Key Questions
The following key questions are answered in this module:
Why are bottom slitters driven slightly faster than the sheet?
The overspeed prevents buckling and bunching up of the sheet at the entrance to the slitters.
There are several different slitting methods - water jet, razor, score/crush, and shear. Which is the most common?
Shear slitting is the most common method used on paper and board machine winders because it gives high quality cuts on a wide range of grades at relatively high speeds.
Why is each bottom slitter driven instead of mounting all of the bottom slitters on a driven carrier roll?
Because the carrier roll diameter must increase as the winder speed and machine width increase, in order to control vibrations, individual motor slitters have become more popular.
They are often referred to as ""knives,"" but only the top slitters look sharp. How do most slitters cut the sheet?
On most winders, the top slitters are sharp circular blades and the bottom slitters are bands. The top blade slightly overlaps the bottom band and is loaded from the side to cut the sheet using a shearing action, like scissors.
When roll sizes change, how are the slitters repositioned?
Slitters can be repositioned manually or automatically. Manual positioning exposes workers to hazards and takes longer, so is more appropriate when slit widths don't change very often.