JPS5847232B2 - Pretreatment method for painting - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for pre-painting an automobile body, etc., and in particular, detects irregularities, scratches, etc. on the surface of an object to be painted and corrects them before the pre-painting process. The present invention relates to a pretreatment method for painting that can be performed.

When assembling an automobile body, surface irregularities and scratches are corrected when each panel is pressed, and further, after the vehicle body is assembled, the surface irregularities and scratches are corrected again.

However, at the time of these repairs, the car body was covered in oil and dust, making it difficult to detect small irregularities and scratches, and there was a limit to the repairs that could be made.

Any small irregularities or scratches that were overlooked during this correction will be sent to the painting process.

In the painting process, irregularities and scratches are discovered during the inspection process of the coated object after the pretreatment process and the undercoating process using electrodeposition coating.

Therefore, after completing the undercoating, it is necessary to repair the defective parts again with the sheet metal, and the high-quality undercoat film that has been painted will be peeled off. There is a problem that the quality is lower than that of the other parts.

Further, the above-mentioned painting repair requires a considerable number of man-hours, and the work is extremely complicated.

Furthermore, if the repaired area is spread over a wide area, it is necessary to apply electrodeposition coating again, which increases the cost (1).

On the other hand, since the paint film is peeled off during repair, there are also problems such as the need for equipment to deal with the dust generated during the repair process.

This invention was made in view of the above, and by providing a pre-treatment step to clean the surface of the object to be coated and give it gloss before the pre-treatment step during painting, the surface of the object to be coated can be coated at a stage before the formation of the paint film. To provide a pretreatment method for painting, which cleans the surface of a painted object and gives it luster to make it easier to find surface defects, thereby eliminating the need for repair work after the formation of a paint film.

Hereinafter, this invention will be explained based on the drawings.

FIG. 1 is a block diagram of a painting process employing the present invention, taking painting of an automobile body as an example.

When installing doors, trunk lids, hoods, etc., the car body is first subjected to a preliminary treatment step 1, and then in a repair step 2, defects in sheet metal are immediately discovered and corrected.

Next, a pre-treatment process 83 such as degreasing and chemical conversion treatment is carried out, followed by an electrodeposition painting process 4 and an electrodeposition washing process 5. After that, the doors and, if necessary, the trunk lid, hood, etc. (hereinafter referred to as doors, etc.) are removed in a door removal process 6. They are arranged from the car body, and in a sealing process T, the doors, etc. and the car body are individually sealed.

Next, at the same time as the intermediate coating process 8 of the outer panel, the internal top coating process 9 is carried out.
Then, in step 10, the door is attached to the vehicle body again, followed by a sanding step 11, and a final coating step 12.

In the top coating process, the main painting work is performed by a reciprocator (painting process 13), but the painting of local areas that cannot be sufficiently coated with these automatic machines is done by robots instead of the traditional human work, and what is more, the robots perform the local painting by robots. The coating process 14 was placed in the front process of the automatic machine mentioned above.

After the painting is completed, the vehicle body is subjected to an inspection step 15, and the defective vehicle body is returned to the top coating step 12 as shown by the broken line in the figure.

Note that 17 in the figure indicates a drying process, and the portions indicated by two-dot chain lines in the figure can be omitted.

Next, each of the steps outlined above will be individually explained in detail.

Pretreatment process (preliminary cleaning) 1; Repair process 2 The silver and gold surface of the car body is treated with a degreaser consisting of an alkaline component such as sodium phosphate and sodium and a surfactant, spindle oil, a nonionic surfactant, and an organic amine rust preventive. Clean with a mixture of brighteners, etc.

As this liquid mixture, for example, an aqueous solution obtained by diluting the stock solution of Barcot Breclean (trade name, manufactured by Nippon Parkerizing KK), which is commercially available, is used.

For cleaning, flow coating using a nozzle and cloth is used to uniformly apply the liquid.

According to this flow coat, almost no ceratemp time is required after washing the car body.

This cleaning removes dust, oil, etc. from the car body surface, and increases the gloss of the surface to make it suitable for inspection, making it possible to clearly identify scratches, silver and gold defects, etc. on the surface, and immediately proceed to the repair process. The correction can be made in .

This eliminates the need for correction after completion of painting, that is, scraping off the electrodeposition coating, and prevents deterioration in the quality of the coating and obstruction of the flow of the object to be coated.

