First Article Inspection for Metal Parts: A Buyer’s Guide

A sample proves that the design fits. A first article inspection (FAI) proves that the production process holds the drawing — every dimension measured, every requirement verified, with records that stand up to an audit. For a buyer, that difference carries the entire case: the FAI separates “this one part is good” from “the next ten thousand will be good.” This guide explains when a first article inspection applies, what a complete one contains, which records to request, and how to specify the whole thing on a purchase order.

When an FAI Applies

First, the trigger list. In practice, an FAI is standard whenever one of the following is true:

• a new part enters production;
• a process changes — new die, new machine, new weld procedure;
• production has paused for a long period and the line restarts;
• the supplier or material source changes;
• the customer program requires it — automotive programs formalize this as PPAP.

So each trigger resets the assumption that the process is stable. In other words, the FAI is not a one-time luxury; it is the price of confidence for the entire run that follows.

What a Complete First Article Inspection Contains

Second, know what you are buying. A complete first article inspection reports on every characteristic on the drawing, in four groups.

• Dimensions. Every linear, angular, and geometric feature measures against its tolerance. Critical dimensions report the actual value, not just a pass flag.
• Material. The grade verifies against the specification, with the certificate attached.
• Finish and function. Coating coverage and appearance check out; threads engage; the part assembles against its mating component.
• Process records. The weld procedures, heat numbers, and machine and tooling identifiers all appear.

Typically, the two standard reporting formats are AS9102 (the aerospace-style form, the most structured) and ISO 10045 (the international equivalent). Accept either one when it fills completely — ISO publishes the 10045 scope.

The Inspection Records Buyers Should Know

Next, the table below maps each record to what it proves and when you should require it.

Because each record costs money and time, specify the set deliberately. A 3.1 certificate on a painted mild-steel bracket is paper you will never use. A CMM report on a mating flange is the difference between a fit and a rework. Our ISO 9001 guide explains which records a certified shop keeps under clauses 8.5.2 and 8.6.

In-Process vs. Final Inspection

In practice, a single end-of-line check does not form a control plan. Instead, the working structure has three layers. First-off checks: the operator and inspector verify the first part from a new setup before the run continues. In-process checks: sampling at intervals through the run — dimensional spot checks, weld appearance, coating cure. Final inspection: the release check against the drawing before packaging. Finally, ask a supplier how each layer staffs and documents — the answer says more about their system than any certificate on the wall.

How to Specify a First Article Inspection on the PO

Because ambiguity travels to the invoice, write the requirement in one sentence per item. A working template:

• “First article inspection per AS9102 (or ISO 10045) at first production, with CMM report for dimensions marked CRIT.”
• “Material certificate EN 10204 type 3.1 per heat number, all batches.”
• “PMI verification on the first batch for alloy 304.”
• “FAI re-run after any die change, material source change, or interruption over 6 months.”

Put these lines in the quality clause of the PO. Also, mirror them in the RFQ (item 7 of our RFQ checklist). The supplier who accepts them on paper keeps the records under pressure.

When a Part Fails: the Corrective Path

Finally, know what happens after a failure, because the process matters as much as the prevention. The standard path runs containment first: sort and screen the affected lots, so no bad part ships. Then it runs root-cause analysis, and then corrective action with verification. That is the 8D structure you will see in a formal report. A supplier who produces that sequence from their own logs recovers a failure in days. Our ISO 9001 guide describes those nonconformance records under clause 10.2. One who cannot, recovers it in disputes.

Frequently Asked Questions

What separates a first article inspection from PPAP?

The FAI is the inspection event and its report. PPAP (Production Part Approval Process) is the automotive customer program. It wraps the FAI inside a larger approval package: process flow, control plan, capability studies (Cpk), material certificates. So specify PPAP when your customer is automotive; otherwise, FAI per AS9102 / ISO 10045 is the right level. AIAG maintains the PPAP reference.

Who pays for the FAI?

Usually the supplier absorbs a standard first article as the cost of doing business. A customer-specified FAI with CMM on every critical feature often appears as a one-time line. Either way, ask which is which in the quote — it is a legitimate line to compare across suppliers.

What is a CMM report, and how do I read it?

Typically, a CMM (coordinate measuring machine) report lists each measured feature with its nominal value, tolerance, actual value, and result. Read the actual values on the CRIT dimensions, not just the pass column. A part that passes but sits at the tolerance edge in the same direction every time tells you something. Your process center sits off.

When do I really need an EN 10204 3.1 certificate?

Require it when the material grade carries the function. That means stainless where your spec names the corrosion duty, or alloy steel where strength or heat treatment matters. It also covers any application with a contractual or regulatory paper trail. For painted mild-steel brackets, a 3.1 is usually overkill — a mill test reference suffices.

What is PMI, and when should I require it?

PMI (positive material identification) verifies the alloy on the actual part, non-destructively. So it catches the classic substitution: 201 in place of 304, or 6061 in place of 5052. Require it on the first batch of any program where a wrong alloy fails the application. Also, require it where the material comes from a third-party mill.

How long does a first article inspection take?

The inspection itself runs a day or two. The reporting and approval loop adds a few more days. The practical schedule effect stays small. A failure that appears in week six costs far more than an FAI in week one.