KR20190077936A - Electrodeposition coating system increasing efficiency - Google Patents

Abstract

The present invention provides an electrodeposition coating system increasing efficiency, uniform coating is treated on a surface of an object to be coated, and individual voltage of a plurality of positive plates provided in an electrodeposition tank can be controlled. Therefore, when an object to be coated with a thin thickness or an object to be coated with different thicknesses in each portion is electrodeposition coated, a predetermined film thickness is formed to secure wear resistance of a film and significantly reduce a ripple rate.

Description

ELECTRODEPOSITION COATING SYSTEM INCREASING EFFICIENCY "

The present invention relates to an electrodeposition tank in which a water-borne coating material for forming a coating film is formed on a surface of a substrate, a plurality of positive electrode plates provided in the electrodeposition tank along a longitudinal direction thereof, And an IGBT (Insulated Gate Bipolar Transistor) rectifier for supplying a positive (+) power to the positive plate while supplying a negative (-) power to the energizing rail. To an electrodeposited coating system.

Generally, in the automobile manufacturing process, the body coating line forms a coating film on the surface of a body formed by welding each press-molded part, thereby preventing corrosion of the body, and providing a beautiful appearance together with soundproofing and anticorrosion.

The above-mentioned body coating line is used for an electrodeposition (bottoming) process for forming an electrodeposited film to provide corrosion prevention and rust prevention of a vehicle body, a middle process for imparting dipping resistance, smoothness and weatherability of a paint forming a coating film, A top process for giving a gloss feeling, a clear process, and the like.

In the electrodeposition process in the above-described body coating line, an electrodeposition phenomenon and an electrolytic action are generated in the electrodeposition solution contained in the electrodeposition bath to form an electrodeposited film on the surface of the body.

1 is a schematic view for explaining a general electrodeposition coating system.

As shown in FIG. 1, conventionally, when the electrodeposition coating is repeated, dipping and spray washing are repeated to transfer the body B, which has passed the pre-treatment step, along the rails 5 provided on the upper side of the electrodeposition tank 3 And is then housed in the electrodeposition tank 3 containing the electrodeposited liquid in a state of being mounted on the hanger 1. [

At least one or more diaphragms 6 for applying a positive (+) power to the electrodeposited liquid are disposed on the inner wall of the electrodeposition tank 3, and the hanger 1 is provided with a body B And a hanger bracket 4 connected to the rail 5 through a hanger supporting bar 9 are respectively mounted and a three-phase alternating current high voltage is applied to the hanger bracket 4 A rectifier (not shown) for supplying a positive (+) power to the diaphragm and a minus (-) power supply for the electrification rail is separately provided outside the electrodeposition bath. The hanger bracket 4 is provided with an insulating unit 8 for shielding the power applied to the energizing rail 7 from being energized to the rail 5 while supporting the vertical load of the hanger 1. [ Therefore, the vehicle body B having been subjected to the pretreatment process is mounted on the hanger 1 transferred along the rails 5 provided on the upper side of the electrodeposition tank 3, (+) Power is supplied to the electrodepositing liquid through one or more diaphragms 6 constituted by one or more pluralities and a minus (-) power source is supplied to the vehicle body B through the energizing rail 7, Electrophoresis and electrolytic action are generated to deposit an electrodeposited component and the deposited electrodeposited component moves to the surface of the body to form an electrodeposited film.

Meanwhile, in the conventional electrodeposition coating system, an AC voltage is turned on at a certain point within a cycle so that a negative power can be supplied to the energizing rail, and then a DC voltage is generated, and then a DC voltage is controlled through a conduction angle control A rectifier of SCR (Silicon Controlled Rectifier) method was used.

However, since the electrodeposition coating system equipped with the SCR rectifier has a low frequency and efficiency, the electric power consumption is remarkably high, the current density is low due to low frequency output, and the thickness of the coated surface of the product is not uniform. And a ripple ratio of 20% or more was generated.

In addition, when the ambient temperature is 30 ° C or higher during the summer season, there is a problem that the overheat warning sound frequently occurs, and the preliminary rectifier is not provided, so that the entire painting process is interrupted until the problem is solved.

Moreover, the SCR rectifier is a simple sequence control method, and thus has a problem in that a lot of cost is required for the parallel configuration and the PLC control.

It is an object of the present invention to provide an electrodeposition coating system which is capable of reducing electrodeposition at a high speed and having a low power consumption and capable of remarkably reducing a ripple rate.

According to another aspect of the present invention, there is provided an electrodeposition coating apparatus comprising an electrodeposition vessel filled with a water-borne coating material for forming a coating on a surface of a substrate, a plurality of positive electrode plates provided in the electrodeposition vessel along a longitudinal direction, An insulated gate bipolar transistor (IGBT) rectifier for supplying a plus (+) power to the positive plate and a minus (-) power supply to the energizing rail while supplying a positive (+) power to the positive plate .