Here, if a clear type brightener is used, it is difficult to see irregularities on the surface of the vehicle body, and long-term inspections cause significant eye fatigue, so it is desirable to form this into an emulsion.

Furthermore, while it is easy to see the wet surface of the car body during inspection, a dry state is suitable for silver and gold work, so it is desirable to use a liquid that satisfies the image point.

Incidentally, the liquid may be provided with anti-corrosion properties.

Pretreatment step 3: This is a step aimed at degreasing and chemical conversion of the silver/gold surface, similar to the conventional method, which includes preliminary degreasing, degreasing, washing with water (or surface conditioning with oxidative acid solution), washing with water (or washing with hot water), and coating. Chemical conversion treatment - Water washing (or hot water washing) - Water washing (or hot water washing) - Pure water washing is performed, but in preliminary degreasing, degreasing, film chemical treatment and some water washing (or hot water washing) processes, conventional spray In addition to the one-way method, an immersion method is used.

The immersion method (0) is characterized by immersing approximately the lower half of the car body in the treatment liquid, which makes it possible to chemically treat the inside of the car body, especially the inside of the bag-shaped parts, which is difficult to do with a one-way spray method. This improves corrosion resistance.

Furthermore, by immersing only approximately the lower half of the vehicle body, the equipment space can be reduced compared to the case where the entire vehicle body is immersed.

Electrodeposition coating step 4: This is the same as the conventional method, and either an anionic or cationic electrodeposition method can be adopted, but the cationic method is preferable from the viewpoint of corrosion resistance.

Electrodeposition washing step 5: In this washing step, in addition to the conventional spray method, an immersion method in which the entire vehicle body is immersed in a water washing bath is used.

Merely washing the paint (non-electrodeposited paint) adhering to the surface of the car body with water using only the spray method is not perfect and tends to cause unevenness in the electrodeposited film.

For this reason, conventionally, this unevenness was eliminated by air grinding after electrodeposition, but by performing immersion washing in this way, such unevenness is eliminated, so air grinding after electrodeposition can be omitted. .

In addition, in this water washing process, the so-called limit 9'4 is washed with water using the filtrate, and as shown in FIG. The water is supplied to the washing tank 22 and mixed with washing water, and this used water is sequentially overflowed to each washing liquid tank of the upstream spray washing section 23, 24, and in each washing section, the
Washing water containing filtrate is circulated and used for spray washing.

If the electrodeposition washing process 5 is completely closed cycle, contaminants will accumulate in the electrodeposition bath, which will interfere with the electrodeposition bath management. .

Furthermore, it is preferable to perform washing with deionized water at the end of the washing step.

Arranging doors, etc. step 6, sealing step γ, outer panel intermediate coating step 8, and interior top coating step 9: Doors, trunk lids, hoods, and other items that are attached to the vehicle body and cover the openings of the vehicle body are arranged.

The arranging work can be done by humans or by automatic machines.

The removed doors and the vehicle body are subjected to a sealing process 11, a plate intermediate coating process 8, and an internal top coating process 9, respectively.

At this time, the plate sealing process can be performed automatically using a reciprocator industrial robot, etc. as in the past, but in this example, the plate sealing process can be performed automatically by removing the door etc. from the car body. Since the robot's arm and paint piping do not interfere with doors, etc., it is possible to automate the sealing and painting of the inside of the car body as well as the inside of the door etc. by the robot.

Here, the inside of the door refers to areas where the painted surface is exposed after final assembly, such as the inside of the door and the side of the door.

Therefore, robots can automate the painting of the inside of the car body, side sills, door openings, doors, etc., which could only be done by humans in the past, which saves manpower and improves interpersonal measures even in the painting work environment. This will result in a significant reduction in equipment costs, etc.

Moreover, by removing the door and painting the door alone, it is possible to treat the inside of the door bag through the working hole on the inside of the door, which is effective in terms of rust prevention.

Incidentally, since the interior has already been topcoated in this step, the work in the topcoating step 12 in the subsequent step is simplified.

In particular, the top coating process is performed with doors etc. installed, so
This simplifies the work compared to the conventional method of top-coating the inside and outside at the same time, making it extremely easy to arrange a general-purpose or specialized industrial robot in the top-coating booth.

Door etc. installation step 10, sanding step 11: Attach the door etc. to the vehicle body again.

