material property performance goals 
(e.g., fatigue life). 

Variations of reference parts (i.e., small complex parts that push the limits of the AM process) are 
used to understand surface texture and detail resolution of an AM system. When the AM process is 
pushed to the limits of its operational capability, it will become more sensitive to perturbations in 
operational parameters. By monitoring the reference parts for variations, an AM part producer will 
have an indication of process capability limitations, as well as early indications of process change 
during production. The reference part is intended to provide quantitative criteria to judge process 
performance and repeatability in development of QMPs, AM machine qualification, and AM part 
production. When used for such purposes, reference part metrics defined by the QMP process are 
used as acceptance criteria. 

5.5.3.4.1 Surface Texture Metrics and Acceptance Criteria 

[AMR-56]  For each QMP-A and QMP-B, consistent measures of as-built surface texture and detail 
resolution with associated acceptance criteria shall be defined. 

[Rationale:  To maintain consistency in the AM process, surface texture and detail resolution for 
process requalification or the development of Sub-QMPs are evaluated with reference parts using 
the acceptance criteria of the applicable QMP. In many cases, consistency in surface texture and 
detail are critical to part performance.] 

 Mechanical Properties 

[AMR-57]  Mechanical properties shall be evaluated for all candidate material processes with, at 
minimum, the specimen quantities according to Tables 13, 14, 15, or 16, as applicable.   

[Rationale:  Mechanical property performance is a fundamental measure of the quality of the 
candidate material process and forms the basis for evaluation of material engineering equivalence 
for the applicability of material allowables and design values.] 
Per section 5.5 of this NASA Technical Standard, minimum specimen quantities apply to each 
individual energy source in the machine.  
Table 13 is applicable to evaluate QMPs in metals of Classes A, B, or C.   
Table 14 is applicable to evaluate Sub-QMPs in metals of Classes A, B, or C, and for builds used 
for SPC supporting continuous build operations for witness sampling. 
Table 15 is applicable to evaluate QMPs in polymers of Classes B or C. 
Table 16 is applicable to evaluate Sub-QMPs in polymers of Classes B or C and for builds used for 
SPC supporting continuous build operations for witness sampling.  


Table 13—Minimum Mechanical Property Tests for Metal QMP Builds 

QMP 
Item Property 
ASTM 
Standard* Quantity Notes 
      QMP-A QMP-B QMP-C   
1 Tensile E8/E8M 15 15 6 
Survey of build area and materials using 
machine tensile specimens meeting 
requirements of sections 5.5.3.1.a and 5.5.3.1.b 
of this NASA Technical Standard. 
2 
Tensile, with 
Process 
Restart 
E8/E8M 5 5 - 
Required if process restart is allowed. Tensile 
testing of process restart interface characterized 
by restarting in sample gauge section of 
machined specimen. Item 2 tests not required if 
restart is included in testing for Item 1. 
3 
High Cycle 
Fatigue 
(HCF) 
E466 10 5 - 
For QMP-A, five (5) tests to MPS PCRD 
fatigue condition, and five (5) tests at cyclic 
stress range producing failure >10^6 cycles 
that replicate R-ratio and stress range of 
existing MPS data, enabling comparison. For 
QMP-B, five (5) tests to MPS PCRD fatigue 
condition. 
4 
Low Cycle 
Fatigue 
(LCF) 
E606/E606M 5 5 - Five (5) tests at a cyclic strain range 
represented in MPS data. 
5 
Fatigue, with 
Process 
Restart 
E466, 
E606/E606M 5 5 - 
Required if process restart is allowed. Fatigue 
testing of process restart with HCF or LCF, 
five (5) tests at the MPS PCRD fatigue 
condition. Item 5 tests not required if restart is 
included in tests from Items 3 and/or 4. 
6 Fracture 
Toughness E1820, E399 3 0 - Tests with crack in worst-case orientation 
relative to build plane. 
7 Tensile (at 
Temperature) E21, E1450 6 3 - 
Three (3) tests per temperature at two or more 
temperatures—either the high and low 
bounding temperatures of the MPS or other 
applicable temperatures. 
8 Customized 
QMP As specified 2 2 - 
Test at conditions defined by the candidate 
metallurgical process required for acceptance; 
minimum two (2) tests at condition. 
*Other test standards approved by the CEO may be used. 


