IllustrationFirst article inspection (FAI) is a full check of the first units from a new mold, line or supplier against the drawings, BOM and specs, before the run continues. On an electronic device it covers dimensions, cosmetics, function and labels, and it runs again in part or in full when tooling, design, material or site changes.
The first units off a new tool or line show whether the factory can build what you approved. This guide covers what an FAI should check on a connected device, how it relates to T1 mold samples and the golden sample, what the FAI report should contain, and which changes call for a new one. Sourced statements link to the manufacturer, standards body or regulator that published them, as of November 2026.
This is an engineering summary. Agree your FAI scope with the factory in writing before the first run.
What is a first article inspection for an electronic device?
A first article inspection is a documented check of the first units made with production tooling, materials and processes. Protolabs' quality managers describe FAI as an inspection done with calibrated or certified measuring equipment, on parts taken at random from the beginning of a production run (Protolabs, April 2025, as of November 2026). On its molding service, Protolabs runs a partial FAI on samples of the first parts off the tool after the molding process is established (Protolabs inspections page, as of November 2026).
For a device, the first article is a finished unit: housing parts from each tool, an assembled board, a battery, labels and a packed box. Each can be wrong in its own way, so the FAI covers all of them. The aim is to find a wrong dimension, a reversed part or a missing label on a few units, before the error is built into the whole lot.
An FAI does not show how stable the process is over a long run. Protolabs separates the two: its capability study measures at least 30 evenly spread samples while the order runs and reports a Cpk value for critical dimensions (Protolabs, as of November 2026). Ongoing lot checks are a different step; see AQL sampling for electronics.
How does FAI relate to the golden sample and T1 mold samples?
These terms get mixed up in factory email. Each marks a different point on the way to production.
| Step | What it is | What it shows | Outcome |
|---|---|---|---|
| T1 mold samples | The first shots from a new tool. | Dimension errors, short shots, sink, flash. The tool will still change. | Steel adjustments, then the next trial. |
| Golden sample | An approved unit both sides sign as the reference. | What good looks like: color, gloss, texture, fit, button feel. | The comparison for every later build. |
| First article inspection | The first units built with the production tool, material, line and fixtures. | Every drawing characteristic, cosmetics, function, labels and packaging, recorded per unit. | Accept, accept with a recorded deviation, or reject. |
| Lot sampling | Units drawn from each lot after the first article passes. | A planned sample of the same checks. | Lot accepted or held. |
T1 samples are for tuning the tool
T1 parts come from the first trial of a new mold. Expect the toolmaker to adjust steel and settings after it, and often to run more trials. Measure T1 parts and send the results back, but do not sign them off as the first article. The process is not yet fixed. For how tools are built and changed, see injection mold tooling explained.
The golden sample is the reference you keep
A golden sample is a unit both sides approve as correct. It settles what a drawing cannot, such as color, gloss and how a button should feel. Keep two, one at the factory and one with you, signed and dated. Replace them when an approved change alters the look or feel. Limit samples next to it show the worst sink mark or scratch you will still accept.
What does a first article inspection check on a device?
List every check and its reference document before the first unit is built.
| Area | What to check | Reference | Typical tools |
|---|---|---|---|
| Plastic and metal parts | Every dimension on the drawing, critical ones first. Fit of mating parts, wall thickness at bosses, parting line and gate position. | Ballooned 2D drawing with tolerances. | Calipers, pin and height gauges, a CMM for GD&T callouts. |
| Cosmetics | Color, gloss, texture, sink, flow lines, weld lines, scratches. Inspect under set lighting at a set viewing distance. | Cosmetic spec and the golden sample. | Light booth, color reference, limit samples. |
| Circuit board assembly | Correct parts and values, polarity, solder joints, no bridges or missing parts, correct firmware loaded. | BOM, assembly drawing, the IPC-A-610 class named in your contract. | Microscope, AOI and X-ray images where the line has them. |
| Function | Power on, charging, battery current, radio link, sensors, microphones and speaker, buttons, LEDs. | Test specification with pass limits written in advance. | The production test fixture and its logged results per serial number. |
| Final assembly | Gaps and steps, screw torque, seal seating, battery fit, no pinched flex cables. | Assembly drawing and work instructions. | Feeler gauges, torque driver, one teardown. |
| Labels and markings | FCC ID text and position, model and serial number, regulatory text, permanence of the label. | Label drawing approved before the run. | Visual check, rub or adhesion check, barcode scan. |
| Packaging | Box, inserts, printed matter, accessories, carton markings. | Packaging BOM and artwork. | Visual check. |
Dimensions and the drawing
A dimensional FAI needs a drawing with tolerances. Xometry, for example, says a customer-specified dimensional print is required for a first article inspection, and that a part with GD&T requirements, other than an additively manufactured part, must be inspected on a coordinate measuring machine (Xometry inspection options, as of November 2026). Number each characteristic on the drawing with a balloon so every measured value maps to one feature. Inspect each cavity of a multi-cavity tool, since cavities can differ.
Boards, function and labels
For board workmanship, name the acceptance standard and class in the contract. IPC describes IPC-A-610J as a post-assembly acceptance standard, announced with J-STD-001J on April 8, 2024 (IPC news release, as of November 2026). We quote no criteria from it here because the standard is sold. Run the function test on the production fixture, the one the line will use.
Labels matter for an FCC-authorized device. Under 47 CFR 2.925, the FCC ID label must be permanently affixed and its data visible from outside the enclosure. When a device is too small to carry the FCC ID in four-point type or larger and has no display that can show electronic labeling, the FCC ID goes in the user manual and also on the packaging or a removable label (47 CFR 2.925, as of November 2026). Check the printed label against that rule and your approved artwork at FAI.
What goes in an FAI report?
The FAI report is the written record that the first units matched the documents. Aerospace suppliers use the SAE AS9102 format, and some contract manufacturers offer it on request. A consumer or wellness device rarely needs that format, but the same idea works: trace every requirement to a recorded result.
| Section | What it records |
|---|---|
| Identification | Part or product number, drawing revision, BOM revision, supplier, purchase order, inspection date, inspector, serial numbers of the units checked. |
| Characteristic results | One line per balloon on the drawing: nominal, tolerance, measured value, pass or fail, and the gauge used. |
| Materials and parts | Resin grade and lot, colorant, battery model, and any part that differs from the approved BOM. |
| Process record | Tool and cavity number, molding settings or a reference to them, assembly line, fixture version, firmware image and checksum. |
| Function results | The test log for each serial number, with the limits that applied. |
| Cosmetic and label results | Photos of each face next to the golden sample, and label photos. |
| Nonconformances | Each failure, its cause, the fix, and the re-check result. |
| Decision and sign-off | Accept, accept with a recorded deviation, or reject. Signed by the supplier and by you. |
Ask for the raw files with the report: CMM output, fixture logs and photos. A page that says pass on every line cannot be checked. Also agree whether the line waits for your sign-off. Xometry's default on its AS9102 option is to build the full lot and do the FAI at final QC, and a buyer who wants one part and a stop for approval chooses a custom inspection (Xometry, as of November 2026). Decide which model you want before the purchase order goes out.
When should you repeat a first article inspection?
An FAI is valid for the setup it checked. When the setup changes, part or all of it runs again. Write the triggers into the quality agreement.
| Change | What to re-inspect | Note |
|---|---|---|
| New tool, new cavity, or tool repair | Dimensions and cosmetics of the parts from that tool or cavity. | A repaired tool can shift a dimension that passed before. |
| Design change through an ECO | The changed features, plus anything they touch. | A partial FAI can cover only the change, so write its scope into the change order. |
| Change to the radio circuitry | The changed board, function and RF checks, and a review of the FCC grant. | On a device with an FCC grant of certification, 47 CFR 2.1043 requires a new grant for changes to frequency-determining circuitry, the basic modulator or maximum power, except as provided in 2.1043(b)(3) (as of November 2026). |
| New resin, colorant or part source | Fit, cosmetics, and any test the material affects. | Includes an alternate part added to the BOM. |
| New line or new factory | A full first article. | Fixtures, people and incoming parts all change at once. |
| New production firmware image | Function test and the firmware checksum on the line. | Under 2.1043, software changes that do not affect RF emissions need no extra FCC filing (as of November 2026). |
| Label or packaging artwork change | Labels and packaging only. | Check the FCC ID text again. |
| Restart after a long pause | The scope set in your quality agreement. | Agree the pause length that triggers it in advance. |
47 CFR 2.1043 requires a new grant of certification for some radio changes (as of November 2026). After a board change, use the FAI to confirm the radio parts and layout still match the certified build. Which radio changes are permissive, and who may make them, is covered with the change process in engineering change orders.
What should you ask your hardware team before the first article?
Bring this list to the pre-production review.
- Which drawing revision and BOM revision will the first article be checked against?
- Are all critical dimensions ballooned and marked, and who measures them?
- Will the line stop and wait for our approval, or keep building while the report is written?
- Which IPC-A-610 class applies to the boards?
- Does the function test log each serial number, and do we get the raw file?
- Which changes trigger a new or a delta first article, and is that list in the quality agreement?
For where incoming, in-line and final checks sit in our gated process, see quality checks from parts to packing.
Questions about first article inspection
What is the difference between a first article inspection and a golden sample?
The golden sample is the approved reference unit. The first article inspection checks the first production units against the drawings, the specs and that reference.
How many units should a first article inspection cover?
The sources we read set no number for consumer electronics. As one example, Protolabs says its partial FAI on molded parts allows measuring up to 10 parts and 25 dimensions (Protolabs, as of November 2026). Cover every cavity of each tool and more than one assembled unit, and write the count into the quality plan.
Do I need an AS9102 FAI report for a consumer device?
AS9102 is the aerospace format. A supplier may offer it: Xometry lists an FAI per SAE AS9102 and requires a dimensional print from the customer (Xometry, as of November 2026). A consumer device can use the simpler sections in the table above, unless your contract names a format.
What happens when the first article fails?
The run stays on hold. The supplier finds the cause, fixes it and builds new units, and the failed checks run again. A failure you choose to accept goes in the report as a signed deviation.
How can Duobay help with first article inspection?
Duobay develops custom devices with a Shenzhen engineering team: electronics, firmware, enclosure and app, through samples and small batches of 10–1,000 units. Source files are assigned to you at every paid gate. We do not publish prices, and initial calls are free. Tell us about your device.
If you want a first article plan for the first build of your device, tell us about your device.
Sources. All pages accessed November 6, 2026. The eCFR text was checked against the Cornell LII copy because ecfr.gov could not be fetched that day. Supplier offers and rules change, so confirm current terms before you rely on them.
- Protolabs blog, First Article Inspection, by Perry Haislet and Jimmy Spaight (April 11, 2025) (link)
- Protolabs, injection molding inspections (link)
- Xometry, Inspection Options (link)
- IPC, IPC Releases J Revisions to Two Leading Standards for Electronics Assembly (April 8, 2024) (link)
- eCFR, 47 CFR 2.925, Identification of equipment (link)
- eCFR, 47 CFR 2.1043, Changes in certificated equipment (link)
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