What is 3D printing?
3D printing is a manufacturing process that creates three-dimensional objects by adding material layer by layer from a digital 3D model.
Unlike subtractive manufacturing, which removes material from a solid block, or formative manufacturing, which shapes material using molds or dies, additive manufacturing builds only the material needed to form the final part.
Every 3D printing process follows the same core principle: a digital model is transformed into a physical object, by building successive layers of material, until the complete part is formed.
How Does 3D Printing Work?
Although the specific method varies between different 3D printing processes, they all follow the same fundamental workflow:
- Create a 3D Model
A three-dimensional digital model is created using Computer-Aided Design (CAD) software, generated through 3D scanning, or obtained from an existing digital file. - Prepare the Model
The model is exported into a 3D printing file format (such as STL, 3MF, or AMF) and imported into slicing software, which converts the model into hundreds or thousands of horizontal layers and generates the machine instructions (typically G-code or a machine-specific build file). - Set Up the Printer
The appropriate material is loaded, the build platform is prepared, and the required print parameters, (such as layer height, print speed, temperature, laser power, or exposure time), are configured according to the selected printing process. - Print the Part
The printer manufactures the object by building it one layer at a time. Depending on the process, material may be extruded through a nozzle, cured using ultraviolet light, fused from a powder bed, jetted as droplets, deposited into a melt pool, or bonded from thin sheets. - Post-Process the Part
Once printing is complete, the part may require post-processing such as support removal, washing, curing, sintering, infiltration, heat treatment, machining, sanding, polishing, or surface finishing to achieve its final dimensions, mechanical properties, and appearance. - Inspect and Use the Part
The finished component is inspected to verify dimensional accuracy and quality before being used as a prototype, tooling, or a functional end-use part.
difference between 3D printing & additive manufacturing?
The terms are often used interchangeably, but there is a subtle distinction:
- 3D printing = usually refers to the specific process of creating a three-dimensional object by depositing or solidifying material layer by layer from a digital model.
The term originated with consumer and desktop printers and is commonly used in hobbyist, educational, and prototyping contexts. - Additive manufacturing (AM) = is the broader industrial term for all manufacturing processes that build parts by adding material layer by layer.
It encompasses 3D printing technologies but also includes the engineering, quality control, materials science, and production workflows needed for manufacturing end-use parts.
Materials For 3D Printing
3D printing can produce components from a wide range of materials, including:
- Plastics
- Metals
- Ceramics
- Composites
- Concrete
- Biomaterials
- Food-grade materials.
Depending on the technology used, these materials may be extruded, cured with light, fused from powder, jetted as droplets, deposited using directed energy, or bonded from sheets, and more.
The 7 Groups of additive manufacturing, Defined by ASTM & ISO
The ASTM/ISO standards defined 7 main process groups of additive manufacturing.
These standardized groups are:
- Material Extrusion: Melts and deposits material through a nozzle, layer by layer.
- Vat Photopolymerization: Uses light to cure liquid resin into solid layers.
- Powder Bed Fusion: Uses a laser or other energy source to fuse powder particles.
- Binder Jetting: Deposits a liquid binder onto a powder bed to join particles.
- Material Jetting: Jets droplets of build material and cures them.
- Directed Energy Deposition (DED): Feeds material (wire or powder) into a focused energy source that melts it during deposition.
- Sheet Lamination: Bonds sheets of material together and cuts them into shape.
A Dive Into The Standardized Groups Of Additive Manufacturing
& Their 3D Printing Processes
There are dozens of other 3D printing processes. And these processes are part of the 7 main process groups of additive manufacturing:
1. Material Extrusion
❝Material is selectively dispensed through a nozzle or orifice, to build parts layer by layer.❞
Fused Deposition Modeling (FDM) = Fused Filament Fabrication (FFF)
A continuous thermoplastic filament is fed into a heated nozzle, where it is melted and deposited layer by layer to build a part. The material solidifies as it cools, bonding to previously deposited layers.
Note!
FDM and FFF refer technically to the same 3D printing process. The difference is primarily commercial (due to legal trademarks).
Fused Granulate Fabrication (FGF)
Thermoplastic pellets or granules are melted and extruded through a nozzle, instead of filament.
This process enables higher deposition rates and lower material costs, making it particularly suitable for large-format printing.
Direct Ink Writing (DIW)
A viscous material such as an ink, paste, gel, or slurry is extruded through a nozzle to create three-dimensional structures. The deposited material is subsequently solidified through drying, curing, cooling, or chemical reactions, depending on the material system.
Robocasting
A ceramic-specific form of Direct Ink Writing that extrudes concentrated ceramic paste to produce a part.
