KR20190072841A - Manufacturing method of insert screw using cold forging process - Google Patents

Abstract

The present invention relates to a method for manufacturing an insert screw using a cold forging process, comprising: a step of inserting an alloy tool steel wire with a predetermined diameter into a trimming die, and forming a material to be processed of a predetermined length by means of a cutting process; a step of moving the material to be processed to a position of a lower die, such that a lower end of the material to be processed may be arranged on a mounting groove formed at the lower die; a step of pressurizing a first forging die having a processing groove formed to be recessed on the inside of one side end surface against the lower die such that the lower end of the material to be processed may be mounted on a bottom surface of the mounting groove, whereupon a portion of an upper end of the material to be processed protruding to the outside of the mounting groove is pressurized against an inner surface of the processing groove such that a shape thereof is deformed; and a step of pressurizing a second forging die, at which a Torx punch is fastened such that a distal end portion thereof may protrude, against the lower die, such that the upper end of the material to be processed may be pressurized by the Torx punch to form a fastening groove of a predetermined shape. Therefore, according to the present invention, a screw head portion is formed by means of two molding processes after a high-strength alloy tool steel wire of STD61 material is cut, such that an insert screw may be stably manufactured by means of a cold forging process without the wire being broken. Resultantly, the insert screw is imparted with high strength, and production costs are reduced and mass production is enabled by means of the cold forging process, thereby increasing productivity.

Description

Technical Field [0001] The present invention relates to a method of manufacturing an insert screw using a cold forging method,

The present invention relates to a method of manufacturing an insert screw using a cold forging method, and more particularly, to an insert screw manufacturing method capable of stably manufacturing an alloy tool steel material having a high strength such as a TD61 grade without cold- .

In general, insert cutting tools occupy about 30% of all cutting tools. They are the most widely used and standardized cutting tool types for high-quality, high-speed cutting. In order to overcome the inserts can be replaced in a form that is often used.

In the case of these inserts, many kinds of inserts are made of carbide (WC) and cermet grade, and the demand for machining of hard machining materials such as high strength steel, aluminum alloys and composites is gradually increasing. However, There is a problem of insert breakage and deviation due to load, increase of machining resistance, and insufficient fastening of the insert screw due to vibration during machining.

Due to the above problems, the insert screw requires high reliability in various fields such as high durability, high rigidity, high strength and abrasion resistance.

In order to ensure high reliability, such an insert screw can be manufactured from a high-stiffness alloy tool steel of STD61 grade. However, in order to manufacture an insert screw with these STD61 grades, a hot forging process, a sanding process and a separate CNC machining The manufacturing costs are increased due to the complicated processes, and the problem is that the labor / equipment and the working time are excessively consumed.

In addition, when the hot forging method is applied, the formability of the material is comparatively easy, but stress corrosion due to thermal fatigue / thermal stress, oxidation of the surface, low temperature strength of the material, stress generation during cooling, There is a high possibility of occurrence of cracks. In addition, the machining of the threads by CNC causes a lot of material waste due to cutting, and it involves problems such as excessive processing time, equipment and time, neck breakage, And the like, are somewhat limited.

In addition, the cold forging method which can reduce the production cost by requiring a fewer number of processing steps than the hot forging method and can be easily mass-produced by automation can be considered. However, the STD61 grade for producing an insert screw has high hardness, Since the toughness is low, the material is torn when a general cold forging method is applied.

Therefore, it is an object of the present invention to overcome the unreasonableness of the conventional manufacturing method of an insert screw and to provide an insert screw manufacturing method capable of reducing the production cost and enabling mass production by using the high strength alloy steel of STD61 grade to have high strength There has been a growing demand for

Korean Patent No. 1385930

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to stably manufacture an alloy tool steel material of high strength such as STD61 grades without tearing the material by cold forging.

According to an aspect of the present invention, there is provided a method of manufacturing a workpiece, comprising the steps of: inserting an alloy tool steel wire rod having a predetermined diameter into a cutting metal mold to form a workpiece having a predetermined length through a cutting operation; And a lower end portion of the working material is disposed on a seating groove formed in the lower mold. A first forging die having a machining groove recessed inward on one end surface thereof is pressed toward the lower mold side, Wherein a part of an upper end of the working material protruding outside the seating groove is seated on a bottom surface of the seating groove and is deformed by pressing on an inner side surface of the processing groove, The forging die is pressed toward the lower mold side so that the upper end of the working material is pressed by the toxic punch And a step of pressing to form a fastening groove of a specific shape.

The lower mold has a tapered inclined surface along the seating groove. When the first forging die is pressed toward the lower mold, the working material is pressed along the longitudinal direction to form a space between the inclined surface and the processing groove. And the uppermost portion of the working material is radially pushed by the tox punch so that the working material is pressed to the secondary surface by the inclined surface, .

In addition, the distal end portion of the tox punch is formed with a projecting portion having a six-projected radial shape, and a pressing surface to be pressed against the working material is formed by the outer edge of the projecting portion.

According to the present invention, since the high-strength alloy tool steel material of STD61 grade is cut, the head of the screw is formed through two die processes, so that the insert screw can be stably manufactured through cold forging without tearing of the material, The insert screw can be made to have a high strength and the production cost can be lowered through the cold forging and the mass production can be made, thereby increasing the productivity.

