My company is in aerospace and defense manufacturing. We are in a situation where we must utilize our customer's list of approved special processors for an outside process that their parts require. From their list, only one supplier will bid on performing the required special process (we've tried adding more suppliers to their approved list, but they ended up falling through for various reasons). We've been working with this supplier for years now, but they've had consistent quality problems. Our options appear extremely limited in assisting on improving their process. We've performed audits, and issued corrective actions in an attempt to improve the situation (responses are almost always late and insufficient). Another problem is we are relatively small business to this supplier, so they don't believe they need to improve quality on one particular process for just small potatoes.
My question is: Have you been on either side of a similar problem before, and was their a positive solution for both parties? I'm looking for any suggestions!