JP2007223036A - Cu-w pipe and manufacturing method thereof, and electric discharging pipe electrode using the same and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Cu-W pipe having a very small outer diameter at 0.5 mm or less, a manufacturing method thereof, and an electric discharging pipe electrode using the same and a manufacturing method thereof. <P>SOLUTION: The Cu-W pipe is composed of Cu of 25-30 wt.%, Ni or Co of 0.1-0.5 wt.%, CeO<SB>2</SB>of 0-1.0 wt.% (not comprising zero), and W in residual parts except the unavoidable impurity, and formed of a pipe-like sintered body in which the minimum manufacturing dimension is formed by outer diameter of 0.08 mm×inner diameter of 0.04 mm, and grain diameter of the W in the sintered body is 0.5-3.0 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric discharge machining electrode and a method for manufacturing the electric discharge machining electrode. More specifically, the present invention relates to an electric discharge machining pipe electrode using an ultra-fine diameter Cu-W pipe used for an electric discharge machining electrode that can be used for lead frame production and the like. And its manufacturing method.

  In order to increase the memory capacity, integration of ICs has progressed, leading to a multi-pin lead frame and a fine pitch. Currently, in order to manufacture these lead frames, manufacturing by a press punching method and an etching method is performed. However, considering mass productivity and cost, the press punching method is currently advantageous. For this reason, IC lead frames manufactured by the press punching method are being miniaturized. A profile forming machine was normally used to process the die block of these press punching dies, but skill was required to unmanned the grinding process and improve assembly accuracy, which naturally led to a rise in manufacturing costs. Connected.

  Therefore, wire electric discharge machining technology has been introduced to solve these problems. However, in this wire electric discharge machining technique, in order to cut using a wire, a pilot hole through which the wire passes is necessary. In order to make this prepared hole, a Cu pipe has been mainly used as a conventional electrode for electric discharge machining.

  The wire electrical discharge machining technology used for the processing of semiconductor molds typified by IC lead frames can be finely processed depending on how the pilot hole that allows the wire to pass through can be used, in addition to the wire diameter. Is a key point to be determined. In other words, the shape of the prepared hole, straightness, the difference in diameter between the inlet and outlet, and the processing capability are decisive factors.

  Conventionally, a Cu pipe has been used for processing a pilot hole through which a wire passes, but there is a problem in processing accuracy. As for the pipe, it is possible to manufacture a pipe having an outer diameter of 80 μm at present, but there is a problem in terms of straightness. In other words, since the rigidity of Cu itself is low, there is a drawback that if a hole is made while discharging the cemented carbide, which is a workpiece, the Cu pipe is bent in the cemented carbide. In addition, if the thickness of the cemented carbide, which is the workpiece, is large due to the wear of the discharge of the Cu pipe, the hole will not penetrate unless it is changed several times, or the material cannot be drilled from a certain direction. Half of them had to be drilled from the opposite side, and there was a problem that remained uneasy about straightness.

  Patent Document 1 discloses an example of a Cu-W pipe. However, no specific manufacturing method is disclosed at all.

  In addition, Cu-W pipes have been manufactured conventionally, but the outer diameter D has a limit of 0.5 mm. The reason is mainly that the Cu-W pipe extrudes a material obtained by kneading a Cu powder and a W powder with a binder. Thereafter, the product is processed through a binder removal and sintering process.

  However, in this method, when the amount of the binder is large and an ultra-fine Cu-W pipe having an outer diameter of 0.5 mm or less is extruded, the shape cannot be maintained due to lack of strength at the time of debinding.

  On the other hand, Patent Document 2 discloses a method for producing a flowable tungsten / copper composite powder suitable for compression and sintering, but it is compression molding and not a powder for extrusion molding. In addition, the flowable tungsten / copper composite powder has a complicated manufacturing method, requires a lot of man-hours, and is not advantageous from the viewpoint of cost.

JP 2000-94219 A JP-A-8-311509

  Therefore, the technical problem of the present invention is to provide an ultra-fine Cu-W pipe having an outer diameter of 0.5 mm or less, a manufacturing method thereof, a pipe electrode for electric discharge machining using the same, and a manufacturing method thereof. is there.

