Method for manufacturing electronic component and electronic component

Abstract

A method for manufacturing an electronic component includes a pressing step of processing a lead terminal extending from an electric element into a plate shape by sandwiching the lead terminal in a longitudinal direction by using a set of pressing dies, and is characterized in that at least one of the set of pressing dies is subjected to sand blasting on a surface in contact with the lead terminal, and the surface in contact with the lead terminal is subjected to sand blasting on the surface in contact with the lead terminal. Concave and convex parts are randomly formed on the plate surface of the lead terminal.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electronic component and the electronic component. Background Art

[0002] For example, in a surface mounted chip electrolytic capacitor, a lead type electrolytic capacitor is assembled on a base plate, and a pair of plate-shaped lead terminals led out of the electrolytic capacitor are accommodated in a groove of the base plate. The lead terminals are punched into a strip plate shape using a pair of punching dies (see, for example, Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Application Publication No. 2019-16761.

[0006] Patent document 2: Japanese Patent Application Publication No. 2020-194978. Summary of the invention

[0007] Problems to be solved by the invention

[0008] During the stamping process of the lead terminal, for example, the surface film of the lead terminal is plastically deformed and flows by stamping, which may become metal powder and generate burrs. For example, if the burrs are peeled off and attached to the electronic circuit board due to vibration or contact between the hole of the base plate and the lead terminal, it may cause problems such as short circuits.

[0009] Regarding this problem, for example, Patent Documents 1 and 2 disclose a method in which a metal wire is stamped using a stamping die having multiple groove-shaped recesses to produce a lead terminal having multiple protrusions along the axial direction, thereby suppressing the generation of metal powder residue from the surface film of the lead terminal.

[0010] However, according to the above method, metal powder may be generated in a concentrated manner in the concave portion, so it is difficult to suppress the generation of burrs along the concave portion. In addition, this problem is not limited to surface-mounted chip electrolytic capacitors, but also exists in other surface-mounted electronic components having plate-shaped lead terminals.

[0011] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing an electronic component and an electronic component capable of suppressing the generation of burrs of lead terminals.

[0012] Technical solutions to the problem

[0013] The present invention provides a method for manufacturing electronic components, characterized in that it includes a stamping process of using a set of stamping dies to clamp the lead terminals extending from the electrical components along the length direction and process them into a plate shape. On at least one side of the set of stamping dies, the surface in contact with the lead terminals is sandblasted to randomly form bumps and depressions on the plate surface of the lead terminals.

[0014] In the method for manufacturing an electronic component, the lead terminal may include a tin-plated film.

[0015] In the method for manufacturing the electronic component, bismuth may be added to the tin-plated film.

[0016] In the method for manufacturing an electronic component, the arithmetic mean surface roughness of a surface of at least one of the set of press dies that contacts the lead terminal may be 1.0 to 3.5 μm.

[0017] In the method for manufacturing an electronic component, the arithmetic mean surface roughness of a surface in contact with the lead terminal of at least one of the set of press dies may be 1.6 μm.

[0018] In the method for manufacturing the electronic component, at least one of the set of stamping dies may be subjected to the sandblasting treatment on a surface in contact with the lead terminal so that the arithmetic mean surface roughness of the plate surface of the lead terminal becomes 1.1 to 2.0 μm.

[0019] In the method for manufacturing the electronic component, the sandblasting treatment may be performed on the surface in contact with the lead terminal of at least one of the set of stamping dies so that the ten-point average surface roughness of the plate surface of the lead terminal becomes 7.0 to 15.0 μm.

[0020] In the method for manufacturing an electronic component, the electric element may be a capacitor element.

[0021] The present invention provides an electronic component, characterized in that it comprises an electric element and a plate-shaped lead terminal extending from the electric element, wherein concavities and convexities are randomly formed on a plate surface of the lead terminal.

[0022] In the electronic component, the lead terminal may include a tin-plated film.

[0023] In the electronic component, bismuth may be added to the tin-plated film.

[0024] In the electronic component, the plate surface of the lead terminal may have an arithmetic mean surface roughness of 1.1 to 2.0 μm.

[0025] In the electronic component, the plate surface of the lead terminal may have a ten-point average surface roughness of 7.0 to 15.0 μm.

[0026] In the electronic component, the electric element may be a capacitor element.

[0027] Effects of the Invention

[0028] In one aspect, the generation of burrs on the lead terminals of the electronic component can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a side view showing an example of an aluminum electrolytic capacitor.

[0030] Figure 2 It is a perspective view showing an example of a capacitor element.

[0031] Figure 3 This is a flowchart showing an example of a manufacturing process of an aluminum electrolytic capacitor.

[0032] Figure 4 This is a side view showing an example of a process of punching a lead terminal.

[0033] Figure 5 It is a cross-sectional view showing an example of the lead terminal before and after the punching process.

[0034] Figure 6 This is a front view showing an example of how projections and depressions are formed on the lead terminal in the pressing step.

[0035] Figure 7 This is a front view showing an example of a punching process in which a plurality of groove-shaped recessed portions are provided on a punching surface.

