Independent metal AM
How metal 3D printers work — the major technologies explained simply
Metal 3D printers do not all work the same way. Some melt thin layers of metal powder with lasers. Some print binder into powder and use a furnace afterward. Others feed metal wire or powder directly into a heat source.
The process you choose changes the machines you should compare, the materials you can use, the size and geometry of the parts you can make, the post-processing required and the economics of ownership.
The 30-second overview
Laser powder bed fusion (LPBF)
Spreads a thin layer of metal powder and selectively melts each cross-section with one or more lasers.
Think of it like: Drawing each slice of the part with a laser, one powder layer at a time.
Binder jetting
A printhead selectively deposits binder into a metal-powder bed. The printed “green” part is then debound and sintered.
Think of it like: Printing with glue into metal powder, then baking the part into dense metal.
Directed energy deposition (DED)
Metal powder or wire is delivered directly into a focused energy source, creating a melt pool and depositing material where it is needed.
Think of it like: A highly controlled automated welding/deposition process.
WAAM (wire-arc additive manufacturing)
Metal wire is melted by an electric arc and deposited layer by layer, usually using robotic or gantry motion.
Think of it like: Robotic welding used to build up an entire large metal shape.
Cold spray
Metal particles are accelerated to very high velocity and bond to a surface primarily through impact rather than conventional melting.
Think of it like: Blasting metal particles fast enough that they consolidate onto the part.
Bound-metal extrusion
A printer deposits feedstock containing metal powder held in a binder. The printed part is later debound and sintered.
Think of it like: Plastic-style extrusion printing, followed by furnace processing that turns the part into metal.
Laser powder bed fusion (LPBF)
In plain English
A thin layer of metal powder is spread across a build plate. A laser selectively melts the part’s cross-section into that layer. The plate lowers, fresh powder is spread, and the laser repeats — until the part is complete, buried in powder.
What happens step by step
What makes it different
Each cross-section is fused within a surrounding powder bed. Depending on geometry, orientation, material and thermal behavior, many LPBF parts still require designed support structures for anchoring, heat control or overhangs. LPBF is also the most established metal powder-bed family: eighteen machines in our library are LPBF systems. The names DMLS and SLM describe the same family — see our naming explainer.
Where buyers commonly investigate it
Fine, complex parts in alloys such as titanium, stainless steel and nickel superalloys, where a fusion-based powder-bed process and high-density parts are required. Browse the machine library or read LPBF vs DMLS vs SLM.
Things to verify before you commit
- Material qualification status for your exact alloy and lot.
- Published build envelope versus usable space after supports and recoating clearance.
- Laser configuration and how the OEM states productivity.
- Support strategy and removal effort.
- Atmosphere and infrastructure: inert gas, filtration, floor space.
Binder jetting
In plain English
A printhead deposits a liquid binder into a bed of metal powder, gluing particles together layer by layer. The printed part — called a green part — is fragile. A furnace cycle afterwards turns it into dense metal.
What happens step by step
What makes it different
The printer and the metallurgy are separated. Printing can be comparatively rapid because the printhead deposits binder rather than melting each cross-section with a focused energy source; the furnace step is where density is achieved. That split changes the workflow, the cost structure and the supply chain compared with LPBF.
Where buyers commonly investigate it
Batches of smaller parts, complex geometries without support structures, and buyers who can access debinding and sintering — in-house or through a partner. Library examples: HP Metal Jet S100 and Desktop Metal Shop System. Compare it with LPBF in LPBF vs binder jetting.
Things to verify before you commit
- Sinter shrinkage and distortion for your geometry.
- Debinding and sintering equipment or partner route.
- Alloy portfolio and density targets.
- Green-part handling and strength.
- Post-sinter finishing allowance.
Directed energy deposition (DED)
In plain English
Metal powder or wire is fed directly into a focused heat source — laser, electron beam or arc — creating a melt pool that solidifies into deposited material. The deposition head moves, tracing beads that build up a feature or a whole part.
What happens step by step
What makes it different
Deposition happens at the point of use, not inside a buried powder bed. That is why DED is commonly investigated for repair, adding material to existing components and building larger near-net shapes.
Where buyers commonly investigate it
Repair and feature addition, larger components, and material addition where the substrate matters. Library examples: Sciaky EBAM 300 (electron-beam wire DED) and Meltio M600 (laser wire DED). Read LPBF vs DED.
Things to verify before you commit
- Deposition rate versus surface quality for your geometry.
- Machining allowance on deposited material.
- Residual stress and distortion management.
- Atmosphere: chamber versus local shielding.
- Qualification route for repairs.
WAAM (wire-arc additive manufacturing)
In plain English
WAAM feeds metal wire into an electric arc and builds the part bead by bead with robotic or gantry motion — automated welding scaled up to entire structures.
