JPH03291328A - Production of formed part of metallic extra fine wire - Google Patents

Abstract

PURPOSE:To improve the straightness of an extra fine wire by annealing a wiredrawn extra fine metallic wire while applying tensile load and then carrying out forming. CONSTITUTION:A metallic wire rod is wiredrawn into an extra fine wire of the prescribed diameter. Annealing treatment is applied to this extra fine wire while applying tensile load, by which straightness in the stage of wire can be improved. Subsequently, the above extra fine wire is formed into the pre scribed shape, or further, the above extra fine wire is subjected to plating with Ni, etc., and then to stress relief annealing treatment to remove residual strain and uniformize yield strength. As a result, forming precision at the time of forming into the prescribed shape can be improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to pin probes (inspection probes) used in continuity testing devices for circuit patterns formed on, for example, liquid crystal substrates and semiconductor substrates; We are developing methods for manufacturing fine springs that elastically support pin probes, reinforcing wires for golf softballs, fishing lines, etc., and we are particularly concerned with the precision of forming metal wires when molding them into predetermined shapes. This invention relates to an improvement in a heat treatment process that can reduce surface distortion.

[Conventional technology]

In manufacturing an ultra-fine metal wire molded product such as the above-mentioned pin probe, which is made by forming an ultra-fine metal wire into a predetermined shape, first the metal wire is drawn into an ultra-fine wire of a predetermined diameter, which is then formed into a predetermined shape. It is common to perform heat treatment such as post-strain annealing. The wire drawing process employs a mechanical method of drawing the metal wire to a predetermined diameter by pulling the metal wire while compressing it with rollers.

By the way, in liquid crystal substrates used in liquid crystal projection devices, etc., the number of pixels is increasing in order to correspond to higher image quality, and in recent years, liquid crystal substrates with 300,000 pixels have been developed, It is thought that in the future, devices with 80 to 3 million pixels will be required. As the number of pixels increases, the pitch between circuit patterns on the liquid crystal substrate also becomes narrower. Therefore, in order to cope with such high density circuit patterns, it is necessary to make the pinch of each pin probe extremely small.

[Problem that the invention seeks to solve]

However, when using the above-mentioned conventional manufacturing method, there is a problem that the thinner the metal wire is, the more difficult it becomes to ensure the precision of forming it into a predetermined shape. Therefore, for example, when used in the above-mentioned pin probe, it tends to interfere with adjacent pin probes due to surface distortion of the molded product, and even if the wire diameter is reduced, the pitch cannot be narrowed.

The reason why it is difficult to cope with the above-mentioned high density and to improve the forming accuracy is considered to be because the straightness of the ultra-fine wire is not sufficient at the time of drawing into the ultra-fine wire.

The present invention has been made in view of the above-mentioned conventional problems.
The object of the present invention is to provide a method for manufacturing an ultra-fine metal wire molded product that can improve the straightness of the drawn ultra-fine metal wire and, as a result, greatly improve the forming accuracy.

[Means for Solving the Problems] The present invention comprises a first step of drawing a metal wire into an ultra-fine wire of a predetermined diameter, a second step of annealing the ultra-fine wire while applying a tensile load, and a second step of annealing the ultra-fine wire while applying a tensile load. A metal ultra-fine wire molded product having a third process of forming the ultra-fine wire that has passed through the second process into a predetermined shape or further plating it, and a fourth process of subjecting the ultra-fine wire of the predetermined shape to strain relief annealing treatment. This is a manufacturing method.

That is, the present invention is characterized in that an ultra-fine wire that has been drawn to a predetermined diameter is subjected to a so-called stretch relief process, in which the ultra-fine wire is annealed while applying a tensile load prior to being formed into a predetermined shape. focused on the importance of straightness of the strands in the pre-forming stage to improve forming accuracy, and in order to improve the straightness of the strands at this stage, it is necessary to apply tensile load after wire drawing. The present invention was completed by discovering that it is effective to perform the annealing treatment while adding the material.

Here, the ultra-thin wire (tension wire) in the present invention is approximately 120μ
This applies to wires with a wire diameter of 100 mm or less. Further, the annealing treatment performed while applying the above-mentioned tensile load is preferably performed under treatment conditions such that the strength after the heat treatment is approximately 10 to 20% lower than the strength at the end of the wire drawing process.

