Precise nozzle and manufacturing method thereof

Abstract

The present invention efficiently manufactures a precision nozzle from a superhard alloy. The precision nozzle according to the present invention is manufactured by: a powder compression molding step in which a raw material powder is compression-molded using a transfer mold for forming a through-hole to obtain a molded body having an opening corresponding to an injection port and having a non-through hole; a sintering step in which the molded body is sintered to obtain a sintered body having an opening corresponding to the injection port and having a non-through cavity; an electrical discharge machining step for performing electrical discharge machining on the hole portion of the sintered body using an electrode; and a polishing step of polishing the sintered body subjected to electrical discharge machining from the opposite side of the opening part serving as the injection port to form an opening in the ejection port. The obtained precision nozzle (1) is formed of a superhard alloy and has a through-hole (3) penetrating from an injection port (2) to a discharge port (4), and the through-hole (3) includes at least a tapered hole section (3b) extending from the discharge port (4) in a direction in which the inner diameter increases toward the injection port (2).

Description

Technical Field

[0001] The present invention relates to a precision nozzle with a small aperture for the field of electronic components and the like, and a manufacturing method thereof. Background Art

[0002] With the miniaturization of electronic devices due to technological innovations in recent years, in the field of electronic components installed in smartphones, tablet personal computers (PCs), game consoles, motherboards, digital cameras, etc., in semiconductor devices, miniaturization and high density of semiconductor elements and integrated circuits are underway. In the manufacturing process of such semiconductor devices, as nozzles used for assembling minute parts or mounting on a substrate, reflow nozzles, suction nozzles, solder jetting nozzles, etc. are known, and any of these nozzles is a precision nozzle having minute ejection holes or suction holes. For example, as a reflow nozzle, a nozzle that supplies molten solder (solder paste) to a substrate by irradiating a solder ball with a diameter of about 40 μm with a laser to melt it is also used. Therefore, in such a reflow nozzle, in order to temporarily hold the solder ball at the ejection port, the aperture of the ejection port must be adjusted to a minute aperture comparable to the diameter of the solder ball. In addition, since precision nozzles such as reflow nozzles must be correctly positioned, high precision is also required for the flow path shape. Therefore, precision nozzles such as reflow nozzles must be highly precision machined. In particular, reflow nozzles are also required to have durability, so they are made of cemented carbide, but since cemented carbide is hard and difficult to machine, the machining efficiency of precision machining is low. Therefore, it is difficult to efficiently manufacture precision nozzles such as reflow nozzles using well-known techniques.

[0003] In Japanese Patent Laid-Open No. 2022-85914 (Patent Document 1), a nozzle for bonding electronic components that ejects an adhesive required for mounting electronic components is disclosed, which is formed of cemented carbide and includes a front end portion forming an ejection through-hole having an ejection port with a diameter of 50 μm or less, and a main body portion having an internal space for supplying the adhesive to the front end portion.

[0004] In Japanese Patent Laid-Open No. 2022-89371 (Patent Document 2), a nozzle for bonding electronic components that ejects an adhesive required for mounting electronic components is disclosed, which is formed of cemented carbide and includes an ejection through-hole having an ejection port with a diameter of 50 μm or less, and a main body portion having an internal space for supplying the adhesive to the ejection through-hole.

[0005] In Patent Documents 1 and 2, a nozzle has been described. The diameter of the ejection port of the through-hole for ejection of this nozzle is smaller than the diameter of the injection port, so that the adhesive can be easily ejected in a fine amount and ejection diameter. In the drawings, a nozzle having a two-stage flow path shape has been disclosed. The two-stage flow path shape is: a flow path in which the inner diameter gradually decreases from the injection port in the downstream direction, and a flow path having the same inner diameter (linear flow path) from this flow path to the ejection port. In addition, in Patent Documents 1 and 2, regarding the diameter of the ejection port, from the viewpoint of being able to eject an adhesive suitable for high-density mounting, the diameter of the ejection port is preferably 30 μm or less.

[0006] In addition, in Patent Documents 1 and 2, since high precision is required for the inner diameter and ejection axis of the through-hole for ejection, as a method for forming the through-hole for ejection, a method of forming by perforating at a predetermined position, a method of forming by lamination, and a method of forming by die processing can be used.

[0007] In addition, in Patent Documents 1 and 2, as a method for forming the through-hole for ejection with high precision when forming the main body part and the front end part from a sintered body of metal powder, a method of providing the through-hole for ejection when forming the sintered body, and a method of forming the through-hole for ejection by perforation or the like after forming the sintered body have been described.

[0008] On the other hand, in Japanese Unexamined Patent Application Publication No. 2022-22419 (Patent Document 3), an electric discharge machining method has been disclosed. This method uses a discharge electrode having a diameter larger than the diameter of the hole to be perforated. With the discharge electrode as the positive electrode and the workpiece as the negative electrode, the discharge electrode having a diameter larger than the diameter of the hole to be perforated is rotationally fed at a feed rate of 30 to 200 μm / s, and a hole is formed in the workpiece while consuming the discharge electrode.

[0009] [Prior Art Documents]

[0010] [Patent Documents]

[0011] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-85914

[0012] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2022-89371

[0013] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2022-22419. Summary of the Invention

[0014] [Problems to be Solved by the Invention]

[0015] However, in the manufacturing methods of the nozzles described in Patent Document 1 and Patent Document 2, it is difficult to efficiently manufacture precision nozzles from cemented carbide. In particular, for precision nozzles made of cemented carbide with an orifice diameter of less than 45 μm (especially less than 30 μm), although the manufacturing itself is extremely difficult, Patent Documents 1 and 2 do not describe a specific manufacturing method, nor do they describe the orifice diameter of the actually manufactured nozzles.

[0016] In addition, in the nozzle of Patent Document 2, in order to eject the adhesive, the flow path connected to the orifice is formed in a straight line, but depending on the application, a tapered shape may also be required. For example, in a reflow nozzle using solder balls, in order to smoothly eject the solder paste, it is also required to form the flow path connected to the orifice in a tapered shape.

[0017] Furthermore, in Patent Document 2, it is described that it is easy to form a micro-diameter ejection through-hole by mechanical machining for perforation. As a general machining method for opening holes, drilling is commonly used. However, in the machining of cemented carbide, due to the high hardness of the material, it is difficult to machine with general tools, so electrical discharge machining is mostly selected. As a relatively new machining method, it is possible to machine micro-holes with a special tool dedicated to high-hardness materials such as cemented carbide and a special processing machine that can rotate the tool at high speed. However, when machining micro-holes with a diameter of about 40 μm using this method, in order to maintain the cutting edge strength of the drill bit used, the length of the cutting edge must be shortened. This is because if the cutting edge length of a drill bit with a micro-diameter cutting edge increases, the cutting edge of the drill bit will break during manufacturing or use. As a drill bit that can perform the above-mentioned special micro-machining on cemented carbide among the commercially available drill bits, an ultra-small diameter drill bit for fine ceramics ("UVM-CERA (special product)" manufactured by OSG Co., Ltd.) can be cited. However, in such an ultra-small diameter drill bit, the length of the drill bit cutting edge is selected according to the diameter of the drill bit cutting edge. When the diameter of the drill bit cutting edge is 40 μm, the length of the drill bit cutting edge is 0.4 mm. This is because a slender shape with a micro-diameter of about 40 μm and a length exceeding 0.4 mm cannot maintain the strength as a drill bit cutting edge. Therefore, the mechanical machining described in Patent Document 2 cannot form a micro-through-hole with a diameter of about 40 μm in cemented carbide with a thickness exceeding 0.5 mm.

[0018] In addition, in the electrical discharge machining method of Patent Document 3, the control of the discharge electrode is complex, the productivity is low, and the shape of the electrode changes during the manufacturing process. Therefore, it is not suitable for the manufacturing of precision nozzles. Furthermore, even if this method is used, it is impossible to manufacture precision nozzles with an orifice diameter of less than 45 μm.

[0019] Therefore, an object of the present invention is to efficiently manufacture precision nozzles from cemented carbide.

[0020] Another object of the present invention is to provide a novel cemented carbide precision nozzle with high productivity, a nozzle diameter of less than 45 μm, and a non-thin-walled tapered hole portion, and a manufacturing method thereof.

