GD&T - Geometric Dimensioning and Tolerancing Composite Feature Control Questions and Answers

Question 1

In a composite position feature control frame, what is the primary function of the lower segment, also known as the Feature-Relating Tolerance Zone Framework (FRTZF)?

Accepted Answer

It refines the orientation of the pattern to any datums repeated from the upper segment and controls the feature-to-feature relationship.

Answer

It controls the location of the pattern relative to the specified datums.

Answer

It defines the size tolerance for each feature within the pattern.

Answer

It establishes a completely independent tolerance that supersedes the upper segment.

Question 2

A composite profile tolerance is applied to a surface. The upper segment specifies a tolerance of 0.8 mm to datums |A|B|C|. The lower segment specifies a tolerance of 0.2 mm to datum |A|. How does the lower segment constrain the tolerance zone?

Accepted Answer

It creates a 0.2 mm wide tolerance zone that is only constrained in orientation (perpendicularity) to datum A.

Answer

It creates a 0.2 mm wide tolerance zone that is located and oriented by datums A, B, and C.

Answer

It requires the surface to be within 0.2 mm of its true profile, but the tolerance zone can translate in any direction.

Answer

It refines the location of the surface relative to datum A only.

Question 3

Which of the following statements correctly describes the key difference between a composite position tolerance and a two single-segment position tolerance?

Accepted Answer

In a composite tolerance, the lower segment only controls orientation to datums, while in a two single-segment callout, the lower segment controls both location and orientation to its specified datums.

Answer

There is no functional difference; they are two ways of specifying the same requirement.

Answer

A two single-segment tolerance requires the same datums to be referenced in both segments, whereas a composite tolerance allows different datums.

Answer

Composite tolerances can only be applied to patterns of holes, while two single-segment tolerances can be applied to any feature.

Question 4

A designer needs to control a pattern of four mounting holes. The location of the entire pattern on the part has a generous tolerance (e.g., 1.0 mm), but the spacing between the holes must be held to a much tighter tolerance (e.g., 0.1 mm) to ensure a mating part fits correctly. Which GD&T callout is most appropriate for this scenario?

Accepted Answer

A composite position tolerance with Ø1.0 mm in the upper segment and Ø0.1 mm in the lower segment.

Answer

A single position tolerance of Ø0.1 mm.

Answer

A profile of a surface tolerance.

Answer

A perpendicularity tolerance applied to each hole individually.

Question 5

When interpreting a composite feature control frame, what is the term for the tolerance zone defined by the upper segment?

Accepted Answer

Pattern-Locating Tolerance Zone Framework (PLTZF)

Answer

Feature-Relating Tolerance Zone Framework (FRTZF)

Answer

Secondary Tolerance Zone Framework (STZF)

Answer

Datum-Relating Tolerance Zone Framework (DRTZF)

Question 6

In a composite position tolerance, if the primary datum is repeated in the lower segment, but the secondary and tertiary datums are omitted, what is the effect on the Feature-Relating Tolerance Zone Framework (FRTZF)?

Accepted Answer

The FRTZF is constrained in orientation to the primary datum but is free to translate and rotate relative to the secondary and tertiary datums.

Answer

The FRTZF is located by the primary datum and oriented to the secondary and tertiary datums.

Answer

The FRTZF is fully constrained and cannot move relative to the PLTZF.

Answer

The FRTZF becomes invalid because all datums from the upper segment must be repeated.