ISO/TR 14253-6:2012 幾何学的製品仕様（GPS）—ワークピースと測定機器の測定による検査—パート6：機器とワークピースの受け入れと拒否に関する一般的な決定ルール | ページ 6

3.1

acceptance limit

upper or lower bound of permissible measured quantity values

Note 1 to entry: For workpieces, the acceptance limits are often called the gauging limits.

Note 2 to entry: In the case of a simple-acceptance decision rule, the acceptance limits equal the specification limits.

3.2

acceptance zone

acceptance interval

interval of permissible measured quantity values

Note 1 to entry: Unless otherwise stated in the specification, the acceptance limits belong to the acceptance interval.

Note 2 to entry: In ISO 14253‑1, the stringent acceptance zone defined by the default decision rule is (loosely speaking) called the conformance zone because of the high probability that a measurement result in this zone corresponds to a conforming product.

Note 3 to entry: A measured value that is in the acceptance zone does not necessarily correspond to a (truly) conforming characteristic due to measurement uncertainty.

3.3

binary decision rule

decision rule with only two possible outcomes, either acceptance or rejection

3.4

conforming

having the quality that its true value lies within or on the boundary of the tolerance zone or specification zone

Note 1 to entry: In this part of ISO 14253, it is assumed that the true value of the measurand is essentially unique.

3.5

consumer's risk

probability that a particular accepted item is nonconforming

Note 1 to entry: In ISO/IEC Guide 98‑4, this is called “specific consumer’s risk”.

3.6

decision rule

documented rule that describes how measurement uncertainty will be allocated with regard to accepting or rejecting a product according to its specification and the result of a measurement

3.7

guard band

interval between a tolerance limit and a corresponding acceptance limit

Note 1 to entry: In this part of ISO 14253, the term “tolerance limit” is synonymous with “specification limit”.

3.8

measurement capability index

C_m

tolerance divided by a multiple of the standard measurement uncertainty associated with the measured value of a property of an item

Note 1 to entry: In this part of ISO 14253, the multiple is taken to be 4; hence, in the case of measuring a characteristic for conformance to a two-sided tolerance zone of width T, C_m = T/4u_m, where u_m is the standard uncertainty associated with the measurement of the characteristic.

Note 2 to entry: In this part of ISO 14253, the term “tolerance limit” is synonymous with “specification limit”.

3.9

nonconforming

having the quality that its true value lies outside the boundary of the tolerance zone or specification zone

Note 1 to entry: In this part of ISO 14253, it is assumed that the true value of the measurand is essentially unique.

3.10

process distribution

probability distribution characterizing reasonable belief in values of a characteristic resulting from a manufacturing process

Note 1 to entry: The form of this distribution can be inferred from a frequency distribution (usually displayed in a histogram) of measured characteristics from a large sample of items.

3.11

process capability index

C_p

index describing process capability in relation to a specified tolerance

Note 1 to entry: This definition is specific to this part of ISO 14253 and is a special case of the more general definition given in ISO 21747.

Note 2 to entry: In this part of ISO 14253, the process distribution is centred in the middle of the tolerance (i.e. specification) zone, and the index is the ratio of the zone width to 6 standard deviations of the production distribution.

3.12

producer's risk

probability that a particular rejected item is conforming

Note 1 to entry: In ISO/IEC Guide 98‑4, this is called “specific producer’s risk”.

3.13

relaxed acceptance

situation when the acceptance zone is increased, and partially outside, the specification limit by the amount of a guard band

Note 1 to entry: Relaxed acceptance should be used with caution as it increases the size of the acceptance zone and hence decreases the probability that an accepted product is a conforming product.

Note 2 to entry: Relaxed acceptance and stringent rejection occur together in a binary decision rule.

Note 3 to entry: The magnitude (in mm) of the relaxed guard band should be specified instead of % U to avoid poor metrology (large U) increasing the number of acceptable workpieces.

Note 4 to entry: See Figure 2 as an example of relaxed acceptance.

3.14

relaxed rejection

situation when the rejection zone is increased, and partially inside, the specification limit by the amount of a guard band

Note 1 to entry: Relaxed rejection increases the size of the rejection zone and hence decreases the probability that a rejected product is a nonconforming product.

Note 2 to entry: Stringent acceptance and relaxed rejection occur together in a binary decision rule.

Note 3 to entry: See Figure 1 as an example of relaxed rejection.

3.15

rejection zone

rejection interval

interval of non-permissible measured quantity values

Note 1 to entry: In ISO 14253‑1, the stringent rejection zone defined by the default decision rule is (loosely speaking) called the nonconformance zone because of the high probability that a measurement result in this zone corresponds to a nonconforming product.

3.16

simple acceptance

acceptance criterion where the specification zone equals the acceptance zone

Note 1 to entry: A common binary decision rule combines simple acceptance with simple rejection.

3.17

simple rejection

rejection criterion rule where the rejection zone equals everything outside of the specification zone

Note 1 to entry: A common binary decision rule combines simple acceptance with simple rejection.

3.18

stringent acceptance

guarded acceptance

situation when the acceptance zone is decreased, and completely inside, the specification limit by the amount of a guard band

Note 1 to entry: Stringent acceptance decreases the size of the acceptance zone and hence increases the probability that an accepted product is a conforming product.

Note 2 to entry: Stringent acceptance and relaxed rejection occur together in a binary decision rule.

Note 3 to entry: The default rule ISO 14253‑1 is an example of stringent acceptance with a 100 % U guard band.

Note 4 to entry: See Figure 1 as an example of stringent acceptance.

3.19

stringent rejection

situation when the rejection zone is decreased, and completely outside, the specification limit by the amount of a guard band

Note 1 to entry: Stringent rejection decreases the size of the rejection zone and hence increases the probability that a rejected product is a nonconforming product.

Note 2 to entry: Relaxed acceptance and stringent rejection occur together in a binary decision rule.

Note 3 to entry: See Figure 2 as an example of stringent rejection.

3.20

transition zone

range of values of a characteristic that is neither in the acceptance zone nor rejection zone

Note 1 to entry: There may be more than one transition zone; each should be separately labelled.

Note 2 to entry: A binary decision rule does not have a transition zone.

3.21

uncertainty interval

<of a measurement> interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand

Note 1 to entry: The width of the uncertainty interval is typically twice the expanded uncertainty.

Note 2 to entry: The uncertainty interval is also known as the coverage interval [ISO/IEC Guide 99:2007, 2.36].

Note 3 to entry: The uncertainty interval for the mean of repeated measurements may decrease with increasing numbers of measurements.