Inside surface of a large diameter cylinder

  IOMS probes can inspect the inside surfaces of cylindrically symmetric parts with diameters as small as 5 mm and as large as several hundred mm. An example of a part with a large inside diameter is shown in Figure 1. This is a section of a honed aluminum tube 10 inches (254 mm) in diameter. The probe scans the surface with a focused beam of laser light and the detector in the probe detects the reflected light signal. The data is collected and stored in computer memory from which it can be displayed and processed. A photo of the experimental setup is shown in Figure 1.

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Figure 1. 10-inch-ID honed aluminum tube being inspected by IOMS laser scanning probe

 The inspection system can collect and record the data from 100% of the part surface. An image generated from this data is shown in Figure 2. The density at which data can be sampled is variable. In this case the cylinder surface is sampled every 100 µm. Figure 2 cannot display all the detail in this data, but it is possible to zoom in and automatically process the scanned data without repeating the measurement. Figure 3 shows a magnified image of the upper right hand quadrant of Figure 2 

Figure 2. Display of the data from the inner surface of the tube in Figure 1

Figure 3. Magnified image of the upper right quadrant of Figure 2

 The data shows the individual honing marks as well as a scratch on the surface that stands out from the honing mark background. Using  IOMS analysis software to inspect the scratch we can determine the angle and  width of the scratch. This is shown in Figure 4. We see that the angle of the scratch is different than the angle of the honing marks in the same direction.The width of this scratch was determined to be 200 ± 20 µm.

Figure 4. Analysis of the scratch identified and highlighted on the cylinder surface