EN ISO/ASTM 52908:2023
(Main)Additive manufacturing of metals - Finished Part properties - Post-processing, inspection and testing of parts produced by powder bed fusion (ISO/ASTM 52908:2023)
Additive manufacturing of metals - Finished Part properties - Post-processing, inspection and testing of parts produced by powder bed fusion (ISO/ASTM 52908:2023)
This document specifies requirements for the qualification, quality assurance and post processing for metal parts made by powder bed fusion.
This document specifies methods and procedures for testing and qualification of various characteristics of metallic parts made by additive manufacturing powder bed fusion processes, in accordance with ISO/ASTM 52927, categories H and M.
This document is intended to be used by part providers and/or customers of parts.
This document specifies qualification procedures where appropriate to meet defined quality levels.
Additive Fertigung von Metallen - Eigenschaften von Fertigteilen - Nachbearbeitung, Inspektion und Prüfung von Bauteilen hergestellt mittels pulverbettbasiertem Schmelzen (ISO/ASTM 52908:2023)
Dieses Dokument legt Anforderungen für die Qualifikation, Qualitätssicherung und Nachbearbeitung von Metallteilen fest, die durch pulverbettbasiertes Schmelzen hergestellt werden.
Dieses Dokument legt Verfahren und Vorgehensweisen zur Prüfung und Qualifizierung verschiedener Eigenschaften von durch pulverbettbasiertes Schmelzen in der additiven Fertigung hergestellten Metallteilen, in Übereinstimmung mit ISO/ASTM 52927, Kategorie H und Kategorie M fest.
Dieses Dokument ist für Bauteileanbieter und/oder Kunden von Bauteilen bestimmt.
Dieses Dokument legt Qualifikationsverfahren fest, um die definierten Qualitätsstandards zu erfüllen.
Fabrication additive de métaux - Propriétés des pièces finies - Post-traitement, inspection et essais des pièces produites par fusion sur lit de poudre (ISO/ASTM 52908:2023)
Le présent document spécifie les exigences pour la qualification, l’assurance qualité et le post-traitement pour les pièces métalliques fabriquées par fusion sur lit de poudre.
Le présent document spécifie des méthodes et des modes opératoires pour les essais et la qualification de différentes caractéristiques de pièces métalliques fabriquées de manière additive par fusion sur lit de poudre, conformément à l’ISO/ASTM 52927, catégories H et M.
Le présent document est destiné à être utilisé par des fournisseurs de pièces et/ou par des clients de pièces.
Le présent document spécifie des procédures de qualification permettant le cas échéant d’atteindre les niveaux de qualité définis.
Dodajalna izdelava kovinskih izdelkov - Lastnosti končnih delov - Končna obdelava, kontrola in preskušanje delov, izdelanih s spajanjem prahu na podlagi (ISO/ASTM 52908:2023)
Ta dokument določa zahteve za usposobljenost, zagotavljanje kakovosti in naknadno obdelavo
kovinskih delov, izdelanih s spajanjem prahu v postelji.
Ta dokument določa metode in postopke za preskušanje in kvalifikacijo različnih lastnosti kovinskih delov, izdelanih v postopkih aditivne proizvodnje s spajanjem prahu v postelji, v skladu s standardom ISO/ASTM 52927, kategoriji H in M.
Ta dokument je namenjen za uporabo ponudnikov delov in/ali kupcev delov.
Ta dokument določa postopke kvalificiranja za izpolnjevanje opredeljenih stopenj kakovosti, kjer je ustrezno.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2024
Aditivna proizvodnja kovinskih izdelkov - Lastnosti končnih delov - Končna
obdelava, kontrola in preskušanje delov, izdelanih s spajanjem prahu v postelji
(ISO/ASTM 52908:2023)
Additive manufacturing of metals - Finished Part properties - Post-processing, inspection
and testing of parts produced by powder bed fusion (ISO/ASTM 52908:2023)
Additive Fertigung von Metallen - Eigenschaften von Fertigteilen - Nachbearbeitung,
Inspektion und Prüfung von Bauteilen hergestellt mittels pulverbettbasiertem Schmelzen
(ISO/ASTM 52908:2023)
Fabrication additive de métaux - Propriétés des pièces finies - Post-traitement,
inspection et essais des pièces produites par fusion sur lit de poudre (ISO/ASTM
52908:2023)
Ta slovenski standard je istoveten z: EN ISO/ASTM 52908:2023
ICS:
25.030 3D-tiskanje Additive manufacturing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO/ASTM 52908
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2023
EUROPÄISCHE NORM
ICS 25.030
English Version
Additive manufacturing of metals - Finished Part
properties - Post-processing, inspection and testing of
parts produced by powder bed fusion (ISO/ASTM
52908:2023)
Fabrication additive de métaux - Propriétés des pièces Additive Fertigung von Metallen - Eigenschaften von
finies - Post-traitement, inspection et essais des pièces Fertigteilen - Nachbearbeitung, Inspektion und
produites par fusion sur lit de poudre (ISO/ASTM Prüfung von Bauteilen hergestellt mittels
52908:2023) pulverbettbasiertem Schmelzen (ISO/ASTM
52908:2023)
This European Standard was approved by CEN on 19 November 2023.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO/ASTM 52908:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO/ASTM 52908:2023) has been prepared by Technical Committee ISO/TC 261
"Additive manufacturing" in collaboration with Technical Committee CEN/TC 438 “Additive
Manufacturing” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2024, and conflicting national standards shall be
withdrawn at the latest by May 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/ASTM 52908:2023 has been approved by CEN as EN ISO/ASTM 52908:2023 without
any modification.
INTERNATIONAL ISO/ASTM
STANDARD 52908
First edition
2023-11
Additive manufacturing of metals —
Finished part properties — Post-
processing, inspection and testing of
parts produced by powder bed fusion
Fabrication additive de métaux — Propriétés des pièces finies — Post-
traitement, inspection et essais des pièces produites par fusion sur lit
de poudre
Reference number
ISO/ASTM 52908:2023(E)
© ISO/ASTM International 2023
ISO/ASTM 52908:2023(E)
© ISO/ASTM International 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester. In the United States, such requests should be sent to ASTM International.
