Metalworking is, as the name suggests, the process of working with metals to create individual parts. There is a wide range of technologies that are used within metalworking to create all types of products from small pieces of jewelry all the way to building components and large-scale constructions.
- Metal Forming
- Metal bending
- Cutting metal
- Metal Joining
- Metal casting
- What type of metalworking should be used?
- Which materials are used the most in metal fabrication?
Most metalworking processes fall into three categories: forming, cutting, or joining. Separately stands casting, which is also one of the most widespread methods of getting metal parts. Casting involves pouring metal into a mold, after which is cooled and solidified, and we cover it in more detail in a different guide. Here, though, we will attempt to provide an overview of the most prevalent metalworking processes in the manufacturing industry today.
Forming is the process of fashioning metal objects through deformation without adding or removing any material. Typically, it is performed using heat and/or mechanical loads to make the desired shape. Forming itself includes various manufacturing technologies like bending, extrusion, forging and more.
Metal forming is used for large-scale objects and big volume runs due to expensive machinery with high stresses needed. Using this technology for small production would not be cost-effective. Metal forming takes advantage of materials’ plasticity, which allows reshaping a blank piece (sheets, tubes, blocks). As a result, the most commonly used in forming metals are steel, aluminum, brass and copper.
Metal bending is a manufacturing process that uses ductile materials; most commonly sheet metal is processed through equipment like machine presses. Metal bending is considered to be quite cost-effective for batches of low to medium quantity. Basically, there are three types of bending on a press brake: air bending (most common), bottoming and coining.
Generally speaking, in bending a metal sheet (or form) is placed under a die that is pressed or punched into it. To permanently deform a metal piece, the machine over-bends the piece to compensate for the material's spring back. Through using different angles or die shapes, bending can deliver various shapes depending on the need.
Forging is among the oldest metalworking processes. It uses local compressive forces to shape the metal. Nowadays, industrial forging is done with specialized pressing equipment (hammers) that can weigh more than thousands of pounds! There are hot and cold forging methods, which are applied depending on the material type.
One of the significant advantages of forging is produced parts are stronger machined or cast ones. When metal is shaped during the forging process, its internal grain texture slowly deforms following the general shape of the part. After the process is complete, the finished product has vastly superior properties.
Cutting is a process during which a part is shaped by removing excess material using different tools. This process includes such technologies as CNC milling, routing, laser cutting and turning.
Machining is a collective title for numerous processes in which a piece of raw material is cut into a desired shape and size by computer-controlled equipment. Such methods are often referred to as subtractive manufacturing, as opposed to additive manufacturing (3D printing) which builds a product from scratch.
Machining is associated with the production of metal parts, though it can be used for a wide range of materials including plastics, woods, composites, and more. Probably, one of the reasons for metal materials’ domination is that setup costs for using industrial-grade machinery are hefty. The three primary (and most common) machining processes are milling, routing and turning.
Milling is a range of operations in which a cutting tool rotates, bringing cutting edges to bear against a workpiece. Milling machines are the principal machine tool used in milling. They can deliver diverse parts and are compatible with many materials. The limitations in capabilities are usually tied to the machine's RPM and axes.
CNC routing is similar to milling, with some CNC routing machines capable of performing almost the same tasks as that of milling machines. Their primary functions are to cut, engrave and carve objects out of a workpiece - essentially a replacement for the usual hand-held tool (like a drill), but with the help of a computer-control to eradicate human error.
Machining processes that rotate a workpiece to move metal against the cutting tool are called turning. Lathes are used in turning as the leading principal machine tool. Turning works best for getting round objects and symmetrical components.
Laser cutting works just like regular machining. The only difference is that instead of mechanical tools, it uses a laser to remove portions of the material. This technology is versatile as there are many laser types and powers available. The distinctive advantage is that laser cutting can produce parts quicker and provide a better edge finish as the beam polishes and melts it. We provide a more detailed overview of laser cutting in this guide.
Metal Joining stands for merging several parts of metal by processes like welding, riveting, bonding, and others. Commonly, heating or a chemical reaction is used to melt edges of parts and join them. Such a method allows the versatility of possible shapes and results. Some metal 3D printing processes such as DMLS and EBM could also be called forms of welding since they melt together metal powder grains.
Metal welding is a fabrication process that is based on joining materials via fusion - a combination of pressure mixed with heat. In general, a filler material is added to form the welded joint, so that in some cases, it can become even stronger than the original medium.
At the same time, the welding process must secure the filler metals and melted metals from being contaminated and oxidized. Welded operations can be categorized according to different energy sources that are used, among which are gas flame, electric arc, laser, and ultrasound. The most popular welding methods include:
- Oxy-fuel welding (oxy welding) uses fuel gases and oxygen to weld and cut metals.
- Shielded metal arc welding (electric welding) uses an electrode that is coated in flux to protect the weld puddle. The electrode holder holds the wire as it slowly melts away.
- Gas tungsten arc welding (inert gas) uses a non-consumable tungsten electrode for producing the weld. However, the weld area has to be protected from atmospheric contamination by an inert shielding gas such as argon or helium.
- Gas metal arc welding (inert gas) uses a wire feeding gun that feeds wire at an adjustable speed and flows an argon-based shielding gas or a mix of argon and carbon dioxide (CO2) over the weld puddle to protect it from atmospheric contamination.
Metal casting is a metalworking process that has been around since ancient times and is still widely used for making sculptures, tools, and jewelry. Most popular methods include lost-wax casting and sand casting. They are subdivided by the mold material (e.g. sand or metal) and pouring method (such as gravity or vacuum). Casting is great for getting custom parts in small batches or single units. It can deliver complex shapes and geometries through fully melting metal and then pouring it into a mold.
Each metalworking process has its pros and cons - that’s why the manufacturing method should be chosen based on the budget and application. We recommend taking a closer look at each of the manufacturing processes in our manufacturing guides and, if necessary, contact us.
There are some differences in metals used via each metal forming technology. Generically speaking, the most commonly used ones are:
- Steels – are very versatile and durable metals. They are used in construction, tooling, machinery and, thus, processed through forming a lot.
- Copper – is ductile and conductive. There is a high demand for copper parts in the electrical and construction industries, so many copper parts are manufactured using forming. Copper is also hard to process via some other methods (like laser cutting or machining, which is possible but tricky).
- Aluminum – aluminum is easy to form and, more importantly, budget-friendly. Its mechanical properties are fine, too, so aluminum parts are manufactured in great quantities.
- Brass – is a copper and zinc composite with excellent properties. It is diverse and can be used for nuts, bolts, fittings, and knobs.
This list is surely not complete as many other metals can be processed. However, aside from materials’ properties, production costs give a huge impact.