CN219315120U - Treatment equipment for carrying out electrophoretic dip coating on metal workpiece - Google Patents
Treatment equipment for carrying out electrophoretic dip coating on metal workpiece Download PDFInfo
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- CN219315120U CN219315120U CN202221043753.7U CN202221043753U CN219315120U CN 219315120 U CN219315120 U CN 219315120U CN 202221043753 U CN202221043753 U CN 202221043753U CN 219315120 U CN219315120 U CN 219315120U
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- 239000002184 metal Substances 0.000 title claims abstract description 12
- 238000003618 dip coating Methods 0.000 title abstract description 25
- 239000003973 paint Substances 0.000 claims abstract description 25
- 238000007654 immersion Methods 0.000 claims abstract description 16
- 238000004070 electrodeposition Methods 0.000 claims abstract description 10
- 238000010422 painting Methods 0.000 claims description 15
- 230000033228 biological regulation Effects 0.000 description 78
- 238000000576 coating method Methods 0.000 description 62
- 239000011248 coating agent Substances 0.000 description 58
- 238000012545 processing Methods 0.000 description 50
- 238000000034 method Methods 0.000 description 45
- 230000000694 effects Effects 0.000 description 15
- 230000001105 regulatory effect Effects 0.000 description 14
- 210000000746 body region Anatomy 0.000 description 10
- 230000009286 beneficial effect Effects 0.000 description 9
- 239000010410 layer Substances 0.000 description 8
- 238000004590 computer program Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000012937 correction Methods 0.000 description 4
- 230000002950 deficient Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 238000002386 leaching Methods 0.000 description 4
- 230000003044 adaptive effect Effects 0.000 description 3
- 230000000284 resting effect Effects 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000001652 electrophoretic deposition Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000001962 electrophoresis Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000003232 water-soluble binding agent Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/22—Servicing or operating apparatus or multistep processes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/12—Electrophoretic coating characterised by the process characterised by the article coated
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/18—Electrophoretic coating characterised by the process using modulated, pulsed, or reversing current
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
The present application relates to a treatment device for the electrocoating of metal workpieces, wherein the treatment device (100) is used for the electrocoating of metal workpieces (40), in particular vehicle bodies, in an immersion bath (30) filled with paint, in particular for the dip coating, wherein a relative movement between the workpiece (40) and a current rail (21) is carried out in the immersion bath (30), wherein a voltage is applied to the workpiece (40), and wherein the workpiece (40) is supplied with current at least temporarily from at least one current rail section (22, 24, 26) while the workpiece (40) remains in the region of action of at least one current rail section (22, 24, 26) of the current rail (21).
Description
Technical Field
The present application relates to a method for operating a treatment device for the electrocoating of metal workpieces, in particular vehicle bodies, and to a treatment device and a computer program product for carrying out the method.
Background
The vehicle body is treated using an electrophoretic dip treatment device, such as a cathodic dip treatment device (KTL device), wherein the vehicle body is, for example, pretreated and/or lacquered by dipping it into a dipping bath for coating by means of electrophoresis. Electrophoretic deposition (EPD) is a widely used industrial process in which colloidal particles are deposited onto a workpiece as an electrode under the influence of an electric field. The workpiece (e.g., a vehicle body) is immersed in an electrically conductive aqueous dip coating and a dc voltage field is applied between the workpiece and the counter electrode. The basic principle of the electrophoretic dip coating is as follows: the water-soluble binder is precipitated on the surface of the workpiece connected as an electrode, and a closed adhesive paint film is thereby produced.
Disclosure of Invention
The object of the present application is to create a method for operating a treatment device for the electrocoating of metal workpieces, in particular vehicle bodies, by means of which a better coating effect can be achieved.
Another object is to create a treatment device for electrophoretic dip coating with which a better coating effect can be achieved.
Another object is to create a computer program product by means of which the improved method can be performed.
These objects are achieved by the features of the independent claims. Advantageous embodiments and advantages of the present application result from the other claims, the description and the figures.
The features recited individually in the claims can be combined with one another in a technically meaningful way and can be supplemented by explanatory facts from the description and by details from the drawings, in which further implementation variants of the application are indicated.
A method is proposed for operating a treatment device for the electrocoating, in particular dip-coating, of metal workpieces, in particular vehicle bodies, in a bath containing paint,
wherein a relative movement between the workpiece and the current rail is carried out in the immersion bath, wherein a voltage is applied to the workpiece, and wherein the workpiece is supplied with current at least temporarily from at least one current rail section while the workpiece is resting in the region of action of at least one current rail section of the current rail.
The current rail is subdivided into individual current rail sections. There is always only one body on each current rail section, wherein the length of each current rail section is smaller than the Taktabstand of the successive bodies.
The current flowing to each current rail is determined by a corresponding measuring device of the current supply unit. Thus, during processing, the workpieces are each arranged only in the region of the current rail section. The current rail sections may be longer or shorter than the workpieces, but are preferably always shorter than the beat spacing between the workpieces.
The electrodeposition dip coating may be a cathodic dip coating in which the work to be coated is turned on as a cathode, or an anodic dip coating in which the work to be coated is turned on as an anode. For cathodic dip coating, the electrode is filled with an anolyte as an electrolyte. For anodic dip coating, there is no need for any separate anolyte system as is required for cathodic dip coating.
According to one advantageous embodiment of the method, the current supplied to the workpiece can be regulated.