[0021] [Means for Solving the Problems]

[0022] As a result of intensive studies by the inventors of the present invention to solve the above problems, it was found that in a method for manufacturing a cemented carbide precision nozzle including a tapered hole path extending from a nozzle outlet along an inner diameter increasing in the direction toward an injection port, the method includes the following steps: a powder compression molding step of using a transfer mold for forming the above through hole to compress and mold raw material powder to obtain a molded body having an opening corresponding to the above injection port and an unpenetrated hole portion; a sintering step of sintering the obtained molded body to obtain a sintered body having an opening corresponding to the above injection port and an unpenetrated hole portion; an electrical discharge machining step of inserting an electrode into the hole portion of the above sintered body for electrical discharge machining; and a grinding step of grinding the sintered body that has been subjected to electrical discharge machining from the side opposite to the opening that becomes the injection port to form an opening of the nozzle outlet. By passing through the above steps, the present invention is completed by efficiently manufacturing a precision nozzle with cemented carbide.

[0023] That is, as a method for manufacturing a precision nozzle according to Embodiment [1] of the present invention, the precision nozzle is formed of cemented carbide, has a through hole penetrating from an injection port to a nozzle outlet, and the above through hole at least includes a tapered hole portion extending from the above nozzle outlet along an inner diameter increasing in the direction toward the above injection port, and the method includes the following steps: a powder compression molding step of using a transfer mold for forming the above through hole to compress and mold raw material powder to obtain a molded body having an opening corresponding to the above injection port and an unpenetrated hole portion; a sintering step of sintering the above molded body to obtain a sintered body corresponding to the above molded body; an electrical discharge machining step of inserting an electrode into the hole portion of the above sintered body for electrical discharge machining; and a grinding step of grinding the sintered body that has been subjected to electrical discharge machining from the side opposite to the opening that becomes the injection port to form an opening of the nozzle outlet.

[0024] Embodiment [2] of the present invention is an embodiment in which, in the above Embodiment [1], the cross-sectional shape of the above through hole is circular, elliptical, or polygonal.

[0025] Embodiment [3] of the present invention is an embodiment in which, in the above Embodiment [2], the cross-sectional shape of the above through hole is circular.

[0026] Aspect [4] of the present invention is a form in which, in the powder compression molding step of any one of the foregoing aspects [1] to [3], the shape of the foregoing transfer mold corresponds to the shape of the foregoing through-hole, and the shape of the tapered portion corresponding to the foregoing tapered hole portion is a conical shape, an elliptical conical shape, or a polygonal conical shape.

[0027] Aspect [5] of the present invention is a form in which, in the foregoing aspect [4], the shape of the tapered portion corresponding to the foregoing tapered hole portion is a conical shape.

[0028] Aspect [6] of the present invention is a form in which, in the foregoing aspect [5], the front end diameter of the conical portion of the foregoing transfer mold corresponding to the foregoing tapered hole portion is 5 μm or less.

[0029] Aspect [7] of the present invention is a form in which, in the electrical discharge machining step of any one of the foregoing aspects [1] to [6], the shape of the foregoing electrode corresponds to the shape of the foregoing transfer mold.

[0030] Aspect [8] of the present invention is a form in which, in the foregoing aspect [7], the shape of the foregoing electrode corresponding to the foregoing tapered hole portion is a conical shape, and the front end diameter of the conical portion of the foregoing electrode corresponding to the foregoing tapered hole portion is 5 μm or less.

[0031] Aspect [9] of the present invention is a form in which, in the grinding step of any one of the foregoing aspects [1] to [8], based on the image obtained by photographing the grinding surface using a camera, it is confirmed whether there is a hole that becomes the ejection port and its diameter.

[0032] Aspect

[10] of the present invention is a form in which, in any one of the foregoing aspects [1] to [9], the foregoing through-hole is composed of the foregoing tapered hole portion and a cylindrical hole portion extending from the foregoing tapered hole portion to the foregoing injection port.

[0033] Aspect

[11] of the present invention is a form in which, in any one of the foregoing aspects [1] to

[10] , the diameter of the foregoing ejection port is less than 30 μm.

[0034] Aspect

[12] of the present invention is a form in which, in any one of the foregoing aspects [1] to

[11] , the foregoing precision nozzle is a nozzle for electronic parts.

[0035] Aspect

[13] of the present invention is a form in which, in any one of the foregoing aspects [1] to

[12] , the foregoing precision nozzle is a reflow nozzle for melting and ejecting solder balls.

[0036] In the present invention, as the form

[14] , it also includes a precision nozzle formed of cemented carbide and having a through-hole that penetrates from the injection port to the ejection port; the aforementioned through-hole includes a tapered hole portion that extends from the aforementioned ejection port along the inner diameter in a direction that increases toward the aforementioned injection port; the diameter of the aforementioned ejection port is less than 45 μm; and the length of the aforementioned tapered hole portion in the nozzle axis direction is 1 mm or more.

[0037] The form

[15] of the present invention is a form in the aforementioned form

[14] , in which the length of the aforementioned tapered hole portion in the nozzle axis direction is 10 times or more the diameter of the aforementioned ejection port.

[0038] The form

[16] of the present invention is a form in the aforementioned form

[14] or

[15] , in which the shape of the aforementioned ejection port is circular and the roundness of the aforementioned ejection port is 5 μm or less.

[0039] The form

[17] of the present invention is a form in any one of the aforementioned forms

[14] to

[16] , in which the outer shape of the precision nozzle of the aforementioned ejection port is an isotropic shape, the shape of the aforementioned ejection port is circular, and the concentricity of the aforementioned outer shape and the aforementioned ejection port is 10 μm or less.

[0040] The form

[18] of the present invention is a form in any one of the aforementioned forms

[14] to

[17] , in which the inclination angle of the aforementioned tapered hole portion is 3 to 60°.

[0041] The form

[19] of the present invention is a form in any one of the aforementioned forms

[14] to

[18] , in which the diameter of the aforementioned ejection port is less than 30 μm.

[0042] The form

[20] of the present invention is a form in any one of the aforementioned forms

[14] to

[19] , in which the diameter of the aforementioned ejection port is 1 μm or more and less than 30 μm; the length of the aforementioned tapered hole portion in the nozzle axis direction is 1 to 20 mm; the length of the aforementioned tapered hole portion in the nozzle axis direction is 100 times or more the diameter of the aforementioned ejection port; the shape of the aforementioned ejection port is circular and the roundness of the aforementioned ejection port is 5 μm or less; the outer shape of the precision nozzle of the aforementioned ejection port is circular and the concentricity of the aforementioned outer shape and the aforementioned ejection port is 10 μm or less; and the inclination angle of the aforementioned tapered hole portion is 4 to 50°.

[0043] The form

[21] of the present invention is a form in any one of the aforementioned forms

[14] to

[20] , in which the aforementioned cemented carbide is an alloy containing tungsten carbide.

[0044] [Advantages of the Invention]

[0045] In the present invention, there is a manufacturing method that combines a powder pressing step using a specific transfer mold, a sintering step, an engraving electrical discharge machining step using a specific electrode, and a grinding step for grinding a sintered body that has been electrically discharge machined into a specific shape. Accordingly, a precision nozzle can be efficiently manufactured from cemented carbide. In particular, it is possible to simply manufacture a novel precision nozzle made of cemented carbide that has a nozzle outlet diameter of less than 45 μm and a tapered hole portion with a non-thin wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic perspective view showing an example of the precision nozzle of the present invention.

[0047] Figure 2 For Figure 1 schematic sectional view taken along line I-I of.

[0048] Figure 3 It is a schematic sectional view showing another example of the precision nozzle of the present invention.

[0049] Figure 4 It is a schematic sectional view showing yet another example of the precision nozzle of the present invention.

[0050] Figure 5 It is a schematic sectional view showing other examples of the precision nozzle of the present invention.

[0051] Figure 6 For explaining Figure 4 the nozzle outlet diameter and the depth of the tapered hole portion of the precision nozzle of.

[0052] Figure 7 For explaining Figure 5 the nozzle outlet diameter and the depth of the tapered hole portion of the precision nozzle of.

[0053] Figure 8 It is a schematic process diagram for explaining the powder pressing step and the electrical discharge machining step in the manufacturing method of the precision nozzle of the present invention.

[0054] Figure 9 It is a schematic process diagram for explaining the sintering step and the electrical discharge machining step in the manufacturing method of the precision nozzle of the present invention.

[0055] Figure 10 It is a schematic process diagram for explaining the grinding step in the manufacturing method of the precision nozzle of the present invention.

