Soldering method

Abstract

The present invention provides a soldering method that allows a predetermined amount of solder to be applied to a desired area of ​​a planar terminal without the use of solder resist. [Solution] A soldering method for soldering a desired area of ​​a planar terminal, comprising: a first step of installing a plate-shaped flow suppressing member 1a so as to surround the periphery of the desired area AR of the terminal 21 in a plan view; a second step of bringing the tip of a cylindrical soldering iron tip 5 having a soldering hole 51 into contact with or close to the flow suppressing member 1a or the terminal 21; a third step of supplying solder pieces Wh to the soldering hole 51; and a fourth step of heating the soldering iron tip 5 to heat and melt the solder pieces Wh supplied to the soldering hole 51 and solder the desired area AR of the terminal 21.

Description

Technical Field

[0001] The present invention relates to a soldering method for soldering a desired area of a planar terminal.

Background Art

[0002] For example, when soldering a lead wire to a terminal, it has been proposed and actually used to supply a solder piece obtained by cutting a thread solder to a desired length into a solder hole of a cylindrical soldering tip, and heat the soldering tip to melt the solder piece in the solder hole for soldering (Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When applying a predetermined amount of solder to a desired area of a planar terminal using the aforementioned cylindrical soldering tip, depending on conditions such as the heating temperature of the terminal during soldering and the spread of the flux contained in the solder piece on the terminal surface, the melted solder may flow and spread beyond the desired area of the terminal.

[0005] To reliably prevent such spread of the melted solder, it is conceivable to apply a solder resist to portions other than the desired area of the terminal. However, applying a solder resist to the terminal in advance requires working time, labor, material costs, etc.

[0006] Therefore, an object of the present invention is to provide a soldering method capable of applying a predetermined amount of solder to a desired area of a planar terminal without using a solder resist.

Means for Solving the Problems

[0007] One embodiment of the soldering method according to the present invention for achieving the above objective is a soldering method for soldering a desired area of ​​a planar terminal, characterized by comprising: a first step of installing a plate-shaped flow suppressing member so as to surround at least a part of the periphery of the desired area of ​​the terminal in a plan view; a second step of bringing the tip of a cylindrical soldering iron tip having a soldering hole into contact with or close to the flow suppressing member or the terminal; a third step of supplying solder pieces to the soldering hole; and a fourth step of heating the soldering iron tip to heat and melt the solder pieces supplied to the soldering hole and solder the desired area of ​​the terminal.

[0008] In the soldering method of the above configuration, the flow suppressing member may have a through hole or notch, and in the first step, the flow suppressing member may be installed on the terminal such that the through hole or notch surrounds all or part of the periphery of the desired area.

[0009] Furthermore, in the soldering method of the above configuration, it is preferable that the flow suppressing member has non-wetting properties with respect to molten solder, at least on its surface. In this specification, "non-wetting properties" means that the contact angle with respect to the molten solder is greater than 90°. [Effects of the Invention]

[0010] According to the soldering method of the present invention, a predetermined amount of solder can be applied to a desired area of ​​a planar terminal without using solder resist. [Brief explanation of the drawing]

[0011] [Figure 1] This is a process diagram showing one embodiment of the soldering method according to the present invention. [Figure 2] This is a process diagram showing one embodiment of the soldering method according to the present invention. [Figure 3] This is a vertical cross-sectional view of the soldering iron tip 5, showing the change in the state of the solder piece within the solder hole. [Figure 4]This is a perspective view showing another embodiment of the flow suppression member used in the present invention. [Figure 5] This is a perspective view showing one embodiment of a soldering apparatus capable of carrying out the soldering method according to the present invention. [Modes for carrying out the invention]

[0012] The soldering method according to the present invention will be described in more detail below, but the present invention is not limited in any way to these embodiments. In this specification, "front-back direction," "left-right direction," and "up-down direction" mean the front-back direction, left-right direction, and up-down direction shown in each figure.

[0013] Figures 1 and 2 show process diagrams illustrating one embodiment of the soldering method according to the present invention. The soldering method shown in these figures is a process diagram for pre-forming a predetermined amount of solder (excess solder) SL (shown in Figure 2) in a desired area AR of a terminal 21 of a wiring 2 in which the surface of a strip-shaped conductor extending in the front-rear direction is covered with an insulating resin such as epoxy resin, and the front end is exposed to form a planar terminal 21.

