Changing one hole can affect more than one report row. It may move a mounting interface, require a new fixture, alter a bend sequence or change access for installed hardware. Conversely, some document changes may not alter the manufactured item at all.
The decision to perform a new, full or partial first article should follow the applicable customer requirements and a recorded change assessment. For OEM sheet-metal assemblies, the useful question is not “Did the revision letter change?” but “Which previously accepted evidence still describes the new manufacturing configuration?”
Keep the customer’s rule visible
First-article requirements differ between programs. Some buyers specify their own forms and triggers; others invoke a particular standard. Do not assume that an aerospace rule automatically governs a medical or industrial equipment order.
The SAE AS9102C overview identifies requirements for performing and documenting FAI and makes clear that customer and applicable requirements remain relevant. Use the actual contractually specified edition and customer instructions when determining scope.
This article is an engineering change-review framework, not a substitute for those requirements. The drawing authority and designated customer quality contact should resolve any uncertainty before parts are released.
Map the change beyond its visible geometry
Start with the revised drawing or model, but also inspect manufacturing inputs. Material, thickness, finish route, hardware source, tooling, production location or inspection method can change the relevance of earlier evidence.
An unchanged part number is not proof of an unchanged process. Likewise, a moved dimension note may not represent a physical product change. Record what changed, why it matters and which records support the conclusion.
| Change category | Impact to investigate | Evidence to agree |
|---|---|---|
| Hole, slot or flange geometry | Mating pattern, clearances and downstream locating | Affected dimensions and interface checks |
| Material, thickness or finish route | Forming, joining, hardware and final dimensions | Relevant material, process and finished-state records |
| Tool, program or manufacturing source | Whether the accepted process is still represented | Customer-defined reassessment and inspection scope |
| Document-only clarification | Whether product or acceptance actually changes | Recorded review and authorized disposition |
Define what a partial submission must prove
A partial first article should not mean inspecting only the feature someone noticed first. Identify the affected characteristics and the dependencies that could change with them.
For an illustrative cover with a moved mounting slot, the review might include the slot’s location, its relationship to the installed mating part and tool access after assembly. If the manufacturing sequence also changes, additional surfaces may need checking. The actual scope depends on the design and the customer rule.
Link the new submission to an identifiable accepted baseline. List the evidence being retained, the evidence being replaced and the reason each remains applicable. If there is no suitable baseline, do not describe an incomplete new submission as a partial update merely to reduce paperwork.
Bring fixtures and inspection instructions into the review
A fixture can become obsolete even when most dimensions stay the same. A relocated datum target, a modified mounting face or a changed finish allowance can affect the way the part seats.
Update the inspection program, drawing balloons, fixture references and work instructions consistently. If a new measurement method replaces an earlier one, evaluate its suitability and any necessary correlation. A template copied from the previous revision may otherwise report the wrong acceptance conditions accurately.
Control the transition between old and new stock
Identify which work in progress, finished goods and scheduled releases use each revision. Define whether older stock remains usable, needs rework or must be segregated pending a decision.
Do not treat first-article approval as permission to mix revisions. The purchasing release, BOM and assembly instructions still need to identify the ordered configuration. Approved deviations should have a clear affected scope rather than becoming an informal permanent exception.
Where a production interruption or equipment move raises questions about the earlier baseline, review it against the specified customer rules. Do not invent a universal time threshold for all sheet-metal programs.
Close the review with an explicit release decision
The change record should state the affected configuration, agreed inspection scope, required approvals and the status of remaining actions. Keep first-article approval separate from authorization to ship a particular production lot.
For the broader distinction, see first article versus routine lot inspection. Together, these controls let the buyer preserve valid evidence without assuming that either a revision letter or one successful sample answers every subsequent release question.
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