  As described above, the point is how to accurately and stably process the pilot hole of the processing wire that follows the miniaturization of the semiconductor mold represented by the IC lead frame. In order to improve the shape, straightness, difference between the diameters of the inlet and outlet, and the processing ability, the problems remained in the Cu pipe. As a result, by adding a surfactant that improves the wettability between Cu powder, W powder and binder, the amount of the binder can be reduced, thereby finding that the strength capable of maintaining the shape can be maintained in debinding. It came to make invention.

According to the present invention, the composition is 25% by weight, Cu is 25-30%, Ni or Co is 0.1-0.5%, CeO ₂ is 0 (not including 0) -1.0%, and inevitable impurities A pipe-like sintered body whose balance excluding W is made of W, the minimum production dimension of the pipe is 0.08 mm outer diameter × 0.04 mm inner diameter, and the particle size of W of the sintered body is 0.00. A Cu—W pipe characterized by being 5 to 3.0 μm (not including 3.0) is obtained.

  Further, according to the present invention, in the Cu-W pipe, an electric discharge machining pipe electrode is obtained, wherein the Cu-W pipe is used as an electric discharge machining electrode.

Also, according to the present invention, there is provided a method for producing the Cu-W pipe, wherein the composition is wt%, Cu is 25-30%, Ni or Co is 0.1-0.5%, and CeO ₂ is 0. The first kneaded material is prepared by kneading the powder consisting of W (excluding 0) to 1.0% and the balance of W excluding inevitable impurities and the lipophilic binder or water-soluble binder. A nonionic surfactant is added to the kneaded product to prepare a second kneaded product, and the second kneaded product is extruded through a porthole die to produce a cylindrical material. A Cu-W pipe manufacturing method is obtained in which the Cu-W pipe is obtained by sintering.

  Moreover, according to this invention, the manufacturing method of the said Cu-W pipe WHEREIN: The average particle diameter of the said W powder is 0.5 micrometer-3 micrometers, The manufacturing method of the Cu-W pipe characterized by the above-mentioned is obtained.

  According to the present invention, in any one of the methods for producing a Cu-W pipe, the lipophilic binder is paraffin, and the water-soluble binder is selected from dextrin, gelatin, polyvinyl alcohol, methylcellulose, and polyethylene glycol. A Cu-W pipe manufacturing method is obtained.

  According to the present invention, in the method for producing a Cu-W pipe, the method for producing a Cu-W pipe is characterized in that the amount of the paraffin is 9% by weight with respect to the weight of the powder.

  According to the present invention, in any one of the methods for producing a Cu-W pipe, the amount of the nonionic surfactant is 2% by weight with respect to the weight of the powder when the HLB value is 10. A Cu-W pipe manufacturing method is obtained.

  In addition, according to the present invention, there is obtained a method of manufacturing a pipe electrode for electric discharge machining using any one of the above-described methods for manufacturing a Cu-W pipe.

Further, the detailed explanation of the present invention, in the Cu-W pipe, Cu is 25 to 30 wt%, Ni 0.1 to 0.5 wt%, CeO ₂ is 0-1.0 wt%, inevitable impurities And the balance of W in the alloy structure is 0.5 to 3.0 μm, and the relationship between the outer diameter D and the inner diameter d is 0.08 mm ≦ D ≦ 0.5 mm. It is preferable that 0.04 mm ≦ d ≦ 0.46 mm, Dd ≧ 0.04 mm, Young's modulus is 196 to 294 GPa, and the electric conductivity (% IACS) is 30 or more. It is done.

  By using this electrode, it becomes possible to provide an electrode with higher accuracy and efficiency than the conventional Cu pipe, and it becomes possible to open a very small diameter hole that could not be made with the conventional Cu-W pipe. It was.

  Here, the reason why the electric discharge machining electrode of the present invention is limited as described above will be described.

  First, in the present invention, the reason why the outer diameter, the inner diameter, and the difference between the outer diameter and the inner diameter are limited as described above is that the outer diameter of 0.08 mm is Cu-W having an outer diameter smaller than that in the current technology. Pipes cannot be manufactured. Also, the inner diameter of 0.04 mm is the same reason. Next, when the outer diameter is 0.5 mm or more, Cu pipes can be used sufficiently even if Cu-W is not used to make a fine hole. Also, the inner diameter of 0.46 mm is the same reason. The difference between the outer diameter and the inner diameter is 0.04 mm, that is, if there is no 0.02 mm on one side, the machining fluid may leak when the electrode is consumed while discharging. Moreover, it is because the one where there is a difference between the outer diameter and the inner diameter can flow a larger amount of machining fluid, and the sludge can be discharged well.

