeships involving four to five years of combined classroom and on-the-job training. The average production worker in the sheet metal work industry in 2000 earned $14.54 an hour.
Technological advances in the sheet metal work industry in 1990s were revolutionizing the efficiency and precision with which sheet metal products were fabricated. These advances centered in large part on improving tools, dies, and other equipment; relying more extensively on automated machinery; and embracing the benefits of the computer, new software, and—for marketing purposes—the World Wide Web.
A new turret punch press introduced in the 1990s allowed machine tool operators in the sheet metal industry to punch, cut, separate, and sort finished metal blanks in a single operation rather than the three-part operation previously required. The machine's 21 hole-punching tools could be adjusted to perform simple unsupervised operations or more complicated processes involving automatic retrieval and storage of parts. Even more impressive was the Trumatic 2000 Rotation compact punching and forming machine, which was introduced in 1998 by the German tool manufacturer, Trumpf GmbH & Co. The Trumatic 2000 could punch up 900 hits per minute, and could make prototypes as well as medium production runs. Similarly, electromechanically operated industrial robots were used extensively to accurately and tirelessly perform the continuous machining motions once performed by humans.
Although Japanese and European firms led U.S. manufacturers in the use of laser-cutting technology for cutting sheet metal to product specifications in the early 1990s, the United States gained ground on its foreign competitors in this crucial manufacturing technology as the decade progressed. In the mid-1990s, an Ohio State engineering professor began experimenting with the use of lasers and light-emitting diodes (LEDs) to detect the wrinkles that develop when the pressure exerted by a die is inappropriately calibrated to the strength of the sheet metal being pushed into it. By detecting wrinkles instantaneously, just as they begin to occur, the sensors enabled a computer to automatically re-adjust the pressure on the metal before the wrinkles marred the sheet. A laser application, developed in the mid-1990s for sheet metal work in the aerospace industry, combined the precision and automation of laser technology for finishing and trimming metal parts with the design and efficiency benefits of CAD/CAM (computeraided design/computer-aided manufacture) software to reduce project lead time by two-thirds and costs by up to a quarter. In 1998, Rofin-Sinar and the Frauenhofer Institute of Germany debuted a multi-kilowatt diode-pumped Nd: YAG laser for industrial processing.
In response to the need to cut costs and increase equipment durability, some industry firms turned to plastics, epoxy, and polyurethane in the 1990s to replace more traditional metallic tools and dies. Software programs using finite element analysis (FEA) also enabled product designers to predict the effectiveness of sheet metal stamping dies for the manufacture of products with intricate surfaces, and identified potential strains and stresses in the metal. FEA also enabled manufacturers to accurately predict potential problems in sheet metal bending operations before any metal was actually machined. Software packages such as "PE/Sheet Advisor" used a combination of "expert system" logic and three-dimensional modeling to enable sheet metal product manufacturers to incorporate data gathered from manufacturing operations into the design of new products.
Large sheet metal operations used central computers to direct all sheet metal-forming operations. This "systems approach" managed entire sheet metal processes using vast unified databases containing information on materials, tool and die parameters, and the mechanical properties of the variables of the sheet metal manufacturing process. The efficiency of such CAD/CAM programs as AutoCAD (the industry standard) was estimated to be four to five times greater than traditional methods. Small- to medium-sized firms—which were generally unable to afford the costs of a truly integrated and centralized sheet metal CAM system—could purchase simulation or modeling CAD software to eliminate the costly trial-and-error methods for developing and manufacturing new products. "MetalMan," a Windows-based software program designing sheet metal parts, used a graphic user interface that simulated a machine shop, enabling designers to form three-dimensional solid models of the parts they wished to fabricate, exchange data with other CAD programs, and add to and evaluate new operations in the fabrication process. Such programs could also produce cost quotes and estimates, maintain manufacturing schedules, keep inventories, and generate specification reports for each part.
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