[0036] Figure 8 The figures show (a) an image of the stamping surface when the outer mold and the inner mold are not subjected to sandblasting, (b) an image of the surface roughness measurement of the lead terminal, (c) an image of the surface of the lead terminal, and (d) an image of the cross section of the lead terminal.

[0037] Fig. 9 The figures show (a) an image of the stamping surface when the outer mold and the inner mold are subjected to sandblasting treatment with Ra=1.6 (μm), (b) an image of the surface roughness measurement of the lead terminal, (c) an image of the surface of the lead terminal, and (d) an image of the cross-section of the lead terminal.

[0038] Fig.10The figures show (a) an image of the stamping surface when the outer mold and the inner mold are subjected to sandblasting treatment with Ra=3.2 (μm), (b) an image of the surface roughness measurement of the lead terminal, (c) an image of the surface of the lead terminal, and (d) an image of the cross-section of the lead terminal.

[0039] Fig.11 The drawings are diagrams showing images of cross sections of lead terminals when the outer mold and the inner mold are (a) not subjected to sandblasting, (b) subjected to sandblasting with Ra=1.6 (μm), and (c) subjected to sandblasting with Ra=3.2 (μm).

[0040] Fig.12 The figures are other images of the cross section of the lead terminal when the outer mold and the inner mold are (a) not subjected to sandblasting, (b) subjected to sandblasting with Ra=1.6 (μm), and (c) subjected to sandblasting with Ra=3.2 (μm).

[0041] Fig.13 It is a figure which shows an example of the image of the cross section of the lead terminal before and after the masking process. DETAILED DESCRIPTION

[0042] [Implementation Method]

[0043] (Structure of aluminum electrolytic capacitor)

[0044] Figure 1 1 is a side view showing an example of an aluminum electrolytic capacitor 1. Figure 1 On the paper of FIG. 1 , the internal cross section of the aluminum electrolytic capacitor 1 is shown in the right half of the center line L thereof.

[0045] The aluminum electrolytic capacitor 1 is an example of an electronic component. In this example, a conductive polymer hybrid aluminum electrolytic capacitor is particularly used as the aluminum electrolytic capacitor 1, but the invention is not limited thereto. The aluminum electrolytic capacitor 1 is mounted on an electronic circuit board and is used for coupling, decoupling, smoothing, and the like.

[0046] The aluminum electrolytic capacitor 1 includes a capacitor element 10, a case 11, a sealing member 12, a seat plate 13, a pair of terminal portions 14, and lead terminals 110 and 111. Figure 1 Only one terminal portion 14 is shown in the figure, but another terminal portion 14 is provided at a symmetrical position with respect to the center line L.

[0047] Case 11 is made of aluminum and has a cylindrical shape with an upper opening closed. Case 11 covers capacitor element 10 and sealing body 12 and functions as an exterior of aluminum electrolytic capacitor 1. The shape of case 11 is not limited to a cylindrical shape, but may also be a square cylinder shape.

[0048] Sealing body 12 is a substantially circular member formed of an elastic member such as butyl rubber, etc. Sealing body 12 is adjacent to capacitor element 10 and seals the open end of case 11 .

[0049] As described later, capacitor element 10 has a structure in which anode foil, cathode foil, and separator (electrolytic paper) are stacked and wound. A pair of terminal portions 14 extend from the bottom of capacitor element 10 .

[0050] The pair of terminal portions 14 and lead terminals 110 and 111 are rod-shaped components made of aluminum or the like. The pair of terminal portions 14 are respectively joined to the anode foil and the cathode foil by riveting or other joining methods, and function as the anode terminal and the cathode terminal of the aluminum electrolytic capacitor 1. Each terminal portion 14 is respectively inserted into a pair of through holes 120 formed in the sealing body 12. Figure 1 Only one through hole 120 is shown in the figure, and another through hole 120 is provided at a symmetrical position with respect to the center line L.

[0051] Plate-shaped lead terminals 110 and 111 are provided at the front ends of the pair of terminal portions 14. The lead terminals 110 and 111 are bent into an L shape, and the front end side portions thereof extend along the plate surface of the seat plate 13. The portions of the lead terminals 110 and 111 on the terminal portion 14 side are inserted into the through holes 130 of the seat plate 13. The lead terminals 110 and 111 are soldered to the pads on the electronic circuit substrate in the reflow process of the electronic circuit substrate.

[0052] The seat plate 13 is a plate-shaped member formed of resin or the like, and is disposed at the lower portion of the housing 11 and the sealing body 12. The seat plate 13 supports the housing 11 and the sealing body 12 relative to the electronic circuit substrate to be installed. The seat plate 13 is provided with through holes 130 for the lead terminals 110 and 111 and grooves 131 for accommodating the bent front end portions of the lead terminals 110 and 111. The grooves 131 extend from near the center to the outside along the bottom surface of the seat plate 13. The bottom surface of the seat plate 13 serves as the mounting surface of the aluminum electrolytic capacitor 1 relative to the electronic circuit substrate, so that the plate-shaped lead terminals 110 and 111 can be soldered to the pads on the electronic circuit substrate.

