In Reply to Parent Post by wrodnigg
Hello Gerry! I think you are asking the wrong question:
Don't ask which of your suppliers is a critical one or not. (and besides, there could be quality critical ones, or business (money) critical ones, or... or... or...)
I think you are looking for quality critical ones.
So take a look at your product and determine the critical components. The suppliers who deliver these components are the critical ones.
I would start with a risk assessment of the product (ISO 14971 could help you).
wrodnigg is correct. There are many ways of viewing the word "critica", but, to quote my well repeated slogan, "never lose sight of the product."
You might consider what other industries and the engineering profession would do. Ask your product designers to undertake a "Failure Modes and Effects Critical Analysis" or FMECA. This is shortened in the automotive industry to be "FMEA". The former was being used many decades ago by nuclear engineers working in the western nuclear power industry - to my certain knowledge, as I once worked in that sector.
Perhaps your designers already have done such an exercise. If so, it should reveal a "ranking" for each component, assemble, part, sub assembly etc. This can be used as a guide in deciding which supplier then is "critical" in that if it delivers defective product, you know the risk to health, safety and of litigation.
As an example: I once authorized an audit of a supplier delivering a particular component whose unit cost was less than $100. The audit cost almost $15000. But, since that item was to be welded into a main pipeline in contact with the nuclear reactor pressure vessel, it was certainly "critical". Its failure would cause a major incident.
But, even if your engineers have actually adopted FMECA (or FMEA) or used fault tree analysis (FTA) is is also important that you thoroughly audit their activities. For this you may need to engage the services of a specialist in your particular field, which I understand is the medical industry. That is because you MUST have confidence in their actual process, methods, analysis and so forth.
I hope this helps.