[0056] Figure 11 It is a micrograph of the tip of the transfer mold (press pin) used in the examples.

[0057] Figure 12 It is a micrograph of the tip of the electrode used in the examples.

[0058] Figure 13 Microscopic photograph of the tip of the precision nozzle obtained just after the ejection opening of the through hole was formed in Example 1.

[0059] Figure 14 Microscopic photograph of the cross section of the tip of the precision nozzle obtained in Example 1.

[0060] Figure 15 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 2.

[0061] Figure 16 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 3.

[0062] Figure 17 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 4.

[0063] Figure 18 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 5.

[0064] Figure 19 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 6.

[0065] Figure 20 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 8.

[0066] Figure 21 Microscopic photograph of the tip of the precision nozzle in which the ejection opening of the through hole has been formed in Example 9. Detailed implementation mode

[0067] [Material of the precision nozzle]

[0068] The cemented carbide as the material of the precision nozzle of the present invention is not particularly limited. Representative cemented carbides include alloys containing metal carbides of Groups 4 to 6 of the periodic table, and among them, alloys containing tungsten carbide WC (tungsten carbide) (WC-based alloys) are widely used.

[0069] The WC-based alloy can be formed from WC as the main component and a binding component that forms a liquid phase and a binding phase by sintering.

[0070] As the binding components, for example, the metals of Groups 8 to 10 of the periodic table such as manganese Mn, iron Fe, cobalt Co, nickel Ni, etc. can be cited. These binding components can be used alone or in combination of two or more. Among these binding components, cobalt Co and / or nickel Ni are more preferably used, and cobalt Co is particularly preferably used.

[0071] With respect to 100 parts by mass of tungsten carbide, the ratio of the binding component (especially cobalt Co) can be 30 parts by mass or less, more preferably 0.5 to 25 parts by mass, and still more preferably 1 to 20 parts by mass.

[0072] The WC-based alloy may further contain metal carbides other than the aforementioned main components (other metal carbides). As other metal carbides, for example, titanium carbide TiC, niobium carbide NbC, tantalum carbide TaC, chromium carbide Cr 3 C 2 etc. can be cited. These other metal carbides can be used alone or in combination of two or more. Among these other metal carbides, TiC, TaC, Cr 3 C 2 .

[0073] The WC-based alloy may further contain elemental metals other than the aforementioned binding components (other elemental metals). As other elemental metals, for example, titanium Ti, zirconium Zr, vanadium V, niobium Nb, tantalum Ta, chromium Cr, molybdenum Mo, tungsten W, rhenium Re, etc. can be cited. These other elemental metals can be used alone or in combination of two or more. Among these other elemental metals, V and / or Cr are more preferably used.

[0074] With respect to the entire 100 parts by mass of the WC-based alloy, the proportion of other elemental metals can be 5 parts by mass or less, more preferably 0.1 to 3 parts by mass, and still more preferably 0.2 to 2 parts by mass.

[0075] The WC-based alloy may further contain a carbon source C (such as carbon black), and may contain unavoidably mixed components.

[0076] As the WC-based alloy, for example, WC-Co-based alloy, WC-TiC-Co-based alloy, WC-TaC-Co-based alloy, WC-TiC-TaC-Co-based alloy, WC-Ni-based alloy, WC-Ni-Cr-based alloy, etc. can be cited. Among them, the WC-Co-based alloy is widely used.

[0077] [Shape of the precision nozzle]

[0078] The shape of the precision nozzle of the present invention is not particularly limited as long as it has a through-hole that penetrates from the injection port to the ejection port, and the through-hole at least includes a tapered hole portion that extends in a direction where the inner diameter increases toward the injection port starting from the ejection port. The detailed shape of the nozzle of the present invention will be described below with reference to the drawings.

[0079] Figure 1 FIG. is a schematic perspective view of an example of the precision nozzle of the present invention, Figure 2 is a schematic cross-sectional view taken along line I-I of.

[0080] The precision nozzle 1 has a circular through-hole 3 with a circular cross-section that penetrates from a circular injection port 2 for injecting the ejected body to a circular ejection port 4 for ejecting the ejected body. The through-hole 3 serves as a passage (or flow path) for the ejected body such as gas, liquid, or solid to pass through. The through-hole 3 includes: a tapered hole portion 3b that extends in a direction where the inner diameter increases toward the injection port 2 starting from the ejection port 4, and a cylindrical hole portion 3a that extends from the upstream end of the tapered hole portion 3b to the injection port 2 with substantially the same inner diameter. In addition, the outer periphery corresponding to the tapered hole portion 3b is formed in a pointed shape toward the ejection port 4. Specifically, the inclination angle θ (the angle between the nozzle axis and the inclined wall) of the tapered hole portion 3b is 10° with respect to the nozzle axis.

[0081] In Figure 1 In the shown precision nozzle 1, the diameter φ of the ejection port 4 formed at the front end of the tapered hole portion 3b is about 20 μm. In well-known precision nozzles, the diameter φ of the ejection port is at least about 40 μm in thin-walled nozzles because it is difficult to achieve a manufacturing method for a precision nozzle with an ejection port diameter (or aperture) less than 30 μm in the well-known manufacturing method described in Patent Document 2. In addition, although the details of the well-known manufacturing method are not described in Patent Document 2, when high precision is required to form a fine ejection port, in the well-known technology, a method of forming a fine ejection port by electrical discharge machining of a sintered body having a cavity corresponding to the inside of the nozzle from the ejection port side toward the inside of the nozzle (from the opposite side of the injection port) is usually considered. This is because, although it is easy to form a shape corresponding to the shape of the electrode at the entrance of the machining due to the formation of a fine ejection port by electrical discharge machining, it becomes difficult to maintain a uniform shape as the machining progresses. Especially to form a fine ejection port, an electrode as thin as a hair and prone to bending needs to be used, so it is even more difficult to machine. Therefore, the through-hole machined by this well-known method becomes a through-hole having the shape shown in the drawings of Patent Document 2, that is, a through-hole having a cylindrical hole portion extending from the ejection port toward the injection port. In addition, if a thin and easily bendable fine electrode is used, it is also difficult to align its position with the injection port side, and it is difficult to manufacture a high-precision nozzle.

[0082] That is, in the method of finally processing from the nozzle outlet side to form a through hole, it is impossible to manufacture a precision nozzle having a tapered hole portion as shown in Figure 1 The precision nozzle having a tapered hole portion has a shape extending from the nozzle outlet along the inner diameter in a direction increasing toward the injection port. Therefore, in the precision nozzle obtained by a well-known method such as Patent Document 2, although a fine nozzle outlet with a diameter of about 40 μm of the nozzle outlet is formed, the shape of the hole portion extending from the nozzle outlet is not a shape extending from the nozzle outlet along the inner diameter in a direction increasing toward the injection port. In particular, in a precision nozzle having a non-thin-walled tapered hole portion, it is difficult to form a fine nozzle outlet. For example, a well-known manufacturing method cannot manufacture a nozzle outlet having a fine diameter of less than 45 μm and a precision nozzle having a tapered hole portion that extends from the nozzle outlet along the inner diameter in a direction increasing toward the injection port.

[0083] Figure 3 FIG. is a schematic cross-sectional view of a precision nozzle as another example of the precision nozzle of the present invention. This precision nozzle 11 also has a through hole 13 that penetrates from a circular injection port 12 to a circular nozzle outlet 14, but the shape of the through hole 13 is different from that of the through hole 3 in Figure 1 and Figure 2 That is, in this precision nozzle 11, the aforementioned through hole 13 is formed only by a tapered hole portion that continuously extends along the inner diameter in a direction increasing from the aforementioned nozzle outlet 14 to the aforementioned injection port 12.

[0084] Figure 4 FIG. is a schematic cross-sectional view of a precision nozzle as another example of the precision nozzle of the present invention. In the example of this precision nozzle 21, the shape of the through hole 23 that penetrates from a circular injection port 22 to a circular nozzle outlet 24 is the same as that of the precision nozzle in Figure 1 , except that the outer peripheral shape of the nozzle 21 is cylindrical (cylindrical). Figure 1 The precision nozzle of Figure 4 is usually formed by grinding the method of the precision nozzle of

[0085] Figure 5 FIG. is a schematic cross-sectional view of a precision nozzle as another example of the precision nozzle of the present invention. This precision nozzle 31 has a through hole 33 that penetrates from a circular injection port 32 to a circular nozzle outlet 34. The through hole 33 includes a first tapered hole portion 33b and a second tapered hole portion 33a. The first tapered hole portion 33b extends from the aforementioned nozzle outlet 34 along the inner diameter in a direction increasing toward the aforementioned injection port 32, and the second tapered hole portion 33a extends from the upstream end of the first tapered hole portion 33b along the inner diameter in a direction increasing toward the aforementioned injection port 32. In this example, the inclination angle of the second tapered hole portion 33a is formed to be larger than the inclination angle of the first tapered hole portion 33b.

