ationale:  Verification of the digital part definition ensures that subsequent and derivative digital 
products are produced to the correct and uncorrupted files. Model validation’s role in digitally 
identifying discrepancies can be crucial for ensuring the integrity of downstream AM products.] 

Conformance to this requirement can be demonstrated by using a methodology that includes 
considerations for digitally sensitive processes (e.g., meshing process and subsequent analysis for 
the quality of meshed models). Software characterizing and controlling embedded information 
within the digital part definition can be crucial to supporting an assessment regarding digital 
quality. Common practices to maintain part model integrity ensure that data formats, coordinate 
systems, and digital tolerances are identified and conserved through the digital thread. Although 
software validating portions of the digital thread exist (e.g., those providing CAD validation), 
demonstrating part model integrity requires the combination of numerous digital considerations 
identifying and controlling the AM process. These practices are supported through standards (e.g., 
ASME Y14.41, Digital Product Definition Data Practices: Engineering Product Definition and 
Related Documentation Practices, and ASME V&V 40, Assessing Credibility of Computational 
Modeling through Verification and Validation: Application to Medical Devices). It should be noted 
that standards for quality assurance of digital aspects of the AM process are still being actively 
developed; consequently, the number of relevant standards demonstrating digital product control 
will increase with the maturity and adoption of AM.  

 On-Machine Execution 

[AMR-29]  Any unplanned modifications to the build file on the machine during AM process setup 
and/or execution shall be assigned a nonconformance and traceable via a records management 
system controlled by the QMS. 

[Rationale:  Modifications to the build file during process execution is a deviation from the QPP.]  

Some AM software requires the location of the digital model to be placed or located in the build 
volume on the machine. Location in the build volume is considered part of the QPP; therefore, a 
placement in the build volume that differs from this location is considered a nonconformance. At the 
point of build file execution, digital alterations to the build file are treated as a nonconformance. 


4.14 Production Engineering Record 

[AMR-30]  For Class A and B parts, the AM part production process shall be controlled by a 
revision-controlled production engineering record, consistent with the QPP, that contains, at a 
minimum and when applicable, records of production for the following: 

The production engineering record is commonly called a shop traveler, manufacturing router, 
production planning, or engineering master. The production engineering record derives from and is 
traceable to the QPP and is consistent with the QMS; see section 8 of this NASA Technical 
Standard. The production engineering record not only describes the sequence of actions and 
verifications applicable to the process but can also be a mechanism, particularly when managed 
digitally, for acquiring process step completion data and in-process verification results, installing 
hold-points for mandatory inspection points, and documenting process metadata (e.g., dates, 
operators, digital threat revisions, procedure revisions, etc.).  

Note that the production engineering record may reference other revision-controlled processes and 
procedures. 

a. Feedstock removal for any part with geometry precluding line-of-sight confirmation. 

Feedstock remaining in the part presents hazards to proper part and system operations. For 
example, removing residual material following a hot isostatic pressing (HIP) process for metallics 
or an ultraviolet (UV)-curing process for polymerics may not be feasible. Therefore, it is important 
that all passages are verified to be clear of material prior to this step. Proper cleanliness may be 
impossible to achieve later in post-processing, particularly for debris-sensitive hardware. Powder 
removal on surfaces that do have line of sight are assumed to be addressed by 
contamination/cleanliness requirements. 

b. As-built part visual inspections for any indications of build anomalies prior to processes 
that may alter the as-built state of the part. 

All anomalies should be recorded in detail and be traceable via a records management system 
controlled by the QMS. Many indicators of AM process quality are best evaluated prior to further 
part processing, including many indicators (e.g., coloration or support damage) that may be 
eliminated during further part processing. Build anomalies include, but are not limited to, witness 
lines on the part surface (if applicable to the AM technology), unusual discoloration, laminar 
defects (e.g., cracks or tears), separation of part from support structures, and geometric distortion. 
High-quality photographs to document the as-built part inspection process are recommended, 
particularly for unusual observations or anomalies. 

c. Platform removal. 

