ASTM F3456-22

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F3456 − 22
Standard Guide for
Powder Reuse Schema in Powder Bed Fusion Processes for
Medical Applications for Additive Manufacturing Feedstock
Materials
This standard is issued under the fixed designation F3456; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ASTM Standards:
B213 Test Methods for Flow Rate of Metal Powders Using
1.1 This guide provides a concise approach for users of
the Hall Flowmeter Funnel
powder bed fusion (PBF) processes to communicate the
B214 Test Method for Sieve Analysis of Metal Powders
method(s) in which feedstock powders are controlled through-
B215 Practices for Sampling Metal Powders
out the feedstock lifecycle.
B822 Test Method for Particle Size Distribution of Metal
1.1.1 Regulatory bodies may require descriptions of used
Powders and Related Compounds by Light Scattering
powder reuse schemes in a submission. This is because a
B964 Test Methods for Flow Rate of Metal Powders Using
medical device’s performance can be affected by the condition
the Carney Funnel
of the powder feedstock and current regulations are not
2.3 ANSI/AAMI/ISO Standard:
prescriptive to powder.
ANSI/AAMI/ISO 13485 Medical devices — Quality man-
1.1.2 This guide is intended for users of both polymer and
agementsystems—Requirementsforregulatorypurposes
metal feedstock powders.
2.4 U.S. Food and Drug Administration:
1.2 This guide does not cover powder specifications, recy-
21 CFR 820.60 Quality System Regulation — Identification
cling strategy, blending processes, lot control, or address
contamination prevention.
3. Terminology
1.3 This standard does not purport to address all of the
3.1 Definitions:
safety concerns, if any, associated with its use. It is the
3.1.1 Terminology relating to additive manufacturing in
responsibility of the user of this standard to establish appro-
Terminology ISO/ASTM 52900 shall apply.
priate safety, health, and environmental practices and deter-
3.2 Definitions:
mine the applicability of regulatory limitations prior to use.
3.2.1 overflow powder, n—excess powder that does not
1.4 This international standard was developed in accor-
remain in the build volume, but instead is deposited into the
dance with internationally recognized principles on standard-
overflow region of an additive manufacturing machine.
ization established in the Decision on Principles for the
3.2.1.1 Discussion—Because of its exposure to the build
Development of International Standards, Guides and Recom-
volumeandpreviouslyconsolidatedmaterial,overflowpowder
mendations issued by the World Trade Organization Technical
is considered used powder in the context of reuse.
Barriers to Trade (TBT) Committee.
3.2.2 powder lot, n—a lot as defined in ISO/ASTM 52900,
2. Referenced Documents
where the feedstock is powder.
2 3.2.2.1 Discussion—The machine user may develop addi-
2.1 ISO/ASTM Standards:
tional naming/labeling conventions if a single powder lot is
52900 Additive manufacturing — General principles —
permanently subdivided between different machines or to keep
Fundamentals and Vocabulary
track of how many times the powder has been reused. The
machine user can choose the exact naming convention pro-
1 vided the convention maintains appropriate traceability and
This guide is under the jurisdiction of ASTM Committee F42 on Additive
Manufacturing Technologies and is the direct responsibility of Subcommittee does not create ambiguity in the description of the schema.
F42.07 on Applications.
Current edition approved April 1, 2022. Published May 2022. DOI: 10.1520/
F3456-22.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
Standards volume information, refer to the standard’s Document Summary page on Available from U.S. Food and Drug Administration (FDA), 10903 New
the ASTM website. Hampshire Ave., Silver Spring, MD 20993, http://www.fda.gov.
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F3456 − 22
3.2.3 refreshed powder batch, n—powder blend of used and 5.3 Powder Storage—Whenever powder is stored or
virgin powder. handled external to the machine, procedures should be vali-
3.2.3.1 Discussion—If a strategy of refreshing a batch of dated that prevent feedstock contamination during blending,
used powder with virgin powder is adopted, the user’s naming sieving, and container transfer.
convention must retain traceability for both sources of powder
5.4 Used Powder—Used powder can have different process
and not create ambiguity. Additionally, the exact ratio of the
exposurelevels(forexample,proximitytoenergysource,build
blend is left to the machine user.
chamber environment, overflow bins) that can affect powder
properties. The different exposure levels from part cake,
4. Significance and Use
overflow, and powder feed bin may result in material that has
4.1 In PBF systems, powder is often reused to increase
different thermal history and should be assessed by the ma-
feedstock efficiency by reducing waste. While in many appli-
chine user to ensure the different conditions do not adversely
cations the customer can rely on the manufacturer’s validation
affect final product performance.
and verification activities to ensure their PBF process produces
6. Powder Reuse Schema
parts of the appropriate quality, some medical device regula-
tory bodies ask for the powder reuse schema to ensure that any
6.1 No refreshing with virgin powder.
effect of powder reuse on final device performance is as-
6.1.1 No Reuse—Virgin powder is loaded into the PBF
sessed. The intention of this guide is to provide
powder feed bin which produces used powder during the build
manufacturers, customers, and regulatory bodies concise ter-
cycle(s). The used powder is then marked as unsuitable for
minology to describe powder feedstock reuse schema for PBF
reuse or discarded, or both as shown in Fig. 1.
using metal or polymer feedstock.Additionally, a well-defined
6.1.2 Discrete Reuse—Virgin powder is loaded into the PBF
powder reuse schema may reduce the risk of feedstock
powder feed bin. Used powder from all sources (part cake,
contamination and associated defects within the manufactur-
overflow, etc.) is reclaimed and stored in accordance with
er’s quality management system. Each schema represents a
standard storage procedures.When there is no longer sufficient
broad reuse strategy and is intended to be used as the starting
virgin powder feedstock to replenish the bin with enough
point in describing a powder strategy to customers and
powder to complete an additional build cycle, the used powder
regulatory bodies. While the focus of this guide is for medical
issieved,blendedwiththeremainingmaterialfromthepowder
applications, the schema referenced can be used for non-
feed bin, and loaded back into the PBF powder feed bin. Each
medical applications.
time the used powder batches are processed in a build cycle a
sequential designation (“n”in Fig. 2) is applied to track the
5. General Considerations
number of times the powder has been reused. The process
5.1 Traceability—Traceability/naming of materials is a re- repeats until the powder lot is exhausted, there is no long
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