ASME B89.7.3.1:2001 pdf free download

ASME B89.7.3.1:2001 pdf free download.GUIDELINES FOR DECISION RULES:CONSIDERING MEASUREMENT UNCERTAINTY IN DETERMINING CONFORMANCE TO SPECIFICATIONS.
stringent rejection: the situation when the rejection zone is increased beyond the specification zone by a guard band.20
meaii measurement result: results of repeated measurements are arithmetically averaged to yield a mean measurement result. The mean result is used to determine acceptance or rejection.
data rejection with cause: repeated measurements may indicate that one or more measurement results significantly deviate from the rest of the results of measurement. If the measurement procedure has a documented policy for addressing measurement rejection then this policy takes precedence. Otherwise, measurement resuits may only be rejected if a physical cause can be established. Examples of physical causes for measurement rejection include: improper instrument settings, loose or improperly tixtured components. known transient events such as vibrations caused by doors slamming.
3 REQUIREMENTS FOR DECISION RULES
3.1 Zone Identification
A decision rule must have a well-documented method of determining the location of the acceptance, rejection, and any transition zones.
3.2 Decision Outcome
Each zone of a decision rule must correspond to a documented decision that will be implemented should the result of measurement lie in that zone. While this is automatic for the acceptance and rejection zones by definition, any transition zones must have their corresponding decision outcome documented.
3.3 Repeated Measurements
A decision rule must state the procedure for addressing repeated measurements of the same characteristic on the same workpiece or instrument. See Appendix B for further discussion of this issue.
3.4 Data Rejection
A decision rule must state the procedure for allowing data rejection with cause, that is, rejection of “outliers.” See Appendix C for further discussion of outliers.
4 ACCEPTANCE AND REJECTION ZONES IN DECISION RULES
4.1 Simple Acceptance and Rejection Using an N:1 Decision Rule
This is the most common form of acceptance and rejection used in industry and is the descendant of MILSTD 45662A. Simple acceptance means that product conformance is verified2t if the measurement result lies in the specification zone and rejection is verified otherwise (see Fig. 2), provided that the magnitude of the measurement uncertainty interval is no larger than (he fraction 1/N of the specification zone. In recent years, as tolerances have become increasingly tighter. the well-known ten-to-one ratio has transitioned to a more commonly used ratio of four-to-one (see MILSTD 45662A) or even three-to-one (see International Standard 10012-1). A 4:1 decision rule means the uncertainty interval associated with the measurement.