JP2819183B2 - Solder chip and manufacturing method thereof - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a soldering tip such as a soldering iron tip for an electric soldering iron or a soldering tip for an automatic machine and a method for manufacturing the same. The present invention relates to a solder chip having high productivity and good yield and a method for manufacturing the same.

(Prior Art) Solder chips such as an iron tip of an electric soldering iron are required to have good thermal conductivity and excellent solder wettability, and usually satisfy these requirements. Copper is used as a material.On the other hand, copper has a disadvantage that it is inferior in corrosion resistance to solder and flux, and when the entire tip is formed only of copper, it is used in continuous soldering work etc. In addition, there is a problem that the tip is reduced at an early stage due to the erosion effect of solder or flux, and the life is relatively short. This problem was particularly remarkable in a precision soldering tip having a tip diameter of 1 mm or less.

Therefore, conventionally, as shown in FIG. 8 (c), an iron plating layer b having excellent corrosion resistance is formed on the entire surface of the copper base a by 50 to 50%.
A structure having a thickness of about 500 μm was generally used.

In manufacturing this tip, first, it is formed into a chip shape of a copper base a (FIG. 8 (a)), and then an iron plating layer is formed on the entire surface (FIG. 8 (b)). ,
The raised portion b 'of the iron plating layer at the corner such as the tip of the tip is removed by surface finishing such as turning using a lathe to obtain a product as shown in FIG. 8 (c). Incidentally, the raised portion b 'of the iron plating layer is a result of an increase in the current density at each corner of the copper base a due to the fact that the iron plating process is performed for a long time in the electrolytic process. This portion had to be removed because the material was hard and brittle, which was undesirable in terms of molecular structure.

However, in such a manufacturing method, since the thickness of the iron plating layer b cannot be checked from the outside, even if the surface contour is formed by the machining described above, even if the surface contour is formed in an expected shape, the iron plating The thickness of the layer b varies, which causes a problem that uniform corrosion resistance cannot be imparted to the product.

Also, when manufacturing a small-diameter chip with a tip diameter of 1 mm or less, such as a soldering tip for precision soldering work, for example, 250 mm
In order to apply an iron plating layer b having a thickness of μm, the tip diameter of the copper base a must be formed to be 0.5 mm or less. It is extremely difficult to manufacture and in practice,
Mass production was impossible.

In this regard, recently, as shown in FIG. 9 (a), first, after forming a round bar-shaped copper base c having a spherical tip, an iron plating layer d is formed on this surface. A chip base as shown in FIG. 9 (b) is formed, and finally this chip base is subjected to forging (swaging and pressing) to obtain an intended product shape as shown in FIG. 9 (c). A molding method has been developed (for example, Japanese Patent Publication No. 59-11).
No. 386).

According to this method, since the tip portion of the copper base c serving as the tip end of the chip has a spherical shape, it is possible to form the iron plating layer d having a uniform thickness. The thickness can be made uniform to some extent, and high-quality products can be manufactured with good yield.

(Problems to be Solved by the Invention) However, this manufacturing method also has the following problems, and further improvements have been demanded.

(1) In order to ensure sufficient performance as a corrosion-resistant chip, the thickness of the iron coating formed on the surface of the copper base c is
It is desirable that the thickness be at least 250 μm or more. However, if this iron film is formed according to the conventional technique (Japanese Patent Publication No. 59-11386), there is a problem in productivity.

That is, in the electrodeposition of iron metal, the deposition thickness of iron when 1 A / dm ² is applied is a value of the cathode current efficiency of 100%, 13.25 μm / hr for Fe ²⁺ ions, and 8.83 μm / hr for Fe ³⁺ ions. hr.
Therefore, in order to obtain the iron plating layer b having a thickness of 250 μm or more as described above, a long time of one day and night is required, and the productivity is extremely low.

(2) In addition, it is very difficult to accurately analyze the amounts of Fe ²⁺ ions and Fe ³⁺ ions contained in a normal iron plating solution, and thus the amounts of Fe ²⁺ ions and Fe ³⁺ ions. It is extremely difficult to control the plating solution so as to always maintain the same ratio, and the productivity is also low in this respect.

In addition, if the plating solution management is insufficient, the hardness of the iron plating layer d applied to the surface of the copper base c may increase, and this may cause the iron plating layer to be hardened when the soldering iron is heated. Cracking or peeling may occur.

(3) Further, in the method in which forging such as swaging is performed after the formation of the iron plating layer d, the thickness of the electrodeposited iron plating layer d cannot be measured accurately after the plating process is completed, and the deformation due to forging pressure is caused. Due to this, it is unavoidable that the thickness of the iron plating layer d becomes somewhat uneven.

