JP3039185B2 - Cleaning equipment in electrodeposition coating process - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus in an electrodeposition coating process for cleaning an object after electrodeposition is performed on the object in an electrodeposition tank.

[0002]

2. Description of the Related Art A coating process of an automobile body usually includes an undercoating process by electrodeposition coating and a middle coating and topcoating process mainly by electrostatic coating, respectively. The object to be coated is cleaned by a cleaning device in order to remove an excessive electrodeposition liquid attached to the object to be coated. This is, for example, the first edition of Automotive Engineering
Vol. 9, "Method of Manufacturing Automobile", April 20, 1980; page 202 to page 208, published by Sankaido Co., Ltd.

[0003]

In a cleaning apparatus, a cleaning liquid is sprayed onto a substrate by spraying, and the sprayed cleaning liquid is collected in a tank and used again for cleaning. Therefore, unnecessary electrodeposition liquid removed from the object to be coated enters the cleaning liquid collected in the tank, and bubbles are generated on the surface of the cleaning liquid falling into the tank. As described above, when the foam is generated, the pigment or the resin material contained in the electrodeposition liquid adheres to the foam, and these are aggregated.

[0004] When the pigment or the resin material is agglomerated, the agglomerated resin material or the like adheres to the surface of the object to be coated when sprayed again together with the cleaning liquid, which adversely affects the coating quality. Was.

The present invention has been made in view of the above-mentioned problems of the prior art, and prevents the generation of agglomerates in a tank for collecting a cleaning liquid sprayed on an object to be coated after electrodeposition coating, thereby improving coating quality. The purpose is to improve.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a cleaning method in which a coating solution is formed in an electrodeposition tank and a cleaning liquid is sprayed on an object carried out of the electrodeposition tank. in the cleaning device in the electrodeposition coating process having a nozzle, wherein the cleaning nozzle and the recovery tank for recovering the washing liquid which is sprayed in a coating object, a defoaming spray for spraying water onto the liquid surface of the collection tank, the Collection tank
Water sprayed from the foam erasing spray provided on the upper surface
A cleaning device in an electrodeposition coating step, comprising: a mesh-shaped filter for diffusing .

[0007]

[Function] The object to be electrodeposited in the electrodeposition tank is
While being conveyed, the substrate is washed with the cleaning liquid from the cleaning nozzle, and unnecessary electrodeposition liquid is removed from the surface of the object to be coated. The cleaning liquid sprayed from the cleaning nozzle onto the object is recovered in the recovery tank and supplied again to the cleaning nozzle. Water is sprayed from the bubble elimination spray toward the liquid level in the recovery tank, and the sprayed water is diffused by the mesh filter and formed on the liquid level in the recovery tank. Bubbles are removed. Bubbles generated on the liquid surface in the collection tank tend to agglomerate the resin and dust in the electrodeposition paint collected in the collection tank, but elimination of the bubbles prevents aggregation. Even when the liquid in the recovery tank is sprayed on the object as a cleaning liquid, the coating quality of the object is not reduced.
In addition, foreign substances such as dust are removed by a mesh filter.
Left.

[0008]

1 and 2 show an embodiment of the cleaning apparatus of the present invention. FIG. 1 is a view showing the first half of the entire cleaning apparatus including an electrodeposition step. FIG. It is a figure showing a latter half part. As shown in the figure, an electrodeposition coating process and a cleaning device are arranged along a conveyor 10 that conveys an automobile body, which is an object to be coated, in a suspended state. An electrodeposition tank 11 for performing electrodeposition coating as undercoating on an automobile body is disposed upstream of the electrodeposition tank, and the electrodeposition tank 11 forms an electrodeposition step. A sub-tank 12 is arranged on the unloading side of the electrodeposition tank 11, and the electrodeposition liquid L discharged by the vehicle unloaded from the electrodeposition tank 11 is stored in the sub-tank 12. In order to return the electrodeposition liquid L in the sub tank 12 to the electrodeposition tank 11, a circulation path 13 is connected between the sub tank 12 and the electrodeposition tank 11, and a pump P and a filter F are connected to the circulation path 13. Is provided.

Downstream of the sub tank 12, first to third
Washing steps 21a to 21c are arranged, and recovery tanks 22a to 22c for collecting the washing liquid sprayed on the vehicle body are provided below the respective washing steps 21a to 21c.
Is arranged. Cleaning nozzles 23a to 23 that spray the cleaning liquid in the recovery tanks 21a to 21c against the vehicle body.
The circulation paths 24a to 24c having the recovery tanks 21a to 21c
21c, and the respective circulation paths 24a to 24c.
4c is provided with a pump P and a filter F.

Downstream of the third rinsing step 21c, a dip rinsing tank 31 is disposed as a fourth rinsing step, and a sub-tank 32 for storing a cleaning liquid overflowing from the dip rinsing tank 31 is disposed on the carry-out side. ing.
A circulation path 34 having a cleaning nozzle 33 for spraying a cleaning liquid onto the vehicle body is connected to the dip washing tank 31. The circulation path 34 is provided with a pump P and a filter F. Further, the dip washing tank 31 has a washing nozzle 35 for spraying a washing liquid on the vehicle body before being carried into the tank.
Is connected.

A final cleaning step 41 is provided downstream of the sub-tank 32. The cleaning liquid in the recovery tank 42 for collecting the cleaning liquid sprayed on the vehicle body in this cleaning step is supplied to a circulation path having a cleaning nozzle 43. 44 to the vehicle body. Further, a cleaning liquid supply path 46 having a cleaning nozzle 45 is provided downstream of the cleaning nozzle 43, and the industrial water supplied into the tank 47 is blown onto the vehicle body by the supply path 46. The vehicle body, which is the object to be coated after the water washing process, is carried into the oven, that is, the drying furnace 51 by the conveyor 10.