The current for current regulation can advantageously be determined in each current rail section. In the case of a current supply unit comprising a modular rectifier module, the current regulation also advantageously makes it possible to simply preset a desired coating current for each current rail section. Thus, a better painting effect can be achieved on the treated vehicle body.
According to one advantageous embodiment of the method, a voltage is applied to the workpiece via at least two electrically co-directional electrodes arranged in the immersion bath in the region of action of the at least one current rail section, wherein at least one rectifier module is connected to at least one of the electrodes, wherein the current supplied to the workpiece is the sum of the current components supplied by the individual rectifier modules, and wherein the voltage setpoint which is jointly adjusted for the individual rectifier modules in the region of the workpiece is derived from a preset current setpoint of the total current supplied to the workpiece, and the voltage setpoint is preset for the individual rectifier modules.
For the electro-dip coating, in particular dip coating, separate rectifying modules can be suitably used for the current supply of the electrically co-directional electrodes. For supplying direct current, each of these rectifier modules may be electrically connected to one electrode or to a set of electrodes, or a plurality of rectifier modules may be connected to a common electrode. By means of the modular construction, the voltage in the immersion bath can be controlled or regulated very precisely.
In a vehicle body treatment section, which also corresponds to a current rail section, a plurality of electrodes are generally used, which can be arranged on both sides of the vehicle body in order to achieve a beneficial treatment effect. Typically, ten to sixteen electrodes may be preset for flat or semicircular electrodes. In the case of circular electrodes, up to forty electrodes may be preset. Of course, more or fewer electrodes may be preset depending on the device.
All the rectifier modules have a common pole, a common negative pole in the case of cathodic coating and a common positive pole in the case of anodic coating, which are connected to the vehicle body via a current rail comprising a single current rail section.
Advantageously, the total current for processing the vehicle body, which is formed by the sum of the individual current component values of the at least one electrode and the at least one rectifier module supplying it, can be preset and regulated thereby. In particular, for a plurality of rectifier modules, they can be controlled and/or regulated independently of one another. In this way, the operating mode of the processing unit for the power-on can be set and switched in an advantageous manner.
According to one advantageous embodiment of the method, the same average voltage setpoint value is preset for the rectifier modules, and the voltage across the rectifier modules is adjusted to achieve the respectively preset total current setpoint value.
The vehicle body is connected to a common pole of the rectifier module via a current rail. The passing current to the current rail is measured and corresponds to the current consumption of the vehicle body. Switching from voltage regulation to current regulation. For example, the average voltage of all electrodes within the body region (excluding the processed start-up and follow-up sections) can be calculated in a programmable logic controller program of the control unit and assigned to the current rail section currently occupied.
During current regulation, all electrodes in the process zone (including the start-up and follow-up sections) remain at the same voltage rating. The voltage is adjusted to achieve the desired current rating.
In this case, the voltage can be varied between two nominal values, namely between the lowest voltage of the current regulation and the highest voltage of the current regulation.
According to one advantageous embodiment of the method, for a plurality of current rail sections arranged one after the other in the conveying direction, a proportional-integral-derivative control (PID-reglung) can be applied for each current rail section, wherein the average voltage of the respectively preceding current rail section is used as an initial value for the proportional-integral-derivative control.
Thus, a separate proportional-integral-derivative control can be applied for each current rail section and matched as needed. For example, the average voltage of the preceding current rail section can always be set as an initial value for the regulation, the so-called Y compensation value. In this way, a constant regulation of the voltage over the entire conveying path can be ensured and voltage jumps can be avoided.
During leaching of the vehicle body from the paint of the bath, the current regulation is stopped and the electrode retains its current voltage or is applied with a specific leaching voltage.
According to one advantageous embodiment of the method, a lower limit voltage and an upper limit voltage are predefined for the current regulation. Thus, during the current regulation, the voltage may vary between two nominal values, namely between the lowest voltage of the current regulation and the highest voltage of the current regulation. The voltage is preset and the current component varies between 0A and the highest possible current component for each rectifying module. At the start of the coating, the voltage is increased from 0V to the desired setpoint value by a settable ramp.
According to one advantageous embodiment of the method, the workpiece is processed by adjusting the current flowing through the current rail section to a predetermined charge setpoint value, thereby controlling the amount of charge.
Since the coating particles to be deposited, in particular paint particles, are coated by means of galvanic transport, the total charge quantity is a measure of the coating thickness of the deposited coating material (e.g. deposited paint).
Advantageously, the charge amount adjustment may be such that the same amount of charge, i.e. the amount of coating material from the paint, is deposited on each vehicle body at all times. For example, fluctuations in the coating temperature can be automatically equalized by the charge control device, so that all vehicle bodies that are coated, in particular painted, have a beneficial coating effect. In this way, paint consumption and paint quality can be optimized.
The charge quantity adjustment can advantageously be activated from a settable coating time. For this purpose, the amount of charge missing to achieve the desired charge setpoint value and the remaining coating time until the vehicle body begins to leach out of the coating can be determined, for example.
Advantageously, the amount of charge released by the rectifier module during painting can thus be kept constant. Thereby, it is ensured that a beneficial painting effect is ensured for all vehicle bodies.
By means of charge control, the coating thickness can be optimized and kept constant. In this way, material costs can be saved and quality problems due to defective coating can be avoided during the coating process.
According to an advantageous embodiment of the method, the current setpoint for the charge quantity regulation can be determined as the quotient of the missing charge quantity and the remaining processing time.
