Metal manufacturing encompasses a wide range of methods that are used to alter the condition of metallic materials. Metal processing is most often performed for two main purposes: to shape the metal, such as in metal spinning and metal stamping, or to alter the state of the metal’s surface, such as in galvanization or coating. Of these two purposes, metal forming is more common, and it includes processes like metal injection molding, metal casting, metal extrusion and more. In addition, there are many processes that are more unique and specialized. For instance, there are material specific processes like aluminum extrusion or processes that specifically form sheet metal. Although there is a wide variety of metal manufacturing processes, some of the most common methods of metal processing for industrial applications include electroless nickel plating, metal etching, roll forming, water jet cutting, die casting, forging and metal stamping.
Aluminum casting is the process of creating aluminum shapes with a die caster. Die casting is a very commonly used metal shaping process that is used to create metal shapes for use in industrial, commercial and consumer products contexts.
In industry, metal castings are used extensively; they are used both as manufacturing equipment components as well as in the products produced by manufacturing equipment. The automotive industry in particular makes extensive use of aluminum castings because of aluminum’s heat resistance and durability. Aluminum castings can also be found on aircraft, watercraft, in heating and cooling systems and in many other kinds of equipment. Aluminum die casts are lightweight and feature excellent corrosion resistance, very favorable mechanical properties, high thermal and electrical conductivity and strength at high temperatures.
Cold headed parts are finished or stock shapes produced through a specialized process more broadly known as cold working. Although cold heading is a popular option, it is part of this larger group of manufacturing processes also referred to as cold forming. As the name would suggest, none of these techniques involve heat, but instead materials are processed and formed at ambient temperatures. While the name might imply that the temperature is further reduced for cold metallurgical processes, most are carried out with machines and materials left at room temperature.
Metal parts produced through the forging process are known as forgings. During forging, a compressing force pressures the metal, causing plastic deformation and an alteration of the metal grain flow, whereby the metal assumes the shape of the forging die. Note that, in this process, while metal may be preheated, it is never melted or poured.
Forgings are made through two main forging methods: closed die forging, also known as impression die forging, and open die forging. In closed die forging, which is the most common die forging method, a hammer and anvil press or hammer preformed metal blanks, called ingots, into a die or set of dies that are shaped as three-dimensional negatives of the part-to-be. During this process, the hammer and anvil completely cover the workpiece, which forces the metal to spill into all areas of the die.
Forgings serve as components of ships, tractors, engines, tools, airplanes, automobiles, missiles, material handling equipment and more. In addition, the forging process presents design flexibility, requires minimal secondary operations and consistently produces extra strong metal parts and products with very few defects.
Grey, or gray, iron castings are iron alloyed parts produced in foundries, not to be confused with forges, where they are formed via closed mold operations for applications in a wide variety of industries. Industries that grey iron castings serve include agriculture, architecture, automotive, construction, electronics, irrigation, machinery construction, transportation, and ventilation. Grey iron castings lend durability and strength to any operation for which they are used.
To acquire grey iron, metalworkers must first mine iron ores or iron oxides and then process it in a special type of blast furnace, called an electric induction furnace or a cupola. The generally accepted composition of cast grey iron is 95% iron by weight, plus 1 to 3% silicone and 2.1 to 4% carbon. The high amount of silicone, which produces graphite when heated, is the element responsible for grey iron’s coloring. It manifests itself when fractures form, revealing its graphitic microstructure. The exact appearance of individual grey iron depends on both temperature and timing. Other than appearance, variable properties of castings include thermal conductivity, energy dissipation, resistance to wear and deformation, and melting point. Additional elements that may appear in grey iron castings, whether intentionally, to alter specific properties, or unintentionally, include manganese and sulfur; the latter is often added into molten iron to increase its hardness. When metalworkers have reached the grey iron mixture they want, they proceed to casting.
Investment casting is a manufacturing method that is used to create complex and detailed industrial parts and shapes. This is accomplished by starting with a wax model of a part that is then turned into a mold. The mold, in turn, is filled with molten metal.
