Re: Failure Rates for Incoming Components
Matt-
Most of my prior experience has been in automotive and defense and they are very different cultures. In automotive, zero defects were a way of life and at that company (large multinational Tier II), suppliers were expected to maintain PPM's as follows:
'Green' supplier (dock to stock): 0-25 PPM
'Yellow' supplier (normal sampling inspection required): 26-500 PPM
'Red' supplier (tightened sampling inspection required): 501-2500 PPM
'Unacceptable' supplier (discontinue use): 2501+ PPM
A discontinued supplier could slither their way back into our good graces by giving us really, really good 8-D's and then going back to square one of the supplier approval process.
It was different with the military contractors. Both only had suppliers of metals to worry about (about 98% was steel and titanium bar stock, the remainer was oddball stuff like aluminum extrusions) so most of the inspection activity was in-process and final acceptance, not SQD. Defense procurement designated all features as either Critical, Major, Minor, or Unlisted and we had to inspect (in the presence of a DOD procurement specialist, called a 'DCAS') to the old MIL-STD105E (now ANSI/ASQ Z1.4-2003) with the following criteria:
Critical: 100% inspection
Major: 0.65 AQL, Level II
Minor: 4.0 AQL, Level II
Unlisted: Did not require final inspection
But every organization needs to make their own risk/cost analysis and come up with their own 'comfort zone' for supplier quality.
Did any of that blather help?
Regards -John