Fabrication (metal)

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A typical steel fabrication shop

A set of six-axis welding robots. Fabrication as an industrial term refers to building metal structures by cutting, bending, and assembling. The cutting part of fabrication is via sawing, shearing, or chiseling (all with manual and powered variants); torching with handheld torches (such as oxy-fuel torches or plasma torches); and via CNC cutters (using a laser, torch, or water jet). The bending is via hammering (manual or powered) or via press brakes and similar tools. The assembling (joining of the pieces) is via welding, binding with adhesives, riveting, threaded fasteners, or even yet more bending in the form of a crimped seam. Structural steel and sheet metal are the usual starting materials for fabrication, along with the welding wire, flux, and fasteners that will join the cut pieces. As with other manufacturing processes, both human labor and automation are commonly used. The product resulting from (the process of) fabrication may be called a fabrication. Shops that specialize in this type of metal work are called fab shops. The end products of other common types of metalworking, such as machining, metal stamping, forging, and casting, may be similar in shape and function, but those processes are not classified as fabrication. Fabrication comprises or overlaps with various metalworking specialties

Fabrication shops and machine shops have overlapping capabilities, but fabrication shops generally concentrate on metal preparation and assembly as described above.

By comparison, machine shops also cut metal, but they are more concerned with the machining of parts on machine tools. Firms that encompass both fab work and machining are also common.

Blacksmithing has always involved fabrication, although it was not always called by that name. The products produced by welders, which are often referred to as weldments, are an example of fabrication. Boilermakers originally specialized in boilers, leading to their trade's name, but the term as used today has a broader meaning. Similarly, millwrights originally specialized in setting up grain mills and saw mills, but today they may be called upon for a broad range of fabrication work. Ironworkers, also known as steel erectors, also engage in fabrication. Often the fabrications for structural work begin as prefabricated segments in a fab shop, then are moved to the site by truck, rail, or barge, and finally are installed by erectors.

Contents
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1 Metal fabrication

1.1 Engineering 1.2 Raw materials 1.3 Cutting and burning 1.4 Forming 1.5 Machining 1.6 Welding 1.7 Final assembly

2 Specialities 3 See also 4 External links

[edit] Metal fabrication

Metal fabrication is a value added process that involves the construction of machines and structures from various raw materials. A fab shop will bid on a job, usually based on the engineering drawings, and if awarded the contract will build the product. Fabrication shops are employed by contractors, OEMs and VARs. Typical projects include; loose parts, structural frames for buildings and heavy equipment, and hand railings and stairs for buildings.

[edit] Engineering
The fabricator may employ or contract out steel detailers to prepare shop drawings, if not provided by the customer, which the fabricating shop will use for manufacturing. Manufacturing engineers will program CNC machines as needed.

[edit] Raw materials

Standard raw materials used by metal fabricators are;

plate metal formed and expanded metal tube stock, CDSM square stock

sectional metals (I beams, W beams, C-channel...)

welding wire hardware castings fittings

[edit] Cutting and burning

The raw material has to be cut to size. This is done with a variety of tools. The most common way to cut material is by Shearing (metalworking); Special band saws designed for cutting metal have hardened blades and a feed mechanism for even cutting. Abrasive cut-off saws, also known as chop saws, are similar to miter saws but with a steel cutting abrasive disk. Cutting torches can cut very large sections of steel with little effort. Burn tables are CNC cutting torches, usually natural gas powered. Plasma and laser cutting tables, and Water jet cutters, are also common. Plate steel is loaded on a table and the parts are cut out as programmed. The support table is made of a grid of bars that can be replaced. Some very expensive burn tables also include CNC punch capability, with a carousel of different punches and taps. Fabrication of structural steel by plasma and laser cutting introduces robots to move the cutting head in three dimensions around the material to be cut.

[edit] Forming
Hydraulic brake presses with v-dies are the most common method of forming metal. The cut plate is placed in the press and a v-shaped die is pressed a predetermined distance to bend the plate to the desired angle. Wing brakes and hand powered brakes are sometimes used. Tube bending machines have specially shaped dies and mandrels to bend tubular sections without kinking them. Rolling machines are used to form plate steel into a round section. English Wheel or Wheeling Machines are used to form complex double curvature shapes using sheet metal.

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Machining
Main article: machining Fab shops will generally have a limited machining capability including; metal lathes, mills, magnetic based drills along with other portable metal working tools.

