Quality
A first article inspection report is the difference between “we checked it” and “here is what we measured”. Read it before the batch, not after the complaint.
Key takeaways
- FAI is the first part measured against the drawing before the run continues.
- A useful report shows nominal, tolerance, actual value and the instrument used.
- A caliper cannot prove a ±0.002 mm tolerance; the instrument must match the callout.
- Check part number and revision first — the wrong revision invalidates the report.
- If a value is out, the report should show the correction and re-check.
What FAI actually is
The first part off the run is measured against every characteristic on the drawing. If it passes, the run continues. If it fails, the process is corrected before more material is cut. The report is the record of that decision.
It is not a certificate. It is a measurement document tied to a specific part number, revision, drawing and date.
What a useful report looks like
| Characteristic | Nominal | Tolerance | Actual | Instrument | Result |
|---|---|---|---|---|---|
| Pivot bore | Ø8.000 | +0.010 / 0 | 8.006 | CMM | Pass |
| Overall length | 120.00 | ±0.05 | 120.03 | Micrometer | Pass |
| Flatness, face A | 0 | 0.02 | 0.008 | CMM | Pass |
| Thread | M6 × 1 | 6H | Go / No-Go | Thread gauge | Pass |
| Surface finish | Ra 0.8 | max | Ra 0.62 | Profilometer | Pass |
| Wall thickness | 2.00 | ±0.05 | 2.07 | Micrometer | Fail |
Illustrative example. A real report carries the part number, revision, inspector and date.
Notice the failed line. A report that shows every value exactly in the middle of the tolerance is a report to question — real measurements have variation.
How to read it in two minutes
- Part number and revision. Does it match the drawing you approved?
- Scan for out-of-tolerance values. Any red line stops the run.
- Instrument vs tolerance. A caliper cannot prove ±0.002 mm; a CMM, micrometer or pin gauge can.
- “Not measured” lines. Ask why, and who accepted the risk.
- Date and inspector. Confirm it is the first article, not a sample pulled later.
Instrument capability: what can prove what
| Instrument | Typical resolution | Can prove |
|---|---|---|
| Caliper | 0.01 mm | General dimensions, not tight tolerances |
| Micrometer | 0.001 mm | Diameters, thicknesses, ±0.005 mm and coarser |
| Pin gauge | 0.001 mm | Hole size and fit |
| Thread gauge | Go / No-Go | Thread form, not pitch diameter |
| CMM | 0.001 mm and better | Position, flatness, profile, tight tolerances |
| Profilometer | Ra/Rz | Surface finish callouts |
Red flags in an FAI report
- No part number or revision.
- Values with no instrument listed.
- Every measurement exactly at nominal.
- Critical features marked “not measured” with no explanation.
- A report dated after the batch shipped.
- No pass/fail summary.
What to do if a characteristic is out
The supplier should stop the run, identify the cause, correct the process and re-measure. The report should show the original value, the correction and the new value. If the part cannot be corrected, the supplier should remake or credit it — before the rest of the batch is cut.
What GY provides
Every first article is measured on the CMM before the run continues, and the report ships as a PDF. Critical features are measured with the instrument that can actually prove the tolerance. We do not hold ISO 9001; if your RFQ requires a certificate, we say so up front.
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FAQ
What is a first article inspection report?
The first part from a run is measured against every characteristic on the drawing before the rest of the batch is cut. The report lists the nominal, the tolerance and the actual measurement.
When should I ask for an FAI?
On a new part, a new program, a changed drawing, a new material or a new finishing process. On repeat orders, a first-off check plus in-process sampling is usually enough.
What should a report include?
Part number and revision, ballooned drawing, nominal and tolerance, actual measurements, instrument, inspector, date and a pass/fail summary.
Can a caliper prove ±0.002 mm?
No. A caliper at 0.01 mm resolution cannot prove a 0.002 mm tolerance. The report should show a micrometer, pin gauge or CMM for critical features.
What if a characteristic is out?
The supplier should stop the run, correct the process and re-measure. The report should show the re-check, not a cleaned-up number.
Do you charge for an FAI?
The first article is part of the first order. If you need a full ballooned report on every characteristic, tell us at the quote stage so it is planned and priced.