ISO copyright office ASTM International
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CH-1214 Vernier, Geneva West Conshohocken, PA 19428-2959, USA
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Website: www.iso.org Website: www.astm.org
Published in Switzerland
ii
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviations . 2
5 Qualification . 2
5.1 General . 2
5.2 Part validation . 3
5.3 Technical documentation relating to part(s) produced . 3
5.4 Facility documentation . 3
5.4.1 Additive manufacturer documentation requirements . 3
5.4.2 Subcontractor documentation requirements . 3
5.5 Quality assurance documentation . 4
6 Post processing . 4
6.1 General . 4
6.2 Post-build activities . 4
6.3 Thermal treatment . 5
6.3.1 General . 5
6.3.2 Reducing residual stresses . 5
6.3.3 Reducing anisotropy . 5
6.3.4 Prepare material for mechanical post-processing . 5
6.3.5 Densification . 5
6.3.6 Annealing and aging . 5
6.4 Separation from the built platform and support structures . 6
6.5 Surface finishing . 6
6.5.1 Surface finishing operations . 6
6.5.2 Machining allowances . 6
7 Inspection and testing .6
7.1 General . 6
7.2 Metallurgical testing . 7
7.2.1 Objective . 7
7.2.2 Test specimen selection, design, and preparation for part characterization. 7
7.2.3 Test methods, parameters, and test specimens. 8
7.2.4 Chemical analysis . 9
7.2.5 Metallurgical properties . 9
7.2.6 Determining the non-metallic inclusion content . 9
7.2.7 Analysis and test report . 9
7.3 Material testing . 9
7.3.1 General . 9
7.3.2 Orientation in the build space . 10
7.3.3 Test specimen geometry and surface quality . 10
7.3.4 Density (part) . . 10
7.3.5 Archimedean method.12
7.3.6 Image analysis of metallographic specimens .13
7.4 Mechanical testing . 15
7.4.1 Static testing .15
7.4.2 Dynamic testing . 20
7.5 Surface quality inspection . 21
7.6 Geometrical inspection (form, dimension, and tolerances) . 21
7.7 Non-destructive testing . 21
iii
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Bibliography .23
iv
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
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 ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
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 Objective to create a common set
of ISO/ASTM standards on Additive Manufacturing, and 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).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Introduction
As with conventional manufacturing processes (e.g. casting and milling), metallic parts produced by
additive manufacturing technologies have critical-to-quality characteristics. These characteristics
include density, strength, hardness, surface quality, dimensional accuracy, residual stresses, absence
of cracks, voids, and structural homogeneity, which are typically tested in additively manufactured
components. The quality of additively manufactured components is essential for functional components
produced on an industrial scale. Thus, it is necessary to qualify additive manufacturing processes
according to uniform criteria and to apply standardised in-process and post-process testing.
vi
© ISO/ASTM International 2023 – All rights reserved
INTERNATIONAL STANDARD ISO/ASTM 52908:2023(E)
Additive manufacturing of metals — Finished part
properties — Post-processing, inspection and testing of
parts produced by powder bed fusion
1 Scope
This document specifies requirements for the qualification, quality assurance and post processing for
metal parts made by powder bed fusion.
This document specifies methods and procedures for testing and qualification of various characteristics
of metallic parts made by additive manufacturing powder bed fusion processes, in accordance with
ISO/ASTM 52927, categories H and M.
This document is intended to be used by part providers and/or customers of parts.
This document specifies qualification procedures where appropriate to meet defined quality levels.
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 3369:2006, Impermeable sintered metal materials and hardmetals — Determination of density
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 18265, Metallic materials — Conversion of hardness values
ISO 21920-1, Geometrical product specifications (GPS) — Surface texture: Profile — Part 1: Indication of
surface texture
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
ISO/ASTM 52907, Additive manufacturing — Feedstock materials — Methods to characterize metal
powders
ISO/ASTM 52920, Additive manufacturing — Qualification principles — Requirements for industrial
additive manufacturing processes and production sites
ISO/ASTM 52927, Additive manufacturing — General principles — Main characteristics and corresponding
1)
test methods
2)
ISO/ASTM 52928, Additive manufacturing — Feedstock materials — Powder life cycle management
ISO/ASTM/TS 52930, Additive manufacturing — Qualification principles — Installation, operation and
performance (IQ/OQ/PQ) of PBF-LB equipment
ANSI/ASME Y14.5, Dimensioning and Tolerancing
ASTM B311, Standard Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than
Two Percent Porosity
1) Under preparation. Stage at the time of publication: ISO/DIS 52927:2023.
2) Under preparation. Stage at the time of publication: ISO/DIS 52928:2023.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
ASTM B962, Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products
Using Archimedes’ Principle
ASTM E8/E8M, Standard Test Methods for Tension Testing of Metallic Materials
DIN 50125, Testing of metallic materials — Tensile test pieces
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
grain size
average grain size in the metallurgical structure when viewed in cross-section
4 Abbreviations
The abbreviations listed in Table 2 are used throughout this document.
Table 2 — Abbreviations
AM additive manufacturing
EDX energy-dispersive X-ray spectroscopy
SEM scanning electron microscope
CAD computer aided design
NDT non-destructive testing
QA quality assurance
COC certificate of conformance
ASL approved supplier list
HIP hot isostatic pressing
EDM electrical discharge machining
PBF powder bed fusion
5 Qualification
5.1 General
The manufacturer shall demonstrate the capability to produce AM parts to the requirements given in
the purchase specification. The inspection and testing described in the following clauses are performed
and assessed using the methods and acceptance criteria stated in the purchase specification.
NOTE Inspection and testing methods are specified at the design stage, as described in ISO/ASTM 52927,
and are in accordance with the relevant standards and regulations that are required for the conformity of that
part.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
5.2 Part validation
Validation that the part produced complies with the requirements of the purchase specification shall be
captured in a qualification record. A typical ‘qualification record’, shall consist of:
— technical documentation relating to part(s) produced;
— facility documentation;
— quality assurance (QA) documentation.
5.3 Technical documentation relating to part(s) produced
The technical documentation relating to part(s) produced shall contain:
— part specification in accordance with ISO/ASTM 52927, which includes inspection methods,
associated plans, acceptance criteria, and representative quality indicators where applicable;
— feedstock specification, test results and declaration of conformity in accordance with
ISO/ASTM 52907;
— material specification (consolidated product material properties specification);
— manufacturing plan (e.g. see ISO/ASTM 52904);
— records of destructive and non-destructive testing;
— inspection record for the part (in accordance with the purchase specification);
— other documentation required by the purchaser, regulation or product standard (e. g. material
identification, labelling, product instructions).