[edit] Welding
Main article: welding Welding is the main focus of steel fabrication. The formed and machined parts will be assembled and tack welded into place then re-checked for accuracy. A fixture may be used to locate parts for welding if multiple weldments have been ordered. The welder then completes welding per the engineering drawings, if welding is detailed, or per his own judgment if no welding details are provided. Special precautions may be needed to prevent warping of the weldment due to heat. These may include re-designing the weldment to use less weld, welding in a staggered fashion, using a stout fixture, covering the weldment in sand during cooling, and straightening operations after welding. Straightening of warped steel weldments is done with an Oxy-acetylene torch and is somewhat of an art. Heat is selectively applied to the steel in a slow, linear sweep. The steel will have a net contraction, upon cooling, in the direction of the sweep. A highly skilled welder can remove significant warpage using this technique. Steel weldments are occasionally annealed in a low temperature oven to relieve residual stresses.

[edit] Final assembly

After the weldment has cooled it is generally sand blasted, primed and painted. Any additional manufacturing specified by the customer is then completed. The finished product is then inspected and shipped.

[edit] Specialities
Many fabrication shops have speciality processes which they develop or invest in, based on their customers needs and their expertise:

brazing casting chipping drawing extrusion forging heat treatment hydroforming oven soldering plastic fabrication powder coating powder metallurgy punching shearing spinning English wheeling welding electrical hydraulics prototyping/machine design/technical drawing

And higher-level specializations such as:

Art fabrication

From Wikipedia, the free encyclopedia Jump to: navigation, search Art fabrication is a process or service relating to the production of large or technically difficult artworks. When a lone artist or designer is incapable or chooses not to realize the creation of his or her own design or conception, he or she may enlist the assistance of an art fabrication studio. Typically, an art fabrication studio has access to the resources, specialized machinery, and labor necessary to execute particularly complex projects. "Art fabrication" should not be confused with the term "fabricated sculpture" which refers to a sculpture (usually metal) whose component parts are shaped (usually through bending), and then assembled by way of fasteners or welds (as opposed to a sculpture created through casting).

Manufacturing
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Part of a series of articles on

Industry

Manufacturing methods
Batch production Job production Continuous production

Improvement methods
LM TPM QRM VDM TOC Six Sigma RCM

Information & communication

ISA-88 ISA-95 ERP SAP IEC 62264 B2MML

Process control
PLC DCS

Assembly of Section 41 of a Boeing 787 Dreamliner Manufacturing is the use of machines, tools and labor to produce goods for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale. Such finished goods may be used for manufacturing other, more complex products, such as aircraft, household appliances or automobiles, or sold to wholesalers, who in turn sell them to retailers, who then sell them to end users the "consumers". Manufacturing takes turns under all types of economic systems. In a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more frequently directed by the state to supply a centrally planned economy. In free market economies, manufacturing occurs under some degree of government regulation.

Modern manufacturing includes all intermediate processes required for the production and integration of a product's components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead. The manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in North America include General Motors Corporation, General Electric, and Pfizer. Examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Toyota, Samsung, and Bridgestone.

Contents
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1 History and development

1.1 Manufacturing systems: changes in methods of manufacturing

2 Economics of manufacturing 3 Manufacturing and investment 4 Manufacturing processes 5 Manufacturing categories 6 Theories 7 Control 8 See also 9 References 10 Sources 11 External links

[edit] History and development

In its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. Training was by apprenticeship. In much of the pre-industrial world the guild system protected the privileges and trade secrets of urban artisans. Before the Industrial Revolution, most manufacturing occurred in rural areas, where household-based manufacturing served as a supplemental subsistence strategy to agriculture (and continues to do so in places). Entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. Toll manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm. Craft or Guild system Putting-out system English system of manufacturing American system of manufacturing Soviet collectivism in manufacturing Mass production Just In Time manufacturing

[edit] Manufacturing systems: changes in methods of manufacturing

Lean manufacturing Flexible manufacturing Mass customization Agile manufacturing Rapid manufacturing Prefabrication Packaging and labeling Ownership Fabrication Publication

[edit] Economics of manufacturing

According to some economists, manufacturing is a wealth-producing sector of an economy, whereas a service sector tends to be wealth-consuming.[1][2] Emerging technologies have provided some new growth in advanced manufacturing employment opportunities in the Manufacturing Belt in the United States. Manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs. The clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks. Developed countries regulate manufacturing activity with labor laws and environmental laws. Across the globe, manufacturers can be subject to regulations and pollution taxes to offset the environmental costs of manufacturing activities. Labor Unions and craft guilds have played a historic role in the negotiation of worker rights and