JPH0488192A - Method and apparatus for partial plating - Google Patents

Abstract

PURPOSE:To carry out partial plating at a low cost by means of mass treatment by electroplating the whole surface of a material to be treated with plating layer having the desired physical properties and then removing the plating layer from the part requiring no plating by means of reverse electrolysis. CONSTITUTION:Degreasing treatment for a material 1 to be treated made of low carbon steel is rapidly carried out. Subsequently, the material 1 to be treated is striked, if necessary, and then immersed into a plating bath 2 to undergo electroplating. Subsequently, the part, requiring no plating, of the material 1 to be treated in which a thick-coated plating layer 3 is formed on the whole surface by the above procedure is immersed into a peeling solution 4, and the plating layer 3 is removed from this part by means of reverse electrolysis.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for selectively plating a workpiece, and more specifically, to a part that can be selectively plated with good adhesion. This invention relates to a plating method and apparatus.

[Conventional technology]

Conventionally, in order to partially apply thick plating to a workpiece, the workpiece 100 is degreased, as shown in FIG. 9(a) to fdl.
After pretreatment such as washing with water (FIG. 9(a)), masking rubber 101 formed according to the shape of the object to be processed 100 is pressed onto the parts not to be plated, and the state shown in FIG. Then, the entire body was immersed in plating solution 102 and electroplated.
The plating layer 103 is formed only on desired areas by removing the plate and performing post-processing such as washing with water (FIG. 9(d)).

However, the work of attaching and detaching the masking rubber to the workpiece is
This process is all done manually, which is time-consuming, and a large number of masking rubbers must be manufactured each time depending on the shape of the object to be processed, resulting in high costs. Furthermore,
When thick plating is applied to a workpiece, flakes are formed at the boundaries of the plating layers, causing peeling of the plating layers.

It is also possible to perform electroplating by immersing only the parts that require plating in the plating solution without masking the object, but in order to form a uniform plating layer, it is necessary to The concentration must be kept constant by constant stirring, but stirring causes the liquid level to fluctuate, making the boundary between areas that require plating and areas that do not need to be plated uncertain, and the plating solution may adhere to the surface or the object to be treated. As a result, the desired plating process cannot be performed.

[Problem to be solved by the invention]

In view of the above-mentioned situation, the present invention aims to solve the problem by forming a plating layer with desired physical properties on the entire surface of the workpiece without using masking rubber, which was previously essential, and then plating the parts that do not need plating. It is an object of the present invention to provide a partial plating method and an apparatus therefor, which can perform mass processing by removing layers and can reduce costs.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention established a partial plating method in which a plating layer with desired physical properties is formed on the entire surface of the workpiece by electroplating, and then the plating layer in unnecessary parts is removed by reverse electrolysis. did.

More specifically, after the object to be treated is immersed in a plating solution and a plating layer with desired physical properties is formed on the entire surface by electroplating, only unnecessary parts are immersed in a stripping solution to remove the plating layer on that part. We have established a partial plating method that removes the metal by reverse electrolysis.

In addition, we have an electroplating device that forms a plating layer with desired physical properties on the entire surface of the workpiece by immersing the workpiece in a plating solution and setting the workpiece as the negative electrode. Immerse it in a stripping solution whose liquid level has been adjusted to a constant level,
A partial plating apparatus was constructed, which consisted of a reverse electrolyzer that removed the plating layer on the immersed area by reverse electrolysis with the object to be treated as the positive electrode.

Here, the reverse electrolysis device has a horizontal upper edge spaced apart from the side walls and lower than the height of the side walls, inside the container main body, which is provided with conductive guide strips serving as positive electrodes on the upper edges of both side walls. A partition wall is provided to form a processing tank filled with a stripping solution, a mesh-like electrode serving as a negative electrode is installed horizontally inside the processing tank, and the stripping solution overflowing from the upper edge of the partition wall is drained between the partition wall and the side wall. While keeping the water level of the stripping solution constant by supplying it to the bottom of the treatment tank through the drainage channel with a pump, a conductive jig for holding the object to be treated is installed between the guide strips, and It is preferable to move the jig in the direction in which the jig extends.

Further, a preliminary tank was provided to store the stripping solution overflowing into the drainage channel, and the stripping solution in the reserve tank was supplied to the bottom of the processing tank using a pump.