The printed component is then dried, debound, and sintered to achieve its final density and mechanical properties.
Extrusion-Based Bioprinting
Bioinks containing living cells and biomaterials are extruded through a nozzle to fabricate tissue-like structures. The process is designed to maintain cell viability while precisely depositing biological materials.
2. Vat Photopolymerization
❝Liquid photopolymer resin is selectively cured, using light.❞
Note!
The word “vat” simply means a large container or tank used to hold a liquid.
In vat photopolymerization, the vat is the container that holds the liquid photopolymer resin during the printing process.
Stereolithography (SLA)
A vat of liquid photopolymer resin is selectively cured using a focused ultraviolet laser.
Each cured layer adheres to the previous one, gradually forming the final part.
Digital Light Processing (DLP)
An entire layer of photopolymer resin is cured simultaneously using a projected digital light image. Because complete layers are exposed at once, DLP generally offers faster print speeds than laser-based SLA.
Masked Stereolithography (MSLA/LCD)
An LCD screen acts as a mask, selectively allowing ultraviolet light to cure an entire resin layer simultaneously.
This process combines high resolution with relatively low equipment cost.
Note!
LCD means this: Liquid Crystal Display.
It is a flat-panel display technology that uses liquid crystal molecules to control how much light passes through each pixel.
Continuous Liquid Interface Production (CLIP)
A continuous build process that maintains a persistent liquid interface between the cured part and the resin using an oxygen-permeable window. This eliminates the traditional layer-by-layer stop-and-start motion, enabling significantly faster printing.
Two-Photon Polymerization (2PP)
An ultrafast laser induces polymerization only at the precise focal point through simultaneous absorption of two photons.
This enables the fabrication of extremely complex microstructures with sub-micron resolution!
Projection Micro-Stereolithography (PµSL)
A high-resolution photopolymerization process that projects microscopic images into resin to produce miniature components with extremely fine feature detail. It is widely used in microfabrication and precision engineering.
Volumetric Additive Manufacturing (VAM)
Light patterns are projected into a rotating volume of photopolymer resin, curing the object throughout its entire volume rather than layer by layer. This emerging process enables extremely rapid fabrication of complex geometries!
3. Powder Bed Fusion
❝Thermal energy selectively fuses material within a powder bed.❞
Selective Laser Sintering (SLS)
A laser selectively sinters thermoplastic powder particles together without fully melting them.
After each layer is completed, a fresh layer of powder is spread across the build platform!
High-Speed Sintering (HSS)
An infrared-absorbing agent is selectively deposited onto the powder bed before infrared energy fuses the marked regions. The process is designed for higher production throughput than conventional SLS.
Selective Absorption Fusion (SAF)
A radiation-absorbing fluid is selectively printed onto a powder bed before infrared energy fuses the coated regions. Uniform thermal control helps produce consistent mechanical properties across the build volume.
Electron Beam Powder Bed Fusion (EB-PBF)
An electron beam selectively melts conductive metal powder inside a high-vacuum chamber. The elevated build temperature reduces residual stresses and makes the process well suited for reactive alloys such as titanium.
Laser Powder Bed Fusion (LPBF)
A high-power laser selectively melts metal powder to produce fully dense components with complex geometries. It is one of the most widely used metal additive manufacturing processes in industry.
Laser Sintering of Ceramics
A laser selectively fuses ceramic powder to create ceramic components. Due to the material properties of ceramics, additional post-processing such as infiltration or sintering is often required.
4. Binder Jetting
❝A liquid binder selectively joins powder particles.❞
Metal Binder Jetting
A liquid binder is selectively deposited onto a bed of metal powder to form a green part. The printed component is subsequently cured, debound, and sintered to achieve its final density.
Note!
A green part (or green body) is a part that has its final shape but has not yet been fully densified or strengthened.
A green part is typically porous and fragile. Therefore, it needs posterior processing, such as curing and sintering.
Ceramic Binder Jetting
A binder selectively joins ceramic powder particles to create a green body. The component is later sintered to develop its final strength and density.
Sand Binder Jetting
A binder is selectively deposited onto sand to produce molds and cores for metal casting. This process eliminates the need for traditional tooling and enables rapid production of complex foundry components.
Polymer Binder Jetting
A liquid binder selectively joins polymer powder particles to form the printed object. The resulting component may require infiltration or additional post-processing depending on the material system.
5. Material Jetting
❝Droplets of build material are selectively deposited and cured.❞
Material Jetting
Droplets of liquid photopolymer are precisely deposited through inkjet printheads and immediately cured using ultraviolet light. The process produces parts with excellent surface finish and high dimensional accuracy.