Once the charge amount adjustment is activated, the coating current is adjusted. The current rating is continuously calculated to achieve the desired charge amount:
current rating = delta charge/delta time,
or desired units on the tape:
current rating [ a ] =missing charge amount [ Amin ] ×60/residual coating time [ s ]
If charge control is activated, the total current flowing through the vehicle body is controlled to the calculated setpoint value. The voltage automatically varies between a settable minimum and maximum value.
At the end of the coating, the charge reached is checked and compared with a preset limit value. If the limit is exceeded or undershot, a corresponding warning message or fault message may be issued.
According to one advantageous embodiment of the method, the charge setpoint in the charge amount adjustment process can be adapted by means of an adaptive adjustment, wherein the adjustment is performed as a function of the process parameters. In particular, the adjustment may be effected according to at least one of the following parameters of the process: coating parameters, in particular binder content, pigment content, solvent content, pH value, conductivity of the electrolyte, in particular of the anolyte. For cathodic dip coating, the electrode is filled with an anolyte. For anodic dip coating, acid is generated on the workpiece and no separate anolyte system is required as required for cathodic dip coating.
In a further step, additional parameters may be taken into account. For this purpose, an adaptive adjustment can be used, which automatically adapts the charge setpoint of the vehicle body by means of external process parameters.
The external parameters may mainly be coating parameters such as binder content, pigment content, solvent content, pH value, conductivity and conductivity of the electrolyte, in particular of the anolyte. The correlation between these external parameters and the charge consumption can be stored, for example, in a mathematical formula in a programmable logic controller program of a control unit of the current supply unit.
If, for example, the pH of the coating is above the nominal value, the charge nominal value can be lowered by a specific charge value. If, on the other hand, the pH of the coating is below the nominal value, the charge nominal value can be increased by a specific amount.
According to an advantageous embodiment of the method, the charge setpoint in the charge control process can be adapted as a function of the measured thickness of the coating deposited from the coating onto the workpiece, in particular the thickness of the coating comprising the coating particles.
Alternatively, the layer thickness of each body can be determined automatically by means of layer thickness measurement after the electrocoating. If the layer thickness is too high, the charge rating is automatically reduced. If the layer thickness is too low, the charge rating is automatically increased.
According to one advantageous embodiment of the method, the nominal voltage of the rectifier module is increased to a nominal voltage value via a settable voltage ramp at the beginning of the processing of the workpiece, so that the processing takes place by means of voltage regulation.
In this way, the starting current, which rises very steeply at the beginning of the process, can advantageously be adjusted. As the thickness of the coating increases, the current decreases as the insulation of the applied coating (particularly paint) increases. This value can advantageously be set higher than the voltage rating.
According to one advantageous embodiment of the method, the workpiece can be processed by means of voltage regulation during a predetermined time interval and subsequently by means of current regulation in combination with charge quantity regulation until a predetermined charge setpoint value is reached.
By means of this regulation strategy, a relatively rapid coating with a first coating thickness can advantageously be achieved by voltage regulation, after which the coating can be continued by subsequent charge regulation until the desired coating thickness is reached.
According to one advantageous embodiment of the method, in order to specifically treat individual regions of the workpiece, the voltage setpoint value of the rectifier module can be adapted, which supplies the electrodes assigned to these regions in the conveying direction.
By virtue of the modular design of the current supply unit comprising the individual rectifier modules, individual body regions can be influenced in a targeted manner. For this purpose, the voltage in a specific body region is increased or decreased in order to influence the layer thickness, for example, by means of a maximum voltage adaptation of ±20%.
In this case, the body region can expediently always be greater than the distance between the two electrodes. For this mode of operation, it is advantageous if the electrodes are small (such as circular electrodes) and as many rectifying modules as possible, whereby the immersion bath can be subdivided into a plurality of small voltage areas.
According to a further aspect of the present application, a treatment device is proposed for the electrocoating, in particular dip-coating, of metal workpieces, in particular vehicle bodies, in a dip bath filled with paint, in order to carry out the method as described hereinbefore.
The processing device comprises at least: at least two electrically co-directional electrodes, which are arranged in particular on both sides of the workpiece; a current rail which is arranged in the immersion bath along the conveying direction of the workpiece and is subdivided into individual current rail sections, wherein the current rail is electrically connected to the workpiece; and at least one current supply unit comprising at least one rectifying module, wherein a pole of the at least one rectifying module is electrically connected to at least one of the at least two co-directional electrodes, and wherein another pole of the at least one rectifying module is electrically connected to the current rail, and the at least two electrically co-directional electrodes apply a voltage to the workpiece.
The current rail is subdivided into individual current rail sections. During the process, only one workpiece, for example a vehicle body, is provided on each current rail section, wherein the length of each current rail section is smaller than the pitch of the vehicle bodies arranged in sequence. The current flowing to each current rail is determined by a corresponding measuring device of the current supply unit. During processing, the workpieces are therefore each arranged only in the region of the current rail section that is shorter than the beat distance.
According to an advantageous embodiment of the treatment device, the treatment device can be designed for current regulation of the current supplied to the workpiece.
For current regulation within each current rail section, a current is determined. In the case of a current supply unit comprising a modular rectifier module, the current regulation also advantageously makes it possible to simply preset the desired coating current for each current rail section. Thus, a better painting effect can be achieved on the treated vehicle body.
According to one advantageous embodiment of the processing device, the at least one current supply unit can be designed as: the rectifier modules are each operated individually by means of voltage regulation.
