KR20190037736A - Printed wire electrode and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electrode wire for electric discharge machining, having a coating layer formed on a core wire, and a manufacturing method thereof. The electrode wire for electric discharge machining comprises: a core wire; and a coating layer fixated so as to have a pattern on all or a part of the surface of the core wire, wherein the coating layer can be formed by performing a printing process using molten or powdered metal. The present invention alleviates a peeling or cracking problem of the coating layer and provides an electrode wire that is beneficial to the implementation of high processing speed and processing quality, thereby enabling all limiting factors in a process and a product, which are involved in the conventional plating process, to be effectively alleviated.

Description

TECHNICAL FIELD [0001] The present invention relates to a printed electrode wire and a method of manufacturing the same.

The present invention relates to an electrode wire for electric discharge machining and a manufacturing method thereof, and more particularly to an electrode wire for electric discharge machining in which a coating layer is formed on a core wire and a manufacturing method thereof.

Electric discharge machining (EDM) is a machining method for cutting or cutting a workpiece using a spark generated by a discharge between a running electrode wire and a workpiece. Generally, such an electrode wire for electric discharge machining is fabricated as a fine wire having a wire diameter of about 0.05 to 0.33 mm through a multi-stage drawing process for precision machining, and although it is made of a single material, A functional coating layer may be plated on the outside of the core wire in order to secure the surface of the core wire, followed by the multi-step drawing and the predetermined heat treatment.

However, when the coating layer is formed by plating, it is generally harmful to the environment, excessive facility investment is required, and it is difficult to continuously realize it in connection with other processes such as a drawing process, so that it is inferior in terms of cost and time, The material of the coating layer is limited.

In order to reduce the cost in terms of economy, it is advantageous that the diameter of the core wire to be plated is larger, but the number of subsequent drawing processes increases in proportion thereto and the plating layer is exposed to pressure and friction applied from the die in each drawing process. The possibility of becoming more. As a result, the plating layer is peeled off and separated, fine dust is generated, and the surface state and thickness of the plating layer are uneven as a whole, so that the quality of the electrode wire is deteriorated and the working environment is deteriorated in the electric discharge machining. Such peeling and dropping of the plating layer and generation of fine dust can be further exacerbated by the hard alloy layer formed in the entire plating layer.

In addition, in the case of an electrode wire for electric discharge machining in which a plating coating layer is formed, there is a problem that detergency by the coating layer is usually improved, accompanied by a problem of deterioration of electric conductivity. In order to alleviate this, there is an attempt to alloy the coating layer. There is a limit to satisfy both the conductivity and the cleaning property, and there is another problem that the alloyed coating layer acts as a hard phase in the subsequent drawing process as described above.

- Korean Patent Publication No. 10-2013-0027469 - Korean Patent No. 10-0632149

It is an object of the present invention to provide an electrode line which is advantageous in realizing excellent processing speed and machining quality by improving the peeling and cracking problem of the coating layer and having a high electric conductivity without inhibiting the cleaning property by the coating layer, And to provide a new electrode line manufacturing method that can replace the conventional plating process in the production of the formed electrode line.

DISCLOSURE OF THE INVENTION The present invention has been made as a result of intensive studies to solve the above-mentioned problems, and the gist of the present invention is as follows.

(1) A method for manufacturing an electrode wire for electric discharge machining, which is manufactured by forming a coating layer on the surface of a core wire and reducing the diameter of the coating wire, characterized in that the coating layer is formed so as to have a pattern with respect to all or a part of the core wire surface by a printing process Gt;

(2) The method for manufacturing an electrode wire for electric discharge machining as described in (1), wherein the printing process is performed by coagulating and pressurizing the molten metal.

(3) The method for manufacturing an electrode wire for electric discharge machining as described in (1), wherein the printing process is performed by a method of forcedly pressing the powder metal.

(4) The method for manufacturing an electrode wire for electric discharge machining according to (1), wherein the printing process further comprises a heat treatment after fixing the functional metal.