The sequence and process of platform removal should be controlled to prevent part damage and to 
ensure interfacing part surfaces retain their intended quality and part traceability is maintained. 


d. Support structure removal. 

The process for support structure removal should be controlled to prevent part damage, to ensure 
interfacing part surfaces retain their intended quality, and to maintain part and specimen location 
and orientation when required. 

e. Machining. 

Machining operations should be properly staged relative to joining operations, inspections, and 
thermal processing to ensure part integrity is maintained and verifiable. 

f. Thermal processing:  environmental conditions (times, temperatures, atmosphere/media), 
process specifications, quenching media, surface condition of the part, etc. 

Part performance is assumed to follow properties developed with microstructures evolved through 
thermal processes defined in the QMP. Without proper thermal processing controls, part materials 
may not perform as intended. Industry standards for heat treatment that are not AM specific can be 
used and referenced to fulfill this requirement. 

g. Light-activated curing:  environmental conditions (times, ambient light, temperature, 
atmosphere/media), process specifications, part orientations, wavelength, intensity, duration, etc. 

Part performance for processes (e.g., vat photopolymerization) is assumed to follow properties 
developed with increased polymerization, evolved through light-activated curing defined in the 
QMP. Without proper processing controls, part materials may not perform as intended. 

h. Joining operations (e.g., welding, brazing, soldering, adhesive bonding) that were 
developed and qualified to an appropriate aerospace standard using representative AM material. 

Joining operations on AM parts are not exempted from standard joining process controls as 
implemented through NASA-STD-6016, Standard Materials and Processes Requirements for 
Spacecraft, and NASA-STD-5006, General Welding Requirements for Aerospace Materials. Unique 
preparation and sequencing may be involved in the joining of AM parts. 

An example includes the sequencing of welding operations by the production engineering record to 
accommodate machining to remove remnants of as-built AM surface from weld lands and to stage 
heat treatment operations to optimize weld performance and minimize weld residual stress. 

This NASA Technical Standard does not levy specific inspection requirements for welds on AM 
hardware. Inspections are dictated by standard practice based on the class of weld or the fracture 
control classification of the weld. 


Welding standards will typically be levied by the program or project through materials and 
processes requirements (NASA-STD-6016 and NASA-STD-5006) and tailored by the CEO. 

If adhesive bonding processes are applied to AM parts, all surface treatment processes should also 
be characterized and controlled. 

i. Surface treatments that are influential to the performance of the part, structural or 
otherwise. 

Surface treatment operations can have significant impact on part performance and may underlie 
assumptions of material capability such as fatigue performance. Improperly controlled surface 
treatments can adversely affect part quality and safety. 

j. Part marking:  part identifiers and serial numbers, including the locations and method for 
all marking. 

Uncontrolled marking procedures present unwarranted risk to the part. Incorporation of a static 
part identifier directly in the build geometry is acceptable as long as it is protected during post-
build operations, does not interfere with part acceptance inspections, and does not impact the 
performance of the part (e.g., laser marking or vibro peening, which impacts fatigue resistance). 
The use of the AM build process to implement serialization is not compatible with a fixed QPP and 
should not be used. 

k. Cleaning and part cleanliness. 

Failure to properly control cleaning procedures can lead to contamination-related failures within 
the part or system. Cleanliness levels and methods of verification are governed by the 
contamination control plan for the hardware and comply with appropriate standards, such as IEST-
STD-CC1246, Product Cleanliness Levels - Application, Requirements, and Determination, or 
MSFC-SPEC-164, Cleanliness of Components for Use in Oxygen, Oxidizer, Fuel, and Pneumatic 
Systems, Specification for. 

l. Inspections, including, but not limited to, dimensional inspections, surface texture 
measurements, and NDE. 

See section 4.8 of this NASA Technical Standard for additional information regarding NDE. 

Confirmation of physical measurements and inspections is important for part conformance but is 
also an aspect of AM process control. Dimensional errors and flaws for the AM process can be an 
indication of process escape. Internal measurements may be confirmed using computed 
tomography, provided that a part analog reference is used to confirm accuracy and precision of the 
measurements as well as calibration of the tool and data post-processing methods. 

m. Part handling, packaging, and shipping. 


