Defining sampling plan for different AQL

trololo

Registered
Hello Everyone !

First post here after > 7 yrs reading the forum :)
I don't think my question was previously answered and it is in relation with the ISO 2859-1 Standard.

My problem is the following :
I want to inspect a batch of plastic part for cosmetic defects, some are judged major with an AQL set to 1.0% and some are judged minor with an AQL set to 4.0%. I inspect per general level I (the inspection is long and tedious and for cosmetic aspect I don't think it is worth using II level) and my batch is 500 pieces. According to the ISO standard I have a sampling size code F (20 parts)
If I want to inspect the major defects for the AQL 1.0% I need to switch and use sampling size E (13parts).
BUT (and here is my problem) :
What should I use for the inspection of the minor defect : Is it fine to stay with a E sampling ?
Practically this makes sense but does it work with the thoery ? The good aspect of staying with the E samling is that I do not have to ask my operator to perform another sampling + there is a risk to find major defect in the new sampling. In addition this raises questions as to how to do this new sampling : should I take a complete new sample ? or should I just pick 7 additional parts ?

Could you please advise ?
thanks !!
Robin
 
"If this procedure leads to different sample sizes for different classes of nonconformities or nonconforming items, the sample size code letter corresponding to the largest sample size derived may be used for all classes of nonconformities or nonconforming items, when designated or approved by the responsible authority."

I take this to mean that you should use the sample size of 20 (Code F) for both inspections.
 

Bev D

Heretical Statistician
Leader
Super Moderator
The criteria is the same for all products: the severity of the defect and your Customer’s tolerance for defects.
Remember that the AQL is the level of defects that is ACCEPTABLE to ship. The RQL or (LTPD) is the defect rate that is NOT ACCEPTABLE to ship...
 
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