Stamp design and significance
As mentioned in the previous sections, it is very important that personnel who are responsible for inspection and stamping keep proper controls and understand the importance of personal warranty. It is also important that personnel in all phases of the product life cycle be able to recognize, read, and interpret status stamps and their origins and meanings.
Figure 1: Image courtesy of NASA STEP .
As part of an Inspection Control system, an up-to-date description and explanation of the significance of all stamps is maintained. Thanks to NASA STEP SMA-QE-WBT-252 , we can see some examples of some common stamps and their purposes used by NASA.
Contractor stamp designs
Following we will illustrate examples of Contractor stamp designs used for product or process acceptance, withholding, or rejection, as well as test equipment certification and calibration .
According to NASA STEP : "The designs of contractor stamps for fabrication and inspection should be distinctly different. Contractor stamps may not exhibit the designation NASA, abbreviations of any NASA installation, or the designation or abbreviations of any International Partner government without NASA consent".
The acceptance stamp is used for the following purposes:
Figure 2: Acceptance Stamp sample, Image courtesy of NASA STEP .
Material review stamps
According to NASA STEP : "Issuance of Material Review stamps is limited to Material Review personnel, Product Assurance management, work coordinators, Product Assurance field representatives, source inspectors, and other Product Assurance personnel as approved by the MR (Material Review) manager".
|Withholding (“D”) Stamp||Indicates noncompliance with drawing and/or specification requirements when material review action is required
|Acceptance (Triangle) Stamp||Indicates MR acceptance of a nonconformance on a withheld (“D” stamped) item
|Rejection (“R”) Stamp||Indicates MR rejection of item
Figure 3: Rejection Stamp samples, Image courtesy of NASA STEP .
Specific acceptance stamps
According to NASA STEP : "These stamps are used by inspectors, certified in specific operations or processes, to indicate that those operations or processes (for example, X-ray, soldering, heat treatment, or various nondestructive tests), in a planned fabrication cycle, adhere to the applicable planning, drawing, and specification requirements".
|Dye Penetrant Stamp (PD)||Indicates acceptance of material by dye penetrant inspection.
|Fluorescent Penetrant Stamp (PF)||Indicates acceptance of material by fluorescent penetrant inspection.
|Magnetic Stamp (M)||Indicates acceptance of material by magnetic inspection.|
|Heat Treat Stamp (HT)||Indicates acceptance of material to applicable heat treatment requirements.
|Heat Treat Age Stamp (HTA)||Indicates acceptance of material to applicable heat treat age requirements.|
|Pressure Test Stamp (PT)||Indicates acceptance of material by pressure testing.
|Radiographic Testing Stamp (RT)||Indicates acceptance of material by radiographic testing.|
|Ultrasonic Stamp||Indicates acceptance of material by ultrasonic testing.
|Certification Stamp (TEC)||Used exclusively by Quality Engineering to indicate acceptance of test equipment certification.|
|Calibration Stamp (CAL)||Indicates calibration acceptance of a measuring device for a specified period of time. Issuance of this stamp is limited to individuals designated and approved by Calibration Laboratory supervision.
|Leak Testing Stamp (LT)||Indicates acceptance of material by leak testing.
Figure 4: Special Acceptance Stamp samples, Image courtesy of NASA STEP .
In many cases, aerospace projects including CubeSat developments are going to deal with government and space agencies. It is important to overview the anatomy of the NASA Stamps as a good example of what to expect in terms of inspection if dealing with a top agency as NASA, and also gives us some ideas of the type of inspection stamps that can be designed and used in any project. Let's review the anatomy of a typical NASA stamp 
NASA stamps usually include the installation, the individual inspector, and the "NASA" designation :
- The upper area of the stamp contains the symbols for NASA field installations.
- The center area of the stamp has the designator "NASA."
- The lower area of the stamp contains a three-character alphanumeric number assigned to the individual to whom the stamp is issued.
In the case of NASA, the field installation list includes: Ames Research Center A; Dryden Flight Research Facility F; Goddard Space Flight Center G; Johnson Space Center S; Kennedy Space center K; Langley Research Center R; Glenn Research Center C; Marshall Space Flight Center M; Stennis Space Center T; Wallops Flight Facility W.
Let's review: click on the hotspots in the image below to review the anatomy of a typical NASA stamp.
Typical NASA quality stamps
Thanks to NASA STEP SMA-QE-WBT-252 , we can see some typical NASA quality stamps:
|Conformance Stamp||A triangle stamp indicates that the article and/or documents satisfy NASA requirements and conform to prescribed criteria.
|Nonconformance Stamp||A hexagonal stamp indicates that articles and/or documents have been inspected and/or tested, but do not conform to requirements. Such articles and documents are subject to further corrective actions, inspections, tests, investigations, processing, or contract actions.
|Void Stamp||A “D”-shaped stamp indicates that previous contractor and/or Government inspections, tests, and accompanying documents are void.|
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