Part integrity can only be maintained when proper handling and packaging controls are in place to 
preclude damage. An example of packaging controls may be found in NPR 6000.1, Requirements for 
Packaging, Handling, and Transportation for Aeronautical and Space Systems, Equipment, and 
Associated Components. 

[Rationale:  The production engineering record creates traceability between the qualified AM 
process conditions and controls, the execution of that process, and final product conformance. The 
complex nature of AM parts creates a product assurance dependency on the acquisition of objective 
evidence of process conformance. Minimum criteria for build-specific data acquisition are built into 
the production engineering record for this purpose.] 

For proper AM part traceability, it is important that the production engineering record 
unambiguously define which records are required to establish the complete production data 
package for the part. 

Applicable processes contained in the production engineering record should be all processing 
described by the QPP; see section 8 of this NASA Technical Standard. 

As a quality record, the production engineering record may also be used as the documentation 
source of process control requirements and, depending on its implementation, a record of 
verifications made during the process. The production engineering record may reference other 
checklists or operating instructions that are controlled by the QMS. 

In accordance with contract and QMS requirements, all part records are archived for the 
prescribed period and remain fully traceable, including those provided by external suppliers for 
operations such as heat treating, machining, or inspection. All witness specimen test results and 
records, as well as nonconformance documentation, are included in the certification of compliance 
records for the part. When complete, it is recommended that a final, summarized certification-of-
conformance record be generated to demonstrate that all requirements have been met, all 
nonconformances have been resolved, and the part is fit for service. 


4.15 Preproduction Articles 

[AMR-31]  For Class A and B parts, a preproduction article evaluation verifying quality of part and 
material shall be conducted for all AM parts, with the plan for evaluation being approved as part of 
the PPP. 

[Rationale:  A preproduction article evaluation is necessary to confirm that the design intent of the 
part is fully realized by the defined part process. Many aspects of part quality vary with part 
process and can only be verified through the preproduction article assessment (e.g., material 
internal quality and mechanical performance).] 

To meet the intent of this requirement, a preproduction article evaluation has to be based on the 
finalized build configuration. This configuration includes all parts, supports, and witness specimens, 
and uses all processes impacting the material condition of the part, beginning with the AM build 
process through part marking and final acceptance. 

The preproduction article evaluation plan, given in the PPP or referenced therein as a separate 
plan, includes a complete description of each stage of the evaluation, with emphasis on evaluations 
needed as the part proceeds through processing. Some preproduction article evaluations may 
require more than one part to adequately capture all objectives. The preproduction article 
evaluation plan, process, and report should follow the intent of SAE AS9102, Aerospace First 
Article Inspection Requirement, except that as a preproduction article (as opposed to “first 
article”), the evaluations extend beyond the production engineering requirements to matters of 
material internal quality and mechanical performance. The preproduction article evaluation plan is 
approved as part of the PPP. 

At a minimum, the preproduction article evaluation plan should address the following topics, 
although relevance and importance are expected to vary by part: 

 Material removal and confirmation techniques. 
 Platform removal procedures. 
 Thermal processing procedures (where applicable). 
 Light-activated curing procedures (where applicable). 
 Dimensional inspections, accessible and post-sectioning. 
 Surface improvement procedures, sufficiency, and coverage. 
 Surface texture measurements, accessible and post-sectioning. 
 Part sectioning cut plans. 
 Testing within part:  microstructure, chemistry, mechanical. 
 AM risk area evaluations:  sectioning and tests target any high AM risk areas of the part. 
 Witness specimen evaluation:  all defined witness specimens for the build are tested and 
reported. 
 Part cleaning requirements. 


4.16 Proof Testing 

[AMR-32]  All Class A and B AM parts shall be proof tested as part of acceptance testing unless 
otherwise substantiated as part of the Integrated Structural Integrity Rationale in an approved PPP. 

