JPS5926670B2 - Degreasing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a degreasing method, and particularly to a method that can improve and make uniform the degreasing effect on the surface of a workpiece having a complex shape.

The metal surface of the workpiece is covered with an oxide film during manufacturing and subsequent processing, and is also contaminated with oil, fat, lint, dirt, etc. that adheres during machining.

Unless this dirty surface is cleaned to reveal a clean base, it will be unsuitable for later plating, chemical conversion treatment, painting, etc. If plating or painting is applied to a dirty surface, the adhesion will be poor. Therefore, durability cannot be obtained. For this reason, degreasing treatment has traditionally been carried out to remove various oily substances adhering to the metal surface prior to operations such as plating, chemical conversion treatment, and painting. The degree of cleaning, in other words the quality of the degreasing effect, has a great impact on the quality of the final product.

For example, the quality of the phosphate film formed by phosphate treatment, which is one of the chemical conversion treatments, is of course affected by the temperature of the phosphate treatment tank, the chemical solution, the treatment liquid flow rate conditions, etc. It has been recognized that surface cleaning is sensitive to the degree of cleaning. By the way, methods for performing such degreasing generally include a spray method in which a predetermined degreasing liquid is sprayed onto the object to be treated, and a full-dip method in which the object to be treated is immersed in the degreasing liquid. .

In the former method of degreasing using a spray method, for example, as shown in FIG. Transferred to process B, and then washed with water process C
After that, it is subjected to surface conditioning and phosphate treatment, but when the object to be treated is a complex-shaped object such as an automobile body, the inner plate or bag-like part of the object to be treated is There was a concern that the degreasing liquid could not be sufficiently sprayed onto the materials, and therefore the degreasing effect would not be sufficient and the food resistance would deteriorate.
In addition, when the object to be treated is a car body, the spray treatment is carried out in the second
The treatment will be performed in the state shown in the figure, but the distance from the spray nozzle 4 arranged so as to surround the vehicle body 3 to the surface of the object to be treated (3) varies, and if the treatment is performed with the same spray pressure, There was also a problem that the degreasing effect on the surface of the object to be treated (3) differed depending on the location, and as a result, it became impossible to achieve uniform quality. On the other hand, in the latter degreasing method using the full immersion method, as shown in FIG. The object to be treated is immersed and degreased (B)
Then, the water washing process C1 is followed by surface conditioning and phosphate treatment, whereby each part of the object to be treated is brought into even contact with the treatment liquid (degreasing liquid). However, the substances adhering to the surface of the object to be treated cannot be effectively removed simply by contacting the treatment liquid.

For this reason, conventionally, a predetermined flow is applied to the degreasing liquid in the degreasing tank 6, but the degreasing effect by the flow rate of the degreasing liquid alone has not sufficiently solved the above problem, and especially For objects to be processed that have complex shapes, it is necessary to take some countermeasures. Here, the present invention has been made in view of the above circumstances, and is directed to the surface and inner plate of a workpiece having a complex shape such as that of an automobile.
It is an object of the present invention to provide an effective method for improving the degreasing effect of bag-shaped areas and the like, and also for making the effect uniform.

In order to achieve such an object, the present invention combines degreasing treatment of a workpiece with a complicated shape that is continuously transported with a spray treatment step of spraying a predetermined degreasing liquid onto the workpiece. The process is carried out in combination with a full immersion treatment process in which the object to be treated is immersed in the same type of degreasing liquid as that used in the spray treatment process, and in the spray treatment process, a spray nozzle for spraying the degreasing liquid is connected to the target object. The spray pressure of the degreasing liquid from the nozzle is set according to the distance between the nozzle and the surface of the object to be treated.

In addition, in the present invention, it is preferably employed that the transition time between the spray treatment step and the full immersion treatment step is within 30 seconds. The reason why the interval between the two processes is set within 30 seconds is that if the time from one treatment process to the other exceeds 30 seconds, the surface of the object to be treated may dry out, and This is because rust occurs in some parts, the degreasing agent adheres, and the degreasing liquid dries and flows unevenly, making the subsequent phosphate treatment etc. uneven.
Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 4 shows the basic process for chemical conversion treatment of a workpiece having a complex shape such as a vehicle.The workpiece 10, which is moved in the direction of the arrow It is immersed in the tank 11 to receive the hot water washing treatment, and then transferred to the degreasing treatment step B according to the present invention.