The vehicle body is connected to a common pole of the rectifier module via a current rail. The current flow to the current rail is measured and corresponds to the current consumption of the vehicle body. Switching from voltage regulation to current regulation. For example, the average voltage of all electrodes within the body region (excluding the start-up and follow-up sections of the process) can be calculated in a programmable logic controller program of the control unit and assigned to the current rail currently occupied.
During current regulation, all electrodes in the process zone (including the start-up and follow-up sections) remain at the same voltage rating. The voltage is adjusted to achieve the desired current rating.
In this case, the voltage can be varied between two nominal values, namely between the lowest voltage of the current regulation and the highest voltage of the current regulation.
According to one advantageous embodiment of the processing device, the at least one current supply unit can be designed as: the rectifier module is operated by means of current regulation in combination with charge regulation, through the current of the current rail section.
Since the coated particles from the paint are applied by means of galvanic transport, the total charge quantity represents the size of the coating thickness of the applied coating (in particular of the coating comprising the paint particles).
Advantageously, the charge amount adjustment can ensure that the same charge amount is always deposited for each vehicle body. For example, fluctuations in the paint temperature can be compensated automatically by the charge control device, so that all vehicle bodies to be painted have a beneficial painting effect. In this way, paint consumption and paint quality can be optimized.
According to one advantageous embodiment of the processing device, at least one of the current supply units may be designed as: in a first time interval, the rectifier module is operated by means of voltage regulation, and in a second time interval, the rectifier module is operated by means of charge quantity regulation combined with current regulation until a preset charge rating is reached.
The charge amount adjustment can be appropriately activated from the settable coating timing. For this purpose, it is possible, for example, to determine the charge that is missing in order to achieve the desired charge setpoint and the remaining application time until the vehicle body begins to leach out of the coating of the immersion bath.
Advantageously, the amount of charge released by the rectifier module during painting can thus be kept constant. Thereby, it is ensured that a beneficial painting effect is ensured for all vehicle bodies.
By means of charge quantity regulation, the deposited layer thickness can be optimized and kept constant. In this way, material costs can be saved and quality problems due to defective coating can be avoided during the coating process.
By means of this regulation strategy, a relatively rapid coating with a first coating thickness can advantageously be achieved by voltage regulation, after which the coating can be continued by subsequent charge measurement until the desired coating thickness is reached.
According to a further aspect of the present application, a computer program product is proposed for carrying out the method according to the present application for operating a treatment device for the electrocoating, in particular dip-coating, of a metal workpiece, in particular a vehicle body, in a bath filled with paint, wherein the workpiece is moved in a transport direction along a current rail and an electrode supplied by a rectifier module. The computer program product comprises: at least one computer-readable storage medium having program code instructions stored thereon, wherein the program code instructions executable by the data processing apparatus cause: when the workpiece is in the active region of at least one current rail section of the current rail, the workpiece is supplied with current at least temporarily from the at least one current rail section.
According to an advantageous design of the computer program product, the program code instructions implementable by the data processing device may cause: processing of the workpiece by presetting a current setpoint value for a current rail section of the current rail, at least temporarily by means of current regulation, wherein the same, regulated voltage setpoint value is preset for the rectifier module, and the voltage is regulated to achieve the preset current setpoint value; and/or processing the workpiece by means of charge amount adjustment by adjusting the current flowing through the current rail section to reach a preset charge rating; and/or in a first time interval, processing the workpiece by means of voltage regulation, and in a second time interval, processing the workpiece by means of charge quantity regulation combined with current regulation until a preset charge rating is reached; and/or to specifically process individual regions of the workpiece, the voltage ratings of the rectifier modules supplying the electrodes in these regions are matched.
Advantageously, the total current for processing the vehicle body, which is formed by the sum of the individual current component values of the individual electrodes and the rectifier modules supplying them, can thereby be preset and regulated, wherein the individual current component values are controlled independently of one another.
In this way, the operating mode of the processing unit for the power-on can be set and switched in an advantageous manner.
Advantageously, the amount of charge released by the rectifier module during painting can thus be kept constant. Thereby, it is ensured that a beneficial painting effect is ensured for all vehicle bodies.
By means of charge quantity regulation, the deposited layer thickness can be optimized and kept constant. In this way, material costs can be saved and quality problems due to defective coating can be avoided during the coating process.
Drawings
Other advantages are derived from the following description of the drawings. Embodiments of the present application are illustrated in the accompanying drawings. The figures, description and claims contain a number of combined features. Those skilled in the art will also suitably review the features individually and combine them into useful other combinations.
The figures show by way of example:
FIG. 1 illustrates one embodiment of the present application including a processing device;
FIG. 2 shows a schematic diagram of a processing device including example values of current regulation according to one embodiment of the present application;
FIG. 3 illustrates a schematic diagram of a processing apparatus including example values for rating matching in a voltage adjustment process for weighting individual workpiece areas according to one embodiment of the present application;
FIG. 4 illustrates a schematic diagram of a processing apparatus including example values for rating matching in a current adjustment process for weighting individual workpiece areas according to one embodiment of the present application; and is also provided with
Fig. 5 shows a typical voltage/current profile during a treatment in a charge-regulated mode of operation of the method according to an embodiment of the present application.
Detailed Description
The drawings are only illustrative and should not be taken as limiting.
Before the present application is described in detail, it is to be noted that it is not limited to the respective components of the apparatus and the respective method steps as such components and methods may vary. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Furthermore, if a singular or indefinite article is used in the specification or in the claims, it is referred to a plurality of that element unless explicitly stated to the contrary.