Multi-Material Jetting
Multiple photopolymers are jetted simultaneously, allowing different colors, transparencies, and mechanical properties to be combined within a single printed part. This enables highly realistic prototypes and functional assemblies.
Wax Jetting
Molten wax droplets are deposited layer by layer to produce highly detailed patterns. These patterns are commonly used for investment casting in jewelry, dental, and precision manufacturing applications.
Nanoparticle Jetting
A liquid suspension containing metal or ceramic nanoparticles is jetted onto the build platform. After printing, the carrier liquid is removed and the part is sintered to produce a dense component.
6. Directed Energy Deposition (DED)
❝Focused thermal energy melts material as it is deposited.❞
Laser Metal Deposition (LMD)
Metal powder is delivered into a laser-generated melt pool, where it is fused onto the substrate as material is deposited. The process is widely used for component repair, feature addition, and near-net-shape manufacturing.
Wire Arc Additive Manufacturing (WAAM)
Metal wire is melted using an electric arc and deposited layer by layer. Its high deposition rate makes it particularly suitable for manufacturing large metal components.
Electron Beam Additive Manufacturing (EBAM)
Metal wire is melted using a focused electron beam inside a vacuum chamber. The process enables high deposition rates while producing components with low contamination and excellent material quality.
Laser Wire Deposition
Metal wire is continuously fed into a laser-generated melt pool, where it is fused to build the component. Compared with powder-fed systems, wire feedstock typically offers higher material utilization.
Cold Spray Additive Manufacturing (CSAM)
Metal particles are accelerated to supersonic velocities and bond to the substrate through solid-state plastic deformation without melting. Because no melting occurs, oxidation, thermal distortion, and residual stresses are significantly reduced.
7. Sheet Lamination
❝Sheets of material are bonded together to form a part.❞
Laminated Object Manufacturing (LOM)
Sheets of material are bonded together using adhesive before each layer is cut to shape. Successive layers form the finished part, while excess material provides support during printing.
Ultrasonic Additive Manufacturing (UAM)
Thin metal foils are joined using ultrasonic vibrations under pressure without melting the material. The resulting solid-state bond minimizes thermal distortion and allows dissimilar metals to be combined.
Selective Deposition Lamination (SDL)
Sheets of paper are selectively bonded together with adhesive before being cut to shape. The process produces inexpensive full-color models with a wood-like appearance.
Metal Foil Lamination
Thin metal sheets are stacked and bonded using diffusion bonding, brazing, welding, or similar joining methods before machining defines the final geometry. The process is primarily used for specialized metal applications.
Polymer Sheet Lamination
Polymer sheets are bonded together sequentially to build three-dimensional components. The process is less common than extrusion or powder-based methods but can efficiently produce specific polymer structures.
When to use which 3D printing process?
There is no single 3D printing process that is best for every application.
The appropriate process depends on the part’s requirements, including its:
- Material compatibility (plastics, metals, ceramics, composites, biomaterials, etc.)
- Mechanical properties (strength, stiffness, toughness, heat resistance)
- Part size
- Dimensional accuracy + tolerances
- Surface finish
- Production quantity (prototype, low-volume, or mass production)
- Cost of material & manufacturing
- Intended use
- Post-processing requirements
The following table provides a rough guideline to learn how to choose a 3D printing process:
| Process | Best Materials | Best For | Cost | Accuracy | Surface Finish | Strength | Speed |
|---|---|---|---|---|---|---|---|
| Material Extrusion | Thermoplastics | • Low-cost prototypes • Functional parts | 🟢 | 🔴 | 🔴 | 🟡 | 🟡 |
| Vat Photopolymerization | Photopolymer resins | • High-detail models • Smooth surfaces | 🟡 | 🟢 | 🟢 | 🟡 | 🟡 |
| Powder Bed Fusion | Polymers, metals | • Functional end-use parts | 🔴 | 🟢 | 🟡 | 🟢 | 🟡 |
| Binder Jetting | Metals, ceramics, sand | • High-volume production • Casting molds | 🟡 | 🟡 | 🟡 | 🟡* | 🟢 |
| Material Jetting | Photopolymers | • Multi-material and full-color parts | 🔴 | 🟢 | 🟢 | 🟡 | 🟡 |
| Directed Energy Deposition (DED) | Metals | • Large metal parts • Repair • Feature addition | 🔴 | 🔴 | 🔴 | 🟢 | 🟢 |
| Sheet Lamination | Paper, metal sheets | • Concept models • Laminated metal components | 🟢 | 🔴 | 🔴 | 🔴 | 🟢 |
*Metal binder-jetted parts achieve their final mechanical properties after post-processing, such as sintering.