[0086] The cross-sectional shape (the cross-sectional shape perpendicular to the length direction or the axial direction) of the through hole (especially the tapered hole portion) is not limited, and examples thereof include: circular, elliptical, polygonal, etc. Among these cross-sectional shapes, anisotropic shapes such as elliptical and rectangular can be used, but isotropic shapes such as circular, square, and regular hexagon are more preferred, and circular is particularly preferred. The shape of the ejection port is the same.

[0087] When the shape of the ejection port (hole shape) is circular, since a specific powder compacting step, an electrical discharge machining step, and a polishing step are combined in the method of the present invention, the circular shape of the ejection port can be formed into a circular shape with a small roundness. The roundness of the ejection port can be 5 μm or less (for example, about 0.1 to 5 μm), more preferably 4 μm or less (for example, 0.3 to 4 μm), still more preferably 3 μm or less, yet more preferably 1 μm or less, and most preferably 0.5 μm or less. If the roundness is too large, there is a concern that the function of the precision nozzle will decline.

[0088] When the shape of the ejection port is circular, the roundness of the ejection port can be 0.3 times or less with respect to the diameter of the ejection port, more preferably 0.2 times or less, still more preferably 0.1 times or less, for example, 0.001 to 0.3 times, more preferably 0.005 to 0.25 times, still more preferably 0.01 to 0.2 times, yet more preferably 0.03 to 0.15 times, and most preferably 0.05 to 0.1 times. If the ratio of the roundness to the diameter is too large, there is a concern that the function of the precision nozzle will decline.

[0089] In addition, in this specification and the claims, the roundness of the ejection port can be measured according to JIS B 0621-1984. Specifically, an optical image measuring device ("Smart Scope ZIP-300" manufactured by OGP Corporation) can be used for measurement.

[0090] When the outer shape of the precision nozzle of the ejection port is isotropic (especially circular) and the shape of the ejection port is circular, the concentricity between the outer shape and the ejection port can be 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less, yet more preferably 5 μm or less, for example, 0.1 to 10 μm, more preferably 0.3 to 8 μm, still more preferably 0.5 to 7 μm, yet more preferably 1 to 6 μm, and most preferably 1.5 to 5 μm. If the concentricity is too large, there is a concern that the function of the precision nozzle will decline.

[0091] In addition, in this specification and the claims, the concentricity is defined in accordance with JIS B0021-1998. Specifically, an optical image measuring device (the "Smart Scope ZIP-300" manufactured by OGP) can be used for measurement. Further, in this specification and the claims, the concentricity refers to the deviation between the center of the circle of the aforementioned outer shape and the center of the circle of the ejection port (the distance between the center of the outer circle and the center of the inner circle).

[0092] The diameter φ of the ejection port of the precision nozzle of the present invention (the aperture diameter of the outlet on the downstream side of the tapered hole portion) can be less than 45 μm, more preferably less than 40 μm, still more preferably less than 35 μm, and yet more preferably less than 30 μm. In addition, the diameter φ of the ejection port can be 1 μm or more. Particularly in the precision nozzle, the diameter of the ejection port can be 25 μm or less (especially 20 μm or less), for example, 1 to 25 μm, more preferably 2 to 20 μm, still more preferably 3 to 10 μm, and yet more preferably 4 to 7 μm.

[0093] In addition, in this specification and the claims, the diameter φ of the ejection port can be measured using an optical image measuring device (the "Smart Scope ZIP-300" manufactured by OGP), etc. The diameter of the ejection port refers to the maximum diameter, which is the diameter in the case of a circle and the major axis in the case of a polygon or an anisotropic shape. In Figure 6 and Figure 7 shows the diameter φ of the ejection port of the precision nozzle of Figure 4 and Figure 5 .

[0094] The length in the nozzle axis direction of the tapered hole portion (the depth of the tapered hole portion) L can be 1 mm or more and 30 mm or less. That is, the depth of the tapered hole portion can be selected from the range of about 1 to 30 mm, for example, 1 to 20 mm, more preferably 2 to 10 mm, still more preferably 2.5 to 8 mm, yet more preferably 3 to 5 mm, and most preferably 3.5 to 4.5 mm. If the depth of the tapered hole portion is too short, there is a concern that it will be difficult to manufacture a minute ejection port.

[0095] In addition, in this specification and the claims, the length in the nozzle axis direction of the tapered hole portion refers to the shortest distance between the opening portion on the upstream side of the tapered hole portion and the center of the ejection port. In Figure 6 and Figure 7 shows the depth L of the tapered hole portion of the precision nozzle of Figure 4 and Figure 5 .

[0096] The precision nozzle of the present invention is characterized in that: with respect to the diameter of the ejection port, the length of the tapered hole portion is large, and it is a precision nozzle with a non-thin wall. It is difficult to form a precision nozzle with a non-thin wall tapered hole portion from cemented carbide. In particular, it is impossible to manufacture a tapered hole portion with an ejection port diameter less than 45 μm from cemented carbide by well-known machining methods. However, if the precision nozzle is manufactured using the manufacturing method of the present invention, it is possible to form a tapered hole portion with a fine ejection port.

[0097] In the precision nozzle of the present invention, the depth L of the tapered hole portion is large with respect to the diameter φ of the ejection port, and the tapered hole portion has a non-thin wall. The depth L of the tapered hole portion with respect to the diameter φ of the ejection port can be 10 times or more, for example, 30 times or more, more preferably 50 times or more, still more preferably 80 times or more, yet more preferably 100 times or more, and most preferably 200 times or more. For example, it can be 50 to 10,000 times (especially 100 to 1,000 times).

[0098] The inclination angle θ [the angle between the nozzle axis and the inclined wall (the inner wall of the tapered hole portion)] of the tapered hole portion is, for example, 3 to 60° with respect to the nozzle axis, more preferably 4 to 50°, still more preferably 5 to 30°, yet more preferably 7 to 20°, and most preferably 8 to 15°. If the inclination angle θ is too small, there is a concern that the function of precision nozzles such as reflow nozzles using solder balls will be reduced. On the contrary, if the inclination angle θ is too large, there is a concern that it will be difficult to form a fine ejection port.

[0099] The smoothness of the inner wall of the tapered hole portion is excellent. The arithmetic mean roughness Ra of the inner wall surface of the tapered hole portion is, for example, 5 to 1000 μm, more preferably 10 to 800 μm, still more preferably 30 to 500 μm, yet more preferably 50 to 300 μm, and most preferably 100 to 200 μm. In Figure 6 shows the inner wall 21b in the Figure 4 precision nozzle, and in Figure 7 shows the inner walls 31b, 31c in the Figure 5 precision nozzle.

[0100] The front end surface (the front end surface on the downstream side) of the ejection port of the precision nozzle of the present invention is, as described later, excellent in smoothness because it is obtained through a grinding step. The arithmetic mean roughness Ra of the front end surface (the ground surface) of the ejection port is, for example, 1 to 100 μm, more preferably 5 to 50 μm, still more preferably 8 to 40 μm, yet more preferably 10 to 30 μm, and most preferably 15 to 25 μm. In Figure 6 shows the front end surface 21a of the ejection port in the Figure 4 precision nozzle, and in Figure 7 shows the front end surface 31a of the ejection port in the Figure 5 precision nozzle.

[0101] In addition, in this specification and the claims, the arithmetic mean roughness Ra of the inner wall surface of the tapered hole portion and the front end surface of the ejection port can be measured according to the method of JIS B 0601-2001. Specifically, it can be measured using a profile / shape measuring machine ("SURFCOM 2600G-13" manufactured by Tokyo Seimitsu Co., Ltd.).