The process of investment casting starts with the creation of a wax model that is then attached to a sprue. Hundreds of wax model molds can be fixed to the same sprue at one time, this is called a tree. The tree is dipped into a slurry compound several times before it is sprinkled with an abrasive material resembling sand. Once the investment around the wax is thick enough, it is placed in an industrial oven where temperatures exceed 1000 degrees Fahrenheit. The wax might melt and drip during this time, but it keeps its shape. Whatever metal that is being used is heated until it is in liquid form and then poured into the hollow mold. Once the metal has cooled to the point that it is no longer red hot, the shell around it is removed and the cast metal parts are cut off of the sprue.
Metal spinning, often called spin forming, is a cold metalworking process in which a flat metal disc affixed to a lathe mandrel is rotated at high speeds and formed by shaping tools. A metal spinner applies pressure to the rotating disc, which is called a blank, using several tools, which are called spoons, to shape the metal over a mandrel. This pressure can be applied by a single tool or by multiple tools. The finished product should have no wrinkling or warble, and the process is quick and cost-effective. An average metal piece will take only five to ten minutes to be formed, and very little metal waste is produced per part.
Numerous industries utilize solid metal parts made of powdered metal. Powdered metal components, which are made from powdered metal via powder metallurgy, can be found in applications spanning across industries such as lawn and garden, computer, electronics, hardware, and automotive.
More specifically, powder metal parts include magnetic assemblies, filtration systems, structural parts, and automobile components. Powder metal gears are inherently porous and they naturally reduce sound, making them a suitable component to the sintering process. Bearings and bushings can simply be produced by way of sintering, however, they may require a secondary sizing operation because their fabrication leaves little room for error.
Roll formed parts are metal products shaped by a series of rollers, during the process known as roll forming. Most metals can be roll formed, but the most commonly roll formed metals are brass, steel, zinc, aluminum and zirconium.
Roll formed parts are valued for many reasons, among them uniformity, accuracy, structural integrity and low tooling costs. They serve a myriad of industries, such as: building construction and architecture, carpentry, commercial automotives and home improvement. They’re also used to fabricate a wide variety of commercial, consumer and industrial products.
Examples of common roll formed products for carpentry and building construction include: angle irons, aluminum angles, steel angles, metal channels and metal trim. Angles are designed to provide support in two directions, and frequently feature slots or holes for connecting parts.
Springs can be found as a necessary component in many devices, machines, and systems. A spring is an elastic device that applies a resistant force when compressed or stretched. Springs are used to store and absorb energy and maintain force or tension in the application for which it is designed.
Some of these applications include circuit breakers, solenoid valves, writing instruments, and electronics. Springs come in four main styles, which are compression springs, extension springs, torsion springs, and flat springs. The combination of a flat spring and a coil spring is known as a constant force spring.
Aside from these four major categories, springs can be found in a wide range of styles. Industrial springs are typically made from thick wire, while smaller springs can be made from wire that is flexible and thin. Some of these springs are too small to be seen by the naked eye.
Wire forms consist of various shapes and parts that have been fabricated through the manipulation of wire, which includes anything that alters the shape of the wire such as wire cutting, bending or heat treating. Vital to numerous applications, wire forms serve an extensive range of industries such as: commercial and retail, for wire displays used for product placement such as point of purchase (POP) displays and wire grids; industrial manufacturing, for wire racks and wire shelves that are used in storage systems as well as for wire guards as protective equipment for machinery.
Wire mesh is an industrial product of weaved interlocking metal wires welded or sintered into a wire mesh with evenly spaced, uniform openings that is used as a material for a wide variety of filtering, screening, structuring and protecting in industrial, agricultural and residential applications.
In industries like petro-chemical processing, screen printing, pharmaceutical manufacturing and food and beverage processing select wire mesh materials on a case to case basis, depending on their application requirements. Some application require a specific weave pattern. The most common of these are are twilled square mesh weave, plain square mesh weave, plain dutch weave, reverse plain weave and twill dutch weave. Each weave pattern brings something different to the table. For instance, plain square meshes, which are made from shute wires or lateral wires and warp wires or longitudinal wires of equal gauge, are perfect for basic mesh operations.