It doesn't matter whether the vinegar industry is done by humans or by automatic machines.

In this case, if the color of the car body and doors, etc. can be completely matched even if they are painted separately in the final coating process described later, the removal of the doors, etc. may be performed after the final coating process. .

In this way, for example, if the hood is attached as a later process, the engine installation work during automobile assembly becomes easier.

Sanding is almost the same as before.

Top coating process 12 [local coating process 14, remainder coating process 13,
Clear coating process 16] In the top coating process of the car body drawing board, the equipment will be as shown in the plan layout shown in Figure 3.

That is, in the figure, 30° 31, 32, 33 is a general purpose or multi-arm type with an electrostatic painting gun attached to the wrist end;
Alternatively, it is a dedicated industrial robot, 34.35 is a reciprocator for painting the main parts of the vertical and horizontal surfaces of the car body, 36 is a reciprocator for clear painting for metallic painted cars, 3γ, 3B, and 39.40 are respectively This is a clear painting robot.

In the conventional process of this kind, the outer panel was first painted with a reciprocator, and then a person applied the corrective paint to the areas that could not be sufficiently painted with the reciprocator, but in this example, this person The robot does the work that was being done30.
31, 32, and 33.

Further, the painting by the robot 30° 31, 32, 33 is performed before the painting by the reciprocators 34, 35, etc.

Note that the robots 30, 31, 32, and 33 each hold the right and left sides of the car body, respectively, and the robot 30, 32 holds the cross-marked part of the car body C shown in FIG.
3 is in charge of the part marked with * in the figure.

Of course, most of the remaining parts are due to the reciprocator.

The reason why the robot 30, 31, 32, and 33 painted the local area first is as follows.

In other words, in the case of painting by a robot, it is preferable that the relative positional relationship with the vehicle body be as constant as possible, but this is difficult to satisfy in the case of a system using a continuous conveyor.

In order to satisfy this requirement, the robot is moved together with the vehicle body to reduce the relative speed between the two to zero or small, but in such a case, it is necessary to provide moving equipment on the robot side as well.

In addition, the robot may be fixed and the vehicle body used as a tact conveyor.

In any case, it is necessary to provide various equipment around the robot, and in this case, if the robot is located in the center of the topcoating process line, it will require an extremely large amount of space to accommodate the reciprocator and the like.

By positioning the robot at the end of the line, the space required for the line can be reduced compared to the above case.

As with the intermediate coating process mentioned above, the introduction of robots can save labor and reduce environmental equipment.

After passing through these steps, the vehicle body determined to be defective in the inspection step 15 is returned as shown by the broken line in FIG. 1, and this step is performed again.

In the above description, an automobile body was used as an example of the object to be coated, but electrical products and the like can also be similarly subjected to the above-mentioned pretreatment.

As explained above, the pretreatment method for painting according to the present invention is a pretreatment step in which the surface of the object to be coated is cleaned with a mixed solution of a degreaser, brightener, etc., before pretreatment steps such as degreasing and chemical conversion treatment. By setting , it is possible to remove oil, dust, etc. from the surface of the object to be painted, increase the gloss of the heritage so that it is suitable for inspection, and easily discover unevenness and scratches on the surface of the object to be painted before applying the paint. This makes it possible to reliably correct surface defects before forming a coating film, thereby improving the quality of the coating surface and preventing obstruction of the flow of the object to be coated.

[Brief explanation of drawings]

Figure 1 is a block diagram of the painting method using this invention, Figure 2 is a block diagram of the painting method using this invention.
The figure is a conceptual diagram of electrodeposition washing, FIG. 3 is a schematic plan view of the top coating process line, and FIG. 4 is a perspective view showing the painted parts of an automobile body. 1... Temple treatment (preliminary cleaning) process, 2...
・Correction process, 3...Pre-treatment process, 4...
・Electrodeposition process, 5...Electrodeposition washing process, 8...
...Exterior panel intermediate coating process, 9...Internal top coating process, 10
...Door installation process, 12...Top coating process, 13...Reciprocator painting process, 14.
...Robot painting process.

Claims (1)

[Claims] 1. A preliminary treatment step of pre-cleaning the surface of the object to be coated with a mixed solution of a degreaser and a brightener, a step of repairing the pre-treated object to be coated, and at least a chemical conversion treatment and washing of the object to be coated that has been corrected. A pretreatment method for painting, comprising the steps of: