The availability of advanced CAD design tools and manufacturing capabilities often incorporate complex, blended shapes. These surfaces are not easily defined by the prismatic shapes that we have grown accustomed too and requires an offset profile band, or halo surrounding the CAD model.

Test Criteria for Compliance to Engineering Requirements
Stated Compliance to the engineering requirements as defined per the ASME Y14.5 and Y14.5.1 Standards and therefore FDA 21 CFR PART 11 require compliance with the following “Test Criteria.”

1. Size, which is defined as having two parts based on “Limits of Size” criteria defined in section 2.3 of the Y14.5.1 Standard. This requires compliance to both the “Actual Local Size” and “Actual Mating Size.”

2. Datums which are based on criteria defined in section 4.3 of the Y14.5.1 Standard which requires:
   1. Datum “Features of Size at RFS” (Regardless of Feature Size) to be simulated as “Actual Mating Envelopes.”
   2. Datum “Features of Size at MMC (Maximum Material Condition) or LMC (Least Material Condition)” to be simulated as “Virtual Conditions.”

   3. “Multiple Features of Size” defined as a “Single Datum” to be “Simulated as Patterns” based on “Actual Mating Envelopes” (RFS) or “Virtual Conditions” (MMC or LMC).

3. Position Tolerances which are based on criteria defined in section 5 of the Y14.5.1 Standard which requires:
   1. Analysis of axes based on “Actual Mating Envelope” principle.
   2. Analysis of “Bonus Tolerance” based on applicable features defined at MMC or LMC.
   3. Analysis of “Simultaneous Requirement” which requires all features to simultaneously be within their respective tolerances when the feature control frames have the same datum, in the same sequence with the same datum feature modifiers.

   4. Analysis of Single-Segment -vs- Composite Feature Control Frames.

4. Profile Tolerances which are based on criteria defined in section 6.5 of the Y14.5.1 Standard which requires:
   1. Minimum Zone fitting algorithms are used.
   2. Profile results must always look for the smallest possible deviation of the actual geometry (worst case measured point) from nominal geometry, ideally a CAD model that can be compared to the profile tolerancing in the feature control frame.

   3. Must ensure “Simultaneous Requirements” are being met which requires all features to simultaneously be within their respective tolerances when the feature control frames (Single-Segment) “have the same datum, in the same sequence with the same datum feature modifiers.”

5. Revision changes of software must be validated to original “Test Criteria” for continued “Proof of Compliance” to ensure ongoing integrity of measured results and conformance to requirements.