Metalworking

What is metalworking?

Metalworking is the process of machining and forming metals to produce useful tools, objects, equipment components and building structures. Metalworking occupations typically involve forming, cutting and joining processes as well as methods such as cutting, welding, casting and moulding. Ferrous and non-ferrous metals such as steel, aluminium, gold, silver, bronze, iron and others are used in metalworking.
Metalworking has a long history dating back thousands of years, and it is still an essential part of many industries today. From the manufacture of car parts to the construction of spacecraft, metalworkers play an important role in our world.

Metal
processing

The history of metalworking

Precious metals have been processed into objects and valued by ancient civilisations for thousands of years, from the pharaohs in Egypt to the Mayans in North America. The oldest known evidence of metalworking is a copper pendant found in Iraq dating back to 8,700 BC.

Metalworking was a way for civilisations to communicate their status, religious beliefs and symbolism through artefacts, and a practical method of building tools and structures. It was practised by artisans, blacksmiths, alchemists, builders and many others around the world, all specialising in different aspects of metalworking. Many old forging techniques are still used today, from soldering to welding.

Metallic ores have been extracted from the earth for thousands of years, making metalworkers an important source of metals. For example, they can extract iron from mineralised sand and mine precious metals such as silver from the earth. In modern times Metals even more important for mankind and progress in technology and transport. Metal processing is omnipresent, from the manufacture of electronics to automobiles.

Metalworking techniques

Metalworking techniques can be used to create anything from small decorative objects to large structures. Although many metalworking techniques are similar for different materials, the properties of the metal you are working with will have a major influence on your work and the desired end result.

Cutting

When cutting, the material is removed from the metal by milling, routing, turning and technologies such as CNC (Computer Numerical Control) machines. Plasma cutters are gas-powered torches that use argon and hydrogen gas to remove material and create holes in metal. Cutting is often used in metalworking shops, car repair and construction.

Fügen

When joining, several Metal parts by welding or soldering with heat. Welding is a manufacturing process that uses a welding machine to join ferrous and non-ferrous metals and is well suited for larger projects. Soldering is a joining process in which different types of precious metals are joined together by melting solder and is well suited to small projects. New technologies are constantly being developed as metalworking advances.

Reshaping

Under Reshaping is the forming and production of metal objects without adding or removing material. This process is made possible by a combination of heat and pressure. Both forging and the bending are essential methods of metal forming. In forging, the metal is heated in the forge and then bent into the desired shape with a hammer. To create a bend or curve in the metal, it is heated in the forge, then held over the anvil horn and struck with the hammer to create the desired curve. The English wheel is a tool with which metalworkers can easily shape and form cold materials such as aluminium or steel.

Pouring

Metal casting is a metalworking process that can be traced back to around 4000 BC and is still used to make sculptures, tools and jewellery. Ever since we learnt to melt metals, metal casters have been pouring molten metals into cavities made of stone, plaster, sand and even bone. Metal casting is inexpensive and time-saving and offers the possibility of producing several copies of a piece.

The most common methods of casting metal are lost wax casting and sand casting. In the lost wax process, the workpiece is carved or moulded in wax, a plaster mould is created around it and the wax is then burnt out. In sand casting, sand is used as the moulding material. The sand is combined with a binding agent, e.g. clay, and provided with a gate. Molten metal is then poured into the mould to create a solid object.

Separation processes and separation techniques

Metalworking involves cutting and separating metals to build structures, make tools and much more. There are numerous cutting methods for metalworking, ranging from simple hand tools to a variety of advanced machines and equipment.

Milling

When milling, precise quantities of material are removed from a larger part. A milling machine rotates a cutting tool and brings it into contact with a workpiece. The milling machine and lathe are the cornerstones of any machine shop and can produce workpieces with great precision, repeatability and accuracy.

Turning

Turning is a machining process in which a cutting tool moves linearly while the workpiece rotates, strategically removing material from the workpiece. The material can be removed from both the depth and width of the workpiece. Lathes are traditionally used as the primary machine tool for turning. As technology advances, CNC machines are also being utilised for a more automated process.