(5) The method for manufacturing an electrode wire for electric discharge machining as set forth in (1), further comprising a step of performing grooving on the core wire before forming the coating layer, wherein the grooving is performed so as to correspond to a pattern in which the coating layer is formed .

(6) The method for manufacturing an electrode wire for electric discharge machining according to (1), wherein the core wires are cleaned and preheated before the coating layer is formed.

(7) The method for manufacturing an electrode wire for electric discharge machining as set forth in (1), further comprising a step of reducing to a final diameter and then performing heat treatment.

(8) The method for manufacturing an electrode wire for electric discharge machining as described in (1), wherein the pattern is any of a point shape, a linear shape continuous in the longitudinal direction, or a spiral shape.

(9) core wire; And a covering layer fixed to have a pattern on all or a part of the surface of the core wire.

(10) The electrode wire for electric discharge machining according to (9), wherein the pattern is any one of a point shape, a linear shape continuous in the longitudinal direction, or a spiral shape.

(11) The electrode wire for electric discharge machining according to (9), wherein the coating layer is formed in a groove machined on the surface of the core wire.

(12) The electrode wire for electric discharge machining as described in (9), wherein the coating layer is formed by solidifying the molten metal or by forcedly pressing the powder metal.

(13) The electrode wire for electric discharge machining as described in (9) above, wherein the surface ratio of the coating layer is partly or entirely based on the outer surface of the electrode wire.

(14) The electrode wire for electric discharge machining according to (9), wherein the core wire is any one of copper, a copper alloy, iron, and an iron alloy.

(15) The electrode wire for electric discharge machining according to (9), wherein the coating layer is any one of zinc, aluminum, copper, copper alloy, and tin.

The method for manufacturing an electrode line according to the present invention can be applied to core wires and coating layers of various materials by replacing the conventional plating process by an environment-friendly process of printing a coating layer on a surface of a core wire in a predetermined pattern using molten or powdery metal, And cracks can be effectively suppressed, and the surface roughness and the surface layer ratio can be easily controlled according to the printing form. In addition, the manufacturing method is advantageous for miniaturization and continuous processing of the apparatus, and can reduce the processing cost and time.

In the electrode line according to the present invention, the surface ratio of the coating layer is easily controlled through the structure in which the coating layer is formed in all or part of the surface of the core wire in a predetermined pattern, thereby achieving excellent conductivity and cleaning property, have. In addition, the electrode line according to the present invention can maximize the processing speed and impart a high-precision surface roughness to the workpiece by changing the size of the functional metal particles when the coating layer is printed using the powder metal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram of a method for manufacturing an electrode wire for electric discharge machining according to the present invention; FIG.
2 is a schematic diagram of a printing process according to a first embodiment of the present invention.
3 is a pattern schematic diagram of an electrode wire for electric discharge machining according to an embodiment of the present invention.
4 is a schematic diagram of a printing process according to a second embodiment of the present invention;
5 is a perspective view of a molding die used in a printing process according to a third embodiment of the present invention;
6 is a cross-sectional structural view of the core wire and the electrode wire formed according to Fig.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or similar reference numerals are given to the same or similar parts. In addition, throughout the specification, when an element is referred to as including an element, it is understood that the element may include other elements, not the exclusion of any other element, unless specifically stated otherwise. Also, it is to be understood that when an element is referred to as being " selectively " provided, included, or included, it is not necessarily an essential component for solving the problem of the present invention, it means.

Fig. 1 shows a flowchart of a method for manufacturing an electrode wire for electric discharge machining according to the present invention. As shown in Fig. 3, the electrode wire 1 for electric discharge machining, which is an object of the present invention, has a structure in which a core wire 10 and a coating layer 20 of a predetermined pattern are formed thereon. Such an electrode line 1 is basically manufactured through the provision S1 of the core wire 10, the formation S2 of the coating layer 20, and the reduction S3 by drawing or the like. In this case, as described later, in step S2, the coating layer 20 may be formed by forming the coating layer 20 in a predetermined pattern. In order to firmly fix the core wire 10 and the coating layer 20, A heat treatment process can be selectively performed. The drawing process S3 may be performed in multiple stages as required. In addition, a heat treatment S4 for stabilizing mechanical properties such as tensile strength and elongation of the electrode line 1 can be selectively performed after the drawing process is completed with a final wire diameter of, for example, 0.05 to 0.33 mm (S3).