[0053] (Structure of capacitor element)

[0054] Figure 2 is a perspective view showing an example of capacitor element 10. Figure 2 In, with Figure 1 The same reference numerals are used for common structures, and description thereof will be omitted. Capacitor element 10 is an example of an electric element, and includes a wound body 100 in which anode foil 101 , cathode foil 102 , and separator (electrolytic paper) 103 are wound.

[0055] A pair of lead terminals 110 and 111 extend below the wound body 100. The lead terminals 110 and 111 are connected to the anode foil 101 and the cathode foil 102, respectively. Figure 2 The lead terminals 110 and 111 are shown in a state before being bent.

[0056] Anode foil 101 and cathode foil 102 are formed of valve metals such as aluminum, tantalum, titanium, and niobium, and alloy foils thereof, as well as vapor-deposited foils. The surface of anode foil 101 is etched in such a way as to increase the electrode area. Furthermore, an extremely thin oxide film is formed on the surface of anode foil 101. Therefore, anode foil 101 is insulated from other components. The oxide film acts as a dielectric, and capacitor element 10 acts as a capacitor.

[0057] On the other hand, the surface of cathode foil 102 is etched, but no oxide film is formed. Alternatively, the surface of cathode foil 102 may be etched. Alternatively, an oxide film may be formed on the surface of cathode foil 102, or an inorganic layer or a carbon layer may be formed.

[0058] The separator 103 is wound while being sandwiched between the anode foil 101 and the cathode foil 102. The separator 103 is made of at least one selected from cellulose, rayon, glass fiber, etc. The separator 103 is impregnated with an electrolyte and a conductive polymer. In addition, when the aluminum electrolytic capacitor 1 is not a conductive polymer hybrid capacitor, no conductive polymer is used.

[0059] In the manufacturing process of the aluminum electrolytic capacitor 1, the lead terminals 110 and 111 are punched from a round bar shape into a plate shape by a punching die. Therefore, the lead terminals 110 and 111 have a flat shape corresponding to surface mounting on an electronic circuit board. In this punching process, the plate surface S of the lead terminals 110 and 111 is randomly formed with projections and depressions by a punching die subjected to sandblasting as described later.

[0060] Reference symbol Ga schematically shows an example of a cross section of the lead terminal 110 along line AA. Concavoconvex 110a is randomly formed on the plate surface S of the lead terminal 110. The concavoconvex 110a on the plate surface S of the lead terminal 110 does not have a directionality like a groove, and the height and direction are random. In addition, reference symbol Gb schematically shows the concavoconvex 110a of the plate surface S of the lead terminal 110 in a plan view. Here, x represents the width direction of the lead terminal 110, and y represents the length direction of the lead terminal 110. A plurality of convex portions 80 and concave portions 81 of random shapes are formed on the plate surface S. The arrangement of the convex portions 80 and the concave portions 81 is irregular, and the convex portions 80 and the concave portions 81 are arranged in a random two-dimensional direction, not in a certain direction. Therefore, a groove along a certain direction is not formed on the plate surface S. The concavoconvex 110a is transferred from the surface of the stamping die subjected to sandblasting to the lead terminal 110 during the stamping process. Although not shown in the figure, similar random irregularities are also formed on the plate surface S of the other lead terminal 111 .

[0061] (Manufacturing process of aluminum electrolytic capacitors)

[0062] Figure 3 1 is a flowchart showing an example of a manufacturing process of the aluminum electrolytic capacitor 1. The manufacturing process of the aluminum electrolytic capacitor 1 is an example of a method for manufacturing an electronic component.

[0063] First, terminal portion 14 is connected to anode foil 101 and cathode foil 102 prepared in advance (step St1). Although riveting is mentioned as a connection method, it is not limited to this.

[0064] Next, the separator 103 , the anode foil 101 , the cathode foil 102 , and the separator 103 are stacked and wound in this order, and the outer surfaces are fixed with a winding fixing tape, thereby manufacturing the wound body 100 (step St2 ).

[0065] Next, a chemical conversion treatment is performed on the wound body 100 (step St3). Thus, the defects of the oxide film formed on the surface of the anode foil 101 are repaired. In the chemical conversion treatment, a conversion solution is used in which a solute having an organic acid salt of a carboxylic acid group or an inorganic acid salt such as phosphoric acid is dissolved in an organic solvent or an inorganic solvent.

[0066] Next, the wound body 100 is immersed in a conductive polymer dispersion containing water and an organic solvent for 20 minutes in a reduced pressure atmosphere, and then the wound body 100 is pulled out from the conductive polymer dispersion (step St4 ). Thus, the wound body 100 can be impregnated with the conductive polymer.

[0067] Next, in a reduced pressure atmosphere, a predetermined amount of electrolyte is impregnated into the winding body 100 (step St5). In addition, the electrolyte may be a liquid in which a solute is mixed in a conductive polymer dispersion. That is, a conductive polymer dispersion can be used as the electrolyte. In this case, the impregnation of the electrolyte and the impregnation of the conductive polymer are performed simultaneously. Thus, the capacitor element 10 is completed. In addition, when a conductive polymer is not used in the capacitor element 10, steps St3 and St4 can be omitted.

[0068] Next, winding body 100 is housed in case 11 and sealed with sealing body 12 (step St6). At this time, terminal portion 14 extending from winding body 100 is inserted into through hole 120 of sealing body 12. Then, aging treatment may be performed while applying rated voltage to capacitor element 10.

