Additive Manufacturing Technologies: Processes, Materials and Applications
Updated: 1 day ago
Choosing an additive manufacturing technology starts with the part you need to make. Its material, geometry, tolerances, surface finish, production quantity and qualification requirements all affect which process is suitable.
There is no single “best” 3D printing process. A polymer process suited to a lightweight enclosure may be irrelevant to a metal aerospace component. And a process that can produce a complex shape may still require support removal, heat treatment, machining or inspection before the part is ready to use.
This guide compares the main additive manufacturing technologies, the materials and applications associated with them, and the practical constraints to consider when moving from a successful print to a production route.
What counts as an additive manufacturing technology?
Additive manufacturing (AM) builds a part by adding material according to a digital design. The exact method depends on how the material is supplied and joined: it may be extruded through a nozzle, fused in a powder bed, cured in a vat, or bonded as droplets or sheets.
ISO/ASTM 52900 groups AM processes into seven categories: binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, sheet lamination and vat photopolymerisation. These categories describe how a process works; they do not, by themselves, tell you which process is right for a particular production job. (ISO/ASTM 52900)
Machine manufacturers may use names for specific implementations or product families. When comparing equipment, look beyond the label to the material form, energy source, bonding mechanism and post-processing route.
Comparing the main AM process categories
The application examples below are general. Capabilities and production economics vary by machine, material and application.
Process category | Typical material forms | Common application areas | Practical limitations and production implications |
Material extrusion | Thermoplastic filament, pellets or paste | Prototypes, jigs and fixtures, housings, selected end-use polymer parts | Part properties and surface finish depend on the process, material and build orientation. Supports may be needed. Check dimensional requirements, build time and the material’s suitability for the intended environment. |
Vat photopolymerisation | Liquid photopolymer resin | Detailed models, dental and medical models, patterns, and selected functional parts | Resin properties, post-curing and exposure conditions matter. Parts may need washing and curing; suitability for long-term use depends on the specific material and application. |
Powder bed fusion | Polymer or metal powder, depending on the process | Polymer parts and metal components with complex geometry | Powder handling, build preparation, support strategy and post-processing can affect cost and throughput. Metal parts may require support removal, heat treatment, machining and inspection. |
Binder jetting | Powder with a selectively deposited liquid binder | Metal or sand parts, depending on the material system and intended use | A printed part may need a later curing, sintering or infiltration step. Account for shrinkage, final properties and the full downstream route when assessing feasibility. |
Directed energy deposition | Wire or powder fed into a focused energy source | Repair, adding features to existing parts, and larger metal builds | The deposition and finishing route must be considered together. Geometry, surface finish and final dimensions may require machining and inspection. |
Material jetting | Droplets of material, commonly photopolymers or waxes | Detailed models, patterns and parts requiring multiple material appearances | Material choices and end-use properties depend on the specific system. Consider support removal, post-processing, durability and whether the production volume suits the route. |
Sheet lamination | Sheets of material bonded in layers | Selected models, tooling and specialist applications | The bonding method, material choice and achievable geometry are process-specific. Check the resulting part’s properties and the practical steps needed to finish it. |
The category definitions follow ISO/ASTM 52900. For more on the process types, see NIST’s overview of additive manufacturing technologies.
What production maturity means in practice
It’s difficult to assign a single maturity rating to an entire AM process category. A process may be commercially available and used for production, while a particular material, machine, part or application still needs validation.
For a specific part, assess whether the proposed route has:
a defined specification and acceptance criteria
a suitable material and process combination
repeatable build preparation and process controls
the required post-processing capacity
appropriate inspection and measurement methods
enough evidence to release the part for its intended use
Qualification requirements depend on the application and industry. ISO/ASTM 52920, for example, sets requirements for industrial AM processes and production sites. It does not mean every machine or part using AM is automatically qualified.
A part can print successfully and still be a poor production candidate. The complete route - including finishing, inspection and any required evidence - matters more than whether one sample came off the machine as expected.
Metal AM is a family of processes
“Metal 3D printing” is not one technology. Powder bed fusion, directed energy deposition and binder jetting use different feedstocks and build mechanisms, so they involve different design constraints and production routes.
For example, a metal powder bed fusion part may need supports, support removal, heat treatment and machining. Directed energy deposition may be considered for adding material or repairing a component, but finishing and inspection still matter. Binder jetting uses a binder to form the part, with subsequent steps depending on the material system.
When comparing metal processes, include the full route from feedstock and build preparation through finishing and inspection. The printer’s build rate alone does not tell you how long it takes to deliver an acceptable part.
Polymer AM serves different production needs
Polymer processes range from material extrusion and vat photopolymerisation to powder bed fusion and material jetting. They can serve different purposes: a visual prototype, a production jig, a customised component or a low-volume end-use part.
The right comparison depends on the required properties and finish, part size and geometry, production quantity, and downstream work. A process suitable for detailed models may not be appropriate for parts exposed to heat, chemicals or repeated loading. Confirm those requirements against the specific material and machine data.
