JPH04143290A - Surface treatment - Google Patents

Abstract

PURPOSE:To drastically shorten working time and to execute the surface treatment of a blind hollow article by putting a cap having a fluid introducing port in the aperture of the blind hollow article made of a metal, etc., and subjecting only the outer side face thereof to a surface treatment then forcibly feeding fluid from the introducing port and removing the gap. CONSTITUTION:The gap 11 is constituted of the cap body 12 and the gas introducing pipe 13 mounted through this body 12. This cap 11 is hermetically mounted in the aperture of the blind hollow article 1 molded of a metal or synthetic resin, etc. This blind hollow article 1 is immersed in a plating liquid and is plated only on the outer side faces; thereafter, gas, such as air, is force fed under 0.1 to 3kg/cm<2> (gage pressure) into the hollow part 15 of the blind hollow article 1. The cap 11 is then removed from the blind hollow article 1. The surface treated product 1 is subjected to good plating treatment in this way without sticking flaws, stains, etc., thereto.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides surface treatment such as plating to a bottomed hollow product made of metal or synthetic resin, etc., when the outer surface of the bottomed hollow product is This invention relates to a surface treatment method in which a surface treatment such as plating is applied only to the surface of the surface, thereby preventing scratches, dirt, etc. from adhering to the surface-treated product and making the work easier.

[Prior art] In the case of normal plating, the entire surface to be plated must be immersed in the plating liquid, but as shown in Fig. When single-sided plating 2 is applied only to the side surface, some method must be used to prevent the plating from depositing on the main part of the plating.

Such a method is generally called partial plating, and the conventional methods of partial plating include masking the main part of the plating with masking agent 3 as shown in FIG. 6, or as shown in FIG. A method of forming an object to be plated with an outer member 4 made of a material that can be plated and an inner member 5 made of a material that can be plated (Japanese Patent Laid-Open No. 62-1330
81, Japanese Patent Application Laid-open No. 58-93890), or as shown in Fig. 8, sealing with a cap 6 or the like to prevent the plating liquid from infiltrating and preventing the plating liquid from contacting the inner surface. ing.

[Problems to be solved by the invention] However, in the case of the method of masking, the process requires time and labor, and the plating finish deteriorates at the boundary between the masking area (the boundary between the area that requires plating and the area that does not require plating). Sometimes. Further, the masking agent may or may not be used depending on the type of plating liquid, and the masking agent may peel off due to poor masking and the plating may be deposited on important parts of the plating. Furthermore, there are disadvantages in that the masking agent cannot be reused and the plating solution becomes dirty due to dissolution of the masking agent.

On the other hand, when the object to be plated is formed using a different material in the second method, the material cost and molding cost are high, and although it is effective for objects to be plated made of synthetic resin, it is not suitable for metal objects. It was not suitable.

In addition, the method of attaching the cap is the simplest, but when removing the cap, you have to touch the plated product, which may cause scratches, dirt, etc. on the plated product, and it is also very difficult to remove the cap. There was a problem that required a lot of effort.

This invention was made in view of the above circumstances, and prevents scratches, dirt, etc. from adhering to the product when surface treatment such as plating is applied only to the outer surface of a bottomed hollow product made of metal or synthetic resin. The purpose of this invention is to provide a surface treatment method that is easy to work with.

[Means for Solving the Problems] The present invention provides a method in which a bottomed hollow product made of metal or synthetic resin is capped with a cap having a fluid inlet at the opening thereof, and then
The above-mentioned problem was solved by applying surface treatment only to the outer surface of the product, and then, after the surface treatment was completed, fluid was pressurized into the bottomed hollow product through the fluid inlet and the cap was removed.

[Specific structure of the invention] The present invention will be explained in detail below.

Plating will be explained as an example of the surface treatment according to the present invention.

FIG. 1 is a diagram showing an example of a cap used in the surface treatment method according to the present invention, and the symbol 11 in the figure is the cap. The cap 11 includes a cap body 12 and a cap body 12.
It consists of a gas introduction pipe 13 that is attached to penetrate through the. The cap body 12 is a disk-shaped thing made of chemical-resistant and elastic synthetic rubber or elastic resin, and is part of it. A through hole I4 is formed here.

The gas introduction pipe 13 is attached to pass through the through hole 14, and the space between the gas introduction pipe 13 and the through hole 14 is fixed with an adhesive or the like.

As shown in FIG. 1, such a cap 11 is firmly attached to the bottomed hollow article l to be plated so as to tightly close the opening thereof.

In this way, when the bottomed hollow article 1 is immersed in the plating solution with the cap 11 attached, the inner surface will not come into contact with the plating solution, and only the outer surface can be plated.

Next, after plating is completed, open the gas inlet 1 of the gas inlet pipe 13.
32L, an inert gas such as air or nitrogen is pressurized into the hollow part 15 of the bottomed hollow article l. Due to the gas being pressurized, the pressure inside the hollow part 15 of the bottomed hollow article 1 increases,
Push up the cap 11. At this time, the amount of the above introduced gas is 0.1 to 3 kg/Cl11! The cap 11 can be removed from the bottomed hollow product 1 by press-fitting the cap 11 at a pressure of about (gauge pressure).