[0069] Next, the lead terminals 110 and 111 are sandwiched along the length direction by a set of stamping dies and stamped into a plate shape (step St7). Thus, the cross-sectional shape of the lead terminals 110 and 111 is stamped from a circular shape to a plate shape by the stamping die to correspond to surface mounting on the electronic circuit substrate. In this stamping process, concavities and convexities are randomly formed on the plate surface S of the lead terminals 110 and 111. In addition, the details of the stamping process will be described later.

[0070] Next, the base plate 13 is mounted on the housing 11 (step St8). At this time, the lead terminals 110 and 111 are inserted into the through holes 130 of the base plate 13, cut to an appropriate length, and bent into an L shape. The bent front end portions of the lead terminals 110 and 111 are accommodated in the grooves 131 provided on the bottom surface of the base plate 13. Thus, the aluminum electrolytic capacitor 1 is completed.

[0071] (Pressing process)

[0072] Figure 4 1 is a side view showing an example of a stamping process of the lead terminals 110 and 111. The stamping device 9 has a set of outer dies 90 and 91 and an inner die 92 as stamping dies. The outer dies 90 and 91 and the inner die 92 are, for example, substantially rectangular metal parts, and have a higher hardness than the core of the lead terminals 110 and 111.

[0073] The outer molds 90 and 91 are disposed on opposite sides of the inner mold 92. The aluminum electrolytic capacitor 1 is conveyed by, for example, a conveying arm device, and the lead terminals 110 and 111 are held at positions straddling the inner mold 92. The outer molds 90 and 91 move parallel to the inner mold 92 as indicated by reference numeral d.

[0074] Thus, the lead terminals 110 and 111 are sandwiched along the length direction thereof by the outer dies 90 and 91 and the inner die 92. At this time, the punching surface 920 of the inner die 92 and the punching surface 900 of the outer die 90 are in contact with one lead terminal 110, and the punching surface 921 of the inner die 92 and the punching surface 910 of the outer die 91 are in contact with the other lead terminal 111. The shorter the punching time, the better, for example, 0.01 (second) or less, so that the size of the burr becomes smaller.

[0075] Figure 5 1 is a cross-sectional view showing an example of lead terminals 110 and 111 before and after stamping. Figure 5 Indicates along Figure 2 The cross section of line A-A.

[0076] The lead terminals 110 and 111 have, for example, a three-layer structure. The lead terminals 110 and 111 have a core layer 20, a coating layer 21, and a plating layer 22. The core layer 20 is the core of the wire material of the lead terminals 110 and 111, and is formed of, for example, iron. The coating layer 21 is a coating covering the core layer 20, and is formed of, for example, copper.

[0077] In order to improve the adhesion with solder in the reflow process, the plating layer 22 is formed of tin, for example. The plating layer 22 is an example of a tin-plated film. Here, the plating layer 22 can also be formed by adding bismuth to tin. When bismuth is added, the generation of whiskers (needle-shaped crystals) in the plating layer 22 is suppressed. In addition, the hardness of the plating layer 22 is lower than the hardness of the outer molds 90, 91 and the inner mold 92.

[0078] The lead terminals 110 and 111 have a substantially circular cross-sectional shape before stamping, but have a substantially strip-shaped cross-sectional shape after stamping. The outermost plating layer 22 is plastically deformed by stamping, and burrs are generated in the plating layer 22 due to flow.

[0079] [Table 1]

[0080]

[0081] Table 1 shows the thickness Da to Dc of each layer of the lead terminals 110 and 111 before stamping according to the types of the lead terminals 110 and 111 of No. 1 to 3. The wire diameters r of the lead terminals 110 and 111 of No. 1 to 3 are different from each other. The larger the wire diameter r, the larger the thickness Dc of the core layer 20 and the thickness Db of the coating layer 21. In addition, the thickness Da of the plating layer 22 of No. 1 to 3 is the same as each other.

[0082] [Table 2]

[0083]

[0084] Table 2 above shows the dimensions of the lead terminals 110 and 111 after punching of No. 1 to 3 in Table 1. The larger the wire diameter r, the larger the thickness T and width W of the lead terminals 110 and 111.

[0085] Figure 6 FIG. 1 is a front view showing an example of how the concavo-convex 110a is formed on the lead terminal 110 in the stamping process. Figure 6 In, with Figure 1 and Figure 4 The same reference numerals are used for common structures, and their descriptions are omitted. Figure 6 Local representation Figure 4 As shown in the reference numeral d, the front end of the lead terminal 110 is viewed from the front when the outer mold 90 and the inner mold 92 are sandwiched between the lead terminal 110 (refer to Figure 4 denoted by reference numeral V).

[0086] The stamping surface 920 of the inner mold 92 and the stamping surface 900 of the outer mold 90 are subjected to sandblasting so that they have a predetermined surface roughness in advance. The shape of the medium (abrasive material) used in the sandblasting process may be amorphous and spherical, but is not limited thereto. In addition, as the surface roughness of each stamping surface 900, 920 after sandblasting, Ra (arithmetic mean surface roughness) is set to 1.6. Of course, Ra after sandblasting is not limited thereto, and may be set to 1.0 to 3.5 (μm), and may preferably be set to 1.1 to 2.0 (μm).