[Rationale:  Proof testing can provide direct confirmation of structural integrity and may be a 
significant contributor to the structural integrity rationale. Structural failure risks due to defects, 
uncontrolled processes, or errant workmanship are mitigated though the proof test acceptance test.] 

This requirement provides for a proof acceptance test on each part as a fundamental aspect of part 
quality assurance to protect against manufacturing process escapes that may impact structural 
integrity. For Class A parts, the proof test is typically one aspect of a larger rationale for part 
integrity. For Class B parts, in particular those that are fail-safe by redundancy, the proof test helps 
defend against “common cause” failures due to manufacturing process escapes that may affect 
multiple parts yet go undetected due to relaxed inspection requirements in this part class. 

Although a proof test may potentially be used to quantitatively screen parts for defects as an aspect 
of fracture control in Class A parts, this requirement levies only a "workmanship" proof, which does 
not necessitate a quantitative assessment of defect screening. Proof tests levied by other structural 
requirements automatically satisfy this requirement. If the proof test is not meaningful, beneficial, 
or practical, then the rationale for not performing the proof test, including planned actions that 
mitigate the risk of not proof testing, may be described and approved as part of the Integrated 
Structural Integrity Rationale within the PPP (see section 7.3 of this NASA Technical Standard). In 
cases where the proof test is performed solely due to this quality assurance requirement, proof test 
factors and other precautions should follow the trends for similar hardware scenarios provided by 
structural requirements. In the absence of other suitable guidance, a proof factor of 1.2 on limit 
conditions with proper environmental corrections for strength are considered appropriate for part 
acceptance. 

It is highly recommended that all AM parts, including Class C parts, be proof tested as effectively as 
their design will accommodate. For fracture critical/damage tolerant parts, the integrity proof test 
assessment may also require an evaluation of the flaw size screened in proof and the estimated life 
assured by proof testing. Proof test cyclic life evaluations may occur analytically or experimentally. 

The requirement for proof testing is governed by the program or project structural design and 
verification requirements. The approval of the proof test and the specifics of the test itself are 
reviewed and approved by the delegated Technical Authority. 


4.17 Qualification Testing 

[AMR-33]  All AM parts in Classes A1 through B2 shall be subject to a qualification test program 
that demonstrates that part performance and functionality meet the mission design requirements, life 
factors, and life-cycle capability, given the following stipulations: 

a. Parts for qualification testing are produced to a QPP. 

b. Any AM part that functions as part of a mechanism is subject to the qualification, design 
life verification, and acceptance testing defined by NASA-STD-5017, Design and Development 
Requirements for Mechanisms. 

c. The protoflight approach to qualification of hardware as defined in NASA-STD-5001 or 
JSC 65828, Structural Design Requirements and Factors of Safety for Spaceflight Hardware, which 
does not include a dedicated test article, is not considered applicable to AM hardware of Classes A1 
through B2, nor is the “no test” option for verification by analysis only. 

[Rationale:  Given the current maturity of the AM design process and the potential for 
unanticipated failure modes, the need for experimental evidence confirming the design performance 
of AM parts through a performance qualification test series exists.] 

Parts may be qualified individually (if applicable) as part of a subsystem qualification or as part of 
an overall system qualification. Qualification tests are recommended for AM parts of all classes. If 
direct qualification testing is not feasible for a part in Classes A1 through B2, then an alternative 
rationale for part qualification may be proposed in the PPP.  

The requirement for qualification testing is governed by the program or project structural design 
and verification requirements. The approval of the qualification test and the specifics of the test 
itself are reviewed and approved by the delegated Technical Authority. 

4.18 Part Acceptance 

 Part Acceptance, Class A and B Parts 

[AMR-34]  For Class A and B parts, data that are objective evidence of part conformance shall be a 
prerequisite for acceptance of the part by the CEO and made available to NASA upon request, 
including, but not limited to, information showing compliance to all part acceptance items listed in 
an approved PPP (see section 7.6 of this NASA Technical Standard). 

[Rationale