JPH11233228A - Manufacture of fitting type connection terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide manufacture for a fitting type connection terminal enabling to lower inserting force of the terminal with contact resistance being kept stable. SOLUTION: Furring copper plating layers 2 are formed on a base material 3 of copper or a copper alloy, further tinning layers 1 are formed on them. Then, a surface 18a opposite to a sliding surface 18b in a fitting part of a terminal is applied with laser irradiation, thereby parts of the sliding surfaces 18b, 28b corresponding to beam spots of the laser are heated by heat conduction, thus copper-tin alloy layers 4 are formed on interfaces between the tinning layers 1 and the furring copper plating layers 2. Here, if the laser irradiation is applied under the condition that the tinning layers 1 remain thin, inserting force of the terminal can be lowered with contact resistance being kept stable. Also, the sliding surface 18b in the fitting part of the terminal is not applied with the laser irradiation, consequently the contact resistance can be prevented from increasing due to melting and deformation of the tinning layer 1 on the sliding surface 18b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fitting type connection terminal used for electric wiring of automobiles, industrial equipment and the like.

[0002]

2. Description of the Related Art Conventionally, fitting type connection terminals used for connecting electric wires in electric wiring of automobiles, industrial equipments and the like have been generally plated with tin. This is intended to stably obtain a low contact resistance by breaking the surface oxide film of the tin plating by friction at the time of connecting the terminals and adhering fresh tin.

[0003] In addition, electrical wiring used for particularly important signal circuits such as an ABS (anti-lock brake system) and an air bag of a vehicle has been used with gold plated connection terminals.

[0004]

The adhesion of tin plating is caused by the low tin hardness (Vickers hardness: 40 to 80). However, the low hardness of tin causes a problem of increasing the insertion force at the time of connection. That is, when the terminals are fitted and connected, cohesive wear of the tin plating occurs, and the tin is fitted against the deformation resistance of the tin, so that the insertion force increases.

[0005] By the way, in electric wiring of an automobile or the like, a bundle of a plurality of electric wires (hereinafter, referred to as "wire harness") is generally connected by a single connector. It can be roughly estimated as a value obtained by multiplying the insertion force per unit by the number of electric wires (conventionally, generally 10 to 20 poles). Therefore, when the insertion force per terminal is high, the force required to connect the connector has a large value according to the number of wires of the wire harness.

In particular, the remarkable progress and development of car electronics in recent years has dramatically increased the number of electronic devices and CPUs mounted on automobiles, and accordingly, the number of electric wires in a wire harness has been increased, and the number of connectors has been increased (30). Pole to 40
There is also a growing demand for the ultimate goal.

However, as described above, when the connector is multipolarized, the force required for connecting the connector also increases in proportion to the number of electric wires, and the connector cannot be connected without an auxiliary mechanism such as a bolt or lever. For this reason, even if the terminal is miniaturized, the auxiliary mechanism hinders miniaturization and weight reduction of the connector.

In order to reduce the terminal insertion force, it is conceivable to reduce the contact pressure (the pressing force applied to the contact at the fitting portion). However, in this case, a stable and low contact resistance cannot be obtained. In other words, since it is difficult to reduce the insertion force of the terminal while maintaining stable contact resistance, an auxiliary mechanism is indispensable when multi-polarizing the connector, which is a factor that hinders miniaturization and weight reduction of the connector. Has become.

If gold plating is used for the connection terminal,
Even if the contact pressure is low, a low contact resistance can be obtained stably, so that the insertion force of the terminal can be reduced, and even if the connector is multi-pole, the force required for the connection does not increase significantly. Since it requires several times to several tens of times the cost as compared with plating, it is not particularly suitable for a multipolar connector.

[0010] The present invention has been made in view of the above problems, and has as its object to provide a method of manufacturing a fitting-type connection terminal capable of reducing the insertion force of a terminal while maintaining stable contact resistance.

[0011]

Means for Solving the Problems To solve the above problems, the invention of claim 1 is a method of manufacturing a fitting type connection terminal for obtaining electrical contact by fitting a male part and a female part, a) a plating step of forming a tin plating layer on the surface of at least one copper or copper alloy base material of the male component or the female component, and (b) the copper or copper alloy base on which the tin plating layer is formed. The heat treatment by laser irradiation is performed only on the fitting portion in the fitting of the material, and only the vicinity of the interface with the copper or copper alloy base material of the tin plating layer in the fitting portion is alloyed with the copper-tin alloy. Laser irradiation step.

