ASTM F3335-20
(Guide)Standard Guide for Assessing the Removal of Additive Manufacturing Residues in Medical Devices Fabricated by Powder Bed Fusion
Standard Guide for Assessing the Removal of Additive Manufacturing Residues in Medical Devices Fabricated by Powder Bed Fusion
SIGNIFICANCE AND USE
5.1 Materials used in medical devices are selected in part for their biocompatibility, meaning that they have been demonstrated to have an acceptable biological response for the intended application. During manufacturing, most devices are exposed to a variety of processing steps and materials that have the potential to adversely affect the inherent biocompatibility of the device if they are not adequately removed prior to use.
Note 1: For a fine powder, depending upon application, a new biological risk assessment may be required.
5.2 In additive manufacturing, components are in most cases built layer-by-layer, allowing unprecedented freedom to design complex devices. This makes it possible to build devices that are very difficult to clean, such as topological optimized parts, small internal channels, lattice structures, and especially reticulated porous structures for bone ingrowth and fixation.
5.3 Powdered fusion AM presents additional challenges. Components come out of the build volume with residual powder filling all open spaces within the device. The majority of the excess powder is typically removed by a combination of vibratory shaking, blowing with compressed gas, vacuuming, and ultrasonic cleaning in a solvent. However, the particles are typically very small and can become lodged in internal features such as pores, making removal difficult. Furthermore, particles that were immediately adjacent to the component during manufacturing can be partially sintered to the surface. Those particles can be extremely difficult to remove, are indistinguishable from loose particles when observed by most techniques, and may be at risk of detaching during the intended use of the device.
5.4 This guide provides specific evaluation techniques for measuring the effectiveness of residue removal processes, as they should be able to yield consistent results that meet the respective performance and cleanliness criteria for the intended use.
SCOPE
1.1 This standard provides guidance for assessing the manufacturing material residues in medical devices fabricated using additive manufacturing (AM) techniques, specifically, from powder bed fusion AM technologies.
1.1.1 Some of the techniques discussed in this guide may be applicable to devices fabricated by other types of AM equipment (e.g., stereolithography). Given each AM technique’s characteristics and post-processing challenges, there could be additional risks or considerations associated with some AM techniques or materials that are not addressed by this guide.
1.2 This guide covers several qualitative and quantitative assessments of the presence and amount of residue remaining in or obtained by extraction in aqueous or organic solvents from powder bed fusion AM medical components.
1.2.1 This guide identifies techniques to qualitatively determine the presence of residue and a technique to quantitatively assess it. It does not set acceptance criteria or acceptable limits for residues remaining in built parts. These methods are not the only methods to determine the presence or quantity of residual material in additive manufactured medical components.
1.3 This guide pertains to devices in their finished state (after post-processing and subsequent manufacturing processes), as applicable. This guide may also be used to evaluate the effectiveness of cleaning processes between critical steps in the manufacturing process, to ensure minimal AM residue remains for cleaning processes downstream.
1.4 This guide is not intended to evaluate the residue level in medical components that have been cleaned for reuse.
1.5 Different cleaning methods, including high energy processes, can potentially damage small structures in AM parts. This guide does not address measurement or mitigation of this risk.
1.6 This guide does not address the manufacturing occupational health issues of working with small particles (e.g., breathing hazards).
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General Information
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Standards Content (Sample)
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: F3335 − 20
Standard Guide for
Assessing the Removal of Additive Manufacturing Residues
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in Medical Devices Fabricated by Powder Bed Fusion
This standard is issued under the fixed designation F3335; 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 1.7 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 Thisstandardprovidesguidanceforassessingthemanu-
standard.
facturing material residues in medical devices fabricated using
additive manufacturing (AM) techniques, specifically, from
1.8 This standard does not purport to address all of the
powder bed fusion AM technologies.
safety concerns, if any, associated with its use. It is the
1.1.1 Some of the techniques discussed in this guide may be
responsibility of the user of this standard to establish appro-
applicable to devices fabricated by other types of AM equip-
priate safety, health, and environmental practices and deter-
ment (e.g., stereolithography). Given each AM technique’s
mine the applicability of regulatory limitations prior to use.
characteristics and post-processing challenges, there could be
1.9 This international standard was developed in accor-
additional risks or considerations associated with some AM
dance with internationally recognized principles on standard-
techniques or materials that are not addressed by this guide.
ization established in the Decision on Principles for the
1.2 This guide covers several qualitative and quantitative
Development of International Standards, Guides and Recom-
assessments of the presence and amount of residue remaining
mendations issued by the World Trade Organization Technical
in or obtained by extraction in aqueous or organic solvents
Barriers to Trade (TBT) Committee.
from powder bed fusion AM medical components.
1.2.1 This guide identifies techniques to qualitatively deter-
2. Referenced Documents
mine the presence of residue and a technique to quantitatively
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assess it. It does not set acceptance criteria or acceptable limits
2.1 ASTM Standards:
for residues remaining in built parts.These methods are not the
F311 Practice for Processing Aerospace Liquid Samples for
only methods to determine the presence or quantity of residual
Particulate ContaminationAnalysis Using Membrane Fil-
material in additive manufactured medical components.
ters
F1877 Practice for Characterization of Particles
1.3 This guide pertains to devices in their finished state
F1903 Practice for Testing for Cellular Responses to Par-
(after post-processing and subsequent manufacturing
processes), as applicable. This guide may also be used to ticles in vitro
evaluate the effectiveness of cleaning processes between criti- F1904 Practice for Testing the Biological Responses to
cal steps in the manufacturing process, to ensure minimal AM
Particles in vivo
residue remains for cleaning processes downstream. F2459 Test Method for Extracting Residue from Metallic
Medical Components and Quantifying via Gravimetric
1.4 This guide is not intended to evaluate the residue level
Analysis
in medical components that have been cleaned for reuse.
F2847 Practice for Reporting and Assessment of Residues
1.5 Different cleaning methods, including high energy
on Single-Use Implants and Single-Use Sterile Instru-
processes,canpotentiallydamagesmallstructuresinAMparts.
ments
This guide does not address measurement or mitigation of this
F3127 GuideforValidatingCleaningProcessesUsedDuring
risk.
the Manufacture of Medical Devices
1.6 This guide does not address the manufacturing occupa-
G131 PracticeforCleaningofMaterialsandComponentsby
tional health issues of working with small particles (e.g.,
Ultrasonic Techniques
breathing hazards).
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This test method is under the jurisdiction ofASTM Committee F04 on Medical
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and Surgical Materials and Devices and is the direct responsibility of Subcommittee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
F04.15 on Material Test Methods. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 1, 2020. Published February 2020. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F3335-20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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