This standard is issued under the fixed designation B; the number 1 This test method is under the jurisdiction of ASTM Committee B08 on Metallic. ASTM B_机械/仪表_工程科技_专业资料。 Designation: B – 88 ( Reapproved ) Standard Test Method for Attribute Sampling. Purchase your copy of ASTM B – 88() as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards.
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If every article in an inspection lot conforms to its requirements, every article in the sample will conform also.
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The plan of Table 4which is used for destructive testing, is not from the Military Standard. The specific plans selected are identified bb602 Tables of this test method. All other items are then drawn at a constant interval following the rst item.
ASTM B – 88() Standard Test Method for Attribute Sampling of Metallic and Inorganic Coatings
Last previous edition approved in as B — 88 In plans of this type, several articles of product are drawn from a production lot. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For example, if a sample of 50 articles drawn in accordance with Table 2 is found to contain two defectives with respect to thickness and a third one aztm respect to appearance, the inspection lot is acceptable because although three articles were defective no more than two, the acceptance number, were defective with respect to a single requirement.
It is the worst condition that can occur under rectifying inspection. In accordance with Table 3, a sample of items is to be drawn.
ASTM B602 – 88(2016)
Link to Active This link will always route to the current Active version of the standard. After the rst item is taken, the remaining items in the required sample are drawn by selecting every 24th item from the lot until are selected. The sample then consists of articles numbered 31, 20, 8, 26, 53, 65, 64, 46, 22, 6, 41, 67, and The plan of Table 4, which is used for destructive testing, is not from the Military Standard.
A table of random numbers Table A1. Link to Active This link will always route to the current Active version of the standard. There may be instances in which tighter or looser plans or ones that are more discriminating are desired. The poorest average quality level that can result from the use of a given sampling plan when screening of rejected lots is done is called the Average Outgoing Quality Limit AOQL.
For example, the articles may be expensive or the inspection lot may be small. A random number from 1 to 24 is selected either from a table see A1. Also, some test methods are destructive, in which cases sampling inspection must be used to avoid destroying the lot.
This quantity may be a shipment from a supplier, articles that are ready for a subsequent manufacturing operation, or articles ready for shipment to a customer. Screening of rejected lots will substantially increase the cost of inspection if the incoming lots are much worse than AQL quality.
In the extreme case of every article in an inspection lot being nonconforming, a sample will always indicate that the lot is unacceptable. Screening is to be used only when required by the purchaser. Additional plans that may serve these needs are given in Guide B The larger the sample, the smaller this risk but the larger the cost of inspection.
This standard does not contain the Military Standard’s requirement for tightened inspection when the quality history of a supplier is unsatisfactory. The AQL is the quality level that is considered to be acceptable.
These are explained in Test Method B We aastm cookies to make our website easier to use and to better understand your needs. This last plan utilizes smaller samples and so reduces the cost of inspection but with a sacrice in the ability to distinguish between acceptable and unacceptable lots.
The larger the sample, the smaller this risk, but, the larger the cost of inspection. Sampling plans based on inspection by variables are given in Test Method B NOTE 4—The acceptability of an inspection lot is determined with respect to each requirement independently from all other requirements. The permission to use test specimens and the requirements covering them astn their use should be set forth in the applicable coating specication, purchase order, or other governing document.
If the standard deviation of the process is not known, the standard deviation of the sample is calculated and used. For this reason, there are no AQL, etc. If the test method is destructive, the sample size shall astmm that directed in 8.
Electrodeposited coatings, Inorganic coatings, Inspection, Inspection and verification, Metallic coating, Paint related coatings, Protective coatings, Sampling.
The fourth plan is intended to be used when the inspection methods are destructive. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
The number of nonconforming articles in accepted lots is controlled by the size of the sample and the criteria of acceptance that are placed on the sample.
If one or more of these conditions are not met, a variables plan cannot be used. Bias can be avoided by numbering the articles, randomly selecting a group of numbers equal to the sample size, and inspecting the articles with the selected numbers. This standard does not contain the Military Standard’s requirement for tightened inspection when the quality history of a supplier is unsatisfactory. When the incoming lots are of a good quality level, the ashm quality level of a series of lots will be even better when the rejected lots are screened and resubmitted.
There is no AOQL for the plans used with destructive tests because destructive tests cannot be used to screen rejected lots.