According to a second aspect of the present invention, in the method for manufacturing a fitting type connection terminal according to the first aspect of the present invention, the heat treatment is performed by using the copper or copper alloy base material on which the tin plating layer is formed. The fitting is performed by laser irradiation on the surface opposite to the sliding surface.

According to a third aspect of the present invention, in the method for manufacturing a fitting type connection terminal according to any one of the first and second aspects of the present invention, the male component or the female component is provided in the laser irradiation step. 0.1 for only one of the mating parts
The method includes a step of leaving a tin plating layer having a thickness of μm to 0.3 μm and leaving a tin plating layer having a thickness of 0.1 μm or more only in the other fitting portion.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<A. Form of Fitting Connection Terminal> FIG. 1 is a side view of the fitting connection terminal manufactured by the manufacturing method according to the present invention, and FIG. 2 is a partially cutaway view of a connection portion of the fitting connection terminal. It is a top view.

As shown, the fitting connection terminal according to the present invention comprises a male terminal 10 and a female terminal 20. The male terminal 10 is a crimping portion 1 which is a crimping portion for crimping with an electric wire.
1 and a tab 12 which is a fitting portion of the female terminal 20. The upper and lower surfaces of the tab 12 are smooth sliding surfaces.

The female terminal 20 has a crimping portion 24 which is a crimping portion for crimping with the electric wire, and a fitting portion 25 which is a fitting portion with the male terminal 10. The fitting portion 25 has a hollow box shape and includes a tongue piece 21, an emboss 22 and a bead 23.
And inside it. Note that FIG.
FIG. 2 is a partially cutaway plan view showing the inside of FIG.

The emboss 22 is a convex member provided on the upper part of the tongue piece 21, and makes point contact with the sliding surface of the tab 12 when fitted with the male terminal 10. The tongue piece 21 has a function as a spring for applying a contact pressure, that is, a pressure for pressing the emboss 22 against the tab 12. Also bead 2
Reference numeral 3 also denotes a convex member, which comes into contact with the sliding surface opposite to the surface where the tab 12 and the emboss 22 come into contact, and receives the contact pressure applied to the tab 12 by the emboss 22.

When fitting the male terminal 10 to the female terminal 20, the tab 12 is inserted into the gap between the emboss 22 and the bead 23. At this time, one of the upper and lower surfaces of the tab 12 slides on the emboss 22 and the other slides on the bead 23.
Since the emboss 22 is in point contact with the tab 12, the sliding portion of the emboss 22 is a point, and the sliding portion of the tab 12 is a line. In the bead 23, the portion in contact with the tab 12 becomes a sliding portion as it is, and the sliding portion on the tab 12 side is a line as described above.

In the strict sense, the crimping portions 11 and 24 that are used for connection with the electric wires are wire barrels 11a and 2b.
Although it is 4a, the crimping portions 11 and 24 are crimped portions in this specification for the sake of convenience in the following description.

<B. Manufacturing method of mating type connection terminal>
A method for manufacturing the fitting connection terminal will be described. The mating connection terminal in the present embodiment is formed by tin-plating a plate-shaped strip, punching out a die from the strip, irradiating the punched die with laser, processing into the form shown in FIG. It is manufactured through the process of performing pressure bonding.

<B-1. Tin plating step> Copper or a copper alloy is used as a base material of the fitting connection terminal according to the present invention. This is because, in the fitting connection terminal according to the present invention,
This is because a later-described alloying step with tin is important, and copper or a copper alloy easily forms an intermetallic compound with tin. Hereinafter, in the present embodiment, brass (copper-zinc alloy) is used.

First, in order to enhance the adhesion of the tin plating layer, pretreatment such as cleaning of the surface of the brass plate-like strip material and removal of the oxide film is performed. In the present embodiment, the thickness of the brass strip is 0.25 mm.