What’s changing in additive manufacturing?
Some developments often described as “the future of AM” are better understood as active areas of research and implementation. Their practical value depends on the process, machine, material and application.
Process monitoring and control
Monitoring systems can capture information about a build, such as melt-pool behaviour or layer characteristics. Researchers are also developing methods to use measurements as feedback for process control. That does not mean monitoring alone proves a part is acceptable or that a machine can automatically correct every defect. Measurement quality and the relationship between process signals and final part quality still matter.
AI and digital twins
Machine learning, digital twins and digital threads are being explored for applications including process assurance, production planning and qualification. NIST’s work in this area describes methods and models under development; it should not be read as evidence that every AM operation currently uses these tools or can rely on them to make production decisions autonomously.
For manufacturers, the practical questions are what data a tool uses, what it can reliably conclude, how its results are validated and who reviews decisions that affect part quality.
Materials and qualification
A growing range of material options does not automatically make a part suitable for a new application. Material properties need to be considered alongside the process, machine, build conditions, post-processing and required evidence.
For production work, ask whether the data applies to the specific material and process combination you plan to use. Material availability alone is not proof of repeatability or qualification.
Sustainability and lifecycle impact
AM can enable geometries that use less material or support local production in some situations. That does not automatically mean an AM part has a lower environmental impact. Material production, machine energy, post-processing, transport, service life and end-of-life all affect the result.
The US Department of Energy’s AM Energy Impacts Assessment tool considers lifecycle stages including materials, manufacturing, freight and distribution, use and disposal. That is a useful reminder to assess the whole product lifecycle rather than assume that localised production or reduced material use guarantees lower impact.
How to choose a process for a part
Start with the part’s requirements, then narrow the process options:
What must the part do? Define the loads, operating environment, service life and consequences of failure.
Which materials are acceptable? Check whether the process offers a suitable material and whether its documented properties match the application.
What geometry is essential? Identify internal channels, thin walls, overhangs, interfaces and features that might be difficult to build or inspect.
What finish and tolerances are required? Determine which surfaces need machining or other finishing and how critical dimensions will be measured.
How many parts are needed? Compare the complete route at the expected quantity. A low build cost per part does not automatically mean the whole production route is economical.
What downstream steps are needed? Include support removal, cleaning, curing, heat treatment, machining, inspection and any required documentation.
What evidence is required for release? For safety-critical or regulated uses, establish what material, process and part evidence is needed before production. Requirements vary by application and industry.
This helps avoid choosing a technology because it can produce the geometry, then discovering that finishing, inspection or qualification makes the overall route unsuitable.
Where hybrid manufacturing fits
Additive manufacturing can be one step in a broader production route. A component may be built additively and then machined to achieve required interfaces, dimensions or surface finish. “Hybrid manufacturing” can mean a combined route across processes; it can also refer to equipment that combines additive and subtractive operations. Be clear which meaning you are using.
The practical questions are which features will be printed, which will be machined, how the part will be located between operations, and how dimensions and revisions will be controlled. AM does not remove the need for conventional manufacturing knowledge. It changes where that knowledge is applied in the route.
For more on the combined route, see Hybrid Manufacturing: Hype or Future?. For a general explanation of subtractive methods, see What Is Subtractive Manufacturing — And Why It Still Sets the Standard for Production.
The role of digital production information
The process comparison above focuses on how parts are made. Once a manufacturer has chosen a route, production information still needs to move reliably between design, preparation, machines, post-processing and inspection.
That raises questions of revision control, build records, material identity and handovers. These concerns are not unique to one AM technology and deserve their own detailed treatment. See What Is a Digital Thread in Additive Manufacturing? for a deeper explanation.
Frequently asked questions
What are the main types of additive manufacturing?
ISO/ASTM 52900 defines seven process categories: binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, sheet lamination and vat photopolymerisation. Each category includes different implementations, materials and machine capabilities. (ISO/ASTM 52900)
Which additive manufacturing process is best?
There is no universally best process. The choice depends on the part’s material, geometry, performance requirements, quantity, finish, tolerances, post-processing and evidence requirements.
Is metal additive manufacturing ready for production?
Metal AM is used in production applications, but suitability depends on the part, process, material, production route and required evidence. A successful print alone does not establish production readiness.
Does additive manufacturing replace machining?
No. AM can complement machining, and some parts require machining after printing to meet dimensional or surface requirements. The appropriate route depends on the design and specification.
What is the difference between 3D printing and additive manufacturing?
The terms are often used interchangeably in general discussion. For technical comparison, additive manufacturing is classified into process categories such as powder bed fusion and material extrusion.
Choosing technology means choosing a production route
Additive manufacturing technologies differ in how they build parts, what materials they use and what constraints they introduce. The useful question is not simply “Can this process print the shape?” It is whether the complete route can deliver parts that meet the application’s requirements at the required quantity, quality and level of evidence.
Start with the component and its requirements. Compare plausible processes against the full production route, then test the assumptions with the machine, material and quality teams responsible for making and releasing the part.
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