JPH0576558B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a plating method suitable for high-speed plating of rod-shaped members, in which one end of the object to be plated is inserted into a clamp hole of a carrier, The object to be plated is inserted from above into a plating chamber in which a cylindrical electrode is installed, and the plating liquid is injected into the plating chamber from the bottom and the object to be plated is plated while overflowing. After the plating is completed, the object to be plated is By pricking one end and removing the object to be plated, it is possible to automatically plate a rod-shaped member up to one end without using human hands.

"Prior art and its problems" By applying relative motion between the plating liquid and the object to be plated, the ion diffusion layer on the surface of the object to be plated is destroyed.
A high-speed plating method has been proposed in which plating is performed at high speed by flowing a large current at a low voltage.

FIG. 17 shows an apparatus for carrying out a conventional high-speed plating method, in which reference numeral 1 denotes an object to be plated, and numerals 2 and 3 denote holders for holding the object 1 to be plated. Holders 2 and 3 are coaxially provided,
One holder 3 has a piston rod 4 coaxially attached to it.
are installed in succession. In normal standby mode,
The holders 2 and 3 have been moved to the outside of the plating unit 5 (to the left in the figure) and are facing each other with a line for conveying the object 1 to be plated in between. In this standby state, the piston rod 4 is in the plating chamber 6.
penetrates through.

When the object to be plated 1 is transported from the previous process,
The holders 2 and 3 in the standby state approach each other, and both ends of the object to be plated 1 are fitted into the insertion recesses 2a and 3a. Thereafter, the object to be plated 1 is placed in the holder 2,
3 in the axial direction and accommodated in the plating chamber 6. The plating liquid is flowing into the plating chamber 6 as shown by arrow A in the figure, and penetrates through the electrode 7 that forms part of the peripheral wall of the plating chamber 6 and one of the holders 2 that holds the object 1 to be plated. Then, the object to be plated 1
Perform the metsuki.

In the conventional plating method carried out by such an apparatus, both ends of the object 1 to be plated are fixed by the holders 2 and 3, so there has been a complaint that both ends of the object 1 to be plated cannot be plated at all.

"Means for Solving the Problem" Therefore, in the plating method of the present invention, one end side of the object to be plated is inserted into a clamp hole of a carrier having a penetrating clamp hole, and the object to be plated held in the clamp hole is One electrode is brought into contact with one end of the object, and the object to be plated is inserted from above into the plating chamber where the other cylindrical electrode is installed, and the plating liquid is injected into the plating chamber from the bottom and overflows. Apply plating to the object to be plated,
After the object to be plated is removed from the plating chamber after plating, one end of the object to be plated is poked to remove the object, thereby solving the above problem.

"Operation" According to this plating method, one end of the object to be plated is held by a carrier and the object to be plated is inserted from above into the plating chamber in which the plating liquid is allowed to flow so as to overflow. The other end of the object can be brought into contact with the plating liquid, and the peripheral surface and the other end of the object to be plated can be simultaneously plated at high speed.

"Example" Hereinafter, the plating method of the present invention will be explained in detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a schematic configuration of an apparatus for carrying out an embodiment of the plating method of the present invention, and the reference numeral 1 in the figure shows
0 is a liquid storage tank. This plating liquid storage tank 10
The plating liquid stored in the plating unit 12 is circulated by the pump 11, and
It is circulated between the filter 13 and the filter 13.

The object to be plated 14, which is the object of the plating method of the present invention, has a substantially rod-like outer shape, and may include, for example, a substantially cylindrical pin as shown in FIG.

In this plating method, the object to be plated 14 is transported to the plating unit 12 using a carrier 20 as shown in FIG.

The carrier 20 has a penetrating clamp hole 21...
and electrodes 22 exposed in the clamp holes 21..., and is formed of a main body plate 20a, a conductor plate 20b, and a pressing plate 20c which are laminated in sequence. The main body plate 20a is a portion that holds the object to be plated 14 and is made of an insulating material such as an acrylic plate. The clamp hole 21 is formed by ring-shaped rubber gaskets 24, 24 inscribed in the blind hole 23, a hollow portion of the spacer 25, and a hole 26 bored at the bottom of the blind hole 23. . The rubber gaskets 24, 24 are formed to have an inner diameter that can securely hold the object 14 to be plated.

The conductor plate 20b supplies electricity to the object to be plated 14, and is made of a conductive material such as a phosphor bronze plate. As shown in FIGS. 4 and 5, the electrode 22 portion of the conductor plate 20b is composed of four leaf-shaped electrodes 22a formed by square-shaped slits 27. slit 27
The intersection of the horizontal bar and the vertical bar at the center of the square is located at the center of the clamp hole 21, and this part is formed into a round hole 27a of a size through which a push-out rod, which will be described later, can easily pass through. ing. This conductor plate 20b
is closely fixed to the main body plate 20a by a holding plate 20c.