Next, a 0.8 μm thick
Then, a copper base plating layer of m is formed, and a tin plating process is further performed thereon to form a tin plating layer. The tin plating layer is formed on the entire surface of both surfaces of the strip. At this time, the thickness of the tin plating layer may be 0.5 μm or more and 2.0 μm or less, and is preferably 0.8 μm or more and 1.2 μm or less. In the present embodiment, the thickness of the tin plating layer is 1.0 μm.

<B-2. Punching process> After tin plating
The die is punched from the strip. FIG. 3 is a plan view showing a plate-shaped strip made of copper or copper alloy used for manufacturing a fitting connection terminal. FIG. 3A shows a strip 19 for the male terminal 10.
FIG. 3B shows a strip 29 for the female terminal 20. The contour shapes shown in the inside of the strip members 19 and 29 are punched in a punching step, and the dies 18 and 28 are used for forming the male terminal 10 and the female terminal 20, respectively.

<B-3. Laser Irradiation Step> Next, the molds 18 and 28 punched from the strip are subjected to heat treatment by laser irradiation. FIG. 4 is a view for explaining how the fitting-type connection terminal according to the present invention is irradiated with laser.

In this embodiment, a YAG laser is used for laser irradiation.
Irradiation is performed on 8, 28. At this time, the laser irradiation is not performed on the entire molds 18 and 28, but
Laser irradiation is performed only on the portion formed as the tab 12 and the fitting portion 25 by the processing in the subsequent process. In addition, tab 12,
Rather than irradiating both surfaces of the part formed as the fitting part 25 with the laser, a sliding surface 1 having respective sliding parts
Laser irradiation is performed only on the surfaces 18a and 28a opposite to the surfaces 8b and 28b. That is, the laser irradiation is not performed on the sliding surfaces 18b and 28b of the portions formed as the crimping portions 11 and 24, the tab 12, and the portion formed as the fitting portion 25.

<B-3-1. Alloying by laser irradiation>
By performing the laser irradiation as described above, the dies 18, 2
Among the portions 8, the portion formed as the tab 12 and the fitting portion 25 is heated to increase the temperature, and the alloying between the tin plating layer formed in the portion and the base material is promoted. The change of the tin plating layer at this time will be described with reference to FIG.

Before laser irradiation, a base copper plating layer 2 is formed on the surface of a base material 3 made of brass, and a tin plating layer 1 is further formed on the surface. Then, the sliding surfaces 18b and 28b of the tab 12 and the portion formed as the fitting portion 25 are formed.
The surfaces of the sliding surfaces 18b and 28b corresponding to the laser beam spots are heated by heat transfer by irradiating the surfaces 18a and 28a on the opposite side with the laser so that the tin plating layer 1 and the underlying copper plating layer 2 A copper-tin alloy layer 4 is formed at the interface. In the present embodiment, since the tin plating layer 1 is formed on the surface of the base copper plating layer 2, it is considered that the copper of the base copper plating layer 2 contributes to the copper-tin alloying due to heating. However, the tin plating layer 1 may be formed directly on the surface of the copper or copper alloy base material 3. In this case, copper of the base material 3 and tin of the tin plating layer 1 are alloyed.

Here, the laser irradiation on the opposite surfaces 18a, 28a without directly irradiating the sliding surfaces 18b, 28b with the laser is performed based on the spot diameter of the laser beam (0.8 mmφ in this embodiment). ), The energy distribution inside is not uniform and the central portion has a high energy density. Therefore, direct laser irradiation on the sliding surfaces 18b and 28b does not promote uniform alloying, and in some cases, the surface This is because the tin-plated layer 1 melts and deforms, the shape of the contact portion of the terminal cannot be maintained, and the contact resistance increases. However, under the conditions of the present embodiment, if the laser output is larger than 4 J, the sliding surfaces 18 b and 28 b may be deformed, so the laser output needs to be 4 J or less.

The copper-tin alloy layer 4 is formed by the heat treatment by laser irradiation, and the thickness of the residual tin plating layer 1 is reduced accordingly. When the tin plating layer 1 on the sliding surfaces 18b, 28b of the fitting portion is completely changed to the copper-tin alloy layer 4, the copper-tin alloy has high resistance, and when copper appears on the surface, the copper is corroded. Also, the contact resistance of the terminal may increase. Therefore, in the present embodiment, while adjusting the laser irradiation conditions, the tin plating layer 1 on the sliding surfaces 18b and 28b is left, and
The residual thickness is controlled to reduce the terminal insertion force. Hereinafter, this technique will be described.

