Screwdown offset system and method for improved gauge control

Claim 3

The apparatus of claim 1, including computer means operative with said first rolling stand for providing mill spring curve information to be utilized in determining said calculated roll force delivery gauge for said first rolling stand.

Claim 4

The apparatus of claim 2, with said screwdown system being operative to adjust the roll opening of the rolling stand associated with said screwdown system, and with said recalibration offset being determined after the rolling of a given workpiece to provide unproved setup conditions for the rolling of a subsequent workpiece.

Claim 5

The apparatus of claim 2 operative within a roll force gauge control system for said first rolling stand to provide an online and updated screwdown offset for the latter roll force gauge control system during the rolling of a given workpiece.

Claim 6

The apparatus of claim 4, with said computer means including a control program for determining a predetermined validity status relative to said actual delivery gauge and said mass flow delivery gauge for said first rolling stand before providing an updated screwdown offset during the rolling of a given workpiece.

Claim 7

The apparatus of claim 2, with said computer means compensating for nonlinearity in the mill spring curve for determining a predicted gauge from said first rolling stand.

Claim 8

The apparatus of claim 2, with said computer means including a control program operative to effect a comparison between the actual mass flow delivery gauge and the calculated roll force delivery gauge for said first rolling stand and to provide an updated screwdown offset for said first rolling stand when said comparison falls within a predetermined validity range.

Claim 9

In apparatus for controlling a rolling mill having a plurality of rolling stands operative to reduce the thickness of a workpiece, said rolling mill having a screwdown system for each of said rolling stands, the combination of means responsive to the roll force of each rolling stand prior to the last of said rolling standings and responsive to the unloaded roll opening of that same rolling stand for determining a calculated roll force delivery gauge for each rolling stand prior to said last rolling stand means responsive to the actual delivery gauge and the operating speed of said last rolling stand and responsive to the operating speed of each rolling stand prior to said last stand for determining the mass flow delivery gauge for each rolling stand prior to said last rolling stand, and means responsive to the difference between said calculated roll force delivery gauge and said mass flow delivery for each rolling stand prior to said last rolling stand for determining a screwdown system recalibration offset for each rolliNg stand prior to said last rolling stand.

Claim 10

In apparatus for controlling a rolling mill having a plurality of rolling stands operative to reduce the thickness of a workpiece, said rolling mill having a screwdown system for each of said rolling stands, the combination of means responsive to the roll force of each rolling stand prior to the last of said rolling standings and responsive to the unloaded roll opening of that same rolling stand for determining a calculated roll force delivery gauge for each rolling stand prior to said last rolling stand means responsive to the actual delivery gauge and the operating speed of said last rolling stand and responsive to the operating speed of each rolling stand prior to said last stand for determining the mass flow delivery gauge for each rolling stand prior to said last rolling stand, and means responsive to the difference between said calculated roll force delivery gauge and said mass flow delivery for each rolling stand prior to said last rolling stand for determining a screwdown system recalibration offset for each rolliNg stand prior to said last rolling stand.

Claim 11

The apparatus of claim 8, including means for determining the average mass flow delivery gauge for at least one of said stands in relation to the number of said rolling stands that are operative to reduce the thickness of said workpiece.

Claim 12

The apparatus of claim 9, with the screwdown system for each rolling stand being operative to adjust the roll opening of the associated rolling stand, and including computer means operative with each of said rolling stands for providing mill spring curve information to be utilized in determining the calculated roll force delivery gauge for each of said rolling stands.

Claim 13

The apparatus of claim 10, with said computer means being included within a roll force gauge control system and providing online and updated screwdown offset for each of said rolling stands during the rolling of a given workpiece.

Claim 14

In a system for controlling a rolling mill having at least one rolling stand operative to reduce the thickness of a workpiece under the control of a roll force gauge control system, a screwdown recalibration system comprising the combination of: means for detecting the roll force at said rolling stand and for providing a roll force output signal representing the roll force detected at said stand; means for detecting the unloaded roll opening at said rolling stand and providing a position output signal corresponding to the unloaded roll opening of said stand; means for determining the actual workpiece gauge on the exit side of said rolling stand; means responsive to said roll force output signal and said position output signal for determining a calculated stand delivery gauge; means responsive to the difference between said calculated gauge and said actual workpiece gauge for effecting a screwdown offset factor for said rolling stand, said determining and effecting means include computer means operative to determine the calculated stand gauge from a stored mill spring curve and from the aforementioned roll force and position output signals, wherein said computer means includes a programming system which provides for using the initial offset factor in its entirety upon a change in mill setup to provide a screwdown offset and thereafter weighing further offset factors on the same setup according to a predetermined ratio with the previous offset factor to provide an updated screwdown offset.

Claim 15

In a system for controlling a rolling mill having at least one rolling stand operative to reduce the thickness of a workpiece under the control of a roll force gauge control system, a screwdown recalibration system comprising the combination of: means for detecting the roll force at said rolling stand and for providing a roll force output signal representing the roll force detected at said stand; means for detecting the unloaded roll opening at said rolling stand and providing a position output signal corresponding to the unloaded roll opening of said stand; means for determining the actual workpiece gauge on the exit side of said rolling stand; means responsive to said roll force output signal and said position output signal for determining a calculated stand delivery gauge; means responsive to the difference between said calculated gauge and said actual workpiece gauge for effecting a screwdown offset factor for said rolling stand, said determining and effecting means include computer means operative to determine the calculated stand gauge from a stored mill spring curve and from the aforementioned roll force and position output signals, wherein said computer means includes a programming system which provides for using the initial offset factor in its entirety upon a change in mill setup to provide a screwdown offset and thereafter weighing further offset factors on the same setup according to a predetermined ratio with the previous offset factor to provide an updated screwdown offset.

Claim 18

The method of claim 13, including the steps of establishing a validity range for said predetermined comparison between sad calculated roll force delivery gauge and said mass flow delivery gauge for at least said one earlier rolling stand, and adjusting said roll opening of at least said one earlier rolling stand in accordance with said comparison only when said comparison falls within said validity range.

Claim 19

The method of claim 13, including the step of establishing the rOll opening of at least said one earlier rolling stand in accordance with said offset factor for that same rolling stand, with said offset factor being utilized in its entirety upon a change in the setup of that same rolling stand and thereafter, weighing further established offset factors for that same rolling stand in accordance with a predetermined relationship with the previous offset factor to provide an updated offset factor.