NOTE 1 For some materials, there is a singular specification that controls both feedstock and material
properties, such as metallurgical and mechanical properties.
NOTE 2 Technical specifications for metal powders are addressed in ISO /ASTM 52907.
5.4 Facility documentation
5.4.1 Additive manufacturer documentation requirements
Facility documentation requirements for industrial manufacturing sites are addressed in
ISO/ASTM 52920.
For the purpose of this document, an outline of the relevant manufacturing plant and equipment shall
be provided at the request of the buyer. The outline shall include the major items of equipment used for
post processing, inspection, and testing (including details of geographical location).
The following facility documentation shall be provided:
— records of equipment qualification in accordance with ISO/ASTM TS 52930;
— records of powder lifecycle management in accordance with ISO/ASTM 52928.
The requirements in this subclause are met where a quality management system is in place (see 5.5).
5.4.2 Subcontractor documentation requirements
Where the manufacturer subcontracts post-processing and/or testing activities, the manufacturer
shall be able to indicate the conditions under which these activities are subcontracted and shall provide
a purchase specification for the operations involved.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
The manufacturer shall assess and approve the subcontractors for their capability to perform the
subcontracted activity to the required quality level.
5.5 Quality assurance documentation
General QA documentation requirements are met by introducing a quality management system (e.g.
ISO 9001 or ISO 13485).
Additive manufacturing QA documentation requirements shall be in accordance with ISO/ASTM 52920.
6 Post processing
6.1 General
Post-processing consists of activities performed after the completion of a build cycle but prior to final
inspection activities.
NOTE Intermediate inspection can be performed between post-processing activities.
Post-processing operations are typically performed to achieve the desired material properties, final
geometry and surface finish, and can include the following steps:
— post-build activities (e.g. cool down, declamping, removal from the AM machine, part cleaning);
— thermal treatment;
— separation from the build platform and support structures;
— surface finishing.
At the post-processing stage there are also several system-based operations performed (i.e. not related
to the AM part) to prepare for subsequent builds. These activities are covered within other standards
and include:
— recovery and reprocessing of unfused powder (in accordance with ISO/ASTM 52928);
— AM equipment cleaning and maintenance (in accordance with ISO/ASTM 52920).
6.2 Post-build activities
Following successful completion of the build, the chamber is allowed to cool and unfused powder is
recovered from the build chamber. Once the build chamber is opened, the build platform fasteners
can be removed, and care shall be taken to avoid deflection, which could induce cracking, due to the
build-up of any residual stresses within the build. (see ASTM F3530-22)
Once the build assembly is removed from the AM machine, it can be cleaned and visually inspected
(e.g. for imperfections, discolouration, separation from support structures). Loose powder that remains
on the build assembly after exposure to atmosphere (i.e. no longer within an inert environment) can
be removed by various methods (e.g. compressed gas, brushing, vacuum, sonic or ultrasonic cleaning
methods). Loose powder removed at this stage shall be considered to be waste powder and disposed of
safely.
For some non-reactive materials, loose powder that is removed within a controlled environment (e.g.
glovebox, automatic depowdering unit), can also be reused where allowed by the manufacturer’s
procedures, subject to contamination and traceability controls.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
6.3 Thermal treatment
6.3.1 General
Although it is not mandatory to apply any thermal treatment to additively manufactured parts, the
following points should be considered.
NOTE Thermal treatment is executed after it is ensured that all powder located in internal channels is
removed.
6.3.2 Reducing residual stresses
The build-up of successive layers with rapid heating and cooling generates residual stresses in
the component, which can lead to distortion. Where used, support structures help to minimise this
distortion by providing stiffness within the build assembly to resist deflection due to these residual
stresses. Therefore, the build assembly is typically stress relieved prior to the removal of any support
structures, although this is not mandatory. The release of thermal stresses can lead to distortion, over
a short or prolonged period of time. Furthermore, local stress peaks can occur in the part, which can
significantly reduce fatigue strength and lead to premature cracking. Stress-relief reduces stresses in
the component in a controlled manner after manufacture, thereby preventing distortion.
6.3.3 Reducing anisotropy
The as-built part can exhibit anisotropy, which may be normalised to minimise the orientation
and location dependence on the mechanical properties of the formed material and achieve the final
mechanical property requirements.
NOTE ISO/ASTM 52909 includes supplementary guidelines for the evaluation of finished part properties,
including orientation and location dependence, for metal parts produced by powder bed fusion.
6.3.4 Prepare material for mechanical post-processing
Processes such as annealing can reduce the hardness of the as-built material to facilitate subsequent
machining operations. Annealing, followed by ageing, can reduce intergranular corrosion and cracking.
6.3.5 Densification
Hot isostatic pressing (HIP) can improve material properties through the reduction of porosity and
anisotropy.
NOTE 1 ASTM A 1080/A 1080M provides a standard practice for hot isostatic pressing of steels, stainless
steels and related alloys.
The thermal treatment specified depends on the material and desired mechanical properties, as defined
within the material specification and agreed between manufacturer and purchaser.
NOTE 2 ASTM F 3301a includes details of thermal treatments for various metals produced by powder bed
fusion.
Test specimens used for destructive testing shall be representative of the part and therefore be
subjected to the same thermal post-processing operations as the part they represent.
6.3.6 Annealing and aging
Annealing, followed by ageing, can also enable grain boundary carbides to enter into solution and thus
prevent unacceptable grain boundary carbide precipitation, which can lead to intergranular corrosion
and cracking.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
6.4 Separation from the built platform and support structures
Various items can be present within the build assembly, which require separation from the build
platform, from support structure and/or from other items (e.g. the part, test specimens). A suitable
method of separation shall be specified in the manufacturing plan, such that separation does not have
a detrimental effect on the integrity of the part or test specimens, e.g. wire EDM, metallographic saw,
breaking parts off by hand.
Separation from the build platform should be studied to determine the best method and when to be
performed (see 6.3.2).
