S
Hi
This is my first post, but I could do with some help from a wider audience than I have available to me in my company please.
First some background.....
We have a new process manufacturing a new product. Batch sizes are large (typically 100k - 150k). One of the acceptance criteria can only be measured when the product is ready for shipment and is a variable.
We are planning to use variable AQL based sampling plan using ISO6002 (which I believe is comparable to MIL-STD-105E and ANSI/ASQ Z1.4). The AQL for the characteristic is 1.0%.
I've put together a sampling plan using general inspection level II as this is a new process, however the sample size is coming out as 150. This doesn't sound a lot on a 150,000 batch size but it will take at least 1 week to test this. We are producing approx 2 batches / week so this isn't really viable in the long term.
One other complication is that the test method is a destructive test and 150 samples has a significant cost.
Now to the questions....
Under what circumstances can the special inspection levels S-1, S-2 etc be used? I've read that they offer a lower sampling size and are especially useful for destructive and expensive tests.
If special levels are used, then surely some of the confidence in the result must be lost, so what are the implications of using a special inspection level?
Also, if I do chose to use a special level, how can I determine which one is the most appropriate?
Many thanks in advance.
This is my first post, but I could do with some help from a wider audience than I have available to me in my company please.
First some background.....
We have a new process manufacturing a new product. Batch sizes are large (typically 100k - 150k). One of the acceptance criteria can only be measured when the product is ready for shipment and is a variable.
We are planning to use variable AQL based sampling plan using ISO6002 (which I believe is comparable to MIL-STD-105E and ANSI/ASQ Z1.4). The AQL for the characteristic is 1.0%.
I've put together a sampling plan using general inspection level II as this is a new process, however the sample size is coming out as 150. This doesn't sound a lot on a 150,000 batch size but it will take at least 1 week to test this. We are producing approx 2 batches / week so this isn't really viable in the long term.
One other complication is that the test method is a destructive test and 150 samples has a significant cost.
Now to the questions....
Under what circumstances can the special inspection levels S-1, S-2 etc be used? I've read that they offer a lower sampling size and are especially useful for destructive and expensive tests.
If special levels are used, then surely some of the confidence in the result must be lost, so what are the implications of using a special inspection level?
Also, if I do chose to use a special level, how can I determine which one is the most appropriate?
Many thanks in advance.


