Transforming Art into Science

Overlap also affects the cut point location. As overlap increases, the cut point location is shifted forward, which can result in an unsupported slit (Figure 5). An unsupported slit can act as a rotary razor or burst slit instead of a true shear slit. This is prone to creating more dust and having damaged edges. A prevailing theory is that increased blade penetration will improve cut quality. Unfortunately this has detrimental effects, including slowing the rotational speed of the upper blade, which can create an under-sped nip. Recommended overlap settings are: 0.015˝ to 0.030˝ for tissue and fine papers; 0.020˝ to 0.040˝ for heavy papers and light boards; and 0.030˝ to 0.060˝ for boards.