Loops

Grinding is a grinding process used to remove material from the workpiece, typically in the finishing stages of metalworking. Grinding machines range from hand-held angle grinders to bench grinders and more advanced CNC machines. These machines can vary greatly in size and precision. Grinding produces very fine surfaces and precise cuts using a grinding wheel made of stone, diamond or inorganic material.

Drilling

Drilling involves making holes in metal using a drill, hand drill or CNC machine. Make sure you lubricate your drill bits with cutting fluid to prolong the life of the tool and prevent overheating. This will ensure a smooth and accurate hole and also prevent chattering or unsafe drilling.

Joining processes & joining techniques

When joining metals, heat and pressure are used to create a larger part or build a structure. Welding and riveting are excellent joining techniques for larger projects that carry weight, while soldering is a process for joining smaller materials, such as jewellery and sculptural objects.

Welding

Metal welding is a manufacturing process in which materials are joined together using pressure and heat. Different types of welding work indoors, while others are best used outdoors. Welding is used to forge swords, build ships, construct structures and much more. There are many different types of welding, each with specific practical applications. In this guide, you will learn more about the different types of welding.

Soldering

Soldering is another method of joining metals in which a filler metal is melted onto the metals to be joined to create a reliable electrical bridge. A low-temperature alloy is melted into the joint and fuses the metals into a solid piece. Metalworkers use either a conventional soldering iron or a gas-fuelled torch to join precious metals. Soldering is often used in sanitary engineering, electronics and metalwork for the manufacture of musical instruments.

Rivets

Rivets are durable mechanical fasteners that can create kinetic connections in a workpiece or reinforce the structural integrity of a larger object. They are ideal for joining parts that are lightweight and require high strength. Before welding was used in the construction of buildings and structures such as the Eiffel Tower and the Sydney Harbour Bridge, rivets were used at the joints to join the metal. Rivets are smooth metal cylinders with a head at one end before they are inserted.

Forming processes & forming techniques

The forming and manipulation of the shape of metal can be done both when the material is hot and when it is cold. Which forming process you choose depends on the metal you want to form, the equipment you have available and the desired end result.

Forging

Forging is one of the oldest metalworking processes used to mould and shape metal. The metal is heated in the forge, then hammered and bent into the desired shape. The blacksmith may use a hammer to forge smaller objects, or an industrial hammer for larger projects. Forged metals are incredibly strong and are usually made from iron and steel.

Roll forming

Roll forming is a process in which a long strip of sheet metal is continuously bent through a roll forming mill at room temperature. Unlike other metal bending methods, roll forming is inherently flexible and precise and can shape metals up to a quarter of an inch thick.

Rollers

Rolling is a metal forming process in which metal material is passed through a rolling mill to reduce the thickness or make the thickness uniform. The process can be carried out hot or cold. Hot rolling is normally used to Production of sheet metal and larger workpieces. Cold rolling is well suited to smaller items, increases the strength of the material and improves the surface finish so that less reworking is required.

Casting processes & casting techniques

In the metal casting process, solid metal objects are formed by pouring molten metal into a mould, where it cools and is removed from the mould. Metal casting is cost and time efficient. Common processes for casting metal are investment casting or lost wax casting, die casting and sand casting.

Investment casting or lost wax process

Investment casting is a process in which molten metal is poured into a mould made from a wax model. Sprues are attached to the model and a plaster mould is formed around the wax. The mould and the wax are placed in a kiln to burn out the wax. The metal is then melted and poured into the plaster mould using a vacuum or centrifugal casting machine.

Die casting

Die casting is an automated and fast process in which molten metal is pressed into a mould under high pressure. The mould consists of two machined steel tools and the metal is injected directly into the mould at high speed. In die casting, alloys with a low melting point are usually used, such as zinc, copper, aluminium and magnesium.

Sand casting

In sand casting, which is often used in foundries, sand is used as the moulding material. The mould is made by combining sand with a binding agent, e.g. clay, and is provided with a gate. Molten metal flows into the mould to create a solid object. Sand casting is the most common metal casting process and is relatively inexpensive.

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