Furthermore, the jig has sliding parts placed on the guide strips on both sides of the support rod, and the support rod has a holding piece or a magnetic material to be processed that elastically presses the inner or outer surface of the object to be processed. A plurality of attachment parts each having a permanent magnet or an electromagnet that attracts objects are provided to facilitate attachment of objects to be processed.

Further, in the jig, the height of the sliding part can be adjusted.

[Effect]

The partial plating method of the present invention having the above-mentioned contents forms a plating layer with desired physical properties by electroplating on the entire surface of the workpiece for which plating technology has been established, and then removes only the unplated parts in a stripping solution. The metal and other materials constituting the plating layer are eluted and removed by immersion and reverse electrolysis. At this time, there is no need to stir the stripping solution, making it possible to accurately adjust the liquid level.

In addition, a reverse electrolytic device removes the plating layer from unnecessary parts of the workpiece that has a plating layer with desired physical properties formed on the entire surface.
The stripping solution overflowing from the upper edge of the partition wall of the processing tank provided inside the container body is supplied to the bottom of the processing tank through a drainage channel between the partition wall and the side wall using a pump, and is circulated. Since it is set horizontally, the liquid level of the stripping solution is always kept constant, and a jig holding the object to be processed is placed on the guide strips provided on the upper edge of both side walls of the container body, and then the processing tank is opened. By using the mesh-like electrode inside as a negative electrode and the object to be treated as a positive electrode, a current is supplied and the object is moved in the direction in which the guide strip extends, thereby performing reverse electrolytic treatment in sequence.

In addition, by providing a reserve tank to store the stripping solution overflowing into the drainage channel, and supplying the stripping solution from the reserve tank to the bottom of the treatment tank using a pump, the stripping solution can be managed and purified in the reserve tank. This is easy to do, and the stripping solution can be replenished even during processing.

Furthermore, the jig is easy to attach to the container body because the sliding parts on both sides of the support rod are placed on the guide strips of the container body and moved in the direction in which the guide strips extend. At the same time, it is easy to attach the workpiece to the jig. In particular, when an electromagnet is used, the processed object can be removed by cutting off the current supplied to the electromagnet.

Furthermore, by adjusting the height of the sliding part of the jig, the size of the part of the workpiece that requires plating can be adjusted, and workpieces of different sizes can also be handled.

〔Example〕

Next, the present invention will be further described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 shows a conceptual diagram of the partial plating method of the present invention.
Figure 18) shows the pre-treatment process for the object to be treated 1, Figure 1 (Figure 1) shows the plating process for the entire surface, Figure 1 (C) shows the partial peeling process, and Figure 1 (d+ shows the post-treatment process). There is.

In this example, a short tube made of low carbon steel is used as the object to be treated 1, and thick copper plating is applied to the inner and outer surfaces of the short tube, with a boundary along the circumference only at one end in the axial direction. Give an example.

The workpiece 1 of this embodiment is to be welded to another member using this thick copper plating, so the plating part must have good adhesion to the workpiece 1. It won't happen.

Pretreatment Step (Fig. 1(a)) Since low carbon steel is a material that rusts easily and is weak to acids, it is necessary to perform degreasing treatment promptly. In this example, trichlorethylene treatment (immersion, heper treatment, drying treatment)
After that, an alkaline cleaning with good permeability is performed using an activator, and after sufficient water washing, a next rust prevention treatment is performed. Then, electrolytic degreasing is performed using an automatic machine to complete the degreasing.

Plating process (Figure 1 (bl)) This process is further divided into two processes, the first of which is a base plating process (W1 strike process), and the second process is a thick copper plating process. The entire surface of the object 1 to be treated is subjected to plating treatment.

In the copper strike treatment as well, the thickness of the workpiece 1 and the copper are important steps that determine the adhesion between the workpiece 1 and the copper.

The conditions of this copper strike bath are shown in the table below.

Table 1: Copper Strike Bath Next, in the thick copper plating process, after complete activation and base strike treatment, a two-step activation process is performed before starting the main plating process. The first step is the removal of the oxide film in the air during strike treatment or the water washing step, and the second step is to equalize the pH before entering the plating bath. The main plating process is performed by electroplating using a plating bath containing copper cyanide, copper sulfate, or copper birophosphate as a main component. Figure 1 (b
) 2 indicates a plating solution, and 3 indicates a plating layer formed on the surface of the object to be processed 1. The concentration of the plating solution 2 is kept constant during processing by using stirring, convection, or the like. Further, the thickness of the plating layer 3 is set to be 15 μm or more on the outer surface of the tip.