The present invention is characterized in that the coating layer 20 is formed in a predetermined pattern by a printing process in place of the conventional plating process in manufacturing the electrode wire 1 for electric discharge machining in which the coating layer 20 is provided on the surface of the core wire 10 And FIG. 2 shows a first embodiment of this printing process (S2). In the first embodiment, the printing process is performed in such a manner that the molten metal is solidified and forcedly pressed.

Referring to FIG. 2, first, a core wire 10 having a diameter of about 0.9 mm is provided through a plurality of drawing processes after press-extruding a molten / cast billet (not shown). For the core wire 10, a cleaning process for removing foreign matter remaining on the surface of the core wire 10 or a preheating process for the core wire 1 may be selectively performed before the coating layer 20 is formed. The washing may be carried out in a manner such as pickling, washing with water or high-pressure air blowing. The preheating process may be performed using a heating means such as, for example, a preheating coil 700 disposed around the core wire 10, and the preheating temperature is a temperature difference when the core wire 10 and the coating layer 20 are bonded through the printing process It is preferable to keep it near the melting point of the coating layer 20 so that the coating layer 20 can be minimized.

Next, a printing process using the coating layer 20 is performed. The printing process can be performed in such a manner that the molten metal is applied to the surface of the core wire 10 using the molten metal injection nozzle 100 and the coating layer 20 is fixed to the surface of the core wire 10 using the printing die 200 have. In this case, the fixing of the coating layer 20 by the printing die 200 includes a forced pressing process according to the reduction of the molten metal after solidification.

Specifically, the molten metal injection nozzle 100 comprises a tubular body 110, and a plurality of injection holes 120 are formed in the periphery of the tubular body 110 at predetermined intervals. The inlet end of each of the plurality of injection ports 120 is provided with a heating means such as a melting coil 130 for melting the functional metal provided on the powder or fillet. A through hole 112 through which the core wire 10 passes is formed in the inside of the tubular body 110 and a metal melted and supplied while passing through the inlet 120 simultaneously with the movement of the core wire 10 is inserted into the core wire 10, And is formed to have a predetermined thickness on the surface. The printing die 200 is provided at a rear end of the molten metal injection nozzle 100, and a cooling coil 230 is provided at a front end thereof. The coating layer 20 is solidified by heat exchange with the cooling coil 230 and then the surface of the core wire 10 is coated with the coating layer 20 after the core wire 10 coated with the coating layer 20 has been cooled down through the printing die 200. [ . In this case, the shape of the printing die 200 is preferably selected in consideration of the material characteristics of the core wire 1 and the coating layer 20, the printing linear velocity, the diameter before and after the forced pressure contact, and the like. Also, the printing dies 200 may be provided in one or a plurality of printing dies in spite of the embodiment. In the printing process, the reduction ratio of the cross-section for forced-pressure welding between the core wire 10 and the coating layer 20 may be, for example, 5 to 25%.

