Method for operating a treatment system, treatment system, and computer program product

Abstract

A disclosed method for operating a treatment system and to a treatment system for electrophoretic dip coating, more particularly dip painting of a metal workpiece, more particularly of a vehicle body, in a dipping tank filled with a paint, wherein: a relative movement between the workpiece and a bus bar is carried out in the dipping tank; a voltage is applied to the workpiece; and, while the workpiece is in the effective range of at least one bus bar portion of the bus bar, electric current is fed to the workpiece from the at least one bus bar portion at least some of the time. Examples disclosed herein also relate to a treatment system and to a computer program product.

1 . A method for operating a treatment plant for electrophoretic dip coating, in particular dip painting, of a metal workpiece, in particular a vehicle body, in a dip bath having a paint, the method comprising:
 causing relative movement between workpiece and a busbar in the dip bath,   applying an electrical voltage to the workpiece, and   supplying an electrical current to the workpiece by at least one busbar section during residence of the workpiece in the region of action of the at least one busbar section of the busbar.   
     
     
         2 . The method as defined in  claim 1 , further including regulating the electrical current supplied to the workpiece. 
     
     
         3 . The method as defined in  claim 1 , wherein the electrical voltage is applied to the workpiece by at least two electrically equivalent electrodes arranged in the dip bath in the region of action of the at least one busbar section,
 wherein at least one rectifier module is connected to at least one of the electrodes;   wherein the current supplied to the workpiece corresponds to a sum of partial current supplied by the individual rectifier modules, and   wherein a voltage setpoint value for the rectifier modules in the region of the workpiece to be coated is derived from a specified current setpoint value of the total current supplied to the workpiece and is specified to the individual rectifier modules.   
     
     
         4 . The method as defined  claim 3 , wherein an equal average voltage setpoint value is specified for the rectifier modules and the voltage at the rectifier modules is regulated so that ai specified total current is reached. 
     
     
         5 . The method as defined in  claim 4 , wherein for a plurality of busbar sections following one another in a feed direction, PID regulation is used for each busbar section, an average voltage of the respectively preceding busbar section being used as a start value for the PID regulation. 
     
     
         6 . The method as defined in  claim 4 , wherein a lower limit voltage and an upper limit voltage are specified for the current regulation. 
     
     
         7 . The method as defined in  claim 1 , wherein the treatment of the workpiece is carried out by charge quantity regulation, by regulating the current through the busbar section so that a specified charge setpoint value is reached. 
     
     
         8 . The method as defined in  claim 7 , wherein the current setpoint value for the charge quantity regulation is determined as a quotient of a charge quantity still required and a remaining treatment time. 
     
     
         9 . The method as defined in  claim 7 , wherein the charge setpoint value is adapted during the charge quantity regulation by adaptive regulation, the regulation being carried out as a function of treatment parameters, the regulation in particular being carried out as a function of at least one of the following parameters: paint parameters, in particular binder content of the paint, pigment content, solvent content, pH, conductivity or electrical conductivity of an electrolyte fluid, in particular an anolyte fluid, of the treatment. 
     
     
         10 . The method as defined in  claim 7 , wherein the charge setpoint value is adapted during the charge quantity regulation as a function of a measured thickness, deposited from the paint on the workpiece, of a coating, in particular a coating that includes paint particles. 
     
     
         11 . The method as defined in  claim 1 , wherein at a start of the treatment of the workpiece, the treatment is carried out by voltage regulation, by a setpoint voltage of rectifier modules being increased to a voltage setpoint value via an adjustable voltage ramp. 
     
     
         12 . The method as defined in  claim 1 , wherein the treatment of the workpiece is carried out over a specified time interval by voltage regulation, and is then carried out by current regulation coupled with charge quantity regulation until a specified charge setpoint value is reached. 
     
     
         13 . The method as defined in  claim 1 , wherein for controlled treatment of individual regions of the workpiece, voltage setpoint values of rectifier modules, which supply electrodes that are assigned to these regions along a feed direction, are adapted. 
     
     
         14 . A treatment plant for the electrophoretic dip coating, in particular dip painting, of a metal workpiece, in particular a vehicle body, in a dip bath filled with a paint, for carrying out a method as defined in  claim 1 , comprising at least
 at least two electrically equivalent electrodes, which in particular are arranged on both sides of the workpiece,   a busbar, which is arranged along a feed direction of the workpiece in the dip bath and is subdivided into individual busbar sections, the busbar being electrically connected to the workpiece, and   at least one current supply unit having at least one rectifier module, one pole of the at least one rectifier module being electrically connected to at least one of the at least two equivalent electrodes, and the other pole of the at least one rectifier module being electrically connected to the busbar, and the at least two equivalent electrodes applying an electrical voltage to the workpiece ( 40 ).   
     
     
         15 . The treatment plant as defined in  claim 14 , wherein the treatment plant is configured for current regulation of the electrical current supplied to the workpiece. 
     
     
         16 . The treatment plant as defined in  claim 14 , wherein the at least one current supply unit is configured to operate the rectifier modules respectively separately by voltage regulation. 
     
     
         17 . The treatment plant as defined in  claim 14 , wherein the at least one current supply unit is configured to operate the rectifier modules by current regulation coupled with charge quantity regulation by the current of a busbar section. 
     
     
         18 . The treatment plant as defined in  claim 14 , wherein the at least one current supply unit is configured to operate the rectifier modules in a first time interval by voltage regulation and in a second time interval by current regulation coupled with charge quantity regulation until a specified charge setpoint value is reached. 
     
     
         19 . A computer program product for carrying out the method according to  claim 1 , in order to operate a treatment plant for the electrophoretic dip coating, in particular dip painting, of a metal workpiece, in particular a vehicle body, in a dip bath filled with a paint, in which the workpiece is moved in a feed direction along a busbar and electrodes supplied by rectifier modules,
 comprising at least one computer-readable storage medium having program code instructions stored thereon, wherein an effect of the program code instructions which can be executed by a data processing system is that, during the residence of the workpiece in the region of action of at least one busbar section of the busbar, an electrical current is at least temporarily supplied to the workpiece by the at least one busbar section.   
     
     
         20 . The computer program product as defined in  claim 19 , wherein the effect of the program code instructions which can be executed by the data processing system is that,
 the treatment of the workpiece is carried out at least temporarily by current regulation, by a current setpoint value being specified for a busbar section of the busbar, an equal average voltage setpoint value being specified for the rectifier modules and the voltage being regulated so that a specified current threshold value is reached,
 and/or that the treatment of the workpiece is carried out by charge quantity regulation, by the current through the busbar section being supplied to the workpiece to reach a specified charge setpoint value; 
 and/or that the treatment of the workpiece is carried out over a first time interval by voltage regulation and in a second time interval by current regulation coupled with charge quantity regulation until a specified charge setpoint value is reached, 
 and/or that for controlled treatment of individual regions of the workpiece, voltage setpoint values of the rectifier modules, which supply the electrodes in these regions, are adapted.