Partial stripping process (Fig. 1 (C)) The unplated part of the workpiece 1 on which the thick copper plating layer 3 was formed on the entire surface in the previous process is immersed in the stripping solution 4, and this part is removed by reverse electrolysis. The plating layer 3 is removed.

This stripping liquid 4 is used to elute copper ions constituting the plating layer 3 when reverse electrolysis is performed with the object 1 set as the positive electrode. 360g/j! The peeling process is performed at a current density of 5 to 8 A/dm and at a normal plating temperature. At this time, the plating conditions must be accurately controlled so that the plating layer 3 is completely eluted and the material of the object 1 to be treated is not eroded. Also,
Setting of parts that do not require plating or parts that require plating is to be done on object 1.
This is done depending on the relative position between the surface of the stripping liquid 4 and the surface of the stripping liquid 4. Therefore, it is necessary to accurately control the liquid level of the stripping liquid 4.

Post-treatment step (FIG. 1(d)) After the object to be treated 1 is extracted from the stripping solution 4, the pH is adjusted and the object is sufficiently washed with water to obtain a final product. In this case, rust prevention treatment shall be applied as appropriate. As a result, as shown in FIG. 1(d), a plating layer 3 is formed on the inner and outer surfaces of the workpiece 1 only at one end in the axial direction, with the circumference as the boundary.

The present invention comprises a method and apparatus for applying thick copper plating to the entire surface of a workpiece 1, and a method and apparatus for removing the plating layer 3 in areas where no plating is needed. , the partial peeling method and device require the following improvements.

That is, accurate control of the liquid level of the stripping liquid 4 and special measures for mass processing are required.

In the present invention, a reverse electrolyzer A shown in FIGS. 2 and 3 is used in this peeling process.

The reverse electrolyzer A is provided with conductive guide strips 7, 7 serving as positive electrodes on the upper edges of both side walls 6.6 of the container body 5.
A partition wall 8.8 is erected from the bottom surface 9 at a position spaced apart from the side wall 6 inside the processing tank 10 to form a processing tank 10. A preliminary tank 14 in which the stripping liquid 4 overflowing from the upper edge 11 of the partition wall 8 into the drain channel 12 is temporarily stored through the drain pipe 13. The stripping solution 4 in the preliminary tank 14 is supplied to the supply pipe 1.
5 and a suction pump 16 from the bottom surface 9 of the processing tank 10, and the stripping liquid 4 is circulated through the processing tank 10, the drainage channel 12, and the preliminary tank 14. In addition, the above-mentioned guideline 7.
A conductive jig 17 is installed across the opening 7, and the workpiece 1 electrically connected to and attached to the jig 17 is used as a positive electrode, and a mesh-shaped electrode 18 placed horizontally in the processing tank 10 is used as a negative electrode. power supply 1
9 to perform reverse electrolysis.

The jig 17 has sliding parts 21.21 on both sides of the support rod 20 that are placed on the guide strip 7 and move, and the support rod 20 has mounting parts 22 for attaching the workpiece l at regular intervals. There are multiple rows. Then, when both sliding parts 21.21 of the jig 17 are placed on the guide strip 7.7 with the workpiece l attached to the mounting part 22, only the desired part of the workpiece l The mounting portion 22 is attached from the liquid level so as to be immersed in the stripping liquid 4.
The height can be adjusted. For example, a structure in which an adjustment plate of a certain thickness can be laminated on the lower surface of the sliding part 21,
A structure is adopted in which the sliding portion 21 can be moved up and down at the end axis with respect to the ground plate.

More specifically, examples of the mounting portion 22 of the jig 17 are shown in FIGS. 4 to 8.

The mounting part 22 shown in FIG. 4 is provided with a plurality of needle-shaped holding pieces 24 that are elastically biased outward on a substrate 23 placed below a support rod 20, and the holding pieces 24 are attached to It is supported by pressing against the inner surface.

The mounting portion 22 shown in FIG. 5 and FIG.
Or a protrusion 2 that can be directly fitted into the support rod 20 into the workpiece l.
5 is fixed, and a plurality of band-shaped holding pieces 24 are provided around the protrusion 25 and elastically biased inward.Since the protrusion 25 is fitted into the workpiece 1, the MfR of the workpiece 1 is fixed. It is possible to install it in the specified position without any doubt. Note that the shapes of the holding pieces 24 in FIGS. 5 and 6 are different.