In this case, the thickness and line width of the coating layer 20 in the electrode line 1 after passing through the printing die 200 are set so that the inner diameter of the through hole 112 of the molten metal injection nozzle 100 and the outer diameter of the core wire 10 The diameter of the initial coating layer 20, the diameter of the initial coating layer 20 before and after passing through the plowing die 200, the hardness difference between the core wire 10 and the coating layer 20, and the like. The pattern of the coating layer 20 may be determined according to the arrangement of the injection port 120, the shape of the relative rotation between the core wire 10 and the printing die 200, and the supply period of the functional metal through the injection port 120. For example, when the core wire 10 moves without relative rotation with respect to the printing die 200, the core wire 10 has a continuous straight line in the longitudinal direction as shown in FIG. 3 (a) As shown in Fig. 3 (b), the spiral shape is continuous in the longitudinal direction. The relative rotation between the core wire 10 and the printing die 200 may be a method of rotating the printing die 200. When the supply of the molten metal through the injection port 120 is performed at regular intervals while the movement of the core wire 10 is made constant, a pattern of the coating layer 20 in the shape of a dot may be formed as shown in FIG. 3 (c) . The linear pattern is advantageous in that it can easily form a thick pattern and can be easily controlled in the use of a molding die 500 which will be described later. The spiral pattern is advantageous for precision machining, There is an advantage in cold working by applying the printing process. The pattern of the coating layer 20 is not limited to that shown in FIG. 3, but may be different from the arrangement of the injection port 120, the relative rotation between the core wire 10 and the printing die 200, The supply period of the metal, and the like, and can be implemented in various forms according to the manufacturing environment or the use.

Subsequently, the coating layer 20 is solidified and forcedly pressed onto the surface of the core wire 10, and then a heat treatment process is selectively performed, thereby completing the printing process. The heat treatment process can be performed by an electric heating means such as a heat treatment coil 600, for example. Since the heat treatment performed in the pre-drawing step is performed to increase the coupling force between the core wire 10 and the coating layer 20 by partially alloying through intermetallic diffusion only at the boundary between the core wire 10 and the coating layer 20, It is possible to minimize the occurrence of peeling, peeling, or fine dust generation of the coating layer due to the hard alloy layer formed in the entire plating layer. In this case, the heat treatment temperature and time can be determined in consideration of the material of the core wire 10 and the coating layer 20, and when diffusion and alloying are performed over the entire thickness of the coating layer 20 due to excessive heat treatment temperature or time, And microcracks are generated in step (S3), which is undesirable.

Subsequently, after the core wire 10 having been subjected to the printing process with respect to the coating layer 20 is completely drawn (S3 in Fig. 1), the electrode wire 1 drawn to a final diameter of approximately 0.05 to 0.33 mm is, for example, (Not shown) to selectively heat treat (S4 in FIG. 1) to stabilize the mechanical properties such as tensile strength and elongation of the electrode line 1. The coating layer 20 is forcedly press-fitted into the surface of the core wire 10 in the state where the drawing is completed with the final diameter and there is no step between the exposed coating layer 20 and the surface of the core wire 10.

FIG. 4 is a schematic view of a printing process according to a second embodiment of the present invention, in which a printing process for forming the coating layer 20 is performed in such a manner that a solid powder metal is forcedly pressed. On the other hand, in the second embodiment, the selective cleaning and preheating process for the core wire 10 in the previous stage of the printing process, the thickness and pattern type of the coating layer 20 applied through the printing process, The heat treatment process and the fresh and selective heat treatment process for the core wire 10 after completion of the printing process are the same as those of the first embodiment of FIG.

4, the printing process for the coating layer 20 is performed by supplying the solid powder metal to the surface of the core wire 10 by using the powder metal injection nozzle 300 while at the same time forcibly pressing the powder metal using the printing die 400 Can be performed in a fixed manner. In this case, since the powder metal supplied to the surface of the core wire 10 is already solid, when the coating layer 20 is fixed by the printing die 400, the coagulation process as in the embodiment of FIG. 2 is unnecessary, It includes only the forced pressure welding process.

Specifically, the powder metal injection nozzle 300 is formed of a tubular body 310, and a plurality of injection ports 320 are formed in the periphery of the body 310 with a predetermined interval. A through hole 312 through which the core wire 10 is passed is formed in the tubular body 310 and a powder metal is formed on the surface of the core wire 10 through the injection port 320 simultaneously with the movement of the core wire 10, . The printing die 400 is provided at a stage immediately after the powder metal injection nozzle 300 and the core wire 10 coated with the coating layer 20 having a predetermined thickness is passed through the printing die 400, And the surface is forcedly pressed. In this case, the powder metal injection nozzle 300 as a coating means for the coating layer 20 and the printing die 400 as a fixing means are integrally formed so that the solid powder metal is preliminarily fixed on the surface of the core wire 10 It is desirable to minimize disengagement.