[0102] The shape of the through-hole of the precision nozzle of the present invention only needs to be a shape including the aforementioned tapered hole portion, and there is no particular limitation. The shape of the hole on the upstream side of the tapered hole portion is also not limited, and can be appropriately selected according to the use, the type of the ejected body, etc. Therefore, the shape of the through-hole can be, in addition to Figure 1 or Figure 2 the shapes shown, also, for example: a shape in which the aforementioned tapered hole portion is combined with other tapered hole portions, a shape in which the aforementioned tapered hole portion is combined with a plurality of other tapered hole portions, a shape in which the aforementioned tapered hole portion is combined with a non-tapered hole portion (especially a cylindrical hole portion) and other tapered hole portions, etc.

[0103] The non-tapered hole portion only needs to be a shape corresponding to the tapered hole portion, and there is no particular limitation. In addition to the cylindrical hole portion, the inner shape can include non-tapered hole portions such as an elliptical columnar shape or a polygonal columnar shape.

[0104] In the case of a shape in which the tapered hole portion is combined with a non-tapered hole portion (especially a cylindrical hole portion), the inner diameter of the flow path of the non-tapered hole portion (especially the cylindrical flow path) is, for example, 0.5 to 10 mm, more preferably 0.8 to 5 mm, still more preferably 1 to 3 mm, and even more preferably 1.2 to 2 mm.

[0105] [Powder Compression Molding Step]

[0106] The manufacturing method of the precision nozzle of the present invention includes a powder compression molding step, in which the raw material powder is compression molded using a transfer mold for forming the through-hole of the nozzle to obtain a molded body, and the molded body has an opening portion corresponding to the aforementioned injection port and an unpenetrated hole portion.

[0107] (Raw Material Powder)

[0108] The raw material powder can be appropriately selected according to the type of cemented carbide. Generally, the constituent components of cemented carbide are used in the form of particles respectively. In WC-based alloys, in addition to the binder component particles, other metal carbide particles and other metal particles are also used as raw material powder as needed.

[0109] The average particle size of the WC particles is, for example, 0.1 to 15 μm, more preferably 0.12 to 12 μm, still more preferably 0.2 to 10 μm.

[0110] Since the combined phase is formed by melting, the average particle diameter of the combined component particles (especially Co particles) is not particularly limited, and is, for example, 0.1 to 5 μm, more preferably 0.5 to 3 μm, and still more preferably 1 to 2.5 μm.

[0111] The average particle diameters of other metal carbide particles and other metal particles are, for example, 0.1 to 5 μm, more preferably 0.5 to 3 μm, and still more preferably 1 to 2.5 μm, respectively.

[0112] The usage amounts of the raw material powders of these WC-based alloys are the same as the ratios of the constituent components in the above-mentioned cemented carbide.

[0113] In powder pressing (compression molding), in addition to these raw material powders, a binder may also be formulated. As the binder, a binder that can be removed by heating during pre-sintering or sintering is more preferably used. As such a binder, for example, linear or branched aliphatic hydrocarbons such as paraffin, wax, or wax, polyethylene glycol, etc. can be cited. These binders can also be in a granular form. In addition, these binders can also be formulated together with alcohols such as ethanol and / or benzine.

[0114] With respect to 100 parts by mass of the raw material powder, the ratio of the binder can be 20 parts by mass or less, more preferably 0.1 to 10 parts by mass, and still more preferably 0.2 to 7 parts by mass.

[0115] (Compression molding)

[0116] In the compression molding of the raw material powder, a molded body (powder molded body) can be obtained by using a transfer mold for forming a through hole of a nozzle. The molded body has an opening portion corresponding to the aforementioned injection port and has an unpenetrated hole portion (corresponding to a so-called "bottom hole").

[0117] Regarding an example of the powder pressing step, it is illustrated by Figure 8 As shown in Figure 8 In the powder pressing step, first, in a cylindrical or other tubular mold formed by a die 42 and a lower punch 43, the raw material powder 41 for forming the cemented carbide is filled Figure 8 (part (a)). Next, the upper punch 44 with a press pin 45 installed as a transfer mold is inserted into the aforementioned tubular mold and the raw material powder 41 is pressurized. As a result, the press pin 45 penetrates into the interior of the filler of the raw material powder 41, and thus the shape of the press pin 45 is transferred to the molded body (or powder molded body) of the raw material powder 41 Figure 8 (part (b)). Finally, the powder molded body of the raw material powder 41 is taken out from the aforementioned tubular mold, and a cylindrical powder molded body 46 having the aforementioned hole portion is obtainedFigure 8 part (c) of

[0118] The press pin 45 as a transfer mold has a shape in which the front end of a cylinder is formed into a cone. In the powder compression molding step, for the raw material powder 41 filled in the mold, the press pin 45 having the aforementioned shape is inserted from the front end of the cone while applying pressure, whereby the raw material powder 41 can be compacted, and the shape of the press pin 45 as a transfer mold can be transferred to the powder molded body of the raw material powder 41 as the shape of the aforementioned cavity portion. The cavity portion formed in the above manner is different from the through-hole of the target nozzle. By forming a cavity portion that does not penetrate the powder molded body and through a step of combining a die sinking electrical discharge machining step and a grinding step described later, a minute ejection port can be formed at the front end of the bottom of the aforementioned cavity portion.

[0119] The shape of the transfer mold only needs to be a shape capable of transferring a powder molded body having an opening corresponding to the aforementioned injection port and having a non-penetrating cavity portion, and there is no particular limitation. This is because, by forming a cavity portion that does not penetrate the powder molded body and through the grinding step described later, it is possible to grind from the opposite side of the opening to form a minute ejection port. In particular, by setting the front end shape (bottom shape) of the cavity portion to a minute shape with a pointed tip, it is possible to easily form an ejection port with a minute diameter.

[0120] The shape of such a transfer mold only needs to correspond to the shape of the through-hole. From the viewpoint of easily forming a minute ejection port of a precision nozzle, it is more preferable that it corresponds to the shape of the aforementioned through-hole and the shape of the conical portion corresponding to the aforementioned conical hole portion is a conical shape. That is, among the shapes corresponding to the shape of the aforementioned through-hole in the shape of the transfer mold, only the shape of the portion corresponding to the aforementioned conical hole portion is substantially corresponding to the shape of the aforementioned through-hole, but it can also be a shape that does not correspond at all (in the shape of the aforementioned conical hole portion, a conical shape in which the front end portion extends from the ejection port). The conical portion of the transfer mold also easily forms a minute ejection port by forming the same cone angle as the conical hole portion of the aforementioned precision nozzle. In addition, the powder molded body shrinks by about 20% to 30% in the sintering step described later, so the shape of the transfer mold can be formed into a shape slightly larger than the shape of the through-hole according to the shrinkage rate.

[0121] From the viewpoint of easily forming a minute ejection port of a precision nozzle, it is more preferable to reduce the front end diameter of the conical portion of the transfer mold. The aforementioned front end diameter can be selected according to the target diameter of the ejection port, for example, it can be 10 μm or less (for example, 1 to 10 μm), more preferably 7 μm or less (for example, 2 to 7 μm), and even more preferably 5 μm or less (for example, 3 to 5 μm). If the front end diameter is too large, there is a concern that it will be difficult to easily manufacture a precision nozzle having a minute ejection port diameter.

[0122] The molding pressure for compression molding is, for example, 50 to 300 MPa, more preferably 100 to 250 MPa, and even more preferably 150 to 200 MPa.

[0123] [Sintering step]

[0124] The method for manufacturing the precision nozzle of the present invention further includes a sintering step, which sinters the powder compact obtained in the aforementioned powder pressing and molding step to obtain a sintered body having an opening corresponding to the aforementioned injection port and having an unpenetrated cavity.

[0125] In the sintering step, by melting the binder component particles to form a liquid phase, a sintered body that refines and integrates the aforementioned powder compact can be obtained. However, if necessary, the aforementioned powder compact can be heated at a temperature lower than the main sintering temperature for pre-sintering (temporary sintering) as a pre-step for the main sintering of melting the binder component particles. When the powder compact contains a binder, the binder can be removed by pre-sintering.

[0126] The temperature for pre-sintering is, for example, 100 to 1000 °C, more preferably 300 to 900 °C, and even more preferably 500 to 800 °C. The pressure for pre-sintering can be under normal pressure or reduced pressure, and more preferably under reduced pressure. The time for pre-sintering is, for example, 2 to 48 hours, more preferably 4 to 12 hours, and even more preferably 6 to 10 hours.