[0087] Concavities and convexities are randomly formed on each of the stamping surfaces 900 and 920 by sandblasting. The hardness of the inner mold 92 and the outer mold 90 is higher than the hardness of the plating layer 22, so the concavities and convexities of the stamping surfaces 900 and 920 of the inner mold 92 and the outer mold 90 are actually transferred to the lead terminal 110. Therefore, the lead terminal 110 is pressed by the stamping surfaces 900 and 920 to form a plate surface S having random concavities and convexities 110a. Here, the Ra of the concavities and convexities 110a is 1.1 to 2.0 (μm). In addition, the Rz (ten-point average surface roughness) of the concavities and convexities 110a is 7.0 to 15.0 (μm). In addition, Ra and Rz are specified in "JIS (Japan Industrial Standards) B 0601 (1994)" and "JIS B 0031 (1994)".

[0088] By such a stamping process, the plating layer 22 is plastically deformed and flows toward the end of the plating layer 22, forming burrs P. However, the flow of the plating layer 22 is suppressed by the random unevenness of the stamping surfaces 900 and 920, so the generation of burrs P is suppressed more than when the stamping surfaces 900 and 920 are not subjected to sandblasting. In addition, in this example, one lead terminal 110 is used as an example, but the other lead terminal 111 is also the same as above, and the generation of burrs P can be suppressed. In addition, in this example, the unevenness formed by sandblasting is provided on the stamping surfaces 900, 910, and 920 of both the outer mold 90, 91 and the inner mold 92, but the unevenness may be provided only on the stamping surface 900, 910, and 920 of one of the outer mold 90, 91 and the inner mold 92.

[0089] Unlike the present embodiment, if a plurality of groove-shaped recessed portions are provided on the press surfaces 900 , 910 , and 920 as in the above-mentioned Patent Document 1, there is a possibility that burrs may increase as described below.

[0090] Figure 7 1 is a front view showing an example of a stamping process in which a plurality of groove-shaped recessed portions 900a and 920a are provided on the stamping surfaces 900 and 920. Figure 7 In, with Figure 1 and Figure 4 The same reference numerals are used for common structures, and their descriptions are omitted. Figure 7 Local representation Figure 4 As shown in the reference numeral d, the front end of the lead terminal 110 is viewed from the front when the outer mold 90 and the inner mold 92 are sandwiched between the lead terminal 110 (refer to Figure 4 denoted by reference numeral V).

[0091] A plurality of groove-shaped recessed portions 900 a and 920 a are provided on the punching surfaces 900 and 920 . The recessed portions 900 a and 920 a extend in the longitudinal direction of the lead terminal 110 .

[0092] The lead terminal 110 is pressed by the punching surfaces 900 and 920, and the metal powder of the plating layer 22 may flow into the recesses 900a and 920a. Therefore, unlike the present embodiment, not only convex stripes but also a plurality of burrs Q may be generated along the recesses 900a and 920a on the plate surface S of the lead terminal 110.

[0093] Example

[0094] Next, an embodiment of a method for manufacturing an aluminum electrolytic capacitor 1 is described. In this example, after sandblasting is performed on each stamping surface 900, 910, 920 of the outer mold 90, 91 and the inner mold 92 so that Ra becomes 1.6 (μm) or 3.2 (μm), the stamping process is performed. In addition, for comparison, a stamping process is also performed by the outer mold 90, 91 and the inner mold 92 that have not been sandblasted. At this time, the Ra of each stamping surface 900, 910, 920 is set to be less than 0.5 (μm). In addition, as a medium for sandblasting, a spherical medium corresponding to the target Ra is used. In addition, the thickness Da~Dc of each layer of the lead terminal 110, 111 is as described in Table 1.

[0095] [Table 3]

[0096]

[0097] Table 3 shows Ra and Rz of a plurality of samples of the lead terminals 110 and 111 after the press process and their averages when the outer molds 90 and 91 and the inner mold 92 were not subjected to sandblasting, when the sandblasting was performed at Ra=1.6 (μm), and when the sandblasting was performed at Ra=3.2 (μm). When the sandblasting was not performed, the Ra of the plate surface S of the samples No. 1 to No. 5 of the five lead terminals 110 and 111 was measured. When the sandblasting was performed at Ra=1.6 (μm) and Ra=3.2 (μm), the Ra and Rz of the plate surface S of the samples No. 1 to No. 10 of the ten lead terminals 110 and 111 were measured, respectively.

[0098] In the case of samples No. 1 to No. 5 without sandblasting, lead terminals 110 and 111 with bismuth added to the plating layer 22 are No. 4 and 5, and lead terminals 110 and 111 with no bismuth added to the plating layer 22 are No. 1, 2, and 3. In the case of samples No. 1 to No. 10 with sandblasting of Ra = 1.6 (μm), lead terminals 110 and 111 with bismuth added to the plating layer 22 are No. 4, 5, 6, 9, and 10, and lead terminals 110 and 111 with no bismuth added to the plating layer 22 are No. 1, 2, 3, 7, and 8. Among samples No. 1 to No. 10 subjected to the sandblasting treatment with Ra=3.2 (μm), lead terminals 110 and 111 having bismuth added to plating layer 22 are Nos. 4, 5, 6, 9, and 10, and lead terminals 110 and 111 having no bismuth added to plating layer 22 are Nos. 1, 2, 3, 7, and 8.

