Summary
ISO/ASTM 52900 is the shared vocabulary baseline for additive manufacturing, giving engineers, buyers, researchers, educators, and standards users a common technical language. [1] The 2021 edition is formally designated ISO/ASTM 52900:2021, Edition 2, and its official title is Additive manufacturing — General principles — Fundamentals and vocabulary. [1] As of June 2, 2026, the live ISO catalogue lists this edition as Published and notes that it was reviewed and confirmed in 2025, so the 2021 document remains current on that date. [1] This article explains what the standard covers, why consistent definitions matter, how it separates additive manufacturing from looser “3D printing” usage, and how to apply its terminology without mixing process categories, materials, machine labels, and outcomes. [1] [5]
What ISO/ASTM 52900 Is — and Why It Exists
ISO/ASTM 52900:2021 is a joint ISO and ASTM terminology standard titled Additive manufacturing — General principles — Fundamentals and vocabulary. [1] ISO identifies it as Edition 2, published in November 2021 under ISO/TC 261. [1] Its role is narrow but foundational: it defines the terms used in additive manufacturing technology and groups them by field of application. [5] In practice, ISO/ASTM 52900 gives standards writers, engineers, procurement teams, educators, and researchers a shared vocabulary and classification baseline. [5] It is not a machine-qualification standard, a material specification, or a part-approval document. [5] [9]
A terminology standard exists because later AM standards depend on stable language. Without agreed definitions, the same label can refer to a process family, a machine architecture, a feedstock, or a finished result. The document also names no normative reference standards, reinforcing its role as a base vocabulary rather than a dependent technical requirement. [5]
Status, History, and Where 52900 Sits in the Standards Timeline
The terminology line behind ISO/ASTM 52900 grew out of earlier ASTM work, especially ASTM F2792, which ASTM describes as the first AM terminology standard and a historical precursor to the joint ISO/ASTM vocabulary line. [7] ASTM’s current additive manufacturing standards page lists F2792-12a as withdrawn in 2015 and lists ISO/ASTM 52900-21 in the terminology section. [3] ISO’s life-cycle record shows that ISO/ASTM 52900:2015 was Edition 1, later withdrawn, and revised by ISO/ASTM 52900:2021. [1] The 2021 document therefore sits in a clear lineage rather than a separate vocabulary effort. [1]
The 2021 edition matters because ISO identifies it as Edition 2 and because it expands the older terminology-only framing into a fundamentals-and-vocabulary document. [1] [7] Its place in the standards stack is still the same: align the language used across technical documents, contracts, research papers, and related AM standards. [3] [7]
Legacy baseline versus live catalogue status
Historical importance and live status are separate questions. As of June 2, 2026, ISO lists ISO/ASTM 52900:2021 as Published, shows the 2015 edition as withdrawn, and states that the 2021 edition was reviewed and confirmed in 2025. Readers citing it later should still verify the live catalogue. [1]
How ISO/ASTM 52900 Defines Additive Manufacturing
In the ISO 52900 standard, additive manufacturing is defined by process logic: making parts from 3D model data by joining materials, typically layer by layer, rather than mainly cutting material away or shaping it with molds, dies, or other formative tooling. [6] The key elements are the digital model, the joining of material, and the fact that the output is a manufactured part. “Usually layer by layer” captures the dominant build strategy without reducing every AM process to a simple stack of identical slices. [6]
The definition is intentionally broad because it describes a manufacturing principle, not a consumer label or a single machine type. Subtractive manufacturing reaches geometry by removing material from stock. Formative manufacturing reaches geometry through tooling and deformation. Additive manufacturing instead builds geometry through controlled material addition and consolidation. That boundary helps readers interpret later terms without assuming that every machine marketed as a printer, every resin system, or every metal build process belongs to the same subgroup. [6] [9]
Additive Manufacturing vs 3D Printing: The Terminology Boundary
ISO/ASTM 52900 treats additive manufacturing as the broader technical concept and treats 3D printing more narrowly as fabricating objects by depositing material through a print head, nozzle, or similar printer mechanism. [6] The standard also notes that “3D printing” is often used non-technically as a synonym for AM, which is why careful vocabulary matters in professional documents. [6]
- AM vs 3D printing: In casual speech, the terms often overlap. In standards language, AM is the broader manufacturing principle, while 3D printing has a narrower deposition-oriented meaning. [6]
- VPP vs “all resin printers are SLA”: Vat photopolymerization is the ISO top-level category. Later ASTM VPP work explicitly covers both laser-scanning and mask-projection variants, so one familiar label should not be used as the umbrella for every resin system. [5] [11]
- MEX vs FDM/FFF: Material extrusion is the ISO category. FDM and FFF are common market or shop-floor labels for material-extrusion systems, not top-level ISO category names. [5] [10]
