JP2006080146A - Manufacturing method of resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain highly the joint position accuracy of the piece 2 of a resistor and the piece 1 of an electrode at the time of manufacturing the resistor where a pair of electrode pieces 1 are constitutively jointed at the end opposite to the piece 2 of the resistor. <P>SOLUTION: After jointing the single piece 1 of an electrode and the piece 2 of a resistor, the manufacturing method comprises a process for cutting or removing the portion of the piece 1 of the electrode opposite to the side of the piece 2 of the resistor other than the end opposite to the piece 2 of the resistor. It is preferred to have a gap between the side of the piece 2 of the resistor other than the end opposite to the piece 2 of the resistor and the opposite side of the piece 1 of the electrode. Further, it is preferred that formation of the gap may be realized in an electrode piece shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a low resistor or the like mainly used for current detection using a metal plate for both a resistor and an electrode, for example.

Japanese Unexamined Utility Model Publication No. 6-262201 discloses a method of manufacturing a resistor having a step of joining both opposing end portions of a plate-like resistor and a pair of electrodes made of a plate-like copper-based material. There is that disclosure.
Japanese Utility Model Publication No.6-26261

  In the above bonding, it may be difficult to match the bonding positions of the pair of electrodes. In particular, when the electrode is bent into a chip shape (for example, FIGS. 1 (f) to (h)), a long electrode length is often used. (End of the electrode piece farthest from the resistor piece) This greatly affects the displacement. The slight deviation is extremely difficult to correct after joining, and must be eliminated before joining. However, the handleability of each of the resistor piece and the electrode piece is not good before joining. In particular, when the thickness of the resistor piece and the electrode piece is thin, the handleability is extremely poor, and it is very difficult to eliminate the slight deviation.

  Therefore, the problem to be solved by the present invention is to maintain a high accuracy of the bonding position between the resistor piece and the electrode piece.

  In order to solve the above-described problem, a method of manufacturing a resistor in which a pair of electrode pieces 1 are joined to opposite ends of a resistor piece 2 of the present invention includes a single electrode piece 1 and a resistor piece 2. After joining, it has the process of cut | disconnecting or removing the electrode piece 1 part which opposes the resistor piece 2 surfaces other than the edge part which the said resistor piece 2 opposes (for example, FIG. 1).

  Here, the “electrode piece 1” is, for example, a material mainly composed of copper. The material mainly composed of copper is pure copper or an alloy mainly composed of copper. These have a sufficiently low specific resistance even when used as an electrode material for a low resistor for current detection, for example, and are suitable as electrode materials.

  In addition, as the “resistor piece 2”, a Ni—Cr alloy, a Ni—Cr—Al alloy, a Cu—Ni alloy, a Cu—Mn—Sn alloy, or the like can be suitably used.

  Further, the “cutting” is to cut off the electrical connection of the electrode piece 1 portion facing the surface of the resistor piece 2 other than the opposing end of the resistor piece 2 (for example, FIG. 1D and ( e)). For example, there are means for mechanically cutting using a scissors, a dicing saw or the like, and means for cutting by thermal melting by laser irradiation or the like. Further, the “removal” is to remove the electrode piece 1 so as to cut off the electrical connection of the electrode piece 1 portion facing the surface of the resistor piece 2 other than the opposing end of the resistor piece 2. For example, there are means for cutting two or more portions of the electrode piece 1 (FIG. 1 (d)), means for scraping with a grinder, chemical removal means such as etching, and the like.

  Here, it is preferable to have a gap as shown in FIG. 1 between the surface of the resistor piece 2 other than the opposing end of the resistor piece 2 and the surface of the electrode piece 1 facing the surface. This is because cutting and removal work becomes easy. Further, this is for preventing damage to the resistor piece 2 due to handling during cutting or removing work. Further, the formation of the gap is preferably realized by an electrode piece shape (FIGS. 1A to 1D). As described above, the portion of the electrode piece 1 facing the resistor piece 2 is cut or removed, so that even if the shape of the electrode piece 1 is freely deformed to some extent, the characteristics of the resistor are less affected. Reference numeral 2 denotes a member for determining the resistance value of the resistor, for reasons such as undesirable deformation. For example, as shown in FIG. 1, the gap can be formed by bending the electrode piece 1 facing the resistor piece 2 so as to be convex.

  The “single electrode piece 1” is a member constituting the so-called single plate, as shown in FIG. 1, in which the “pair of electrode pieces 1” is integrally joined. As described above, after joining the single electrode piece 1 and the resistor piece 2, the electrode piece 1 surface facing the resistor piece 2 surface other than the opposing end of the resistor piece 2 is cut or removed. By doing so, the single electrode piece 1 is separated into a pair of electrode pieces 1. As a result, each of the pair of electrode pieces 1 is indirectly electrically connected via the resistor piece 2 without being directly electrically connected. Thus, the resistor according to the present invention is configured by joining the pair of electrodes at the opposite ends of the resistor piece 2.

