Technical Considerations for 
Additive Manufactured Medical 
Devices 
Guidance for Industry and  
Food and Drug Administration Staff  
Document issued on December 5, 2017.  
The draft of this document was issued on May 10, 2016. 
For questions about this document regarding CDRH-regulated devices, contact the Division of 
Applied Mechanics at (301) 796-2501, the Division of Orthopedic Devices at (301) 796-5650, 
or Matthew Di Prima, Ph.D. at (301) 796-2507 or by email matthew.diprima@fda.hhs.gov.   
For questions about this document regarding CBER-regulated devices, contact the Office of 
Communication, Outreach, and Development (OCOD) at 1-800-835-4709 or 240-402-8010.  
 
 
 
 
 
 
 
 
 
 
 
 
 
     U.S. Department of Health and Human 
Services 
  Food and Drug Administration 
Center for Devices and Radiological Health 
Center for Biologics Evaluation and Research 
  Contains Nonbinding Recommendations 
 
 
Preface 
Public Comment 
You may submit electronic comments and suggestions at any time for Agency consideration to 
http://www.regulations.gov .  Submit written comments to the Dockets Management Staff, 
Food and Drug Administration, 5630 Fishers Lane, Room 1061, (HFA-305), Rockville, MD 
20852.  Identify all comments with the docket number FDA-2016-D-1210. Comments may not 
be acted upon by the Agency until the document is next revised or updated. 
Additional Copies 
CDRH 
Additional copies are available from the Internet. You may also send an e-mail request to 
CDRH-Guidance@fda.hhs.gov to receive a copy of the guidance.  Please use the document 
number 1400002 to identify the guidance you are requesting. 
CBER 
Additional copies are available from the Center for Biologics Evaluation and Research 
(CBER)), Office of Communication, Outreach, and Development (OCOD), 10903 New 
Hampshire Ave., WO71, Room 3128, Silver Spring, MD 2090320903, or by calling 1-800-
835-4709 or 240-402-8010, by email, ocod@fda.hhs.gov, or from the Internet at  
http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInform
ation/Guidances/default.htm.   Contains Nonbinding Recommendations 
 
Table of Contents 
I.  Introduction and Scope..................................................................................................................................1
II.  Background ....................................................................................................................................................3
III.  Overview...................................................................................................................................................4
IV. Definitions.................................................................................................................................................5
V.  Design and Manufacturing Process Considerations .......................................................................................6
A.  Overall Device Design...............................................................................................................8
B.  Patient-Matched Device Design.................................................................................................8
C.  Software Workflow ..................................................................................................................11
(1)  File Format Conversions ...................................................................................................11
(2)  Digital Device Design to Physical Device ..........................................................................12
(3)  Validating and Automating Software Processes ..............................................................15
D.  Material Controls ......................................................................................................................15
(1)  Starting Material ...............................................................................................................15
(2)  Material Reuse..................................................................................................................16
E.  Post-Processing ........................................................................................................................17
F.  Process Validation and Acceptance Activities .........................................................................17
(1)  Process Validation ............................................................................................................18
(2)  Revalidation ......................................................................................................................19
(3)  Acceptance Activities ........................................................................................................20
(4)  Test Coupons ....................................................................................................................20
G.  Quality Data .............................................................................................................................21
VI.  Device Testing Considerations ................................................................................................................ 21
A.  Device Description ...................................................................................................................22
B.  Mechanical Testing ..................................................................................................................22
C.  Dimensional Measurements .....................................................................................................23
D.  Material Characterization .........................................................................................................24
(1)  Material Chemistry ...........................................................................................................24
(2)  Material Physical Properties .............................................................................................25
E.  Removing Manufacturing Material Residues and Sterilization ................................................25
F.  Biocompatibility .......................................................................................................................27
VII.  Labeling ................................................................................................................................................... 27 Contains Nonbinding Recommendations 
 
Technical Considerations for 
Additive Manufactured Medical 
Devices 
Guidance for Industry and  
Food and Drug Administration Staff  
 
This guidance represents the current thinking of the Food and Drug Administration (FDA 
or Agency) on this topic.  It does not establish any rights for any person and is not binding 
on FDA or the public.  You can use an alternative approach if it satisfies the requirements 
of the applicable statutes and regulations.  To discuss an alternative approach, contact the 
FDA staff or Office responsible for this guidance as listed on the title page.   
I.  Introduction and Scope 
FDA has developed this guidance to provide the Agencys initial thinking on technical 
considerations specific to devices using additive manufacturing, the broad category of 
manufacturing encompassing 3-dimensional (3D) printing.  Additive manufacturing (AM) is 
a process that builds an object by sequentially building 2-dimensional (2D) layers and joining 
each to the layer below, allowing device manufacturers to rapidly produce alternative designs 
without the need for retooling and to create complex devices built as a single piece.  Rapid 
technological advancements and increased availability of AM fabrication equipment are 
encouraging increased investment in the technology and its increased use by the medical 
device industry.  The purpose of this guidance is to outline technical considerations 
associated with AM processes, and recommendations for testing and characterization for 
devices that include at least one additively manufactured component or additively fabricated 
step. 
This guidance is broadly organized into two topic areas: Design and Manufacturing 
Considerations (Section V) and Device Testing Considerations (Section VI).  The Design and 
Manufacturing Considerations section provides technical considerations that should be 
addressed as part of fulfilling Quality System (QS) requirements for your device, as 
determined by the regulatory classification of your device and/or regulation to which your 
device is subject, if applicable.  While this guidance includes manufacturing considerations, 
it is not intended to comprehensively address all considerations or regulatory requirements to 
establish a quality system for the manufacturing of your device.  The Device Testing 
Consideration section describes the type of information that should be provided in premarket 
  1 
  Contains Nonbinding Recommendations 
 
notification submissions (510(k)), premarket approval (PMA) applications, humanitarian 
device exemption (HDE) applications, De Novo requests and investigational device 
exemption (IDE) applications for an AM device.  The type of premarket submission that is 
required for your AM device is determined by the regulatory classification of your device.  
Questions regarding the regulatory status or requirements for specific devices, products, or 
entities should be addressed to the appropriate review branches through the Division for 
Industry and Consumer Education (DICE@fda.hhs.gov). 
For devices manufactured using AM, the recommendations in this guidance supplement any 
device-specific recommendations outlined in existing guidance documents or applicable 
FDA-recognized consensus standards.  Point-of-care device manufacturing may raise 
additional technical considerations that are not addressed in this document.  In addition, this 
guidance does not address the use or incorporation of biological, cellular, or tissue-based 
products in AM.  Biological, cellular or tissue-based products manufactured using AM 
technology may necessitate additional regulatory and manufacturing process considerations 
and/or different regulatory pathways.  Therefore, AM questions pertaining to biologics, cells 
or tissue products should be directed to the Center for Biologics Evaluation and Research 
(CBER).  Specific questions regarding jurisdiction over a combination product should be 
directed to the Office of Combination Products (OCP) at 301-427-1934 or 
combination@fda.gov.  
This guidance is a leapfrog guidance, a type of guidance that serves as a mechanism by 
which the Agency can share initial thoughts regarding emerging technologies that are likely 
to be of public health importance early in product development.  This leapfrog guidance 
represents the Agency's initial thinking and our recommendations may change as more 
information becomes available.  The Agency encourages manufacturers to engage with the 
Center for Devices and Radiological Health (CDRH) or CBER through the Pre-Submission 
process to obtain more detailed feedback for Additively Manufactured medical devices.  For 
more information on Pre-Submissions, please see Requests for Feedback on Medical Device 
Submissions: The Pre-Submission Program and Meetings with FDA Staff - Guidance for 
Industry and Food and Drug Administration Staff.1  
For the current edition of the FDA-recognized standards referenced in this document, see the 
FDA-Recognized Consensus Standards Database Website.2   
FDA's guidance documents, including this guidance, do not establish legally enforceable 
responsibilities.  Instead, guidances describe the Agencys current thinking on a topic and 
should be viewed only as recommendations, unless specific regulatory or statutory 
requirements are cited.  The use of the word should in Agency guidance means that 
something is suggested or recommended, but not required. 
                                                           
