Metal finishing processes use specialized techniques and equipment so organizations often outsource some of these activities to specialist suppliers. But in doing so, it is important to understand the outsourcing requirements included in the international quality standard ISO 9001:2008 and its aerospace equivalent AS EN 9100 rev C.

Both standards state in section 4.1 – "Where an organization chooses to outsource any process that affects product conformity to requirements, the organization shall ensure control over such processes" and "Ensuring control over outsourced processes does not absolve the organization of the responsibility of conformity to all customer, statutory and regulatory requirements." So even when outsourced to a specialist supplier, the control and conformance of the outsourced process is still the responsibility of the organization.

Control is primarily exercised through the purchasing procedures and paragraph 7.4.2, Purchasing Information, requires the purchase order to include, as appropriate, details of procedures, processes, equipment and operator qualification. In a case of outsourced shot peening this may include reference to an approved procedure or technique, the process specification e.g. AMS2430S and the shot peening machine approved for that process. Operator qualification is well defined in Nadcap checklist AC7117 rev A or in proprietary specifications and MFN training will satisfy the knowledge aspect of this requirement. AS EN 9100 also explicitly requires that requirements for production process verification be included in purchasing information, so the frequency and method of intensity verifications and coverage inspection are required. These verifications are adequately defined if a detailed process specification such as AMS 2430S is stated.

AMS2430S also contains a comprehensive list of order information that should be provided by the organization otherwise the specialist supplier may use the provisions of the specification in default of missing information. Even if an alternative process specification applies, it is useful to review AMS2430S as it provides good guidance on this topic.

Paragraph 7.4.3 of the standards requires that the organization verify the product when it is delivered. Shot peening is a special process so inspection alone is not full verification. AS EN 9100 includes reference to objective evidence of verification such as certificates of conformity (CoC), verification test results and process records. So the information on the CoC, intensity verification results and coverage inspection records will provide objective evidence for verification of the shot peening process. AS EN 9100 is explicit on an important principle – "Customer verification activities performed at any level of the supply chain should not be used by the organization or the supplier as evidence of effective control of quality and does not absolve the organization of its responsibility to provide acceptable product and comply with all requirements." So the fact that a customer accepts a part does not absolve the supplier of its responsibility to perform all the required verifications and ensure full conformance.

This verification is only meaningful if the organization has validated the shot peening process initially. This is because peening is a "special process" wherein the resulting output cannot be verified by subsequent monitoring or measurement and, as a consequence, deficiencies become apparent only after the product is in use. Paragraph 7.5.2 gives requirements on the validation of the process, including procedures, qualification requirements and equipment. So the organization must initially examine and validate these aspects of the specialist supplier’s proposed process.

And finally, a comment relating to the outsourcing of equipment calibration; section 7.6 requires calibration or verification against measurement standards traceable to international or national measurement standards, where these exist. In shot peening the Almen gauge may be outsourced for calibration and the usual standard is SAE J442. So to satisfy ISO 9001 requirements the purchase order may read "Calibrate using the methods and acceptance criteria of SAE J442, latest revision." AS EN 9100 has additional requirements that the organization "define the process employed for their calibration/verification including details of… check method and acceptance criteria." In this and similar cases, an organization may not have full knowledge of the technical requirements and methods for calibration and in this case the organization should request a full copy of the calibration procedure and report from the calibration supplier. This can be checked against their customer’s requirements, if necessary by sending it to the cognizant engineering authority and obtaining documented approval from them. This procedure can then be referenced on the purchase order so that the organization has control of the calibration, even if they lack the specialist knowledge of the calibration supplier.

This is a short review of a complicated subject, so readers are encouraged to obtain and review the standards for themselves and seek professional assistance if they have any doubts about their organization’s compliance.

For questions contact paul@mfn.li

Standards Forum
by Paul Huyton,
MFN Course Director World Wide
more information at www.mfn.li/trainers