1 is a flowchart showing a method of manufacturing an insert screw using a cold forging method according to the present invention.
FIG. 2 is a simplified schematic drawing of an insert screw manufacturing process using a cold forging method according to the present invention.
3 is a detailed sectional view of a first forging process according to the present invention.
4 is a detailed sectional view of a second forging process according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flow chart showing a method of manufacturing an insert screw using a cold forging method according to the present invention, FIG. 2 is a simplified schematic drawing of an insert screw manufacturing method using a cold forging method according to the present invention, FIG. FIG. 4 is a detailed sectional view of a side view showing a second forging process according to the present invention. FIG.

Referring to the drawings, the present invention is a method of manufacturing an insert screw using an STD61 high-rigidity alloy tool steel as a raw material. The method includes a cutting step S110, a material feeding step S120, a first forging step S130 And a second forging process step S140.

In the material cutting processing step S110, an alloy tool steel wire rod having a predetermined diameter is inserted into the cutting die 10, and the cutting blade is continuously driven to reciprocate to form a workpiece A having a constant length. The length of the working material (A) is determined in advance in consideration of the shape of the mold for cold forming.

In the material transferring step S120, the workpiece A cut to a predetermined length by the cutting die 10 is clamped and moved onto the lower die 20. Here, the lower mold 20 is provided with a seating groove 21 on which the working material A is seated, and the working material A is arranged in a line on the seating recess 21. [

In addition, the depth of the seating groove 21 is formed smaller than the length of the cut workpiece A in consideration of forming a screw head on the upper portion of the workpiece A. That is, when the lower end of the working material A is seated on the bottom surface of the seating groove 21, a part of the upper end of the working material A is exposed to the outside of the seating groove 21.

A tapered inclined surface 22 is formed on the end surface of the lower mold 20 along the seating groove 21. The inclined surface 22 is formed such that the upper end of the screw head of the insert screw is formed as the inclined surface 22. [

The first forging step S130 is a step for pressing the first forging die 30 toward the lower mold 20 so that the upper end of the working material A is primarily deformed in a screw head shape, The first forging die 30 is formed with a machining groove 31 recessed inward at one end face so that when the first forging die 30 is pressed toward the lower die 20, A part of the upper end protruding outward from the seating groove 21 is pressed in the machining groove 31 to deform the end shape.

That is, as in the detailed cross-sectional structure of FIG. 3, the working material A inserted into the seating groove 21 while being compressed in the longitudinal direction of the working material A is not deformed, 20 and the machining grooves 31, the shape is deformed while being unfolded. As shown in the drawing, the sphere is radially expanded in a sphere shape while being compressed, and the sphere is deformed to have a larger diameter. At this time, the working material A does not need to be spread over the entire space between the inclined surface 22 and the machining groove 31, and some empty space can be formed.

After the upper surface of the working material A is deformed into a substantially screw head shape and then the first forging die 30 is returned to its original position and then the second forging die 40 is moved to the upper portion of the lower mold 20 .

The second forging process step S130 is a process for pressing the second forging die 40 toward the lower mold 20 to secondarily deform the upper end of the working material A so that the upper end thereof is fastened by the Tox punch 42 So as to complete the shape of the screw head.

The second forging die 40 is formed with a fastening hole 43 in which a torx punch is protruded. The torx punch 42 has a projecting portion 42a having six protruding star-shaped cross-sectional structures in a radial direction. The torx punch 42 has a pressing surface 41 Is formed.

4, the projecting portion 42a of the Tox punch 42 first presses the upper end of the working material A with the second forging die 40, The pressing surface 41 of the toxic punch 42 is brought into close contact with the lower mold 20 and the working material A is pushed radially so that the inclined surface 22 of the lower mold 20 And the pressing surface 41 of the Tokus punch 42, and is deformed secondarily.

By this secondary deformation, the working material A is pushed to the end of the inclined surface 22, and the original insert screw head shape is obtained without tearing of the material.

As described above, the shape of the insert screw can be formed through the cold forging without tearing the material even if only two die processes are performed after cutting the high strength alloy tool steel material of STD61 grade.

In addition, after the mold process, the head of the insert screw is machined, and the product is completed through rolling and heat treatment.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. Accordingly, the scope of the appended claims should include all such modifications and changes as fall within the scope of the present invention.

10: Cutting mold
20: lower mold 21: seat groove
22:
30: first forging die 31: machining groove
40: second forging die 41: pressing face
42: Tox Punch 43: Fastening Ball

Claims (3)

Inserting an alloy tool steel wire rod having a predetermined diameter into a cutting die and forming a workpiece having a predetermined length through a cutting operation;
Moving the working material to a lower mold position and placing a lower end of the working material on a seating groove formed in the lower mold;
Wherein a lower end of the working material is seated on a bottom surface of the seating groove and is protruded to the outside of the seating groove, A step of deforming a shape by pressing a part of an upper end of the upper part to the inner side of the processing groove;
A step of pressing a second forging die to which the toxic punch is fastened so as to protrude the distal end portion toward the lower mold so that the upper end of the working material is pressed by the toxic punch to form a fastening groove having a specific shape; Wherein the method comprises the steps of:
The method according to claim 1,
Wherein the lower mold has a tapered inclined surface along the seating groove so that when the first forging die is pressed toward the lower mold side, the working material is pressed along the longitudinal direction to form a space between the inclined surface and the processing groove The shape is deformed while being unfolded,
Wherein when the working material is pressed by the second forging die, the working material is secondarily spread on the inclined surface while the upper end of the working material is pushed radially by the pressing by the toxic punch. A method of manufacturing an insert screw.
3. The method of claim 2,
Wherein a tip portion of the tip portion of the toxic punch is formed radially with a protruding portion having a sectional structure and the pressing surface is pressed by the outer edge of the protruding portion to the working material.

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