Posts: 4119
From:West Chester, OH, USA
Registered:

posted 23 April 2000 01:05 PM               

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From: David Chan, Jenny Chan - [email protected]

> ...can anyone tell me that the relationship between AQL and PPM..
> somebody told me that 0.065% AQL = 650PPM, is it true ??
>
> i personally think that it isn't , but cannot get proven evident.. can
> u help me ?
>
> tx..
>
> Jenny Chan...

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Posts: 4119
From:West Chester, OH, USA
Registered:

posted 23 April 2000 09:27 PM               

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I can't help you with the actual numbers off hand, but AQL is Acceptable Quality Level as a per cent. Used in inspection to determine sample size, you decide the AQL level you want and a chart gives you a sample size. Your knowns are the lot size which you look up on the table, and the AQL level you want.

PPM is Parts Per Million which can be converted to a %.

Maybe one of the others can help you out with details and numbers.

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Posts: 498
From:Tullahoma, TN
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posted 24 April 2000 10:13 AM               

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Acceptable Quality Level (AQL) is defined by ANSI/ISO/ASQC A3534 as follows: "When a continuing series of lots is considered, a quality level which for purposes of sampling inspection is the limit of satisfactory process average."

The associated AQL and Lot Tolerance Percent Defective (LTPD) are summarized graphically by the operating characteristic curve.

·somebody told me that 0.065% AQL = 650PPM, is it true ??

Strictly speaking, no. But, a case could be made that if the AQL was, in fact, 0.065%, then the PPM might be 650. The problem is, AQL is an Acceptable Quality level, not the Actual Quality Level. AQL is the quality level that would be detectable under a certain sampling plan.

Also strictly speaking, the LTPD * 10,000 = PPM nonconforming.

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