Technical insight
Rotor Identification Marking: Approve the Method, Location and Sequence
Before a supplier applies identification to a rotor, obtain approval for how, where and when it will be marked. Ask the design authority to release a marking definition that the manufacturing and inspection teams can follow. A requirement to identify the part should not become permission to choose an available surface or an unspecified laser process.
By Geetai Precision
- Published
- Updated
Start with a drawing-controlled marking definition
NASA/JSC PRC-9002 Rev. L requires a drawing note identifying the marking method and a drawing-defined location. Its location review includes potential damage to a critical surface and visibility at later assembly stages. These are requirements of that cited document, not automatically requirements for a commercial rotor. [1]
NASA/JSC PRC-9003 Rev. D separately addresses laser marking and engraving. It calls for drawing-defined character location and qualification for each material and configuration; its evaluation includes the marked area and surrounding surfaces. [2]
Use these references to frame the approval discussion. Ask the responsible engineering reviewer to assess the actual alloy and condition, selected process and proposed zone. Do not infer an acceptable stress location, marking depth or equipment setting from a photograph or a general process name.
A marking approval worksheet
Use this original purchasing worksheet with the released drawing. Its entries are editorial recommendations for making decisions visible; they do not select a marking method or impose NASA procedures on the order.
| Decision | Supplier proposal | Approval to obtain |
|---|---|---|
| Method | Name the proposed process and governing procedure; identify any alternative separately. | Design authority approves the exact proposal, including any required process qualification. |
| Location | Show the permitted marking boundary and orientation on controlled geometry. | Resolve excluded functional surfaces and any ambiguous boundary before marking. |
| Mark content | Specify the actual characters or data, size requirements and legibility check. | Approve the marking layout against the drawing; do not let an example become production data. |
| Sequence | Place marking relative to machining, finishing, cleaning, inspection and balancing, where applicable. | Approve the route and any checks required after marking or later operations. |
| Release evidence | Define the location/content record, process reference and required surface checks. | Name the reviewer and disposition path for an incorrect, missing or out-of-zone mark. |
Review the operation sequence before work starts
The cited PRC-9002 Rev. L places marking after final surface finishing as a general instruction but gives different timing for particular impression methods. PRC-9003 Rev. D also addresses finishing sequence and the legibility of marks beneath a finish. The examples show why a single generic sequence should not be copied across processes. [1][2]
Before machining release, ask whether the approved marking zone must remain accessible and whether later material removal would affect it. Before the marking operation, reconcile the drawing, marking layout, procedure revision and actual part condition. If the route differs from the approved plan, hold the marking step for technical disposition.
Ask the technical owner to decide which checks follow marking and which later operations require another review. Record those decisions alongside the route. Keep cleaning acceptance, dimensional acceptance and balancing scope as separate agreed requirements; do not assume that a readable serial number closes them.
Handle an unclear zone or changed method
For example, suppose the drawing requests identification but gives no marking location, and the supplier proposes laser marking on a convenient hub face. Request an annotated proposal showing the method, zone, part condition and processing stage. Send it to the design authority before applying the mark. This is a hypothetical clarification, not an approved location.
If the proposed layout will not fit inside the approved zone, request a revised layout or an authorized alternative. Do not shrink characters, move onto another face or repeat a failed mark without disposition. Ask the reviewer to specify how an existing marking error will be handled; this guide does not authorize removal or repair.
Close the marking decision at release
Request the agreed evidence that the correct information was applied in the authorized zone using the approved instruction. A photograph can support location and appearance review, but ask for the separately required process and surface-condition evidence. Record any deviation and its authorized disposition before closing the marking item.
For a rotor inquiry, send the released drawing and model, material and finish requirements, proposed marking layout and the unresolved sequence questions. Use the rotor drawing-review route for the component discussion and the inspection route for the requested release records.
Frequently asked questions
Is laser marking automatically suitable for a rotor?
Ask the design authority to approve the specific material, process and location. The cited laser specification uses material- and configuration-specific qualification; the process name alone does not approve a particular rotor.
Can a supplier move the identification to a clearer surface?
Submit the proposed location change for approval before marking. If no direct mark is authorized, request a controlled identification alternative and its handling instructions rather than choosing another surface.
Related review paths
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References
- Process Specification for Part Marking — PRC-9002 Rev. L, December 2019 — NASA Johnson Space Center. Accessed 2026-11-01T01:18:30.706Z.
- Process Specification for Laser Marking & Laser Engraving — PRC-9003 Rev. D, June 2020 — NASA Johnson Space Center. Accessed 2026-11-01T01:18:30.706Z.
- Structural Engineering Division — NASA Process Specification Index — NASA Johnson Space Center. Accessed 2026-11-01T01:18:30.706Z.
- Owner-supplied multi-row rotor visual reference — Geetai Precision — owner-supplied visual reference. Accessed 2026-11-01T01:18:30.706Z.
