Every factory can show you a clean line and a wall of certificates. Neither tells you what happens when something goes wrong, which is the only thing you actually need to know before placing an order.
Four questions that work
- Who else do you make this for, and can I see that line running? Not to learn the name — to see whether the process exists outside the sample room.
- What happens to a batch that fails inspection — where does it physically go? A factory comfortable showing you that path usually has one.
- Which parts of this product do you not make yourselves? Almost always some. The answer maps your real supply chain.
- Who was doing this job a year ago? Turnover on a line tells you more about quality stability than any certificate.
The questions that waste the visit
Anything answerable with a yes. « Do you do quality control? » has one possible reply. « Can you meet this tolerance? » has one too, and it is not informative. Replace closed questions with requests to be shown something.
Bring a part, not a drawing. Putting a physical sample on the table changes the conversation faster than any specification document.