InspectionControl_StampAndMarkingMaterials

Stamping and marking materials

Any Inspection Control system must regulate which stamping materials are appropriate for use on certain items. Here some commonly used stamping materials:

  • Stamps
  • Decals
  • Seals
  • Torque wax
  • Paints
  • Signatures
  • Inspection pliers
  • Electronic Data Entries.

 

Some samples:

*Basic figures for type of stamps courtesy of NASA STEP [1].

 

Important process points such as: source and receiving inspection; in process fabrication and inspection; end-item fabrication and inspection; and end-item testing, storage, and shipment, need to be signified to indicate that articles and materials have undergone those processes. The use of appropriate material for stamps in each step is very important.

 

Stamp traceability

Each stamp in use must be traceable back to a unique responsible individual and records must be maintained to associate personnel with specific stamps. This is critical to keep the integrity of the personal warranty.

Stamp Traceability

Figure 1: Stamp Traceability. Image courtesy of NASA STEP [1].

 

It is important to secure unissued stamps to avoid unauthorized use. For instance, at NASA: “Stamping material issued to personnel who are transferred or terminated are returned and not reissued for an appropriate period, usually six months or more. When stamping material becomes worn or damaged, these stamps are destroyed when replacement stamps are issued” [1].

It is important that in the development team, the use of any stamp by an individual other than its recorded holder be specifically prohibited. Periodic checks should be in place to make sure that stamps are handled by the individual to whom they are issued and that they are not damaged or altered in any way.

 

To illustrate these issues and guidelines, we are going to present some of the specific NASA requirements related to stamps and their use. Here are some examples [1]:

 

In NPR 8735.2, Section 2.4.5.3 states [1]:

 

“Where product assurance accomplishment is attested by application of stamps to inspected supplies, the stamp shall not be applied in a manner prohibited by drawings or specifications or which may degrade the quality of the product.”

 

And NPR 8735.2, Section 2.4.5.1 says [1]:

 

“Signatures, stamps, and data entries shall identify the discrete item examined (including any unique product identification/traceability information), process witnessed, or record verified (Requirement). Such documentation may be accomplished utilizing the contractor’s approved electronic system for indicating inspection status, or by the application of a signature or stamp to prerecorded planning documents or records (e.g., material test data) which contain this information. “

 

 

Here’s an example of the Traceable Control Stamp Requisition and Receipt form from NASA [1]:

Stamp requisition document sample

Figure 2: Traceable Control Stamp Requisition and Receipt form of NASA. Image courtesy of NASA STEP [1].

 

The company GBC Inc [10], provides an interesting "Quality Assurance Manual" [11], where one can find templates for stamp requisition, control and inspection records (forms 2.1.1, 2.2.1 and 2.2.2).

 

At NASA, the procedures for lost, stolen or misplaced stamps are [1]:

  • Stamp holder notifies supervisor with stamp number, description and date lost.
  • Lost stamp becomes invalid
  • If one stamp in a set is lost, the set usually becomes classified as lost.

 

Stamp set sample

Figure 3: Missing stamp on set. Image courtesy of NASA STEP [1].

 

In case a stamp is lost, procedures should require that the holder immediately notify his supervisor, providing a stamp control number, a description of the stamp and the date it was lost. Numbers, letters or any other identification symbol in use on the stolen, lost or misplaced stamps must be withdrawn from use. Inspection and records personnel must be aware of the situation and help to supervise that the listed stamps are not being used by unauthorized personnel.

If stamps previously misplaced or stolen are later recovered, they should be returned to the central stamp custodian and destroyed. Replacement stamps are normally assigned a different number or other type of additional identifier if the same number is used. It is a good practice that if one stamp in a set is lost, then the entire set should be classified as lost and the remaining stamps be turned in.

 

Sample of a lost Quality Status Stamp Notice from NASA [1].

Stamp requisition document sample

Figure 4: NASA Quality Status Stamp Notice. Image courtesy of NASA STEP [1].

 

Stamp application

A Stamp Control system regulates the way stamps are applied to certain items. It is critical that the stamping method used:

  • Does not damage the item
  • Does not hamper its function
  • Does not impede the product’s manufacturing process. 