[Effect]

According to the method for manufacturing an ultra-fine metal wire molded product according to the present invention, the drawn ultra-fine wire is annealed while applying a tensile load, so that the straightness at this strand stage is improved and residual strain is removed. , the yield strength is made uniform, and as a result, the molding accuracy when molded into a predetermined shape is greatly improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

2rgJ to 4 are diagrams showing main parts of an inspection device using a pin probe manufactured by the method of the embodiment described later.

In the figure, reference numeral 1 denotes a pin probe, which consists of a mounting part 1a bent into a U-shape and a contact part 1b extending diagonally downward.
It has a self-elastic shape that absorbs dimensional errors when it comes into contact with the circuit pattern number 2 on the liquid crystal substrate 25. Further, the mounting portion 1a is fitted onto the edge of the base 6 of the inspection device, so that each of the bin probes 1 can be attached to the base 6.
are arranged and fixed at predetermined pitches. Note that the mounting pinch of each bottle probe 1 corresponds to the arrangement pitch of the circuit pattern.

In addition, each of the pin probes 1 has a Ni plating film 1lI3 formed as a base on the surface of an ultrafine wire 2 made of low carbon two-phase ma with a wire diameter of 120 μm or less, and a noble metal plating layer 4 is coated on the surface of the film 3. It was formed. Note that 7 is a lead wire that connects the end of the mounting portion 1a to a measuring device (not shown).

Here, the ultrafine wire 2 made of the low carbon dual-phase steel was previously proposed by the applicant of the present invention. This is FeFe-
A steel wire rod made of a C-5i-based iron-based alloy and having a composite metal structure in which a low-temperature transformation phase consisting of acicular martensite, bainite, or a mixture thereof is uniformly dispersed in a ferrite phase, e.g. C in %: 0.01~
0.50%, Si: 3° or less, Mn: 5.0% or less, balance Fe and inevitable impurities, wire diameter 3.0-6
．． 0 m wire rod was strongly worked to a wire diameter of 120 μm or less by primary heat treatment, secondary cold wire drawing, secondary heat treatment, and secondary cold wire drawing. This ultra-fine metal wA2 has a uniform fibrous fine metal structure in which a composite structure (two-phase structure) formed by combining the ferrite phase and the phase produced by low-temperature transformation extends in one direction, and has a processing cell size.

The fiber spacing is 5-100 and 50-1000, respectively, and the tensile strength is 300-600 kff/m"
It is.

Incidentally, such a manufacturing method is described in Japanese Patent Application Laid-Open No. 62-20824.

Next, a case in which the bottle probe 1 is manufactured by a method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

■, First, wire diameter 3.0~6°On having the above component composition.
A Ni plating film with a thickness of approximately 4 μm is formed on the surface of the steel wire rod, and this is subjected to the above-mentioned primary and secondary heat treatments.

Then, the wire is drawn into an ultra-fine wire having a wire diameter of 100 μm by secondary cold wire drawing (first step). Here, the above Ni
The plating film reduces friction between the wire rod and die during cold wire drawing, and provides self-lubricating properties that improve formability into a predetermined shape. Further, the Ni plating film is elongated to about 1 μm by the wire drawing process, and therefore, the elongated Ni plating film 3 has processing strain due to the wire drawing process.

(2) Then, the ultrafine wire with a wire diameter of 100 μm is annealed while applying a tensile load (second step).

Regarding the magnitude of this tensile load and the heat pattern, it is preferable to carry out the treatment under conditions that reduce the tensile strength of the ultra-fine cable wire by about 10 to 20% at the time the first step is completed. For example, as shown in Figure 6, the wire diameter is 100μ.
- In the case of -, the tension is 350F and the treatment temperature is 400 to 520C.

(2) Next, a noble metal plating coating layer 4 is formed so as to cover the Ni plating skin M3 of the ultrafine wire 2 which has been annealed.

Then, the plated ultra-fine wire 2 is connected to the U-shaped bent part 1.
It is bent and formed into a shape having a (third step).