- PBF vs SLM/DMLS/SLS confusion: Powder bed fusion is the ISO category. Terms such as SLM, DMLS, EBM, and SLS are narrower process labels commonly used inside metal or polymer PBF contexts. [5] [10]
- DED vs WAAM/laser cladding conflation: Directed energy deposition is the ISO category. WAAM is a DED technology, while terms such as laser cladding should not be mistaken for separate top-level ISO AM categories in this terminology framework. [5] [12]
The Seven Process Categories in ISO/ASTM 52900
ISO/ASTM 52900 organizes additive manufacturing into seven top-level process categories. [5] This is a taxonomy, not a ranking of quality, accuracy, cost, or industrial maturity. The categories group processes by the basic way material is deposited, joined, fused, cured, or laminated. [5] [8]
Common market labels map imperfectly onto this structure. In vendor literature or shop-floor speech, a label may describe a machine architecture, a trademarked process name, an energy source, a feedstock format, or a familiar shorthand. ASTM and other industry references still frame the ISO/ASTM 52900 categories as the higher-level classification layer. [8] [10] [11] [12]
| Process category | Abbreviation | Core definition cue | Common market terms/examples |
|---|---|---|---|
| Binder jetting | BJT | A liquid bonding agent is selectively deposited to join powder materials. [5] | No reliable figure found. |
| Directed energy deposition | DED | Focused thermal energy fuses material as it is being deposited. [5] | WAAM is a DED technology; terms such as laser cladding are not separate ISO top-level categories here. [12] |
| Material extrusion | MEX | Material is selectively dispensed through a nozzle or orifice. [5] | FDM and FFF are common market or process labels. [10] |
| Material jetting | MJT | Droplets of feedstock material are selectively deposited. [5] | Photopolymer resin and wax are example feedstocks. [5] |
| Powder bed fusion | PBF | Thermal energy selectively fuses regions of a powder bed. [5] | SLS, SLM, DMLS, and EBM are common narrower labels in PBF contexts. [10] |
| Sheet lamination | SHL | Sheets of material are bonded to form a part. [5] | No reliable figure found. |
| Vat photopolymerization | VPP | Liquid photopolymer in a vat is selectively cured by light-activated polymerization. [5] | Verified VPP variants include laser-scanning and mask-projection approaches; no single market label cleanly covers the whole category. [11] |
How the Standard Organizes Its Vocabulary
ISO/ASTM 52900 is structured as a reference document, not as a process tutorial. Its accessible scope says the terms are defined for additive manufacturing technology and classified by field of application. [5] The visible contents show sections for general terms, process categories, processing, materials, parts, properties, and evaluation, helping readers locate a term in the right conceptual area before using it in drawings, procedures, specifications, or research. [5]
The annex structure matters as well. Annex A is normative, while Annex B is informative. [5] The annexes therefore do not carry the same interpretive weight: normative material is part of the standard’s formal content, while informative material supports understanding. The document also omits normative references, underscoring its role as a foundational vocabulary source rather than a document that depends on other standards for its basic terminology. [5]
The alphabetical index begins on page 26. [5] In practice, that makes the standard easier to navigate when a reader knows a term but not the section in which it is defined. [5]
Why ISO/ASTM 52900 Matters in Practice
ISO/ASTM 52900 matters because AM work routinely crosses organizational boundaries. A designer may write a drawing note, a buyer may issue an RFQ, a supplier may interpret the process language, and a quality team may review the part record. Shared terminology reduces avoidable ambiguity in procurement, documentation, training, and cross-vendor communication. [3] [8] [9] ISO and ASTM both present additive manufacturing as a broader standards environment, which makes a stable vocabulary especially useful. [2] [3]
The vocabulary baseline also helps normalize market-facing language. TCT’s 2026 machine guide, for example, says its systems are organized using ASTM ISO 52900 classifications and then layers manufacturer-specific profiles and detailed specifications on top. [10] That is the kind of mixed-language environment in which category names, process labels, and vendor positioning can blur together unless a common standards vocabulary comes first. [10] ISO/ASTM 52900 helps people communicate consistently, but it does not by itself establish product quality, qualification, or compliance. [1] [9]
- RFQs and procurement language: Name the recognized process category first so buyers and suppliers are not relying only on brand or shop shorthand.
- QA and audit language: Use consistent terms in inspection records, travelers, and nonconformance reports.
- Technical writing: Keep drawings, datasheets, manuals, and reports from mixing category names with trade labels.
- Training and onboarding: Give new staff a stable vocabulary before they learn machine-specific procedures.
- Standards cross-references: Shared terminology makes related AM documents easier to compare and interpret.