  By passing through the resistor manufacturing process in this order, the bonding position accuracy between the resistor piece 2 and the electrode piece 1 can be maintained high. The reason will be explained. Since the initial pair of electrode pieces 1 according to the present invention is integrated, the positional relationship between the electrode pieces 1 is fixed. Therefore, the joining position alignment at the time of joining with the resistor piece 2 is easy, and as a result, the joining position accuracy between the resistor piece 2 and the electrode piece 1 can be maintained high. Conventionally, it has been difficult to fix the positional relationship between the pair of electrode pieces 1 and the resistor pieces 2. This is because each piece-like member has to be handled individually.

  After the joining, and before or after the cutting or removing step, the electrode piece 1 and / or the resistor piece 2 may be subjected to a step of cutting so as to have a necessary size for the unit resistor. it can. In this case, even if the situation that the joining position alignment at the time of joining of the electrode piece 1 and the resistor piece 2 is shifted occurs, the entire shape of the resistor according to the present invention can be adjusted by the cutting step. This is preferable in that it is possible to eliminate problems caused by the “deviation”. The defect is, for example, the electrode end position shift described above.

  The joining is preferably performed by seam welding. The first reason will be described. Resistors for the purpose of flowing a large current, such as a low resistance for current detection, especially when the electrodes of the resistor and the resistor are locally welded, as in the case of spot welding In this case, a large current flows mainly in the local part, and Joule heat is concentrated. For this reason, the amount of heat generated in the local area becomes excessive, which may adversely affect the temperature characteristics (TCR, etc.) of the resistor. However, in contrast to the spot welding technique, in the seam welding technique, the weld area is larger than that in the spot welding technique, so the phenomenon of the Joule heat concentration hardly occurs. From the same point of view, by performing spot welding at a plurality of locations, the joining area between the electrode piece 1 and the resistor piece 2 can be enlarged to reduce the heat generation amount. Seam welding is advantageous in terms of shortening the manufacturing time because it performs such a plurality of spot weldings continuously.

  The second reason that the joining is preferably performed by seam welding is that a plurality of welding marks 7 can be easily formed at the joining portion between the resistor piece 2 having the unit resistor size and the electrode piece 1, and the resistor piece 2 This is because the effect of maintaining the accuracy of the bonding position between the electrode piece 1 and the electrode piece 1 can be expected. That is, when there is only one welding spot, particularly when the welding mark 7 is circular, the resistance piece 2 and the electrode piece 1 may rotate around the welding mark 7 as a center (fulcrum). In some cases, there is an advantage that this case can be easily eliminated.

  In the seam welding, as shown in FIG. 2, it is preferable that the weld mark 7 once formed and the newly welded region do not overlap each other. The reason is that, since the specific resistance value of the weld mark 7 once formed becomes small, a newly applied welding current mainly flows through the weld mark 7 and it is difficult to form a new weld region.

  According to the present invention, when manufacturing a resistor in which a pair of electrode pieces are bonded to opposite ends of the resistor piece, the bonding position accuracy between the resistor piece and the electrode piece can be maintained high.

(An example of manufacturing a resistor according to the present invention)
A plate (electrode piece 1) having a thickness of 0.3 mm made of pure copper having electrolytic plating of tin (plating thickness of 3 to 7 μm) on the surface, and a Ni—Cr alloy plate (resistor piece 2) having a thickness of 0.2 mm. Prepare. These can use a commercially available thing. Then, the electrode piece 1 is formed by press working so that the end of the plate of the resistor piece 2 and the end of the plate of the electrode piece 1 can overlap each other by about 1 mm. ) To (d).

  Next, the resistor piece 2 is arranged on the surface of the electrode piece 1 so as to close the dent with the resistor piece 2 (FIG. 1B). As described above, the end of the plate of the resistor piece 2 and the end of the plate of the electrode piece 1 were aligned so as to overlap each other by about 1 mm. In such alignment, the positional relationship between the pair of electrode pieces 1 is fixed. Therefore, alignment with the resistor piece 2 was easy. Therefore, the positional accuracy between the resistor piece 2 and the electrode piece 1 can be maintained high.

  Next, the overlapping portions are joined by seam welding (FIG. 1 (c)). The welding apparatus shown in FIG. 3 was used. By rolling a welding current between the plate electrode for welding 5 and the welding disk electrode 4 while rolling the disk electrode for welding 4 (made of molybdenum) along the overlapping portion, the plate of the resistor piece 2 And the end of the plate of the electrode piece 1 are linearly welded. As described above, since the positional accuracy between the resistor piece 2 and the electrode piece 1 before bonding can be maintained high, the positional accuracy can be maintained high even after bonding.

