Method and system for registering pre-produced webs with variable pitch length
First Claim
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*Σ
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.
1 Assignment
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Accused Products
Abstract
A new machine control method and system for registering pro-produced webs into a converting line producing disposable absorbent articles such as diapers, pants, feminine hygiene articles or a component thereof. The pre-produced web can include a multiplicity of pre-produced objects spaced on the web at a pitch interval in the web direction. The pre-produced web being manipulated in order for the pre-produced object of the web to be registered in relation to a target position constant. The present invention includes three embodiments, where the first embodiment is expressed as a generic claim. The first embodiment includes a closed-loop feedback registration system; the second and third embodiments, in addition, include an open-loop feedforward phasing system. In addition, the third embodiment uses a machine vision system to recognize any element of a complex pre-produced object (e.g., colorful graphics).
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Citations
28 Claims
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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:
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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*Σ
error*Δ
Twherein u 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.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. 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 pre-produced object of the controlled web to be registered in relation to a target position constant and in phase automatically with the pitched unit operation, the method comprising the steps of:
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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 by detecting the pre-produced object by a sensor;
c. providing the target position constant at a desired position within a manufacturing cycle of a pitched unit operation;
d. generating a correction signal based upon the actual position data and the target position constant;
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; and
f. coupling the pitched unit operation with a controlled web metering point by providing a converter position reference signal fed forward from the pitched unit operation functioning as an independent axis to the controlled web metering point functioning as a dependent axis in order for the pre-produced object of the controlled web be in phase automatically with the pitched unit operation.
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27. 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 pre-produced object of the controlled web to be registered in relation to a target bias position constant and in phase automatically with the pitched unit operation, the method comprising the steps of:
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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 bias position data based upon the captured production images of the pre-produced objects of the controlled web and comparing the captured production images to one or more stored reference images by a machine vision system;
c. providing the target bias position constant at a desired position within a manufacturing cycle of the pitched unit operation;
d. generating a correction signal based upon the actual bias position data and the target bias position constant;
e. adjusting the controlled velocity of the controlled web in order to register the pre-produced object of the controlled web in relation to the target bias position constant; and
f. coupling the pitched unit operation with a controlled web metering point by providing a converter position reference signal fed forward from the pitched unit operation functioning as an independent axis to the controlled web metering point functioning as a dependent axis in order for the pre-produced object of the controlled web be in phase automatically with the pitched unit operation.
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28. A system 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 system comprising:
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a. a web metering point for providing a controlled web having pre-produced objects spaced at a controlled pitch interval moving in the machine direction at a controlled velocity in a machine direction, b. a sensor disposed adjacent the controlled web for providing an actual position data of the pre-produced object on the controlled web by detecting the pre-produced object within a manufacturing cycle of the pitched unit operation;
c. a product detection stage for providing the target position constant at a desired position within the manufacturing cycle of the pitched unit operation; and
d. a controller for generating a correction signal based upon the actual position data and the target position constant and for 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
μ
=Kp*error+Ki*Σ
error*Δ
Twherein μ
is the correction signal,Kp is a proportinal 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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Specification