LPBF, DMLS, SLM, DMLM and SLS are often treated as competing process names. In reality, some are standardized process categories, while others are historical or supplier-associated terms. The terminology matters because confusing metal and polymer powder-bed processes can lead to incorrect material, design and qualification assumptions.
For process-neutral technical communication, use the standardized category first and add the commercial term only when it helps identify a specific machine or legacy data set.
The clearest terminology
| Term | What it usually means | Recommended use |
|---|---|---|
| PBF-LB/M | Powder bed fusion of metal using a laser beam | Most precise standardized-style notation for metal laser powder bed fusion |
| LPBF or L-PBF | Laser powder bed fusion | Widely accepted general term for metal laser powder-bed processes |
| DMLS | Direct Metal Laser Sintering | Legacy and supplier-associated term, strongly linked with EOS; commonly refers to metal LPBF |
| SLM | Selective Laser Melting | Historical industry term for metal LPBF; also associated with the former SLM Solutions brand |
| DMLM | Direct Metal Laser Melting | Supplier-used term for metal LPBF, notably used in parts of the GE Additive ecosystem |
| PBF-LB/P | Powder bed fusion of polymer using a laser beam | Precise category for laser-based polymer powder bed fusion |
| SLS | Selective Laser Sintering | Most commonly used for polymer powder bed fusion; avoid using it as a generic label for modern metal LPBF |
| PBF-EB/M | Powder bed fusion of metal using an electron beam | Process-neutral term for electron-beam metal powder bed fusion |
LPBF: the broad industrial term
Laser powder bed fusion describes a process in which a laser selectively melts regions of a thin metal-powder layer. After each layer, the build platform moves and the recoater spreads fresh powder. The cycle continues until the part is complete. The finished component normally requires depowdering, stress relief or heat treatment, removal from the build plate, support removal and often machining or surface finishing.
LPBF is the preferred broad term because it describes the physical process without implying a particular machine supplier. The notation PBF-LB/M goes one step further by identifying the process category, energy source and material class.
DMLS, SLM and DMLM: different labels, not fundamentally different physics
Older explanations often claim that DMLS only sinters metal powder while SLM or DMLM fully melts it. That distinction is misleading for modern commercial metal systems. Production metal powder-bed machines marketed under these names generally create a melt pool and consolidate metal through melting and solidification.
The practical differences between two metal LPBF systems usually come from machine architecture, laser configuration, gas flow, recoating system, parameter set, powder specification, software, monitoring, build strategy and validated post-processing — not from the word used in the acronym.
DMLS
DMLS is a widely recognized commercial and historical term associated with EOS. Engineers may still encounter it in machine names, material data, qualification documents and customer specifications. When discussing the general process, however, LPBF or PBF-LB/M is clearer.
SLM
SLM became a common industry term for fully melted metal-powder processes and was also embedded in the name SLM Solutions, now Nikon SLM Solutions. It remains understandable, but it is less neutral than LPBF.
DMLM
DMLM is another supplier-associated expression for metal laser melting. It should be interpreted as a metal LPBF route unless the governing process specification defines something more specific.
Why SLS should usually be reserved for polymers
Selective laser sintering is most commonly used for polymer powder bed fusion, especially polyamide systems. The powder surrounding the part provides support, so polymer SLS parts usually do not need the attached support structures typical of metal LPBF. Thermal control, powder refresh, nesting strategy and post-processing are also fundamentally different from the metal route.
Using SLS as a catch-all term for metal and polymer processes creates confusion. A better distinction is:
- Metal: LPBF or PBF-LB/M.
- Polymer: SLS or, in standards-oriented writing, PBF-LB/P.
- Electron-beam metal: PBF-EB/M.
What actually changes part performance
The acronym does not determine the final properties. The following variables matter far more:
- Alloy and powder specification, including chemistry, particle-size distribution, morphology and reuse history
- Machine model, laser configuration, scan strategy, gas flow, recoater and calibration status
- Build orientation, support and anchoring strategy, part location and thermal history
- Layer thickness, energy input and the validated process parameter set
- Stress relief, solution treatment, aging, hot isostatic pressing and other thermal operations
- Support removal, machining, surface finishing and cleaning
- Inspection plan, test coupon strategy and acceptance criteria
A practical naming rule for engineers
- Use LPBF in general engineering communication about laser-based metal powder bed fusion.
- Use PBF-LB/M when writing standards-oriented specifications, process maps or qualification documents.
- Retain DMLS, SLM or DMLM when quoting a machine supplier, legacy document, trademark, customer specification or established program terminology.
- Use SLS mainly for polymer powder bed fusion.
- Do not infer material properties from the acronym. Reference the qualified machine–material–parameter–post-process route.
LPBF vs SLS: quick comparison
| Characteristic | Metal LPBF / PBF-LB/M | Polymer SLS / PBF-LB/P |
|---|---|---|
| Typical feedstock | Metal alloy powder | Thermoplastic powder, commonly polyamides |
| Consolidation | Localized melting and solidification | Thermal fusion of polymer particles |
| Attached supports | Commonly required for anchoring and heat transfer | Usually not required because surrounding powder supports the part |
| Atmosphere | Controlled inert environment; reactive alloys require strict oxygen control | Heated process chamber with controlled thermal history |
| Post-processing | Depowdering, heat treatment, cut-off, support removal, machining/finishing as needed | Cooling, depowdering, cleaning, dyeing or finishing as needed |
| Main design concern | Thermal stress, distortion, supports, recoater interaction, trapped powder | Thermal shrinkage, nesting, powder aging, escape paths and surface texture |
Frequently asked questions
Is DMLS a sintering process?
Despite the name, modern commercial DMLS systems used for structural metal parts generally form a melt pool. Treating DMLS as a fundamentally lower-density partial-sintering route is not a reliable technical distinction.
Are SLM and LPBF the same?
In most present-day industrial discussions, SLM refers to a metal LPBF process. LPBF is the broader and more supplier-neutral term.
Can SLS print metal?
The term has historically been used broadly, but modern engineering communication normally reserves SLS for polymer powder bed fusion. For metal, use LPBF or PBF-LB/M.
Does the terminology affect qualification?
Qualification is tied to the defined production route, not to a marketing acronym. The governing specification should identify equipment, feedstock, parameters, post-processing, inspection and change-control requirements.
Conclusion
LPBF is the most useful general label for laser-based metal powder bed fusion. DMLS, SLM and DMLM are best understood as legacy or supplier-associated names within that process family. SLS is normally a polymer process. Clear terminology reduces ambiguity, but the final part is defined by the complete, qualified manufacturing route.
Related Addithive resources: Design for LPBF · Metal AM Process Selection