JP3202161B2 - Surface treatment method for small parts and apparatus used for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment, and more particularly to a method for partially treating a small electronic component with a high degree of positional accuracy, such as plating, and an apparatus used for the method. It is.

[0002]

2. Description of the Related Art FIG. 4A is a perspective view of a plating apparatus 10 used in a conventional surface treatment method, and FIG.
It is BB sectional drawing in (A). For example, when partially plating the contact member 20 of the connector, FIG.
As shown in FIG. 3A, the contact member 20 is immersed in a plating solution 28 to be plated. The boundary between the plating part and the non-plating part can be controlled by the position of the plating solution 28 liquid level. In the case of FIG. 4 (A), the contact member 20 is shown as a continuous one,
0 may be for each contact. FIG.
In (A) and (B), reference numeral 22 denotes an electrode for plating. Usually, the surface of the plating solution 28 wets the surface of the contact member 20 at a wetting angle θ31 due to surface tension as shown in FIG. The wetting angle θ3 in this case
Although 1 is a constant, the angle θ31 changes depending on the surface state (presence or absence of dirt, oil, oxide film) of the contact member 20, the type of plating solution, the solution temperature, and the like.

[0003]

In recent years, there has been a strong demand for miniaturization of connectors as well as electronic equipment components (eg, ICs). That is, miniaturization of the connector
It is essential to reduce the size of the contacts. Even with a small contact having a length of about 5 mm, the contact portion may be gold-plated and the tail portion may be solder-plated. In this case, for the purpose of preventing the molten solder from flowing beyond the tail portion of the contact to the contact portion (gold plated portion) during soldering when mounting the connector on the circuit board, A nickel plating part is provided between a plating part and a solder plating part to divide into three parts of gold, nickel and solder. Conventionally, the plating boundary is generally controlled by the level of the plating solution 28. However, the level of the liquid is reduced by discharging the liquid flowing out of the filter of the plating liquid circulation circuit used to keep the plating liquid clean, stirring the plating liquid to increase the plating speed, and contacting the contact member with the plating liquid. The liquid level fluctuates up and down due to the impact of folding or unloading, and this causes ripples, which degrades the positional accuracy of the boundary of the partial plating. Further, as described above, the liquid surface of the plating solution 28 wets the surface of the contact member 20. The wet-up height depends on the thickness and width of the contact member 20, the type of plating solution, the viscosity, etc., but is conventionally about 0.5 to 2 mm, and the positional accuracy of the boundary of the partial plating is controlled within this range. It was difficult. In particular, in the case of a small contact material consisting of three parts of gold, nickel and solder, it is difficult to control the level of the plating solution and partially plate in a predetermined section.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a plating method for a small contact, which can reduce the waving of the liquid surface, reduce the wetting height that rises due to surface tension, and increase the positional accuracy of the plating boundary. It is an object of the present invention to provide a surface treatment method suitable for the method and an apparatus used for the method.

[0005] The purpose of this is to arrange the plate-like member horizontally at a position close to the object to be processed, and to make the state in which the lower surface of the plate-like member is in contact with the surface of the plating solution, or by the surface tension. This can be achieved by raising the liquid level in contact with the lower surface of the member.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of the method according to the present invention is as follows. A plate-like member is horizontally arranged on a surface of an object to be processed, at a position close to the object to be processed, and The method is performed in a state where the lower surface is in contact with the surface of the plating solution 28, or the plating solution is brought into contact with the lower surface of the plate member by surface tension. There are, for example, the following three methods for bringing the plating solution surface into contact with the lower surface of the plate member by surface tension. After bringing the lower surface of the plate member into contact with the liquid surface, the plate member is pulled up in that state.・ Immerse the lower end of the object in the plating solution with the object in contact with the plate member.・ Waves the liquid surface to bring the wave front into contact with the lower surface of the plate member.

[0007] The apparatus used in the above method includes a plate-like member arranged at a position close to the object to be treated, a reinforcing plate for reinforcing the plate-like member, and a high-pressure plate in which the object to be treated is immersed in a plating solution. A fixing tool having a slit having a width larger than the width of the workpiece and a through-hole through which a plating solution can flow is integrally connected and fixed to a plating tank. In addition, the plate-shaped member and the reinforcing plate may be manufactured integrally. The slits of the plate-like member may be a plurality of slits into which a workpiece is inserted. The plate-like member may have a plurality of holes corresponding to the number of the workpieces, instead of the plurality of slits. In addition, instead of the slit, the plate-shaped member is provided with a concave portion having a size into which an object to be processed can be inserted, the plate-shaped member is rotated by a roller, and the other plate-shaped member is fixed. The object to be processed may be sandwiched between the shaped members.