<B-3-2. Thickness Control of Residual Tin Plating Layer on Sliding Surface> The thickness control of the residual tin plating layer 1 on the sliding surface of the fitting portion is performed mainly from the viewpoint of reducing the insertion force of the terminal. That is, in order to stably obtain a low contact resistance, the tin plating layer 1 needs to be left, but if the tin plating layer 1 is thick, as described above, the insertion force increases due to the adhesion of tin. I do.

Therefore, in this embodiment, the apparent hardness of the contact portion of the terminal is increased by leaving the tin plating layer 1 in the range of 0.1 μm to 1.0 μm on the sliding surface of the fitting portion. And the insertion force is reduced. The inventors have conducted experiments in advance to investigate the correlation between the thickness of the residual tin plating layer and the insertion force, and used the results of the investigation experiment on the effect of reducing the insertion force by controlling the thickness of the residual tin plating layer. Will be explained.

In the experiment, the thickness of the tin plating layer at the fitting portion of the male terminal 10 and the female terminal 20 was 0.1 μm each.
１．０1.0 μm, and the male terminal 10 is
The measurement was performed by measuring the insertion force when fitting to zero. In addition,
This experiment itself was performed by adjusting the thickness of the tin plating layer during the plating process. Table 1 below shows the experimental results.

[0035]

[Table 1]

The conventional tin plating thickness of the terminal is set to 1.
Assuming 0 μm, the terminal insertion force is 0.74 kgf.
Hereinafter, the description will be continued using the conventional insertion force as a reference value.

As shown by the experimental results, the thickness of the tin plating layer 1 at the fitting portion of one of the male terminal 10 and the female terminal 20 is set to 0.1 μm to 0.3 μm, and the thickness of the other tin plating layer 1 is set to 0.1 μm to 0.3 μm.
When the thickness is 0.1 μm or more, the insertion force can be reduced by at least 10% or more (0.67 kgf or less) as compared with the reference value. That is, as the tin plating layer 1 becomes thinner, the hardness of the copper-tin alloy layer 4 affects the hardness of the fitting portion, and the apparent hardness of the fitting portion becomes higher.
And, by increasing the apparent hardness of the fitting portion, adhesion of tin plating is suppressed, and the insertion force is reduced.

Further, the inventors have confirmed by experiments that if the thickness of the tin plating layer 1 is 0.1 μm or more, the conditions required for the terminal in terms of corrosion resistance and contact resistance are satisfied.

Accordingly, in order to obtain the necessary effect of reducing the insertion force, the laser irradiation is performed so that the tin plating layer 1 on the sliding surface at the fitting portion of the male terminal 10 and the female terminal 20 remains at a predetermined thickness. Adjust the conditions. Hereinafter, as an example, when the thickness of the tin plating layer 1 of the fitting portion 25 of the female terminal 20 is set to 1.0 μm (the plating process is not performed on the female terminal 20 and the heat treatment is not performed), the male terminal 10 A method of changing the laser irradiation condition to leave the tin plating layer 1 of a predetermined thickness on the sliding surface of the tab 12 and obtain a necessary effect of reducing the insertion force will be described.

FIG. 6 shows the thickness of the residual tin plating layer 1 of the tab 12 of the male terminal 10 and the terminal insertion force when the thickness of the tin plating layer 1 of the fitting portion 25 of the female terminal 20 is 1.0 μm. It is a figure which shows the correlation with. This figure shows a part of the results shown in Table 1.

As shown in FIG. 6, in order to reduce the terminal insertion force by 10%, the thickness of the tin plating layer 1 of the male terminal 10 is set to 0.40 μm.
m, and 0.23 μm, 30
It can be seen that it is sufficient to leave each of them 0.16 μm in order to reduce%.

FIG. 7 is a diagram showing a correlation between the number of laser shots at a laser output of 3.5 J and the thickness of the residual tin plating layer 1. This figure is a result obtained from an experiment conducted in advance with the initial thickness of the tin plating layer 1 being 1.0 μm. In addition, the time of one shot in the present embodiment is 20 msec.

