44 D.P. Rohe Fig. 5.1 Conical test article Fig. 5.2 Test geometry created to ensure consistent scan points between tests The part was tested using three different measurement configurations. The first test used the previous generation 1D SLDV system; this will be referred to throughout this work as the baseline test. The second test used the newer system in a 1D configuration (only utilizing one of the three scanning heads), and the third test used the newer system in 3D configuration (utilizing all three scanning heads). By performing 1D tests with both SLDV systems, a more accurate estimate of the hardware improvements could be obtained. To ensure consistent points were scanned for meaningful comparisons between tests, a test grid was created with 10 axial stations and 16 circumferential stations. The coordinates for each scan point were derived from drawings of the part, with the global x axis along the axis of revolution of the test article. This geometry is shown in Fig. 5.2. In order to point at measurement locations on the part defined by geometry, the lasers first needed to be aligned with the part coordinate system. The alignment procedure was complicated by the lack of sharp features on the part where coordinates were known: the only features available for alignment were the tip of the test article and the ring of holes near the base. The coordinates of these features were extracted from drawings, but there was a significant amount of uncertainty in positioning the lasers at these features: the lasers cannot point at a hole, so some point around the hole needed to be selected. For this test, the point was placed at the boundary of the countersink closest to the tip of the test article. Figure 5.3 shows example laser alignments at features on the test article.
RkJQdWJsaXNoZXIy MTMzNzEzMQ==