Metals are among the most versatile and essential materials in modern manufacturing. Their remarkable range of properties – from strength and conductivity to malleability and durability – makes them indispensable across virtually every industry. There is hardly a finished product on the market that does not rely on metallic components in some form.
Shaping metal into precise forms requires specialist machinery, and the variety of equipment available reflects the breadth of metalworking applications. Once extracted, metal can be melted down and reshaped repeatedly, making it one of the most recyclable and adaptable raw materials available to manufacturers today.
Prototype-forming by casting and pressure casting
Metal is extracted from ore in the smelter and cast into slabs at the smelting plant. This stage of metal processing is known as prototype-forming, which shapes metal without the use of machining techniques – a process of primary interest to the semi-finished product industry. Pressure die casting machines and cast iron plants process metals directly into final products, while foundry equipment such as furnaces, ladles, continuous casting machines and extrusion machines are used to manufacture profiles and semi-finished products.
Shaping of metals
After prototype-forming, metal is rolled and processed into blocks, slabs or strips as the first steps in shaping. It is then transformed from one form to another through pressing, rolling, bending, folding or forging, with a dedicated machine type for each operation.
- Rollers are used in steelworks and sheet metal operations to straighten and assemble thin sheets.
- Presses form a wide variety of finished products from metal blanks.
- Folding presses bend sheet metal to a desired angle.
- Forging presses handle large-scale, solid workpieces – particularly components that will be subjected to significant mechanical force or strain.
Forging produces exceptionally hard and resilient results. For complex workpieces such as crankshafts, several forging tools are typically applied in sequence, each incrementally shaping the workpiece toward its final form.
These shaping processes do not alter the mass of the metal – unlike most other metalworking operations. Press brakes, shearing machines and general presses all fall under the category of sheet metal processing machinery.
Separating processes
Separating processes cover the machining of workpieces using equipment such as lathes, milling machines, sawing machines and grinding machines.
The most straightforward cutting tools in metal processing are sheet metal cutters and shearing machines, which cut material in a single linear direction. Punching and notching machines can then remove predefined sections from a blank.
For fine machining, CNC milling machines are the preferred solution – capable of working metal in any required direction and producing highly complex contours. Lathes, by contrast, are used for rotationally symmetric turned parts. Both mills and lathes belong to the broader field of chip-removing machining.
At the top of the milling hierarchy are CNC machining centres, which deliver both high repeat accuracy and consistent quality across complex manufacturing tasks. These represent some of the most sophisticated and capable machines in the metal industry.
Gear cutting machines are a specialised form of milling and grinding equipment, designed to produce gears and toothed wheels with the consistent precision required even in serial production. Similar in principle to conventional machining centres, they incorporate specific functions tailored to gear geometry. Gear cutting machines – including hobbing machines and gear grinding machines – are typically paired with a downstream hardening facility to maximise the durability of the finished gears.
Drilling machines remain a widely used and straightforward piece of equipment, employed for blind holes, through-holes and thread cutting. They are now frequently integrated into CNC machining centres.
Finishing and surface preparation are carried out by grinding, polishing and lapping machines, which remove material in increments as small as a hundredth or thousandth of a millimetre for highly precise results. In addition to achieving tight tolerances, these machines also prepare metal surfaces for galvanising – chrome finishing, for instance, requires thorough polishing beforehand.
Erosion machines (EDM machines) represent a specialised category of material removal equipment. Operating via electrical discharge rather than mechanical contact, they create highly precise cavities in metal blocks. EDM machines are widely used in tool and die manufacture, producing durable, precise tooling for presses, punching machines and casting equipment.
Cutting metals without tools
Beyond mechanical separation processes such as sawing, milling and grinding, several thermal and fluid-based cutting methods are available that require no physical cutting tool.
Flame cutting is the simplest and most cost-effective approach, using a high-temperature flame fed by fuel gas and oxygen to cut through metal. It is a relatively imprecise method, producing gaps of several millimetres even under CNC guidance, and generates a heat-affected zone along the cut edges where the metal hardens significantly. Where this is undesirable for the finished product, the affected zone must be removed by milling.
Plasma cutting operates on a similar principle but delivers greater precision and produces smaller heat-affected zones. With CNC guidance and a cutting table, plasma cutting can achieve accurate contours even on thick material. Both flame and plasma cutting are suited to material from a few millimetres up to several centimetres thick.
For thin sheet material, laser cutting is the preferred choice. It produces extremely fine, precise cuts with minimal material loss and no significant heat-affected zone. Unlike flame cutting, laser cutting cannot be performed with a hand-held device – laser cutting machines are stationary CNC work tables.
Where cold cutting is required, water jet cutting offers an established solution. A highly pressurised jet of water combined with an abrasive medium cuts through sheet material without generating any heat-affected zone, making it suitable for applications demanding very high precision. The process is also known as aqua cutting.
Metal joining
Welding is the most widely used process for joining metals. Electric arc and gas-shielded arc welding are the most common methods, available in formats ranging from hand-held tools to large stationary systems. Friction welding, while less common, is a simpler alternative. Submerged arc welding (SAW) is the preferred method for very thick sheet metal and is used primarily for processing large components.
Additional joining methods include riveting and adhesive bonding.