Note!
- Cost: 🟢 = Lower cost • 🟡 = Medium cost • 🔴 = Higher cost
- All other attributes: 🟢 = High / Very High • 🟡 = Medium • 🔴 = Low / Fair
Industry & Real-Life Applications of 3D Printing
3D printing is used across a wide range of industries to create prototypes, tooling, customized products, and end-use parts.
Some of the most common applications include:
- Aerospace – Lightweight components, aircraft parts, and engine components.
- Automotive – Prototypes, production tools, spare parts, and custom components.
- Healthcare & Medical – Prosthetics, implants, surgical guides, anatomical models, and medical devices.
- Dentistry – Crowns, bridges, aligners, dentures, and dental models.
- Architecture & Construction – Scale models, building components, and 3D-printed structures.
- Manufacturing – Jigs, fixtures, tooling, molds, and production parts.
- Education & Research – Teaching models, scientific research, and rapid prototyping.
An Overview: 3D Printing Processes
| Additive Manufacturing Group | 3D Printing Processes |
|---|---|
| 1. Material Extrusion | • Fused Deposition Modeling (FDM) / Fused Filament Fabrication (FFF) • Fused Granulate Fabrication (FGF) • Direct Ink Writing (DIW) • Robocasting • Extrusion-Based Bioprinting |
| 2. Vat Photopolymerization | • Stereolithography (SLA) • Digital Light Processing (DLP) • Masked Stereolithography (MSLA/LCD) • Continuous Liquid Interface Production (CLIP) • Two-Photon Polymerization (2PP) • Projection Micro-Stereolithography (PµSL) • Volumetric Additive Manufacturing (VAM) |
| 3. Powder Bed Fusion | • Selective Laser Sintering (SLS) • High-Speed Sintering (HSS) • Selective Absorption Fusion (SAF) • Laser Powder Bed Fusion (LPBF) • Electron Beam Powder Bed Fusion (EB-PBF) • Laser Sintering of Ceramics |
| 4. Binder Jetting | • Metal Binder Jetting • Ceramic Binder Jetting • Sand Binder Jetting • Polymer Binder Jetting |
| 5. Material Jetting | • Material Jetting • Multi-Material Jetting • Wax Jetting • Nanoparticle Jetting • Material Jetting Bioprinting |
| 6. Directed Energy Deposition (DED) | • Laser Metal Deposition (LMD) • Wire Arc Additive Manufacturing (WAAM) • Electron Beam Additive Manufacturing (EBAM) • Laser Wire Deposition • Plasma Arc Deposition • Cold Spray Additive Manufacturing (CSAM) |
| 7. Sheet Lamination | • Laminated Object Manufacturing (LOM) • Ultrasonic Additive Manufacturing (UAM) • Selective Deposition Lamination (SDL) • Metal Foil Lamination • Polymer Sheet Lamination |
Note!
This table lists the generic 3D printing processes. It intentionally excludes proprietary and trademarked technologies (e.g., PolyJet®, Multi Jet Fusion®, Digital Light Synthesis®) to avoid duplication and maintain a vendor-neutral classification.
Making 3D Printing More Sustainable…
While 3D printing can reduce material waste and enable more efficient designs, it is not inherently more sustainable than conventional manufacturing.
Its sustainability impact depends on the printing process, material, energy consumption, post-processing, and the product’s entire life cycle.
For example, these are the current sustainability challenges of 3D printing:
- High energy consumption, particularly for metal additive manufacturing.
- Limited recyclability of some materials, such as photopolymer resins and composites.
- Material waste from support structures and failed prints.
- Energy-intensive post-processing, including curing, machining, and heat treatment.
- Limited use of recycled materials in many industrial applications.
However, the additive manufacturing industry is improving sustainability through:
- Recycled and bio-based materials to reduce environmental impact.
- Topology optimization and lattice structures to minimize material use while maintaining strength.
- More energy-efficient printers and faster manufacturing processes.
- Reduced support material through improved software and process optimization.
- On-demand and localized manufacturing, reducing transportation, warehousing, and overproduction.
- Repair and remanufacturing, extending the lifespan of high-value components instead of replacing them.
Conclusion
- There is no universally “best” 3D printing process. By understanding the strengths and trade-offs of each 3D printing process, you can confidently select the most appropriate additive manufacturing technology for your needs.
- The right choice depends on the application’s specific requirements, including material, geometry, mechanical properties, accuracy, surface finish, production volume, cost, and more!