  In the present invention, the Young's modulus is limited as described above for the following reason.

  A characteristic of the Cu-W pipe is that it has a higher Young's modulus than the Cu pipe. Here, if the Young's modulus is less than 196 to 294 GPa, the superiority of the rigidity of the Cu-W pipe is lost, and the straightness of the hole opened by electric discharge machining is lost. On the other hand, when it becomes 294 GPa or more, the ratio of W increases and the electrical discharge machining characteristics deteriorate, so the Young's modulus is limited to 196 to 294 Pa.

  In the present invention, the electrical conductivity (% IACS) is set to 30 or more when the working fluid is water-soluble, the electrical conductivity of the electrode itself is too low to discharge when the processing liquid is 30 or less. It is heated and softened or melted. On the other hand, when the machining fluid is oily, electric discharge is caused by increasing the voltage, but the discharge energy increases in proportion thereto, and as a result, the electric discharge machining surface becomes rough and machining accuracy cannot be obtained.

  In the present invention, the composition is limited as described above for the following reason.

  As the characteristics of the Cu-W pipe, it is desirable that the electric conductivity is high and the rigidity is high. However, the ratio of Cu must be increased for the former, and conversely, the ratio of Cu must be decreased and the ratio of W must be increased for the latter. Therefore, Cu is limited to 25 to 30% by weight as a composition for satisfying these characteristics, and the balance excluding additives and inevitable impurities is set to W. For Ni and Co, Cu-W alloys are generally manufactured by powder metallurgy, but if the amount is less than 0.1% by weight, voids remain in the alloy even when sintered at a temperature higher than the melting point of Cu, and it is quite easy The density of the glass does not increase and the strength cannot be obtained. On the other hand, when the content is 0.5% by weight or more, the electrical conductivity of the Cu—W alloy is significantly reduced. Therefore, the ratio was limited to 0.1 to 0.5% by weight.

On the other hand, CeO ₂ contributes to the stability improvement of the discharge characteristics of the Cu—W alloy, which has inferior discharge characteristics as compared with Cu, but the addition of 1.0% by weight or more remarkably improves the sintering characteristics of Cu—W. It obstructs and eventually degrades the discharge characteristics. Therefore, the range is limited to 0 or more, preferably 0.2% by weight or more and 1.0% by weight or less.

  In the present invention, the grain size of W in the alloy structure is limited as described above for the following reason.

  Cu-W alloys are generally performed by powder metallurgy. The sintering proceeds when Cu melted between the W particles is drawn by capillary action, covers the surface of the W particles, and fills the voids between the W particles. When the particle size of W particles exceeds 3.0 μm, the surface area per unit mass becomes small, and excess Cu oozes out on the alloy surface. That is, when the shape of the alloy is a pipe, the pipe hole is blocked by the oozing Cu. On the other hand, when the particle size of W particles is less than 0.5 μm, the surface area per unit mass becomes large and the surface area of W particles cannot be sufficiently wetted, resulting in voids remaining, resulting in alloy strength. Absent. Therefore, the particle size of W in the alloy structure is limited to 0.5 to 3.0 μm.

  According to the present invention, in the method for manufacturing the ultra-fine diameter Cu-W pipe, the amount of the paraffin is 9% by weight with respect to the powder weight. can get.

  Moreover, according to the present invention, in the method for manufacturing any one of the ultra-fine Cu-W pipes, a nonionic surfactant is further included, and the amount of the nonionic surfactant is such that the HLB value is 10 In this case, an ultrafine Cu-W pipe manufacturing method is obtained, which is 2% by weight with respect to the powder weight.

  Moreover, according to this invention, the manufacturing method of the electrical discharge machining electrode characterized by using the manufacturing method of the ultra-fine diameter Cu-W pipe as described in any one of the above is obtained.

  Here, the surfactant used in the present invention is a nonionic surfactant, and a cationic or anionic surfactant is not preferable because it causes defects such as Pore in the Cu-W pipe.

  Nonionic surfactants are classified by the HLB value, which is an index of lipophilic hydrophilicity, and can be selected depending on the type of binder used. In other words, for example, when paraffin is used as the lipophilic binder, a low HLB value (6 or less) is selected, and when a water-soluble binder is used, a high HLB value (6 or more) is selected. To do.