6.5 Surface finishing
6.5.1 Surface finishing operations
Suitable finishing operations may be selected by the manufacturer and shall be defined within the
manufacturing plan, to achieve the final geometry and surface finish requirements, specified in the
design.
NOTE Numerous finishing operations are available, examples of which are listed below:
— machining (e.g. turning, drilling, milling);
— electrical discharge machining (EDM);
— abrasive operations (e.g. grinding, polishing, vibratory finishing, abrasive slurries);
— blasting operations (e.g. sand blasting, shot peening);
— chemical finishing (e.g. plating, dipping, degreasing);
— coating (e.g. painting, spraying, powder coating).
The selection depends upon the material, geometry (e.g. size, complexity, accessibility), surface finish
(e.g. roughness, waviness, lay), tolerances, aesthetic and economic considerations.
6.5.2 Machining allowances
Depending on the requirements of an additively manufactured part, it may be necessary to machine one
or several areas to comply with the required tolerances. This typically requires a machining allowance
which comprises at least the maximum possible dimensional deviation.
Machining allowances are to be regarded as a “cutting allowance”, i.e. for machining solids of revolution
or for two-sided machining, allowances shall be applied twice in accordance with ISO 21920-1 or ANSI/
ASME Y14.5.
Consideration should also be given to the fact that, depending on the geometry, additively manufactured
parts may be subject to warpage. An additional machining allowance may be required for this (see
ASTM F3530-22).
7 Inspection and testing
7.1 General
The following aspects may be controlled and documented for quality assurance purposes (e.g. through
controlled procedures and records):
— metallurgical testing;
— mechanical testing;
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
— surface quality inspection;
— geometrical inspection (form, dimension and tolerances);
— non-destructive testing.
NOTE Additional records, not covered in this document:
— machine build log report, see ISO/ASTM 52904;
— powder cycle/reconditioning, see ISO/ASTM 52928;
— equipment maintenance records, see ISO/ASTM TS 52930;
— cleaning lenses/building chamber → quality specification, see ISO/ASTM TS 52930;
— filter (quality, saturation, condensate), see ISO/ASTM TS 52930;
— in-process monitoring (melt pool analysis, etc.), see ISO/ASTM 52920.
7.2 Metallurgical testing
7.2.1 Objective
Numerous methods have been developed in metallography to quantitatively and/or qualitatively
describe structural characteristics in metallic materials, including defects such as pores and cracks.
These can equally be applied to the analysis of test specimens and parts made by PBF to provide
information about manufacturing quality, material characteristics and behaviour. The structure
of a material is characterised by the type, size, shape, distribution and orientation of the structural
components. Numerous metallographic investigations can be carried out by examining the structure
of a polished cross-section of a test specimen or appropriately prepared part with the naked eye, a
magnifying glass or a microscope. While general metallographic procedures described in other
standards are typically sufficient for the preparation of metals produced in laser powder bed fusion,
there are structures and features specific to this production method that occur frequently enough to be
of note.
7.2.2 Test specimen selection, design, and preparation for part characterization
Metallographic characterization of parts produced by powder bed fusion is a common operation,
but there are process and material details that may not be immediately apparent to new users of the
technology. The two fundamental test specimen types that are commonly processed are those cut from
actual parts and those specifically designed to be used for metallographic evaluation.
In the case of test specimens cut from actual parts, a typical goal is to ensure that the test specimen is
free from defects. In the powder bed fusion process, material is formed at the same time as the part,
and an approach akin to that taken in the characterization of cast materials is required, as opposed
to the approach taken in subtractive manufacturing processes where the material properties are
already known. Care shall be taken because many imperfections depend on the specific geometry
that is produced, so it can be difficult to extrapolate material quality characteristics from simple test
specimens to complex parts, even when using the same powder and build parameters. For the purposes
of sectioning the part, the use of either metallographic saws or wire EDM is recommended over
machining, to ensure that the material is not adversely affected during sectioning. This is of particular
concern with softer materials.
The second case of processing parts designed for metallographic characterization allows for substantial
freedom to design the part to fit the need and ease the process of test specimen preparation. A few
considerations for the design of the test specimen geometry are listed in the following:
a) Test specimen size: The test specimen should be sized appropriately to fit in the metallographic
mounting cup or mould or planned to be sectioned so that it will fit. Again, when possible, the parts
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
should be sectioned using a method that does not adversely affect the material. Metallographic
saws or wire EDM are commonly used for this purpose.
b) Location: If the test specimen is cut out of a part, the location should be defined in a drawing of the
part and added to the documentation in the test report.
c) Polished face orientation: The polished face of the part may be in a plane parallel to the build
platform (XY), or in a plane parallel with the build direction (Z), which are often of great importance
for the types of structures that are visible in the test specimen. For the characterization of some
effects, it can be beneficial to introduce a feature in the part to indicate the orientation of the part
within the XY plane as well.
The plane of polishing shall be specified in the quality control plan for the part. If no direction is
specified, then both directions should be evaluated.
d) Surface effects: Often the external surfaces of parts produced in laser powder bed fusion parts are
not representative of the bulk, internal material. Observation of this surface region can or cannot
be the goal of the characterization effort, but users should be aware that characterization efforts in
near surface regions are subject to these effects.
e) Mounting method: If mounting fine structures, such as lattices or parts with thin walls, hot
mounting is not recommended as the pressure that is used during the mounting process can
substantially deform the part.
f) Labelling: In the case where a number of test specimens from a single build is cut, mounted and
polished, it can be beneficial to label directly into the part such that labels are visible during
subsequent steps.
g) Required material response: For example, a part that is used for the characterization of bulk
material density cannot be well suited to determining the level of near surface porosity. It is
recommended to consider the required material response.
h) Thermal treatment: It may be desired to perform thermal post-processing (see 6.3) in addition to
mechanical post-processing. Test specimens shall be subjected to the same post-processing as the
parts they represent.
The test specimen shall be prepared in accordance with a standard specified (e.g. ASTM E3). After the
test specimen is mounted using either a hot mount press or cold mount mould, it is typical to grind and
then polish the test specimen.
After fine polishing, there are several possible subsequent steps. This is the ideal time to measure
bulk porosity in the test specimen by taking a digital photo and processing the image to determine the
relative density, as described in 7.2.3. After this analysis, the test specimen may be chemically etched
to show additional structure and permit a more detailed examination of the metallic structure in PBF.