In addition, in the present invention, the IGBT rectifier is provided in a ratio of 1: 1 with the positive electrode plate, and is connected in series with each positive electrode plate to adjust the voltage of each positive electrode plate. Thus, And a coating film thickness is formed at the time of coating to reduce sesame spin defectiveness.

Further, the present invention provides a controller having a display screen which is electrically connected to each of the IGBT rectifiers to display a voltage value and a current value set in each of the positive electrode plates, The control unit compares the target current value set in advance with the current value fed back from the detecting unit, and when the positive electrode plate that does not meet the condition is detected, the error information of the rectifier is transmitted through the display screen so that quick action can be taken .

The electrodeposition coating system according to the present invention as described above can output a high-speed pulse to uniformly coat the surface of the substrate, increase abrasion resistance of the film, and significantly reduce the ripple rate There are advantages.

In addition, the IGBT rectifier of the present invention is provided in a ratio of 1: 1 with the positive electrode plate, but they can be connected in series to each other so that the voltage of each positive electrode can be adjusted through the controller. Therefore, the electrodeposition coating of a thin- It is possible to reduce the sesame spin defect.

In addition, the control unit compares the target current value set in advance with the current value fed back from the detection unit, and when a bipolar plate that does not meet the condition is detected, error information of the rectifier is transmitted through the display screen, Since the process line can be continuously operated without interruption, it is advantageous in workability, productivity and efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view for explaining a conventional electrodeposition coating system; Fig.
FIG. 3 is a photograph showing a ses-spin picture taken on the surface of a substrate through an electrodeposition coating system according to the related art.
4 is a schematic view showing an electrodeposition bath according to an embodiment of the present invention.
5 is a schematic illustration of an IGBT rectifier according to an embodiment of the present invention.
FIGS. 6 to 7 are schematic illustrations for explaining a first rectifying section according to an embodiment of the present invention; FIG.
8 to 9 are schematic illustrations for explaining a frequency modulation unit according to an embodiment of the present invention;
10 is a photograph of a display screen of a controller according to an embodiment of the present invention.

Hereinafter, an electrodeposition coating system having improved efficiency according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention discloses an electrodeposition coating system that can increase the abrasion resistance of a coating film by uniformly painting the surface of the substrate, and can significantly reduce the ripple rate and power consumption.

According to another aspect of the present invention, there is provided an electrodeposition coating apparatus comprising an electrodeposition vessel filled with a water-borne coating material for forming a coating on a surface of a substrate, a plurality of positive electrode plates provided in the electrodeposition vessel along a longitudinal direction, And an IGBT (Insulated Gate Bipolar Transistor) rectifier for supplying a positive (+) power to the cathode plate while supplying a negative (-) power to the electrifying rail, in the electrodeposited coating system including the electrifying rail .

The substrate is a metal product in which an electrodeposited film is formed on the surface. Examples of the substrate include front and rear frames constituting the skeleton of a vehicle, and automobile materials such as carriers and cross members of automotive batteries.

Generally, when the productivity, workability, and economy are taken into consideration, the time of staying in the electrodeposition tank is about 4 minutes, and the initial voltage must be changed in order to complete the coating process required by the consumer within a given time. This is because the area and the thickness are different for each product. For example, in the case of a large-sized large-sized vehicle such as a forward or a rear frame constituting a skeleton of a vehicle, the initial voltage is set high during electrodeposition coating, The voltage should be lowered gradually, and it is advisable to set the initial voltage low, and gradually increase the voltage according to the progress of the small cargo such as the carrier or the cross member of the vehicle battery. For example, when the voltage of the logistics is set to the object of the small logistics, the paint is applied beyond the thickness required by the consumer, so that the quality of the product is deteriorated (film breakage and sesame spin defect) A problem occurs.

The electrodeposition tank is filled with a predetermined amount of water-borne water-borne paint to form a coating film on the surface of the substrate, and an energizing rail mounted on the hanger for energizing a minus (-) power source Respectively.

In addition, a plurality of positive electrode plates are provided on the inner walls on both sides of the electrodeposition tank.

In the positive electrode plate, positive (+) power is supplied to the electrodeposited liquid contained in the electrodeposition tank. (+) Power source which is energized to the electrodepositing liquid through the positive electrode plate and a negative (-) power source which is energized to the vehicle body which is immersed in the electrodepositing liquid through the energizing rail cause electrophoresis and electrolysis in the electrodeposition liquid, .

The electrodeposition component precipitated in the electrodeposition liquid is transferred to the surface of the body where a negative (-) power source is energized to form an electrodeposited film.