Table 14—Minimum Mechanical Property Tests for Metal Sub-QMP and SPC Evaluation 
Builds 

Sub-
QMP and 
SPC Item Property 
ASTM 
Standard* Quantity Notes 
      QMP-A QMP-B QMP-C   
1 Tensile E8/E8M 10 10 4 Survey of build area locations using 
machined tensile specimens. 
2 
Tensile, 
with Process 
Restart 
E8/E8M 5 5 - 
Required if process restart is allowed. 
Tensile testing of process restart interface 
characterized by restarting in sample gauge 
section of machined specimens. Item 2 tests 
not required if restart is included in testing 
for Item 1. 
3 
High Cycle 
Fatigue 
(HCF) 
E466 5 5 - Five (5) tests to MPS PCRD fatigue 
condition. 
4 
Low Cycle 
Fatigue 
(LCF) 
E606/E606M - - - Not required for sub-QMP (only QMP). 
5 
Fatigue, 
with Process 
Restart 
E466, 
E606/E606M 5 5 - 
Required if process restart is allowed. 
Fatigue testing of process restart with HCF 
or LCF, five (5) tests at the MPS PCRD 
fatigue condition. Item 5 tests not required 
if restart is included in tests from Item 3. 
6 Fracture 
Toughness E1820, E399 2  - Tests with crack in worst-case orientation 
relative to build plane. 
7 Tensile (at 
temperature) E21, E1450 - - - Not required for sub-QMP (only QMP). 
8 Customized 
QMP As specified 2 2 - 
Test at conditions defined by the candidate 
metallurgical process required for 
acceptance; minimum of two (2) tests at 
condition. 
*Other test standards approved by the CEO may be used. 


Table 15—Minimum Mechanical Property Tests for Polymeric QMP Builds 
QMP 
Item Property ASTM Standard* Quantity Notes 
      QMP-A QMP-B QMP-C   
1 Tensile D638/D5766/D6742 
Not 
Applicable 
15 6 
Survey of build area and materials 
using machined tensile specimens from 
“hot” and “cold” process variants  
2 
Tensile, with 
Process 
Restart 
D638/D5766/D6742 5 - 
Required if process restart is allowed. 
Tensile testing of process restart 
interface characterized by restarting in 
sample gauge section of machined 
specimen. Item 2 tests not required if 
restart is included in testing for Item 1. 
3 Density See commentary 5 -  
4 Flexural D790 3 - 
Method that determines the modulus of 
elasticity and flexural strength of 
reinforced and unreinforced plastic. 
5 Compression D695/D6742/D6484 3 - 
Method used in determining a 
material’s modulus of elasticity and 
compressive offset yield strength. 
6 Sustained 
load D2990 3 - Stiffness, offset bearing strength, and 
ultimate bearing strength. 
7 Customized 
QMP As Specified 2 - 
Test at conditions defined by the 
candidate material process required for 
acceptance, minimum two (2) tests at 
condition. 
*Other test standards approved by the CEO may be used. 

The preferred methods for density measurements are still evolving. Standard test methods that may 
be considered are ASTM D792, ASTM D1505, ISO 1183, and void sampling in cross-section.  