In most of the cases etching is required to reveal the separate microstructural constituents of a metal
alloy. Various etching techniques exploit the diversity of individual types of grain, e.g. crystallographic
orientation, chemical composition, hardness, chemical resistance. A wide variety of etching techniques
can be used on metallographic specimens.
In certain materials, etching in the as-build condition also exposes features unique to materials
produced by powder bed laser fusion. It is often possible to see evidence of each pass of the laser over
the material. In these materials, it is often possible to see the path of both the bulk scan and the contour
scan, which can be beneficial when diagnosing porosity problems due to insufficient overlap between
those scans.
7.2.3 Test methods, parameters, and test specimens
Refer to ISO/ASTM 52927 for examples of suitable test methods, parameters, and test specimens.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
7.2.4 Chemical analysis
The chemical composition shall be determined using methods stipulated in the material specification.
7.2.5 Metallurgical properties
The grain size shall be measured in at least two orthogonal planes (e.g. horizontal and vertical planes
relative to the build direction) because of the potential for microstructure anisotropy.
7.2.6 Determining the non-metallic inclusion content
Non-metallic inclusion content shall be assessed using a method appropriate for the selected material
(see ISO/ASTM 52927 and the relevant material specification).
7.2.7 Analysis and test report
When analysing metallographic specimens, it is important to be aware of the micro-structural
characteristics created by the layer-on-layer construction process of metal parts made by PBF. The test
report sha
...
SLOVENSKI STANDARD
01-marec-2024
Dodajalna izdelava kovinskih izdelkov - Lastnosti končnih delov - Končna
obdelava, kontrola in preskušanje delov, izdelanih s spajanjem prahu na podlagi
(ISO/ASTM 52908:2023)
Additive manufacturing of metals - Finished Part properties - Post-processing, inspection
and testing of parts produced by powder bed fusion (ISO/ASTM 52908:2023)
Additive Fertigung von Metallen - Eigenschaften von Fertigteilen - Nachbearbeitung,
Inspektion und Prüfung von Bauteilen hergestellt mittels pulverbettbasiertem Schmelzen
(ISO/ASTM 52908:2023)
Fabrication additive de métaux - Propriétés des pièces finies - Post-traitement,
inspection et essais des pièces produites par fusion sur lit de poudre (ISO/ASTM
52908:2023)
Ta slovenski standard je istoveten z: EN ISO/ASTM 52908:2023
ICS:
25.030 3D-tiskanje Additive manufacturing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO/ASTM 52908
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2023
EUROPÄISCHE NORM
ICS 25.030
English Version
Additive manufacturing of metals - Finished Part
properties - Post-processing, inspection and testing of
parts produced by powder bed fusion (ISO/ASTM
52908:2023)
Fabrication additive de métaux - Propriétés des pièces Additive Fertigung von Metallen - Eigenschaften von
finies - Post-traitement, inspection et essais des pièces Fertigteilen - Nachbearbeitung, Inspektion und
produites par fusion sur lit de poudre (ISO/ASTM Prüfung von Bauteilen hergestellt mittels
52908:2023) pulverbettbasiertem Schmelzen (ISO/ASTM
52908:2023)
This European Standard was approved by CEN on 19 November 2023.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO/ASTM 52908:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO/ASTM 52908:2023) has been prepared by Technical Committee ISO/TC 261
"Additive manufacturing" in collaboration with Technical Committee CEN/TC 438 “Additive
Manufacturing” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2024, and conflicting national standards shall be
withdrawn at the latest by May 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/ASTM 52908:2023 has been approved by CEN as EN ISO/ASTM 52908:2023 without
any modification.
INTERNATIONAL ISO/ASTM
STANDARD 52908
First edition
2023-11
Additive manufacturing of metals —
Finished part properties — Post-
processing, inspection and testing of
parts produced by powder bed fusion
Fabrication additive de métaux — Propriétés des pièces finies — Post-
traitement, inspection et essais des pièces produites par fusion sur lit
de poudre
Reference number
ISO/ASTM 52908:2023(E)
© ISO/ASTM International 2023
ISO/ASTM 52908:2023(E)
© ISO/ASTM International 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester. In the United States, such requests should be sent to ASTM International.
ISO copyright office ASTM International
CP 401 • Ch. de Blandonnet 8 100 Barr Harbor Drive, PO Box C700
CH-1214 Vernier, Geneva West Conshohocken, PA 19428-2959, USA
Phone: +41 22 749 01 11 Phone: +610 832 9634
Fax: +610 832 9635
Email: copyright@iso.org Email: khooper@astm.org
Website: www.iso.org Website: www.astm.org
Published in Switzerland
ii
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviations . 2
5 Qualification . 2
5.1 General . 2
5.2 Part validation . 3
5.3 Technical documentation relating to part(s) produced . 3
5.4 Facility documentation . 3
5.4.1 Additive manufacturer documentation requirements . 3
5.4.2 Subcontractor documentation requirements . 3
5.5 Quality assurance documentation . 4
6 Post processing . 4
6.1 General . 4
6.2 Post-build activities . 4
6.3 Thermal treatment . 5
6.3.1 General . 5
6.3.2 Reducing residual stresses . 5
6.3.3 Reducing anisotropy . 5
6.3.4 Prepare material for mechanical post-processing . 5
6.3.5 Densification . 5
6.3.6 Annealing and aging . 5
6.4 Separation from the built platform and support structures . 6
6.5 Surface finishing . 6
6.5.1 Surface finishing operations . 6
6.5.2 Machining allowances . 6
7 Inspection and testing .6
7.1 General . 6
7.2 Metallurgical testing . 7
7.2.1 Objective . 7
7.2.2 Test specimen selection, design, and preparation for part characterization. 7
7.2.3 Test methods, parameters, and test specimens. 8
7.2.4 Chemical analysis . 9
7.2.5 Metallurgical properties . 9
7.2.6 Determining the non-metallic inclusion content . 9
7.2.7 Analysis and test report . 9
7.3 Material testing . 9
7.3.1 General . 9
7.3.2 Orientation in the build space . 10
7.3.3 Test specimen geometry and surface quality . 10
7.3.4 Density (part) . . 10
7.3.5 Archimedean method.12
7.3.6 Image analysis of metallographic specimens .13
7.4 Mechanical testing . 15
7.4.1 Static testing .15
7.4.2 Dynamic testing . 20
7.5 Surface quality inspection . 21
7.6 Geometrical inspection (form, dimension, and tolerances) . 21
7.7 Non-destructive testing . 21
iii
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Bibliography .23
iv
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
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 ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
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 Objective to create a common set
of ISO/ASTM standards on Additive Manufacturing, and 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).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
Introduction
As with conventional manufacturing processes (e.g. casting and milling), metallic parts produced by
additive manufacturing technologies have critical-to-quality characteristics. These characteristics
include density, strength, hardness, surface quality, dimensional accuracy, residual stresses, absence
of cracks, voids, and structural homogeneity, which are typically tested in additively manufactured
components. The quality of additively manufactured components is essential for functional components
produced on an industrial scale. Thus, it is necessary to qualify additive manufacturing processes
according to uniform criteria and to apply standardised in-process and post-process testing.