Directional terminology used hereinafter, with concepts such as "left", "right", "upper", "lower", "front", "rear", etc., is used for a better understanding of the figures only and is not intended to be limiting in any way. The components and elements shown, as well as their design and use, may all be varied under the trade-off of those skilled in the art and may be adapted to the respective application.
Fig. 1 illustrates one embodiment of the present application including a processing device 100.
The treatment device 100 for the electrophoretic (e.g. cathodic) dip-coating of metal workpieces 40, in particular vehicle bodies, in a bath 30 filled with paint comprises a plurality of electrodes 32, in particular arranged on both sides of the workpiece 40. The relative movement between the workpiece 40 and the current rail 21 takes place in the immersion bath 30, i.e. for a fixed current rail 21, the workpiece in the immersion bath 30 is moved between the likewise fixed electrodes 32 in the conveying direction 42.
For cathodic dip coating, the workpiece 40 to be coated is turned on as a cathode, and the electrode is filled with an anolyte.
Further, the treatment device 100 comprises a current rail 21 which is arranged in the immersion bath 30 along the transport direction 42 of the workpiece 40 and which is subdivided into individual current rail sections 22, 24, 26. The length 46 of the current rail sections 22, 24, 26 can be matched to the length 44 of the workpiece 40 in the conveying direction 42. The current rail sections 22, 24, 26 may be as long as the workpiece 40, but may also be longer or shorter, but are preferably always shorter than the beat intervals.
The current rail 21 is electrically connected to the workpiece 40, for example, by a cable. However, this is not shown in fig. 1.
Only one vehicle body is always present on each current rail section 22, 24, 26, the length of each current rail section 22, 24, 26 being smaller than the pitch of the vehicle bodies arranged one behind the other. The current flowing to each current rail section 22, 24, 26 is determined by the corresponding measuring device 18 of the current supply unit 10. Thus, during processing, the workpieces 40 are each arranged only in the region of the current rail sections 22, 24, 26, for example, which corresponds to the length of the workpiece 40. The current is determined for current regulation within each current rail section 22, 24, 26.
In the case of a current supply unit 10 comprising a modular rectifier module 12, the current regulation also advantageously makes it possible to simply preset the desired coating current for each current rail section 22, 24, 26. Thus, a better painting effect can be achieved on the treated vehicle body.
For the electro dip coating, separate rectifying modules 12 may be suitably used for the current supply of the electrodes 32, respectively. Each of these rectifier modules 12 supplies direct current to one electrode 32 or a group of electrodes 32. By the modular construction, the voltage in the immersion bath 30 can be controlled very precisely. Alternatively, a plurality of rectifying modules 12 may be provided for one electrode 32.
In the body treatment section, which also corresponds to the current rail sections 22, 24, 26, typically ten to sixteen flat or semicircular electrodes 32 are used, respectively, which can be arranged on both sides of the body in order to achieve a beneficial treatment effect. In the case of circular electrodes 32, more electrodes, for example up to forty electrodes, may also be preset. More or fewer electrodes may also be preset, respectively.
All the rectifier modules 12 have a common pole 16, which is connected to the vehicle body via a current rail 21 having individual current rail sections 22, 24, 26. For cathodic dip coating, the common electrode 16 is the negative electrode, while for anodic dip coating, the common electrode 16 would be the positive electrode.
Advantageously, the total current for processing the vehicle body, which is formed by the sum of the individual electrodes 32 and the individual current component values 75 of the rectifier module 12 supplying them, can thus be preset and regulated, wherein the control is carried out independently of one another. Thereby, the operation mode of the energization of the processing unit 100 can be set and switched advantageously.
In the embodiment in fig. 1, two current supply units 10 have a plurality of rectifying modules 12. In this case, the positive electrodes 14 of the rectifier modules 12 are each electrically connected to at least one electrode 32. The cathodes 16 of all the rectifying modules 12 are electrically connected to the current rail 21. Thus, a voltage can be applied to the workpiece 40 through the electrodes 32 disposed on both sides of the workpiece 40 in the coating of the immersion bath 30.
During processing, the workpieces 40 are each arranged only in the region of one current rail section 22, 24, 26.
The processing apparatus 100 is designed to current regulate the current supplied to the workpiece 40. The current can be determined individually by the current measuring unit 18 in each current rail section 22, 24, 26. The negative pole 16 of the rectifier module 12 is electrically connected to the current rail sections 22, 24, 26 via the current measuring unit 18 and optionally via a coupling thyristor 28.
The rectifier modules 12 can each be operated individually by means of voltage regulation by means of the current supply unit 10.
The current through the current rail sections 22, 24, 26 can be adjusted by means of current regulation in combination with charge quantity regulation, operating the rectifier module 12.
The current supply unit 10 is designed to: during a first time interval, the rectifier module 12 is operated by means of voltage regulation, and during a second time interval, the rectifier module is operated by means of charge amount regulation combined with current regulation until a preset charge rating 80 is reached.
According to the method according to the present application, the adjustment of the current supplied by the at least one current rail section 22, 24, 26 to the workpiece 40 is performed at least temporarily while the workpiece 40 is resting in the region of action of the at least one current rail section 22, 24, 26 of the current rail 21.
The current supplied to the workpiece 40 is the sum of the current components supplied by the individual rectifier modules 12, wherein the voltage setpoint 71 for the rectifier modules 12 in the region of the workpiece 40 to be coated is derived from the preset current setpoint of the total current supplied to the workpiece 40, and the voltage setpoint is preset for the individual rectifier modules 12.