The printing process according to the embodiment of FIGS. 2 and 4 may further include a step of machining the groove 12 with respect to the core wire 10 in the pre-stage of forming the coating layer 20. FIG. This groove 12 machining may be performed using the molding die 500 of FIG. 5, and the molding die 500 is subjected to a cleaning and preheating process as a pre-process for the core wire in the embodiments of FIGS. 2 and 4 It can be placed in the previous step process. 5 is a perspective view of a molding die 500 used for processing a groove 12 with respect to a core wire 10 according to an embodiment of the present invention. 10, and Fig. 6 (b) is a cross-sectional structure diagram of the electrode line 1 cut by drawing.

5 includes a tubular body 510 having a through hole 512 and a tooth 514 having a sawtooth shape is provided in the through hole 312. A core wire 10 slightly larger than the inner diameter of the through hole 512 passes through the molding die 500 and has a groove 12 having a linear shape continuous in the longitudinal direction as shown in Figure 6 (a) . Thereafter, when the molten metal of FIG. 2 is used or the powder metal of FIG. 4 is injected and supplied by using a nozzle, the coating layer 20 is stably received into the groove 12. 6 (b), when the cover layer 20 is accommodated in the groove 12, the core wire 10 is pulled out by using the printing dies 200 and 400 shown in Figs. 2 and 4, And the surface is firmly pressed against the surface. As a result, the pattern of the groove 12 corresponds to the formation pattern of the coating layer 20.

5, when the grooves 12 are formed on the core wire 10 in the previous stage of forming the coating layer 20, when the coating layer 20 is simply supplied to the surface of the core wire 10 according to FIGS. 2 and 4 It is possible to more precisely control the surface ratio of the coating layer 20 on the surface of the electrode line 1 by making it possible to form the coating layer 20 more firmly fixed by delimiting the boundary on the surface of the electrode line 1 It is advantageous.

In the embodiment of FIG. 5, if the molten metal of FIG. 2 is used, the solidification of the molten metal in the pre-reduction stage should be preceded and after the reduction by the printing dies 200 and 400 of FIGS. 2 and 4, ) Can be carried out. In this embodiment, the grooves 12 and the corresponding cover layer 20 patterns having a straight line shape continuing in the longitudinal direction in which the molding die 500 does not rotate are exemplified. However, the grooves 12 may be formed in various ways And the like. For example, when the molding die 500 is rotated while passing through the core wire 10, a continuous spiral groove 12 can be formed in the longitudinal direction, and a plurality of pins can be used around the core wire 10 The dot-shaped grooves 12 can be formed.

When the fixing of the coating layer 20 is performed in a boundary layer of two materials through a diffusion heat treatment after printing a molten metal or a powder metal in a predetermined pattern and forcing it to pressure contact as in the embodiment of the present invention instead of the conventional plating method, And so on.

First, since the boundary layer between the core wire and the coating layer is alloyed to increase the bonding force, peeling and cracking of the coating layer 20 can be effectively suppressed. Even if the core wire 10 or the coating layer 20 of various materials is selected, Can be equally expected by alloying through diffusion. In this case, the core wire 10 may be selected from copper, a copper alloy, iron or an iron alloy, and the coating layer 20 may be selected from zinc, aluminum, copper, copper alloy or tin.

Secondly, by controlling the surface ratio of the coating layer 20 with respect to the outer surface of the electrode line 1, the electric conductivity of the electrode line can be improved as the surface ratio of the core wire material having relatively excellent conductivity is increased. In this case, the surface ratio occupied by the coating layer 20 may be part or all.

Third, the surface ratio of the coating layer 20 is adjusted in consideration of the melting point and the vaporization temperature characteristics of the coating layer 20, thereby improving the processing performance. However, as the surface ratio of the coating layer 20 increases, the cleaning property of the coating layer 20 due to the fluxing effect of the coating layer 20 is improved during the electric discharge, so that the processing speed can be increased while the electric conductivity is lowered, . Therefore, the machining speed can be maximized by selecting the electrode line having the surface ratio of the appropriate coating layer 20 in consideration of the processing conditions such as the material of the workpiece, the thickness of the workpiece, the processing machine, the processing liquid, and the characteristics of the coating layer 20.

