Method and apparatus for controlling the speed of a continuous sheet of material

A first apparatus that performs a first operation on a continuous sheet of material, comprising:

• an apparatus that performs the first operation on at least a portion of the continuous sheet of material in a predetermined period of time;
• a servo unit that moves a predetermined length of the continuous sheet of material into the apparatus at a predetermined rate, wherein the servo unit is operable to alter the predetermined length of the continuous sheet of material moved into the apparatus;
• an outfeed device that accumulates the continuous sheet of material after the first operation is performed;
• and
• an outfeed sensor that measures a length of the continuous sheet of material in the outfeed device, wherein a rate of the first operation is adjustable to provide a predetermined length of the continuous sheet of material in the outfeed device.

A method of controlling an input rate and an output rate on a continuous sheet of material, comprising:

• accumulating a first length of slack in the continuous sheet of material before a first apparatus performs a first operation;
• moving a predetermined length of the continuous sheet of material into the first apparatus by a servo unit;
• performing the first operation with the first apparatus on the continuous sheet of material, wherein the first apparatus can perform the first operation at a rate that is variable, and wherein the servo unit is operable to alter the predetermined length of the continuous sheet of material moved into the first apparatus;
• accumulating a second length of slack in the continuous sheet of material after the first apparatus performs the first operation;
• monitoring the first length of slack and the second length of slack;
• and
• adjusting the rate of the first operation performed by the first apparatus to alter at least one of the first length of slack and the second length of slack.