3D printing builds a physical object from a digital model by adding material one thin layer at a time. UltiMaker defines it as a manufacturing process that creates an object from a digital file, which is why the same technology is also called additive manufacturing. It is the reverse of machining, where you start with a solid block and cut material away until the part is left.
The term covers very different machines. A desktop printer that melts plastic filament, a resin printer that hardens liquid with light, and an industrial system that melts metal powder with a laser are all 3D printers. Standards bodies sort them into seven process families. Knowing which family a machine belongs to tells you a lot about the materials it can use, the parts it can make and the work that follows each print.
From file to part
- Create or download a 3D model, usually in CAD software or from a 3D scan, and export it as a mesh file such as STL, OBJ or 3MF.
- Open the file in slicing software, which orients the part, adds supports where needed and cuts the model into thin horizontal layers.
- The slicer writes machine instructions, G-code for most filament printers, that describe where material goes in every layer.
- The printer builds the part one layer at a time, moving the platform by one layer thickness after each layer.
- Remove the part and post-process it: take off supports, wash and cure resin, clear away unused powder, or sinter and machine metal parts.
- Check the part for fit, strength and appearance, then adjust the design or settings for the next print.
Additive versus subtractive manufacturing
Conventional metal parts often start as a billet, rod or plate that machine tools mill and drill down to shape. Desktop Metal's binder jetting guide notes that buy-to-fly ratios of about 10 to 1 are common in aerospace, which means roughly 90 percent of the purchased metal is cut away. Additive manufacturing places material only where the part needs it, layer by layer, directly from a digital file, without molds or fixtures specific to the part.
Building in layers also changes which shapes are practical. Internal channels, lattices and assemblies printed as a single piece become possible without tooling. NIST's 2014 cost report notes that the technology can produce strong, lightweight aerospace parts and allows designs that earlier methods could not make. The trade-off is that every process has its own limits on materials, accuracy, surface finish and speed, so 3D printing usually complements machining, molding and casting rather than replacing them.
The idea is older than most people expect. UltiMaker says the process was devised in the 1980s, when it was known as rapid prototyping. Formlabs credits Hideo Kodama with early layered photopolymer work in the early 1980s and Charles Hull with patenting stereolithography in 1986.
The seven process families
ASTM International's F42 committee developed the terminology that sorts additive manufacturing into seven process categories. The current joint standard, ISO/ASTM 52900:2021, keeps the seven categories and gives each a short abbreviation. NIST's 2014 report points out that many companies created their own system and material names to stand out, which makes the field look more varied than it really is. The family name tells you how material is joined, whatever the brand calls it.
Some processes sit near a boundary. HP describes its Multi Jet Fusion as combining elements of powder bed fusion and binder jetting, but it fuses polymer powder with heat rather than gluing it, so it is usually discussed with powder bed fusion. The table lists each family with the familiar names you will see on machines and in service catalogs.
| Family (abbreviation) | How a layer is made | Familiar names | Typical materials |
|---|---|---|---|
| Material extrusion (MEX) | Material is pushed through a nozzle along a path | FDM, FFF | Thermoplastic filament, composites |
| Vat photopolymerization (VPP) | Light cures liquid resin held in a vat | SLA, DLP, MSLA or LCD | Photopolymer resins |
| Powder bed fusion (PBF) | A laser, electron beam or heat fuses areas of a powder bed | SLS, MJF, DMLS, SLM, LPBF, EBM | Nylon and other polymers, metals |
| Binder jetting (BJT) | A printhead deposits liquid binder into a powder bed | Binder jet, 3DP, Metal Jet | Sand, metals, ceramics |
| Material jetting (MJT) | A printhead deposits droplets of build material | PolyJet, MultiJet (MJP) | Photopolymers, waxes |
| Directed energy deposition (DED) | Focused energy melts material as it is deposited | LENS, EBAM, WAAM | Metal powder or wire |
| Sheet lamination (SHL) | Sheets are bonded and cut to the layer outline | LOM, UAM | Paper, metal foil |
Desktop and industrial machines
Most people first meet 3D printing through desktop machines. Filament printers are the cheapest to buy and run: UltiMaker describes FFF as typically lower cost than other processes and easy to use, with build volumes from about 10 cm up to about 1 m per side on the largest units. Desktop resin printers trade a messier workflow for finer detail. Formlabs puts low-cost LCD resin printers at about $200 to $1,000 and professional resin printers at about $2,500 to $10,000.
Industrial machines are a different class of investment. Formlabs, which sells smaller SLS systems, estimates traditional industrial SLS printers at $200,000 to $500,000 or more, with specialized HVAC, power and a trained operator. Prusa notes that even the cheapest SLS machines start at around $6,000. Metal powder bed fusion adds inert gas or vacuum, careful powder handling and heat treatment, so most people buy metal parts from a service before they consider owning a machine.
Where 3D printing is used
Prototyping is still the most common use. Designers print concept models to check shape and fit, and engineers print functional prototypes to test. UltiMaker lists rapid tooling, replacement parts, end-use parts and small first production runs alongside prototyping and education. Formlabs lists jigs and fixtures, casting patterns, dental models, surgical guides and custom hearing products among common resin applications.
Production use is growing where complexity or customization pays for itself. EOS names aerospace, automotive, medical, tooling and turbomachinery as the main applications of its metal process. Colibrium Additive, a GE Aerospace company, says some of its electron beam systems routinely print more than 150 acetabular cups for hip implants in a single run. Cranfield University's wire arc research targets large aerospace structures, and UltiMaker notes that very large machines are being developed to print concrete for construction.
