S
shadowjade
All,
I represent a manufacturer of complex systems (i.e. not nuts, bolts, or fasteners) with an issue I'd like some input on. A situation has been identified with older product wherein the responsibility in the matter is shared between us (the supplier) and our customer. The response will be to perform a field service campaign to inspect over 900 units.
I have been asked to see if statistical sampling can help reduce the amount of units requiring inspection. I've deferred to ANSI/ASQ Z1.4-2003 and am hopeful for clarification from others here as to my understanding of this standard. Our customer has little or no understanding of the standard so I will have to painstakingly describe it in detail.
At a quantity of 80 units for sampling, we conform to code letter J thereby representing general inspection level II for the fielded quantity of over 900 units. We could withstand 5 rejects at an AQL of 2.5 (normal inspection) at the aforementioned quantity inspected. We can withstand 3 rejections with tightened inspection (same AQL).
Anything rejected beyond this necessitates 100% inspection. In my view, it should be further understood that with both normal and tightened inspection we should be looking at C=0 of zero [0] rejections. The AQLs in these cases are 0.15 and 0.25 respectively.
My questions are: should a switching rule (i.e. if we find 0 defectives before reaching 80 units inspected) be considered? How should I explain the AQL of 2.5 versus 0.15 and 0.25 from a risk perspective?
Please respond when you've had a chance to consider this.
Thank you.
I represent a manufacturer of complex systems (i.e. not nuts, bolts, or fasteners) with an issue I'd like some input on. A situation has been identified with older product wherein the responsibility in the matter is shared between us (the supplier) and our customer. The response will be to perform a field service campaign to inspect over 900 units.
I have been asked to see if statistical sampling can help reduce the amount of units requiring inspection. I've deferred to ANSI/ASQ Z1.4-2003 and am hopeful for clarification from others here as to my understanding of this standard. Our customer has little or no understanding of the standard so I will have to painstakingly describe it in detail.
At a quantity of 80 units for sampling, we conform to code letter J thereby representing general inspection level II for the fielded quantity of over 900 units. We could withstand 5 rejects at an AQL of 2.5 (normal inspection) at the aforementioned quantity inspected. We can withstand 3 rejections with tightened inspection (same AQL).
Anything rejected beyond this necessitates 100% inspection. In my view, it should be further understood that with both normal and tightened inspection we should be looking at C=0 of zero [0] rejections. The AQLs in these cases are 0.15 and 0.25 respectively.
My questions are: should a switching rule (i.e. if we find 0 defectives before reaching 80 units inspected) be considered? How should I explain the AQL of 2.5 versus 0.15 and 0.25 from a risk perspective?
Please respond when you've had a chance to consider this.
Thank you.