According to FIG. 7, in order to reduce the thickness of the residual tin plating layer 1 on the sliding surface of the tab 12 of the male terminal 10 to 0.40 μm or less (reducing the terminal insertion force by 10% or more), It can be seen that three shots should be irradiated at 3.5 J. Further, when 4 shots are irradiated at an output of 3.5 J,
The thickness of the residual tin plating layer 1 on the sliding surface of the tab 12 is 0.1 μm.
m, and the terminal insertion force can be reduced by 30% or more.

The above laser irradiation conditions are merely examples,
Laser irradiation is performed on one or both of the male terminal 10 and the female terminal 20 under various conditions according to their plate thickness and the like so that a predetermined thickness of the tin plating layer 1 is left. What is necessary is just to obtain the effect of reducing the insertion force.

<B-4. Processing Step> When the heat treatment by laser irradiation is completed, the dies 18 and 28 are processed to form the male terminal 10 and the female terminal 20 in the form shown in FIGS. At this time, the sliding surfaces 18b, 28
The molding process is performed so that b is on the surface side of the male terminal 10 and the female terminal 20, respectively.

<B-5. Crimping Step> After the above-described processing of the male terminal 10 and the female terminal 20 is completed, since the tin-plated layer appropriately remains in the fitting portion of the male terminal 10 and the female terminal 20, stable contact resistance is obtained. , The insertion force of the terminal can be reduced. On the other hand, crimped portions of the male terminal 10 and the female terminal 20 (crimped portions 11, 24)
For, since laser irradiation is not performed, alloying is not promoted between the tin plating layer and the base material.

This is because there is no need to reduce the insertion force because the crimped portion is not fitted, and it is necessary to promote alloying between the tin plating layer and the base material. The crimping part is a part for performing crimping with the electric wire, and the crimping part is based on the positive reason that the tin plating layer needs to be thickened during the crimping.

The reason among them is as described above, and the reason will be described below. FIG. 8 is a diagram illustrating a state of crimping of the electric wire L and the wire barrel 11a (FIG. 1).

As shown, an electric wire L is placed inside the wire barrel 11a, and the wire barrel 11a is fitted into a lower mold 45. Then, when the upper mold 40 is lowered, the wire barrel 11a is bent inward, and the wire barrel 11 is crimped.

During crimping, the outer surface of the wire barrel 11a is slid with respect to the upper mold 40 while being deformed. However, if the tin plating layer of the wire barrel 11a is thick, soft tin is applied to the outer surface of the wire barrel 11a. It extends thinly between the upper mold 40 and the upper mold 40 and plays a role as a lubricant. Therefore, the upper mold 40 will not be worn by the hard intermetallic compound, and there is no fear of shortening its life.

[0051] In addition, the tinning layer on the outer surface of the wire barrel 11a may be cracked due to the bending of the wire barrel 11a. However, if the soft tinning layer is thick, the crack propagates, and the base metal is cracked. It does not reach the surface. As a result, there is no possibility that the corrosion resistance is reduced due to the exposure of the base material or that the crack propagates to the base material itself.

Furthermore, if the tin plating layer on the inner surface of the wire barrel 11a is thick, the electric wire L and the tin plating layer adhere tightly, so that the contact resistance at the crimped portion is sufficiently low.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above example.
For example, the initial thickness of the tin plating layer 2 may be 0.5 μm or more and 2.0 μm or less. Of course, when the initial thickness of the tin plating layer 2 is other than 1.0 μm, the correlation shown in FIG. 5 is different, so the heat treatment time needs to be set accordingly.

Further, the form of the male terminal 10 and the female terminal 20 is not limited to the form shown in FIGS. 1 and 2, and the fitting type connection for obtaining electrical contact by fitting the male terminal and the female terminal. Any terminal is acceptable.

In the above embodiment, the copper base plating layer is formed on the copper or copper alloy base material, and the tin plating layer is formed thereon. However, the tin plating layer is formed directly on the base material. You may make it. Alternatively, after a nickel or silver base plating is performed instead of the copper base plating, a tin plating layer may be formed thereon. In these cases, a tin-nickel intermetallic compound or a tin-silver intermetallic compound is generated instead of the tin-copper intermetallic compound, and plays a role similar to that of the tin-copper intermetallic compound.