  As the water-soluble binder, dextrin, gelatin, polyvinyl alcohol, methylcellulose, polyethylene glycol and the like can be selected.

  Here, as an example, the binder (paraffin), which was conventionally required up to 13% by weight, can be reduced to 4% by weight by adding a nonionic surfactant.

  Furthermore, in the manufacturing method of the present invention, the sliding resistance between the inner surface of the die and the material can be reduced by setting the die angle θ1 to 30 degrees so as to reduce the resistance at the time of extrusion. Cu-W pipes with a diameter of 0.5 mm or less can be extruded.

  As described above, the following electric discharge machining electrode can be manufactured by the technique described above.

  According to the present invention, it is possible to provide an ultra-fine Cu-W pipe having an outer diameter of 0.5 mm or less, a manufacturing method thereof, a pipe electrode for electric discharge machining using the same, and a manufacturing method thereof.

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

  FIG. 1 is a sectional view showing a die of an extrusion molding machine used for manufacturing an ultrafine Cu—W pipe according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a first die of the die shown in FIG. FIGS. 3A and 3B are views showing a second mold of the die shown in FIG. 1, wherein FIG. 3A is a plan view and FIG. 3B is a cross-sectional view.

  Referring to FIG. 1, in the figure, a die 1 includes a first mold 10 having a central axis in the vertical direction and a second mold mounted from one end of the first mold 10 in the central axis direction. 20.

  As shown in FIG. 2, the first mold 10 is provided with a hole 2 through which material passes along the central axis direction. The hole 2 is connected to a large-diameter portion 3 having a cylindrical inner surface having a relatively large diameter at one end, and a small-diameter portion 4 being a hole having a relatively small diameter at the other end, and these ends. And a conical portion 5 having a conical inner surface. The opening edge surfaces at both ends of the hole are chamfered. The dice angle θ1 of this conical surface is drawn to be slightly exaggerated in the drawing, but is approximately 30 degrees.

  As shown in FIGS. 3A and 3B, the second mold 20 includes a flange portion 11 provided at one end, followed by a cylindrical outer surface having a smaller outer diameter than the flange portion 11. A base 13, a cylindrical rod 14 projecting axially from the other end side from the center of the base, and a conical outer surface having a taper angle θ2 of approximately 30 degrees provided so that the diameter gradually decreases from the tip of the cylindrical rod 14. A conical portion 15 and a core wire portion 16 provided at the tip of the conical portion 15. The through holes 12 penetrating the flange portion 11 and the base portion along the central axis direction are provided concentrically at equal angular intervals so as to have openings around the cylindrical rod 14.

  When the second mold 20 is inserted in the direction of the central axis from the core wire 16 side toward the small diameter part on the large diameter part 3 side of one end of the first mold 10 shown in FIG. 2, as shown in FIG. In addition, the core wire 16 is inserted into the small diameter portion 4, the conical surfaces of the second mold 20 and the first mold 10 are parallel to each other, and the other surface of the flange portion 11 is the first surface. The die 1 is completed by being in contact with and fixed to one end surface of the mold.

  Here, referring again to FIG. 1, the material kneaded by an extrusion molding machine or the like is pushed into the through-hole 12, and the cylindrical rod and conical part of the second mold 20 and the conical part of the first mold. The space 6 is formed into a pipe shape, and is further extruded from the distal end portion 7 by the core wire 16 into a pipe shape. The cylindrical material extruded using this die becomes an ultrafine pipe by sintering without being deformed.

  Next, a specific manufacturing example of the Cu—W pipe according to the embodiment of the present invention will be described. In the following description, unless otherwise specified, “%” indicating a chemical component (composition) indicates “% by weight”.

Cu powder, W powder, Ni, Co powder, CeO ₂ powder and paraffin blended in predetermined amounts shown in Table 1 below were charged into a kneader at 9% based on the weight of the charged powder and kneaded. Next, 2% of a nonionic surfactant (HLB value 10) is added relative to the weight of the charged powder. In this process, kneading was performed for 1 hour, and then the kneaded material was taken out. Then, it is put into an extruder and extruded into the shape of a pipe using a porthole die (see FIG. 1). Next, the extruded Cu—W pipe was sintered at 1200 ° C. for 1 hour. Thereafter, the outer periphery was ground to obtain a Cu—W pipe having an outer diameter, an inner diameter, a Young's modulus, and% IACS as shown in Table 2.

