Chapter 9Profile Tolerances Learning Objectives 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. Technical TermsCoaxial Profi le form and orientation tolerance zoneComposite profi le tolerance Profi le geometric tolerancesCoplanar profi le tolerance Profi le of a line toleranceCoplanar surfaces Profi le of a surface toleranceDisposed Profi le toleranceLocating tolerance zone True profi leNon-uniform profi le Unequally disposed profi leProfi le Unilateral profi le This chapter explains the concepts and techniques of dimensioning and tolerancing to control the profile of geometric shapes. Profile geometric tolerancescontrol the form, orientation, and/or location of straight lines or surfaces, arcs, and irregular curves. Profile TolerancesProfile 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 usedas 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. 315
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