First Article Inspection: How to Validate Your First Production Run
FAI is your last gate before full production volume. Here's how to structure a first article inspection that actually catches problems — before 10,000 units are built wrong.
First Article Inspection (FAI) is the formal process of verifying that the first units produced by a manufacturing process conform to all design requirements before full-volume production begins. It's your last opportunity to catch systematic problems — design issues, manufacturing process deviations, or specification mismatches — before they're replicated across thousands of units.
Done well, FAI gives you documented evidence that your manufacturing process is capable of producing conforming product. Done poorly — or skipped entirely — it leaves you exposed to field quality problems that trace back to the very first production run and were present in every single unit shipped.
What FAI Is Not
FAI is not the same as incoming inspection, lot acceptance testing, or production testing. It's a one-time validation of the manufacturing process and product configuration, conducted on the first units produced under production conditions. It should cover dimensional verification, materials verification, functional testing, cosmetic inspection, and documentation review — all against the released design requirements.
The FAI Process
Define the FAI Plan Before Production Starts
An FAI plan defines what will be inspected, what the acceptance criteria are, how many units will be inspected, and who is responsible for each inspection element. It must be written before production begins — not improvised after the first units come off the line. The plan should reference the released design documentation: drawings, BOM, test specification, and any applicable industry standards (IPC-A-610 for solder quality, for example).
Dimensional and Materials Verification
Verify that the physical product matches the design documentation. Check board dimensions and mounting hole positions against the drawing. Verify that the correct components are installed — compare component marking codes against the BOM. Check solder joint quality against IPC-A-610 acceptance criteria. Inspect cosmetic requirements — silkscreen legibility, conformal coating coverage, labeling. This is methodical, documentation-driven work. Have someone check against the actual drawing, not from memory.
Functional Testing to the Test Specification
Run every test in your test specification on the first article units. Document the results — not just pass/fail, but the actual measured values. This measured data becomes your production baseline. If a future production lot fails functional testing in a way that's subtle — marginal values rather than obvious failures — having baseline measurements from FAI gives you the data to identify when and how the process drifted. Pass/fail records without measured values are nearly useless for this purpose.
Documentation Review and Sign-Off
Verify that all manufacturing documentation — assembly drawing, test specification, work instructions — is current, released, and what was actually used to build the first articles. Any discrepancy between the documentation used to build and the released documentation is a non-conformance that must be resolved before production release. Confirm that your CM has a documented process for maintaining configuration control — using the right revision of the right documents for every production run.
"FAI is not a bureaucratic exercise. It's the point at which you formally verify that what you designed is what was built. Every subsequent production unit will be built the same way — make sure that way is right."
When FAI Finds a Problem
FAI findings fall into two categories: conformance issues (the product doesn't match the design) and design issues (the product matches the design but the design needs to change). Conformance issues are resolved by correcting the manufacturing process. Design issues require a design change — which means a new revision and, potentially, a new FAI on the revised product.
The economics of finding a design issue at FAI versus finding it in the field are stark. A design change discovered at FAI adds days to weeks to the schedule. The same issue discovered after 5,000 units are shipped and in customers' hands adds months — and a recall.
HarQuinn Tech supports FAI planning and execution as part of our manufacturing services. If you're heading toward first production and want help structuring your FAI plan, get in touch.
Preparing for Your First Production Run?
We support FAI planning, execution, and production readiness reviews for hardware programs heading to the factory floor.