Nadcap Special Process Outsourcing: Managing Approved Suppliers

What Counts as a Special Process

A special process is one where the result cannot be fully verified by later inspection, so the process itself is controlled. In machine shop work that usually means heat treating, chemical processing (anodize, passivation, chromate conversion, plating), nondestructive testing (fluorescent penetrant, magnetic particle, ultrasonic, radiography), welding and coatings. Nadcap accredits these by commodity, such as heat treating, chemical processing, NDT and welding.

Typical specifications are AMS 2750 for pyrometry, AMS 2759 for steel heat treat, MIL-A-8625 for anodize, AMS 2700 for passivation, and ASTM E1417 for penetrant inspection. Always take the specification from the drawing and PO, not from the processor's standard sheet.

Verifying Accreditation and Prime Approval

Accreditation is process and scope specific, so a processor listed as accredited for chemical processing may not be accredited for the particular method you need. Customers add another layer: primes keep their own approved processor lists, often with prime-specific specifications for the same process.

• Check the processor's current Nadcap status, scope and expiry in eAuditNet, and record the date you checked
• Match the drawing's specified process and class or type to the processor's approved scope
• Confirm the customer or prime approval for that processor where the PO requires it
• Review the processor's own sub-tier control, for example outsourced NDT personnel qualification to NAS 410
• Re-verify on a schedule, since status changes between audits

Flow-Down on the Outside Processing PO

3 expects you to tell the external provider what is required: the process, specification and revision, acceptance criteria, qualification of personnel, records to retain, right of access and any customer-specific notes. A bare PO line saying anodize per drawing is a common audit finding. Build a PO template per commodity with the standard notes, and have the ERP print the drawing process callouts and quality clauses automatically.

Require a certificate of conformance that names the part number, lot or serial, process specification and revision, and results where applicable. Inspect incoming certs for completeness before parts move to the next operation.

Scheduling Around Processor Lead Times

Special process vendors are frequently the longest and least predictable leg of the job. Turnaround quoted at five days can stretch when a tank is down or a furnace load is waiting for a full batch. Add the real lead time to your router as an outside operation, track actual vendor performance, and ship parts to processors in groups only when it does not break delivery dates.

If your ERP supports vendor lead-time history, use it; otherwise a monthly review of on-time performance by processor is a simple start. Primes score you on delivery, not on your vendor's problems.

Automating the Paperwork Without Losing Control

A private AI model can read the drawing for special process callouts, look up the approved processors in your supplier list, check certificate text against the PO requirements, and flag missing items such as an absent spec revision or lot number. It should surface discrepancies for your quality team rather than auto-accept certs. Not worth it for a shop that outsources only one or two processes to a single long-standing vendor, where a clear template and a periodic audit are enough.