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ComputerAided_Design_Engineering_amp_Manufactur.pdf

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FIGURE 4.11(d) Inspection results for a pocket.<br />

rough- and fine-phase alignment procedures, the turbine blade is measured by the CMM having DMIS<br />

features and analyzed in terms of the profile tolerance. Figure 4.12c shows the profile tolerance, i.e.,<br />

maximum deviation, where the iteration number indicates the number of iterations for the transformation<br />

matrix calculation. When the power index of the Chebyshev norm increases, the rate of<br />

convergence decreases, and smaller values of profile tolerance are obtained as shown in Figure 4.12c.<br />

For a typical section of blade, the profile tolerance values for the pressure and suction surfaces are<br />

found to be 0.168 mm and 0.171 mm, respectively. The nominal profile tolerance is 0.200 mm for<br />

both sides. For the radius of the leading and trailing edges, the mean radius is calculated for both<br />

edges based on the measured data points, giving 0.148 mm and 0.154 mm, respectively, for the leading<br />

and trailing edges, while the nominal radii are 0.150 � 0.05 mm for both edges.<br />

4.7 Concluding Remarks<br />

An integrated precision inspection system has been demonstrated for the manufacturing parts having<br />

CAD-defined features. For the inspection of a sculptured surface, three types of s<strong>amp</strong>ling point<br />

strategies have been shown: uniform distribution, curvature dependent distribution, and hybrid<br />

distribution. The line and plane features can be divided into subintervals, and the measurement<br />

points are distributed at random positions in the subinterval. Prime numbers of subintervals can<br />

be considered for the circle/hole features, in order to avoid possible periodic distortion of the

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