In this degreasing process B, first, a predetermined degreasing liquid is sprayed onto the object to be treated 10 by an appropriate spraying means 12, and a spray treatment is performed.

Next, the spray-treated workpiece 10 is completely immersed in the degreasing liquid in the degreasing liquid tank 13 within 30 seconds after the spray degreasing treatment to undergo full immersion (full date-free treatment). By combining these methods, more complete and uniform degreasing can be achieved.In other words, dirty degreasing liquid remains on the surface of the workpiece 10 that has been spray degreased in the previous spray treatment, for example, on the horizontal indoor surface. Or
Alternatively, the inner plate and bag-shaped portion of the object to be treated 10 may not be sufficiently degreased, but such problems can be resolved by bringing the entire body into contact with the degreasing solution in the next full immersion treatment. It will be done. In general, the degreasing mechanism in the degreasing process is different from the chemical reaction between the steel plate and a chemical solution, such as phosphate treatment, and is merely cleaning the surface of the steel plate with the degreasing liquid. A certain degree of pressure is required for the degreasing liquid on the surface of the object 10, and this is the main reason why spray degreasing treatment and full immersion degreasing treatment are combined.
That's why. Note that the order in which the spray degreasing treatment and the total immersion degreasing treatment are combined and the number of steps are not limited to the example shown in FIG. 4, and there is no problem in the order shown in FIG. 6. .

That is, in FIG. 6, the spray treatment process and the full immersion treatment process are reversed from those in FIG. is now being implemented.
In addition, the spray treatment in the degreasing process B is as follows:
Specifically, for example, as shown in FIG.
Spray piping 21 to 25 arranged so as to surround 0
This is carried out by spraying a predetermined degreasing liquid from spray nozzles 26 to 30 provided in the respective areas.

However, the distance from the spray nozzles 26 to 30 to the surface of the workpiece 10 varies, and if all nozzle blowing pressures (spray pressures) are constant, the distance from the spray nozzles 26 to 30 to the surface of the workpiece 10 is
10 horizontal surfaces such as loops 14 and hoods 15 and doors 16
The degree of degreasing on vertical surfaces such as Also, if the pressure of the degreasing liquid sprayed on the floor back 17 is too strong, it may cause damage to the holes in the floor back 17, such as the transmission mounting hole 18.
Dirty degreasing liquid may enter from the bottom of the engine room or the engine room, and adhere to the back of the loop inside the room or the back of the hood, or the dirty degreasing liquid may accumulate on the floor (19), which can easily lead to a decline in quality. . As mentioned above, these problems can be solved by the subsequent full immersion treatment, but in order to further enhance the effect and to make the spray treatment uniform, the present invention further uses a degreasing liquid. The spray pressure of the degreasing liquid from the nozzles 26 to 30 is appropriately set according to the distance between the spray nozzles 26 to 30 that spray the degreasing liquid and the surface of the workpiece 10.

FIG. 5 clarifies an example of setting the spray pressure according to the distance to the surface of the object to be treated.

The under-floor spray nozzle 26 and the under-floor local spray nozzle 27, which are close to the surface of the object to be treated, each have under-floor spray piping 2.
Low-pressure degreasing liquid is supplied from the degreasing liquid tank 20 through the pipes 1 and 22 for local spraying on the floor by low-pressure pumps P, P2, and is blown out under low pressure. A medium-pressure degreasing liquid is supplied to the vertical surface spray nozzle 28 and the horizontal surface local spray nozzle 29 located at the vertical surface spray piping 23 and the horizontal surface local spray piping 24 by medium-pressure pumps P3 and P4, respectively. A high-pressure degreasing liquid is supplied by a high-pressure pump P5 through a horizontal spray pipe 25 to the spray nozzle 30, which is sprayed under a medium pressure and further away from the surface of the object to be treated, and the degreasing liquid is supplied at a high pressure toward the surface of the object to be treated. The degreasing liquid is sprayed using spray pressure. This made it possible to perform spray degreasing more uniformly. According to the studies conducted by the present inventors, the spray pressure at the nozzle outlet (y: I<9/Cl
In relation to the distance (X; CTIl) between the spray nozzle and the surface of the object to be treated, ii) is generally desirable to be within a range that satisfies the formula: Each spray pressure (nozzle outlet) is determined accordingly.

