Inspection Reports, FAI and PPAP: What Ships With Your Parts
Dimensional report · EN 10204 3.1 · AS9102 FAI · PPAP level 3 · Cpk · RoHS / REACH
Every production lot from CHX Metal ships with a dimensional inspection report measured against a ballooned drawing, plus the mill's EN 10204 3.1 material certificate and a certificate of conformity. On request we build an AS9102 first article inspection, a PPAP level 3 package, SPC data with Cpk per critical feature, plating thickness records and RoHS/REACH declarations. What we do not do is issue a certificate we have not measured.
The difference between a supplier you keep and a supplier you audit is not the parts — it is whether the paperwork lets you prove the parts were right. A dimensional report with three measurements on a drawing with forty features is a decoration. This page sets out exactly what we issue, what each document is for, and where the gaps honestly are.
The document set, and what each one proves
| Document | What it proves | When it is issued | Standard |
|---|---|---|---|
| Certificate of conformity (CoC) | The lot was made to the drawing and the PO | Every lot | EN 10204 2.2 type statement |
| Dimensional inspection report | Which features were measured, and the result | Every lot | Ballooned drawing, ISO 14253 decision rules |
| Material certificate 3.1 | Chemistry and mechanicals of the actual melt | Every lot, from the mill | EN 10204 3.1 |
| First article inspection (FAI) | Every drawing feature was verified once, before production | First lot, and after any change | AS9102 (aerospace) or a full balloon report |
| PPAP level 3 | The process is understood and controlled, with evidence | New part or process change | AIAG PPAP 4th edition |
| SPC / Cpk report | The process is capable, not just the parts conforming | On request, per critical feature | AIAG SPC, Cpk targets 1.33 / 1.67 |
| Plating thickness record | The coating is the specified thickness on the functional area | Plated lots | XRF, ISO 3497 |
| Salt spray report | Corrosion performance of the finish | On request, per finish | ASTM B117 / ISO 9227 |
| RoHS / REACH declaration | Substance compliance of the delivered part | Per part number | EU 2011/65 and REACH SVHC list |
| Hardness / heat treat cert | The heat treatment actually applied | Heat treated lots | Partner certificate, traceable to lot |
A 3.1 certificate means the document is issued by an inspector independent of the manufacturing department. A 2.2 is a statement by the supplier. Buyers who require 3.1 should say so on the PO, because the mill charges for it.
A dimensional report that is worth reading
The report should be a copy of the customer's drawing with every toleranced feature ballooned and numbered, and a table listing the nominal, the tolerance, the measured value and the instrument. Two details tell you whether it is real:
- Are the measured values distributed? A report where every dimension sits at nominal is a report that was typed, not measured. Real parts scatter inside the band.
- Is the instrument named? “CMM” is not enough — the CMM's maximum permissible error and the measurement uncertainty have to be smaller than the tolerance being judged, and the report should show it.
Our reports list the instrument per feature (CMM, micrometer, pin gauge, optical comparator, roughness tester), the ambient temperature where it matters, and a pass/fail per feature against the drawing. Where a feature is at the edge of the tolerance band we mark it, because the buyer's incoming inspection will find it anyway and a surprise is worse than a note.
Cpk, and what a drawing should ask for
Conformance asks whether the parts are inside the limits. Capability asks whether the process will keep them there. A lot can be 100 % conforming with a Cpk of 0.8, and that lot will produce scrap within three tool changes.
| Cpk | What it means | Reject rate at the limit | Typical requirement |
|---|---|---|---|
| 1.00 | The process just fits the tolerance | ~0.27 % (2,700 ppm) | Minimum for non-critical dimensions |
| 1.33 | Standard industrial capability | ~63 ppm | The default target on a drawing for a critical feature |
| 1.67 | Comfortable margin, tool wear absorbed | ~0.6 ppm | Automotive and medical critical characteristics |
| 2.00 | Process centred with wide margin | ~0.002 ppm | Safety-critical, or where the feature cannot be gauged 100 % |
Calculated on a stable process with at least 25 subgroups. Where a feature cannot reach 1.33, our position is to say so at quotation and propose either 100 % inspection or a drawing change — not to report a number that cannot be reproduced.
FAI and PPAP: when they are needed and what they cost
First article inspection is a one-time proof that the process can make the part. AS9102 lays out three forms: the part number accountability, the product accountability with every characteristic measured, and the characteristic accountability that links each measurement to a drawing balloon. For non-aerospace customers we issue the same content as a full ballooned report, without the AS9102 form numbering, which is usually what a Tier-1 supplier actually wants to file.