When the object to be plated 14 is inserted into the clamp hole 21 of the carrier 20 from one end, the electrode 2 is exposed.
One end of the object to be plated 14 is in contact with the conductor plate 20
electrically connect to b. At this time, since the four leaf-shaped electrodes 22a formed by the slits 27 exhibit appropriate elasticity, the object to be plated 14 and the conductive plate 20b are electrically connected well. As shown in FIG. 18, the conductor plate 20b is energized when a cathode block 51, which is vertically movably held by a cylinder 50, descends and comes into contact with the conductor plate 20b.

Object 14 to be plated inserted into clamp hole 21
is firmly held by the rubber gaskets 24, 24 and will not fall off. Moreover, one end of the inserted object 14 to be plated is reliably shielded from the plating liquid by the gasket, so that it is completely masked.

The object to be plated 14 held in the clamp holes 21 of the carrier 20 is inserted from above into a plating chamber 30 provided in the plating unit 12, as shown in FIGS. 6 to 8.

The plating unit 12 includes a liquid receiving tank 33, a lid plate 34 that closes the upper part of the tank 33, and a main body 35 provided in the middle of the tank 33.
The plating chambers 30 are formed by holes perpendicular to the main body 35. Metsuki room 3
A cylindrical electrode 31 is fitted into the upper part of 0, and is electrically connected to a conductor plate 36 laminated on the upper part of the main body part 35. The electrode 31 has a main body made of titanium, and its outer surface is plated with platinum to prevent corrosion by the plating solution. The inner diameter of this electrode 31 has a gap of 5.0
It is set to be less than mm. If this gap exceeds 5.0 mm, there is an inconvenience that the flow velocity becomes small and the plating speed decreases. The plating liquid sent from the plating liquid storage tank 10 is injected into the plating chamber 30 from the lower part and overflows from the upper opening, as shown by the arrow in the figure. The overflow plating liquid flows down into the sap tank 33, is collected, and is returned to the plating liquid storage tank 10.
The plating liquid injected into the plating chamber 30 is heated to a predetermined temperature (70° C. or higher) in the plating liquid storage tank 10. In this state, when the object 14 to be plated and the electrode 31 are energized for a certain period of time via the conductor plate 20b of the carrier 20 and the conductor plate 36 of the plating unit 12, the object 14 to be plated is plated.

The object to be plated 14 that has been plated in this way...
is held in the carrier 20 in the plating chamber 3.
After being pulled out from 0 and transported to a predetermined position,
Removed from Carrier 20. To remove the object to be plated 14 from the carrier 20, a push rod is inserted into the clamp hole 21 from the upper plate 20c side of the carrier 20 and the end of the object to be plated 14 is poked.

When high-speed plating is performed using this plating method, the plating speed is proportional to the current density as shown in FIG. When the current density is set to about 250 to 1000 A/dm ² , a high plating speed of 1 to 4 μm/sec or more can be achieved. To increase the plating speed,
It is necessary to set plating conditions that increase the current density. The current density I is given by the following basic formula (1).

I=DnFC/δ(1-α) (1) In the formula (1), D is another diffusion coefficient added to the plating solution, and the larger the diffusion coefficient, the higher the plating speed. In order to increase this diffusion coefficient D, the temperature of the plating solution is increased. As shown in FIG. 10, there is a relationship between the temperature of the plating liquid and the current density I, in which the current density increases as the liquid temperature rises. As can be seen from this graph, the increase in current density is particularly noticeable when the liquid temperature exceeds 70°C, so when performing high-speed plating,
It is desirable to set the liquid temperature to 70℃ or higher.

If the temperature of the plating solution is raised to perform high-speed plating like this, the brightener may decompose and the plating may lose its luster, so the temperature of the plating solution should be raised to 70
When performing gloss plating at a temperature higher than 0.degree. C., it is preferable to use #6 series manufactured by Eva Yugilite Co., Ltd., which has no fear of decomposition.

(1) In the formula, C is the concentration of salt added to the plating solution,
As the salt concentration increases, the current density I increases. When the salt is nickel sulfate, there is a relationship as shown in FIG. 11 between the salt concentration and the maximum current density in the high concentration region. From this graph, it can be seen that when the salt is nickel sulfate, the maximum current density can be increased to the highest value by increasing the salt concentration to 350 g/or more. However, if the salt concentration exceeds 500 g/l, the plating solution becomes highly viscous and the maximum current density tends to decrease.

