PFFC - January 2008 - (Page 44) ROLL ALIGNMENT the rolls. Based on any two rolls having opposite offsets in the vertical and/or horizontal direction, the web might be slacked on one of the sides. (Image 1 Example—Rolls ‘E’ [V:-0.096, H:0.122] and ‘F’ [V:0.013, H:-0.074] have opposite offsets in both the vertical and horizontal direction, indicating the film might be slacked on the operator side.) Second, there might be a wrinkling problem that can occur when moving through a series of rolls with opposite offsets. (Image 1 Example—Going from Roll ‘E’ [ , H:0.122] to ‘F’[ , H:0.074] to ‘G’ [ , H:0.040] may have wrinkling issues because the horizontal values are changing oppositely each time.) Finally, rolls that can be nipped and are used to apply a layer of coating onto a substrate, as shown in Figure 5, can have misalignment problems that lead to uneven coating thickness. This is because there might be an irregular nip pressure across the surface of the roll. One thing to note is that the roll alignment unit can measure rolls in the nipped and unnipped positions. The nipped position is the ideal way in which to measure the rolls since this is the running position. In a set of applicator rolls, one roll is fixed and one is nipped. By setting the fixed roll as the reference roll, the vertical and horizontal offsets can be analyzed for the roll that nips. (Example—The nipped roll in Figure 5 is showing that the operator side is vertically higher by 0.222 in.) This might be why the coating is not spreading uniformly. All of these issues could potentially lead to unplanned downtime and additional costs. Customer Application Figure 5. Example of nipped and fixed rolls in the running position. Figure 6. Vacuum metallizing chamber in the open and non-running position. Nipped Roll V: 0.222" H: 0.010" Fixed Roll V: 0.000" H: 0.000" Figure 8. Final protocol in the closed and running position for Vacumet Corp. F: V: 0.002" H: 0.007" G: V: 0.018" H: -0.006" E: V: 0.010" H: 0.005" H: V: -0.007" H: -0.007" C: V: -0.009" H: 0.004" B: V: 0.007" H: -0.013" D: V: -0.009" H: -0.004" Chill V: -0.015" H: 0.007" Drum V: 0.000" H: 0.000" Since the roll alignment unit was introduced for industrial use, a variety of industries have been able to take advantage of 44 | JANUARY 2008 uSupplier Infot u Pruftechnik Service Inc. | www.pruftechnik-service.com PFFC-ASAP 306 WWW.PFFC-ONLINE.COM http://www.pruftechnik-service.com http://WWW.PFFC-ONLINE.COM
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