IFS Apps 9 Update 10:

We’re looking at purchasing control plans, and wanting to begin to use those in lieu of the other system we currently use to do inspections on incoming parts.

For most cases, we find that the purchasing control plans will work very well.
 

We have a particular case, however, where we are wanting to drive a certain sample size based on the lot quantity, using the ASQR-20.1 (aerospace) standards.

This is difficult because this particular AQL plan is based on a c=0 acceptance. Meaning, the quantity driven for inspection is presuming that there are no non-conforming items within the sample size. Using the existing acceptance sampling logic, it looks as if we’re forced to adhere to the whatever the system generated inspection quantity values are, which do not seem to be based on a c=0, but rather what the “acceptable” c= value is based on some background math that I can’t see.

Given the particular constraints, we cannot simply use a sample percentage either, it would seem.

I’ve tried several things to drive the appropriate sample size and I keep coming up empty handed.

Is there a way to drive a specific sample size/quantity to inspect, based on the lot size?

Based on a .65% AQL, with c=0, the ranges we’re dealing with are:
1-150: All, or 20 PCS.
151-280: 29 PCS
281-1,200: 47 PCS
1,201-3,200: 53 PCS
3,201-10,000: 68 PCS
10,001-35,000: 77 PCS
35,001-150,000: 96 PCS
150,001-500,000: 119 PCS
500,001 and over: 143 PCS

Is there any way that any one has found to drive an appropriate sampling size for their purposes, based on lot quantity?

Am I missing something? Does anyone have any insight here?