[0127] The temperature for main sintering is, for example, 1200 to 1600 °C, more preferably 1250 to 1550 °C, and even more preferably 1300 to 1500 °C. The pressure for main sintering can be under normal pressure or reduced pressure (or under vacuum), and can also be under normal pressure or increased pressure. The time for main sintering is, for example, 1 to 48 hours, more preferably 2 to 24 hours, and even more preferably 3 to 20 hours.

[0128] [Electrical discharge machining step]

[0129] The method for manufacturing the precision nozzle of the present invention further includes an electrical discharge machining step (die sinking electrical discharge machining step), which inserts an electrode into the cavity of the aforementioned sintered body for electrical discharge machining.

[0130] The refined sintered body obtained by sintering the powder compact obtained in the powder pressing and forming step is processed to a state close to the target precision nozzle (near net shape) by using a transfer mold and a shrinkage ratio. However, in the present invention, in order to manufacture a precision nozzle that requires a precise passage shape of the ejected body and a fine ejection port, it is further processed to a shape close to the through-hole of the target precision nozzle by engraving electrical discharge machining. Accordingly, a precision nozzle having a minute ejection port can be manufactured. In particular, in the present invention, by using a specific electrode in the engraving electrical discharge machining step, a precision nozzle having an ejection port with a diameter of less than 30 μm can be manufactured with good precision via the polishing step described later, and an ejection port with a diameter of 20 μm or less, which cannot be manufactured by well-known manufacturing methods, can also be manufactured. At this time, as the effect of near net shape with the transfer mold, the electrode consumption of the engraving electrical discharge machining is small, the precision machining accuracy can be improved, and the cost can be reduced.

[0131] Utilize Figure 9 A series of processes from the sintering step to the engraving electrical discharge machining step will be described. As Figure 9 shown, the powder compact 46 Figure 9 (part (a)) obtained in the powder pressing and forming step will be refined and integrated in the sintering step to obtain a sintered body 47 Figure 9 (part (b)) having a near net shape cavity portion 47a. The cavity portion 47a is machined by electrical discharge using an electrode 48 having a shape corresponding to the through-hole of the precision nozzle, and by finely machining the inner wall of the cavity portion 47a, the shape of the electrode 48 is precisely transferred to the cavity portion 47a of the sintered body 47 Figure 9 (part (c)).

[0132] The electrode 48 also has a shape corresponding to the punch 45 in the powder pressing and forming step described above, and has a shape in which the front end of a cylinder is formed into a cone. In the engraving electrical discharge machining step, the electrode 48 having such a conical shape is used to transfer the shape of the electrode, whereby the cavity portion 47a of the sintered body 47 is made closer to the shape of the through-hole of the target precision nozzle, and a minute ejection port is easily formed in the polishing step described later.

[0133] From the perspective of facilitating the formation of the shape of the target through-hole, the shape of the electrode is preferably the shape corresponding to the aforementioned through-hole. From the perspective of facilitating the opening of the minute ejection orifice in the subsequent grinding step, it is preferably the shape corresponding to the aforementioned through-hole, and the shape of the conical portion corresponding to the aforementioned conical hole portion is a conical shape. That is, in the shape of the electrode, among the shapes corresponding to the shape of the aforementioned through-hole, only the shape of the portion corresponding to the aforementioned conical hole portion is substantially corresponding to the shape of the aforementioned through-hole, but it may also be a shape that is not corresponding at all (in the shape of the aforementioned conical hole portion, it is a conical shape in which the tip extends from the ejection orifice). Therefore, it is preferably that the cone angle of the conical portion of the electrode is the same as the cone angle of the conical hole portion of the aforementioned precision nozzle.

[0134] From the perspective of facilitating the formation of the minute ejection orifice of the precision nozzle, it is preferably to reduce the tip diameter of the conical portion of the electrode. The aforementioned tip diameter can be selected according to the target diameter of the ejection orifice. For example, it can be 10 μm or less (for example, 1 to 10 μm), preferably 7 μm or less (for example, 2 to 7 μm), and more preferably 5 μm or less (for example, 3 to 5 μm). If the tip diameter is too large, there is a concern that it will be difficult to easily manufacture a precision nozzle with a minute ejection orifice diameter.

[0135] As the material of the electrode, it is preferably to contain tungsten W, more preferably tungsten alone, an alloy of tungsten and other metals (for example, an alloy of tungsten and copper), and tungsten alone is more preferred.

[0136] In the electrical discharge machining, the gap (discharge area) between the electrode and the hole portion is, for example, 10 to 30 μm, preferably 10 to 20 μm, and more preferably 5 to 10 μm.

[0137] As the conditions for the electrical discharge machining, for example, considering productivity and accuracy maintenance, it is preferably to use 5 to 8 electrodes for machining.

[0138] [Grinding step]

[0139] The method for manufacturing the precision nozzle of the present invention includes a grinding step of grinding the sintered body that has been subjected to electrical discharge machining through the aforementioned engraving electrical discharge machining from the side opposite to the opening portion that serves as the injection port, so as to form an opening for the ejection orifice. A hole portion having a shape corresponding to the through-hole of the precision nozzle is formed inside the sintered body obtained by the aforementioned engraving electrical discharge machining, but the tip portion of the cone corresponding to the bottom of the hole portion does not penetrate the sintered body. Therefore, in the grinding step, the sintered body is ground to the tip portion of the cone that is the hole portion to form an opening for the ejection orifice.

[0140] As the grinding method, a conventional grinding method can be used. For example, a grinding machine (surface grinder, etc.) equipped with a disk-shaped grinding stone can be used.

[0141] In the foregoing grinding step, there are no particular limitations on the method for confirming the presence or absence of holes that become the ejection ports and the diameters thereof, and examples thereof include: a method of confirming by allowing a gas or liquid to flow through, a method of confirming by using a camera to obtain an image, etc. Among these methods, from the viewpoints of simplicity and the like, the method of using a camera to obtain an image for confirmation is more preferable.

[0142] Using Figure 10 A grinding step using a method of confirming by taking an image of the ground surface with a camera will be described. In the grinding step, for the sintered body 47 obtained in the die sinking electrical discharge machining step, a grinding machine 49 equipped with a disk-shaped grinding stone is used, and the surface of the aforementioned sintered body 47 is ground by moving the disk-shaped grinding stone while rotating Figure 10 part (a)]. After grinding the aforementioned surface for a predetermined time from the opposite side (back surface) of the opening portion that becomes the injection port, the image of the ground surface is confirmed with a camera 50 Figure 10 part (b)]. As a result of confirming the image, when holes cannot be confirmed on the ground surface, grinding is repeated for a predetermined time and / or a predetermined distance until holes can be confirmed. Then, when holes can be confirmed, the diameter is measured with a measuring machine, and if the target ejection port diameter is not reached, grinding is repeated for a predetermined time and / or a predetermined distance until the target diameter can be confirmed, whereby a precision nozzle 51 having a target ejection port can be manufactured.

[0143] In the grinding method using a grinding machine equipped with a disk-shaped grinding stone, the circumferential speed of the disk-shaped grinding stone is, for example, 15 to 35 m / s, more preferably 20 to 30 m / s, and still more preferably about 24 to 28 m / s. In addition, the rotational speed of the rotating shaft for rotating the disk-shaped grinding stone is, for example, 1400 to 2600 rpm, more preferably 1600 to 2400 rpm, and still more preferably 1800 to 2200 rpm. If the speed is too low, there is a concern about a decrease in productivity. On the contrary, if the speed is too high, there is a concern about difficulty in adjusting the diameter of the ejection port.

[0144] As the grinding stone, a conventional grinding stone can be used, and examples thereof include: diamond resin (SDC, metal-coated synthetic diamond) based grinding stones, diamond resin (SD, synthetic diamond) based grinding stones, etc. The size of the abrasive grains (grit size of the grinding stone) is, for example, #170 to #2000, more preferably #200 to #1800, and still more preferably #325 to #1500. If the particle diameter is too small, there is a concern about a decrease in productivity. On the contrary, if the particle diameter is too large, there is a concern about difficulty in adjusting the diameter of the ejection port.

[0145] As the camera, a digital camera such as a CCD camera, a CMOS camera, a laser camera, a thermal imaging camera, a stereovision camera, etc. can be used. From the viewpoint of high image processing accuracy, among the above cameras, a CCD camera is more preferable.

