JPH0332525Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a water washing device used in the pretreatment process of electrodeposition coating. More specifically, the present invention relates to a water washing device used in a pre-treatment step when electrodeposition coating is applied to an object having a hemming portion and a bag-shaped panel joint portion filled with a structural adhesive in the hemming portion.

[Prior Art] Parts of an object to be coated, such as an automobile body, include the above-mentioned panel joints, such as side doors, back doors, luggage compartment doors, hoods, and fenders. The panel joint portion of the side door will be explained with reference to FIG. Reference numeral 20 denotes an outer panel, on the peripheral edge of which a folded part 21 is formed, and the folded part 21
The peripheral edge of the inner panel 22 and, if necessary, the reinforcement is sandwiched between the inner panel 22 and the hemming portion 23. The hemming part 23 is filled with a structural adhesive 24 (hereinafter referred to as hemming adhesive), and the hemming adhesive hardens when the object to be coated passes through a coating drying oven, and the outer panel 20 and inner panel 22 are bonded together. are completely joined.

On the other hand, in electro-deposition painting of objects such as automobile bodies, in order to remove oils etc. adhering to the body before electro-deposition painting, degreasing is done using an alkaline liquid containing sodium phosphate etc. A pretreatment process is provided, such as degreasing treatment in which the body is immersed in a liquid.

[Problems to be solved by the invention] When electrodeposition coating is applied to an automobile body whose hemming part is filled with hemming adhesive as described above after a pretreatment process such as degreasing treatment, cationic electrodeposition coating is particularly effective. 4, the surface of the electrodeposited film formed near the boundary 25 between the outer panel 20 and the inner panel 22 at the hemming portion 23 shown in FIG. Areas where paint aggregates (hereinafter referred to as spots)
was found to occur in large numbers. In FIG. 4, 26 is an electrodeposition coating film, and 27 is a dot. Thing 2
A gas hole 28 is recognized in the central part of 7.

According to the results of analysis using an X-ray microanalyzer, it was found that sodium atoms were present at a high concentration around the gas holes 28.

Based on this fact, the cause of the occurrence of issue 27 is inferred as follows.

(1) In the pre-treatment process for electrodeposition coating, washing processes such as shower washing and dip washing are provided after the degreasing process, so it is assumed that the degreasing liquid adhering to the body after the degreasing process will be washed away. However, unexpectedly, the alkaline components remained inside the bag structure of the hemming part, and
Normally, sodium ions seep out near the boundary 25 shown in FIG. 3, and when electricity is applied during electrocoating, electric charge is concentrated in that area, causing abnormal adhesion of the paint and causing spots. Particularly in the case of cationic electrodeposition coating, since the alkali concentration in the degreasing solution is high, the amount of alkali remaining in the hemming area is large, and the generation of spots becomes noticeable.

(2) The alkaline component reacts with the paint during electrocoating and generates gas, resulting in gas holes being formed in the spots.

When the above-mentioned spots having gas holes occur in the electrodeposited coating film, the rust prevention properties of the areas are reduced, and the quality of the coating finish is also degraded.

In view of the above-mentioned points, an object of the present invention is to provide a means for preventing the above-mentioned lumps from occurring in the hemming portion.

[Means for Solving the Problems] The present invention has a hemming part, and when applying electrodeposition coating to an object having a bag-structured panel joint part filled with a structural adhesive, the hemming part is filled with a structural adhesive. In addition to the equipment that sprays water onto the object to be coated after the degreasing process and the equipment that sprays water onto the object to be coated after the chemical conversion treatment process, there is also a device that sprays water onto the object to be coated after the degreasing process, as well as between the draining and drying process and the electrodeposition coating process downstream of these. spraying water inside the bag structure of the object to be coated toward the hemming part;
The present invention relates to a water washing device used in a pretreatment process for electrodeposition coating, which is equipped with a device for washing away components that cause defects in electrodeposition coatings present inside the hemming portion from small holes provided near the hemming portion.