Table 16—Minimum Mechanical Property Tests for Polymeric Sub-QMP and SPC 
Evaluation Builds 
Sub QMP 
and SPC 
Build 
Item Property 
ASTM 
Standard* Quantity Notes 
      QMP-A QMP-B QMP-C   
1 Tensile D638/D5766/ 
D6742 
Not 
Applicable 
10 4 Survey of build area locations using 
machined tensile specimens. 
2 
Tensile, with 
Process 
Restart 
D638/D5766/ 
D6742 5 - 
Required if process restart is allowed. 
Tensile testing of process restart 
interface characterized by restarting in 
sample gauge section of machined 
specimens. Item 2 tests not required if 
restart is included in testing for Item 1. 
3 Density See 
commentary 3 - Not required for sub-QMP (only QMP). 
4 Flexural D790 3 - 
Method that determines the modulus of 
elasticity and flexural strength of 
reinforced and unreinforced plastic. 
5 Compression D695/D6742/ 
D6484 3 - 
Method used in determining a material’s 
modulus of elasticity and compressive 
offset yield strength. 
6 Sustained 
Load D2990 3 - Not required for sub-QMP (only QMP). 
7 Customized 
QMP As Specified 2 - 
Test at conditions defined by the 
candidate material process required for 
acceptance, minimum two (2) tests at 
condition. 
*Other test standards approved by the CEO may be used. 

The preferred methods for density measurements are still evolving.  Standard test methods that may 
be considered are ASTM D792, ASTM D1505, ISO 1183, and void sampling in cross-section. 


 Qualified Material Process Record 

[AMR-58]  A candidate material process shall become fully qualified (i.e., a QMP) when: 

a. A configuration-controlled record is established containing the complete definition of the 
QMP and all necessary supporting information substantiating that the qualification requirements of 
section 5 of this NASA Technical Standard have been satisfied. 

b. The CEO has verified it to be complete and satisfactory. 

c. Items (a) and (b) are documented and controlled by the QMS. 

[Rationale:  The QMP is a core governing document of AM process control and, as such, requires 
proper substantiation, documentation, and approval.] 

See section 5.2 of this NASA Technical Standard for additional information regarding candidate 
material processes and unique QMPs. 

This requirement intends the following:  Once documented, the CEO approves QMPs; and 
following this approval, a QMP record defines a fixed process for which changes are prohibited 
without formal reevaluation and approval.  

The development of candidate material processes and execution of the evaluations to qualify them 
as QMPs are typically the responsibility of the AM part producer. A partnership between the CEO 
and the AM part producer, if not the same entity, is required for successful implementation of these 
requirements. 

A QMP may be treated as proprietary information. NASA may review a QMP and its supporting 
data at any time. 


5.6 Registration of a Candidate Material Process to an MPS 

[AMR-59]  Each candidate material process for a QMP-A or QMP-B shall be registered to an MPS 
through confirmation of the properties listed in Table 17, Properties and Controls to Register a 
Candidate Material Process to an MPS, that have been tested per Tables 13 through 16. 

Table 17—Properties and Controls to Register a Candidate Material Process to an MPS 
Property Metals Polymers 
Feedstock specification and feedstock controls are the same as 
those in the MPS. X X 
Documentation is available to verify that the material process 
definition was established and adhered to continuously during the 
development of evaluation materials. X X 
Microstructural characteristics are consistent with those of the 
MPS. X X 
Tensile strengths and ductility are accepted to the tensile PCRDs 
of the MPS. X X 
Measured high cycle fatigue life is accepted to the fatigue PCRD 
of the MPS. X  
Measured low-cycle fatigue life is consistent with MPS data. X  
Measured fracture toughness is consistent with MPS data. X  
For QMP-A and QMP-B, if applicable, tensile properties at 
temperature are consistent with MPS data. X  
Measured density is consistent with density of MPS data.  X 
Measured flexural modulus of elasticity and/or flexural strength is 
consistent with MPS data.  X 
Measured compression modulus of elasticity is consistent with 
MPS data.  X 
Measured sustained load performance is consistent with MPS 
data.  X 
Documentation substantiating this confirmation will be 
configuration controlled within the QMS and recorded within the 
qualified material process record. X X 

[Rationale:  The material property registration process provides traceability between process 
capability as demonstrated through QMP qualification and the material property values that will be 
defined by the MPS and used to determine design manufacturability when using that QMP for a 
production build. Due to the sensitivity of the AM process implementation, it is not legitimate to 
assume material allowables or design values associated with previously used but differently 
controlled AM processes are applicable. The registration process evaluates the key failure 
mechanisms for design/material/process compatibility (e.g., strength, ductility, cyclic damage, and 
fracture toughness). While often correlated, these failure modes may act independently.] 