 
1http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM31
1176.pdf  
2 http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/search.cfm  
  2 
  Contains Nonbinding Recommendations 
II. Background
AM is a rapidly growing technology that is frequently used for product research and 
development in many industries, and for commercial production in some industries (e.g., 
aerospace, medical devices).  While many AM technologies exist, at the time of publication 
of this guidance, the most commonly used technologies in medical devices are powder bed 
fusion, stereolithography, fused filament fabrication, and liquid-based extrusion.  Powder bed 
fusion systems rely on an energy source (laser or electron beam) to selectively melt or sinter 
a layer of powder, either a metal or polymer, which is then refreshed to create the next layer.  
Stereolithography systems use a vat of liquid material that is selectively cured using light, 
either through a laser or projection system, and create new layers by moving the build 
surface.  Fused filament fabrication systems melt a solid filament at the point of deposition, 
after which the material solidifies in place, and new layers are created by moving the build 
surface away from the heat source.  Liquid-based extrusion systems eject a liquid, which then 
solidifies (method of solidification could include light exposure, solvent evaporation, or other 
chemical process), and new layers are created by moving the build platform away from the 
deposition tip. 
For medical devices, AM has the advantage of facilitating the creation of anatomically-
matched devices and surgical instrumentation (called patient-matched devices) by using a 
patients own medical imaging.  Another advantage is the ease in fabricating complex 
geometric structures, allowing the creation of engineered porous structures, tortuous internal 
channels, and internal support structures that would not be easily possible using traditional 
(non-additive) manufacturing approaches.  However, the unique aspects of the AM process, 
such as the layer-wise fabrication process, and relative lack of experience and clinical history 
of with respect to devices manufactured using AM techniques, pose challenges in 
determining optimal characterization and assessment methods for the final finished device, as 
well as optimal process validation and acceptance methods for these devices.  The FDA held 
a public workshop entitled Additive Manufacturing of Medical Devices: An Interactive 
Discussion on the Technical Considerations of 3D Printing on October 8-9, 2014, to discuss 
these challenges and obtain initial stakeholder input. 3 
The workshop provided a forum for medical device manufacturers, AM companies, and 
academia to discuss technical considerations for AM medical devices.  It focused on five 
broad themes:  (1) materials; (2) design, printing, and post-printing validation; (3) printing 
characteristics and parameters; (4) physical and mechanical assessment of final devices; and 
(5) biological considerations of final devices, including cleaning, sterility, and 
biocompatibility.  A variety of different types of materials can be used in additive 
manufacturing.  Workshop participants noted that material control is an important aspect to 
ensure successful fabrication, and that final device performance is tied to the material, 
3 http://wayback.archive-
it.org/7993/20170111083117/http://www.fda.gov/MedicalDevices/NewsEvents/WorkshopsConferences/ucm39
7324.htm 
3  Contains Nonbinding Recommendations 
 
machine, and post-printing processes.  The interaction between the material and machine was 
also discussed in the process validation session, and the need for a robust process validation 
and acceptance protocol appropriate to the risk profile of the final device was identified.  AM 
design procedures were also discussed, and the importance of having a good understanding 
of the processes and limits in the design phase was identified.  There was general agreement 
that printing and process parameters should be captured and validated, which can include 
individual machine validations.  The discussion on the physical and mechanical assessment 
focused heavily on the validation of the process and the acceptance criteria for devices and 
components after post-processing.  The discussion on the biological considerations revealed 
that there is a concern across the community regarding how to achieve adequate cleaning, 
sterility, and biocompatibility of an AM device.  Specifically, the challenge of assessing and 
verifying these issues in porous or internally complex devices was discussed.  The feedback 
obtained at the workshop served as the basis for this guidance. 
III.  Overview 
The information, characterization, and testing necessary for a device made through AM may 
depend on a variety of factors, including, but not limited to, whether it is an implant, an 
instrument, single-use versus reusable, load-bearing, and/or available in pre-specified 
standard sizes or is patient-matched.  This guidance outlines technical aspects of an AM 
device that should be considered through the phases of design development, production 
process, process validation, semi-finished and final finished device testing.  Not all 
considerations described will be applicable to every device, given the variety of AM 
technologies, materials, and devices made with additive manufacturing.  You should 
determine and justify which considerations are appropriate for your device based on the 
material and technology being used and the intended use of the device.  For example, a 
device made via powder bed fusion from titanium would not need to address liquid material 
or polymer considerations.   
Similarly, not all considerations are expected to be addressed in premarket submissions of 
AM devices.  It is anticipated that AM devices will generally follow the same regulatory 
requirements and submission expectations as the classification and/or regulation to which a 
non-AM device of the same type is subject.  In rare cases, AM may raise different questions 
of safety and/or effectiveness.  In addition, this guidance only addresses manufacturing 
considerations related to the AM process.  If it is unclear what technical information should 
be provided in a premarket submission for an AM device, we strongly encourage 
manufacturers to engage with CDRH or CBER through the Pre-Submission process to obtain 
more detailed feedback.  For more information on Pre-Submissions, please see Requests for 
Feedback on Medical Device Submissions: The Pre-Submission Program and Meetings with 
FDA Staff - Guidance for Industry and Food and Drug Administration Staff.4   
                                                           
 
4http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM31
1176.pdf  
  4 
  Contains Nonbinding Recommendations 
 
The overall AM process and the related sections in this guidance are shown in the flow chart 
below (Figure 1).  The first step is the design process, which can include a standard design 
with discrete pre-specified sizes and models, or a patient-matched device designed from a 
patients own medical images.  Once the device design is converted to a digital file, the 
software workflow phase begins, and that file is further processed to prepare it for printing. 
Printing parameters are optimized, and the build file is converted into a machine-ready 
format.  Concurrently with this step, material controls are established for materials used in 
the printing of the device.  After printing is complete, post-processing of the built device or 
component (e.g., cleaning, annealing, post-printing machining, sterilization, packing and 
labeling) takes place.  After post-processing, the final finished device is ready for testing and 
characterization.  Your quality system should be applied across all of these processes. 
 
  Material Control 
 
 
  Final Testing 
Design  Software Workflow  Build  Post Processing 
  Considerations 
 
 
Figure 1: Flow chart of the AM process 
IV.  Definitions 
The following definitions apply to this guidance and may not be applicable to any other 
documents issued by the FDA.   
AM Machine (machine)  a portion of the additive manufacturing pipeline including 
hardware, machine control software, required set-up software and peripheral accessories 
necessary to complete a build cycle for producing parts 5   
Build Cycle  single process cycle in which one or more components are built up in layers in 
the process chamber of the additive manufacturing system.6  
Build Preparation Software  the software used to convert the digital design to a format 
that can be used to build a device or component through an AM process.  This may include 
multiple software components. 
Design Manipulation Software  the computer program that allows a medical device design 
to be modified for specific circumstances (e.g., patient-matching). This may include multiple 
software components. 
                                                           
 
5ISO/ASTM 52900 Additive manufacturing  General principles  Terminology 
6ISO/ASTM 52900 Additive manufacturing  General principles  Terminology 
  5 
  Contains Nonbinding Recommendations 
 
