JPH0432157B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is used in the technical field of electro-deposition coating for car bodies. The present invention relates to an electrodeposition coating method in mixed production in which coating films of different thicknesses are formed according to the requirements.

(Prior Art) In the conventional continuous electrodeposition coating method for car bodies, the number of cars that can be applied to one painting line including an electrodeposition tank is limited to the same car model. In the case of different car models, the paint was applied to different paint lines. This means that if different types of car bodies are sent to the same painting line, the coating quality required for the objects to be painted will be uniform regardless of whether it is high quality (thick paint film) or low quality (thin paint film). This is because the film is coated too thickly.

Further, as a prior art, Japanese Patent Publication No. 49-2968 describes a method of applying a thin coating by soft-starting the electrode voltage near the entry section when the object to be coated enters the tank.

Further, as a method of controlling the coating film thickness by changing the immersion area of the electrode in the tank, Japanese Patent Application Laid-Open No. 52-127947
Although disclosed in the above publication, none of them is based on the technical idea of controlling the coating film thickness by sending car bodies of different car models to the same painting line.

(Problems to be Solved by the Invention) As described above, in the conventional method, in order to simultaneously paint luxury cars, mass-market cars, luggage cars, etc., which require different painting qualities (paint film thicknesses),
This method not only requires a large number of painting lines, which increases equipment costs, but also requires a large equipment area.

That is, an object of the present invention is to enable different types of vehicle bodies having different required paint film thicknesses to be painted with the required film thickness even if they are sent to the same painting line.

(Means for Solving the Problems) In order to solve these problems, the present invention uses a sensor to detect different types of cars, such as early luxury cars and popular cars, and also detects when the required paint film thickness is thin. The purpose is to reduce the number of electrodes used.

In other words, this method is an electrodeposition method in mixed production in which different types of car bodies with different required coating film thicknesses are continuously fed into an electrodeposition bath equipped with a large number of electrodes and applied with electrodeposition coating. This is a painting method in which the type of car body that is about to enter the tank is determined and detected using a car type detection sensor installed in front of the tank section of the electrocoating tank, and the thickness of the paint film required for the car body that is about to enter the tank is determined. For car models, increase the number of electrodes used in the electrodeposition tank, and for car models with a thin coating film thickness required for the car body to be entered into the tank, reduce the number of electrodes used in the electrodeposition tank. This is a characteristic feature.

(Function) In the electrodeposition coating method in the above mixed production,
In the case of a car model that requires a thicker coating film, the number of electrodes used is increased, which increases the amount of paint electrodeposited on the vehicle body, resulting in a thicker coating film. On the other hand, in the case of a car model that requires a thin coating film thickness, the number of electrodes used is reduced, so the amount of paint electrodeposited on the car body is reduced, resulting in a thin coating film thickness.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

To explain the coating equipment used to carry out the electrodeposition coating method in mixed production of the present invention, Figures 1 to 3
As shown in the figure, 1 is an electrodeposition tank, 2 is an electrodeposition liquid in the electrodeposition tank 1, and the electrodeposition liquid 2 is usually left and right (see Figure 2).
15 to 20 electrodes (anodes) are provided at predetermined intervals. In FIGS. 1 and 3, the number of electrodes is small on one side only, but electrodes 3a, 3b, and 3c can be energized intermittently, and electrodes 3d, 3e, 3f, and 3g are energized normally. It is.

Above the electrodeposition bath 1 is a rail 5 of the conveyance line 4.
is provided, and a mixture of a luxury car body 7, which requires a thick coating film thickness, and a mass-market vehicle body 8, which requires a thin coating film thickness, are suspended from the hanging tool 6 moving on the rail. A vehicle type detection sensor 9 is provided at an appropriate position in front of the vehicle body being transported into the electrodeposition bath 1. A comparison and discrimination device 10 is connected to the detection sensor 9, and the vehicle type is determined by the device 10. The detection sensor 9 uses, for example, a phototube to read a code tag pasted on the car body, or detects the car type through a hole drilled in the car body, and based on this detection, the solenoid switch 11 is activated to detect the type of car. In the case of 7, it is set to ON, and in the case of mass car body 8, it is set to 0FF. The power source is negative on the car body side, electrode 3
The a to 3g sides are connected to the positive terminal.

