Additive manufacturing and 3D printing refer to the same basic process: building objects layer by layer from a digital file. The two terms are often used interchangeably, and in casual conversation, that’s perfectly fine. But as the technology has matured into a serious industrial tool, the terms have drifted apart in how professionals use them. “Additive manufacturing” now tends to describe the broader, industrial side of the field, while “3D printing” often refers to smaller-scale or desktop applications.
Why Two Terms Exist
The technology traces back to 1986, when Charles Hull co-founded 3D Systems to commercialize stereolithography, a process he invented that uses light to harden liquid resin into solid shapes. That early technology became widely known as “3D printing,” a term that stuck with the public and media. As the technology expanded into aerospace, medicine, and large-scale manufacturing, the industry adopted “additive manufacturing” as a more formal umbrella term. The international standards body (ISO/ASTM) uses “additive manufacturing” in its official definitions, not “3D printing.”
The distinction isn’t rigid. You’ll hear engineers at Boeing say “3D printing” and hobbyists say “additive manufacturing.” But the general pattern holds: additive manufacturing signals industrial production, and 3D printing signals prototyping or smaller projects.
How the Terms Differ in Practice
Think of it as a scale difference. Additive manufacturing typically involves engineers, architects, or production managers using the technology to produce end-use parts at meaningful volumes. These are components that go into airplanes, medical devices, or machinery. In aerospace, for example, companies use additive manufacturing to produce cabin interior panels, structural brackets, and engine components that meet strict FAA regulations. One case study found that replacing aluminum brackets with additively manufactured composite parts cut weight by 50% and costs by 20%.
3D printing, by contrast, tends to describe prototyping, one-off custom parts, or desktop-scale work. Printing a small medical implant, a custom phone case, or an architectural model all fall comfortably under “3D printing.” The machines are often smaller, the materials simpler, and the stakes lower. A hobbyist with a $300 desktop printer is 3D printing. A factory producing titanium jet engine nozzles is doing additive manufacturing. Both build objects layer by layer, but the context, precision, and workflow look very different.
Seven Process Categories Under One Roof
Additive manufacturing encompasses seven standardized process categories, all of which build objects by adding material rather than cutting it away. These range from simple to highly complex:
- Material extrusion is what most desktop 3D printers use. Plastic filament is melted and squeezed through a nozzle, building up layers like a very precise hot glue gun.
- Vat photopolymerization uses a vat of liquid resin that hardens when hit by light, producing very fine details with layers as thin as 10 microns.
- Powder bed fusion spreads a thin layer of powdered metal or plastic and uses a laser or electron beam to melt it into shape. This is the workhorse of industrial metal printing.
- Material jetting works like an inkjet printer, depositing droplets of material that are cured by ultraviolet light, achieving layer thicknesses around 16 microns.
- Binder jetting sprays a liquid binding agent onto layers of powder to glue them together.
- Sheet lamination bonds sheets of metal or paper together using ultrasonic welding or adhesive, then cuts each layer to shape.
- Directed energy deposition feeds metal wire or powder into a focused energy beam, often used to repair existing parts or add material to worn components.
All seven qualify as both additive manufacturing and 3D printing in the strictest technical sense. But you’re far more likely to hear someone call powder bed fusion of titanium “additive manufacturing” than “3D printing.”
The Industrial Workflow Goes Much Further
One reason “additive manufacturing” carries a different weight is that industrial production doesn’t end when the printer stops. A desktop 3D print might need a quick sanding or a coat of paint. An industrial additive manufacturing workflow involves removing parts from powder beds, cutting supports from build platforms, heat treating metal components to relieve internal stress, and sometimes applying hot isostatic pressing (essentially using extreme heat and pressure to eliminate tiny internal voids).
After that, parts may need machining to tighten tolerances on critical surfaces, drilling and tapping for threaded holes, or coating for corrosion resistance. Quality inspection can involve coordinate measuring machines, 3D scanning, or even CT scanning to check for defects hidden inside complex internal geometries. This multi-step chain from digital file to finished, certified part is what separates additive manufacturing as an industrial discipline from 3D printing as a making tool.
Accuracy Varies Widely Across Machines
Desktop and professional machines can both produce impressively detailed parts, but the tolerances they achieve differ. In one study comparing dental printers, three different machines produced parts with average dimensional errors between 65 and 80 microns, roughly the width of a human hair. A separate study comparing material extrusion (the most common desktop technology) to material jetting found mean deviations of 47 microns and 38 microns respectively.
For context, dental restorations generally require accuracy within 100 to 150 microns to fit properly. Industrial metal additive manufacturing can hit similar or tighter tolerances, but often relies on post-processing machining to get there. The raw accuracy of the printing step is only part of the story in a production environment.
A Growing Industry Under Either Name
Regardless of what you call it, the market is expanding fast. The global additive manufacturing market is valued at roughly $26 billion in 2025 and is projected to reach about $126 billion by 2034, growing at nearly 20% per year. That growth is driven heavily by industrial adoption: aerospace, medical devices, automotive, and on-demand spare parts. Companies are shifting from using the technology purely for prototyping to producing final parts at scale, which is exactly the shift that has made “additive manufacturing” the preferred professional term.
For most everyday purposes, calling it 3D printing is perfectly clear and accurate. If you’re talking about industrial production, supply chains, or engineering applications, additive manufacturing is the term that signals you mean serious, production-grade work. They describe the same fundamental technology, just at different levels of scale and intent.