When the plate-like member is brought closer to the object to be processed, the surface of the plating solution adheres to the bottom surface of the plate-like member due to surface tension and is lifted. The wetting angle θ31 in FIG. 1B is a constant determined by the type of the liquid, the liquid temperature, and the like, and when the object to be processed is sandwiched by a thin plate, the wetting height 32 becomes the original wetting height in FIG. Only the tip of the rod 32 remains. Therefore,
The wetting height based on the plate member can be reduced. Also, since the liquid surface other than the position lifted by the plate member is located below, even if the liquid surface moves up and down due to waving, the position of the liquid surface hardly changes by contacting the lower surface of the plate member. The effect on the plating boundary can be reduced. Also, the smaller the gap between the workpiece and the plate-shaped member, the smaller the wet-up height 32. The object to be processed is the contact member 20.

According to the method of the present invention, two plate-like members 12 are provided.
Are arranged in a state of being approached to the contact member 20 as much as possible, and the contact member 20 is moved between them. The distance between the plate member 12 and the contact member 20 is 0.1 to 0.8 mm in consideration of the position accuracy of the partial plating, the accuracy of the surface of the plate member, and the thickness of the contact member 20 by reducing the wetting height 32. Is desirable. For example,
When the thickness of the contact member 20 is 0.2 mm, 0.5 to 0.8
mm is desirable. Apparatus using this surface treatment method,
When the thickness of the plate member 12 is, for example, as small as 0.2 mm, the reinforcing plate 14 is bonded to the opposite side to the liquid surface with an adhesive, and the fixing member 16 is screwed in the liquid surface to be integrated with the plate member 12. It is fixed. This integrated unit is fixed to the plating tank by screws. This integrated unit is provided with means for vertically moving the plate member 12 in order to raise the liquid level. In consideration of the parallelism of the plate member 12, this means is generally performed by adjusting the height of a bar screw which is screwed to both ends of the reinforcing plate 14 and whose lower end is in contact with the plating tank or the like up and down. It is a target.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective view of a plating apparatus for a small contact 20 using the surface treatment method of the present invention,
FIG. 2B is a sectional view taken along line BB in FIG. Generally, an electrode 22 and the like for plating are installed in the plating tank 10. Reference numeral 20 denotes a contact member to be plated. Reference numeral 12 denotes plate members 12 arranged on both sides in the plate thickness direction of the contact member 20 in order to reduce the wetting height 32 and reduce the influence of waving of the liquid surface. One end of the plate member 12 is in contact with the contact member 2.
0 (R) or chamfer (C
It is better to do with imitation). The plate-like member 12 has a width of 35.
mm, the length is about 200 mm, and the thickness is about 0.2 mm. However, if the thickness of the plate member 12 is large,
Is thinner, since the portion facing the surface is shielded and plating is difficult to arrive. When the plate-shaped member 12 is thin, it tends to be deformed due to warpage or distortion and cannot maintain a horizontal plane. In this case, the reinforcing member 14 is attached to correct the horizontal plane. Examples of the material of the plate member 12 include plastics such as acrylic resin and polyvinyl chloride resin, metals such as stainless steel coated with insulating paint, ceramics, and the like. In this case, ceramic is preferable in consideration of dimensional stability such as strength and warpage.

Although the plate-like member 12 and the reinforcing plate 14 are formed as separate parts in this embodiment shown in FIG. 1, they may be formed integrally.
The reinforcing plate 14 has a width of 30 mm in consideration of the role of reinforcement.
And the length is about 200 mm and the height is about 10 mm.
Examples of the material of the reinforcing plate 14 include plastics such as acrylic resin, metals such as stainless steel, and ceramics.

Reference numeral 16 denotes a fixture 16 for positioning the plate-like member 12 and attaching the plate-like member 12 to the reinforcing plate 14. The fixing member 16 includes the contact member 2.
One or a plurality of through-holes 18 are provided in the slit 24 through which the "0" is inserted, and the side surface so that the plating solution 28 can flow. The slit 24 also has a role of positioning a portion (immersion portion 26) on which the contact member 20 is plated. That is, the lower surface of the contact member 20 is
4 is positioned by contacting the bottom surface. The size of the fixture 16 is 80 mm in width and 200 mm in length.
And the height is about 25 mm. The width of the slit 24 of the fixture 16 is 0.2 m larger than the thickness of the contact member 20.
The height should be such that the bottom surface of the contact member 20 is in contact with the slit 24. Examples of the material of the fixing member 16 include plastics such as polyvinyl chloride resin and acrylic resin, metals such as stainless steel, and ceramics. Ceramics are preferable in consideration of wear resistance due to sliding with the contact member 20.