The electrodes 3a, 3b, 3c are provided on the side closer to the bath entry part as shown in FIG.
are connected to the contact 12 of the electrodes 3a, 3
Along with b and 3c, there are several electrodes 3d in front of them,
3e, 3f, 3g are provided, and these electrodes 3d~
3g is connected to the contact 13 of the solenoid switch 11, and further connected to the positive pole of the power source.
Next, to explain the coating method of the present invention, when the car body conveyance line 4 is in operation and each car body 7, 8, etc. is moving to enter the electrocoating tank 1, the car body 7, 8, etc. In this case, the comparison and discrimination device 10 is activated by the signal from the detection sensor 9, and the solenoid switch 11 is turned on. In this case, the electrodes 3a,
3b, 3c, 3d, 3e, 3f, and 3g are all connected to the positive side of the power source 14, and the luxury car body 7 entering the tank will be coated with a thick coating of high quality. If the next vehicle to enter the tank is the mass vehicle body 8, the detection sensor 9 and comparison/discrimination device 10 and the mass vehicle body 8 are installed in a separate sheet, and the solenoid switch 1 is installed as described above.
The contacts 12 and 13 of No. 1 are not electrically conductive, therefore, the electrodes 3a, 3b, 3c are not connected to the power source 14, and the thin electrodes 3d, 3e, 3f and 3g in the electrodepositing solution 2 are electrodeposited only. Painted in a thick film. .
After the conveyed car bodies 7 and 8 finish painting and rise from the electrodeposition tank 1, they are sent to a washing device (not shown).

An example of the coating conditions in the above embodiment is as follows.

Voltage: 300±20V Energizing time: 3 to 4 minutes Paint concentration: 20±1% Paint film thickness: 25μ on the outer panel of luxury cars, 20μ on the outer panels of mass-market cars.In addition, there are areas where the paint is thick, which often occurs when entering the tank. Conventionally, linear painting, etc., has been controlled by controlling the current to the electrodes when entering the tank or by inserting a shield plate between the electrodes and the vehicle body. Although the above method can also be used in the present invention, the electrode 3
When electricity is cut off to a, 3b, and 3c, only the electrodes 3d, 3e, 3f, and 3g are energized, and the car body and electrode 3 in the transport direction of the car body transport line 4 are energized.
d, 3e, 3f, 3g are the electrodes 3a, 3
Since electrodes 3d, 3e, 3f, and 3g are separated by the amount that they are not used, the current between the electrodes 3d, 3e, 3f, and 3g and the vehicle body is small, preventing linear paint marks caused by excessive current when entering the tank, which previously occurred. can do.

The electrodes 3a to 3g do not necessarily have to be arranged in order in the electrodeposition liquid 2, but can also be arranged alternately as shown in FIG.

Further, in the embodiment, the vehicle body is used as a cathode and the electrode is used as an anode, but the polarity may be reversed.

(Effects of the Invention) According to the present invention, the types of car bodies with different required coating film thicknesses are detected before entering the electrodeposition tank,
If the required paint film thickness is hot, the number of electrodes used is increased, and if the required paint film thickness is thin, the number of electrodes used is reduced. It is possible to easily obtain coating films with different thicknesses depending on the vehicle type by running them on the same coating line even though the thicknesses are different, thereby improving productivity.

[Brief explanation of drawings]

The drawings illustrate embodiments of the method of the present invention;
Figure 2 is a sectional view taken along the - line in Figure 1;
The figure is a front view of main parts of an electrodeposition coating apparatus in another embodiment. 1...Electrodeposition tank, 3a, 3b, 3c...Intermittent electrode, 3d, 3e, 3f, 3g...Common electrode, 7...
... Luxury car body, 8... Mass car body, 9... Detection sensor, 10... Comparison/discrimination device, 11... Solenoid switch.

Claims (1)

[Claims] 1. An electrodeposition coating method in mixed production in which different types of vehicle bodies with different required coating film thicknesses are sequentially supplied and immersed into an electrodeposition bath equipped with a large number of electrodes to apply electrodeposition coating, A vehicle type detection sensor installed in front of the tank entry section of the electrodeposition tank detects the type of car body that is about to enter the tank, and if the type of car body that is about to enter the tank requires a thick coating film, the above In mixed production, the number of electrodes used in the electrodeposition tank is increased, and in the case of a car model whose paint film thickness required for the car body to be entered into the tank is thin, the number of electrodes used in the electrodeposition tank is reduced. Electrodeposition coating method.