an excellent post from someone with experience, who has I am sure, experienced some if not all of the unforeseen things in the past, that can happen whilst preparing for a production run of a product.

"Here are some fundamental principles to reduce risk:

1. Avoid single-source critical components whenever possible
2. Pre-qualify alternatives before you urgently need them
3. Monitor lifecycle status
4. Maintain strategic safety stock for long lead-time parts
5. Work with suppliers who provide traceability and real inventory visibility"

All very important things to bear is mind, both during initial and for follow on production runs, so that one is prepared for what may happen, and does not have to react in panic when it does.