For example, as shown in FIG. 4, six positive electrode plates 20 are disposed on the left and right inner walls of the electrodeposition tank 10, respectively. The positive electrode plates 20 are disposed on the left and right inner walls of the electrodeposition tank 10, And can be arranged at regular intervals along the longitudinal direction. The number of the positive electrode plates is not limited to the scope of the present invention.

The IGBT rectifier is a rectifier device by PWM control in a high frequency switching system using an IGBT element, converts a commercial voltage to a DC voltage, supplies a minus (-) power to the energizing rail, Supply.

Conventionally, in a conventional electrodeposition coating system, a rectifier of SCR (Silicon Controlled Rectifier) method is used as a rectifier. However, since the frequency and efficiency are low, the power consumption is remarkably large and the current density is low at a low frequency output, So that a severe sesame spin defect often occurs on the surface of the coating film of the substrate, resulting in a ripple ratio of 20% or more.

In the present invention, an IGBT rectifier is used as a rectifier. The IGBT rectifier generates PWM (Pulse Width Modulation, square wave) method which generates an output wave more than 25,000 times per second in comparison with the SCR rectifier and greatly reduces high current and low current deviation (88 to 95% or more), low ripple (output room load condition: less than 2%), high current density due to high density energy application And the uniformity of the paint can be maintained by reducing the deviation.

5 is a schematic view illustrating an IGBT rectifier according to an embodiment of the present invention.

In the present invention, the IGBT rectifier 100 mainly includes a first rectifier 110, a frequency modulator 120, a second rectifier 130, a final smoother 140, and a control circuit 150 .

6, the primary rectifier 110 includes a diode 111 for converting a commercial power source (alternating current) into a direct current (pulsating current), and a diode 111 for converting a commercial power source And a smoothing circuit portion 112 for smoothing the included pulsation component.

The frequency modulator 120 includes an inverter unit 121 and a transformer unit 122.

The inverter unit 121 is a known device for converting the DC power converted through the primary rectification unit 410 into AC power, and turns the IGBT element on and off to convert it into an AC power of 60 to 25,000 Hz. Specifically, referring to FIG. 8, the inverter unit obtains an alternating current power by alternately switching the direct current (DC) power converted through the first rectifying unit 110 to the IGBT elements of the inverter unit. That is, the inverter unit 121 turns on the first switch S1 and the fourth switch S4 of the IGBT element so that the current flows in the direction A. The second switch S2 and the third switch S3 are turned on, And the current flows in the B direction. If the above operation is repeatedly performed, the flow direction of the DC current from the first rectifying part is changed so that the alternating current output voltage of the primary side of the transforming part is obtained. 1 to the fourth switches S1, S2, S3, S4 by changing the operating time of the first to fourth switches S1, S2, S3, S4. FIG. 9 is an exemplary diagram showing a current waveform when a DC power source is converted to an AC power source. FIG.

The transformer 122 converts the value of the alternating voltage or current from the inverter unit 121 by using an electromagnetic induction action, and obtains a desired voltage and current by adjusting the primary to secondary voltage ratio.

The secondary rectifying unit 130 rectifies the AC power from the inverter unit and the transforming unit to a direct current power by using a rectifying diode, and the diode of the secondary rectifying unit must be higher in speed than the diode used in the primary rectifying unit , Ultra Fast Recovery, or Schottky Barrier diodes.

The final smoothing unit 140 smoothes the waveform by concurrently providing a reactor and a condenser at the output end of the secondary rectifying unit.

The control circuit unit 150 includes a detection unit 151 and a control unit 152. The detection unit 151 measures the voltage and current of the output terminal of the secondary rectification unit and feeds back the measured voltage and current to the control unit. The control unit 152 compares the voltage and current values fed back from the detection unit with preset voltage and current values And controls the voltage and current of the rectifier.

Table 1 below shows the power consumption of the electrodeposition coating system equipped with the SCR rectifier according to the embodiment of the present invention, Table 2 shows the monthly power consumption of the electrodeposition coating system provided with the IGBT rectifier, The annual electricity cost savings derived are listed.

Table 1 shows the electric power consumption of the electrodeposition coating system equipped with the SCR rectifier. year month Operation time (h) Power (KW) Power per hour (KW / h) April 2015 283 11,121 39 May 2015 264 10,021 38 June 2015 303 11,286 37 July 2015 280 10,785 39 August 2015 188 7,101 38 sub Total 1,318 50,314 38

Table 2 shows the electric power consumption of electrodeposition coating system equipped with IGBT rectifier. year month Operation time (h) Power (KW) Power per hour (KW / h) April 2016 271 5,474 20 May 2016 283 5,776 20 June 2016 257 5,302 21 July 2016 269 5,220 19 August 2016 246 4,664 19 sub Total 1,326 26,436 20

Table 3 shows the annual electricity cost savings derived from Tables 1 and 2. Annual electricity cost savings (KRW) Power per hour
(KW / h) Working hours
(h) Monthly working day
(Work) year unit price
(won) Sum
(won) 18 10 25 12 126 6,893,902

As can be seen from Tables 1 and 2, the electrodeposition coating system having the IGBT rectifier according to the present invention has a smaller amount of electric power consumption per hour than the electrodeposition coating system having the SCR rectifier, A remarkable reduction effect can be obtained.