What happens step by step
What makes it different
Scale. WAAM trades fine detail for deposition volume, and it sits inside the wire-arc branch of the DED landscape: not every DED system is WAAM, and not every wire system is WAAM.
Where buyers commonly investigate it
Very large components and structural geometries where finishing will follow regardless. Library example: WAAM3D MiniWAAM (wire-arc DED). The library also carries Sciaky EBAM 300, a related electron-beam wire-fed approach with a different heat source.
Things to verify before you commit
- Residual stress and distortion management across large builds.
- Inter-layer machining and inspection plan.
- Qualified wire supply for your alloy.
- Build-room footprint, safety and fume extraction.
- Finishing budget after deposition.
Cold spray
In plain English
Cold spray accelerates metal powder in a heated gas stream to supersonic speed. Particles strike the substrate so hard that they bond — largely without a conventional melt pool.
What happens step by step
What makes it different
Solid-state deposition. Because there is no conventional melting, cold spray is commonly investigated where heat input must be limited — coatings, repair and additive builds on heat-sensitive substrates.
Where buyers commonly investigate it
Coatings, dimensional repair, corrosion protection and additive builds on heat-sensitive parts. Library example: SPEE3D LightSPEE3D.
Things to verify before you commit
- Bond strength and the qualification route for your application.
- Deposit density and porosity.
- Substrate preparation.
- Allowable deposit thickness.
- Alloy compatibility.
Bound-metal extrusion
In plain English
Bound-metal extrusion works like a metal version of FDM printing: feedstock — metal powder held in a binder — is extruded through a nozzle layer by layer. Debinding and sintering afterwards turn the green part into dense metal.
What happens step by step
What makes it different
Like binder jetting, the printer and the metallurgy are separated — but one selectively binds a powder bed while the other deposits bound feedstock through an extrusion-style process. That changes part geometry, support strategy and workflow.
Where buyers commonly investigate it
Small-to-medium batches and shop-floor workflows where a furnace route is acceptable. Library examples: Markforged Metal X and Desktop Metal Studio.
Things to verify before you commit
- Shrinkage and distortion through debind and sinter.
- The debind/sinter route: in-house or partner.
- Alloy portfolio and density targets.
- Build throughput and batch size.
- Support and post-sinter finishing.
The families side by side
| Aspect | LPBF | Binder jetting | DED | WAAM | Cold spray | Bound-metal extrusion |
|---|---|---|---|---|---|---|
| Starting material | Powder | Powder | Powder and/or wire, depending on system | Wire | Powder | Bound feedstock (filament or rod, depending on system) |
| Metal melted during printing? | Yes | No | Yes | Yes | Generally no conventional melting | No |
| Furnace afterward? | Not a process requirement; post-processing still common | Typically yes — debind and sinter | Not a process requirement; post-processing still common | Not a process requirement; post-processing still common | Not a process requirement; post-processing still common | Typically yes — debind and sinter |
| Geometric detail | Commonly investigated for fine, complex features | Detail is possible; sintering distortion is a design factor | Deposited material typically needs finishing for fine detail | Large, simpler geometries; finishing usually required | Coating- and surface-scale deposition | Extrusion-style resolution; sintering distortion is a design factor |
| Large-part suitability | Envelope-bound; large-format machines exist | Envelope-bound | Commonly investigated for larger components | Commonly investigated for very large structures | Commonly investigated for surface-scale addition | Envelope-bound |
| Repair / adding material | Not the common investigation path | Not commonly investigated for repair | Commonly investigated for repair and material addition | Commonly investigated for large-scale repair and addition | Commonly investigated for coating and repair | Not commonly investigated for repair |
| Primary distinction | Melts powder in a bed, layer by layer | Binds powder in a bed; furnace consolidation | Feeds powder or wire into a melt pool at the point of deposition | Wire-arc deposition at structural scale | High-velocity particle bonding without conventional melting | Extrudes bound feedstock; furnace consolidation |
Which process should I investigate?
If your starting question is…
- “I need fine, complex parts from metal powder” → investigate LPBF.
- “I want to print many parts and can support debinding/sintering” → investigate binder jetting.
- “I need to add material to a large component or repair a feature” → investigate DED.
- “I need very large wire-fed metal deposition” → investigate WAAM.
- “I need coating, repair or deposition with limited conventional melting” → investigate cold spray.
- “I want an extrusion-style workflow and can support debinding/sintering” → investigate bound-metal systems.
Understand the process. Then investigate the machine.
Knowing the process family is the first step. The next ones are part fit, machine evidence and economics — and every tool below is free.
Not sure whether metal AM suits your part? → →Know the process but not the machine? → →Already comparing specific machines? → →Testing whether ownership makes economic sense? → →Already leaning toward a machine? → →