Lot or Batch  one or more components or finished devices that consist of a single type, 
model, class, size, composition, or software version that are manufactured under essentially 
the same conditions and that are intended to have uniform characteristics and quality within 
specified limits.7 
Quality  the totality of features and characteristics that bear on the ability of a device to 
satisfy fitness for use, including safety and performance.8  
V.  Design and Manufacturing Process Considerations 
This section highlights technical considerations that should be addressed as part of fulfilling 
Quality System (QS) requirements for a regulated device made in whole or in part by AM.   
However, this guidance is not intended to comprehensively address all regulatory 
requirements for a quality system.  For class II and class III devices and select class I 
devices, manufacturers must establish and maintain procedures to control the design of the 
device in order to ensure that specified design requirements are met per 21 CFR 820.30 
Design Controls.  Manufacturers must also establish and maintain procedures for monitoring 
and control of process parameters for validated processes to ensure that the specified 
requirements continue to be met.9  Where the results of a process cannot be fully verified by 
subsequent inspection and test, the process must be validated with a high degree of assurance 
and approved according to established procedures.10  FDA interprets these regulations to 
require manufacturers to establish procedures including validation of the manufacturing 
process of AM devices to ensure that the device can perform as intended.  Please note that 
exemption from the requirement to submit a premarket notification (510(k)) does not mean a 
device is exempt from compliance with QS requirements.   
There are some devices that are specifically exempted by regulation from most QS 
requirements.  Manufacturers should refer to applicable regulations for their specific device 
type to determine what QS requirements apply.  In this section, the use of the terms 
document, describe, and identify refers to documentation requirements according to 
the QS regulation and premarket submission requirements for manufacturing information 
determined by the regulation for a specific device type or classification, regardless of the 
method of manufacture.  Not all considerations described will be applicable to an individual 
device, given the variety of AM technologies available.  Similarly, a premarket submission 
for a specific device may not need to address all considerations.  It is anticipated that AM 
devices will generally follow the same regulatory requirements as the classification and/or 
regulation to which a non-AM device of the same type is subject. 
                                                           
 
721 CFR 820.3(m) 
821 CFR 820.3(s) 
921 CFR 820.75(b) 
1021 CFR 820.75(a) 
  6 
  Contains Nonbinding Recommendations 
 
There are several AM technologies and different combinations of processing steps that can 
be used with each technology to build a device.  Therefore, it is important to clearly identify 
each step in the printing process.  A production flow diagram that identifies the steps 
involved in the manufacturing of the device, from the initial device design to the post-
processing of the final device, can help ensure the elements of product quality are addressed 
during production.  In addition, a high-level summary of each critical manufacturing process 
step may be helpful in documenting the AM process used.  The characterization of each 
process step should include, but need not be limited to, a description of the process, and 
identification of the process parameters and output specifications.  Since processes that 
optimize one design parameter may influence another, information on processing steps 
should demonstrate your understanding of these trade-offs and how they affect design 
outputs that are essential to the proper functioning of the device.  Additionally, the 
cumulative effects of prior processes on the final finished device or component should be 
incorporated into the development of each process step and documented.  The effects of the 
different steps in the AM processes can be seen in final device testing; however, determining 
the root cause of failures from manufacturing defects can be very difficult without a clear 
understanding of each step.  For example, in a powder bed fusion machine, the ratio of 
reused to virgin powder can affect melting properties, which affects the energy needed to 
create consistent bonding between layers, which in turn affects final mechanical properties.  
Similarly, risks identified for each step of the manufacturing process, as well as mitigations 
of these risks, should be documented.  Each AM process may have different critical steps and 
identified risks.  It is important to use all reasonably obtainable knowledge about your 
specific machines capabilities to ensure the manufacturing process outputs meet defined 
requirements.11  Quantitative knowledge of the machines capabilities and limitations can be 
gained through test builds, worst-case builds, or process validation (See Section V.F Process 
Validation and Acceptance Activities and Section VI.B Mechanical Testing for more 
information).   
As with traditional manufacturing methods, design requirements drive the processes that can 
be used to reliably produce the device.  It is therefore important to clearly identify key design 
parameters for your device, including, but not limited to, size range and available design or 
configuration options (e.g., range of angles between the trunnion and stem of the femoral 
component of a hip arthroplasty device).   
While this section includes manufacturing considerations, it is not intended to 
comprehensively address all considerations or regulatory requirements for establishing a 
quality system for the manufacturing of your device.  Aspects of the Global Harmonization 
Task Force Process Validation Guidance12 may be helpful in developing process validation 
procedures.  Additional information on design controls can be found in the Design Control 
                                                           
 
11ISO 14971 Medical devices - Applications of risk management to medical devices 
12 http://www.imdrf.org/docs/ghtf/final/sg3/technical-docs/ghtf-sg3-n99-10-2004-qms-process-guidance-
04010.pdf  
  7 
  Contains Nonbinding Recommendations 
Guidance for Medical Device Manufacturers.13  For general questions regarding the Quality 
System regulation, contact the Division of Industry and Consumer Education (DICE), Office 
of Communication and Education, at 1-800-638-2041 or 301-796-7100 or 
DICE@fda.hhs.gov. 
A.  Overall Device Design 
The innovative potential of AM may introduce variability into the manufacturing 
process that would not be present when using other manufacturing techniques.  
Specifically, we recommend that you compare the desired feature sizes of your final 
finished device to the minimum possible feature size of your AM technique and the 
manufacturing tolerances of the individual machine, given the build parameters and 
conditions under which the final device is expected to be made.  This is to ensure that 
devices and components of the desired dimensional specifications can be reliably 
built using the chosen additive technology.  Dimensional specifications for the final 
device or component, as well as manufacturing tolerances of the machine, should be 
documented.  Pixelation of features, where smooth surfaces become stepped, can lead 
to rougher surface finishes than expected. Surface finish requirements should be 
outlined in the product specification. 
B.  Patient-Matched Device Design 
Patient-matched devices (PMD) can be produced in many ways, some additive and 
some traditional.  AM is particularly suited to making PMD; consequently, this 
guidance attempts to address some of the considerations relevant to AM.  However, it 
does not provide an exhaustive list of considerations for a general patient-matching 
process.  All AM devices, including PMD, will share the considerations described in 
Section V.A.  Some PMD are based on a standard-sized template model that is 
matched to a patients anatomy.  With or without a standard-sized template, PMD 
may be produced within a defined design or performance envelope.  This 
performance envelope is determined before patient-matching can be initiated and 
describes the minimum and maximum dimensions, mechanical performance limits, 
and other clinically relevant factors.  Patient-matching can be accomplished by 
techniques such as scaling of the device using one or more anatomic references, or by 
using the full anatomic features from patient imaging.  Note that while patient-
matched or patient-specific devices are sometimes colloquially referred to as 
customized devices, they are not custom devices meeting the FD&C Act custom 
device exemption requirements unless they comply with all of the criteria of section 
520(b).  Most PMD will fall within the existing regulatory pathway for that particular 
13 http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm070627.htm 
8  Contains Nonbinding Recommendations 
device type.  For further information on custom device exemptions, please refer to 
the Custom Device Exemptions Guidance.14   
Patient-matched device designs may be modified either directly by clinical staff, the 
device manufacturer, or a third party in response to clinical inputs.  These inputs may 
be acquired from individual measurements, clinical assessments, patient imaging, or a 
combination thereof.  Alterations to the final device, and the methods used to make 
the alterations, may have direct consequences to the patient.  Therefore, you should 
clearly identify clinically relevant design parameters, the pre-determined range 
(min/max) for these parameters, and which of these parameters can be modified for 
patient-matching.  
Considerations for standard-sized devices should be applied to PMD as well.  In 
addition, for patient-matched AM devices, we recommend that you address the 
following, if applicable: 
(1)  Effects of imaging 
Many AM devices and components incorporate medical imaging data.  Every 
medical device will not need the same level of anatomic matching or imaging 
accuracy for optimal device performance.  Several factors may affect the fit of 
AM devices that use patient imaging to precisely control their size or shape, 
including, but not limited to: 
 the minimum image feature quality and resolution used for matching,
 any smoothing or image processing algorithms that may alter the
dimensions of the final device when compared to the reference anatomy,
 the rigidity of the anatomic structures being imaged, and
 the clarity of anatomic landmarks used to match the device to the patients
anatomy.
If the device relies on anatomic features that are not accurately imaged or are not 
consistent over time, then the final device may not fit the patient.  However, small 
changes in size or geometry may be difficult to identify during visual inspection 
of the device or through evaluation of patient imaging, and the mismatch may 
only be identified during device use.  Process validation (see Section V.FI.A(1)) 
is especially important to prevent these situations.  In addition, for devices 
intended to be fitted to or matched to soft tissues and non-rigid structures, it is 
important to note the range of changes that may be experienced by the soft tissue 
at the target location, such as deformation, when compared to the reference 
image. You should employ a risk-based approach, taking into consideration 
14http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM41
5799.pdf  
9  Contains Nonbinding Recommendations 
 