Upon successful registration, the material property data should be added to the MPS database. The 
CEO is responsible for the registration process and eventual final approval of the candidate process 
as a QMP. For property evaluations where PCRD criteria are not established, candidate data are 
determined to be consistent with the MPS if the average result of the candidate data lies within the 
statistical range of existing data in the MPS. If outlier data exist, such test results and associated 
specimens should be evaluated to determine cause. If outlier data are the result of systemic process 
issues, then registration should be withheld pending correction and reevaluation. Other metrics for 
determining data to be consistent may be proposed. The CEO has latitude in making the final 
determination of registration of a material process to an MPS. If aspects of registration data do not 
fully meet the criteria above but the MPS appropriately accommodates the difference, such 
rationale may be provided in the QMP record. If the data do not register to the MPS, then the CEO 
may opt to gather additional data, continue to improve the process, or develop a new MPS that 
represents the measured material performance. Note, PCRDs are not required for QMP-Cs. 

As per the definition, the PCRD is a simple statistical model used to create acceptance criteria for 
evaluation of witness specimens used to monitor the AM process. The goal of the PCRD is to employ 
SPC to protect the process from drift by keeping the properties consistent with those in the MPS. 
The use of the PCRD in witness testing justifies the continued validity of the material allowables 
during ongoing AM operations. Control charts use acceptance limits for visualizing process 
stability and identifying production runs or units whose attribute(s) exceed the limits. Many times it 
is important to define multiple PCRDs per the QMP. 

It is recommended that properties not required for registering a candidate material process to the 
MPS still be measured and controlled when important to the design. An example is provided with 
respect to the fracture toughness of a polymeric material. Although a requirement is not placed for 
measuring this property of a polymer for successful MPS registration (by virtue of implied 
structural considerations of Class B parts), characterizing fracture toughness provides insight into 
plane-strain fracture behavior. To assess the correlating properties, conducting ASTM D5045 will 
indicate a polymer's rate of crack propagation through its plane-strain energy release rate. The 
applicability of this investigation varies with the polymer and may be more relevant to those 
exhibiting brittle fracture (e.g., a filled polyamide).  

For example, in metallic AM builds, four PCRDs are defined for each MPS:  ultimate tensile 
strength (UTS), yield strength, elongation, and fatigue life at a fixed cyclic stress condition. The 
choice of defined PCRDs may change with AM process and material depending on which properties 
are determined most useful to process control. The PCRDs and their associated acceptance criteria 
are best documented in a manner that allows for occasional revision and sustained use as witness 
specimen testing acceptance criteria for part acceptance. 

 Bootstrapping a QMP and MPS 

When new AM processes are first established, an MPS may not yet exist to conduct the registration 
process. In such cases, the material test data generated to produce the QMP are also used to 
generate the initial MPS (i.e., bootstrapping), and the QMP is registered to the new MPS by default. 


Additional data generated from the QMP are used to populate preliminary MPS PCRDs and other 
material properties to enable registration of additional QMPs. 

In these cases, the QMP can be executed with a single feedstock lot to create the initial MPS, but 
additional lot and variability requirements are governed by the MPS requirements in section 6 of 
this NASA Technical Standard. 

5.7 Qualified Material Process Record 

[AMR-60]  A candidate QMP shall become fully qualified (i.e., a QMP) when: 

a. A configuration-controlled record is established containing the complete definition of