Therefore, even with this method, it is unavoidable that the quality of the finished product will be uneven, and it is actually very difficult to control the thickness of the iron plating layer in the product and supply the product with the desired quality. Met.

The present invention has been made in view of such conventional problems, and provides a solder chip excellent in corrosion resistance, long in life, extremely easy to manufacture and excellent in productivity, and a method for manufacturing the same. The purpose is to:

(Means for Solving the Problems) In order to achieve the above object, a method for manufacturing a soldering chip according to the present invention covers an iron tip member having a Vickers hardness of a predetermined value or less on a tip portion of a copper substrate having a step. Shape and integrally fixed, the outer peripheral surfaces of both are flush and continuous, then the tip of the base body to which the iron chip member is fixed,
After forming by drawing into a predetermined shape by forging processing such as swaging processing, and providing an intermediate layer in consideration of the case where the outermost layer is peeled off, as the outermost layer, the boundary portion between the iron chip member and the copper base body A solder plating layer is formed on the tip side, and a chrome plating layer is formed on the other portions.

Further, the solder chip of the present invention is manufactured by the above method.

(Function) A metal material having excellent thermal conductivity and excellent corrosion resistance to solder, flux, etc., for example, a thin chip member made of iron, for example, is provided on the tip portion of the base which comes into contact with solder or flux during soldering work. Since it is integrally fixed in the form of a coating, the copper base having poor corrosion resistance is effectively protected from erosion by solder or flux without impairing its function.

Further, in manufacturing the solder chip, the chip member is fixedly and integrally fixed to the tip portion of the base by means such as press-fitting or brazing, and thereafter,
This tip portion is formed into a desired shape by forging processing such as swaging processing, so that plating processing such as iron plating is not required.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a soldering tip according to the present invention. Specifically, the soldering tip 1 is an iron tip of an electric soldering iron for precision soldering work, and includes a base 2 a of a copper base 2. Have a cylindrical shape, and the front portion 2b has a stepped tapered shape having a sharp tip. Further, the front end portion of the front portion 2b is covered with a tip member 3 made of iron, and a pure iron plating layer 4 is formed on the entire periphery of the base 2 so as to cover it. Further, on the surface of the pure iron plating layer 4, a solder plating layer 6 is formed so as to cover a tip end portion of the boundary portion 5 between the chip member 3 and the base 2, and hard chromium plating is applied to other portions. Layer 7 is formed.

The chip member 3 is a thin member that protects the copper base 2 from erosion by solder or flux.
Is fixedly and integrally to the tip portion of the cover.
As the constituent material of the tip member 3, iron as shown in the illustrated example is optimal, but in addition, a metal material satisfying the following conditions can be used. In other words, the conditions required for the constituent material of the chip member 3 include (a) excellent thermal conductivity, (b) good solder paste, and (c) corrosion resistance to solder and flux. And (d) it is relatively soft (micro Vickers hardness of 200 or less) like copper as the material of the substrate 2.

Pure iron plating layer (micro Vickers hardness 200 or less) 4
Is formed mainly in consideration of the case where the solder plating layer 6 and the chromium plating layer 7 are peeled off, which promotes the soldering to the tip of the base 2 and the copper ground surface of the base 2 during heating. Acts to prevent oxidation of

The chromium plating layer 7 formed on a portion other than the solder plating layer 6 is for preventing the solder from rising, and in addition, a coating treatment such as heat-resistant coating or ceramic coating is also suitable.

Next, a method for manufacturing the soldering tip (iron tip) 1 configured as described above will be described.

A copper base 2 processed into a shape as shown in FIG. 2 is formed. That is, the copper base 2 is formed in a cylindrical round bar shape, and the tip 2c is formed in a stepped spherical shape (or conical shape).

Press-fitting or brazing is applied as a fixing means for integrally fixing the iron chip member 3 to the front end portion 2c of the base 2 in a covering shape.

The tip member 3 has a thin cap shape as shown in FIG. 3, and is formed by pressing an iron material by pressing, machining, or the like.
The tip 2c has the same size as the step of the stepped portion 8 of the tip 2c, and the inner peripheral surface 3a has a shape matching the outer peripheral surface 9 of the tip 2c. As a result, in a state where the chip member 3 is fixed to the base 2, the outer peripheral surface 3b of the chip member 3 and the outer peripheral surface 10 of the base 2 are continuous with each other as shown in FIG.

The front portion 2b of the base 2 is subjected to a forging process such as a swaging process, and a tapered shape at the tip is preformed toward the tip as shown in FIG.

