ISO/ASTM TR 52913-1:2025
(Main)Additive manufacturing — Feedstock materials — Part 1: Guidelines for the selection of measurement methods for characterization of powder flow properties
Additive manufacturing — Feedstock materials — Part 1: Guidelines for the selection of measurement methods for characterization of powder flow properties
The document offers guidance on the selection of an appropriate method(s) to measure the flow properties of powders for powder feedstock based additive manufacturing processes. This document offers several definitions and parameters that affect powder flowability, in addition to several references for additional definitions and parameters. It is intended that the guidance provided in this document not only applies to the virgin condition of the powder but also the used powder as a result of any number of successive builds. It is well known that the physical behaviour of the powder is also affected by the manufacturing process itself during the recovery and sieving cycles of the powder during the production processes. This condition of the powder going back into the system can be called out and monitored from successive builds to detect any drift of the powder properties. This document applies to: — the conditions that have an influence on flow properties, and — the necessary information in a test report. This document is aimed for test equipment manufacturers, material suppliers, additive machine manufacturers, and additive manufacturing machine users.
Fabrication additive — Matières premières — Partie 1: Lignes directrices pour la caractérisation des propriétés d'écoulement de la poudre
General Information
Standards Content (Sample)
Technical
Report
ISO/ASTM TR
52913-1
First edition
Additive manufacturing —
2025-10
Feedstock materials —
Part 1:
Guidelines for the selection
of measurement methods for
characterization of powder flow
properties
Fabrication additive — Matières premières —
Partie 1: Lignes directrices pour la caractérisation des propriétés
d'écoulement de la poudre
Reference number
© ISO/ASTM International 2025
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© ISO/ASTM International 2025 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
4.1 General .2
4.2 Measurement procedure conditions .4
5 Apparatus and materials . 5
6 Procedure . 5
7 Test report . 5
Bibliography . 6
© ISO/ASTM International 2025 – All rights reserved
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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This document was prepared by Technical Committee ISO/TC 261, Additive manufacturing, in cooperation
with ASTM Committee F42, Additive Manufacturing Technologies, on the basis of a partnership agreement
between ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on
Additive Manufacturing, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 438, Additive manufacturing, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
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© ISO/ASTM International 2025 – All rights reserved
iv
Introduction
The increased application of additive manufacturing creates a demand by stakeholders for a guidance
document which describes process characteristics and performance regarding general test methods for
the characterization of powder flow properties. In powder feedstock based processes, the flow properties
of the powder are of decisive importance related to the process reliability of an additive manufacturing
process and the quality of the manufactured parts. Characterization of powder flow properties is subject
to numerous variables. The meaningfulness of the results of the measurement therefore depends on these
variables. However, complete consideration of all variables might be neither cost-effective or time effective.
Therefore, when measuring the flow properties, the nature and scope of the measurements to be conducted
is an important issue.
The information contained in the document is applicable to the conditions that have an influence on flow
properties, and the necessary information in a test report.
This information is provided is of interest to test equipment manufacturers, material suppliers, additive
machine manufacturers, and additive manufacturing machine users.
© ISO/ASTM International 2025 – All rights reserved
v
Technical Report ISO/ASTM TR 52913-1:2025(en)
Additive manufacturing — Feedstock materials —
Part 1:
Guidelines for the selection of measurement methods for
characterization of powder flow properties
1 Scope
The document offers guidance on the selection of an appropriate method(s) to measure the flow properties
of powders for powder feedstock based additive manufacturing processes. This document offers several
definitions and parameters that affect powder flowability, in addition to several references for additional
definitions and parameters.
It is intended that the guidance provided in this document not only applies to the virgin condition of the
powder but also the used powder as a result of any number of successive builds. It is well known that the
physical behaviour of the powder is also affected by the manufacturing process itself during the recovery
and sieving cycles of the powder during the production processes. This condition of the powder going back
into the system can be called out and monitored from successive builds to detect any drift of the powder
properties.
This document applies to:
— the conditions that have an influence on flow properties, and
— the necessary information in a test report.
This document is aimed for test equipment manufacturers, material suppliers, additive machine
manufacturers, and additive manufacturing machine users.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/ASTM 52900 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
powder flowability
ability of a solid bulk material to flow
Note 1 to entry: Powder flowability is a function of multiple factors, and particularly powder size and distribution, see
also ISO/ASTM 52907.
© ISO/ASTM International 2025 – All rights reserved
[SOURCE: ISO/ASTM TR 52952:2023, 3.2, modified — Note 1 to entry added.]
3.2
angle of repose
angle formed with the horizontal by the surface of a conical heap of material falling slowly and regularly
from a small height onto a horizontal stationary surface, it is expressed in degrees
[SOURCE: ISO 5048:1989, 2.2, modified — repetition of defined term deleted.]
3.3
rheology
science of deformation, behaviour and flow behaviour of materials
[SOURCE: ISO 3219-1:2021, 3.28]
3.4
cohesion
state in which the particles of a single substance are held together by intermolecular forces
[SOURCE: ISO 472:2013, 2.158]
3.5
consolidation
process in which a powder or compact is densified
[SOURCE: ISO 3252:2023, 3.2.16]
3.6
aeration
introduction of air or oxygen
[SOURCE: ISO 6707-1:2020, 3.5.1.52]
3.7
avalanche
mass of powder moving in a swift motion down over a precipice, as in a rotating drum
3.8
shear rate
property that indicates the forces required to shear one consolidated powder plane relative to another
3.9
flow rate
property that indicates the friction among constituent particles
4 Principle
4.1 General
Powders are bulk assemblies containing particles, liquid (i.e., moisture on the surface of the particle or
within its structure), and gases, normally in the form of atmospheric gas (i.e. air). The interaction of these
three phases governs bulk powder behaviour, often referred to as powder flow.
Powder flow is influenced by multiple factors covered by the following categories:
— Physical properties of the particles, including size distribution, morphology (including satellites), and
surface properties.
— Cohesive strength due to Van der Waals, electrostatic and/or electromagnetic forces, as well as capillary
bonds as a consequence of moisture adsorbed on the surface of particles.
© ISO/ASTM International 2025 – All rights reserved
— Gas content of the powder bed throughout the execution of the process, which affects all interactions
between particles and therefore the overall behaviour of the bulk.
— Environmental conditions such as temperature, humidity, aeration, consolidation and flow rate/shear rate.
The above listed characteristics have influences on a suitable measuring method and the measuring
boundary conditions. The powder flow is generally assessed in this context.
The flow properties of the powder are of importance for the process reliability of an additive manufacturing
process and the quality of the manufactured parts. Suitable properties are essential at various points
(storage, transportation, delivery of powder to the build chamber) of the powder feedstock based additive
manufacturing process.
In the practical use of a powder feedstock based additive manufacturing process, the flow behaviour
depends on the following parameters:
a) material composition,
b) particles (size distribution, shape),
c) shear rate,
d) stress conditions,
e) ambient conditions in process (temperature, pressure, and humidity),
f) storage conditions (temperature and humidity),
g) boundary conditions.
Different methods have been developed to evaluate the flow properties of powders. The list below only
presents examples of methods and terms that can be used and is not intended to be exhaustive. Additional
methods can be found in ISO/ASTM 52907.
1) Methods:
— funnel flowmeter;
— flow through an orifice;
— shear cell;
— avalanche;
— rotating drum.
2) Terms:
— rheology;
— spreadability;
— density (e.g. packing, tap);
— wall friction;
— angle of repose;
— shear(flow) r
...
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