Metal surface treatment
Alongside grinding and polishing, a range of surface treatment equipment is used in metal processing, broadly divided into coating systems and treatment systems.
Coating machines
Galvanic coating systems are the primary coating technology in metal processing. They apply a thin layer of zinc, copper, gold or chrome to the finished product. Hot-dip galvanising plants are the most straightforward of these systems and are widely used on steel products to provide lasting corrosion protection. Chromium plating systems are more complex, using a multi-stage dipping process to coat metal products in a thin, bright chrome layer.
Powder coating offers an alternative to galvanising. An electrical charge causes the metal product to attract a sprayed plastic-based powder, which is then fused in a furnace to form a seamless, corrosion-resistant surface in the desired colour.
Metals can also be finished using a range of painting and adhesive coating processes.
Treatment machines
The principal metal treatment systems are hardening and tempering plants, which use heat to create a resilient surface zone. An annealing furnace heats the workpiece, which is then rapidly quenched in an oil bath to achieve a hardened, tempered finish. Hardened components are used wherever abrasion resistance is critical – gear wheels, bearing shells, shafts and slide paths are commonly surface-hardened to extend service life.
Measuring and testing machines
A finished product is only as reliable as its least accurate component. A broad range of measuring and testing equipment has therefore been developed to verify that every part meets the required properties and dimensions. Metal testing divides broadly into destructive and non-destructive methods.
Destructive testing procedures
The universal tensile testing machine is the classic tool for destructive testing. It clamps a metal sample and applies tension until fracture, precisely defining the material's elastic and plastic deformation zones.
Notched impact hammers test material resilience by striking a metal sample transversely with a rotating hammer, measuring the force required to break it.
Hardness testing machines penetrate a prepared sample with a needle at a defined force, measuring the depth of penetration to determine hardness. Manual hardness testing is increasingly being replaced by automated systems.
Where a comprehensive overview of material composition is required, spectrometers examine the metal's structure and alloy content in detail.
Non-destructive testing procedures
Non-destructive methods include visual, tactile and subsurface inspection approaches.
Visual inspection encompasses everything from rulers and measuring tapes to verniers, test gauges, magnifying glasses and microscopes. These tools are increasingly complemented by high-precision laser measuring devices.
Tactile methods include 3D coordinate measuring machines (CMMs), which guide a sensitive probe or scanning head across a metal product to verify dimensional accuracy at predefined points – a technique commonly applied to welded constructions.
Subsurface inspection without material destruction is achieved through X-ray and ultrasound testing. X-ray delivers high precision and reliability but involves radiation exposure, which can be a practical consideration for lengthy tests on thick material. Ultrasound is faster, safer and available in both hand-held and stationary configurations.
Lifespan of metalworking machinery
Even the finest lathe – or any machine tool – will eventually reach the end of its useful life. Unlike woodworking machines, metalworking equipment operates under far greater forces, and even the most robust designs wear out over time.
A further consideration is the pace of innovation in the metalworking sector, which is considerably faster than in woodworking. Tolerances grow ever more precise, the complexity of required contours continues to increase, and productivity demands rise constantly. As a result, older but still functional machines can become obsolete, replaced by higher-performance modern alternatives.
Buying second-hand metalworking equipment
Prospective buyers of used metalworking machinery should carefully assess the tolerances, complexity and productivity levels they need to achieve. Each machine type has specific technical parameters that can guide the purchasing decision:
- Number of firing cycles for pressure casting machines
- Pressing forces and cycle rate for punches and presses
- Feed rates for milling machines and lathes
Once minimum performance requirements are established, the search for a suitable machine can begin in earnest.
Inspecting used metalworking machinery
When a candidate machine is found, a thorough inspection is essential. Operating hours, visible wear, and overall condition all offer valuable insights into the equipment's history and reliability. Ideally, the machine should be tested under real working conditions – producing a defined sample piece and measuring it precisely to verify dimensional accuracy. This also reveals the machine's production speed, which is a critical factor: discovering too late that output rates fall short of requirements is a costly mistake. It is generally wiser to accept a minor compromise on tolerance than to settle for inadequate productivity.
Maintaining and repairing metalworking machines
Maintenance and repair of metalworking equipment should always be entrusted to trained specialists and qualified service companies, of which there are now many. Some are capable of more than simply restoring a machine to its original specification – they can actively enhance its capabilities, extending its working life significantly. In certain cases, improvements to productivity, precision, rigidity and functionality can bring a refurbished machine close to the performance level of a new one.
That said, every metalworking machine has a point beyond which further overhaul is no longer economically viable. Consistent maintenance, timely repairs and specialist expertise can push that point further into the future – but not indefinitely.
The range of companies producing metalworking machines is as diverse as the many approaches to processing metal. As in the woodworking sector, the market includes both manufacturers offering broad portfolios of machines and equipment, and specialists focusing on a narrower range of solutions.
On the second-hand market, many companies also play an important role in keeping used machinery from discontinued brands operational across a wide range of applications – allowing operators to achieve excellent results while benefiting from the cost advantages of buying pre-owned equipment.
The following overview introduces some of the best-known metalworking machine manufacturers and the types of machines associated with them.
- ALZ-METALL
- AMADA
- DECKEL
- EMCO
- FLOTT
- KALTENBACH
- KASTO
- MAZAK
- OPTIMUM
- TRUMPF