[0099] Figure 8The figures show (a) images of the stamping surfaces 900, 910, 920, (b) images of the surface roughness of the lead terminals 110, 111, (c) images of the surfaces of the lead terminals 110, 111, and (d) images of the cross sections of the lead terminals 110, 111 when the sandblasting treatment is not performed on the outer molds 90, 91 and the inner mold 92. In the image of the cross section of the lead terminals 110, 111 (d), the dotted lines indicate the boundaries of the plating layer 22, the cladding layer 21, and the core layer 20. The images were taken using a laser microscope.

[0100] When the sandblasting process is not performed, the surface irregularities of the stamping surfaces 900, 910, 920 and the lead terminals 110, 111 are small. In addition, in the stamping process, almost no flow occurs in the center of the plating layer 22, and its thickness is 8 (μm), but large flow occurs at both ends of the plating layer 22 (see the circle), and its thickness becomes half of 3 to 4 (μm). Due to this flow, burrs are generated at the ends of the lead terminals 110, 111.

[0101] Fig. 9 The figures show (a) images of the stamping surfaces 900, 910, 920, (b) images of the surface roughness of the lead terminals 110, 111, (c) images of the surfaces of the lead terminals 110, 111, and (d) images of the cross sections of the lead terminals 110, 111 when the sandblasting treatment of Ra=1.6 (μm) is performed on the outer molds 90, 91 and the inner mold 92. In the image of the cross section of the lead terminals 110, 111 (d), the dotted lines indicate the boundaries of the plating layer 22, the cladding layer 21, and the core layer 20. The images were taken using a laser microscope.

[0102] When the sandblasting treatment with Ra=1.6 (μm) is performed, the surfaces of the stamping surfaces 900, 910, 920 and the lead terminals 110, 111 are formed with irregularities with random heights and directions, which do not have the directionality of the grooves. Due to the random irregularities of the stamping surfaces 900, 910, 920, the degree of flow of the surface of the plating layer 22 is averaged as a whole, and its thickness is 8 to 12 (μm) as a whole. Therefore, the generation of burrs is further suppressed than when the sandblasting treatment is not performed.

[0103] Fig.10The figures show (a) images of the stamping surfaces 900, 910, 920, (b) images of the surface roughness of the lead terminals 110, 111, (c) images of the surfaces of the lead terminals 110, 111, and (d) images of the cross sections of the lead terminals 110, 111 when the sandblasting treatment of Ra=3.2 (μm) is performed on the outer molds 90, 91 and the inner mold 92. In the image of the cross section of the lead terminals 110, 111 (d), the dotted lines indicate the boundaries of the plating layer 22, the cladding layer 21, and the core layer 20. The images were taken using a laser microscope.

[0104] When the sandblasting treatment of Ra=3.2 (μm) is performed, the surfaces of the stamping surfaces 900, 910, 920 and the lead terminals 110, 111 are formed with random height and direction irregularities without directionality like grooves. The size of the irregularities is larger than that of the case where the sandblasting treatment of Ra=1.6 (μm) is performed. Due to the random irregularities of the stamping surfaces 900, 910, 920, the degree of flow of the metal powder is averaged on the surface of the plating layer 22, and its thickness becomes 2 to 20 (μm) as a whole. Therefore, the generation of burrs is more suppressed than when the sandblasting treatment is not performed, but the unevenness of the thickness is larger than that of the case where the sandblasting treatment of Ra=1.6 (μm) is performed, and therefore, the exposed portion of the coating layer 21 on the inner side of the plating layer 22 is observed (see the circle).

[0105] Fig.11 The diagrams show cross-sectional images of the lead terminals 110 and 111 in the case where (a) the outer molds 90 and 91 and the inner mold 92 are not subjected to sandblasting, (b) the case where the sandblasting is performed with Ra=1.6 (μm), and (c) the case where the sandblasting is performed with Ra=3.2 (μm). Each cross section is taken along Figure 2 The cross section of the line AA of FIG. 2 is shown in FIG. 2 . The composition of the plating layer 22 is set to 100 (%) tin.

[0106] The circles represent the burrs produced during the stamping process. Fig.11 It can be understood that the burrs are largest when the sandblasting is not performed, and the burrs are smallest when the sandblasting is performed with Ra=3.2 (μm).

[0107] Fig.12 The figure is another image showing the cross-section of the lead terminals 110 and 111 in the case where (a) the outer mold 90 and 91 and the inner mold 92 are not subjected to sandblasting, (b) the case where the sandblasting is performed with Ra=1.6 (μm), and (c) the case where the sandblasting is performed with Ra=3.2 (μm). Each cross section is taken along Figure 2 The cross section of the line AA of FIG. 1 is shown. The image was taken using a laser microscope. In this example, the composition of the plating layer 22 is 99.5 (%) tin and 0.5 (%) bismuth.

