Also known as log slitting or rewind slitting, roll slitting is a shearing operation that cuts a large roll of material into narrower rolls. The machine used is called roll slitting equipment. The log slitting terminology refers back to the olden days of saw mills when they would cut logs into smaller sections. They would also use these saw mills to cut iron rods into smaller sections; see slitting mill.
For soft materials, there are several methods used for them. Razor blades, straight, or circular blades are being used. Some blades cut through the material while others crush the material against a hard roll. Those are similar to knives and cut the material into narrow strips, which are called coils when being rewound. The cutting blades can be set to a desired width. Some machines have many blades to increase the options of cutting widths, others have just a single blade and can be set to a desired location. The slit material is being rewound on paper or plastic cores on the exit side of the powerful rewinding machine.
For harder materials, such as sheet metal, blades cannot be used. Instead a modified form of shearing is used. Two cylindrical rolls with matching ribs and grooves are used to cut a large roll into multiple narrower rolls. This continuous production process is very economical yet precise; usually more precise than most other cutting processes. However, the occurrence of rough or irregular edges known as burrs are commonplace on slit edges. Also, the geometry of these rolls is determined by specific tolerances in addition to the type of material and workpiece thickness.