Fourth, when the printing process is performed using the powder metal as in the embodiment of FIG. 4, the particle size (particle size) of the blast metal can be selectively used. The surface ratio of the coating layer 20 can be adjusted by adjusting the particle size of the powder metal and the amount of the powder metal passing through the printing die 400. It is possible to maximize the processing speed by selecting the electrode line having the surface ratio of the appropriate coating layer 20 in consideration of the processing conditions and the characteristics of the coating layer 20. [

Fifth, the fritting process is eco-friendly compared to the conventional plating method, the electrode line manufacturing installation can be miniaturized as a whole, and the process can be easily implemented in a continuous process in conjunction with other unit processes, thereby reducing the process cost and time.

While the foregoing is directed to a specific embodiment of the present invention, it is to be understood that the above-described embodiment of the present invention has been disclosed for the purpose of illustration and is not to be construed as limiting the scope of the present invention, It should be understood that various changes and modifications may be made to the disclosed embodiments without departing from the spirit of the invention. It is therefore to be understood that all such modifications and alterations are intended to fall within the scope of the invention as disclosed in the following claims or their equivalents.

1: Electrode line
10: core wire 12: home
20:
100: molten metal injection nozzle
110: tubular body 112: through hole
120: inlet 130: molten coil
200: printing die
230: cooling coil
300: Powder metal injection nozzle
310: tubular body 312: through hole
320: inlet
400: Printing die
500: Molding die
510: tubular body
512: Through hole
514: Teeth
600: Heat treatment coil (part of the printing process)
700: preheating coil

Claims (15)

A method for manufacturing an electrode wire for electric discharge machining, which is manufactured by forming a coating layer on a surface of a core wire and reducing the coating layer, wherein the coating layer is formed so as to have a pattern with respect to all or a part of the core wire surface by a printing process.
The method according to claim 1, wherein the printing process is performed by coagulating and forcing the molten metal.
The method according to claim 1, wherein the printing process is performed by a method of forcedly pressing the powder metal.
The method according to claim 1, wherein the printing process further comprises a heat treatment after fixing the functional metal.
The method of manufacturing an electrode wire for electric discharge machining according to claim 1, further comprising: performing grooving on the core wire before forming the coating layer, wherein the groove machining is performed so as to correspond to a pattern in which the coating layer is formed.
The method for manufacturing an electrode wire for electric discharge machining according to claim 1, wherein the core wires are cleaned and preheated before forming the coating layer.
The method of manufacturing an electrode wire for electric discharge machining according to claim 1, further comprising a step of reducing to a final diameter and then performing a heat treatment.
The method for manufacturing an electrode wire for electric discharge machining according to claim 1, wherein the pattern is any one of a point shape, a linear shape continuous in the longitudinal direction, or a spiral shape.
Core wire; And a cover layer fixed so as to have a pattern on all or a part of the surface of the core wire.
10. The electrode wire for electric discharge machining according to claim 9, wherein the pattern is any one of a point shape, a linear shape continuous in the longitudinal direction, or a spiral shape.
The electrode wire for electric discharge machining according to claim 9, wherein the coating layer is formed in the groove machined on the surface of the core wire.
The electrode wire for electric discharge machining according to claim 9, wherein the coating layer is formed by solidifying the molten metal or by forcibly pressing the powder metal.
The electrode wire for electric discharge machining according to claim 9, wherein the surface ratio of the coating layer is partly or entirely based on an outer surface of the electrode wire.
The electrode wire for electric discharge machining according to claim 9, wherein the core wire is one of copper, a copper alloy, iron, and an iron alloy.
The electrode wire for electric discharge machining according to claim 9, wherein the coating layer is any one of zinc, aluminum, copper, copper alloy, and tin.

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