First Article Inspection for Stamped Parts: What to Check
Short answer: A first article inspection (FAI) for stamped parts should verify the full drawing — every dimension, tolerance, burr limit, material grade and finish — on parts taken from a production-intent die, not a prototype. Check the strip, the part, and the process: material certification, die setup, blank layout, bend angles, hole positions, burr height, flatness, plating thickness and a capability run of at least 30 consecutive parts. Sign off only when the FAI report matches the drawing, the sample is retained, and the die is locked to documented settings. Budget 12 working hours for the quotation stage and 3-10 working days for a full FAI package on a new progressive die.
First article inspection is the gate between "the die works" and "we can ship thousands of these." For stamped parts the stakes are higher than for many machined components, because a progressive die commits dozens of features to hardened steel at once. If a hole is 0.05 mm off, you are not adjusting a program — you are grinding a die insert.
This guide covers what a rigorous FAI for stamped metal parts actually contains, what to measure, what to document, and the failure modes that most often slip through a loose first article review.
What Is a First Article Inspection for Stamped Parts?
A first article inspection is a formal, documented verification that the first parts produced from a production tooling setup conform to all engineering requirements. For stamping, that means the die, the press, the coil, the lubricant and the operator setup are all at production intent — not a hand-built sample or a soft-tool prototype.
The FAI report is a record. It typically includes:
- The drawing revision and part number being verified
- A ballooned drawing with numbered characteristics
- Measured values for every ballooned dimension, with tolerance and pass/fail
- Material and finish certifications
- Visual and functional checks (burrs, cracks, coating, spring-back)
- The measurement equipment used, with calibration status
- A retained first article sample, signed and dated
For automotive, medical or aerospace supply chains, FAI usually feeds into a PPAP or similar submission. For industrial and consumer electronics buyers, a well-built FAI report is still the cheapest insurance you will ever buy: it catches a die problem while the die is still soft, still on the bench, and still cheap to fix.
FAI vs. PPAP vs. Layout Inspection
These terms get mixed up. FAI is the dimensional and visual verification of the first production parts. PPAP is a broader submission package that includes FAI plus process flow, PFMEA, control plan, capability studies and sample parts. A layout inspection is a full dimensional check of every drawing characteristic, which is essentially the dimensional core of an FAI. If your supplier says "we did a layout," ask whether it was on production tooling and whether the report is signed.
The Core FAI Checklist for Stamped Metal Parts
The table below is the working checklist we use for stamped parts at BQUQ. It is organized by what you are inspecting, not by department.
| Category | What to Check | Typical Acceptance Basis |
|---|---|---|
| Material | Grade, temper, thickness, coil width, mill cert | Per drawing; thickness within coil tolerance |
| Strip / blank | Blank size, nesting, burr direction, carrier width | Per strip layout; no edge cracks |
| Critical dimensions | Hole diameters, pitch, bend angles, overall length | Per drawing; 100% of ballooned dims measured |
| Profile / form | Flatness, twist, camber, bend radii, spring-back | Per drawing or agreed cosmetic standard |
| Burrs | Burr height at shear edges, directional burr side | Typically ≤ 0.05 mm unless otherwise specified |
| Surface | Scratches, die marks, galling, orange peel, dents | Per approved boundary sample |
| Coating / finish | Plating thickness, adhesion, solderability, color | Per spec; XRF or coulomb test data |
| Functional | Insertion force, contact resistance, fit in mating part | Per drawing or functional spec |
| Process | Die setup sheet, press tonnage, lubrication, stroke rate | Documented and locked |
| Documentation | Ballooned drawing, FAI report, certs, sample retention | Signed, dated, revision-controlled |
Two rows in that table deserve emphasis because they are the most commonly under-specified: burrs and flatness. Buyers often write "deburr" on a drawing without a number. That leaves the decision to the die builder and the inspector, and it will be interpreted differently on the next order.
Burr Specifications: Put a Number on the Drawing
Burr height is a function of die clearance, punch sharpness and material. A well-maintained progressive die running a reasonable clearance typically holds burr height under 0.05 mm on thin-gauge steel, but that is a typical figure, not a guarantee — it depends on material, thickness and how many strokes are on the tool.
Specify burr height as a maximum value, and specify which side the burr is allowed on. In many assemblies the burr direction matters more than the burr size, because a burr on the wrong face can interfere with a mating contact or scratch a coating on an adjacent part.
Flatness, Twist and Camber
Stamped parts are rarely perfectly flat. Coil has residual stress, and every shear and bend redistributes it. Define flatness as a measured value over a defined area, and define camber as deviation along the strip length. If your assembly is stack-sensitive — think shims, spacers, lead frames or contact springs — flatness is often the characteristic that actually drives your yield, not the hole diameter.
Which Dimensions Actually Matter Most?
Not all characteristics carry equal risk. A useful FAI prioritizes by function, not by drawing order. The table below shows how we typically classify stamped-part characteristics.
| Class | Definition | Examples | Inspection Level |
|---|---|---|---|
| Critical | Affects safety, fit or function; failure stops assembly | Mating hole pitch, contact geometry, terminal width | 100% measured, capability study |
| Major | Affects assembly or customer fit | Overall length, bend angle, burr height | Measured on FAI + periodic SPC |
| Minor | Cosmetic or non-functional | Surface die marks, logo position | Visual against boundary sample |
| Reference | Not inspected, informational | Theoretical bend allowance, blank weight | Not measured |
The practical point: a first article report that measures 40 minor dimensions and skips the two critical mating features is worse than useless — it creates false confidence. Push your supplier to identify critical-to-function characteristics before the die is cut, and make sure the FAI report measures those with the right instrument.
For a deeper look at how die construction choices affect which characteristics you can hold, see our article on progressive die strip layout.
What Should Be in the FAI Report Package?
A complete FAI package for a stamped part should arrive as a single, revision-controlled document set. Ask for:
1. Ballooned drawing — every characteristic numbered, matching the report line by line.
2. Dimensional results table — nominal, tolerance, actual, deviation, pass/fail.
3. Material certification — mill cert with heat number traceable to the coil used.
4. Finish certification — plating thickness readings, adhesion test results where applicable.
5. Visual inspection record — with a signed boundary sample or photo set.
6. Capability data — Cp/Cpk on critical characteristics from a run of consecutive parts.
7. Die setup record — press, tonnage, shut height, feed length, lubrication.
8. Retained sample — at least one first article part, labeled and stored.
If you are sourcing stamped terminals or contacts, the finish and functional rows carry extra weight. Plating thickness variation across a reel can change insertion force and contact resistance, so FAI should include readings from multiple locations on the strip, not one part from the middle. Our stamping terminals and contacts page covers how we structure that verification for connector and battery-contact parts.
How Many Parts Should You Measure?
A single part proves nothing about a process; it only proves that one part existed. For a meaningful FAI, measure a minimum of 30 consecutive parts from the same setup for critical characteristics, and at least 5-10 parts for the full ballooned dimension set. The 30-part run gives you a rough capability picture — enough to see whether the process is centered or drifting toward a tolerance limit.
For very high-volume programs, a longer run of 100 or more parts is reasonable on the two or three most critical characteristics. Note that a 30-piece study gives an indicative capability estimate, not a statistically robust Cpk; treat it as a screening tool.
Common Failure Modes an FAI Should Catch
A good FAI is designed around what actually goes wrong in stamping. The most frequent issues we see when reviewing incoming first articles:
- Die clearance too large — torn shear edges, excessive burr, poor edge finish.
- Die clearance too small — secondary shear, slivers, rapid punch wear.
- Insufficient hold-down or spring pressure — twist, camber, inconsistent bend angle.
- Spring-back not compensated — bend angles drifting out of tolerance on higher-strength material.
- Strip feed error — progressive pitch drift, causing cumulative hole position error.
- Pilot misalignment — off-center holes that pass FAI on one part but fail at reel ends.
- Galling — material pickup on the die face, visible as scratches that worsen over the run.
- Coil thickness variation — dimensions that pass at the start of the coil and fail at the end.
The last two are the reason FAI should sample across the coil, not from one convenient offcut. If your supplier only measures parts from the first few meters, you have not verified the process — you have verified the setup.
For a systematic approach to diagnosing these issues after production starts, see stamping die troubleshooting.
How BQUQ Runs First Article Inspection
BQUQ runs four production lines in one Dongguan factory under ISO9001: CNC machining to ±0.005 mm, metal stamping, custom springs and heat sink production. Because stamping, spring forming and machining sit under one roof, a stamped bracket that needs a tapped hole or a formed spring leg can be verified as a complete assembly rather than as a loose part — which is where most cross-process tolerance stack-ups hide.
Our FAI workflow for a new stamped part:
1. Drawing review — we flag missing burr, flatness and finish specifications before quoting.
2. DFM feedback — tolerance and feature recommendations, usually within the 12-working-hour quote window.
3. Die build and first-off — parts pulled from production-intent tooling.
4. Dimensional and visual FAI — ballooned drawing, measured results, retained sample.
5. Capability run — 30+ consecutive parts on critical characteristics.
6. Sign-off and release — locked setup sheet, revision-controlled report, flexible MOQ production.
For brackets and mounting hardware, the FAI usually hinges on hole position, flatness and burr direction — the three things that decide whether the part sits flush and assembles without rework. Details are on our stamping brackets and mounts page.
If you are comparing sourcing regions or need a broader view of what a China stamping program involves, our custom metal stamping guide walks through tooling, lead times and documentation expectations.
Frequently Asked Questions
Q: When should a first article inspection be performed?
A: FAI is performed after a new die is built, after any die repair or insert replacement that affects a drawing characteristic, after a tool transfer to a different press, and after any engineering change to the part or material. It is also standard at the start of a new production campaign if the tool has been idle for an extended period. The principle is simple: any change that could move a dimension requires re-verification before shipping.
Q: How many parts should be measured in a stamping FAI?
A: Measure the full ballooned dimension set on at least 5-10 parts, and run 30 or more consecutive parts for capability on critical characteristics. Sample across the coil rather than from one location, so thickness and temper variation are captured. A 30-piece study gives an indicative capability estimate rather than a statistically robust Cpk, so treat it as a screening tool and follow with ongoing SPC.
Q: What burr height is acceptable on stamped metal parts?
A: There is no universal number — it depends on material, thickness, function and the mating assembly. For thin-gauge steel and brass parts, a typical production target is burr height at or below 0.05 mm, but this must be written on the drawing as a maximum with the permitted burr side stated. If the drawing only says "deburr," expect inconsistent interpretation between suppliers and between production runs.
Q: Does FAI replace ongoing inspection?
A: No. FAI verifies that the process is capable at the start; it does not guarantee it stays capable. Stamping tools wear, punches chip and clearances open up over the run. FAI should be backed by a control plan with in-process checks, periodic dimensional sampling, and documented die maintenance intervals. For high-volume programs, add SPC on the critical characteristics identified during the FAI review.
Q: What is the difference between FAI and a layout inspection?
A: A layout inspection is the full dimensional measurement of every drawing characteristic. FAI is broader: it combines that dimensional verification with material and finish certification, visual and functional checks, process documentation, and a retained sample, all performed on production-intent tooling. In practice, the layout report often forms the dimensional section of the FAI package, and the two are submitted together.
Related Resources
- About BQUQ and our four Dongguan production lines: /about/
- Custom metal stamping capabilities and tooling: /custom-metal-stamping/
- Stamped terminals, contacts and precision electrical parts: /stamping-terminals-contacts/
- Stamped brackets, mounts and structural hardware: /stamping-brackets-mounts/
- Industry trends in metal manufacturing and sourcing: /industry-dynamics/
- Technical articles and engineering guides: /bquq-blog/
- Frequently asked questions on sourcing and quality: /faq/
- Contact our engineering team for a 12-hour quote: /contact/
Authored by the BQUQ Engineering Team. BQUQ (Dongguan) runs CNC machining (±0.005 mm), metal stamping, custom springs, and heat sink production in one ISO9001 factory. Source-direct from Dongguan, China — quote in 12 hours: sc@bquq.com | WhatsApp +86 13713157787 | www.bquq.com