[0014] First, as shown in Figure 1(a), the front end of the wiring 2, including the planar terminal 21, is positioned and fixed on the workbench 9. Specifically, a pair of pins 91a and 91b are provided on one edge of the upper surface of the rectangular parallelepiped workbench 9, spaced approximately the same width as the wiring 2. The wiring 2 is attached so as to be sandwiched between the pair of pins 91a and 91b.

[0015] A flow-inhibiting member 1a is attached to the terminal 21 of the wiring 2 (first step). The flow-inhibiting member 1a serves two purposes: to physically block the flow of molten solder and to reduce the fluidity of the molten solder by lowering the temperature of the terminal 21 heated by the soldering iron tip 5 described later. By physically blocking the flow of molten solder or reducing its fluidity, the flow-inhibiting member 1a prevents the molten solder from flowing and spreading across the surface of the terminal 21 beyond the desired region (dashed line in Figure 1(a)) AR.

[0016] The flow suppression member 1a used in this embodiment is a flat plate with a rectangular shape in plan view, whose length in the left-right direction is longer than that of the terminal 21, and whose length in the front-back direction is the same as or slightly shorter than that of the terminal 21, and which has a circular hole 11 that penetrates vertically through approximately the center in plan view. The inner diameter of the circular hole 11 is such that it can surround the desired area AR of the terminal 21. The flow suppression member 1a is attached to the terminal 21 such that the desired area AR on the terminal 21 is located within the circular hole 11 of the flat plate. The flow suppression member 1a attached to the terminal 21 has both left and right sides that protrude outward from the left and right ends of the terminal 21. This makes it easier for the heat transferred from the trowel tip 5 to the flow suppression member 1a to be released into the air. The flow suppression member 1a may be fixed to the workbench 9 with a fixing member (not shown).

[0017] The material of the flow suppressing member 1a may be a metal, resin, or other material, as long as its melting temperature is higher than the melting temperature of the solder (generally 180°C to 230°C) and it has a predetermined thermal conductivity. Furthermore, it is preferable that the flow suppressing member 1a is made of a material that is non-wettable to molten solder, or that its surface is coated with a non-wettable material.

[0018] The mounting position of the flow suppression member 1a is determined appropriately, taking into consideration the shape of the terminal 21 and the desired area AR on the terminal 21. For example, if a flat plate having a circular hole 11 is used as the flow suppression member 1a, the flow suppression member 1a is mounted on the terminal 21 such that the desired area AR on the terminal 21 is located within the circular hole 11 of the flat plate.

[0019] As shown in FIG. 1(b), the lower end (tip) of the cylindrical solder tip 5 having the solder hole 51 is brought into contact with the flow suppression member 1a (second step). It is preferable that the solder tip 5 is brought into contact with the flow suppression member 1a such that the central axis of the solder hole 51 penetrating vertically formed in the solder tip 5 and the central axis of the round hole 11 of the flow suppression member 1a are on the same line. Usually, the solder tip 5 is pre-heated by a heater H (shown in FIG. 3). When the solder tip 5 contacts the flow suppression member 1a, the flow suppression member 1a and the terminal 21 are heated. Of course, after the solder tip 5 contacts the flow suppression member 1a, the solder tip 5 may be heated by the heater H, but from the viewpoint of work efficiency, it is preferable that the solder tip 5 is pre-heated to a predetermined temperature.

[0020] There is no particular limitation on the relationship between the inner diameter of the round hole 11 of the flow suppression member 1a and the inner diameter of the solder hole 51 of the solder tip 5. One may be larger than the other, or both may have the same inner diameter. However, when the inner diameter of the solder hole 51 of the solder tip 5 is larger than the inner diameter of the round hole 11 of the flow suppression member 1a, the molten solder contacts the surface periphery of the round hole 11 of the flow suppression member 1a. Therefore, it is preferable that the surface of the flow suppression member 1a has non-wettability to the molten solder.

[0021] As shown in FIG. 1(c), when the flow suppression member 1a and the terminal 21 are heated to a predetermined temperature or higher, a solder piece Wh is supplied into the solder hole 51 of the solder tip 5 from a solder piece supply part (not shown) (third step). The solder piece Wh is cylindrical with a predetermined outer diameter and axial length. The outer diameter of the solder piece Wh is made less than the inner diameter of the solder hole 51. The volume of the mound solder SL formed on the surface of the terminal 21 is determined by at least one of the outer diameter and length of the solder piece Wh. In addition, the timing control such as the supply of the solder piece Wh is controlled using the detected temperature of the solder tip 5 as an index. Alternatively, for example, it may be controlled using time as an index based on the time when the solder tip 5 contacts the flow suppression member 1a.

