Guides / Choosing a Supplier

ISO 9001, AS9100 or ISO 13485: Which One a Swiss Turned Part Needs

September 24, 2026

Certification names get thrown around loosely in supplier conversations, and it is easy to nod along without knowing what ISO 9001, AS9100 or ISO 13485 actually commits a shop to. Each covers a specific, defined scope, and knowing the difference tells you which one your part actually needs, if any.

Why the certification name matters more than the word “certified”

“We are certified” is not a complete statement. Certified to what standard, in what scope, issued by whom, and does the certificate’s expiry date still hold are the actual questions that matter. A shop is not being evasive by asking you to specify which standard your part requires. It genuinely changes what documentation and internal process the shop has to run, and a shop holding the wrong certification for your industry is no better positioned than one holding none at all.

ISO 9001: the baseline quality management standard

ISO 9001 is a general quality management system standard, not specific to any industry. It requires a shop to document its processes, control nonconforming material, maintain records and continuously look for process improvement. It is the foundation that AS9100 and ISO 13485 both build on, and a very large share of established machine shops hold it, since general industrial and commercial customers frequently expect it as a baseline.

Holding ISO 9001 tells you a shop runs a documented, auditable quality system. It does not by itself tell you anything about the shop’s Swiss machining experience, tolerance capability or track record on your specific material, covered in the comparing quotes guide as one of several separate questions worth asking regardless of certification status.

AS9100: aerospace quality management

AS9100 adds aerospace specific requirements on top of the full ISO 9001 base: additional configuration management, first article inspection requirements, risk management and traceability provisions that matter specifically for flight critical and safety critical hardware. It is the standard most aerospace primes and their suppliers require somewhere in the supply chain, covered in the aerospace guide.

If your part goes into an aerospace program, confirm early whether your specific contract or customer requires the machining shop itself to hold AS9100, or whether the requirement can be satisfied further up your own supply chain. This is a real distinction that changes which shops are even eligible to quote, and it is worth clarifying before sending an RFQ rather than after a shop has already spent time on it.

ISO 13485: medical device quality management

ISO 13485 is the quality management standard for medical device manufacturing, covering design controls, risk management, traceability and the documentation trail regulators expect through a device’s life. Unlike AS9100, ISO 13485 is a standalone standard rather than an addition to ISO 9001, though many certified shops hold both.

Medical device work, covered in the medical guide, often requires ISO 13485 specifically for implantable or patient contact components, while a non critical accessory may be satisfied by a strong ISO 9001 system depending on your own regulatory pathway and device classification. This decision belongs with your regulatory function, not with the machine shop, though the shop should be able to state clearly which standard it holds.

IATF 16949: automotive quality management

IATF 16949 is the automotive industry’s quality management standard, again built on the ISO 9001 foundation with automotive specific requirements around production part approval, defect prevention and reduction of variation. Automotive and EV programs running under a specific OEM or Tier 1 contract frequently require PPAP documentation, covered in the automotive and EV guide, and IATF 16949 is the certification most closely tied to that requirement, though not every automotive Swiss part needs it, covered in the same guide.

What a certification does not tell you

A certification confirms a shop runs a documented quality management system audited against a defined standard. It does not confirm the shop has ever machined your specific material, can hold your specific tolerance, or has capacity for your specific volume. Those are separate questions that belong in the RFQ conversation and the reference check covered in the auditing a supplier guide, regardless of what certification a shop holds.

A certification also does not guarantee zero defects. It guarantees a defined process for catching, documenting and correcting defects when they occur, which is a meaningfully different and more realistic claim than a shop that simply states it never has quality problems.

How to verify a certification is real

Ask for the actual certificate, not just a verbal claim. A real certificate names the specific standard, the scope of what is certified, the certifying body and an expiry date. Confirm the scope matches what you need, since a certificate can cover one facility or one process and not another within the same company, and confirm the expiry date has not passed. This verification step, covered in more depth in the auditing a supplier guide, takes a few minutes and catches the difference between a genuinely certified shop and one that once was or is stretching the truth about its scope.

Deciding whether you actually need a certified shop

Work backward from your own requirement rather than defaulting to the highest certification available. If your customer contract, your device file or a specific regulation names a required standard, that answer is not negotiable and narrows your shop search accordingly. If nothing external requires a specific certification, a shop’s demonstrated experience with your material and tolerance, covered in the comparing quotes guide, is often a more useful signal than certification status alone, and requiring a certification your part does not need adds cost without adding real protection.

Certification renewal and why an expired date matters

A certification is not a one time achievement. Every standard covered here requires periodic surveillance audits and a full recertification cycle, typically every three years, to keep the certificate valid. A shop that earned AS9100 five years ago and has not been through a recent surveillance audit may no longer meet the standard in practice even if the original certificate still hangs on the wall, which is exactly why the expiry date on the actual certificate matters more than the fact that certification was achieved at some point in the past.

Ask for the current certificate, not a description of when the shop first became certified, and check the date. A shop with a certificate expiring in the next few months should be able to tell you where it stands in its renewal audit, and a shop unable to answer that question directly is worth a follow up before you rely on the certification for a program that will run past that date.

A worked example: choosing between two shops on certification alone

Consider a buyer sourcing a bracket for a non critical industrial accessory, comparing two Swiss machining shops. One holds AS9100 aerospace certification. The other holds only ISO 9001. On certification credentials alone, AS9100 looks like the stronger claim, and it is tempting to default to the more heavily certified shop as the safer choice.

The part in question, however, has no aerospace application and no requirement in the buyer’s own contract or specification for AS9100 specifically. Working through the decision properly means asking what AS9100 actually adds for this specific part: additional configuration management, first article documentation and traceability requirements built for flight critical hardware, none of which the buyer’s own program requires or is willing to pay for. The AS9100 shop’s pricing, unsurprisingly, reflects the overhead of maintaining that additional documentation burden across all of its work, including work that does not need it.

In this case the ISO 9001 shop, if its demonstrated experience with the specific material and tolerance is comparable, is very likely the better fit at a lower price, since the buyer is not paying for aerospace specific documentation the part will never use. This is not a universal answer. A buyer whose part genuinely does need AS9100 traceability would reach the opposite conclusion. The point is that certification level should follow from the part’s actual requirement, covered earlier in this guide, rather than being treated as a general quality ranking where more is automatically better.

What this means for your RFQ

State your actual certification requirement plainly on the RFQ rather than a vague request for “a quality shop.” If you need AS9100 or ISO 13485 specifically, say so, since it immediately filters to shops that can genuinely serve you and saves both sides time. If your part has no such requirement, say that too, so a shop does not assume a documentation burden your project does not actually carry.

A certificate is one gate in Swiss machining supplier qualification.

Getting matched with the right shop for your requirement

Send your drawing through the RFQ form and state your certification requirement if you have one. We match your part with up to three shops that run Swiss-type lathes and fit that requirement, and reply within 24 business hours. Where certification is not required, we match on the equipment and material experience your part actually needs instead.

Frequently asked questions

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