The mounting section 22 shown in FIG. 7 is provided with a permanent magnet 26 that attracts the workpiece l made of a ferromagnetic material to the substrate 23 or directly to the support rod 20.

If the permanent magnet 26 does not have electrical conductivity, an electrode plate made of aluminum or copper is laminated on the surface that attracts the object 1 to be processed.

The mounting section 22 shown in FIG. 8 is provided with an electromagnet 27 that attracts the workpiece 1 made of a ferromagnetic material to the substrate 23 or directly to the support rod 20. In this case, the processed object 1 can be easily removed by cutting off the current supplied to the coil 28 of the electromagnet 27.

Therefore, the plating layer 3 is formed on the part of the workpiece 1 that does not require plating, with the plating layer 3 formed on the entire surface based on FIGS. 2 and 3.
To explain the process for removing the
Since the stripping liquid 4 is constantly circulated and overflows from the upper edge 11 of the partition wall 8 into the drain channel 12, the liquid level in the drain channel 12 is always maintained at approximately the same level as the upper edge 11 of the partition wall 8. . In this state, the jig 17 with a plurality of objects 1 attached to the mounting part 22
The sliding portions 21, 21 of are positioned on one side of the processing tank 10 and placed on the guide strips 7, 7. At this time, only the portions of the object to be treated 1 that are not required to be plated are immersed in the stripping liquid 4, but the volume increase caused by this is drained into the drainage channel 12 in the same manner as described above, and the liquid level is kept constant again. Therefore, from the power source 19 to the guide line 7
When an electric current is passed through the jig 17 to the workpiece l, which becomes the positive electrode, the copper constituting the plating layer 3 located in the stripping solution 4 becomes copper ions, or when it is composed of other materials. The material is eluted as positive ions, reaches the mesh-like electrode 18 which becomes the negative electrode, receives and takes electrons from the electrode 18, and is deposited to form an electrochemical circuit leading to the power source 19.

Then, the jig 17 with the other workpiece 1 attached is placed in the processing tank 1.
0 on the guide strip 77 in the same manner as described above, and push out the previous jig 17 in the direction in which the guide strip 7 extends.
By repeating this, the jig 17 sequentially moves forward.

Finally, the jig 17 in the front row from which the plating layer 3 on the unnecessary portions has been completely removed is recovered, and each workpiece 1 is removed.

〔Effect of the invention〕

The partial plating method and apparatus thereof of the present invention as described above has the following effects.

According to claims 1 to 3, after forming a plating layer with desired physical properties on the entire surface of the workpiece for which plating technology has been established by electroplating, only the parts not to be plated are immersed in a stripping solution to perform reverse electrolysis. Since the metals and other materials that make up the plating layer are eluted and removed, conventional masking rubber is completely unnecessary, and mass processing is possible, reducing costs.Moreover, the stripping solution is stirred during the process. Since there is no need to do this, the liquid level can be adjusted accurately, and the boundary between areas that require plating and areas that do not require plating can be set with high precision.

According to claim 4, the stripping solution overflowing from the upper edge of the partition wall of the processing tank provided inside the container body is supplied to the bottom of the processing tank through a drainage channel between the partition wall and the side wall and circulated. ,
Since the upper edge of the partition wall is set horizontally, the processing tank was formed by installing a partition wall inside the container body without having to monitor the liquid level and automatically supply or remove excess or insufficient stripping liquid. With a simple structure, the level of the stripping liquid can be kept constant at all times. In addition, a jig holding the object to be processed is placed across guide strips provided on the upper edges of both side walls of the container body, and similar jigs are sequentially supplied and moved in the direction in which the guide strips extend. It is possible to perform reverse electrolytic treatment.

According to claim 5, a preliminary tank is provided to store the stripping solution overflowing into the drainage channel, and the stripping solution in the reserve tank is supplied to the bottom of the processing tank by a pump, so that the stripping solution is not removed in the preliminary tank. This makes it easy to manage the solution and purify it, and even during processing, it is easy to replenish the stripping solution without disturbing the liquid level in the processing tank.

According to claim 6, since the sliding parts on both sides of the support rod of the jig to which the object to be processed is attached are placed on the guide strip of the container body and moved in the direction in which the guide strip extends, It is easy to attach to the container body, it is easy to attach the object to be processed to the attachment part of the jig, and the electrical connection is reliable.

According to claim 7, since the object to be processed made of ferromagnetic material can be attached to the attachment part by magnetic attraction, the attachment is even easier, and especially when an electromagnet is used, a large number of objects after processing can be attached. The objects to be processed can be removed at the same time very easily by cutting off the current supplied to the electromagnet.