  Here, the welding disk-shaped electrode 4 is made of molybdenum, the welding flat electrode 5 is made of chrome copper, and the welding disk-shaped electrode 4 is harder than the welding flat electrode 5 because of the welding disk-shaped electrode 4. This is because the electrode 4 is a movable member and is pressed against the electrode piece 1 with a small area, so that wear is suppressed. Further, the welding disk-shaped electrode 4 in contact with the electrode piece 1 is made of molybdenum, the welding flat electrode 5 in contact with the resistor piece 2 is made of chrome copper, and the welding disk-shaped electrode 4 is made more than the flat plate electrode 5 for welding. The reason why the specific resistance value is lowered is that no portion having an extremely high resistance value is provided in a portion other than the contact portion between the electrode piece 1 and the resistor piece 2 when a welding current is passed. In other words, this is to prevent welding electrode and electrode piece 1 or resistor piece 2 from being welded by actively generating Joule heat at a location where the resistance value is high.

  Specific welding conditions will be described. The diameter of the welding disk-shaped electrode 4 is 80 mm. The width of the side surface of the welding disk-shaped electrode 4 (the portion in contact with the electrode piece 1 made of a copper plate) is 2 mm. The force which presses the part which the board | plate of the electrode piece 1 and the board | plate of the resistor piece 2 overlap with the disk-shaped electrode 4 for welding and the flat electrode 5 for welding is about 15 kg. The speed at which the welding disk electrode 4 rolls is 1000 mm / min. The welding current passed between the welding flat electrode 5 and the welding disk electrode 4 is a rectangular pulse wave. The pulse width is 15 mm seconds, and the pulse height is a maximum of 2 to 3 kA. As a result, the shape of the unit welding mark 7 was approximately circular or approximately oval as shown in FIG. 2, and the size thereof was about 1 mm in the maximum diameter. At the time of welding, as described above and as shown in FIG. 2, attention was paid so that the weld mark 7 once formed and the newly welded region do not overlap.

  After performing such a seam welding process on each of the opposing opposite ends of the resistor 2, only the electrode piece 1 in the entire area near the opening of the recess is cut with a dicing saw in order to remove the recessed portion of the electrode piece 1. (FIG. 1 (d)). As a result, the recessed portion was removed, and a pair of substantially plate-like electrode pieces 1 were joined to the opposing ends of the resistor piece 2 (FIG. 1 (e)).

  FIG. 2A shows the above state as a plan view. The electrode piece 1 is connected to the resistor piece 2 to the electrode piece 1 by bonding. In order to make this the size required for the unit resistor, it is cut into a piece-like member 8 (FIG. 2B).

  Next, a trimming step is performed to make the resistance value measured between the electrode pieces 1 of the piece-like member 8 within a predetermined range (not shown). In this trimming step, while measuring the resistance value between the electrode pieces 1, the end of the resistor piece 2 is cut off with a grinder having a blade thickness of about 0.1 to 0.85 mm until the resistance value reaches a predetermined value. To form grooves. Moreover, it can replace with a grinder or can employ | adopt the punching by a press with the excision by a grinder.

  Then, the resistor piece 2 and the welded portion (weld mark 7) are molded with a liquid crystal polymer as the mold resin 9 (FIG. 1 (f)). As a result, only one piece of the electrode piece is exposed, and the piece-like member 8 is coated with a resin at the center. Thereafter, one part of the electrode piece is bent along the mold resin 9 (FIGS. 1G and 1H) to complete the surface-mounted resistor according to the present invention. Here, the welding trace 7 is protected by the mold resin 9 in order to eliminate as much as possible any adverse effects on the resistor characteristics due to the bending stress applied to the electrical connection portion such as the welding trace 7. No stress is applied. It goes without saying that a material other than the liquid crystal polymer can be selected as the mold resin material. A thermoplastic resin, a thermosetting resin, etc. can be selected. The advantage of using the liquid crystal polymer is that the resistor is for current detection and the like, and is suitable for dissipating a large amount of heat generated in the resistor piece 2 portion when a large current is assumed to flow.

  In this embodiment, the electrode piece 1 is made of pure copper whose surface is coated with tin. The first reason is to improve weldability. If the tin layer is not provided, even if a welding current is passed through a material mainly composed of copper having a low specific resistance value, the Joule heat is hardly generated, so that the welding state may vary. Therefore, by providing a tin layer having a specific resistance higher than that of pure copper on the surface of the electrode piece 1, heat generation (Joule heat) during welding can be promoted, and a substantially constant welding state can be obtained.