The same average voltage setpoint 71 (shown in fig. 2) can be preset for the rectifier module 12, and the voltage across the rectifier module 12 is adjusted to achieve the respectively preset total current of the workpieces 40.
For a plurality of current rail sections 22, 24, 26 arranged one after the other in the conveying direction 42, for example, a proportional-integral-derivative control can be applied for each current rail section 22, 24, 26, wherein the average voltage of the respectively preceding current rail section 22, 24, 26 can be used as an initial value for the proportional-integral-derivative control.
Suitably, a lower limit voltage and an upper limit voltage may be preset for the current regulation.
Thus, separate proportional-integral-derivative controls may be used for each current rail section 22, 24, 26. For example, the average voltage of the preceding current rail section 22, 24, 26 can always be set as an initial value for the regulation, the so-called Y compensation value. In this way, it is ensured that the voltage is regulated constantly over the entire conveying path and no voltage jumps occur.
During the leaching of the vehicle body from the paint, the current regulation is stopped and the electrode 32 either retains its present voltage or has a dedicated leaching voltage applied.
The vehicle body is connected to the common cathode 16 of the rectifier module 12 via a current rail 21. The current flow to the current rail 21 is measured and corresponds to the current consumption of the vehicle body. Switching from voltage regulation to current regulation. For example, the average voltage of all electrodes 32 within the body region (excluding the processed start and follow-up sections) can be calculated in a programmable logic controller program of the control unit and distributed to the current rail sections 22, 24, 26 currently occupied.
During the current regulation, all electrodes 32 in the process zone (including the start-up and follow-up sections) remain at the same voltage rating 71. The voltage is adjusted to achieve the desired current rating.
In this case, the voltage 70 may vary between two nominal values, namely between the lowest voltage of the current regulation and the highest voltage of the current regulation.
Fig. 2 shows a schematic diagram of a processing device 100 according to an embodiment of the present application, including example values of current regulation. In a schematic longitudinal section, a processing device 100 is shown, wherein the individual electrodes 32 are shown as vertical checkered rectangles. The transport unit 34 is arranged on a support body 36 and supports a vehicle body as a workpiece 40, which is immersed head-down into the immersion bath 30. The workpiece 40 is moved in a conveying direction 42, which is indicated by an arrow.
A start section area 52 and a follow section area 50 and a body area 54 of the treatment device are marked.
During the current regulation by the voltage values and the current values for the respective electrode pairs of the electrodes 32 arranged on both sides of the workpiece 40, all the electrodes 32 maintain the same voltage value 70 as the rated voltage. In this case, the voltage 70 is adjusted such that the desired total current 74 is produced on the current rail 21. In the embodiment shown, a current rating of 700A is preset, which results from the sum of the individual current values 75 of the electrodes 32.
A schematic diagram of a processing apparatus 100 according to one embodiment of the present application is shown in fig. 3, including example values for rating matching during voltage adjustment for weighting individual workpiece areas 56, 58, 60.
In order to specifically process individual regions 56, 58, 60 of workpiece 40, voltage setpoint values 71 of rectifier modules 12 are adapted, which supply electrodes 32 assigned to these regions 56, 58, 60 in transport direction 42.
By virtue of the modular design of the current supply unit 10 comprising the individual rectifier modules 12, individual body regions 56, 58, 60 can be influenced in a targeted manner. For this purpose, the voltage in the specific body region 56, 58, 60 is increased or decreased in order to influence the layer thickness, for example, by a maximum voltage adaptation of ±20%.
In this case, the body regions 56, 58, 60 can expediently always be greater than the distance between the two electrodes. For this mode of operation, it is advantageous if the miniature electrodes 32 (such as circular electrodes) and as many rectifier modules 12 as possible, the immersion bath 30 can thus be subdivided into a plurality of small voltage regions.
For this purpose, the voltage setpoint 71 assigned to the electrodes 32 of the regions 56, 58, 60 can be corrected by a correction value 73 for voltage matching, by which a matching voltage setpoint 72 is then determined. By means of these matched voltage nominal values 72, the processing of the workpiece 40 can be continued and the individual regions 56, 58, 60 can be processed specifically with higher or lower deposition rates of the coating to be applied.
In fig. 3, individual regions 56, 58, 60 are provided with factors of-10% to +10%, which are used to weight the corresponding voltage nominal values 71 and thus to determine a matched voltage nominal value 72.
Fig. 4 shows a schematic diagram of a processing apparatus 100 according to one embodiment of the present application, including example values for rating matching during current adjustment for weighting individual workpiece areas 56, 58, 60.
The correction value 73 that is the same as the example in fig. 3 is the basis thereof. However, in this case, instead of the voltage nominal value 71 of the voltage regulation, the voltage nominal value 71 is matched in the current regulation. In this case, the voltage values for the individual electrodes 32 are preset by means of current regulation and are adapted to produce the desired total current.
The voltage nominal value 71 shown in fig. 4, which is the value xxx V, comes from the current regulation. These values 71 are correspondingly matched by correction values 73. The current component 75 thus achieved is listed by way of example, and it yields a preset current rating of 480A.
Fig. 5 shows a typical voltage/current profile during a process in a process plant 100 as shown in fig. 1 in a charge-regulated mode of operation of the method according to an embodiment of the present application.
