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Tham khảo tài liệu 'dimensioning and tolerancing handbook episode 2 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Traditional Approaches to Analyzing Mechanical Tolerance Stacks 9-33 9.3.4 Runout Analyzing runout controls in tolerance stacks is similar to analyzing position at RFS. Since runout is always RFS we can treat the size and location of the feature independently. We analyze total runout the same as circular runout because the worst-case boundary is the same for both controls. Fig. 9-17 shows a hole that is positioned using runout. Figure 9-17 Circular and total runout We model the runout tolerance with a nominal dimension equal to zero and an equal bilateral tolerance equal to half the runout tolerance. The equation for the Gap in Fig. 9-17 is Gap A 2 B - C 2 where A .125 .008 B 0 .003 C .062 .005 9.3.5 Concentricity Symmetry Analyzing concentricity and symmetry controls in tolerance stacks is similar to analyzing position at RFS and runout. Fig. 9-18 is similar to Fig. 9-17 except that a concentricity tolerance is used to control the 0.062 feature to datum A. Figure 9-18 Concentricity 9-34 Chapter Nine The loop diagram for this gap is the same as for runout. The equation for the Gap in Fig. 9-18 is Gap A 2 B - C 2 where A .125 .008 B 0 .003 C .062 .005 Symmetry is analogous to concentricity except that it is applied to planar features. A loop diagram for symmetry would be similar to concentricity. 9.3.6 Profile Profile tolerances have a basic dimension locating the true profile. The tolerance is depicted either equal bilaterally unilaterally or unequal bilaterally. For equal bilateral tolerance zones the profile component is entered as a nominal value. The component is equal to the basic dimension with an equal bilateral tolerance that is half the tolerance in the feature control frame. 9.3.6.1 Profile Tolerancing with an Equal Bilateral Tolerance Zone Fig. 9-19 shows an application of profile tolerancing with an equal bilateral tolerance zone. The equation for the Gap in Fig. 9-19 is Gap -A B where A 1.255 .003 B 1.755 .
