A first article inspection is a full dimensional check of the first part off a new setup, compared against the drawing. Done properly, it catches misreadings before they become a container of scrap.
What a useful FAI report contains
Every dimension on the drawing, numbered and traceable. The drawing is ballooned, each balloon has a measured value, and the two can be matched without guesswork.
The measured value, not a pass/fail tick. "In tolerance" tells you nothing about where in the band the process is sitting. A dimension consistently near the upper limit is a warning about the next batch, even though this batch passed.
The instrument used for each measurement. A bore measured with a caliper and a bore measured on a CMM are not the same claim.
Material certification. Traceable to the mill, matching the alloy on the drawing.
Photographs of the actual part. Useful for finish and appearance items that no number captures.
How to read it
Look for dimensions sitting close to a limit. A part that passes with every value near nominal reflects a process that is centred. A part that passes with several values within a few microns of the limit reflects a process that will produce rejects at volume, even though this part is good.
Look for dimensions reported as nominal exactly. Real measurements rarely land exactly on nominal across many features. A column of perfectly nominal values usually means the drawing was transcribed rather than the part measured.
Check that difficult features were actually measured. Deep bores, internal threads and true position callouts are the ones most likely to be quietly skipped.
Say what you want before the order runs
The most common failure is asking for an FAI after the parts are made. By then the setup has been broken down and re-measuring costs real time.
Agree in writing, before production: which dimensions are critical, that a full ballooned report is required, what happens if a value falls outside the drawing, and whether shipment is held pending your approval of the report.
For repeat orders
A full FAI on every repeat batch is usually unnecessary and adds cost. A reasonable middle ground is a full FAI on the first batch and on any batch after a process or material change, with a reduced report on critical dimensions in between. Agree what triggers a fresh full FAI — new material lot, new fixture, gap of more than a certain number of months.
The short version
Specify the report before you order, insist on measured values rather than ticks, and read it for how close the process is to the edge — not just whether it passed.
