Issue link: https://www.e-digitaleditions.com/i/446555
Tablets & Capsules January 2015 31 data were collected using a motorized X-Y stage with step sizes of 1 millimeter in both the width and length dimensions. The resulting maps appear different because of how the data were processed. The left plot was obtained with the highest frequency and, therefore, the smallest beam diameter. In fact, the beam diameter was smaller than the step size, so the fine features of the ribbon's texture are apparent, and the map is pixelated. In contrast, the plot on the right was obtained at the lowest frequency using a beam diameter larger than the step size, and the ribbon texture is smoothed out on the RI map. As noted above, RI values obtained by transmission are directly dependent on the measurement of ribbon thickness at the point where the beam is located. In the case of a high-frequency observation where the beam diameter is similar in size to the pattern of the textured ribbon, it is impossible to measure thickness accurately. The best compromise in that case is to conduct a low- frequency observation using a beam diameter larger than Figure 8 Histograms of RI 1.8 1.78 1.76 1.74 1.72 1.7 1.68 1.66 1.64 1.62 1.6 1.58 1.56 1.54 1.52 1.5 1.48 1.46 1.44 1.42 1.4 1.38 1.36 1.34 1.32 1.3 70 60 50 40 30 20 10 0 Frequency RI High-compaction-force ribbon sections (Figure 7a) Low-compaction-force ribbon sections (Figure 7b) Figure 9 Two-dimensional RI maps of a textured roller-compacted ribbon measured using three different beam diameters 35 30 25 20 15 10 5 Width (mm) Length (mm) Frequency 1.5 THz 1.0 THz 0.5 THz Beam diameter 0.76 mm 1.15 mm 2.29 mm 0 5 10 0 5 10 0 5 10 1.8 1.78 1.6 1.5 1.4 1.3 1.2 RI ACKLEY MACHINE Your best choice for single or bi-layer tablet laser drilling with vision inspection and single tablet rejection. SMALL FOOTPRINT, BIG VALUE. pgulotta@ackleymachine.com www.ackleymachine.com Why settle for anything less? Call Ackley today at 856-234-3626