The front portion 2b of the preformed base 2 is further subjected to forging such as swaging, as shown in FIG.
The rear part of the front part 2b is formed into a more narrowed shape (step processing with a small diameter).

As shown in FIG. 7, the tip of the front part 2b on which the small diameter stepping is performed is cut obliquely 11 as shown in FIG.
Form a sharp tip shape according to the purpose, up to mm or more.

A pure iron plating layer is formed on the entire surface of the substrate 2 formed into a desired shape.

Further, a solder plating layer 6 is coated and formed on a portion on the tip side of the boundary portion 5 between the chip member 3 and the base 2,
The other portion is covered with a chrome plating layer 7 to form the first portion.
Complete the product shown in the figure.

(Effects of the Invention) The present invention has the following effects.

(1) Since only the tip of the chip necessary for the soldering operation is made of a metal having excellent corrosion resistance, a copper base having poor corrosion resistance is
It is effectively protected from erosion by solder and flux without impairing its function (thermal conductivity) at all, and has a long life.

(2) In addition, the life of the soldering iron chip can be freely controlled by appropriately setting the thickness of the chip member, and a structure having a structure corresponding to the work purpose can be easily and reliably provided. It can be manufactured and its quality can be easily made uniform.

(3) Since the coating layer at the tip of the base is formed by the chip member, a manufacturing method that does not require plating as in the manufacturing method of the present invention becomes possible, and a conventional manufacturing method that requires plating is essential. Can all be solved.

(4) In addition, it is possible to ensure higher wettability with the solder at the tip end of the chip, and it is possible to reliably protect other portions from erosion by solder or flux.

(6) By setting the thickness of the chip member in advance, it is possible to easily and surely form a corrosion-resistant coating layer having a uniform and desired thickness without variation at the tip of the base.

Therefore, compared with the conventional coating process using iron plating, it is possible to impart much more uniform and excellent corrosion resistance to the product, and the manufacturing time is reduced by the plating process (almost day and night). It is much shorter than that and its productivity is extremely high.

(7) After the chip member is integrally fixed to the base, the desired tip shape is formed by forging, so that the tip diameter is 1 mm, like a tip for precision soldering work.
Even when manufacturing the following small-diameter chips, the tip of the chip can be reliably molded, and it is easy to manufacture and has a good yield.
It is also suitable for mass production, and can significantly reduce production costs.

(8) There is no need for complicated and precise work management such as iron plating, and in this respect, productivity is high, and the hardness of the plating layer is increased due to insufficient plating solution management. As a result, when the soldering iron is heated, there is no problem that the corrosion-resistant coating layer at the tip of the chip is cracked or peeled off.

(9) Even if forging processing such as swaging is performed, the thickness of the chip member does not change due to this, and the thickness can be kept uniform to the initially set dimensions, so that the quality of the finished product varies. In this respect, the yield is good and the product value is high.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an iron tip of an electric soldering iron which is an embodiment of a soldering tip according to the present invention, and FIGS. 2 to 7 are views for explaining a method of manufacturing the iron tip. 8 (a) to 8 (c) are views for explaining a conventional method for manufacturing a soldering iron tip, and FIGS. 9 (a) to 9 (c).
FIG. 5 is a view for explaining another conventional method for manufacturing a soldering iron tip. 1 ... Soldering chip (iron soldering iron), 2 ...
Substrate, 3 ... chip member, 4 ... pure iron plating layer, 5 ...
Boundary part between chip member and base, 6 solder plating layer, 7
...... Chrome plating layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 3/02

Claims (2)

(57) [Claims] An iron chip member having a Vickers hardness of not more than a predetermined value is coated and integrally fixed on a stepped end portion of a copper base to make the outer peripheral surfaces of the both flat and continuous. The tip portion of the base body to which the iron tip member is fixed is drawn into a predetermined shape by forging such as swaging, and after forming an intermediate layer in consideration of the case where the outermost layer is peeled off, the outermost layer is formed. A solder plating layer on the tip side of the boundary between the iron chip member and the copper base, and a chromium plating layer on the other portion. Method. 2. An iron chip member having a Vickers hardness of not more than a predetermined value is coated and integrally fixed to a stepped end portion of a copper base to make the outer peripheral surfaces of the two flat and continuous. The tip portion of the base body to which the iron tip member is fixed is drawn into a predetermined shape by forging such as swaging, and after forming an intermediate layer in consideration of the case where the outermost layer is peeled off, the outermost layer is formed. Characterized in that the solder plating layer is formed by coating a solder plating layer on the tip side of a boundary portion between the iron chip member and the copper base, while coating a chromium plating layer on the other portions. For chips.