Approving an alternate supplier is not a mood decision. It is a conclusion supported by process capability, material and special-process evidence, inspection method, prior similar work, and the customer gates your program requires. Quality and sourcing leaders approve too early when reputation or a confident call substitutes for a complete packet.
Start with process capability tied to the drawing in effect. Equipment class, tolerance band, and material experience should match the part requirement, not a generic shop profile. If the route includes finishing, heat treat, or NDT, verify scope for those steps too, including whether work stays in-house or flows to an approved special-process source.
Material and special-process evidence comes next. Cert scope, WPS/PQR where welding applies, and coating or plating approvals should cover the spec on the BOM. Expired or narrowly scoped certs are a common gap. Prior similar work helps when it reflects comparable geometry, alloy, and inspection load, not just the same NAICS label.
Inspection assets and method belong in the review. Does the supplier have the gage resolution, CMM reach, or NDT technique your quality plan expects? First-article and ongoing inspection requirements should be agreed before approval state moves, not negotiated after the first production lot ships.
Customer gates may add PPAP level, source approval, audit scope, or notification rules that extend beyond internal readiness. List them explicitly in the qualification packet so approvers see what remains open.
Make missing proof explicit before approval, not after production starts. A structured view of complete, partial, and missing evidence lets teams hold approval until the route is credible. Manufacturing capability verification is the work of closing those gaps with records, not of assuming they will close on their own.