vi
© ISO/ASTM International 2023 – All rights reserved
INTERNATIONAL STANDARD ISO/ASTM 52908:2023(E)
Additive manufacturing of metals — Finished part
properties — Post-processing, inspection and testing of
parts produced by powder bed fusion
1 Scope
This document specifies requirements for the qualification, quality assurance and post processing for
metal parts made by powder bed fusion.
This document specifies methods and procedures for testing and qualification of various characteristics
of metallic parts made by additive manufacturing powder bed fusion processes, in accordance with
ISO/ASTM 52927, categories H and M.
This document is intended to be used by part providers and/or customers of parts.
This document specifies qualification procedures where appropriate to meet defined quality levels.
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 3369:2006, Impermeable sintered metal materials and hardmetals — Determination of density
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 18265, Metallic materials — Conversion of hardness values
ISO 21920-1, Geometrical product specifications (GPS) — Surface texture: Profile — Part 1: Indication of
surface texture
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
ISO/ASTM 52907, Additive manufacturing — Feedstock materials — Methods to characterize metal
powders
ISO/ASTM 52920, Additive manufacturing — Qualification principles — Requirements for industrial
additive manufacturing processes and production sites
ISO/ASTM 52927, Additive manufacturing — General principles — Main characteristics and corresponding
1)
test methods
2)
ISO/ASTM 52928, Additive manufacturing — Feedstock materials — Powder life cycle management
ISO/ASTM/TS 52930, Additive manufacturing — Qualification principles — Installation, operation and
performance (IQ/OQ/PQ) of PBF-LB equipment
ANSI/ASME Y14.5, Dimensioning and Tolerancing
ASTM B311, Standard Test Method for Density of Powder Metallurgy (PM) Materials Containing Less Than
Two Percent Porosity
1) Under preparation. Stage at the time of publication: ISO/DIS 52927:2023.
2) Under preparation. Stage at the time of publication: ISO/DIS 52928:2023.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
ASTM B962, Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products
Using Archimedes’ Principle
ASTM E8/E8M, Standard Test Methods for Tension Testing of Metallic Materials
DIN 50125, Testing of metallic materials — Tensile test pieces
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
grain size
average grain size in the metallurgical structure when viewed in cross-section
4 Abbreviations
The abbreviations listed in Table 2 are used throughout this document.
Table 2 — Abbreviations
AM additive manufacturing
EDX energy-dispersive X-ray spectroscopy
SEM scanning electron microscope
CAD computer aided design
NDT non-destructive testing
QA quality assurance
COC certificate of conformance
ASL approved supplier list
HIP hot isostatic pressing
EDM electrical discharge machining
PBF powder bed fusion
5 Qualification
5.1 General
The manufacturer shall demonstrate the capability to produce AM parts to the requirements given in
the purchase specification. The inspection and testing described in the following clauses are performed
and assessed using the methods and acceptance criteria stated in the purchase specification.
NOTE Inspection and testing methods are specified at the design stage, as described in ISO/ASTM 52927,
and are in accordance with the relevant standards and regulations that are required for the conformity of that
part.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
5.2 Part validation
Validation that the part produced complies with the requirements of the purchase specification shall be
captured in a qualification record. A typical ‘qualification record’, shall consist of:
— technical documentation relating to part(s) produced;
— facility documentation;
— quality assurance (QA) documentation.
5.3 Technical documentation relating to part(s) produced
The technical documentation relating to part(s) produced shall contain:
— part specification in accordance with ISO/ASTM 52927, which includes inspection methods,
associated plans, acceptance criteria, and representative quality indicators where applicable;
— feedstock specification, test results and declaration of conformity in accordance with
ISO/ASTM 52907;
— material specification (consolidated product material properties specification);
— manufacturing plan (e.g. see ISO/ASTM 52904);
— records of destructive and non-destructive testing;
— inspection record for the part (in accordance with the purchase specification);
— other documentation required by the purchaser, regulation or product standard (e. g. material
identification, labelling, product instructions).
NOTE 1 For some materials, there is a singular specification that controls both feedstock and material
properties, such as metallurgical and mechanical properties.
NOTE 2 Technical specifications for metal powders are addressed in ISO /ASTM 52907.
5.4 Facility documentation
5.4.1 Additive manufacturer documentation requirements
Facility documentation requirements for industrial manufacturing sites are addressed in
ISO/ASTM 52920.
For the purpose of this document, an outline of the relevant manufacturing plant and equipment shall
be provided at the request of the buyer. The outline shall include the major items of equipment used for
post processing, inspection, and testing (including details of geographical location).
The following facility documentation shall be provided:
— records of equipment qualification in accordance with ISO/ASTM TS 52930;
— records of powder lifecycle management in accordance with ISO/ASTM 52928.
The requirements in this subclause are met where a quality management system is in place (see 5.5).
5.4.2 Subcontractor documentation requirements
Where the manufacturer subcontracts post-processing and/or testing activities, the manufacturer
shall be able to indicate the conditions under which these activities are subcontracted and shall provide
a purchase specification for the operations involved.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
The manufacturer shall assess and approve the subcontractors for their capability to perform the
subcontracted activity to the required quality level.
5.5 Quality assurance documentation
General QA documentation requirements are met by introducing a quality management system (e.g.