intended use of the device and design methodologies, to assess the scenarios that 
may yield a worst-case match. 
Many implantable devices and their patient-matched accessories depend on the 
patients anatomy to be clinically accurate representations of the recorded images 
in order for the device to function as intended.  Specifically, when the device is 
intended to match a patients anatomy, and that anatomy can change over time 
(e.g., with disease progression), the time that can elapse between when the patient 
is imaged and when the final device is used may need to be reflected in the 
expiration date of the device (see Section VII Labeling).  You should consider 
such potential time constraints associated with producing an AM device based on 
the intended use of your device. 
(2)  Interacting with design models 
Patient-matched devices are often made by altering the features of a standard-
sized device for each patient within a pre-determined range of device designs and 
size limits.  This is typically accomplished through the use of anatomical 
matching or design manipulation software that may be developed specifically for 
the AM device, or through other third party software.  Patient-matching may also 
be accomplished by manual methods using specific measurements on radiographs 
or key anatomic landmark measurements.  Any software or procedure used to 
make modifications to the device design based on clinical input should include 
internal checks that prevent the operator from exceeding the pre-established 
device specifications documented in the device master record.  We recommend 
that the design manipulation software or procedure used to make modifications to 
the device design identify the iteration of the design being changed by the 
operator.  You should also identify all medical devices and accessories that the 
design manipulation software is validated to work with.   
(3)  Complex design files 
Patient-matched devices that follow the patient anatomy precisely are especially 
vulnerable to errors in file conversion because anatomic curves are typically 
geometrically or mathematically complex, which can create difficulties when 
calculating conversions.  Additionally, for patient-matched devices, all of the file 
conversion steps are typically performed every time a device is built, whereas for 
a standard-sized device, most of the file conversion steps would be performed 
once during the design phase.  We recommend following the considerations in 
Section V.C.I.A(1) on maintaining data integrity throughout file conversions. 
(4)  Cybersecurity and Personally Identifiable Information 
Proper management and care of personally identifiable information (PII) and 
protected health information (PHI) is essential in any clinical application.  For 
more information on protecting PII and PHI, please refer to the HHS Guidance on 
  10 
  Contains Nonbinding Recommendations 
 
Significant Aspects of the Privacy Rule.15 We also recommend that device 
designers who include interactive steps in their patient matching workflow be 
familiar with implementing the FDA's Guidance on the Content of Premarket 
Submissions for Management of Cybersecurity in Medical Devices16 It is beyond 
the scope of this document to provide a full discussion of how these aspects are 
integrated into patient matching.   
C. Software Workflow 
The following sections highlight considerations that are especially important in the 
AM process. 
(1)  File Format Conversions  
AM typically involves interaction between several software packages, often from 
different manufacturers, which requires files to be compatible across the different 
software applications used.  Patient images, design manipulation software for 
patient-matching, digital point clouds and meshes, and machine-readable files 
each have their own standards, coordinate systems, and default parameters.  
Additionally, each software package has different ways of interpreting those file 
specifications.  Errors in file conversion can negatively impact final finished 
device and component properties, such as dimensions and geometry.  Therefore, 
we recommend that you verify the critical attributes and performance criteria of 
your final products as part of the software workflow validation to ensure expected 
performance, especially for patient-matched devices.  Factors that may cause 
unexpected conversion failures, such as changes to the software used, may trigger 
the need for revalidation (see Section V.F.I.A(2) Revalidation). 
When possible, final device files for printing should be maintained and archived 
or referenced in robust, standardized formats that are able to store AM-specific 
information so that the information can be retrieved when needed.  For instance, 
 
one option is the Additive Manufacturing File format (AMF) described in the 
ISO/ASTM 52915 Standard specification for additive manufacturing file format 
(AMF).  This, or a comparable file format or document control system, should 
include material information and the location of objects in a build volume and 
have high geometric fidelity (e.g., curved patches). 
                                                           
 
15https://www.hhs.gov/hipaa/for-professionals/privacy/guidance/significant-aspects/index.html 
16http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM35
6190.pdf 
  11 
  Contains Nonbinding Recommendations 
 
(2)  Digital Device Design to Physical Device  
When a digital device design is finalized, additional preparatory processes are 
needed before the device can be additively manufactured.  This is commonly 
accomplished using build preparation software.  These processes can be generally 
divided into four steps: 1) build volume placement, 2) addition of support 
material, 3) slicing, and 4) creating build paths. 
i.  Build Volume Placement 
Placement, orientation, and packing density of devices or components within 
the build volume may be integral to individual device or component quality.  
The distance between each device or component, and whether they are 
identical or different designs, can affect the material properties, surface finish, 
and ease of post-processing.  Build orientation of each device or component 
can also impact its functional performance by affecting the anisotropic 
properties of the device or component.  Similarly, many machines have areas 
of the build volume where they function optimally and areas where they do 
not.  For example, printing may be sub-optimal in the regions near the outer 
edge of the build volume and optimal at the center.  The affected region may 
be different for every machine, even between machines of the same model.   
Operation Qualification (OQ) of the printing process should include, but not 
be limited to, challenging the build volume placement to establish control 
limits which result in product that meets all predetermined requirements.  
These control limits may include acceptable placement regions, part 
proximity, and other parametric considerations.  Software tools are available 
to trace how devices are placed and oriented.  Process validation based on the 
risk profile of the device is preferable to a one-size-fits-all approach.  
ii.  Addition of Support Material 
Some types of AM require temporary support structures for certain design 
features during printing due to the layer-by-layer printing process.  The 
location, type, and number of supports can affect the geometric accuracy and 
mechanical properties of the final finished device or component.  Each AM 
technology has different needs for support material use to ensure the 
successful printing of a device.  For example, the critical overhang angle may 
be different for a stereolithography machine, an extrusion-based machine, and 
a metal powder bed fusion machine.  Automated algorithms are often used to 
choose the location and number of supports.  However, geometric 
complexities or printing limits often necessitate further manual intervention.  
Therefore, if your AM process requires support material, we recommend that 
you analyze the geometry and other requirements that could be affected by 
adding supports.  Some common structures that may need support are: 
  12 
  Contains Nonbinding Recommendations 
 overhangs,
 high aspect ratio features that protrude from the main body of the
device or component,
 internal features (e.g., voids, channels), and
 thin features prone to warping.
Support material can be removed physically or by chemical means.  Removal 
of support material may cause surface marks or leave residues on or in the 
device.  Manufacturing material removal processes (cleaning) should ensure 
that residues are removed to the level where they do not impact the safety or 
effectiveness of the product (see Section VI.E Removing Manufacturing 
Material Residues and Sterilization).  The complete description of the support 
material geometry and the removal process method should be included in the 
Device Master Record (DMR).  
iii. Slicing
Most AM techniques use a layer-by-layer printing process to fabricate 
components.  This necessitates slicing the models into layers.  Nominal layer 
thickness is determined by the machine specification and software 
capabilities, and an evaluation of the raw material.  However, technical 
characteristics of the machine and physical properties of the material may 
influence the achievable layer thickness.  The surface texture of a device or 
component, bonding between and curing of each layer, and sensitivity to 
power fluctuations can all be affected by the choice of layer thickness.  For 
example, the depth of material cured in a stereolithography system is 
primarily controlled by the energy density and additives in the liquid polymer.  
If the energy density is changed to reduce layer thickness and the additives are 
not adjusted properly, the layers may not cure or bond together completely.  
For systems where layers are created by melting the material, the layer 
thickness can similarly influence the energy needed to create a uniform melt 
pool to enable bonding to the layer below.   
Your choice of layer thickness should be documented, and reflect a balance 
between the above-mentioned effects, accuracy, quality, and printing speed. 
iv. Build Paths
The build path, the path traced by the energy or material delivery system (e.g., 
laser or extruder), can impact the quality of the final finished device or 
component.  For example, if the delivery system sweeps from left to right on 
the build volume, then makes the next pass from right to left, one side of the 
device or component has more time to cool or harden.  Similarly, the space 
between each line of the build path and the path speed will change the amount 
of melting and re-melting that the boundaries of each line of material will 
experience.  In addition, the build path may result in an orientation or 
13  Contains Nonbinding Recommendations 
 