FIG. 3A is an enlarged view showing an example of the cleaning apparatus shown in FIGS. 1 and 2. In the illustrated cleaning step 61, a cleaning nozzle 62 applies a cleaning object 62 to an object to be coated. The cleaning liquid is sprayed, and a recovery tank 63 for collecting the sprayed cleaning liquid is disposed below the cleaning step. A pipe 64 is provided for guiding the cleaning liquid sprayed from the cleaning nozzle 62 to the object to be applied to the collection tank 63.

As shown in FIGS. 3A and 3B, a bubble elimination spray 65 is provided above the recovery tank 63, and sprayed water is collected from the bubble elimination spray 65. It is sprayed on the upper surface of the tank 63. As a result, bubbles generated on the liquid surface in the collection tank 63 are eliminated. Therefore, even if bubbles are generated on the liquid surface in the recovery tank 63 by the cleaning liquid guided to the upper surface of the recovery tank 63 via the pipe 64 from the cleaning step, the bubbles are removed, and the pigment caused by the presence of the bubbles is removed. And aggregation of the resin material is avoided. Although only one bubble elimination spray 65 is shown in the drawing, a large number of bubble elimination sprays 65 are placed above the recovery tank 63 so that water is sprayed on the entire liquid surface in the recovery tank 63. It may be provided.

On the upper surface of the recovery tank 63, a wire mesh filter 66 having a mesh, that is, a mesh opening of 50 μm, is provided. To be spread. Therefore, generation of bubbles can be prevented on the entire liquid surface, and no bubbles remain on a part of the liquid surface. Since the cleaning liquid contained in the collection tank 63 passes through the wire mesh filter 66, foreign substances such as dust larger than the mesh (50 μm) of the wire mesh filter 66 are removed at this time. Therefore, it is possible to prevent large dust that remains until after the overcoating step from being applied to the object to be coated when the cleaning liquid is sprayed, and it is possible to reduce the number of defective products. As shown in FIG. 3 (c), in the coating of the automobile body according to this embodiment, when foreign matter such as dust having a size of 70 μm or more adheres in the electrodeposition coating process, the coating surface after the top coating process is performed. In such a case, defects such as irregularities appear, resulting in poor quality (NG). For this reason, the mesh of the wire mesh filter 66 is set to 50 μm.
m or less. Further, a guide flow path 67 is provided from the upper end of the outer periphery of the recovery tank 63 so that the cleaning liquid overflows.
Is formed, and a drain pipe 68 is formed from the guide flow path 67.
Is discharged to the outside. As shown in FIG. 3, a pipe 69 having a pump P is provided, and the cleaning liquid in the cleaning tank 63 is supplied from the pipe 69 to the cleaning nozzle 62.

FIG. 4 shows the number of defective points such as dust and lumps adhering to the object to be coated measured when the bubble elimination spray 65 was not provided (A) as in the illustrated embodiment and when the bubble elimination spray 65 was provided (B). It is a figure showing a result. 4A and 4B,
The horizontal axis indicates time, and the vertical axis indicates the number of defects. From 9 o'clock to 12
Until the time and when the device was operated from 14:00 to 18:00, the number of defectives increased with the lapse of time in the past, but in the present invention, the number of defectives did not increase with the lapse of time. In comparison with the maximum number of defects, the number of defects was reduced by 94%. The cleaning device shown in FIG.
The present invention can be applied to any of the cleaning steps shown in FIG.

[0016]

As described above, according to the present invention, the cleaning liquid sprayed on the object after the electrodeposition coating film is formed is guided to the collection tank, and the liquid level in the collection tank is adjusted. To spray water from the bubble erasing spray , and
Mesh filter provided on top of recovery tank
As a result, the sprayed water is diffused, so that bubbles are prevented from being generated on the entire liquid level in the collection tank, aggregates are prevented from being generated in the bubbles, and the cleaning liquid in the collection tank is coated with the cleaning liquid. No dust or lumps adhere to the object to be coated even when sprayed on, so that high quality coating is possible.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a cleaning apparatus in an electrodeposition coating process according to one embodiment of the present invention;

FIG. 2 is a schematic sectional view showing a cleaning apparatus in an electrodeposition coating process according to one embodiment of the present invention,

3A is a schematic sectional view showing a main part of the present invention, and FIG.
(B) is a plan view showing the collection tank, and FIG. 3 (C)
Is a diagram showing the relationship between the size of dust attached to the electrodeposited body and the size of dust after overcoating,

FIG. 4 is a graph showing experimental data comparing a case where a bubble elimination spray was used and a case where a bubble elimination spray was not used.

[Explanation of symbols]

11: electrodeposition tank, 22a to 22c: recovery tank, 23a to
23c: Cleaning nozzle, 62: Cleaning nozzle, 63: Recovery tank, 65: Foam spray.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-301895 (JP, A) JP-A-3-111594 (JP, A) JP-A-64-56897 (JP, A) 50700 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25D 13/00 307 C23G 3/00

Claims (1)

(57) [Claims] 1. A cleaning apparatus in an electrodeposition coating step, comprising: a cleaning nozzle for spraying a cleaning liquid onto an object carried out of the electrodeposition tank after an electrodeposition coating film is formed in the electrodeposition tank. A collection tank for collecting the cleaning liquid sprayed on the object to be coated, a bubble elimination spray for spraying water on a liquid surface in the collection tank,
Water sprayed from the foam erasing spray provided on the upper surface
A cleaning device in an electrodeposition coating step, comprising: a mesh-shaped filter for diffusing .