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Method and system for registering pre-produced webs with variable pitch length

  • US 6,955,733 B2
  • Filed: 12/20/2002
  • Issued: 10/18/2005
  • Est. Priority Date: 12/19/1997
  • Status: Expired due to Fees
First Claim
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1. A method for registering an off-line produced web having pre-produced objects longitudinally spaced at a pitch interval to a converting line manufacturing disposable absorbent articles, such as diapers, pants, feminine hygiene articles, and the like, or a component of a disposable absorbent article, the off-line produced web being manipulated as a controlled web in order for the pro-produced object of the controlled web to be registered in relation to a target position constant, the method comprising the steps of:

  • a. providing a controlled web having pre-produced objects spaced at a controlled pitch interval, at a controlled velocity in a machine direction, b. providing an actual position data of the pre-produced object on the controlled web moving in the machine direction by detecting the pre-produced object by a sensor within a manufacturing cycle of the pitched unit operation;

    c. providing the target position constant at a desired position within the manufacturing cycle of the pitched unit operation;

    d. generating a correction signal based upon the actual position data and the target position constant; and

    e. adjusting the control velocity of the control web in order to register the pre-produced object of the controlled web in relation to the target position constant wherein the correction signal is calculated according to a formula
    u=Kp*error+Ki

    error*Δ

    T whereinu is the correction signal, Kp is a proportional gain, Ki is a integral gain, error is an error signal, and Δ

    T is a time period between consecutive calculations.

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