anisotropy in the device or component.  We recommend that you assess 
whether differences in the build path significantly affect the performance of 
each component or device.  If so, it is important to maintain consistency of the 
build path between identical devices and components.  If more than one build 
path is used, each build path should be evaluated and documented. 
Some machines may allow portions of a device or component to have 
different energy delivery or build path specifications that do not change the 
geometry of the component or device but may influence the final device 
performance.  Other machines may allow the fill density of a component to be 
specified separately from patterns in the components geometry.  For example, 
if the geometry shows a solid wall, it is possible to fill that solid space with a 
sparse honeycomb instead.  These voids are easily formed with an extrusion-
based machine.  The fill density and fill pattern of parts that are not fully 
dense (i.e., not a solid) should be documented.  If a non-solid fill density is 
used, we recommend that you identify whether internal voids are externally 
accessible or if they are sealed.  If the voids are sealed but may be 
compromised during the course of the intended clinical use, you should 
identify the fluid or gas that fills the voids.  The risk associated with patient 
exposure to the materials in the voids should also be assessed. 
v.  Machine Parameters and Environmental Conditions 
Each AM technology and machine model has a unique set of parameters and 
settings that can be modified by the device manufacturer and those that are 
configured at the time of calibration (typically by the machine manufacturer).  
Maintaining proper calibration and performing preventative maintenance have 
been identified as key factors to achieve low rejection rates of devices and 
components from an individual machine.   
Environmental conditions within the build volume can also affect quality of 
the part.  For machines without a self-contained, well-controlled build 
volume, the ambient temperature, atmospheric composition and flow patterns 
can impact solidification/polymerization rate, layer bonding, and the final 
mechanical properties of the component.  Therefore, it is critical to establish 
and maintain procedures to adequately control environmental conditions 
within the build volume. 
Optimal settings and parameters for a single model of a machine can vary 
greatly when printing different devices or components.  Furthermore, optimal 
settings and parameters can vary between machines of the same model even 
when printing the same devices or components.  Some parameters that can be 
modified by the device manufacturer and may have a significant impact on the 
device or component quality include, but are not limited to: 
  14 
  Contains Nonbinding Recommendations 
 
  instantaneous power of the energy delivery system (e.g., temperature 
gradients of deposition nozzle for fused filament systems, energy 
density of laser or electron beam for powder bed fusion or 
stereolithography), 
  build speed or beam speed, 
  build path, 
  total energy density, and 
  focal point or nozzle diameter. 
Machine parameters should be documented, and the machine should be 
qualified for use in its installation location.  Aspects of the Global 
Harmonization Task Force Process Validation Guidance17 also address 
Installation Qualification. 
(3)  Validating and Automating Software Processes  
If you use a workflow that automates one or more software steps, you should refer 
to FDA Guidance on General Principles of Software Validation18. For more 
information on validating the manufacturing process, please refer to Section V.F 
Validation and Acceptance Activities. 
D. Material Controls 
(1)  Starting Material 
In the AM process, the starting material may undergo significant physical and/or 
chemical changes.  As such, the starting material can have a significant effect on 
the success of the build cycle, as well as on the properties of the final finished 
device.  Therefore, to ensure the consistency of the incoming raw material and the 
final product, the following information regarding each starting material used, as 
well as any processing aids, additives, and cross-linkers used, should be 
documented: 
  the identity of the material or chemical by common name, chemical name,  
trade names, Chemical Abstracts Service (CAS) number, or recognized 
consensus material standard, 
  material supplier, 
                                                           
 
17http://www.imdrf.org/docs/ghtf/final/sg3/technical-docs/ghtf-sg3-n99-10-2004-qms-process-guidance-
04010.pdf  
18http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm085281.htm  
  15 
  Contains Nonbinding Recommendations 
 incoming material specifications and material certificates of analysis
(COAs), with the test methods used for the COAs.  Applicable materials
standards and test methods (e.g. ISO or ASTM) should be referenced.
The specifications for incoming materials and test methods should be based on the 
AM technology used (e.g., material specifications will be different for powder 
based vs. stereolithography machines), the intended use of the final medical 
product, and the information available.  The specifications of the incoming 
materials (e.g., powders, liquid monomer/polymer systems) may be different from 
the properties of the finished devices. 
Examples of specifications for commonly used material types and machine 
technologies may include, but are not limited to: 
 if the material is a solid:  particle size and distribution and relevant
rheological performance for powders, or filament diameter and diametric
tolerances for filaments,
 if the material is a fluid: viscosity or viscoelasticity, and pot life,
 if the material is a polymer or monomer mixture: composition, purity,
water content, molecular formula, chemical structure, molecular weight, 
molecular weight distribution, glass transition temperatures, melting and 
crystallization point temperatures, purity information (e.g., purity of 
polymer/monomer and identification and quantity of relevant impurities, 
both inorganic and organic, as applicable),
 if the material is metal, metal alloy, or ceramic: chemical composition and
purity,

 if materials of animal origin are used, refer to:  Medical Devices
Containing Materials Derived from Animal Sources (Except for In Vitro
Diagnostic Devices,19 and
 if the material is a composite, the mix ratio with specifications provided
for each component.
In addition, when any material specification is changed, the effect on the build 
process and the final device should be well-understood and documented. 
(2)  Material Reuse 
Some AM approaches (e.g., powder bed fusion, stereolithography) allow efficient 
use of raw material by reusing the material that is not incorporated into the device 
19http://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm073
816.pdf  
16  Contains Nonbinding Recommendations 
 
(e.g., unsintered powder or uncured resin).  However, the reused material could be 
exposed to conditions (e.g., heat, oxygen, humidity, ultraviolet energy) that may 
alter it from the virgin state.  Therefore, we recommend that you describe the 
material reuse process, which may include, but not be limited to, a description of 
processes such as filtering reused material, a limit on the percent of reused 
material, or monitoring for changes in chemistry, oxygen, or water content.  We 
also recommend that you document evidence or provide a rationale that material 
reuse does not adversely affect the final device.  This may include an assessment 
of the reuse protocol by conducting studies on the effect of material reuse on the 
properties of the final finished device (see Section V.F.I.A(1) Validation).   
 
