First Article Inspection and Its Record

A first article is the first board of a run inspected completely, and its purpose is to confirm that the process, the documentation and the design agree. It is the cheapest point at which a setup error can be found, and it is only useful if it is complete.

What the First Article Confirms

It confirms that the correct program, stencil, paste and profile are in use, that the placement and the polarity are correct, and that the joints meet the criteria. Each of those is a separate check and each can fail on its own.

The inspection is against the drawing rather than against the previous board, which is the difference between a first article and a routine check. Our board quality notes describe the standard that is applied.

How Complete It Has to Be

A first article covers every placement, every polarity and a sample of the joints, plus the measurements the drawing names. A spot check of a few placements is a verification of the machine and not of the setup.

The difference matters because the errors it catches are systematic. A library rotation is wrong on every board, so a spot check that happens to look at a correct part misses it. Our placement capability notes describe how the machine reproduces the position.

The record is the board identification, the program and revision, the stencil identification, the paste lot, the profile, the measurements and the result. With those, a later failure can be compared with the board that was approved.

A record that names the program and not the revision is a record that cannot be compared after a change. The revision is the part that matters.

The approval is given by a named person against defined criteria rather than by the operator who ran the setup. That separation is what makes the approval a check rather than a formality.

Where the first article fails, the correction is made and a new first article is inspected rather than the same board being re-examined. A board that has been corrected is not a first article.

The approved first article is kept with the batch or in a defined place for the life of the run. It is the physical reference that a later question can be compared against.

A photograph is a useful addition and it does not replace the board. A photograph does not show a fillet height or a wetting angle reliably.

A change to the program, the stencil, the paste or the profile is a change to the process and requires a new first article. That includes a change made to correct a defect, because a correction is a change.

The rule is simple and it is frequently relaxed under time pressure, which is the situation in which the rule earns its place. Our first pass yield notes describe how a relaxed rule appears in the data.

Acceptance and Its Evidence

The sequence of operations is part of the specification, because a different order produces a different result from the same steps. Where the process window is narrow, the measurement resolution has to be better than the window, or the data cannot distinguish a good part from a marginal one.

Where two operations share a tolerance, the allocation between them should be explicit rather than left to whichever is measured first. The narrowest feature on the board usually sets the process window for the whole product, so it deserves the closest attention at review.

Where a requirement can be measured, it should be measured at the point of manufacture and recorded against the board or the lot it applies to. Sampling is a compromise between cost and confidence, and the sample size should follow from the failure rate that has to be detected.

Where a decision is made by judgement, a boundary sample makes the judgement repeatable between operators and between shifts. Where a process is at the edge of its capability, the margin should be bought deliberately rather than discovered during production.

A record that identifies the operator, the date and the settings is worth more than a record that identifies only the result. A measurement taken at the wrong point of the process describes the wrong thing, however carefully it is made.

Checks Before Release

Where the supplier and the user both measure the same property, they should agree on the method before the first delivery. The first article confirms that the setup matches the intent, and it is the cheapest point at which a wrong setup can still be corrected.

Documentation exists so that a person who was not present can reproduce the work and reach the same conclusion. The environment around the process, including temperature, humidity and cleanliness, sets limits on what the process can hold.

A parameter that is set once and never re verified drifts, and the drift is usually discovered by a defect rather than by the record.

Verification and Records

A result that cannot be reproduced is not a result, and reproducibility should be demonstrated rather than assumed. The acceptance criteria should be written before the work starts, so that the decision is made by the specification rather than by the person inspecting.

Is a first article needed for every batch? It is needed after every changeover and every process change, and a continuous run is covered by periodic checks.

Can the first article be inspected by the person who set up the line? It can, and the approval is stronger where a second person inspects it.

What does gopcba provide for first articles? We provide a complete inspection against the drawing rather than against the previous board, a record naming the program, the stencil, the paste lot and the profile revision, approval by a named person against defined criteria, the board retained as a physical reference, and a new first article after every change.

Points to Confirm at First Article

The checks that matter are the ones performed on the product rather than on a sample kept for the purpose, because a coupon that travels with the panel is the only evidence about that panel. The tooling, the material and the profile form one system, and a change to any of them should be assessed against the other two before it is released.

Where an operation cannot be verified afterwards, it has to be controlled during the operation, and that control has to be visible in the record.