Manufacturing converts engineering materials into components, assemblies and finished products. The appropriate process depends on the material, component geometry, required properties, dimensional accuracy, surface finish, production quantity and cost.
A finished component will often pass through several manufacturing processes. For example, a shaft may begin as a forging, be machined to its final dimensions, joined to other components and finally receive a surface treatment or protective coating.
The following table provides a starting point for selecting and understanding the main manufacturing process families covered by RoyMech.
| Process | What it does | Why it is used | Typical applications | Important considerations |
|---|---|---|---|---|
| Casting | Molten material is introduced into a mould and allowed to solidify in the required shape. | Allows complex shapes, internal cavities and components ranging from small parts to very large structures to be produced. | Engine blocks, housings, pump bodies, impellers, machine bases and complex metal components. | Material castability, moulding process, section thickness, shrinkage, porosity, surface finish, tolerances and production quantity. |
| Forging | Metal is shaped by compressive forces using hammers, presses, dies or related forming equipment. | Produces components with useful mechanical properties and can establish favourable grain flow in highly loaded parts. | Crankshafts, connecting rods, gears, shafts, fasteners and aerospace components. | Material forgeability, grain flow, forging temperature, tooling cost, part geometry, machining allowance and production quantity. |
| Extrusion | Material is forced through or around a die to produce a long component with a substantially constant cross-section. | Efficient production of long sections and profiles, including shapes which would be difficult or wasteful to machine from solid material. | Aluminium profiles, structural sections, tubes, channels and heat sinks. | Material, section geometry, extrusion ratio, die design, dimensional control and required length. |
| Drawing | Wire, rod or tube is pulled through a die to reduce its cross-section and control its dimensions. | Provides long products with controlled diameter, section and surface finish and can improve dimensional accuracy after earlier processing. | Wire, rod, electrical conductors and tubes. | Reduction per stage, material ductility, lubrication, intermediate annealing and dimensional requirements. |
| Powder Metallurgy and Sintering | Metal powders are formed into the required shape and consolidated by sintering. | Can produce large quantities of near-net-shape parts with controlled material composition and relatively little machining waste. | Gears, bushes, filters, structural parts, magnets and specialist materials. | Powder properties, density, tooling, component geometry, porosity, mechanical properties and production volume. |
| Sheet-Metal Forming and Deep Drawing | Sheet material is plastically deformed by punches, dies, presses or other forming tools. | Produces lightweight thin-walled components rapidly and economically, particularly at higher production quantities. | Panels, enclosures, containers, cups, shells and automotive body parts. | Material formability, bend radii, drawing ratio, springback, tooling and production quantity. |
| Machining | Material is removed by cutting or abrasive processes to establish the required geometry, dimensions and surface finish. | Provides high dimensional control and great geometric flexibility and is often used to finish components produced by casting, forging or forming. | Shafts, bearing seats, holes, threads, slots, precision faces, dies and machine components. | Material machinability, tolerances, surface finish, workholding, tooling, material removal rate and production cost. |
| Joining | Separate components are assembled using permanent, semi-permanent or removable joining methods. | Allows complex products to be manufactured from simpler individual components and may permit assembly, servicing or disassembly. | Machines, structures, vehicles, fabricated products and mechanical assemblies. | Joint loading, materials, accessibility, permanence, assembly method, inspection, maintenance and disassembly requirements. |
| Welding | Components are permanently joined by fusion or solid-state bonding processes. | Provides efficient structural joining and allows large or complex fabrications to be assembled from simpler components. | Structures, pressure vessels, pipework, vehicles, frames and fabricated machinery. | Material weldability, joint design, heat input, distortion, residual stress, inspection and production rate. |
| Painting and Galvanizing | A protective coating is applied to the manufactured component. | Principally used to protect surfaces against corrosion, while paint can also provide colour, identification and appearance. | Structural steelwork, machinery, vehicles, fabricated products and outdoor equipment. | Environment, surface preparation, coating system, geometry, inspection, maintenance and required service life. |
| Surface Engineering | The surface of a component is modified or coated to provide properties different from those required in the bulk material. | Allows wear resistance, hardness, corrosion resistance, friction behaviour or temperature capability to be improved without making the complete component from the surface material. | Cutting tools, gears, shafts, bearings, aerospace components, dies and wear surfaces. | Substrate material, wear or corrosion mechanism, coating thickness, adhesion, processing temperature, dimensions and service conditions. |
The processes above are not necessarily competitors. They frequently form successive stages in the manufacture of the same component.
| Manufacturing stage | Typical purpose | Example processes |
|---|---|---|
| Create the basic shape | Produce the initial component or near-net-shape form. | Casting, forging, extrusion, drawing, sintering and sheet forming. |
| Establish final geometry | Produce accurate dimensions, fits, holes, threads and surfaces. | Turning, milling, drilling, grinding and other machining processes. |
| Build the assembly | Connect individual manufactured components. | Welding, brazing, soldering, mechanical fastening and other joining processes. |
| Engineer the surface | Provide wear resistance, hardness, friction control or other specialised surface properties. | Hardening, nitriding, plating, anodising, thermal spraying, PVD and CVD. |
| Protect the component | Provide environmental and corrosion protection. | Painting, galvanizing and other protective coating systems. |
Primary manufacturing processes establish the basic form of a component. The appropriate process depends on material, shape, required properties, production quantity and the amount of subsequent machining required.
Compare casting, forging, extrusion, wire and tube drawing, powder metallurgy, sintering, sheet-metal forming and deep drawing. The guide explains how the processes work, their principal advantages and the types of components for which they are commonly selected.
Primary Manufacturing ProcessesMachining removes material to produce controlled geometry, dimensions and surface finish. It can manufacture a component directly from stock material but is also extensively used as a finishing operation after casting, forging, forming and other primary processes.
Engineering guidance covering turning, milling, drilling, grinding, shaping, planing and sawing together with cutting tools, cutting fluids and CNC manufacturing.
MachiningManufacturing complex products usually requires individual components to be joined after they have been formed or machined. The appropriate joining method depends on whether the joint must be permanent, removable or capable of being serviced.
Overview of engineering joining methods including mechanical fastening, adhesive bonding, brazing, soldering and welding, with links to more detailed RoyMech information.
JoiningCompare fusion and solid-state welding processes including MMA, MIG/MAG, TIG, submerged arc, resistance, friction, friction stir, diffusion, laser and electron beam welding.
WeldingThe material which provides the required strength and toughness of a component does not always provide the surface properties required in service. Coatings and surface treatments allow these requirements to be considered separately.
Engineering guidance on painting and hot-dip galvanizing for corrosion protection, including surface preparation, coating systems and practical design considerations.
Painting & GalvanizingEngineering introduction to surface hardening, electroplating, anodising, thermal spraying, nitriding, diffusion treatments, ion implantation, ceramic coatings, CVD and PVD.
Surface EngineeringBefore selecting a process, establish what the component must achieve. Important questions include: