PPAP and FAI for Stamped Parts: Documents a Factory Should Send
Short answer: PPAP is the full proof package that a production process can hold the drawing, and FAI is the proof that one specific part was measured against it. For a stamped part, the documents a factory should send are the same ones you should demand: a first-article dimensional report on real parts, material certificates, a process flow and control plan, capability data on critical dimensions, and the die and tooling record. No factory should ask you to approve a stamping without them.
Buying stamped parts without PPAP-style documentation is buying on trust, and trust is not a quality system. The good news: for a stamped part the documentation burden is manageable, and most of it is produced anyway by any factory with ISO9001 discipline. The skill is knowing which documents matter, what to check in each, and how to tell a real report from a decorated spreadsheet.
FAI vs PPAP: Two Different Proofs
First Article Inspection answers one question: does this specific part, from this specific tool, meet the drawing? A complete FAI measures every dimension on the drawing, records the results against the tolerance, and notes the tooling and material used. PPAP answers the bigger question: can the process repeat that part across a production run? PPAP bundles the FAI with process documentation, capability studies and control plans.
| Document | Question it answers | Typical timing |
|---|---|---|
| FAI / dimensional report | Does this part meet the drawing? | On the first production sample |
| Material certificate (MTR) | Is the material the specified grade? | With every material lot |
| Process flow | How is the part made, step by step? | Before production approval |
| Control plan | What is checked, when, and by whom? | With the process flow |
| Capability study (Cp/Cpk) | Can the process hold the tolerance? | After initial production run |
| Die/tooling record | What tool made it and what state is it in? | At tool approval |
Takeaway: FAI is a snapshot; PPAP is a movie. If you are approving a new stamping die, you need both — the FAI proves the die makes a correct part, and the PPAP documents prove it can keep making them.
The 18 PPAP Elements, Trimmed to What Matters
Automotive PPAP (AIAG) lists 18 elements, from design records to appearance approval to part submission warrant. A stamped part does not need all 18 at equal depth, and most stamping suppliers will submit what their customer's system demands. But five elements carry nearly all the engineering value, and a buyer who checks those five has covered the risk.
| Element | What to check | Red flag |
|---|---|---|
| Dimensional results (FAI) | Every dimension measured, gage listed | Only "critical" dims reported |
| Material certs | Grade, lot, mill, chemistry | Cert for a different grade |
| Process flow | Real sequence matches the die | Vague "stamping + ship" |
| Control plan | Checks match drawing risk | No burr or plating checks |
| Capability data | Cpk ≥ 1.33 typical on critical dims | No data, or only on easy dims |
| Part submission warrant | Signed, with disposition stated | No sign-off authority named |
Takeaway: a stamping FAI that reports ten dimensions when the drawing has forty is not an FAI — it is a selection. Demand full dimensional coverage on the first article, and treat a partial report as the first sign the factory's quality system runs on goodwill rather than procedure.
What a Proper FAI for a Stamped Part Contains
A serious first-article report for stamping lists the drawing revision, the die number, the material lot, the press and date, the gage used for each dimension, and the measured value next to the tolerance. It covers holes, profiles, bend angles, flatness, burr height and plating thickness — not just the length and width. Burr and edge condition matter on stamped parts precisely because they are stamping-specific failure modes that a machined part never has.
| Stamping characteristic | Typical check | Typical gage |
|---|---|---|
| Hole position and diameter | True position, size | Projector, pin gage, CMM |
| Profile and blank outline | Contour vs CAD | Profile projector, optical |
| Bend angles | Angle at rest | Angle gage, CMM |
| Flatness / twist | Deviation from datum | Surface plate, CMM |
| Burr height | Edge condition | Microscope, comparator |
| Plating thickness | µm on functional zones | X-ray fluorescence |
| Material | Grade and temper | MTR, hardness spot check |
Takeaway: the FAI document should read like a full audit of the part, not a courtesy letter. When a factory sends a dimensional report covering all characteristics with the gage type stated, it is telling you it measured the part; when it sends a one-line "all dims OK," it is telling you it did not.
Capability Data: The Part That Repeats
A single FAI proves the die can make one good part. Process capability — Cp and Cpk — proves the process can stay inside tolerance across a run. For stamped parts the critical dimensions are the ones that affect function and assembly: hole positions that mate with pins, contact geometry that sets force, and profile edges that must not short. Industry expectation for a capable process is typically Cpk ≥ 1.33, with 1.67 for safety-critical features.
| Cpk value | What it means | Typical action |
|---|---|---|
| < 1.00 | Process out of tolerance statistically | Fix process before approval |
| 1.00–1.33 | Marginal | Tighten control, increase inspection |
| 1.33–1.67 | Capable (common requirement) | Normal control plan |
| > 1.67 | Strongly capable | Can relax some inspection |
Takeaway: capability studies are only meaningful on characteristics that vary — hole positions, angles, dimensions affected by tool wear. Report Cpk on the drawing's critical callouts, and do not be impressed by capability data on the part's overall length, which any process holds. If your part has tight contact or mating features, this is where the real approval decision happens.
How a Serious Stamping Factory Ships Quality
Documentation is not an extra service; it is the residue of a working quality system. At BQUQ, batches leave the stamping line with dimensional inspection reports under our ISO9001 system, material traceability back to the coil lot, and burr and appearance checks built into the control plan — which is exactly what a PPAP or FAI submission packages into formal form. When you request PPAP level 3 or an AS9102-style FAI on a stamped part, the factory's answer should be "here is the file," not "we can do that for an extra charge" — and the review checklist in this guide is the same one our own quality engineers run before a submission ships.
Email sc@bquq.com or WhatsApp +86 137 1315 7787 with your PDF/DXF/STEP file. An engineer reviews it and replies with price, lead time and DFM notes on working days.
Frequently Asked Questions
Q: Is FAI the same as PPAP?
No. FAI (first article inspection) proves one sample part meets the drawing dimension by dimension. PPAP is the broader package — FAI plus material certs, process flow, control plan and capability data — proving the production process can repeat that result.
Q: What is PPAP level 3 and do I need it for stamped parts?
Level 3 is the default automotive submission level requiring the full element set: dimensional results, material certs, process documents, capability data and the warrant. Tier suppliers usually demand it; if your customer does not, a dimensional FAI plus material certs covers most risk.
Q: Why do stamped part FAIs include burr checks?
Burr is a stamping-specific defect that affects function — it can short adjacent terminals, cut wire insulation or jam assembly. A machined part has no equivalent, so FAI for stamping must verify edge condition, not just dimensions.
Q: What Cpk should a stamped critical dimension have?
A Cpk of at least 1.33 on critical dimensions is the common industry bar, with 1.67 for safety-related features. Capability must be studied on dimensions that actually vary with die wear and material, not on easy-to-hold overall sizes.
Q: How long does a full PPAP submission take from a stamping factory?
Plan on the FAI being ready with the first production samples, and the capability and process documents following after a short initial run — typically 1–3 weeks total once the die is approved. A factory quoting PPAP "same day as samples" is likely reusing template data.
Authored by the BQUQ Engineering Team. BQUQ is an ISO9001-certified source factory in Dongguan, China, running CNC machining, metal stamping, custom springs, heat sink and collet lines under one roof. Send drawings to sc@bquq.com or WhatsApp +86 13713157787 for a quote within 12 working hours. www.bquq.com