[0022] As shown in Figure 2(a), the solder pieces Wh supplied into the solder holes 51 are heated above their melting temperature and melt, and spread over the terminal 21 due to the action of the flux contained in the solder pieces Wh (fourth step). Since the desired region AR on the terminal 21 is surrounded by the circular holes 11 of the flow suppression member 1a, the molten solder does not spread outside the circular holes 11. However, if the fluidity of the molten solder is low, it may remain within the desired region AR without being restricted by the circular holes 11 of the flow suppression member 1a.

[0023] As shown in Figure 2(b), after the solder piece Wh melts and spreads over the terminal 21, the soldering iron tip 5 moves upward away from the flow-suppressing member 1a. As the soldering iron tip 5 moves upward away, the molten solder is exposed to the outside air and solidifies rapidly. Subsequently, the flow-suppressing member 1a moves upward away from the surface of the terminal 21, and a pile of solder SL formed in the desired region AR appears on the terminal 21.

[0024] Figure 3 shows a vertical cross-sectional view of the soldering iron tip 5 including the center line of the soldering hole 51 to illustrate the change in the state of the solder piece Wh within the soldering hole 51. As shown in Figure 3(a), the solder piece Wh supplied into the soldering hole 51 of the soldering iron tip 5 has its lower end in contact with the surface of the terminal 21 and its upper end in contact with the inner wall of the soldering hole 51. The solder piece Wh then melts due to heating by the soldering iron tip 5 (heat transfer, radiant heat, convective heat). As shown in Figure 3(b), the molten solder piece Wh spreads through the round hole 11 of the flow suppression member 1a, wetting the surface of the terminal 21. The spread of the molten solder is restricted to a desired area AR by the flow suppression member 1a. As shown in Figure 3(c), when the soldering iron tip 5 moves away from the flow suppression member 1a, the molten solder is cooled by the outside air and solidifies. Next, the flow suppression member 1a is removed from the surface of the terminal 21. Through this process, the solder pile SL is formed within the desired area AR on the surface of the terminal 21.

[0025] Figure 4 shows another embodiment of the flow suppression member used in the present invention. The flow suppression member 1b shown in Figure 4(a) is a rectangular plate material having a rectangular through-hole 12 that penetrates vertically through the center. The area of ​​the through-hole 12 is larger than the desired region AR of the terminal 21. The flow suppression member 1b is installed on the terminal 21 such that the through-hole 12 surrounds the desired region AR.

[0026] The flow-suppressing member 1c shown in Figure 4(b) is a rectangular plate material having a rectangular notch 13 extending forward from the center of the rear edge. The width of the notch 13 is the same as or wider than the width of the desired region AR. The flow-suppressing member 1c is attached to the terminal 21 so that the side of the notch 13 is positioned in the direction of molten solder flow. This prevents the molten solder from flowing beyond the desired region AR. Alternatively, the flow-suppressing member 1c is attached so that it contacts a part of the terminal 21 where the temperature is high. This lowers the temperature of the part of the terminal 21 in contact with the flow-suppressing member 1c, cooling the molten solder and suppressing its flow.

[0027] The flow-suppressing member 1d shown in Figure 4(c) is a long, strip-shaped plate material. When a flat terminal 21 is provided at the front end of the wiring 2 as shown in this figure, the front end of the terminal 21 tends to be hotter than the center of the wiring 2. Therefore, the flow-suppressing member 1c is attached to the front end of the terminal 21. This lowers the temperature of the part of the terminal 21 in contact with the flow-suppressing member 1c, cooling the molten solder and suppressing its flow. At the same time, the flow of molten solder toward the front is physically blocked by the flow-suppressing member 1c.

[0028] The material of the flow-suppressing member shown in Figure 4 can also be the same as the example given above.

[0029] (Soldering device) An embodiment of a soldering apparatus capable of carrying out the soldering method according to the present invention will be described. Figure 5 shows a perspective view of the soldering apparatus. The soldering apparatus AP shown in this figure comprises a manipulator ML as a moving means having a multi-joint arm Am, a device body A1 attached to the tip of the manipulator ML, and a control device Cont that controls the operation of the manipulator ML and the device body A1. The manipulator ML is installed on a base Bs, and the multi-joint arm Am is rotatable at each of its multiple joints. The control device Cont controls the rotational movement of the multi-joint arm Am of the manipulator ML to move the device body A1 to a desired position in the X, Y, and Z directions. The control device Cont also controls the operation of a cutter unit, a drive mechanism, a solder feeding mechanism, and a heater H (shown in Figure 3) built into the device body A1.