In formula (1), δ is the thickness of the diffusion layer. The thinner the diffusion layer, the higher the current density I and the faster the plating speed. The diffusion layer can be made thinner by increasing the flow rate of the plating liquid in the plating portion. Figure 12 shows the relationship between the flow rate of the plating liquid and the maximum current density.From this graph, the higher the flow rate of the plating liquid, the higher the maximum current density.
It can be seen that this tendency is large up to m/s. From this, it can be seen that it is desirable to set the flow rate of the plating liquid to 1.5 m/s or more. However, as the flow rate increases, the energy required to drive the pump 11 that circulates the plating liquid increases rapidly, so it is not economically viable.
It is desirable to perform plating at a flow rate of about 1.5 m/s.

(1) In the formula, α is the ion transfer number of the metal to be plated. The larger the transference number is, the larger the current density I becomes, and the plating speed can be increased. In order to increase this transference number, as in the case of the diffusion coefficient D, the temperature of the plating solution is increased.

In formula (1), the remaining n and F are the number of discharge electrons and Faraday's constant, respectively, and both are fixed stamps.

Embodiment 2 FIG. 19 shows another example of a mechanism for energizing the object to be plated.

The carrier 20 of the device used in this embodiment is formed only from the main body plate 20a, and the electrode 22 is attached to the cylinder 50 side.

When the object to be plated 14 held in the clamp hole 21 of the carrier 20 is transported to a predetermined position,
The electrode 22 is lowered by the cylinder 50 and brought into contact with one end of the object 14 to be plated.

When the plating on the object to be plated 14 is completed, the object to be plated 14 is pulled out from the plating chamber 30, and then one end thereof is poked and removed from the carrier 20.

The plating method of this example also provides the same effects as the method of Example 1.

In the above embodiment, only the approximately cylindrical pin shown in FIG. 2 was shown as the object to be plated 14, but the approximately rod-shaped object to be plated according to the present invention includes: Other examples include a cushion rod as shown in Fig. 13, a piston as shown in Fig. 14, a tuning pin as shown in Fig. 15, and a printer roll as shown in Fig. 16.

"Effects of the Invention" As explained above, in the plating method of the present invention, one end of the object to be plated is inserted into the clamp hole of the carrier, and the object to be plated is placed inside the plating chamber in which a cylindrical electrode is installed. It is inserted from above, the plating liquid is injected from the bottom of the plating chamber, and the object to be plated is plated while it overflows. After the plating is completed, the object to be plated is removed by poking one end of the object, so no manual effort is required. It is possible to automatically plate a rod-shaped member without using it.

Moreover, in the plating method of the present invention, one end of the object to be plated is held by a carrier, and the object to be plated is inserted from above into the plating chamber in which the plating liquid is allowed to flow so as to overflow. The other end can also be brought into contact with the flowing plating liquid. Therefore, according to the plating method of the present invention, the circumferential surface and the other end of the rod-shaped object to be plated can be simultaneously plated at high speed.

[Brief explanation of drawings]

FIG. 1 is a schematic view showing a plating device suitably used to carry out an embodiment of the plating method of the present invention, and FIG. 2 is a plan view showing an example of an object to be plated.
Fig. 3 is a sectional view showing the structure of the carrier of the plating device, Fig. 4 is a perspective view showing the conductor plate constituting the carrier, Fig. 5 is a plan view showing the shape of the slit, and Figs. 6 and 7 are 8 is a partial sectional view showing the plating unit, FIG. 9 is a graph showing the relationship between current density and plating speed, and FIG. 10 is a graph showing the relationship between plating liquid temperature and current density. A graph showing the relationship, Figure 11 is a graph showing the relationship between the salt concentration of the plating solution and the maximum current density, Figure 12
The figure is a graph showing the relationship between the flow rate of the plating liquid and the maximum current density, Figures 13 to 16 are perspective views showing other examples of objects to be plated, and Figure 17 shows an apparatus for carrying out the conventional plating method. A cross-sectional view, FIG. 18 is a schematic diagram showing the configuration of the electricity supply circuit of the device used in Example 1, and FIG. 19 is a schematic diagram showing the configuration of the electricity supply circuit of the device used in Example 2. 14...Thing to be plated, 20...Carrier, 21
... Clamp hole, 22 ... Electrode, 30 ... Plating chamber, 31 ... Electrode.

Claims (1)

[Scope of Claims] 1. When plating a substantially rod-shaped object to be plated, one end of the object to be plated is inserted into a clamp hole of a carrier having a through clamp hole, and the object to be plated is held in this clamp hole. One end of the object is brought into contact with one electrode, and the object to be plated is inserted from above into the plating chamber where the other cylindrical electrode is installed, and the plating liquid is injected from the bottom into the plating chamber and is covered while overflowing. A plating method in which the object to be plated is plated, the object to be plated is pulled out from the plating chamber after plating, and one end of the object to be plated is poked to remove the object.