[0146] There is no particular limitation on the method for confirming the hole and its diameter of the ground surface. It can be a method of visually observing the image on the monitor, or a method of analyzing the data that has been image-processed and read by an information analysis device (such as a personal computer), and controlling it to a predetermined diameter in association with the grinding speed.

[0147] The precision nozzle obtained through the grinding step can be a nozzle for ejecting various fluids, such as heated or unheated fluids. In addition, the heated fluid can also be a fluid that is heated and melted (for example, solder balls are injected from the injection port, and the solder balls are melted in the hole by a heating device such as laser irradiation to form solder paste), etc.

[0148] [Examples]

[0149] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0150] Example 1

[0151] [Manufacturing a punch pin]

[0152] Using an optical profiling grinder, a pin with a cutting edge that has as little flat band as possible at the front end is manufactured by profile grinding (PG) of a cemented carbide alloy. A micrograph of the front end of the obtained punch pin (transfer mold) is shown in Figure 11 . The front end diameter of the punch pin is 5 μm.

[0153] [Manufacturing an electrode]

[0154] Using an optical profiling grinder, a pin with a cutting edge that has as little flat band as possible at the front end is manufactured by PG processing of a tungsten W round bar. A micrograph of the front end and its enlarged part of the obtained electrode is shown in Figure 12 . The front end diameter of the electrode is 4 μm.

[0155] [Powder pressing step]

[0156] A mixed powder manufactured by mixing 92 g of powdered tungsten carbide WC (average particle size of about 2.5 μm), 8 g of powdered cobalt Co, and 0.8 g of paraffin is filled in the mold formed by the die and the lower punch shown in Figure 8 , and pressurized at 150 MPa using the upper punch equipped with the aforementioned punch pin to obtain a cylindrical powder compact having a cavity.

[0157] [Sintering step]

[0158] The obtained powder compact is sintered at 1400 °C for 5 hours under vacuum to obtain a sintered body.

[0159] [Electric Discharge Machining Step]

[0160] Using an engraving electric discharge machining machine (AQ35L manufactured by Sodick Co., Ltd.) and an electrode formed into a cutting edge as much as possible, the sintered body is subjected to multiple engraving electric discharge machining operations divided into rough machining, semi-finishing, and finishing.

[0161] [Grinding Step]

[0162] Using a grinding machine equipped with a disk-shaped grinding stone (“TECSTAR 52” manufactured by AMADA MACHINERY Co., Ltd.), in the grinding step, while using a CCD camera to confirm the grinding surface by image, the sintered body that has been subjected to electric discharge machining is processed. As a result of confirming the image, when a hole cannot be confirmed on the grinding surface, grinding and confirmation of the image of the grinding surface are repeated until a hole can be confirmed. A micrograph of the tip of the precision nozzle where the hole penetrates and the front end of the precision nozzle with an ejection port can be observed for the first time is shown in Figure 13 . The diameter of the ejection port is φ5μm. The small white circular opening that can be confirmed in the center of the photograph is the ejection port with a diameter of 5μm. The depth L of the tapered hole portion of the obtained precision nozzle is 4240μm, and the aspect ratio of the depth of the tapered hole portion to the diameter φ of the ejection port (L / φ) is 848. The inclination angle θ of the aforementioned tapered hole portion is 10 degrees.

[0163] By further repeating grinding, a precision nozzle having a target ejection port is manufactured. A micrograph of the cross-section of the tip of the obtained precision nozzle is shown in Figure 14 . It becomes tapered toward the ejection port, and the diameter of the ejection port is φ20μm. The arithmetic mean roughness Ra of the tapered inner wall surface is 128μm, and the arithmetic mean roughness Ra of the front end surface is 20μm.

[0164] Example 2

[0165] An electrically discharged sintered body is manufactured in the same manner as in Example 1. In the grinding step, the timing and frequency of confirming the image of the grinding surface are changed, and finally, a precision nozzle with an ejection port diameter φ of 39.1μm is manufactured. The results of measuring the diameter and the depth of the tapered hole portion at each confirmation timing, calculating the aspect ratio, and measuring the roundness of the ejection port are shown in Table 1. In addition, for the grinding surfaces confirmed at the beginning and the end, the concentricity of the tip of the precision nozzle (the concentricity between the outer shape of the precision nozzle of the ejection port and the ejection port) is also evaluated.

[0166] [Table 1]

[0167] Table 1

[0168]

[0169] As can be seen from the results in Table 1, in Example 2, in the precision nozzle with a tapered hole portion having a large aspect ratio, a discharge port with a fine diameter and a small roundness can be formed. The microscopic photograph of the cross-section of the front end portion of the precision nozzle obtained in the second confirmation is shown in Figure 15 . It can be confirmed that a circular discharge port is formed in the center of the photograph.

[0170] Example 3

[0171] A sintered body processed by electric discharge machining was manufactured in the same manner as in Example 1. In the grinding step, the timing and frequency of confirming the image of the ground surface were changed, and finally, a precision nozzle with a discharge port diameter φ of 39.5 μm was manufactured. The results of measuring the diameter and the depth of the tapered hole portion, calculating the aspect ratio, and measuring the roundness of the discharge port at each confirmation timing are shown in Table 2.

[0172] [Table 2]

[0173] Table 2

[0174]

[0175]

[0176] As can be seen from the results in Table 2, in Example 3, in the precision nozzle with a tapered hole portion having a large aspect ratio, a discharge port with a fine diameter and a small roundness can be formed. The microscopic photograph of the cross-section of the front end portion of the precision nozzle obtained in the second confirmation is shown in Figure 16 . It can be confirmed that a circular discharge port is formed in the center of the photograph.

[0177] Example 4

[0178] A sintered body processed by electric discharge machining was manufactured in the same manner as in Example 1. In the grinding step, the timing and frequency of confirming the image of the ground surface were changed, and finally, a precision nozzle with a discharge port diameter φ of 39.3 μm was manufactured. The results of measuring the diameter and the depth of the tapered hole portion, calculating the aspect ratio, and measuring the roundness of the discharge port at each confirmation timing are shown in Table 3. In addition, the concentricity of the front end portion of the precision nozzle was also evaluated for the finally confirmed ground surface.

[0179] [Table 3]

[0180] Table 3

[0181]

[0182] As can be seen from the results in Table 3, in Example 4, in the precision nozzle with a tapered hole portion having a large aspect ratio, a discharge port with a fine diameter and a small roundness can be formed. The microscopic photograph of the cross-section of the front end portion of the precision nozzle obtained in the final confirmation is shown in Figure 17 . It can be confirmed that a circular discharge port is formed in the center of the photograph.

[0183] Example 5

[0184] A sintered body subjected to electrical discharge machining was manufactured in the same manner as in Example 1. In the grinding step, the timing and frequency of confirming the image of the ground surface were changed, and finally, a precision nozzle with a nozzle diameter φ of 39.2 μm was manufactured. The results of measuring the diameter at each confirmation timing, the depth of the tapered hole portion, calculating the aspect ratio, and measuring the roundness of the nozzle outlet are shown in Table 4. In addition, the concentricity of the front end portion of the precision nozzle was also evaluated for the finally confirmed ground surface.

[0185] [Table 4]

[0186] Table 4

[0187]

[0188] From the results in Table 4, it can be seen that in Example 5, in the precision nozzle with a tapered hole portion having a large aspect ratio, a nozzle outlet with a fine diameter and a small roundness can be formed. A micrograph of the cross-section of the front end portion of the precision nozzle obtained from the final confirmation is shown in Figure 18 . It can be confirmed that a circular nozzle outlet is formed in the center of the photograph.

[0189] Example 6

[0190] A sintered body subjected to electrical discharge machining was manufactured in the same manner as in Example 1, except that multiple finish machinings were added during the electrical discharge machining. Using a grinding machine equipped with a disk-shaped grindstone, in the grinding step, while confirming the ground surface with an image using a CCD camera, the sintered body subjected to electrical discharge machining was processed. The results of measuring the diameter at each confirmation timing, the depth of the tapered hole portion, calculating the aspect ratio, and measuring the roundness of the nozzle outlet are shown in Table 5. In addition, the concentricity of the front end portion of the precision nozzle was also evaluated for the initially and finally confirmed ground surfaces.

