Types of Manufacturing Process
What is a Manufacturing Process?
Every engineered product starts as a raw material and ends as a finished component through one or more manufacturing process. There are six types of manufacturing process, and understanding what each type does — and how it changes the material — is the foundation of the whole unit. Each process type is suited to certain materials and certain scales of production, so choosing the right one is a core engineering skill.
Wasting
A wasting process removes material from a workpiece. The material that is cut, drilled, filed or turned away becomes waste — hence the name. The starting block is always larger than the finished part. Common wasting operations include sawing, drilling, filing, turning on a lathe, and milling on a CNC machine. Wasting processes are widely used for metals and plastics, and they can achieve very precise dimensions and smooth surface finishes. The main disadvantage is the waste generated, which adds to material cost and must be disposed of safely.
Wasting processes remove material from a workpiece to achieve the desired shape. The material removed becomes waste swarf or offcuts. Where possible, these can be collected for recycling, so careful planning minimises material loss.
Shaping
Shaping processes give a material its form using a mould or a pressing tool, without removing material. In casting and injection moulding, molten or softened material fills a mould cavity and solidifies into the desired shape; powder metallurgy compacts and sinters powder. Sand casting, die casting, and injection moulding are all shaping processes. Shaping is particularly efficient for complex three-dimensional forms because the mould defines every detail in a single operation. It suits metals and polymers and is commonly used in high-volume production.
Shaping uses a mould or a pressing tool to give material its form — casting and injection moulding fill a mould cavity, while powder metallurgy compacts and sinters powder. Forming, by contrast, starts with a solid workpiece that is deformed plastically by applying force — forging, press forming, vacuum forming and strip heating are all forming processes. In both cases no material is removed, but the mechanism is different: shaping relies on fluidity, forming relies on plasticity. This distinction is commonly tested in the exam.
Forming
Forming processes change the shape of a solid material by applying mechanical force, heat, or both, without removing any material. Forging hammers hot metal into shape; press forming bends sheet metal; vacuum forming stretches a softened thermoplastic sheet over a mould using atmospheric pressure. The material is plastically deformed — meaning the change is permanent. Forming is valued because it generates very little waste and can improve the mechanical properties of metals by aligning the grain structure. It is widely used in the automotive, aerospace and packaging industries.
The six process types are wasting, shaping, forming, additive, joining, and finishing. Only wasting removes material; shaping and forming change its form; additive builds it up; joining combines parts; finishing alters the surface.
Additive Processes
Additive processes build up a product layer by layer from a digital model, adding material only where it is needed. 3D printing using fused deposition modelling (FDM) is the primary additive process on the specification. A thermoplastic filament is melted and deposited in precise layers by a print head that follows a computer-generated path. Additive manufacturing produces virtually no waste, can create complex internal geometries impossible to achieve by wasting, and requires no tooling. It is ideal for prototypes and one-off parts but is currently slower and more costly for large production volumes than traditional methods.
Joining
Joining processes connect two or more components or materials. They can be permanent — such as brazing, MIG/MAG welding, or riveting — or temporary, such as mechanical fastening with nuts and bolts or self-tapping screws. The key characteristic is that joining does not change the form of the individual parts significantly; it combines them into an assembly. Choice of joining method depends on the materials involved, the strength required, whether the joint needs to be dismantled, and the production volume.
Finishing
Finishing processes are applied to the surface of a completed component to improve its appearance, protect it from corrosion or wear, or meet a particular functional requirement. Painting by brush or spray and powder coating are the finishing processes named in the specification. Finishing does not change the overall dimensions of a part to any significant degree — it modifies only the surface. It is usually the final stage in manufacture and is important for both commercial appeal and long-term durability.
Students often call drilling a 'forming' process because it changes the shape of a workpiece — but drilling removes material, so it is wasting. Similarly, injection moulding is shaping (liquid polymer fills a mould), not forming (which requires a solid workpiece and plastic deformation). When answering process-type questions, ask yourself: is material being removed (wasting), poured/injected in liquid form (shaping), deformed as a solid (forming), built up layer by layer (additive), connected to another part (joining), or treated on its surface (finishing)? Apply that checklist and you will select the correct category every time.