Transforming Art into Science

In tangent systems, the ideal cut point is top dead center on the anvil ring. To achieve this position, the upper blade is “set back” from the lower anvil blade. The material may either be deflected around the top blade or under the top blade depending upon the blade profile. If the blade is too far forward, the web begins to fracture ahead of the nip point resulting in an unsupported slit. This can resemble a burst slit or rotary razor where the web is ripping instead of shearing. If the upper blade is too far back, the result is an excessive rub area between the web and the upper blade, which can decrease blade life. The slitter geometry is usually designed into the machine with an expectation for a certain overlap. Fixed knifeholder beams yield more consistency than rotating beam supports.