What limits a printed part
Layers give parts a direction. UltiMaker lists visible layer lines and weaker strength along the Z axis among the limits of filament printing, so the way you orient a part on the plate affects how strong it is. Resin parts have smoother surfaces but need washing and post-curing. Powder parts come out slightly grainy and usually get blasted. Nearly every process needs some post-processing, and for metal parts that often includes stress relief, support removal and finish machining.
Overhangs and speed are the other constraints. Filament and resin parts need supports under overhangs, while in SLS, MJF and binder jetting the loose powder holds the part up, as HP and Formlabs both note. A laser that traces each layer takes longer as you add parts. Processes that expose or print a whole layer at once, such as DLP, MSLA, MJF and binder jetting, spend about the same time per layer however many parts share the build, according to Prusa, TI, HP and Desktop Metal.
How to get started
If you want to learn by doing, a filament printer is the usual first machine. UltiMaker recommends PLA as the beginner filament and calls PETG another beginner-friendly option. Start with a tested model and the printer maker's recommended slicer profile, print something small, and only then begin designing your own parts.
Choose resin when fine detail and smooth surfaces matter more than convenience, for example miniatures, jewelry patterns or dental models. Plan for a wash and cure step and a ventilated workspace: Prusa advises avoiding skin contact with liquid resin and not inhaling its vapors. For nylon or metal parts, ordering from a service bureau is a practical first step that lets you judge SLS, MJF or metal printing on real parts before you consider buying equipment.
At a glance
Strengths
- Makes complex shapes, internal channels and one-piece assemblies without tooling
- A design change needs a new file, not a new mold
- Well suited to prototypes, custom parts and low volumes
- Wide range of processes and materials, from PLA to titanium
Limitations
- Layer lines and direction-dependent strength in many processes
- Post-processing is almost always needed
- Molding is usually more economical at high volumes
- Each process works with a limited set of materials
Typical applications
- Prototypes and concept models
- Jigs, fixtures and tooling
- Dental and medical devices
- Aerospace and industrial end-use parts
- Education and hobby projects
Materials for this process
Common questions
Is 3D printing the same as additive manufacturing?
In practice, yes. Desktop Metal notes that additive manufacturing is the formal industry term and 3D printing the more common one, and the two are used interchangeably. Some people reserve additive manufacturing for industrial production, but both describe building a part layer by layer from a digital model.
Which type of 3D printer should a beginner buy?
Most beginners start with a filament (FFF) printer because it is the cheapest to buy and run and the easiest to learn. Choose a resin printer instead if your main goal is small, highly detailed parts and you are prepared for the washing, curing and safety precautions that come with liquid resin.
Can 3D printers make metal parts?
Yes, but mostly on industrial machines. Laser and electron beam powder bed fusion, binder jetting followed by furnace sintering, and directed energy deposition all produce metal parts. Each needs controlled atmospheres, powder or wire handling and post-processing, which is why many people order metal parts from a service.
How long does a 3D print take?
It depends on the process, part size and how many parts share the build. Formlabs says most Form 4 resin builds finish in under two hours, while it gives roughly 15 to 24 hours for full builds on its smaller SLS printers, plus cooling time. Large filament parts can run overnight or longer.
Sources
- What is 3D printing? UltiMaker · Checked 2026-11-02
- What is FFF 3D printing? UltiMaker · Checked 2026-11-02
- FDM vs FFF: Understanding 3D Printing Technologies UltiMaker · Checked 2026-11-02
- A Comprehensive Overview of Additive Manufacturing Processes Through a Time-Based Classification Model (Koltsaki and Mavri, 2024) 3D Printing and Additive Manufacturing, via PubMed Central · Checked 2026-11-02
- Costs and Cost Effectiveness of Additive Manufacturing (process definitions, section 2.1) NIST · Checked 2026-10-15
- Additive Manufacturing Technologies NIST · Checked 2026-10-15
- The 7 categories of Additive Manufacturing Loughborough University Additive Manufacturing Research Group · Checked 2026-11-02
- Introduction to 3D printing processes HP · Checked 2026-11-02
- Comparing Binder jetting, Material Jetting, Multi Jet Fusion and SLS HP · Checked 2026-11-02
- Guide to Resin 3D Printers: SLA vs. DLP vs. MSLA vs. LCD Formlabs · Checked 2026-11-02
- Guide to Stereolithography (SLA) 3D Printing Formlabs · Checked 2026-10-15
- Selective Laser Sintering (SLS): Complete Guide Formlabs · Checked 2026-10-15
- Types of printers and their differences Prusa Research · Checked 2026-11-02
- TI DLP Technology for 3D Printing (DLPT019F, revised August 2025) Texas Instruments · Checked 2026-11-02
- The Ultimate Guide to Laser-Free Metal 3D Printing (binder jetting) Desktop Metal · Checked 2026-11-02
- DMLS Metal 3D Printing EOS · Checked 2026-11-02
- Enabling Metal Additive Production Using Electron Beam Melting Technology (EBM Anthology) Colibrium Additive · Checked 2026-11-02
- Printing the future: WAAMMat case study Cranfield University · Checked 2026-11-02
- Material Extrusion Loughborough University Additive Manufacturing Research Group · Checked 2026-11-02
An explainer synthesized from the cited references, not hands-on testing. Vendor names for processes are trademarks of their owners and are mapped to the ISO/ASTM 52900 families for orientation.