Electrode displacement monitoring and control
AssigneeEaton Corporation
InventorMichael L. Killian
Life of this patent
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Abstract
An electrode displacement monitoring and control system for predicting and adaptively controlling resistance weld quality. The distance (34) between the movable electrode (16) and a fixed point such as on a workpiece (12) surface is monitored during a resistance weld cycle. The displacement information is processed and applied as a control signal for dynamically and adaptively varying various weld parameters including current application in order to control weld quality. A reversal in the direction of electrode displacement is identified and used in the adaptive control strategy.
Claims16
In a resistance welding system wherein a workpiece is positioned with respect to an electrode which is movable axially toward and away from a given point which remains substantially fixed in position during a weld cycle, wherein an electronic weld controller controls the application of electrical current thereto, a method of adaptively controlling the application of electrical current comprising the steps of:
- positioning a sensor with respect to said welding system, said sensor being adapted to provide a series of discrete output signals each indicative of the instantaneous displacement of said movable electrode with respect to a point on said workpiece;
- electrically connecting a processor means between said sensor and said weld controller, said processor means being adapted to process said output signals from said sensor to produce a control signal to be applied to said weld controller;
- allocating a predetermined time for application of weld current by said controller for at least one of an expansion phase, a reversal phase and an indentation phase;
- identifying a reversal wherein said displacement signals cease increasing in magnitude and begin to decrease;
- and
- controlling the application of weld current in accordance with said control signal such that said displacement is controlled according to said predetermined time allocation.
In a resistance welding system wherein a workpiece is positioned with respect to an electrode which is movable axially toward and away from a given point which remains substantially fixed in position, wherein an electronic weld controller controls the application of electrical current to the electrodes, a method of adaptively controlling said weld controller comprising the steps of:
- positioning a sensor with respect to said welding system, said sensor being adapted to provide a series of discrete output signals each indicative of the instantaneous displacement of said movable electrode with respect to said workpiece;
- identifying a reversal wherein said displacements cease increasing in magnitude and begin to decrease;
- allocating a predetermined displacement value to at least one of an expansion prior to said reversal, said reversal or an indentation following said reversal;
- and
- modulating the current applied to said electrodes in a manner to achieve said predetermined displacement.
Dependencies are inferred from the claim text.