Advantageously, charge amount adjustment may ensure that the same charge amount 76 is deposited for each vehicle body at all times. For example, fluctuations in the paint temperature can be compensated automatically by the charge control device, so that all painted vehicle bodies have a beneficial painting effect. In this way, paint consumption and paint quality can be optimized.
The charge amount adjustment can be appropriately activated from the settable coating time 82. For this purpose, for example, the amount of charge Δq that is missing in order to achieve the desired charge setpoint value 80 and the remaining application time Δt until the vehicle body begins to leach out of the paint can be determined.
Advantageously, the amount of charge 76 released by the rectifier module 12 during painting can thus be kept constant. Thereby, it is ensured that a beneficial painting effect is ensured for all vehicle bodies.
By means of charge control, the coating layer thickness can be optimized and kept constant. In this way, material costs can be saved and quality problems due to defective coating can be avoided during the coating process.
According to one advantageous embodiment of the method, the current setpoint for the charge quantity regulation is determined as the quotient of the missing charge quantity Δq and the remaining processing time Δt.
The voltage 70, the resulting current 74 and the charge 76 are plotted in fig. 5 as a function of time 84 during processing in the processing apparatus 100.
First, the rectifier module 12 and the electrode 32 operated by it are operated in a voltage-regulated manner until a time 82 when a charge regulation takes place.
At the beginning of the processing of the workpiece 40, the voltage control is performed by increasing the nominal voltage of the rectifier module 12 to the voltage nominal value 71 via a settable voltage ramp.
During a predetermined time interval, the processing of the workpiece 40 takes place by means of voltage regulation, and subsequently by means of charge quantity regulation combined with current regulation until a predetermined charge setpoint value 80 is reached.
During the voltage regulation phase, the current 74 increases first abruptly, while the voltage 70 increases moderately. Subsequently, the current 74 again drops to the average value, because of the insulating effect of the deposited coating on the workpiece 40.
Since the time 82 when the switch is made to charge control, the rectifier module 12 is operated current-controlled in accordance with the determined charge quantity Δq still missing from the charge setpoint 80, which is to be reached within the still available time Δt. The charge 76 thus rises linearly over this section up to a charge setpoint 80.
The processing of the workpiece 40 takes place by means of charge quantity regulation by regulating the current flowing through the current rail sections 22, 24, 26 to reach a preset charge setpoint 80.
The current rating for charge amount adjustment is determined as the quotient of the missing charge amount and the remaining processing time.
Advantageously, the charge setpoint 80 during charge amount adjustment can be matched by means of adaptive adjustment. For example, the adjustment may be implemented according to processing parameters. In particular, the adjustment may be effected according to at least one of the following parameters of the process: coating parameters, in particular solvent content, pH, conductivity and conductivity of the electrolyte, in particular of the anolyte.
The charge rating 80 during charge amount adjustment may also be matched, for example, based on the measured thickness of the coating deposited from the coating onto the workpiece 40, particularly the thickness of the coating comprising the coating particles.
Advantageously, the current supply unit 10 of the processing device 100 is connected to a computer, which executes a computer program product for executing the method according to the present application for operating the processing device 100 for the electrophoretic (e.g. cathodic) dip painting of a metal workpiece 40, in particular a vehicle body, in a bath 30 filled with paint, wherein the workpiece 40 is moved in a conveying direction 42 along the current rail 21 and the electrode 32 supplied by the rectifying module 12, the computer program product comprising at least one computer readable storage medium on which program code instructions are stored, wherein the program code instructions executable by the data processing device cause: when the workpiece 40 is resting in the region of action of the at least one current rail section 22, 24, 26 of the current rail 21, the workpiece 40 is supplied with current at least temporarily by the at least one current rail section 22, 24, 26.
Further, the program code instructions may advantageously cause: the processing of the workpiece 40 takes place at least temporarily by means of a current regulation by presetting a current setpoint for the current rail sections 22, 24, 26 of the current rail 21, wherein the same average voltage setpoint 71 is preset for the rectifier module 12 and the voltage is regulated to reach the preset current setpoint; and/or by adjusting the current flowing through the current rail sections 22, 24, 26 to reach a preset charge rating 80, whereby the processing of the workpiece 40 is performed by means of charge amount adjustment; and/or during a first time interval, the processing of the workpiece 40 is performed by means of voltage regulation, and during a second time interval, the processing of the workpiece is performed by means of charge quantity regulation combined with current regulation until a preset charge rating 80 is reached; and/or to specifically process individual regions 56, 58, 60 of the workpiece 40, the voltage setpoint 71 of the rectifier module 12 supplying the electrodes 32 in these regions 56, 58, 60 is adapted.
