Browse Prior Art Database

Minimum Cost Sampling Inspection for Accelerated Life Test

IP.com Disclosure Number: IPCOM000085657D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Palanki, HR: AUTHOR [+2]

Abstract

For accelerated life tests, a sampling procedure provides: 1) control on the outgoing product quality, 2) earlier detection of failures, 3) proper feedback to implement corrective action to the process, and 4) cost savings.

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Minimum Cost Sampling Inspection for Accelerated Life Test

For accelerated life tests, a sampling procedure provides: 1) control on the outgoing product quality, 2) earlier detection of failures, 3) proper feedback to implement corrective action to the process, and 4) cost savings.

For a consignment of a finite number of lots (K) and specified producer's risk (Alpha) and consumer's risk (Beta), an efficient sampling procedure for accelerated life tests is developed to assure an instantaneous failure rate (IFR) or average failure rate (AFR), under log normal failure law. This procedure is based upon the following steps:
1. Determine median life (Mu(m)) for specified field conditions.
2. Calculate median life (Mu(s)) for given stress conditions (acceleration factor, (AF) known.
3. Evaluate the appropriate consignment tolerance percent defective

(p(1 - Alpha, p(Beta)) for a given stress period (Ts).
4. Obtain a cumulative sampling plan (N,C) for the consignment.
5. Determine the sampling plan parameters (n(i), c(j)) for the

individual

lots in the consignment and an acceptance number C(I) for the spotty

quality.

Using the inspection procedure illustrated in Fig. 1, a conversational APL program (see Fig. 2 flow chart) is written, which gives as an output in the sampling plan parameters. This information is then used for control and feedback purposes. A typical output is illustrated

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