First Article Inspection specifications: what the numbers mean
First Article Inspection is a full dimensional check of the first part from a new setup, reported against the drawing. It is used for proving that the process can make the part before the batch is committed. This entry explains what it is, what the numbers on a data sheet mean, and what to put on a drawing.
It is written from the point of view of the buyer and the drawing office: the values that are realistic in production, the ones that cost money, and the way the result is verified. Where an industry sets the requirement, automotive is used as the example: a fixed takt, because a late delivery stops the line.
What the numbers mean
A data sheet for First Article Inspection is only useful if the numbers are read against the job. The usual entries, and what they tell you, are these.
- Standard – AS9102 for aerospace, or a customer format.
- Content – every dimension on the drawing, with a measured value.
- Equipment – calibrated, with the uncertainty recorded.
- Timing – before the batch starts, not after.
- Outcome – approval, or a corrective action.
- Retention – kept with the job record.
Comparing offers
Two suppliers can quote the same standard and mean different things, because the figures are often quoted under the most favourable conditions. Ask what the value is measured over, what the material was, and whether it is a typical or a guaranteed figure.
| Specification | Typical value |
|---|---|
| Standard | AS9102 for aerospace, or a customer format |
| Content | every dimension on the drawing, with a measured value |
| Equipment | calibrated, with the uncertainty recorded |
| Timing | before the batch starts, not after |
| Outcome | approval, or a corrective action |
| Retention | kept with the job record |
What to check before specifying
Make sure the value you need is the value you have called up. Say on the drawing which standard the report has to follow, and the difference between a typical and a worst case figure is where most disputes start.
Applications
First Article Inspection is used for proving that the process can make the part before the batch is committed, and in practice it appears most often in aerospace, medical, automotive launch, any new part number.
How it fits into a machining route
First Article Inspection applies to the whole drawing rather than to one operation. It sets how the part is measured as much as how it is made, which is why it belongs on the drawing from the first issue and not in a note added after a query.The route is fixed before the first part is cut, and it is the route rather than the individual setting that holds the result: the inspection time, which is small next to a scrapped batch. Where a drawing calls for something the route cannot hold economically, that is raised at quotation rather than after the parts are made.
Standards, documentation and what is issued
The documentation requirement is AS9102 or the customer's own format. Material is supplied against a certificate where the application calls for it, inspection results are recorded with the job, and the records are kept so that a repeat order can be compared with the first instead of being measured from scratch.
Every drawing feature, on calibrated equipment is the verification step. Where a customer format or a standard report is required, it is agreed before the batch starts, because a report written after the event is a report nobody can use.
Frequently asked questions
What tolerance should be specified for First Article Inspection?
measured, not assumed is realistic in production. Tightening it beyond the functional requirement increases cost without improving the part.
Which material is usually used?
any is the usual choice, supplied against AS9102 or the customer's own format.
How is the result verified?
Every drawing feature, on calibrated equipment, with the results recorded so a repeat order can be compared with the first.
What is the most common mistake?
Measuring a part that is still warm from the machine.
How long does it take and what does it cost?
A realistic cycle is 1 to 3 hours for a complex part, and the cost driver is the inspection time, which is small next to a scrapped batch.
Related capability
If you are specifying First Article Inspection on a drawing and want a second opinion on the route, send the model and the quantity. The first response is a manufacturability review with the likely risk points and a quotation, so the decision can be made on facts rather than on a price alone.
Machining, inspection and documentation are handled in one place, which is why the dimensional report and the material certificate arrive with the parts rather than after them.
Related entries
These entries sit next to First Article Inspection in the encyclopedia: ISO 2768 General Tolerances, EN 10204 Material Certificates, CNC Milling. Reading them together gives a fuller picture of how the process, the material and the measurement affect each other.