[0108] The dotted circle represents the burrs produced during the stamping process. Fig.12 It can be understood that the burrs are generated by the metal powder of the plating layer 22 on both ends of the lead terminals 110 and 111 flowing outward and extending outward along the plate surface of the lead terminals 110 and 111. The burrs are the largest when the sandblasting is not performed, and the burrs are the smallest when the sandblasting is performed with Ra=3.2 (μm). The size of the burrs is quantitatively measured by masking the above-mentioned image.

[0109] Fig.13 The figure shows an example of the image of the cross section of the lead terminals 110 and 111 before and after the masking process. The total number of pixels was measured after the image was masked, except for the burr regions at the four corners of the lead terminals 110 and 111.

[0110] [Table 4]

[0111]

[0112] Table 4 shows the total number of pixels in the burr region. The number of pixels was measured for lead terminals 110 and 111 containing no bismuth and lead terminals 110 and 111 containing 0.5 (%) bismuth. In addition, the measurement was performed when the outer mold 90, 91 and the inner mold 92 were not subjected to sandblasting, when the sandblasting was performed with Ra = 1.6 (μm), and when the sandblasting was performed with Ra = 3.2 (μm). In addition, the measurement results are shown as the average value of the samples of lead terminals 110 and 111 shown in Table 3.

[0113] Regardless of whether bismuth is contained or not, when the sandblasting treatment is performed on the outer mold 90, 91 and the inner mold 92, the number of pixels is reduced compared to the case where the sandblasting treatment is not performed. When the sandblasting treatment with Ra = 1.6 (μm) is performed, the number of pixels in the burr area of ​​the lead terminals 110, 111 whose plating layer 22 does not contain bismuth is reduced by about 40 (%), and the number of pixels in the burr area of ​​the lead terminals 110, 111 whose plating layer 22 contains bismuth is reduced by about 45 (%). In addition, when the sandblasting treatment with Ra = 3.2 (μm) is performed, the number of pixels in the burr area of ​​the lead terminals 110, 111 whose plating layer 22 does not contain bismuth is reduced by about 56 (%), and the number of pixels in the burr area of ​​the lead terminals 110, 111 whose plating layer 22 contains bismuth is reduced by about 47 (%).

[0114] In addition, when the sandblasting process with Ra=3.2 (μm) is performed, the number of pixels is reduced compared with the case of the sandblasting process with Ra=1.6 (μm). This is because, as described above, when the sandblasting process with Ra=3.2 (μm) is performed, the surface roughness of the lead terminals 110 and 111 is further increased.

[0115] Regardless of whether the sandblasting process is performed or not, the number of pixels in the burr region of the lead terminals 110 and 111 whose plating layer 22 contains bismuth is smaller than the number of pixels in the burr region of the lead terminals 110 and 111 whose plating layer 22 does not contain bismuth. This is because the inclusion of bismuth increases the hardness of the tin plating and makes the plating itself less likely to flow.

[0116] In addition, when the number of pixels in the burr region of the lead terminals 110 and 111 whose plating layer 22 contains bismuth is compared with the lead terminals 110 and 111 whose plating layer 22 does not contain bismuth, the difference between the cases where Ra of the sandblasting treatment is 1.6 (μm) and 3.2 (μm) is small. This is because the hardness of the tin plating layer is increased by the inclusion of bismuth, and the force during punching is more easily transmitted to the core layer 20.

[0117] Thus, in the stamping process, the lead terminals 110 and 111 are sandwiched by the outer molds 90 and 91 and the inner mold 92 whose stamping surfaces 900, 910 and 920 are subjected to sandblasting, and the plate surface S thereof is randomly formed with irregularities, thereby suppressing the generation of burrs. At this time, when the stamping surfaces 900, 910 and 920 are subjected to sandblasting so that Ra becomes 3.2 (μm), as shown in FIG. Fig.10 As shown in the image (d), the coating layer 21 may be exposed.

[0118] Therefore, it is preferable to perform sandblasting on the stamping surfaces 900, 910, and 920 so that Ra becomes 1.6 (μm). Therefore, based on the Ra and Rz of the lead terminals 110 and 111 shown in Table 3, it is preferable to perform sandblasting on the stamping surfaces 900, 910, and 920 so that Ra of the plate surface S becomes 1.1 to 2.0 (μm) or Rz of the plate surface S becomes 7.0 to 15.0 (μm). This prevents the inner coating layer 21 from being exposed due to the fall of the plating layer 22.

[0119] In addition, the size of burrs of the lead terminals 110 and 111 and the presence or absence of exposure of the coating layer 21 were evaluated when the pressing process was performed using various media for sandblasting.

[0120] [Table 5]

[0121]

[0122] Table 5 shows the evaluation results of the size of the burrs of the lead terminals 110 and 111 for each medium subjected to sandblasting and the presence or absence of the coating layer 21 being exposed. As the medium, an amorphous medium corresponding to Ra=1.6 (μm), an amorphous medium corresponding to Ra=3.2 (μm), a spherical medium corresponding to Ra=3.2 (μm), and a spherical medium corresponding to Ra=1.6 (μm) were used. In addition, for comparison, the lead terminals 110 and 111 without sandblasting were also evaluated (see "N / A"). In any case, 10 lead terminals 110 and 111 were used as samples and evaluated.