  Table 3 below shows the characteristics of the Cu pipe used for comparison.

  Next, by using the Cu-W electric discharge machining electrode shown in Table 2 and the Cu pipe electric discharge machining electrode shown in Table 3 above, by drilling holes in the cemented carbide (G5) of various plate thicknesses, Were examined for wear, processing speed, and misalignment of the inlet and outlet.

  First, electrode consumption will be described. Using the same diameter Cu-W, Cu EDM electrode, measure the reduction of the electrode when the same number of holes are drilled, and use the reduction degree when the reduction of the Cu-W electrode is 100 as an index. It is shown in Table 4. The processing conditions are cemented carbide G5, plate thickness (t) = 5, 10, 15 mm.

  Next, the processing time will be described. Using Cu-W and Cu electric discharge machining electrodes of the same diameter, the time when the same number of holes were drilled was measured, and the time required for the Cu electrode when the time required for machining Cu-W was taken as 100 was calculated. The index is shown in Table 5 below. The processing conditions are cemented carbide G5, plate thickness (t) = 5, 10, 15 mm.

  Next, misalignment of the inlet / outlet will be described. Measure the misalignment of the inlet and outlet when the same number of holes are drilled using the same diameter Cu-W, Cu EDM electrode, and the misalignment of the inlet and outlet when the Cu-W EDM electrode is used is 100. Table 6 below shows, as an index, the misalignment at the inlet and outlet when the Cu electric discharge machining electrode was used. The processing conditions are cemented carbide G5, plate thickness (t) = 5.10, 15 mm.

  In the above description, the Cu-W pipe according to the present invention is applied to a pipe electrode for electric discharge machining used for welding or the like.

It is sectional drawing which shows the die | dye of the extrusion molding machine used for manufacturing the ultrafine Cu-W pipe by embodiment of this invention. It is sectional drawing which shows the 1st metal mold | die of the die | dye of FIG. It is a figure which shows the 2nd metal mold | die of the dice | dies of FIG. 1, (a) is a top view, (b) is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Die 2 Hole part 3 Large diameter part 4 Small diameter part 5 Conical part 6 Space 7 Tip part 10 1st metal mold | die 11 Flange part 12 Through-hole 13 Base 14 Column rod 15 Conical part 16 Core wire part 20 2nd metal mold | die

Claims (8)

Composition is 25% by weight, Cu is 25-30%, Ni or Co is 0.1-0.5%, CeO ₂ is 0 (not including 0) to 1.0%, and the balance excluding inevitable impurities is W A pipe-shaped sintered body having a minimum production dimension of 0.08 mm outer diameter × 0.04 mm inner diameter, and a particle size of W of the sintered body of 0.5 to 3.0 μm. Cu-W pipe characterized by being.   The Cu-W pipe according to claim 1, wherein the Cu-W pipe is used as an electric discharge machining electrode. The method for producing a Cu-W pipe according to claim 1, wherein the composition is 25% by weight, Cu is 25-30%, Ni or Co is 0.1-0.5%, and CeO ₂ is 0 (0). 1st kneaded product is prepared by kneading a powder composed of 1.0 to 1.0% and the balance excluding unavoidable impurities and W, and a lipophilic binder or a water-soluble binder. A non-ionic surfactant is added to produce a second kneaded product, and the second kneaded product is extruded through a porthole die to produce a cylindrical material, and the cylindrical material is sintered And obtaining the Cu-W pipe.   The method for producing a Cu-W pipe according to claim 3, wherein an average particle diameter of the W powder is 0.5 µm to 3 µm.   The method for producing a Cu-W pipe according to claim 3 or 4, wherein the lipophilic binder is paraffin, and the water-soluble binder is selected from dextrin, gelatin, polyvinyl alcohol, methylcellulose, and polyethylene glycol. Manufacturing method of Cu-W pipe.   5. The method for producing a Cu-W pipe according to claim 4, wherein the amount of the paraffin is 9% by weight with respect to the weight of the powder.   The method of manufacturing a Cu-W pipe according to any one of claims 3 to 6, wherein the amount of the nonionic surfactant is 2% by weight with respect to the weight of the powder when the HLB value is 10. A method for producing a Cu-W pipe, which is characterized in that it exists.   A method for producing a pipe electrode for electric discharge machining, wherein the method for producing a Cu-W pipe according to any one of claims 3 to 7 is used.

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