Rolling mill third octave chatter control by process damping
AssigneeNovelis Inc.
InventorRodger Brown
Life of this patent
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Abstract
Control of third octave vibrations in a mill stand can be achieved using a high-speed piezoelectric assist coupled to a hydraulic gap cylinder to increase the damping of the roll stack. Vertical movements of the roll stack (e.g., the top work roll) can be determined through observation (e.g., measurement) of hydraulic fluid pressure of the hydraulic cylinder or entry tension of the metal strip. After determining vertical movements of the roll stack, a desired change in hydraulic pressure can be determined to overcome, reduce, or prevent third octave vibration. This desired change in hydraulic pressure can be effectuated at high speeds (e.g., at or above approximately 90 hertz) using the piezoelectric assist.
Claims20
A cold-rolling mill with reduced chatter, comprising:
- a mill stand having a top work roll and a bottom work roll between which a metal strip can be passed, the mill stand comprising a hydraulic cylinder mechanically coupled to provide rolling force to the top work roll;
- a piezoelectric assist coupled to the hydraulic cylinder for changing a volume of a fluid chamber of the hydraulic cylinder;
- and
- a controller coupled to a sensor selected from the group consisting of a pressure sensor of the hydraulic cylinder and a strip tension sensor, wherein the controller is further coupled to the piezoelectric assist for inducing changes in the volume of the fluid chamber in response to linear movement of the top work roll.
A method, comprising:
- passing a metal strip between a top work roll and a bottom work roll of a mill stand;
- applying a rolling force to the top work roll by a hydraulic cylinder;
- measuring a parameter of the mill stand, wherein the parameter is a hydraulic pressure of the hydraulic cylinder or an entry tension of the strip;
- determining vertical movement of the top work roll using the parameter;
- and
- actuating a piezoelectric assist to change a volume of the hydraulic cylinder in response to the vertical movement of the top work roll.
A method, comprising:
- passing a metal strip between a top work roll and a bottom work roll of a mill stand;
- applying a rolling force to the top work roll by a hydraulic cylinder having a volume of hydraulic fluid;
- determining vertical movement of the top work roll in a third octave range, wherein determining the vertical movement comprises calculating vertical movement based on a measurement of pressure of the hydraulic fluid or entry tension of the metal strip;
- calculating a desired change in the pressure of the hydraulic fluid;
- and
- applying force to the volume of hydraulic fluid based on the calculated desired change, wherein applying force to the volume of hydraulic fluid comprises actuating a piezoelectric actuator coupled to the hydraulic cylinder.
Dependencies are inferred from the claim text.