Reference numerals
10. Current supply unit
12. Rectifying module
14. Positive electrode
16. Negative electrode
18. Current measuring unit
20. Connecting wire
21. Current rail
22. Current rail section
24. Current rail section
26. Current rail section
28. Coupled thyristor
30. Bath tank
32. Electrode
34. Transport unit
36. Support body
40. Workpiece
42. Direction of conveyance
44. Workpiece length
46. Length of current rail
50. Follow-up section
52. Starting section
54. Body region
56. Zone 1
58. Zone 2
60. Zone 3
70. Voltage (V)
71. Voltage rating
72. Matched voltage rating
73. Correction value
74. Electric current
75. Current component
76. Electric charge
80. Charge rating
82. Charge amount adjustment starts
84. Time of
100. A processing device.
Claims (1)
1. A treatment plant, characterized in that the treatment plant (100) is used for the electrocoating, in particular dip-painting, of metal workpieces (40), in particular vehicle bodies, in a bath (30) filled with paint, comprising at least:
at least two electrically co-directional electrodes (32), which are arranged in particular on both sides of the workpiece (40),
-a current rail (21) which is arranged in the immersion bath (30) along a transport direction (42) of the workpiece (40) and which is subdivided into individual current rail sections (22, 24, 26), wherein the current rail (21) is electrically connected to the workpiece (40),
at least one current supply unit (10) comprising at least one rectifying module (12), wherein a pole of at least one of the rectifying modules (12) is electrically connected to at least one of at least two co-directional electrodes (32), and wherein another pole of at least one of the rectifying modules (12) is electrically connected to the current rail (21), and at least two co-directional electrodes (32) apply a voltage to the workpiece (40), wherein the co-directional electrodes (32) are supplied with current by separate rectifying modules (12), respectively, each of the rectifying modules (12) being electrically connected to one electrode (32) or to a group of electrodes (32), or a plurality of rectifying modules (12) being connected to a common electrode (32).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102021111415.2 | 2021-05-03 | ||
| DE102021111415.2A DE102021111415A1 (en) | 2021-05-03 | 2021-05-03 | METHOD OF OPERATING A TREATMENT PLANT AND TREATMENT PLANT AND COMPUTER PROGRAM PRODUCT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219315120U true CN219315120U (en) | 2023-07-07 |
Family
ID=81598035
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221043753.7U Active CN219315120U (en) | 2021-05-03 | 2022-04-29 | Treatment equipment for carrying out electrophoretic dip coating on metal workpiece |
| CN202210473299.7A Pending CN115287733A (en) | 2021-05-03 | 2022-04-29 | Method for operating a processing device, processing device and computer program product |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210473299.7A Pending CN115287733A (en) | 2021-05-03 | 2022-04-29 | Method for operating a processing device, processing device and computer program product |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20240141539A1 (en) |
| EP (1) | EP4334512A1 (en) |
| CN (2) | CN219315120U (en) |
| DE (2) | DE102021111415A1 (en) |
| WO (1) | WO2022233362A1 (en) |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2935061C2 (en) | 1979-08-30 | 1982-09-09 | Otto Dürr Anlagenbau GmbH, 7000 Stuttgart | System for electrophoretic surface coating |
| JPH0768639B2 (en) | 1986-12-10 | 1995-07-26 | トヨタ自動車株式会社 | Electrodeposition coating method |
| JP3877442B2 (en) * | 1998-08-24 | 2007-02-07 | デュポン神東・オートモティブ・システムズ株式会社 | Electrodeposition coating method and continuous electrodeposition apparatus |
| DE19942556C2 (en) | 1999-09-07 | 2003-04-30 | Eisenmann Kg Maschbau | Elektrotauchlackiervorrichtung |
| DE10325656C5 (en) | 2003-06-06 | 2007-12-27 | Eisenmann Anlagenbau Gmbh & Co. Kg | Electrophoretic dip painting system |
| DE10326605A1 (en) * | 2003-06-13 | 2005-01-05 | Daimlerchrysler Ag | Operating method for a cathodic paint dipping plant, especially for coating auto bodies, wherein the current between the cathode car body and distributed anodes is temporally controlled during the process to ensure even coating |
| DE202004021146U1 (en) | 2004-12-22 | 2006-12-21 | Dürr Systems GmbH | Electrodip coating plant comprises current control units that move through the plant together with the workpieces and provide an output voltage for the workpieces |
| DE102006044050A1 (en) | 2006-09-20 | 2008-04-03 | Eisenmann Anlagenbau Gmbh & Co. Kg | Process for the electrophoretic coating of workpieces and coating equipment |
| DE102007006335A1 (en) | 2007-02-08 | 2007-11-22 | Daimlerchrysler Ag | Motor vehicle`s component e.g. metal structure, corrodibility predicting method, involves providing data that characterizes geometries of component of motor vehicle and reservoir, respectively |
| US8313627B2 (en) * | 2008-01-24 | 2012-11-20 | GM Global Technology Operations LLC | Drag through electro-deposition system |
| DE202013009714U1 (en) | 2012-03-02 | 2014-01-02 | Basf Coatings Gmbh | Workpiece coated with an electrodeposition paint |
| US10947636B2 (en) * | 2017-03-21 | 2021-03-16 | Rockwell Automation Technologies, Inc. | Adjustable AC/DC conversion topology to regulate an isolated DC load with low AC ripple |
-
2021
- 2021-05-03 DE DE102021111415.2A patent/DE102021111415A1/en not_active Withdrawn
-
2022
- 2022-04-29 CN CN202221043753.7U patent/CN219315120U/en active Active
- 2022-04-29 EP EP22722408.6A patent/EP4334512A1/en active Pending
- 2022-04-29 US US18/557,388 patent/US20240141539A1/en active Pending
- 2022-04-29 WO PCT/DE2022/100318 patent/WO2022233362A1/en active Application Filing
- 2022-04-29 DE DE112022002358.9T patent/DE112022002358A5/en active Pending
- 2022-04-29 CN CN202210473299.7A patent/CN115287733A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US20240141539A1 (en) | 2024-05-02 |
| WO2022233362A1 (en) | 2022-11-10 |
| EP4334512A1 (en) | 2024-03-13 |
| DE112022002358A5 (en) | 2024-04-04 |
| DE102021111415A1 (en) | 2022-11-03 |
| CN115287733A (en) | 2022-11-04 |
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