E. Post-Processing 
Final device performance and material properties can be affected by post-processing 
steps of AM (i.e., manufacturing steps occurring after the printing process).  These 
steps could include removing manufacturing residues from the device, heat treatments 
of the device to relieve residual stress, and final machining.  All post-processing steps 
should be documented and include a discussion of the effects of post-processing on 
the materials used and the final device.  As stated previously, manufacturers must 
establish and maintain procedures for monitoring and control of process parameters 
for validated processes to ensure that the specified requirements continue to be met.20  
The broad utility and ability to make multiple devices at once through AM means that 
some post-processing may be documented for a design, a device, or a build.  We 
recommend that you identify any potentially detrimental effects of post-processing 
and describe mitigations implemented.  For example, one common heat treatment 
method for metal devices is Hot Isostatic Pressing (HIP).  This process can reduce 
residual porosity and increase fatigue life but has also been shown to reduce the 
modulus and yield strength of the material.  Therefore, care should be taken to ensure 
both the AM and HIP processes maintain device performance.   
Devices that are intended for applications where fatigue is a factor may require 
minimum surface finish or roughness specification to reduce the chance of failure.  
The desired surface roughness can often be achieved through various post-processing 
steps (e.g., mechanical polishing); however, hard-to-reach spaces may remain in the 
as-built state.  These spaces should be assessed for their effects on mechanical 
performance (including fatigue) of the device or component.  See Section VI for 
Device Testing Considerations. 
 
F. Process Validation and Acceptance Activities 
                                                           
 
2021 CFR 820.75(b) 
  17 
  Contains Nonbinding Recommendations 
 
(1)  Process Validation 
Device quality, such as feature geometry, overall dimensions, material 
characteristics, and mechanical properties, are impacted by AM process 
parameters, process steps, and raw material properties, as described in the sections 
above.  In addition, for an identical device or component, quality may vary when 
built using different AM machines, even when the same machine model, 
parameters, process steps, and raw materials are used.  Therefore, knowledge of 
how the variability of each input parameter and processing step affects the final 
finished device or component is critical to ensuring part quality.  Where the 
results of a process cannot be fully verified by subsequent inspection and testing, 
the process must be validated with a high degree of assurance and approved 
according to established procedures.21 In addition all documentation must 
conform to the existing guidelines in the Quality System regulation for device 
validation.  Process validation must be performed to ensure and maintain quality 
for all devices and components built in a single build cycle, between build cycles, 
and between machines, where the results of a process (i.e., output specifications) 
cannot be fully verified by subsequent inspection and test.22  Software also must 
be validated for its intended use according to an established protocol23 (i.e., 
software workflow). 
For validated processes, the monitoring and control methods and data must be 
documented.24  This section provides some examples of methods for ensuring the 
consistency of quality. The list is meant to be representational of the type of 
factors to consider when performing process validation.  It can be used as a 
reference point but is not exhaustive.  The following examples may have the 
greatest applicability to powder bed fusion technologies, which comprise a large 
portion of AM medical devices.  Methods could include: 
  in-process monitoring of parameters such as: 
o  temperature at the beam focus, 
o  melt pool data, 
o  build-space environmental conditions (e.g., temperature, pressure, 
humidity), 
o  power of the energy delivery system (e.g., laser, electron beam, 
extruder), and 
o  status of mechanical elements of the printing system (e.g., recoater, 
gantry) 
In-process monitoring may also be helpful for processes that are not 
validated, but is not required. 
                                                           
 
2121 CFR 820.75(a) 
22See 21 CFR 820.75(a) 
23See21 CFR 820.70(i), and General Principles of Software Validation; Final Guidance for Industry and Staff. 
24See 21 CFR 820.75(b)(2) 
  18 
  Contains Nonbinding Recommendations 
 
  manual or automated visual inspection with defined acceptance criteria, 
  non-destructive evaluation (see Section V.E.3 Verification), and 
  test coupon evaluation (see Section V.E.4 Test Coupons). 
Not every AM system will be able to perform all these measurements, either 
because the process does not use them or because of technological limitations.  
Test methods used for process monitoring and control must be validated.25  For 
example, analysis should be conducted to confirm that test coupons used are 
representative of the final finished device or component and representative of a 
certain area within the build volume. 
A single failed component or device in a build cycle may not necessitate the 
rejection of all other devices or components within that build cycle.  The criteria 
for determining whether to reject a single device or component, or the entire 
build, should be established before testing.   
(2)  Revalidation 
Changes to the device, manufacturing process, or process deviations should be 
identified and analyzed for the potential risks they introduce.  Based on this 
assessment, the change or deviation may trigger the need for revalidation of the 
process.26  Manufacturers should rely on existing FDA Guidance for their 
regulatory pathway27,28,29,30 when considering a change to a previously cleared or 
approved device that uses AM.  Some examples of triggers for revalidation 
specific to AM are: 
  software changes (e.g., change or update of build preparation software), 
  changes in material (e.g., supplier, incoming material specification, reused 
powder, new formulation) or material handling, 
  change in the spacing or orientation of devices or components in the build 
volume, 
  changes to the software workflow (see Section V.B.2 Digital Device 
Design to Physical Device), 
  physically moving the machine to a new location, and 
                                                           
 
25 See 820.72(a) and 820.250(a) 
26See 820.70(b) and 820.75(c) 
27Deciding When to Submit a 510(k) for a Change to an Existing Device 
(www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm080235.htm) 
2830-Day Notices, 135-Day Premarket Approval (PMA) Supplements and 75-Day Humanitarian Device Exemption (HDE) 
Supplements for Manufacturing Method or Process Changes 
(www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM080194.pdf)  
29Modifications to Devices Subject to Premarket Approval (PMA) - The PMA Supplement Decision-Making Process 
https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm089360.pdf
30Changes or Modifications During the Conduct of a Clinical Investigation 
(www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm082158.pdf)  
  19 
  Contains Nonbinding Recommendations 
 changes to post-processing steps or parameters.
(3)  Acceptance Activities 
Acceptance activities are integral to process control.  Many AM technologies can 
produce more than one device or component simultaneously at different locations 
in the build volume.  Each of these devices or components can be copies of a 
single design or different designs.  This makes it more challenging to ensure 
repeatability and consistency within a build cycle and across lots.   
Some acceptance activities for individual devices or components can be 
performed through non-destructive evaluation (NDE).  Specifically, NDE 
techniques can be used for the verification of geometry, morphology, and some 
performance characteristics.  Techniques include, but are not limited to: 
 ultrasound,
 computed tomography (CT) or micro-CT,
 x-ray (in cases with simple geometry),
 dye penetration,
 confocal microscopy, and
 hyperspectral imaging.
Some techniques are not suitable for some materials, designs, or intended uses.  
General NDE testing protocols can be found from the ASTM and ISO 
Committees on Nondestructive Testing. Protocols specific to AM can be found 
from the ISO/ASTM Committee on Additive Manufacturing Technologies.31  If 
an NDE technique is used in your process validation or acceptance activities, the 
choice of technique used should be discussed and documented.   
(4)  Test Coupons 
A test coupon is a representative test sample of the device or component.  The 
design of test coupons and placement within the build volume can be especially 
important for AM.  Coupons can be simple shapes suitable for destructive 
mechanical testing, or they may contain one or more structural features (e.g., 
surface porosity, internal channels) representative of the component or device that 
can be assessed using destructive techniques.  We recommend that coupons be 
used to help with your process validation and to identify worst-case conditions in 
your manufacturing process (e.g., worst-case orientation and location in build 
volume).  Test coupons can also be used for in-process monitoring by placing 
them in build volume locations that are known to have the worst-case outputs.  
However, test coupons may not be needed if the process is validated per Quality 
31http://www.astm.org/COMMIT/SUBCOMMIT/F42.htm 
20  Contains Nonbinding Recommendations 
 
System requirements and coupon testing is not a process monitoring activity 
defined in your quality system.  These test coupons can confirm that the build 
cycle has met its performance specification for that portion of the build volume if 
the test coupons meet the performance specifications.  For example, test coupons 
may be placed at the edges of the build volume if edges are known to have less 
optimal build quality.  They may also be placed randomly in between components 
or devices to produce a sampling of the build quality.  Data to demonstrate that 
test coupons are representative of the components, in-process devices, or finished 
devices should be documented. Many factors can alter how well a test coupon 
represents any given part in the build space.  When coupons are used, they should 
be validated to accurately and reproducibly represent the one or more printed 
parts within a specific build volume. 
G. Quality Data 
The analysis of sources of quality data to identify existing and potential causes of 
nonconforming product, or other quality problems is an essential part of any quality 
system.  For devices produced by AM, it is important to consider whether it is 
necessary to keep track of the location in the build volume where a device or 
component was built.  This will depend on information obtained during process 
validation activities and design specifications.  For example, if process validation 
demonstrated that quality is not affected by location in the build volume, it may not 
be necessary to be able to keep track of the build volume location for each device.  
This level of specificity is important in identifying possible causes of failure when 
multiple different components or devices are made in the same build volume at the 
same time.  Therefore, you should ensure that quality data such as build volume 
location can be analyzed to enable proper identification of quality problems and 
investigation of the cause of nonconformities. 
 