[0030] The connection unit 4, which protrudes downward from the bottom surface of the main body A1 of the device, is a unit for detachably attaching the soldering iron tip 5. As shown in Figure 3, the connection unit 4 has a cylindrical shape and is equipped with a circular cross-section recess 41 at its axial end for attaching the soldering iron tip 5, and a solder supply hole 42 that penetrates from the center of the bottom of the recess 41 to the opposite side. The soldering iron tip 5 is inserted into the recess 41 of the connection unit 4 and is secured by a component not shown in the figure. The solder hole 51 of the soldering iron tip 5 communicates with the solder supply hole 42 of the connection unit 4. Solder pieces Wh, cut to a predetermined length by a cutter unit, solder feeding mechanism, etc., built into the main body A1 of the device, are supplied from the solder supply hole 42 to the solder hole 51.

[0031] A heater H is wrapped around the outer circumference of the connection unit 4. The heater H generates heat when electricity is applied, and serves as a heat source to heat and melt the solder piece Wh supplied into the solder hole 51.

[0032] The trowel tip 5 receives heat from the heater H, which melts the solder piece Wh. Therefore, the trowel tip 5 is made of a material with high thermal conductivity, such as ceramics like silicon carbide or aluminum nitride, or metals like tungsten. In the main body A1 of the apparatus, the trowel tip 5 is cylindrical, but it is not limited to this, and a cylindrical shape with a polygonal or elliptical cross-section may also be used.

[0033] When soldering is performed using the soldering device AP, the device body A1 is moved in the X and Y directions by the manipulator ML to position it relative to the terminals 21 of the wiring 2 attached to the workbench 9. Then, when the device body A1 is moved in the Z direction, the lower end of the soldering iron tip 5a comes into contact with the flow suppression member 1a. In this embodiment, the device body A1 is moved, but the device body A1 may be fixed and the workbench 9 may be moved, or both the device body A1 and the workbench 9 may be moved.

[0034] The soldering iron tip 5 comes into contact with the flow-suppressing member 1a, and after the flow-suppressing member 1a and the terminal 21 are heated by the soldering iron tip 5, a solder piece Wh is supplied to the soldering hole 51 of the soldering iron tip 5. The solder piece Wh is then heated and melted within the soldering hole 51, forming a solder pile SL at the desired position AR on the terminal 21. Subsequently, the device body A1 is moved upward in the Z direction by the manipulator ML, causing the lower end of the soldering iron tip 5 to separate from the flow-suppressing member 1a.

[0035] The movement control of the trowel tip 5 by the control means Cont may be performed based on a value that has been input and set in advance, or it may be performed based on a detection signal from a detection means not shown, such as a contact sensor. [Industrial applicability]

[0036] According to the soldering method of the present invention, a predetermined amount of solder can be applied to a desired area of ​​a planar terminal without using solder resist. [Explanation of Symbols]

[0037] 1a, 1b, 1c, 1d Flow suppression member 2 Wiring 5. Trowel tip 11 Round hole (through hole) 12 Through holes 13 Notches 21 terminals 51 Solder holes AR desired area Wh solder piece

Claims

1. A soldering method for soldering a desired area of ​​a planar terminal, In a plan view, the first step is to install a plate-shaped flow suppression member so as to surround at least a part of the periphery of the desired area of ​​the terminal, A second step involves bringing the tip of a cylindrical soldering iron tip having a soldering hole into contact with or close to the flow suppression member or the terminal, A third step of supplying solder pieces to the aforementioned solder holes, A fourth step involves heating the soldering iron tip to heat and melt the solder piece supplied to the solder hole, thereby soldering it to a desired area of ​​the terminal. A soldering method characterized by having [a certain feature].

2. The soldering method according to claim 1, wherein the flow suppressing member has a through hole or a notch, and in the first step, the flow suppressing member is installed on the terminal such that the through hole or the notch surrounds all or part of the periphery of the desired area.

3. The soldering method according to claim 1 or 2, wherein the flow suppressing member has non-wetting properties with respect to molten solder, at least on its surface.

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