The paperwork that turns a first order into a programme
Shops tend to experience documentation as a tax imposed by fussy customers. From the buyer’s side it is the opposite: it is the main thing that distinguishes a supplier they can build a programme on from one they will use once.
The distinction matters commercially, because first orders are low margin and programmes are not.
What each document actually obliges you to do
Certificate of Conformance. You state in writing that the parts meet the drawing. Cheap, and it proves nothing about the metal.
EN 10204 Type 3.1 mill certificate. This is not yours to issue — it comes from the material producer, certifying the chemistry and mechanical properties of the specific heat, validated by the mill’s inspection department independently of production. Your obligation is to buy material that comes with one and keep it attached to the right parts.
That sounds trivial until you buy from a distributor who cannot supply the original certificate, or you cut two heats into one batch.
Heat-lot traceability. The finished part can be traced to its heat number. This requires, from the first cut:
- Material segregated physically by heat
- A record of which bar produced which parts
- Marking or bagging that survives to delivery
This cannot be reconstructed afterwards. Either you worked that way from the beginning or the documentation is a guess, and a certificate that does not genuinely tie to the parts is a far more serious problem than a late delivery. It is the one area where an honest “we did not segregate this batch” is enormously better than the alternative.
AS9102 First Article Inspection. A dimensional proof rather than a material one: every characteristic on the drawing ballooned, numbered and measured, across three forms covering part accountability, product accountability including material and special processes, and characteristic accountability.
It is a real piece of work the first time — commonly a day or more of engineering on a complex part — and small on repeat pieces.
What it costs you, honestly
| Requirement | What it demands of the shop |
|---|---|
| CoC only | A signature |
| 3.1 mill cert | Buying from sources that supply them, and filing |
| Heat-lot traceability | Segregation and records from the first cut |
| Dimensional report, marked characteristics | CMM time, a consistent report format |
| Full dimensional report, all features | Can rival the machining time on complex parts |
| AS9102 FAI | A day or more of engineering on the first article |
The expensive combination is a complex part with sixty characteristics measured 100 %. Price it as inspection work with machining attached, because that is what it is.
Quote it, do not absorb it
The failure that costs shops money is agreeing to documentation after the price is fixed. Two specific versions of this:
Accepting “aerospace quality” as a specification. It is not one. Ask what is actually required: certificate level, traceability, report scope, FAI or not. Asking that question at quote stage reads as competence, not as obstruction.
Adding traceability mid-job. Discussed above — you cannot. If a customer asks for it after the material has been cut, the honest answer is that it applies from the next batch.
The calibration file nobody asks about until they do
Inspection equipment that is not calibrated, with certificates traceable to a national standard, makes every report you issue arguable. It is cheap insurance and it is one of the first things a serious buyer or an auditor looks for.
Keep current certificates for the CMM, the hardness tester, the surface roughness tester and the gauges, and be able to produce them the same day they are requested. Being slow to produce a calibration certificate creates doubt out of proportion to the underlying issue.
Why this is worth building
A buyer placing an exotic alloy part is carrying risk they cannot easily inspect. Documentation is how they transfer part of that risk into something checkable.
Shops that make this easy get asked back, get the second part in the family, and eventually get treated as the default rather than as one of three quotes. Shops that make it difficult get used for the one job where price mattered most.
It costs discipline rather than capital, which makes it the highest-return investment available to a shop that already has the machines.
What buyers ask for and why is set out from their side in mill certs, heat lots and FAI — worth reading, because knowing the buyer’s decision makes your quote easier to write.
The documentation expectations we audit shops against are part of the published shop audit standard. If you already work this way, register.