[Function] In the pre-treatment process of electrodeposition coating, especially in the process immediately before entering the electrodeposition tank, a device is installed to spray water inside the bag structure of the panel joint area having the hemming area, and the hemming area is actively sprayed. By cleaning the inside, residual alkali can be reduced as much as possible.

[Example] Next, the present invention will be explained based on the drawings.

FIG. 1 is a schematic explanatory diagram showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view taken along the line X--X of FIG. 1.

In the drawings, 1 is an automobile body, and 2 is a side door thereof. Hemming part 23 of side door 2
is filled with hemming adhesive. body 1
are guided and conveyed by a conveyor while being held by the hanger 3, and are subjected to various treatments in the pre-treatment process.

10 is a water washing device related to the present invention. The water washing device 10 includes a pipe 11 extending in a substantially horizontal direction, a nozzle 12 provided at the tip thereof, a support member 13 for the pipe 11, and a drive device 14 that moves the support member 13 in the front and rear direction. The water washing device 10 is designed to move back and forth.

When the body 1 comes to the designated place, the water washing device 1
0 is moved forward, the nozzle 12 is positioned directly above the window glass insertion/removal opening 30 of the side door 2, and water is sprayed from the nozzle 12 into the door interior 31. Hemming part 23 with sprayed water
The interior of the door is cleaned, and the cleaning water is discharged through a small hole (not shown) at the bottom of the door.

In this way, the degreasing liquid remaining inside the door is washed away, the amount of alkali remaining in the hemming area is reduced, the occurrence of spots caused by the oozing of the residual alkali is suppressed, and the electrodeposited coating is formed without any coating defects. It will be done.

After washing, the washing device 10 is moved back so as not to interfere with the conveyance of the object to be coated.

In the water washing device of the present invention, the water spray nozzle 12 can be moved above the window glass insertion/removal opening 30 of the door during washing, and can be moved in cases other than during washing without interfering with the conveyance of the body 1. It is also possible to use devices other than the water washing device 10 as long as they are configured to allow water to drain.

Next, the installation position of the water washing device according to the present invention will be explained.

The pretreatment process for electrodeposition coating generally consists of the following steps.

Preliminary degreasing (shower) → Main degreasing (deep) →
1st flush (shower) → 2nd flush (shower) →
3rd washing (Dip) → Surface conditioning (Dip) →
Chemical treatment (deep) → 4th washing (shower) →
5th flush (deep) → 6th flush (shower) →
Pure water washing (shower) → Draining and drying → (electrodeposition coating) The washing device related to the present invention must be installed after the body is drained and dried before it is placed in the electrocoat bath. This is because some components that are thought to form lumps come out due to the heating during draining and drying, and it is necessary to remove these with a shower.

Although the present invention has been described above with respect to cleaning side doors, it goes without saying that the present invention can also be applied to other luggage compartment doors, hoods, etc.

[Effects of the invention] Since the interior of the panel joint part of the bag structure with the hemming part is actively washed with water in a specific process after the degreasing process, it is possible to avoid problems caused by alkaline seepage of the residual degreasing liquid. The occurrence of bumps is suppressed, and an electrodeposited coating film with no coating defects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing one embodiment of the device of the present invention, Fig. 2 is an enlarged sectional view taken along the line X-X of Fig. 1, and Fig. 3 is an explanatory diagram showing the structure of the hemming part of the door. FIG. 4 is a schematic explanatory diagram showing the state of the electrodeposited coating film in which spots were generated. Main symbols in the drawings: 1: Automobile body, 2: Side door, 10: Washing device, 23: Hemming part, 2
4: Structural adhesive.

Claims (1)

[Scope of utility model registration request] When electrocoating a workpiece that has a hemming part and a bag-like panel joint part filled with a structural adhesive in the hemming part, water is sprayed on the workpiece after the degreasing process. In addition to the equipment that sprays water onto the object to be coated after the chemical conversion treatment process, there is a A water washing device used in the pre-treatment process of electrodeposition coating, which is equipped with a device that sprays water toward the hemming part and washes away components that cause defects in the electrodeposition coating film present inside the hemming part through small holes provided near the hemming part. .