[0123] Table 5 shows the measurement results of Ra of the outer mold 90, 91 and the inner mold 92 (stamping mold) for each medium, Ra of the lead terminals 110, 111 to which bismuth is not added to the plating layer 22, and Ra of the lead terminals 110, 111 to which bismuth is added to the plating layer 22. In addition, as in the above, the bismuth content is set to 0.5 (%).

[0124] Regardless of the medium used, the size of the burr was smaller than that of the case where the sandblasting was not performed. In addition, when the amorphous medium and spherical medium corresponding to Ra = 1.6 (μm) were used, the exposure of the coating layer 21 was not confirmed, but when the amorphous medium and spherical medium corresponding to Ra = 3.2 (μm) were used, the exposure of the coating layer 21 was confirmed. In this case, the Ra of the outer mold 90, 91 and the inner mold 92 (stamping mold) became larger than that of the case where the amorphous medium and spherical medium with Ra = 1.6 (μm) were used, so the plating layer 22 was cut deeper.

[0125] Therefore, by using an amorphous medium or a spherical medium corresponding to Ra=1.6 (μm), exposure of the coating layer 21 is suppressed.

[0126] In this example, evaluation was performed using the lead terminals 110 and 111 having the plating layer 22 having a thickness of 9 to 15 μm, but the present invention is not limited thereto. The Ra of the sandblasting treatment is preferably appropriately set according to the thickness of the plating layer 22 .

[0127] As described so far, according to the above-mentioned aluminum electrolytic capacitor 1 and its manufacturing method, the burrs generated on the lead terminals 110 and 111 can be suppressed, but the same method can also be applied to other electronic components having plate-shaped lead terminals. Of course, in the case of capacitors such as the aluminum electrolytic capacitor 1, the greater the electrostatic capacitance, the higher the risk of a short circuit accident caused by the burrs when the burrs are peeled off from the lead terminals 110 and 111. Therefore, it is particularly useful to apply the above-mentioned method to capacitors with large capacitance such as the aluminum electrolytic capacitor 1 among electronic components.

[0128] As mentioned above, although the embodiment of the present invention is described in detail, the present invention is not limited to the above-mentioned specific embodiment, and various deformation|transformation and changes can be made within the scope of the summary of the present invention described in the claims.

[0129] Description of Reference Numerals

[0130] 1Aluminum electrolytic capacitor

[0131] 10Capacitor elements

[0132] 11 Shell

[0133] 12 Sealing body

[0134] 13 Seat Plate

[0135] 22 coating

[0136] 90, 91 external model

[0137] 92 inner mold

[0138] 110, 111 lead terminals

[0139] P, Q burrs.

Claims

1. A method for manufacturing an electronic component, characterized in that: The method comprises a stamping process of using a set of stamping dies to clamp the lead terminals extending from the electrical components along the length direction and process them into a plate shape. At least one of the set of punching dies is subjected to sandblasting on a surface in contact with the lead terminal so that irregularities are randomly formed on a plate surface of the lead terminal.

2. The method for manufacturing an electronic component according to claim 1, wherein: The lead terminal has a tin-plated film.

3. The method for manufacturing an electronic component according to claim 2, wherein: Bismuth is added to the tin-plated film.

4. The method for manufacturing an electronic component according to claim 2 or 3, characterized in that: At least one of the set of punching dies has an arithmetic mean surface roughness of 1.0 to 3.5 μm on a surface in contact with the lead terminal.

5. The method for manufacturing an electronic component according to claim 2 or 3, characterized in that: At least one of the set of punching dies has an arithmetic mean surface roughness of 1.6 μm on a surface in contact with the lead terminal.

6. The method for manufacturing an electronic component according to claim 5, wherein: At least one of the set of punching dies has a surface in contact with the lead terminal subjected to the sandblasting treatment so that the arithmetic mean surface roughness of the plate surface of the lead terminal is 1.1 to 2.0 μm.

7. The method for manufacturing an electronic component according to claim 5, wherein: At least one of the set of punching dies has a surface in contact with the lead terminal subjected to the sandblasting treatment so that a ten-point average surface roughness of a plate surface of the lead terminal is 7.0 to 15.0 μm.

8. The method for manufacturing an electronic component according to any one of claims 1 to 3, characterized in that: The electrical element is a capacitor element.

9. An electronic component, characterized in that: have: Electrical components; and a plate-shaped lead terminal extending from the electrical component, Concavities and convexities are randomly formed on the plate surface of the lead terminal.

10. The electronic component according to claim 9, characterized in that The lead terminal has a tin-plated film.

11. The electronic component according to claim 10, characterized in that Bismuth is added to the tin-plated film.

12. The electronic component according to any one of claims 9 to 11, characterized in that: The plate surface of the lead terminal has an arithmetic mean surface roughness of 1.1 to 2.0 μm.

13. The electronic component according to any one of claims 9 to 11, characterized in that: The ten-point average surface roughness of the plate surface of the lead terminal is 7.0 to 15.0 μm.

14. The electronic component according to any one of claims 9 to 11, characterized in that: The electrical element is a capacitor element.

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