The reinforcing plate 14, the plate member 12, and the fixture 16 are integrally connected by a known technique such as screwing. This integrally connected member is fixed to the bottom or side surface of the plating tank 10 by screws or the like so that the position of the plate member 12 does not change. By fixing the integrated unit to the plating tank 10, the position of the plate-shaped member 12 does not fluctuate due to the influence of the liquid surface waving or the like.

In the present invention, the shape of the plate member 12 may be such that a plurality of slits 24 are provided near the center of the plate as shown in FIG. Multiple slits 2
By providing 4, the contact members 20 of a plurality of strips can be plated simultaneously. Alternatively, a plurality of holes 34 may be formed in the plate member 12 as shown in FIG. The contact members 20 are inserted into the holes 34 one by one.
, A plurality of contact members 20 can be plated at the same time. FIG. 3 shows a configuration in which a chain of contact members 20 at a constant interval is conveyed by four holding rollers 40, and the contact members 20 are sandwiched between two plate members 12. The plate-like member 12 as one endless loop is provided with a concave portion 36 at the same interval as the contact members 20 so that the plate member 12 can be rotated by a roller (not shown) in the same direction as the conveying direction of the contact member 20. . The other flat plate-shaped member 12 is fixed. In nickel plating with sulfamic acid bath,
Plate-like member 12 having a plate thickness of 0.2 mm and a slit interval of 0.5 mm
Is used for a contact member having a plate thickness of 0.25 mm and a width of 1.0 mm and when not used, the fluctuation range of the liquid level is as shown in Table 1. As a result, it is possible to reduce the waving of the liquid surface, to reduce the wetting height that swells due to surface tension, and to regulate the positional accuracy of the plating boundary. can do.

[0015]

According to the present invention, the liquid surface is covered with the liquid surface in contact with the lower surface of the plate member 12 to eliminate the waving of the liquid surface, and by bringing the end surface of the plate member 12 closer to the contact 20, Of the liquid surface raised along the surface of the contact member 20 due to the surface tension, the area approaching the plate member 12 is flatly pressed by the lower surface of the plate member 12, thereby making it possible to narrow the range in which the liquid rises. The wetting height can be reduced accordingly.

[Brief description of the drawings]

FIG. 1A is a perspective view of an apparatus using the method for treating a small contact surface of the present invention. (B) It is BB sectional drawing in (A).

FIG. 2A is a plan view of a modified example of the plate member according to the present invention. (B) It is a top view of the modification of the plate-shaped member which is this invention.

FIG. 3 is a plan view of a modified example of a plate-shaped member according to the present invention using a roller.

FIG. 4A is a perspective view of an apparatus using a conventional contact surface treatment method. (B) It is BB sectional drawing in (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plating tank 12 Plate-shaped member 14 Reinforcement plate 16 Fixture 18 Through hole 20 Contact member 22 Electrode 24 Slit 26 Dipping part 28 Plating solution 30 Screw hole 32 Wetting up height 34 Hole 36 Depression 38 Flange 40 Flange 40 Holding roller

Claims (8)

(57) [Claims] 1. A surface treatment method for immersing a part of a processing object in a processing liquid, wherein the plate member is horizontally arranged at a position close to the processing object,
A surface treatment method for a small component, wherein the method is performed in a state where the lower surface of the plate member is in contact with the surface of the treatment liquid. 2. The method for treating a surface of a small component according to claim 1, wherein the plate-like member is brought closer to the object to be treated by 0 or 3 mm or less. 3. The method for treating a surface of a small component according to claim 1, wherein the liquid surface in contact with the lower surface of said plate-like member is raised by surface tension. 4. The surface of a small component according to claim 3, wherein the liquid surface of the processing liquid is raised by bringing up the plate member after bringing the lower surface of the plate member into contact with the liquid surface. Processing method. 5. A plate-like member which is horizontally arranged at a position close to the object to be processed and comes into contact with the surface of the processing liquid, a reinforcing plate for reinforcing the plate-like member, and a height at which the object to be processed is immersed in the processing liquid. A fixture having a slit wider than the plate thickness of the workpiece and a through-hole through which the processing liquid can flow, and a reinforcing plate, a plate-like member, and a fixture are integrally connected, and this integrated product is fixed to a processing tank. devices using that the surface treatment method of claim 1, wherein. 6. The apparatus according to claim 5, wherein a slit for inserting a plurality of workpieces is provided in said plate-shaped member. 7. The apparatus according to claim 5, wherein the plate-like member is provided with a number of holes corresponding to individual workpieces. 8. A horizontal arrangement at a position close to an object to be processed.
Providing two plate-shaped members that are in contact with the surface of the processing liquid , and providing a recess having a size that allows an object to be processed to be inserted into one of the plate-shaped members,
3. The surface treatment method according to claim 1, wherein the plate-like member is rotated by a roller, and the other plate-like member is fixed, and the workpiece is sandwiched between the two plate-like members. Equipment to do.