PPAP level 3 is the automotive package: design records, engineering change documents, DFMEA and PFMEA, control plan, MSA study, dimensional results, material and performance test results, initial process study, and the PSW. Level 3 with a full dimensional and material package is what most OEMs require, and it takes 1–3 weeks to prepare properly for a complex part.
Cost, stated plainly: a dimensional report is included in the lot price. A full FAI is quoted as a separate line, typically a few hundred dollars for a part with 20–40 characteristics, because measuring every feature once properly takes hours. A PPAP level 3 is quoted per part number. Charging for it separately is honest — the alternative is to bury it and then deliver a thinner package than the customer assumed.
One honest limitation: IATF 16949 is in implementation, not yet certified, and AS9100 is not held. We can produce the FAI and PPAP evidence, and the plant runs to ISO 9001:2015 with a control plan; what we cannot do is issue a certificate we do not have. Aerospace and automotive buyers who need the certificate as a gate should know that before the RFQ.
Sampling, AQL, and 100 % inspection
Not every feature is worth measuring on every part, and pretending otherwise raises the price without lowering the risk. The default is ISO 2859-1, general inspection level II, AQL 1.0 for major characteristics and AQL 2.5 for minor, with a critical characteristic at AQL 0.1 or 100 % inspection.
Where 100 % inspection is genuinely justified — a safety feature, a fit that stops a line, a customer who has been burned before — the honest options are a dedicated gauge station, an optical sorting system, or a vision check in the cell. We quote it as an operation because it has a cycle time. A supplier who says “100 % inspected, no extra cost” is describing a glance, not an inspection.
Non-conformance: what happens when something is wrong
The measure of a quality system is not the absence of defects but the speed and honesty of the response. Our sequence:
- Containment within 24 hours — identify the affected lots by date code, tell the customer which shipments are in scope, and stop further shipments of the suspect configuration.
- Root cause with the actual mechanism, not “operator error”. If the cause is a fixture that was not rigid enough, the 8D says so.
- Corrective action that changes the process or the gauge, plus an inspection step that would catch a recurrence.
- Verification on the next three lots, with the data sent to the customer rather than kept internally.
Sorting and rework cost, and return freight on a rejected lot, are on us when the non-conformance is ours. That is stated in the quote terms rather than negotiated after the failure.
Related guides and capabilities
ISO certified CNC machining · Supplier profile · Tolerance capability · IP protection & NDA · How to choose a supplier · Machining capabilities
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Frequently asked questions
Do you charge for the inspection report?
No. A dimensional report against the ballooned drawing, the material certificate and the CoC are part of the lot price. A full first article inspection or a PPAP package is quoted separately because it is real engineering time.
Is the material certificate 3.1 or 2.2?
3.1 by default for metal parts — the certificate is issued by an inspector independent of the mill's manufacturing department, and the certificate number appears on our inspection report. State 2.2 on the PO only if you genuinely do not need the traceability; it is cheaper.
Can you provide Cpk on a specific feature?
Yes, with 25 or more subgroups from a stable run, and we will tell you when a feature cannot reach 1.33 instead of reporting an unreproducible number. Features that cannot be gauged in-process are measured offline and the capability is stated as an estimate.
Do you hold AS9100 or IATF 16949?
Neither, and we say so before the RFQ rather than after. The plant is ISO 9001:2015 certified, IATF 16949 is in implementation, and we produce AS9102-format first article content for customers who need the evidence without requiring the certificate.
What is your measurement uncertainty?
The CMM in climate-controlled conditions is used only where its maximum permissible error is comfortably inside the tolerance. For a ±0.005 mm feature the decision rule follows ISO 14253-1, and the report states the instrument so the buyer can apply the same rule on receipt.
Can you inspect to a customer's own control plan?
Yes. Send the control plan with the PO and we will map our in-process checks to it, including the sampling frequency and the reaction plan. Where our process cannot meet a specified frequency we will say so before accepting the order.
How long do you keep records?
Inspection reports, material certificates and lot traceability records are kept for five years, and longer for aerospace and medical programmes on request. Records are retrievable by lot number, which is why the lot label matters more than the carton label.
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Name, email and what you need. Attach a drawing if you have one — STEP, PDF, DXF or a photo of the print. We reply with unit price, MOQ and lead time, usually within one working day.
Prefer email? Send drawings to mc@chxmetal.com.