What ISO/ASTM 52900 Does Not Do
ISO/ASTM 52900 is a terminology standard. Its scope is to define AM terms and organize them into a shared vocabulary framework. [5] That means it does not provide acceptance criteria, machine qualification, a material-property database, safety certification, production approval, or guaranteed interoperability between machines, software, materials, or suppliers. [5] [9] Those subjects belong to other standards, practices, test methods, and qualification schemes in the broader additive-manufacturing ecosystem. [3] [9] In short, ISO/ASTM 52900 helps people use the same words; it does not prove that a part, process, machine, or organization is fit for a particular contractual or regulated purpose. [5] [9]
Standards Ecosystem Context Around 52900
ISO/ASTM 52900 sits in a wider standards environment shared by ISO, ASTM, and national metrology bodies. ISO attributes the 2021 document to ISO/TC 261. [1] ASTM’s F42.91 terminology jurisdiction page lists ISO/ASTM 52900-21 as the active matching terminology standard and shows F2792 as withdrawn. [4] ISO’s additive manufacturing sector page presents 52900 alongside other AM standards on processes, safety, qualification, feedstocks, and performance. [2]
Terminology standards sit upstream because later documents need stable words before they can specify tests, requirements, reporting formats, or qualification logic. If one document uses a process name differently from another, technical comparisons become unreliable before performance is even discussed. That is why 52900 functions as connective tissue in the standards stack: it establishes the vocabulary first, then leaves measurement, materials, qualification, safety, and application-specific requirements to other documents. [2] [3] [9]
Practical Guidance for Using ISO/ASTM 52900 in Real Documents
Use ISO/ASTM 52900 as a drafting reference for specifications, RFQs, work instructions, inspection forms, and training material. Start with the formal category name from the seven-category structure, then add narrower process names only when they convey necessary extra detail. [5] This keeps classification consistent even when a document also mentions a machine type, feedstock, energy source, or supplier-specific label. [5]
A practical pattern is to name the ISO category first and the familiar label second, such as “material extrusion (FFF in this document)” or “powder bed fusion using a laser-based system.” Because “3D printing” is often used loosely outside standards work, documents should state whether they mean the broad AM field or the narrower printer-style deposition sense. [6] That approach improves clarity without turning a standards document into brand-specific language. [6] [10]
FAQ
What is ISO/ASTM 52900?
ISO/ASTM 52900:2021 is the joint ISO/ASTM fundamentals and vocabulary standard for additive manufacturing. [1] It provides the core terminology and classification framework used across many 3D printing standards and AM documents. [1] [3]
Is ISO 52900 the same as ISO/ASTM 52900?
In practice, people often shorten the name to “ISO 52900,” but the formal designation is ISO/ASTM 52900:2021. [1] In controlled documents, the joint designation is the better choice because it reflects the coordinated ISO/ASTM standards line. [1]
Is ISO/ASTM 52900:2021 current?
As of June 2, 2026, yes. ISO lists the document as Published and says it was reviewed and confirmed in 2025, so the 2021 edition remains current on the ISO catalogue at that date. [1] If you cite it later, check the live ISO record again. [1]
How does ISO 52900 define additive manufacturing?
The standard defines additive manufacturing in broad process terms: making parts from 3D model data by joining materials, typically layer by layer, rather than by primarily subtractive or formative methods. [6] That wording is designed to cover multiple AM process families, not just consumer-style printers. [6]
What does ISO/ASTM 52900 cover?
It covers fundamentals and vocabulary. More specifically, it defines AM terms, groups them by field of application, and includes the seven top-level process categories used in the standard’s taxonomy. [1] [5] It should be read as a terminology and classification reference, not as a process manual. [5]
How should experts map market labels like FDM, SLA, DMLS, or WAAM?
Map the ISO category first, then add the familiar label if useful. FDM/FFF belong under material extrusion, common metal and polymer labels such as DMLS, SLM, EBM, and SLS sit within powder bed fusion contexts, and WAAM is a DED technology. [10] [11] [12] The standards-level category should remain the primary label. [5]
Does ISO/ASTM 52900 provide qualification or acceptance criteria?
No. ISO/ASTM 52900 provides definitions and classification language, but it does not qualify machines, approve parts, certify materials, define acceptance limits, or guarantee supplier interoperability. [5] [9] Those tasks belong to other standards and qualification frameworks. [3] [9]
Conclusion — Why ISO/ASTM 52900 Still Matters
ISO/ASTM 52900 still matters because additive manufacturing depends on shared language before it can depend on shared specifications. The standard gives the field a common vocabulary for naming processes, interpreting definitions, and aligning technical documents across the broader AM standards family. [1] [3] As of June 2, 2026, ISO lists ISO/ASTM 52900:2021 as the published, confirmed edition, which means the 2021 text remains the live baseline on that date. [1] In plain terms, it helps people mean the same thing when they use the same words. [1] [3]
Sources
- ISO standard page for ISO/ASTM 52900:2021
- ISO additive manufacturing sector page
- ASTM additive manufacturing standards page
- ASTM F42.91 terminology jurisdiction page
- EN ISO/ASTM 52900:2021 preview page
- FPREN ISO/ASTM 52900 preview page
- ASTM article on important AM standards
- ASTM article on AM process categories
- NIST additive manufacturing FAQs
- TCT AM Machine Guide 2026
- ASTM work item on vat photopolymerization
- ASTM work item on wire arc additive manufacturing
