After studying this chapter, you will be able to:
❍ Describe the purpose of profi le geometric tolerances.
❍ Apply or interpret profi le geometric tolerances on drawings.
❍ Draw or interpret profi le of a line tolerances.
❍ Explain methods used to apply bilateral tolerances.
❍ Explain methods used to apply unilateral tolerances.
❍ Apply or interpret profi le of a surface tolerances.
❍ Draw or interpret coplanar profi le tolerances.
❍ Explain the types of controls specifi ed by composite profi le tolerances.
Coaxial Profi le form and orientation tolerance zone
Composite profi le tolerance Profi le geometric tolerances
Coplanar profi le tolerance Profi le of a line tolerance
Coplanar surfaces Profi le of a surface tolerance
Disposed Profi le tolerance
Locating tolerance zone True profi le
Non-uniform profi le Unequally disposed profi le
Profi le Unilateral profi le
This chapter explains the concepts and techniques of dimensioning and
tolerancing to control the profile of geometric shapes. Profile geometric tolerances
control the form, orientation, and/or location of straight lines or surfaces, arcs, and
Profile can be characterized as the outline of an object represented either by
an external view or a cross section through the object. The true profile or actual
desired shape of the object is the basis of the profile tolerance. The true profile is
defined by basic dimensions. The profile tolerance specifies a uniform boundary
along the true profile within which the elements of the surface must lie. Profile can
be used to control form or combinations of size, form, and orientation. When used
as a refinement of size, the profile tolerance must be contained within the size
tolerance. Profile geometric tolerances are always regardless of feature size. Datum
reference can be applied with boundary conditions (RMB, LMB, MMB) if the datum
feature is a feature of size.