  The second reason that the surface of the electrode piece 1 is coated with tin is to simplify the process of imparting solder wettability to the electrode piece 1. Conventionally, it is complicated to form tin or a solder film on the electrode piece 1 by barrel plating or the like for imparting solder wettability to the exposed electrode piece 1 which has been provided after the manufacture of the resistor with a chip resistor or the like. It took a process. When the resistor is used for surface mounting, it is necessary to realize the adhesion between the cream solder disposed on the land on the mounting substrate surface and the electrode piece 1 of the resistor in a reflow process. The solder wettability imparting step is substantially essential. However, there is an advantage that the barrel plating step can be omitted by using the electrode piece 1 which is pre-coated with tin.

  Here, when the tin or solder film is formed on the surface of the electrode piece 1 of each chip resistor by the barrel plating method, not only the tin 3 or the solder film thickness in each electronic component is likely to vary, but also most of the energized electricity There is a disadvantage in terms of energy cost that the amount is not used for plating. In that respect, for example, it is advantageous to use a tin or solder-coated copper plate in which tin or solder plating is applied to the surface of the copper plate in advance by a normal electrolytic plating method other than the barrel plating method because there is no disadvantage in the barrel plating method. is there. Here, unlike the state of individual resistors, the copper plate does not handle fine workpieces. Therefore, even if it is not based on the barrel plating method, a copper plate is arranged between the electrodes for electrolytic plating in a normal plating bath so as not to come into contact with the electrodes, and electricity is passed between the electrodes for both plating. It is possible to use an electrolytic plating method that is high and requires only a short total time for the plating process.

  In the barrel plating method, individual resistors and dummy balls collide with each other. Then, the exposed electrode piece 1 may be impacted and deformed. Such deformation is not substantially different from the displacement of the electrode piece 1 resulting from the low accuracy of the bonding position between the resistor piece 2 and the electrode piece 1, and therefore the bonding between the resistor piece 2 and the electrode piece 1 according to the present invention. It can be a waste of maintaining high positional accuracy. Therefore, the advantage that the barrel plating process can be omitted is great from this viewpoint.

  Moreover, in this embodiment, it cut | disconnected with the dicing saw for the excision of the recessed part of the electrode piece 1. FIG. However, another method, for example, after inserting a base in the said recessed part and preventing damage to the resistor piece 2, you may cut out the said recessed part by punching the said recessed part with a press. Such punching is advantageous in that there is no generation of chips that cannot be avoided by dicing.

  Further, in the present embodiment, the gap between the resistor piece 2 surface other than the opposing end portion of the resistor piece 2 and the opposing electrode piece 1 surface is shaped as shown in FIGS. It is needless to say that other shapes may be used. For example, a pair of small dents are formed in the electrode piece 1 region in the vicinity of the junction with both the resistor pieces 2, and the electrode piece 1 between the pair of dents is in contact with the resistor piece 2. When the dent is large, the electrode piece 1 is easily bent in the direction of closing the opening of the dent due to the presence of the dent. Therefore, the junction position between the resistor piece 2 and the electrode piece 1 by reducing the dent. There is an advantage that an adverse effect on accuracy can be suppressed. Moreover, the shape of the said dent can be made into the shape where a cross section (surface corresponding to the side surface of FIG. 1) has roundness. There is an advantage that wear of the press mold when forming the dent by press molding can be suppressed, and the mold can be made long-lasting.

  The present invention has applicability in the industrial field where resistors are generally used, for example, in the field of electronic equipment.

It is the side view which showed the process of an example of the manufacturing method of the resistor of this invention later on from (a) to (h). In the example of the method for manufacturing a resistor according to the present invention, an electrode piece-resistor piece-electrode piece and a state in which a member connected by bonding is cut into a piece-like member in order to obtain a size required for a unit resistor is shown. It is a top view. (A) shows before cutting, and (b) shows after cutting. It is a perspective view which shows the outline of the seam welding apparatus used for an example of the manufacturing method of the resistor of this invention, and its operation | movement.

Explanation of symbols

1. Electrode piece 2. Resistor piece 4. 4. Disc-shaped electrode for welding 6. Flat electrode for welding Weld marks 8. Piece member 9. Mold resin

Claims (5)

In the method of manufacturing a resistor in which a pair of electrode pieces are joined to opposite ends of a resistor piece,
After joining a single electrode piece and a resistor piece, it has the process of cutting or removing the electrode piece part which opposes a resistor piece surface other than the edge part which the said resistor piece opposes. Manufacturing method.   2. The method of manufacturing a resistor according to claim 1, wherein a gap is provided between the one surface of the resistor other than the opposing end portions of the resistor and the surface of the opposing electrode.   3. The method of manufacturing a resistor according to claim 2, wherein the formation of the gap is realized by an electrode piece shape.   4. The method of manufacturing a resistor according to claim 1, wherein the joining is performed by seam welding.   5. The method of manufacturing a resistor according to claim 1, wherein the resistor is a low resistor for current detection.

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