 

Drawings usually indicate how a stamp must be applied in accordance with controlled methods of identification marking. Marks that can have a potential effect on product quality, like etching marks on a metal part, must be used only as specified by applicable drawings or specifications. When sheet or rolls that are normally issued by cutting portions from raw stock are used, they ought to be marked so that identification is retained until issue of the final portion. In case of inspection of age-sensitive materials and those requiring retest or re-inspection will be reflected directly on the articles or their containers.

One more time: Stamping should not interfere with product performance or the future processing or identification of the product.

 

To summarize, during application [1]:

  • Stamp direct markMarks applied directly to the materials are applied in accordance with plans
  • Marks should not affect product quality
  • Sheet and roll stock should be marked so identification is maintained
  • Marking should not interfere with product performance or future processing

 

 

 

 

Figure 5: Stamp on steel, Image courtesy of NASA STEP [1].

 

Misuse of stamps

The organization or team procedures should cover the misuse of stamps and the personnel disciplinary consequences. These procedures should point out that: “Making a traceable stamp available for use by any person other than the one to whom the stamp is assigned, or intentional damage to a stamp, will be considered misuse of the stamp” and will lead to disciplinary action.

 

Other misuses that can produce disciplinary actions are:

  • Unauthorized incomplete
  • Substandard workmanship
  • Unauthorized rework or substitutions
  • Nonconforming articles
  • Damaged parts
  • Operations for which the holder has not been certified
  • Failure to use a stamp when required

 

Stamp holders maintain control of traceable control stamp by keeping their assigned stamps in their possession or placing the stamp in a secure location when not in use [1].

 

 

Misuse of StampsRemember, accepting any of the following is considered stamp misuse by NASA [1]:

  • Unauthorized incomplete work
  • Substandard workmanship
  • Unauthorized rework or substitutions
  • Nonconforming articles
  • Damaged parts
  • Operations for which the holder has not been authorized
  • Failure to use a stamp when required

Figure 6: Stamp misuse, Image courtesy of NASA STEP [1].

 

 

 

 

Electronic stamping

Electronic Stamping

The “Build Paper” or “Build Record” is defined as the “Status of inspection and test in the fabrication and assembly instructions”. This build paper should present a specific location for a stamp to be registered and show the item status. With modern electronics, it is only natural to use this type of hardware to at least partially automate the creation of build papers. The electronic systems must also have provisions to show the inspection and test status, just as the paper system has a place for a stamp.

 

To safeguard the integrity of status entries, electronic stamping normally uses a personally assigned badge for bar coding or a password keyboard entry for each responsible inspector or operator. For instance, in case of NASA, for systems used by contractors, the system must also provide for entry by NASA or its representative at Government Mandatory Inspection Points.

 

 

Electronic Stamping Sample ImageNo matter the media used, signifying the status of an inspection or test electronically carries the same level of responsibility as applying a stamp or signature. Inspection marking of computerized records can be accomplished with "mouse and keyboard" entry or with a personally assigned badge that can use bar coding for input [1].

 

 

 

When a person having access to the system is reassigned or terminated, his/her access must also be terminated.

 

When is it important to update status electronically [1]?

  • When article is ready for inspection or testing
  • When article was inspected or tested
  • Status of inspected of tested article

 

 

Electronic access responsabilityNever forget: Electronic access carries the same responsibility as traditional stamping!

 

Even with a growing tendency to use electronic systems for stamp data control, granting a password or using a bar coding badge for making automated entries should follow the same criteria to those for issuing a traditional stamp.

 

 

 

 

The operator or inspector accepts the following responsibilities and conditions [1]:

 

  • The electronic entry is a personal warranty that the activity was performed in accordance with the requirements and inspected with requisite quality
  • The inspection was based on physical and/or objective evidence of compliance, and the condition was personally observed.
  • If unable to warrant an operation because of errors or uncertainty in the paperwork, the work will be stopped and the situation will be brought to the attention of management.
  • Specific entries to the system may be required depending on system instructions.
  • The original entry will not be released, cleared, or voided until the paperwork is satisfactory.
  • The password or bar coding badge will be safeguarded as a stamp would be. A personal password or bar-coding badge will never be used for entry purposes by another person for any reason.
  • If qualification for entry involves certification and the certification lapses or is voided, entries will be immediately stopped and the situation will be brought to the attention of management (preferably prior to the lapse).