Next, in the present invention, the IGBT rectifier 100 is provided at a ratio of 1: 1 with the positive electrode plate 20, and is connected in series with each positive electrode plate.

In the electrodeposition coating system in which the conventional SCR rectifier is provided, a plurality of positive electrode plates are collectively controlled by one SCR rectifier. Therefore, when a predetermined voltage value is input to the SCR rectifier, the same voltage is supplied to all the connected positive plates according to the input conditions. However, when the same voltage is applied to all the positive electrode plates as described above, when the electrodeposited coating material having a thin thickness or a different thickness is applied to the positive electrode plate, the thickness of the coating film is not constant depending on the thickness or the area, .

Accordingly, the present invention provides an IGBT rectifier in a ratio of 1: 1 with a positive electrode plate provided in the electrodeposition tank, and is connected in series so that individual voltage adjustment can be performed for each positive electrode plate, It is possible to obtain an effect of reducing the sesame spin defect by forming a constant film thickness during electrodeposition coating of the substrate. For example, in the electrodeposition of a metal substrate having a thin thickness, the voltage of the positive electrode plate on the front side of the electrodeposition tank may be set to be relatively low as compared with the voltage of the positive electrode plate on the rear side, so that a good quality coating film can be formed.

Further, the present invention provides a controller having a display screen which is electrically connected to each of the IGBT rectifiers to display a voltage value and a current value set in each of the positive electrode plates, .

FIG. 10 is a photograph of a display screen of a controller according to an embodiment of the present invention, wherein a total of twelve positive plates are provided in an electrodeposition tank, the voltage of the first positive plate is 271 V, the voltage of the second positive plate is 273 V , And the voltage of the third positive electrode plate is 274 V. It can be confirmed that the voltage values of the respective positive electrode plates are set to be different from each other, and emergency buttons for collectively stopping all the rectifiers in the event of manual control and emergency situations .

Since the conventional SCR rectifier is connected to all the positive plates in the electrodeposition tank, the switching speed is slow, the parallel control and program control are difficult, and it takes a long time to recover when a single facility fails. There is a problem that the productivity and efficiency are remarkably deteriorated.

On the other hand, according to the present invention, when the cathode plate and the IGBT rectifier are connected in a 1: 1 ratio, the control unit compares the preset target current value with the current value fed back from the detection unit, So that the operator can quickly correct the error of the rectifier, so that the painting system can be continuously operated without interruption.

In addition, in the event of a failure, the operator can simply transfer the output line from the distribution panel of the rectifier, thereby enabling continuous production without interruption of the coating line. For example, if the OUT line cable is connected to the OUT line of the rectifier 2 when the rectifier 1 fails, the rectifier 1 can be used immediately, so that the workability and productivity can be prevented from being deteriorated through quick response. 11)

The electrodeposition coating system having the IGBT rectifier according to the present invention can uniformly coat the surface of the substrate. In particular, the IGBT rectifier is connected to the positive electrode plate at a ratio of 1: 1, Since it is possible to control the voltage, it is possible to form a constant film thickness during electrodeposition of a thin substrate or a substrate having a different thickness for each site, so that the abrasion resistance of the film can be secured and the ripple rate can be remarkably reduced have.

10: electrodeposition tank
20: positive electrode plate
100: IGBT rectifier

Claims (3)

A plurality of positive electrode plates provided in the electrodeposition tank in a plurality of lengthwise directions and a conductive rail provided on an upper side of the electrodeposition tank; In the electrodeposition coating system,
And an IGBT (Insulated Gate Bipolar Transistor) rectifier for supplying a positive (+) power to the positive electrode while supplying a negative (-) power to the energizing rail.
The IGBT rectifier according to claim 1, wherein the IGBT rectifier is provided in a ratio of 1: 1 with the positive electrode plate, and is connected in series with each positive electrode plate to adjust the individual voltage of the positive electrode plate, Wherein an effective coating film thickness is formed at the time of electrodeposition coating to reduce sesame spin defect.
3. The method according to claim 1 or 2,
And a controller electrically connected to each IGBT rectifier to display a voltage value and a current value set to each of the positive electrode plates and a display screen capable of a touch screen function so as to set a voltage value of each positive electrode plate,
The control unit compares the target current value set in advance with the current value fed back from the detecting unit, and when a bipolar plate that does not meet the condition is detected, the error information of the rectifier is transmitted through the display screen so that quick action can be performed Electrodeposition coating system.

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