Multiple Datum Reference Frames

More than one datum reference frame may be necessary for certain parts, depending upon functional requirements. In Fig. 4-24, datum features A, B, and C establish one datum reference frame, while datum features D, B, and C and datum features D, E, and B establish different datum reference frames. Functional Datum Features. Only the required datum features should be referenced in feature control frames when specifying geometric tolerances. An understanding of the geometric control provided by these tolerances (as explained in Sections 5 and 6) is necessary to determine effectively the number of datum references required for a given application. Additionally, functional requirements of the design should be the basis for selecting the related datum features to be referenced in the feature control frame. Figure 4-25 illustrates a part where three geometric tolerances are specified, each having the required number of datum references. Although common datum identifying letters appear in each frame, each combination is a different and independent requirement.

4.5.12 Simultaneous Requirements. Where two or more features or patterns of features are located by basic dimensions related to common datum

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    Why Datum reference reqd?
    8 years ago
  • semhar
    What is a multiple datum reference?
    8 years ago
  • jakub hunter
    How to interpret a multiple datum reference?
    8 years ago
  • elizabeth
    How to interpret datum reference frame?
    9 months ago
  • Dewayne
    How to read multiple datum reference frames?
    2 months ago
  • Mary Sparks
    Do multiple datum reference frame need to be related to each other?
    2 months ago
  • kodi
    Do different datum control frames need to be related?
    2 months ago
  • antony
    Can you use non basic dimensions with a datum reference frame?
    1 month ago

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