The laser to be used is not limited to the YAG laser, and other solid-state lasers or gas lasers may be used.

[0057]

As described above, according to the first aspect of the present invention, a plating step of forming a tin plating layer on the surface of a copper or copper alloy base material of at least one of a male component and a female component, The heat treatment by laser irradiation is performed only on the fitting portion in the fitting of the copper or copper alloy base material on which the plating layer is formed, and the vicinity of the interface with the copper or copper alloy base material of the tin plating layer in the fitting portion Laser irradiation step of alloying only the copper-tin alloy, a thin tin-plated layer can be left at the fitting portion, and the terminal can be maintained while maintaining a stable contact resistance. The insertion force can be reduced.

According to the second aspect of the present invention, the laser irradiation is performed on the surface of the copper or copper alloy base material on which the tin plating layer is formed, the surface being opposite to the sliding surface in the fitting.
It is possible to prevent the tin plating layer on the sliding surface from being melted and deformed to increase the contact resistance.

According to the third aspect of the present invention, one of the male part and the female part has a fitting portion of 0.1 μm to 0.1 μm.
Since the tin plating layer having a thickness of 3 μm is left and the tin plating layer having a thickness of 0.1 μm or more is left in the other fitting portion, the insertion force is reduced by at least 10% as compared with the conventional case. be able to.

[Brief description of the drawings]

FIG. 1 is a side view of a fitting connection terminal manufactured by a manufacturing method according to the present invention.

FIG. 2 is a partially cutaway plan view of a connection portion of the fitting type connection terminal of FIG. 1;

FIG. 3 is a plan view showing a plate-shaped strip of copper or copper alloy used for manufacturing the fitting connection terminal of FIG. 1;

FIG. 4 is a diagram illustrating a state in which laser irradiation is performed on the fitting connection terminal according to the present invention.

FIG. 5 is a diagram for explaining a change in a tin plating layer in a fitting portion due to laser irradiation.

FIG. 6 is a diagram showing a correlation between a residual tin plating layer thickness of a fitting portion of a male terminal and a terminal insertion force.

FIG. 7 is a diagram showing a correlation between the number of laser shots and the thickness of a residual tin plating layer.

FIG. 8 is a diagram illustrating a state of crimping of an electric wire and a wire barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Male terminal 11, 24 Crimp part 11a, 24a Wire barrel 12 Tab 20 Female terminal 21 Tongue piece 22 Emboss 23 Bead 25 Fitting part 31 Infrared lamp 32 Shielding plate 33 Cooling plate

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Atsuhiko Fujii 1-7-10 Kikuzumi, Minami-ku, Nagoya City, Aichi Prefecture Inside Harness Research Institute, Inc. (72) Inventor Yoshifumi Saka 1-Kikuzumi, Minami-ku, Nagoya City, Aichi Prefecture 7-10 Harness Research Institute, Inc. (72) Inventor Atsushi Nakamura 1-14 Nishisuehirocho, Yokkaichi-shi, Mie Sumitomo Wiring Systems, Ltd.

Claims (3)

[Claims] 1. A method of manufacturing a fitting connection terminal for obtaining electrical contact by fitting a male component and a female component, comprising: (a) copper or a copper alloy of at least one of the male component and the female component; A plating step of forming a tin plating layer on the surface of the base material, and (b) performing heat treatment by laser irradiation only on the fitting portion in the fitting in the copper or copper alloy base material on which the tin plating layer is formed. A laser irradiation step of alloying only the vicinity of the interface with the copper or copper alloy base material in the tin plating layer in the fitting portion into a copper-tin alloy. Manufacturing method. 2. The method for manufacturing a fitting connection terminal according to claim 1, wherein the heat treatment is performed on a sliding surface in the fitting of the copper or copper alloy base material on which the tin plating layer is formed. A method for manufacturing a fitting-type connection terminal, wherein the method is performed by irradiating a laser beam to an opposite surface. 3. The method for manufacturing a fitting type connection terminal according to claim 1, wherein the laser irradiation step is performed only on the fitting portion of one of the male part and the female part. .1 μm to 0.3 μ
a tin-plated layer having a thickness of 0.1 m or more and a tin-plated layer having a thickness of 0.1 μm or more only in the other fitting portion. .