A Scanning Laser Device Similar To The One Shown In

A scanning laser device, similar to the one shown in Figure 22.12, is to be used to measure the diameter of shafts that are ground in a center less grinding operation. The part has a diameter of 0.475 inch with a tolerance of (0.002 inch. The four-sided mirror of the scanning laser beam device rotates at 250 rev/min. The collimating lens focuses 30( of the sweep of the mirror into a swath that is 1.000 inch wide. It is assumed that the light beam moves at a constant speed across this swath. The photo detector and timing circuitry is capable of resolving time units as fine as 100 nanoseconds (100 x 10-9 sec.). This resolution should be equivalent to no more than 10% of the tolerance band (0.004 inch). (a) Determine the interruption time of the scanning laser beam for a part whose diameter is equal to the nominal size. (b) How much of a difference in interruption time is associated with the tolerance of (0.002 inch? (c) Is the resolution of the photo detector and timing circuitry sufficient to achieve the 10% rule on the tolerance band?

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