ISO 9001 or ISO 13485).
Additive manufacturing QA documentation requirements shall be in accordance with ISO/ASTM 52920.
6 Post processing
6.1 General
Post-processing consists of activities performed after the completion of a build cycle but prior to final
inspection activities.
NOTE Intermediate inspection can be performed between post-processing activities.
Post-processing operations are typically performed to achieve the desired material properties, final
geometry and surface finish, and can include the following steps:
— post-build activities (e.g. cool down, declamping, removal from the AM machine, part cleaning);
— thermal treatment;
— separation from the build platform and support structures;
— surface finishing.
At the post-processing stage there are also several system-based operations performed (i.e. not related
to the AM part) to prepare for subsequent builds. These activities are covered within other standards
and include:
— recovery and reprocessing of unfused powder (in accordance with ISO/ASTM 52928);
— AM equipment cleaning and maintenance (in accordance with ISO/ASTM 52920).
6.2 Post-build activities
Following successful completion of the build, the chamber is allowed to cool and unfused powder is
recovered from the build chamber. Once the build chamber is opened, the build platform fasteners
can be removed, and care shall be taken to avoid deflection, which could induce cracking, due to the
build-up of any residual stresses within the build. (see ASTM F3530-22)
Once the build assembly is removed from the AM machine, it can be cleaned and visually inspected
(e.g. for imperfections, discolouration, separation from support structures). Loose powder that remains
on the build assembly after exposure to atmosphere (i.e. no longer within an inert environment) can
be removed by various methods (e.g. compressed gas, brushing, vacuum, sonic or ultrasonic cleaning
methods). Loose powder removed at this stage shall be considered to be waste powder and disposed of
safely.
For some non-reactive materials, loose powder that is removed within a controlled environment (e.g.
glovebox, automatic depowdering unit), can also be reused where allowed by the manufacturer’s
procedures, subject to contamination and traceability controls.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
6.3 Thermal treatment
6.3.1 General
Although it is not mandatory to apply any thermal treatment to additively manufactured parts, the
following points should be considered.
NOTE Thermal treatment is executed after it is ensured that all powder located in internal channels is
removed.
6.3.2 Reducing residual stresses
The build-up of successive layers with rapid heating and cooling generates residual stresses in
the component, which can lead to distortion. Where used, support structures help to minimise this
distortion by providing stiffness within the build assembly to resist deflection due to these residual
stresses. Therefore, the build assembly is typically stress relieved prior to the removal of any support
structures, although this is not mandatory. The release of thermal stresses can lead to distortion, over
a short or prolonged period of time. Furthermore, local stress peaks can occur in the part, which can
significantly reduce fatigue strength and lead to premature cracking. Stress-relief reduces stresses in
the component in a controlled manner after manufacture, thereby preventing distortion.
6.3.3 Reducing anisotropy
The as-built part can exhibit anisotropy, which may be normalised to minimise the orientation
and location dependence on the mechanical properties of the formed material and achieve the final
mechanical property requirements.
NOTE ISO/ASTM 52909 includes supplementary guidelines for the evaluation of finished part properties,
including orientation and location dependence, for metal parts produced by powder bed fusion.
6.3.4 Prepare material for mechanical post-processing
Processes such as annealing can reduce the hardness of the as-built material to facilitate subsequent
machining operations. Annealing, followed by ageing, can reduce intergranular corrosion and cracking.
6.3.5 Densification
Hot isostatic pressing (HIP) can improve material properties through the reduction of porosity and
anisotropy.
NOTE 1 ASTM A 1080/A 1080M provides a standard practice for hot isostatic pressing of steels, stainless
steels and related alloys.
The thermal treatment specified depends on the material and desired mechanical properties, as defined
within the material specification and agreed between manufacturer and purchaser.
NOTE 2 ASTM F 3301a includes details of thermal treatments for various metals produced by powder bed
fusion.
Test specimens used for destructive testing shall be representative of the part and therefore be
subjected to the same thermal post-processing operations as the part they represent.
6.3.6 Annealing and aging
Annealing, followed by ageing, can also enable grain boundary carbides to enter into solution and thus
prevent unacceptable grain boundary carbide precipitation, which can lead to intergranular corrosion
and cracking.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
6.4 Separation from the built platform and support structures
Various items can be present within the build assembly, which require separation from the build
platform, from support structure and/or from other items (e.g. the part, test specimens). A suitable
method of separation shall be specified in the manufacturing plan, such that separation does not have
a detrimental effect on the integrity of the part or test specimens, e.g. wire EDM, metallographic saw,
breaking parts off by hand.
Separation from the build platform should be studied to determine the best method and when to be
performed (see 6.3.2).
6.5 Surface finishing
6.5.1 Surface finishing operations
Suitable finishing operations may be selected by the manufacturer and shall be defined within the
manufacturing plan, to achieve the final geometry and surface finish requirements, specified in the
design.
NOTE Numerous finishing operations are available, examples of which are listed below:
— machining (e.g. turning, drilling, milling);
— electrical discharge machining (EDM);
— abrasive operations (e.g. grinding, polishing, vibratory finishing, abrasive slurries);
— blasting operations (e.g. sand blasting, shot peening);
— chemical finishing (e.g. plating, dipping, degreasing);
— coating (e.g. painting, spraying, powder coating).
The selection depends upon the material, geometry (e.g. size, complexity, accessibility), surface finish
(e.g. roughness, waviness, lay), tolerances, aesthetic and economic considerations.
6.5.2 Machining allowances
Depending on the requirements of an additively manufactured part, it may be necessary to machine one
or several areas to comply with the required tolerances. This typically requires a machining allowance
which comprises at least the maximum possible dimensional deviation.
Machining allowances are to be regarded as a “cutting allowance”, i.e. for machining solids of revolution
or for two-sided machining, allowances shall be applied twice in accordance with ISO 21920-1 or ANSI/
ASME Y14.5.
Consideration should also be given to the fact that, depending on the geometry, additively manufactured
parts may be subject to warpage. An additional machining allowance may be required for this (see
ASTM F3530-22).
7 Inspection and testing
7.1 General
The following aspects may be controlled and documented for quality assurance purposes (e.g. through
controlled procedures and records):
— metallurgical testing;
— mechanical testing;
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
— surface quality inspection;
— geometrical inspection (form, dimension and tolerances);
— non-destructive testing.