The optimum degreasing effect is achieved within this spray pressure range. The object to be treated 10 that has undergone the degreasing treatment step B consisting of the spray treatment and the total immersion treatment according to the present invention is then washed with water (C
), and after being subjected to a known surface conditioning treatment using a total immersion method (9), it is immersed in the intended treatment tank and subjected to phosphate treatment, thereby forming a predetermined phosphate film on the surface. However, as described above, the surface of the object to be treated 10 is more completely and uniformly degreased according to the present invention, so that the quality of the phosphate film is improved and Therefore, it became possible to effectively improve corrosion resistance.

As described above, the present invention combines a spray treatment method and a total immersion treatment method in the degreasing treatment process so that the object to be treated can be transferred between the two processes preferably within 30 seconds,
In addition, by using the same type of treatment liquid, the spray pressure (blowout pressure) from the spray nozzle in spray degreasing treatment in such a combination can be set in accordance with the distance from the nozzle to the surface of the object to be treated. Therefore, more complete and uniform degreasing is performed, thereby increasing the degreasing effect.
Furthermore, the improvement of the surface quality of the final treated object is of great industrial significance.

In addition, although the above example described the degreasing treatment in the phosphate treatment step, the present invention is not limited to this in any way, and is suitably applied to degreasing treatment in other surface treatment steps.

Further, even in the case of a combination method of spray treatment and full immersion treatment, a method of controlling spray pressure, etc., the above-mentioned examples are the most desirable and effective ones, but as long as they do not depart from the spirit of the present invention. Other methods and techniques that can be devised based on the knowledge of those skilled in the art may also be adopted as appropriate.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing a degreasing process using a spray method, FIG. 2 is a schematic cross-sectional view of the spray degreasing process, and FIG. 3 is a process diagram showing a degreasing process using a total immersion method. FIG. 4 is a process diagram of a phosphate treatment step showing an embodiment of the present invention, and FIG. 5 is a schematic enlarged cross-sectional view of the spray degreasing step. FIG. 6 is a diagram corresponding to FIG. 4 showing another embodiment of the present invention. 1, 2: Spray 1, 3:
Object to be treated, 4: Spray nozzle, 5: Hot water washing tank, 6: Degreasing liquid tank, 10: Processing object, 11: Hot water washing tank, 12: Spray means, 13: Degreasing liquid tank, 20: Degreasing liquid tank , 21-2
5: Spray pipe, 26-30: Spray nozzle.

Claims (1)

[Claims] 1. When a predetermined degreasing process is continuously performed on a workpiece having a complicated shape, the degreasing process is combined with a spray treatment step in which a predetermined degreasing liquid is sprayed onto the workpiece. ,
The treatment process is performed in combination with a full immersion treatment step in which the object to be treated is immersed in the same type of degreasing liquid as that used in the spray treatment step, and in the spray treatment step, a spray nozzle for spraying the degreasing liquid and the object to be treated are combined. A degreasing method characterized in that the spray pressure of the degreasing liquid from the nozzle is set according to the distance between the nozzle and the surface. 2. At least two degreasing liquid pipes and a pump means are provided, and degreasing liquid under different pressures is guided through the piping to a predetermined spray nozzle, and the degreasing liquid is spouted from the nozzle with a spray pressure corresponding to the distance. 2. A method according to claim 1, wherein said spraying treatment is carried out by applying said spray treatment. 3. The method according to claim 1 or 2, wherein the transition between the spray treatment step and the full immersion treatment step is performed within 30 seconds.