Guide
ISO 9001 vs AS9100: what a job shop's certification does and does not tell you
Buyers ask for ISO 9001 on a request the way they ask for a drawing format: as a filter. It is a useful one, but it certifies a management system, not a part. AS9100 adds the aerospace requirements on top. Knowing what each one audits tells you when to require it, when a documented inspection is the better ask, and what you are paying for.
Send a drawingUpdated October 8, 2026
What ISO 9001 certifies
ISO 9001 is a quality management system standard. A certified shop has written procedures for how it takes an order, reviews a drawing, controls documents and revisions, calibrates its measuring tools, handles a nonconforming part, and corrects the cause of a problem. A third-party registrar audits those procedures and the records that show they are followed, on a cycle of surveillance and recertification audits.
It does not certify that any particular part meets its drawing. A certified shop can ship a bad part; what the system promises is that the shop will find out why and that its gauges were in calibration when it measured. For a buyer, the practical value is traceability: revision control on your drawing, calibrated inspection, and a paper trail when something goes wrong.
What AS9100 adds
AS9100 contains all of ISO 9001 and adds the aerospace, space and defense requirements: configuration management, risk management on the order, control of counterfeit parts and of special processes (heat treat, plating, NDT) at approved sources, product safety, first-article inspection to AS9102, and tighter control of what is bought and from whom. The audit is deeper and the records are heavier.
AS9100 shops carry that overhead on every job, which is why a non-aerospace part quoted at an AS9100 shop can cost more. If the part is going on an aircraft, a launch vehicle or a defense program, the prime will usually require the certification down the supply chain and there is no choice. If it is a bracket on a packaging machine, you are paying for a system you do not need.
ISO 9001 vs AS9100 at a glance
| ISO 9001 | AS9100 | |
|---|---|---|
| Scope | General quality management | ISO 9001 plus aerospace and defense requirements |
| Audited by | Accredited registrar | Accredited registrar, listed in the OASIS database |
| First-article inspection | Not required by the standard | Required, to AS9102, on new or changed parts |
| Special processes | Controlled per the shop's own procedures | At customer-approved or Nadcap sources where required |
| Counterfeit and traceability | Traceability as the shop defines it | Material and part traceability required |
| Typical holders | Machine shops, fabricators, finishers of every kind | Aerospace machine shops, precision sheet metal, some finishers |
When to require it, and what to ask for instead
- Require AS9100 when your customer or the end use requires it. It flows down; you cannot waive it.
- Require ISO 9001 when you want revision control, calibrated inspection and a nonconformance process without specifying them yourself, or when your own quality system requires approved suppliers to hold it.
- For most industrial work, ask for the outcome instead: a first-article inspection report on the first lot, a material certification with the shipment, a certificate of conformance, and the finish spec on the drawing. Many excellent job shops are not certified and will provide all four.
- Ask who does the special processes. A certified shop that sends plating out is only as good as its plater; a certificate from the plater is the document that matters.
How Amerigo shows certifications
A shop's certifications appear on its quote only when Amerigo has the document or has confirmed it with the shop. A certification a shop claims on its website but has not shown is not cited. If a request needs ISO 9001 or AS9100, put it on the request and it is routed only to shops that hold it.
Questions buyers ask
- Does ISO 9001 mean the parts will be inspected?
- It means the shop has an inspection procedure and calibrated tools. What is inspected on your part is set by the drawing and by what you ask for; a first-article inspection report or a 100 percent inspection on a feature is a line on the quote.
- Is a certified shop more expensive?
- AS9100 shops usually are, because the system costs them on every order. ISO 9001 shops are not necessarily more expensive than uncertified ones; the price is set by the part, the quantity and the shop's load.
- What about ITAR?
- ITAR registration is not a quality certification; it is a legal registration for handling defense technical data. A drawing that is export controlled is sent only to registered shops, and Amerigo asks about export control on every request before it goes out.
About Amerigo. Amerigo is the sourcing network for American manufacturing. More about Amerigo