NOTE Additional records, not covered in this document:
— machine build log report, see ISO/ASTM 52904;
— powder cycle/reconditioning, see ISO/ASTM 52928;
— equipment maintenance records, see ISO/ASTM TS 52930;
— cleaning lenses/building chamber → quality specification, see ISO/ASTM TS 52930;
— filter (quality, saturation, condensate), see ISO/ASTM TS 52930;
— in-process monitoring (melt pool analysis, etc.), see ISO/ASTM 52920.
7.2 Metallurgical testing
7.2.1 Objective
Numerous methods have been developed in metallography to quantitatively and/or qualitatively
describe structural characteristics in metallic materials, including defects such as pores and cracks.
These can equally be applied to the analysis of test specimens and parts made by PBF to provide
information about manufacturing quality, material characteristics and behaviour. The structure
of a material is characterised by the type, size, shape, distribution and orientation of the structural
components. Numerous metallographic investigations can be carried out by examining the structure
of a polished cross-section of a test specimen or appropriately prepared part with the naked eye, a
magnifying glass or a microscope. While general metallographic procedures described in other
standards are typically sufficient for the preparation of metals produced in laser powder bed fusion,
there are structures and features specific to this production method that occur frequently enough to be
of note.
7.2.2 Test specimen selection, design, and preparation for part characterization
Metallographic characterization of parts produced by powder bed fusion is a common operation,
but there are process and material details that may not be immediately apparent to new users of the
technology. The two fundamental test specimen types that are commonly processed are those cut from
actual parts and those specifically designed to be used for metallographic evaluation.
In the case of test specimens cut from actual parts, a typical goal is to ensure that the test specimen is
free from defects. In the powder bed fusion process, material is formed at the same time as the part,
and an approach akin to that taken in the characterization of cast materials is required, as opposed
to the approach taken in subtractive manufacturing processes where the material properties are
already known. Care shall be taken because many imperfections depend on the specific geometry
that is produced, so it can be difficult to extrapolate material quality characteristics from simple test
specimens to complex parts, even when using the same powder and build parameters. For the purposes
of sectioning the part, the use of either metallographic saws or wire EDM is recommended over
machining, to ensure that the material is not adversely affected during sectioning. This is of particular
concern with softer materials.
The second case of processing parts designed for metallographic characterization allows for substantial
freedom to design the part to fit the need and ease the process of test specimen preparation. A few
considerations for the design of the test specimen geometry are listed in the following:
a) Test specimen size: The test specimen should be sized appropriately to fit in the metallographic
mounting cup or mould or planned to be sectioned so that it will fit. Again, when possible, the parts
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
should be sectioned using a method that does not adversely affect the material. Metallographic
saws or wire EDM are commonly used for this purpose.
b) Location: If the test specimen is cut out of a part, the location should be defined in a drawing of the
part and added to the documentation in the test report.
c) Polished face orientation: The polished face of the part may be in a plane parallel to the build
platform (XY), or in a plane parallel with the build direction (Z), which are often of great importance
for the types of structures that are visible in the test specimen. For the characterization of some
effects, it can be beneficial to introduce a feature in the part to indicate the orientation of the part
within the XY plane as well.
The plane of polishing shall be specified in the quality control plan for the part. If no direction is
specified, then both directions should be evaluated.
d) Surface effects: Often the external surfaces of parts produced in laser powder bed fusion parts are
not representative of the bulk, internal material. Observation of this surface region can or cannot
be the goal of the characterization effort, but users should be aware that characterization efforts in
near surface regions are subject to these effects.
e) Mounting method: If mounting fine structures, such as lattices or parts with thin walls, hot
mounting is not recommended as the pressure that is used during the mounting process can
substantially deform the part.
f) Labelling: In the case where a number of test specimens from a single build is cut, mounted and
polished, it can be beneficial to label directly into the part such that labels are visible during
subsequent steps.
g) Required material response: For example, a part that is used for the characterization of bulk
material density cannot be well suited to determining the level of near surface porosity. It is
recommended to consider the required material response.
h) Thermal treatment: It may be desired to perform thermal post-processing (see 6.3) in addition to
mechanical post-processing. Test specimens shall be subjected to the same post-processing as the
parts they represent.
The test specimen shall be prepared in accordance with a standard specified (e.g. ASTM E3). After the
test specimen is mounted using either a hot mount press or cold mount mould, it is typical to grind and
then polish the test specimen.
After fine polishing, there are several possible subsequent steps. This is the ideal time to measure
bulk porosity in the test specimen by taking a digital photo and processing the image to determine the
relative density, as described in 7.2.3. After this analysis, the test specimen may be chemically etched
to show additional structure and permit a more detailed examination of the metallic structure in PBF.
In most of the cases etching is required to reveal the separate microstructural constituents of a metal
alloy. Various etching techniques exploit the diversity of individual types of grain, e.g. crystallographic
orientation, chemical composition, hardness, chemical resistance. A wide variety of etching techniques
can be used on metallographic specimens.
In certain materials, etching in the as-build condition also exposes features unique to materials
produced by powder bed laser fusion. It is often possible to see evidence of each pass of the laser over
the material. In these materials, it is often possible to see the path of both the bulk scan and the contour
scan, which can be beneficial when diagnosing porosity problems due to insufficient overlap between
those scans.
7.2.3 Test methods, parameters, and test specimens
Refer to ISO/ASTM 52927 for examples of suitable test methods, parameters, and test specimens.
© ISO/ASTM International 2023 – All rights reserved
ISO/ASTM 52908:2023(E)
7.2.4 Chemical analysis
The chemical composition shall be determined using methods stipulated in the material specification.
7.2.5 Metallurgical properties
The grain size shall be measured in at least two orthogonal planes (e.g. horizontal and vertical planes
relative to the build direction) because of the potential for microstructure anisotropy.
7.2.6 Determining the non-metallic inclusion content
Non-metallic inclusion content shall be assessed using a method appropriate for the selected material
(see ISO/ASTM 52927 and the relevant material specification).
7.2.7 Analysis and test report
When analysing metallographic specimens, it is important to be aware of the micro-structural
characteristics created by the layer-on-layer construction process of metal parts made by PBF. The test
report shall
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