Reporting GD&T data on First Article Reports

[kelroy]

Does anyone know of a specification, standard, or industry best practice reference that addresses basic dimensions in first article inspections? I've checked AS9102 and haven't found any guidence.

The question is whether the basic dimension must be referenced in the FAI (First Article Inspection) Report, or if the verification/reporting of the locattion of the feature (controlled by the tolerance in the feature control frame) is sufficient? Example provided:

Drawing Req't: Hole with True position of .005 RFS, Basic dims are 1.000 and 2.000 from the planar XY datums (RFS).

FAIR: True position reported as ".003 RFS"

I contend that the only contractual requirement is that the true position is reported, since it's value is calculated based on the reference datums and basics, even though general "best practice" would be to report the measurement of the location used to calculate the location of the feature. Looking for hard industry standards though.

 

[mechengdude]

I agree with your point. If it is reported at .003 RFS then by definition it meets the basic dimension requiremnt. End of story. A couple of other comments. You may get some good advice if you post this on the GD&T forum. Also, if you have a difficult customer then just add the basic dimensions to the report and always report them as exactly shown on the print. Again, by definition there is no tolerance associted with the actual basic dimension.