(2) Finally, the bent ultrafine wire 2 is subjected to strain annealing at, for example, 360° C. for 1 hour (fourth step), thereby forming the bottle probe 1 having the shape shown in FIG. 3.

As described above, in this example, after the wire material was drawn into the ultra-fine metal wire 2, the ultra-fine wire 2 was annealed while applying a tensile load, so the straightness of the ultra-fine wire 2 was extremely high.

Therefore, the molding accuracy in the molding process in the next step is increased, and the surface distortion of the bottle probe 1 can be reduced. As a result, adjacent bin probes do not interfere with each other, the placement pinch can be reduced, and it is possible to cope with the above-mentioned high density circuit pattern.

In addition, in the above example, a Ni plating film is first formed on the wire and then this is drawn into an ultra-fine wire, which reduces friction between the wire and the die and improves formability into the bottle probe. Provides self-lubricating properties.

Furthermore, since the Ni plating film 3 has processing strain due to desirability processing, the adhesion of the noble metal plating coating layer 4 can be improved. The Ni plating film that has just been plated is porous with countless pinholes, so hydrogen generated during the plating process may be occluded within the Ni film, or air may remain in the porous film. Become. It is considered that this occluded hydrogen 7 residual air has an adverse effect on the adhesion of the noble metal plating.

In contrast, in this example, processing strain was applied to the Ni plating film by wire drawing, so the pinholes were crushed and disappeared, and the occluded hydrogen and residual air were released by the processing heat during wire drawing. As a result, a Ni plating film 3 containing almost no hydrogen or the like can be obtained. As a result, the adverse effects of hydrogen and the like can be avoided.

FIG. 5 is a diagram showing a modification of the bottle probe manufactured by the method of the present invention.

This bottle probe 10 has a structure in which its central portion is bent at an acute angle to form a beak-shaped contact portion 10b, and both ends 10a of this are inserted and fixed into a base 12.

In the case of this modification, as in the above embodiment, the surface distortion of the bottle probe 10 can be reduced, and the pinch in its arrangement can be narrowed.

Here, Table 1 shows experimental conditions and results for explaining the effect of improving straightness at the strand stage and reducing surface distortion after heat treatment of molded products by the method of the present invention.

In this experiment, the diameter was 100 pm? 100 1 m long pins of the same shape were each molded, stretch relief treatment was performed under various conditions, and the surface distortion (forming dimensional accuracy) after molding was measured. As is clear from the table, according to the method of the present invention,
It can be seen that the surface strain is extremely small.

In the above embodiment, a pin probe was explained as an example of a metal ultrafine wire molded product, but the method of the present invention can be applied to a method for manufacturing any metal ultrafine wire molded product, such as fine springs, reinforcing wires, fishing lines, etc. .

〔Effect of the invention〕

As described above, according to the method for manufacturing an ultra-fine metal wire molded product according to the present invention, the drawn ultra-fine metal wire is annealed while applying a tensile load, and then formed. This has the effect of improving the straightness of the ultra-fine metal wire at the strand stage, thereby reducing surface distortion of the molded product and improving molding accuracy.

No. table

[Brief explanation of the drawing]

FIG. 1 is a process diagram for explaining an embodiment of the method of the present invention.
2 to 4 are diagrams for explaining the pin probe manufactured by the method of the above embodiment, in which FIG. 2 is a perspective view showing the attached state of the pin probe, FIG. 3 is a cross-sectional side view thereof, FIG. 4 is a sectional view of the pin probe, FIG. 5 is a diagram showing a modified example of the pin probe, and FIG. 6 is a diagram showing stretch relief processing conditions. In the figure, 1.10 is a metal ultrafine wire molded product, and 2 is a metal ultrafine wire.

Claims (1)

[Claims] (1) The first step is to draw the metal wire into an ultra-fine wire with a predetermined diameter.
a second step of annealing the ultra-fine wire while applying a tensile load; and a third step of forming the ultra-fine wire after the second step into a predetermined shape or further plating it.
A method for manufacturing an ultra-fine metal wire molded product, comprising a fourth step of subjecting the ultra-fine wire of a predetermined shape to strain relief annealing treatment.