According to claim 8, by adjusting the height of the sliding portion of the jig, it is possible to adjust the dimensions of the portion of the workpiece that requires plating, and it is also possible to accommodate workpieces of different sizes. I can do it.

[Brief explanation of the drawing]

Figures 1 (al to d) are simplified sectional views showing the plating process of the present invention, Figure 2 is a longitudinal sectional view showing a reverse electrolysis device, and Figure 3
The figure is a perspective view of the main parts, FIG. 4 is a partial sectional view showing the main parts of the jig for attaching the workpiece using elastic force, and FIG. 5 is a partial sectional view showing another embodiment of the jig. , Fig. 6 is a partial bottom view showing still another embodiment of the jig, Fig. 7 is a side view of the main part of the jig for attaching a ferromagnetic workpiece using a permanent magnet, and Fig. 8 is the same. (A side view of the main parts of a jig using an electromagnet, FIG. 9 (al to (d+ are simplified cross-sectional views showing the conventional partial plating process. , 3: Plating layer, 4: Stripping liquid, 5: Container body, 6: Side wall, 7 Two guide strips, 8: Partition wall, 9: Bottom surface, 1o: Processing tank, 11: Upper edge, 12: Drainage channel, 13: Drain pipe, 14: Reserve tank, 15:
Supply pipe, 16: pump, 17: jig, 18: electrode, I9
: Power supply, 20: Support rod, 2I: Sliding part, 22: Mounting part,
237 substrate, 24: holding piece, 25: protrusion, 26: permanent magnet, 27: electromagnet, 28: coil, 100: processing object,
101: 771. King rubber, 102: plating solution,
1o3: Plating layer. Seizo Matsuda, who issued the patent, Figure 1 (b) -, z Figure (C) (d> Figure Figure 1)

Claims (1)

[Scope of Claims] 1) A partial plating method characterized by forming a plating layer with desired physical properties on the entire surface of the object to be treated by electroplating, and then removing unnecessary portions of the plating layer by reverse electrolysis. 2) After immersing the object in a plating solution and forming a plating layer with desired physical properties on the entire surface by electroplating, immerse only unnecessary parts in a stripping solution and remove the plating layer on that part by reverse electrolysis. 2. The partial plating method according to claim 1, wherein the partial plating method is performed by removing the plating layer. 3) An electroplating device that forms a plating layer with desired physical properties on the entire surface by immersing the workpiece in a plating solution and electroplating with the workpiece set as the negative electrode, and an electroplating device that forms a plating layer with desired physical properties on the entire surface of the workpiece. A partial plating device comprising a reverse electrolytic device that removes a plating layer on the immersed portion by immersing the object in a stripping solution whose liquid level is adjusted to a constant level and using reverse electrolysis with the object to be treated set as the positive electrode. 4) The reverse electrolysis device has a partition wall that is spaced apart from the side walls and has a horizontal upper edge lower than the height of the side walls inside the container body, which has conductive guide strips serving as positive electrodes on the upper edges of both side walls. is installed to form a processing tank filled with a stripping solution, a mesh electrode serving as a negative electrode is installed horizontally inside the processing tank, and the stripping solution overflowing from the upper edge of the partition wall is drained between the partition wall and the side wall. While keeping the water level of the stripping solution constant by supplying it to the bottom of the processing tank through the channel with a pump, a conductive jig for holding the object to be treated is placed between the guide strips, and 4. The partial plating apparatus according to claim 3, wherein the jig is moved in the extending direction. 5) A reserve tank is provided to collect the stripping solution overflowing into the drainage channel,
5. The partial plating apparatus according to claim 4, wherein the stripping solution in the preliminary tank is supplied to the bottom of the processing tank by a pump. 6) The jig has sliding parts placed on the guide strips on both sides of the support rod, and the support rod has a plurality of mounting parts each having a holding piece that elastically presses the inner or outer surface of the workpiece. 5. The partial plating apparatus according to claim 4, further comprising: a partial plating apparatus according to claim 4; 7) The jig has sliding parts placed on the guide strips on both sides of the support rod, and the support rod is provided with a plurality of mounting parts each having a permanent magnet or an electromagnet that attracts the magnetic material to be processed. The partial plating apparatus according to claim 4. 8) The partial plating apparatus according to claim 6 or 7, wherein the height of the sliding portion of the jig is adjustable.