Furthermore, as shown in FIG. 2, performing the operation of removing the cap underwater 17 using a water tank 16 is effective in preventing damage to the plated bottomed hollow product I.

Furthermore, FIG. 3 is a schematic diagram of a device for automating and continuous operation of removing the cap after plating.

This device consists of an introduced gas storage container 19, a pressure regulator 20, a valve 21, and a gas introduction line 22. Further, as shown in FIG. 4, a universal joint 18 is attached to the gas introduction pipe 13 of the cap 11 so that it can be detachably connected to the gas introduction line 22.

After plating is completed, connect the universal joint 18 to the gas introduction line 22, and use the pressure regulator 20 to
Gas from the introduced gas storage container 19 adjusted to a pressure (gauge pressure) is forced into the hollow part of the bottomed hollow product 1 to be plated by opening and closing the valve 21, and the cap 11 is placed in the bottomed hollow product 1 under water 17 of the water tank 16. Remove from item 1.

After obtaining the first plated product in this way, the universal joint 18 is removed from the gas introduction line 22 and the cap 11 is removed.
Then, the universal joint 18 of the cap 11 of the second bottomed hollow article 1, which has been plated only on its outer surface in the same manner, is connected to the gas introduction line 22. then the second
Gas is pressurized into the hollow part of the bottomed hollow product L, and the water tank 16
Remove the cap under water at 17. In this way, the operation of removing the cap 11 from the plated bottomed hollow product l is repeated, and plated products can be obtained continuously.

In addition, filling the hollow part of the bottomed hollow product l with a liquid 23 such as water or filling it with gas and applying plating while creating a positive pressure is effective for plating materials with poor heat resistance and pressure resistance. Other effects include preventing the plating liquid from entering and reducing the amount of gas introduced.

Furthermore, in the case of plating, bubbling is sometimes performed to stir the plating liquid, but a gas for bubbling can also be used as the introduced gas. Further, for removing the cap 11, not only gas pressure but also water pressure can be used.

It goes without saying that if the cap is a tapered stopper with a reduced diameter at the tip, it will be easier to attach and detach.

Furthermore, the surface treatment method of the present invention can be used not only for plating as described above, but also for painting, electrolytic polishing, and the like.

[Example] An example of electroless N+ plating on a bottomed hollow product made of ABS resin will be shown. The electroless Ni plating method was performed by a method normally used for ABS resin.

A silicone stopper was used for the cap, a through hole was made, a nylon tube was attached as a gas introduction tube, and a joint was attached to the tip of the tube.

Next, electroless Ni plating was performed by pushing the silicone plug as hard as possible into the bottomed hollow product made of ABS resin to be plated so as not to come off during plating. At this time,
The hollow part of the ABS resin bottomed hollow product to be plated was sealed with a silicone plug, and since there was no contact between the inner surface and the plating solution, electroless Ni plating could be applied only to the outer surface.

Furthermore, after the plating was completed, the silicone stopper was removed under water in the washing tank by the following procedure.

First, connect the tube of the nitrogen gas introduction line to the joint at the end of the gas introduction tube, and while the object to be plated is immersed in water, introduce nitrogen gas from the gas pump at a pressure of 0.2 kg/em'. The silicon plug was removed from the object to be plated using the pressure of nitrogen gas.

A with electroless Ni plating only on the outer surface using the above method.
It was possible to obtain a bottomed hollow product made of BS resin.

The thus obtained Metsuki ABS resin hollow product with a bottom is
There were no stains or scratches on the outer surface, and the surface was beautifully finished. In addition, the cap could be removed instantly, and productivity was also good.

[Effects of the Invention] As explained above, according to the surface treatment method of the present invention, one-sided plating can be performed without using a masking agent, so the working time can be significantly shortened, and it is possible to reduce the time required for plating and the important parts to be plated. You can always get a good finish on the border.

Furthermore, since the bottomed hollow product can be formed from a single material, material costs and molding costs are reduced.

Alternatively, since the cap is removed using gas pressure, it is possible to prevent scratches, dirt, etc. from adhering to the object to be plated, and almost no effort is required.

Furthermore, since automation and continuity are possible, it also leads to improved productivity.

In addition, if the hollow part is filled with a liquid such as water, plating can be done while cooling, which makes it possible to plate materials with poor heat resistance, and is also effective for plating materials with poor pressure resistance. .

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a bottomed hollow product sealed with a cap used in the surface treatment method of the present invention, and Fig. 2 is a view showing a state in which the operation of removing the cap in the present invention is performed underwater. , Fig. 3 is a schematic diagram showing the device for removing the cap, Fig. 4 is a sectional view of the joint connected to the gas introduction pipe,
5 to 8 are sectional views showing examples of conventional methods. l...Bottomed hollow product,...Cap- ■5...Hollow part, 9...Introduced gas storage container.

Claims (1)

[Claims] After a cap with a liquid inlet is placed on the opening of a bottomed hollow product made of metal or synthetic resin, surface treatment is applied only to the outer surface, and then, after the surface treatment is completed, fluid is placed inside the bottomed hollow product. A surface treatment method characterized by pressurizing fluid through an inlet and removing the cap.