VI.  Device Testing Considerations 
The following section contains a description of the type of information that we recommend 
that you include in a premarket submission of a device made using AM.  The type and 
amount of data to support a substantial equivalence determination or approval will vary 
depending on the intended use, risk profile, and classification and/or regulation for the device 
type.  In addition, the type of information needed for a device made through AM may also 
depend on a variety of factors, including but not limited to, whether it is an implant, load 
bearing, and/or available in pre-specified standard sizes or is patient-matched.  Not all 
considerations described will be applicable to a single device, given the variety of devices 
that can be made by AM and AM technologies available.  In general, if the type of 
characterization or performance testing outlined in each of the sub-sections below is needed 
for a device made using non-AM techniques, the information should also be provided for an 
AM device of the same device type.  If you have specific questions regarding the information 
to support a premarket submission for an AM device, please contact the relevant review 
  21 
  Contains Nonbinding Recommendations 
 
division in CDRH or contact CBER for products containing biologics, cells or tissues.  
Specific questions regarding jurisdiction over a combination product should be directed to 
the Office of Combination Products (OCP) at 301-427-1934 or combination@fda.gov. 
 
A. Device Description 
AM facilitates the creation of intermediate and customized device sizes.  Patient-
matched devices are a good example of this application.  Since these devices may not 
have discrete sizes, such as small, medium, and large, we recommend that you 
identify the range of dimensions for your device.  In addition, you should describe 
any design variations, for example, amount of anatomical coverage for a cranioplasty 
plate.  Any critical dimensions or features that are intended to be altered to match a 
patient should also be clearly identified, and the range of allowable values for these 
parameters should also be identified.  Since each type of AM technology has different 
technical considerations, you should describe the type of AM technology used to 
build your device.  In addition, because AM use for medical devices is relatively new, 
we recommend that you include a flow chart describing your AM process, including 
post-processing, in order to help determine if additional assessments are needed.   
Due to the generally complex geometry of AM devices, we recommend that critical 
features of the device be clearly described in the device description and identified in 
technical drawings.  For example, the location and thickness of porous scaffolding 
should be described, as these features may have reduced mechanical properties in 
comparison to a solid material.  In the technical drawings of your device we 
recommend that you identify components made using AM.     
B. Mechanical Testing 
The type of performance testing that should be conducted on a device made using 
AM is generally the same as if the device was manufactured using a traditional 
manufacturing method.  Depending on the device type, these may include material 
property testing such as modulus, yield strength, ultimate strength, 
creep/viscoelasticity, fatigue, or abrasive wear.  Performance testing should be 
conducted on final finished devices subjected to all post-processing, cleaning, and 
sterilization steps.  As with any recommended testing, the final finished device should 
be used or a rationale should be provided explaining why the test coupon used was 
representative of the final finished device.  In addition, the worst-case combinations 
of dimensions and features (e.g., holes, supports, porous regions) should be 
considered when determining the worst-case devices for performance testing.  You 
should also provide a discussion of how the worst-case devices were selected for each 
performance test conducted. 
Due to the nature of AM, devices will likely have an orientation (i.e., anisotropy) 
relative to the build direction and location within the build space.  The orientation and 
build location can affect the final properties and should be considered when 
  22 
  Contains Nonbinding Recommendations 
 
conducting device mechanical testing.  Specifically, the build orientation (including 
worst-case orientation) of devices or components should be identified for each 
performance test.  If the orientation changes with device size or design, the worst-
case orientation should be identified for each configuration.  Since the effect of 
orientation can vary based on the manufacturing technology used, a baseline study of 
the machine/material combination used may be helpful in determining the degree to 
which the build orientation will affect mechanical properties.  Coupons may be used 
for material property assessments if there is adequate justification provided for why 
the coupon is representative of the final device.  This justification should consider 
critical design elements, post-printing processes, cleaning, disinfection and/or 
sterilization as they relate to each type of testing.  This information can be used to aid 
in the selection of worst-case samples with respect to orientation.   
In addition, for some AM machines, the location within the build space can have an 
effect on mechanical properties.32  For example, for powder bed systems, the 
difference in distance from the energy source to different locations in the build space 
(e.g., center vs. corner) could lead to variability in the mechanical properties of 
devices built in those locations.  To determine whether build location has a significant 
effect on device characteristics or performance (including fatigue strength), we 
recommend that you perform a baseline study of your machine/material combination 
(see Section V.E.1 Validation).  The use of coupons for your baseline study is 
recommended.  If there is a significant effect, build location should be considered in 
the identification of worst-case samples for mechanical testing.   
Since mechanical properties of the device may be impacted by orientation and 
location, it is important to ensure that production processes are properly developed, 
conducted, controlled, and monitored in order to ensure that devices or components 
are not adversely affected by fabrication orientation.  The process validation 
described in Section V.F.  Process Validation and Acceptance Activities may be used 
to address the impact of orientation and location. 
 
C. Dimensional Measurements 
Similar to mechanical properties, device dimensions may be affected by orientation 
and location within the build space.  Therefore, we recommend that you specify the 
dimensional tolerances and perform dimensional measurements for the worst case 
additively manufactured devices and/or components.  Samples selected for the 
assessment of dimensional measurements should address variability due to orientation 
and build location if baseline studies show a dependence on these parameters.  To 
demonstrate consistency and reproducibility between build cycles, dimensional 
                                                           
 
32ASTM F3122 Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive 
Manufacturing Processes 
  23 
  Contains Nonbinding Recommendations 
 
measurements should be made on samples from multiple build cycles, and a 
justification should be provided on the sampling scheme used.  Alternatively, you 
may use process validation information to demonstrate that there is negligible 
variability between build cycles. 
While we are aware of the potential effects of orientation and build location on 
mechanical properties and dimensional tolerances, there may be other properties that 
could be affected based on the intended use and technological characteristics of the 
device. 
D. Material Characterization 
(1)  Material Chemistry 
Since the AM process creates the final material or alters the starting material 
during the process, all materials involved in the manufacturing of the device 
should be identified.  As noted in Section V.C Material Controls, this information 
should include the source and purity of each material used.  Certificates of 
Analysis and/or Materials Safety Data Sheets (MSDS) can facilitate the review of 
each material.  The Chemical Abstract Service (CAS) number, if available, of 
each chemical component should be provided.  If material chemistry information 
in a device master file (MAF) will be referenced, you should include a right to 
reference letter from the MAF holder in your premarket submission.33  You 
should also document the material composition of the final finished device. 
Given the iterative nature of AM, the starting material can be exposed to partial 
re-melting and solidification processes multiple times, which may result in 
unexpected or undesired material chemistries for some polymer systems.  
Therefore, if biocompatibility is not evaluated as described in the guidance Use 
of International Standard ISO-10993, "Biological Evaluation of Medical Devices 
Part 1: Evaluation and Testing within a Risk Management Process34 or if 
biocompatibility testing identifies a concern, additional material chemistry 
information may be needed.  For example, a description of all material chemistry 
changes expected during the manufacturing of your device may be needed.  In 
addition, based on this description and the material/machine type used, it may also 
be necessary to provide additional information or testing for polymers to ensure 
that there are no unintentionally formed chemical entities that could pose a risk to 
patient health.   
                                                           
 
33http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/HowtoMarketYourDevice/PremarketSub
missions/PremarketApprovalPMA/ucm142714.htm  
34https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM3
48890.pdf  
  24 
  Contains Nonbinding Recommendations 
 
(2)  Material Physical Properties 
Inter-layer bonding (adhesion/cohesion) is unique to AM and determines the 
ultimate structural integrity of the final finished device.  As such, material 
properties known to affect interlayer bonding should be characterized.  This 
information should be representative of the final finished device (subjected to all 
post-processing, cleaning, and sterilization steps).  Material properties can be 
determined from the final device or using coupons.  If coupons are used, a 
description of the coupon and a justification for why coupon testing is 
representative of the final device should be provided.   
If your device is additively manufactured using metal or ceramic, we recommend 
that you characterize the microstructure, which may include but is not limited to 
grain size, orientation, and phase composition.  Existing consensus standards for 
materials can be used for comparison.  If the AM process results in structural 
inhomogeneity, microstructural voids, incomplete consolidation, or other 
microstructural issues, additional mechanical testing may be needed to show that 
these issues do not affect device performance. 
If your device is additively manufactured using polymers, we recommend that 
you ensure the AM process is consistently creating a device or component that 
has properties that meet your specifications.  For example, in situ crosslinked 
devices may have crosslink density gradients across the build.  For AM processes 
that use polymer crosslinking, the percent crosslinking and degree of curing 
should be evaluated to ensure that the AM process results in a material that is 
fully cured and within specifications.  For systems using a crystalline or semi 
crystalline material, crystallinity and crystalline morphology should be 
characterized to ensure that the AM process is not adversely altering the polymer 
structure and subsequently altering the performance (e.g., creep, material 
transparency) of the final device.  For hydrogel materials, the percent water 
swelling or water content of the material should be reported to ensure that that the 
AM process has not adversely affected the materials ability to uptake water.   
If your device is additively manufactured using an absorbable material, we 
recommend that you perform in vitro degradation testing using final finished 
devices or coupons.  If coupons are used, they should be representative of your 
final finished device in terms of both processing and properties (e.g., surface-to-
volume ratio, crystallinity).  This will establish whether AM has an adverse effect 
on the degradation profile of the material. 
E. Removing Manufacturing Material Residues and 
 
Sterilization 
AM facilitates the creation of devices with complex geometries, such as engineered 
porosity, honeycomb structures, channels, and internal voids or cavities that cannot be 
produced by traditional manufacturing methods.  Such complex geometries in 
  25 
  Contains Nonbinding Recommendations 
 
additively manufactured devices are expected to increase the difficulty in removing 
manufacturing material residues (cleaning) and in sterilization due to the likelihood of 
increased surface area, generation of extensive tortuous pathways, and creation of 
internal voids with limited or no access.  Additionally, AM allows porous structures 
to be produced earlier in the manufacturing process than many traditional methods, 
which could result in greater soiling by the manufacturing material of those porous 
structures throughout the rest of the process.  Therefore, validation of the reduction of 
the manufacturing material residue to levels that do not adversely affect the devices 
quality and sterilization process validation should account for the complex geometry 
of your device under worst-case conditions (e.g., greatest amount of residual 
manufacturing materials, and a combination of largest surface area, greatest porosity, 
and most internal voids for sterilization validation). 
Manufacturing material means any material or substance used in or used to facilitate 
the manufacturing process, a concomitant constituent, or a byproduct constituent 
produced during the manufacturing process, which is present in or on the final 
finished device as a residue or impurity not by design or intent of the manufacturer.35   
There is also an increased risk of residual manufacturing material, such as excess 
starting material or support material, remaining on the final finished device.  Since 
residual manufacturing material may negatively affect the performance of the device, 
you should describe the process used to ensure removal of residual manufacturing 
materials to a level where they do not affect the safety and effectiveness of the device.  
Note that for complex geometries and trapped volumes, destructive testing may be 
needed to properly validate the removal of the manufacturing material. 
  
When a manufacturing material could reasonably be expected to have an adverse 
effect on device quality, the manufacturer must establish and maintain procedures for 
the use and removal of such residual manufacturing material to ensure that it is 
removed or limited to an amount that does not adversely affect the device's quality. 36 
It is important to note that many end user facilities may not have routine access to the 
equipment or materials needed to implement cleaning procedures that are designed to 
remove residual manufacturing materials and that personnel are likely not adequately 
trained to perform such cleaning procedures.  Therefore, only devices that are 
sufficiently cleaned of residual manufacturing materials should be provided to the end 
user.  While engineered porosity and complex geometries are generally an advantage 
of additive manufacturing, highly porous regions are expected to be difficult to clean 
in comparison to devices made with other manufacturing methods, and can also 
greatly increase the surface area of the device.  Therefore, we also recommend that you 
include an overview or summary of manufacturing residue removal process and 
information (e.g., testing procedure and data) in your premarket submission to 
                                                           
 
35 See 21 CFR 820.3(p) 
36 See 21 CFR820.70(h) 
  26 
  Contains Nonbinding Recommendations 
 
demonstrate that your device is cleaned of manufacturing residues before being provided 
to the end user. 
The extent to which manufacturing material residue must be reduced is determined on 
case-by-case basis considering characteristics such as: manufacturing processes, 
intended use, materials, type and duration of exposure, intended anatomical location, 
and type of device.  In addition, we recommend using final finished devices after they 
have undergone all other processing for assessment of manufacturing material 
removal and validation of the sterilization process.  For additional information on 
sterilization and validation, see Submission and Review of Sterility Information in 
Premarket Notification (510(k)) Submissions for Devices Labeled as Sterile.37 
If additively manufacturing a reusable medical device that involves reprocessing or a 
device intended for end-user sterilization in health care facilities, we recommend the 
inclusion of reprocessing instructions in your device labeling.  Please refer to the 
guidance, Reprocessing Medical Devices in Health Care Settings: Validation 
Methods and.38 
F. Biocompatibility 
We recommend that you evaluate the biocompatibility of the final finished device as 
described in the guidance Use of International Standard ISO-10993, "Biological 
Evaluation of Medical Devices Part 1: Evaluation and Testing within a Risk 
Management Process.39  If chemical additives with known toxicities are used (e.g., 
certain additives, catalysts, binding and curing agents, uncured monomers, 
plasticizers), additional information, as outlined in the guidance,40 may be necessary.   
VII.  Labeling 
Device labeling should be developed in accordance with applicable regulations, 
device-specific guidance documents, and consensus standards. 
Labeling Considerations for PMD 
                                                           
 
37https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm10
9897.pdf   
38http://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm253010.
pdf  
39https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm34
8890.pdf   
40https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm34889
0.pdf  
  27 
  Contains Nonbinding Recommendations 
 
Since clinical staff, device manufacturers, or a designated third party might modify 
the design of a PMD, additional labeling information is recommended for AM 
devices that are patient-matched.  We recommend that each AM PMD be marked or 
have accompanying healthcare practitioner labeling included in the packaging to 
identify: 
  patient identifier, 
  use (e.g., left distal femoral surgical guide), and 
  final design iteration or version used to produce the device. 
The expiration date for a patient-matched device may be driven by the patient 
imaging date or the design finalization date rather than the standard methods of 
determining device shelf life (see Section V.B.(1)).   In addition, it is possible that the 
patient may have experienced events between the time of imaging and surgery (e.g. 
additional trauma), which could impact performance of the device.  Therefore, we 
recommend that you include a precaution in your labeling that the patient should be 
surveyed for potential anatomical changes prior to the procedure.   
  28