[0191] [Table 5]

[0192] Table 5

[0193]

[0194] From the results in Table 5, it can be seen that in Example 6, in the precision nozzle with a tapered hole portion having a large aspect ratio, a nozzle outlet with a fine diameter and a small roundness can be formed. A micrograph of the cross-section of the front end portion of the precision nozzle obtained from the final confirmation is shown in Figure 19 . It can be confirmed that a circular nozzle outlet is formed in the center of the photograph.

[0195] Example 7

[0196] Manufacture the sintered body by electrical discharge machining in the same manner as in Example 6. Using this sintered body, in the grinding step, change the timing for confirming the image of the ground surface, and manufacture a precision nozzle with an orifice diameter φ of 42.5 μm. The depth L of the tapered hole portion of the obtained precision nozzle is 4133 μm, and the ratio of the depth of the tapered hole portion to the orifice diameter φ (aspect ratio L / φ) is 97. The roundness of the orifice is 0.8 μm, and the concentricity of the tip of the precision nozzle is 3 μm.

[0197] Example 8

[0198] Manufacture the sintered body by electrical discharge machining in the same manner as in Example 6. In the grinding step, change the timing and frequency for confirming the image of the ground surface, and finally manufacture a precision nozzle with an orifice diameter φ of 39.9 μm. The results of measuring the orifice diameter and the depth of the tapered hole portion at each confirmation timing, calculating the aspect ratio, and measuring the roundness of the orifice and the concentricity of the tip of the precision nozzle are shown in Table 6.

[0199] [Table 6]

[0200] Table 6

[0201]

[0202] From the results in Table 6, it can be seen that in Example 8, in the precision nozzle with a tapered hole portion having a large aspect ratio, an orifice with a fine diameter and a small roundness can be formed. A micrograph of the cross-section of the tip of the precision nozzle obtained from the final confirmation is shown in Figure 20 . It can be confirmed that a circular orifice is formed in the center of the photograph.

[0203] Example 9

[0204] In the powder pressing step, manufacture the sintered body by electrical discharge machining in the same manner as in Example 1, except that finer powdered tungsten carbide WC (average particle size of about 0.8 μm) is used as the powdered tungsten carbide WC. Using a grinding machine equipped with a disk-shaped grindstone, in the grinding step, while using a CCD camera to confirm the ground surface by image, machine the sintered body that has been electrically discharge machined. The results of measuring the orifice diameter φ, the depth L of the tapered hole portion, and calculating the aspect ratio at each confirmation timing are shown in Table 7. In addition, evaluate the concentricity of the tip of the precision nozzle for the ground surface confirmed for the first time, evaluate the roundness of the orifice for the ground surface confirmed for the fifth time, and evaluate the roundness of the orifice and the concentricity of the tip of the precision nozzle for the ground surfaces confirmed for the first and last times.

[0205] [Table 7]

[0206] Table 7

[0207]

[0208] As can be seen from the results in Table 7, in Example 9, in the precision nozzle with a conical hole portion having a large aspect ratio, an ejection port with a fine diameter and a small roundness can be formed. A micrograph of the cross-section of the front end portion of the obtained precision nozzle in the final confirmation is shown in Figure 21 . It can be confirmed that a circular ejection port is formed in the center of the photograph.

[0209] Example 10

[0210] A precision nozzle with an ejection port diameter of φ5 μm (roundness of 0.4 μm) was obtained in the same manner as in Example 1, except that multiple finish machinings were added during electrical discharge machining.

[0211] [Industrial Applicability]

[0212] The precision nozzle of the present invention can be used as various precision nozzles having fine ejection ports. For example, in the manufacturing process of conductor devices, as a nozzle for electronic parts used for assembling small parts or mounting on a substrate, etc., it can be applied to reflow nozzles, suction nozzles, solder ejection nozzles, etc. Among them, it is particularly suitable as a reflow nozzle for melting and ejecting solder balls.

[0213] Explanation of Reference Numerals

[0214] 1 Precision nozzle

[0215] 2 Injection port

[0216] 3 Through hole

[0217] 3a Cylindrical hole portion

[0218] 3b Conical hole portion

[0219] 4 Ejection port.

Claims

1. A manufacturing method of a precision nozzle, wherein the precision nozzle is formed of a cemented carbide, has a through hole penetrating from an injection port to a discharge port, and the through hole at least includes a tapered hole portion starting from the discharge port and extending in a direction where the inner diameter increases toward the injection port. The manufacturing method includes the following steps: Powder compression molding step: Using a transfer mold for forming the through hole, raw material powder is compressed and molded to obtain a molded body, which has an opening corresponding to the injection port and an unpenetrated cavity portion; Sintering step: Sintering the molded body to obtain a sintered body corresponding to the molded body; Electrical discharge machining step: Inserting an electrode into the cavity portion of the sintered body for electrical discharge machining; And Grinding step: Grinding the sintered body that has undergone electrical discharge machining from the side opposite to the opening that becomes the injection port, so as to form an opening at the discharge port.

2. The manufacturing method according to claim 1, wherein, the cross-sectional shape of the through hole is circular, elliptical or polygonal.

3. The manufacturing method according to claim 2, wherein, the cross-sectional shape of the through hole is circular.

4. The manufacturing method according to any one of claims 1 to 3, wherein, in the powder compression molding step, the shape of the transfer mold corresponds to the shape of the through hole, and the shape of the tapered portion corresponding to the tapered hole portion is conical, elliptical conical or polygonal conical.

5. The manufacturing method according to claim 4, wherein, the shape of the tapered portion corresponding to the tapered hole portion is conical.

6. The manufacturing method according to claim 5, wherein, the front end diameter of the conical portion of the transfer mold corresponding to the tapered hole portion is 5 μm or less.

7. The manufacturing method according to any one of claims 1 to 3, wherein, in the electrical discharge machining step, the shape of the electrode corresponds to the shape of the transfer mold.

8. The manufacturing method according to claim 7, wherein, the shape of the electrode corresponding to the tapered hole portion is conical, and the front end diameter of the conical portion of the electrode corresponding to the tapered hole portion is 5 μm or less.

9. The manufacturing method according to any one of claims 1 to 3, wherein, in the grinding step, according to the image obtained by photographing the grinding surface with a camera, it is confirmed whether there is a hole that becomes the discharge port and its aperture.

10. The manufacturing method according to any one of claims 1 to 3, wherein, the through hole is composed of the tapered hole portion and a cylindrical hole portion extending from the tapered hole portion to the injection port.

11. The manufacturing method according to any one of claims 1 to 3, wherein, the aperture of the discharge port is less than 30 μm.

12. The manufacturing method according to any one of claims 1 to 3, wherein, the precision nozzle is a nozzle for electronic parts.

13. The manufacturing method according to any one of claims 1 to 3, wherein, the precision nozzle is a reflow nozzle for melting solder balls and ejecting them.

14. A precision nozzle, formed of a cemented carbide, and having a through hole penetrating from an injection port to a discharge port; The through hole includes a tapered hole portion extending from the ejection port along a direction in which the inner diameter increases toward the injection port; the diameter of the ejection port is less than 45 μm; and the length of the tapered hole portion in the nozzle axis direction is 1 mm or more.

15. The precision nozzle according to claim 14, wherein the length of the tapered hole portion in the nozzle axis direction is 10 times or more the diameter of the ejection port.

16. The precision nozzle according to claim 14 or 15, wherein the shape of the ejection port is circular, and the roundness of the ejection port is 5 μm or less.

17. The precision nozzle according to claim 14 or 15, wherein the outer shape of the precision nozzle of the ejection port is an isotropic shape, the shape of the ejection port is circular, and the concentricity between the outer shape and the ejection port is 10 μm or less.

18. The precision nozzle according to claim 14 or 15, wherein the inclination angle of the tapered hole portion is 3 to 60°.

19. The precision nozzle according to claim 14 or 15, wherein the diameter of the ejection port is less than 30 μm.

20. The precision nozzle according to claim 14 or 15, wherein the diameter of the ejection port is 1 μm or more and less than 30 μm; the length of the tapered hole portion in the nozzle axis direction is 1 to 20 mm; the length of the tapered hole portion in the nozzle axis direction is 100 times or more the diameter of the ejection port; the shape of the ejection port is circular, and the roundness of the ejection port is 5 μm or less; the outer shape of the precision nozzle of the ejection port is circular, and the concentricity between the outer shape and the ejection port is 10 μm or less; and the inclination angle of the tapered hole portion is 4 to 50°.

21. The precision nozzle according to claim 14 or 15, wherein the cemented carbide is an alloy containing tungsten carbide.

Images