Soldering method

Abstract

To provide a method capable of performing smooth soldering which can efficiently heat a connection electrode of a printed wiring board surface by an iron tip even if a printed wiring board is multilayered having a large heat capacity.SOLUTION: This soldering method comprises: a first step of applying a flux FL to a connection electrode Ld; a second step of disposing an electronic component Ep in a printed wiring board Bd; a third step of moving an iron tip 5 having a solder hole 51 formed through into a roughly cylindrical shape in an axial direction and heatable relative to the printed wiring board Bd and setting a soldering position where a soldering scheduled part of a connection terminal P of the electronic component Ep disposed in the printed wiring board Bd and the connection electrode Ld to which the flux FL has been applied is positioned in the solder hole 51; a fourth step of supplying a solder piece into the solder hole 51 after the third step; a fifth step of heating and melting the solder piece supplied into the solder hole 51; and a sixth step of moving, in a relative manner, the iron tip 5 from the soldering position to a position away from the printed wiring board Bd after the fifth step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a soldering method, and more particularly to a method for soldering connection electrodes formed on a printed wiring board to connection terminals of an electronic component. [Background technology]

[0002] In recent years, most devices are equipped with printed circuit boards on which electronic components are mounted. In the manufacturing process of these printed circuit boards, soldering is performed to join various electronic components to the wiring patterns of the printed circuit board. In addition, various soldering devices have been proposed to mechanically perform the soldering process, and some of them are already in use.

[0003] For example, one proposed soldering device is one in which solder pieces, made by cutting wire solder to a predetermined length, are supplied into a solder hole that penetrates the axial direction of a cylindrical iron tip, and the solder pieces are heated and melted in the solder hole, and the molten solder is supplied downward to perform soldering (for example, Patent Document 1, etc.). In such devices, the connection electrodes are heated directly or indirectly by the contact of the iron tip with the printed wiring board or the connection electrodes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2008 / 023461 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the mounting density of electronic components on printed wiring boards has increased, and printed wiring boards are becoming increasingly multilayered. As the number of layers increases, the thermal capacity of the printed wiring board increases, and it takes time for the heat received from the soldering iron tip to reach the connection electrodes' melting temperature for the solder. If the connection electrodes are not heated sufficiently, there is a risk of soldering defects occurring.

[0006] The present invention has been made in consideration of these conventional problems, and its purpose is to provide a method that enables efficient heating of connection electrodes on the surface of a printed wiring board with an iron tip, even in the case of a multilayer printed wiring board with a large heat capacity, thereby enabling smooth soldering. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the inventor conducted extensive research and, noting the high thermal conductivity of flux, came up with the idea that by interposing flux between the iron tip and the connecting electrode, heat conduction from the iron tip to the connecting electrode would be smoother than before, which led to the creation of the present invention. That is, a soldering method according to one embodiment of the soldering method of the present invention is a method for soldering a connection electrode formed on a printed wiring board to a connection terminal of an electronic component arranged on the printed wiring board, and is characterized by comprising: a first step of applying flux to the connection electrode; a second step of arranging the electronic component on the printed wiring board; a third step of moving a heatable soldering iron tip that is approximately cylindrical and has a solder hole penetrating in the axial direction relative to the printed wiring board to position the soldering position where the portion to be soldered between the connection terminal of the electronic component arranged on the printed wiring board and the connection electrode to which the flux has been applied is located within the solder hole or axially below the solder hole; a fourth step of supplying a solder piece into the solder hole after the third step; a fifth step of heating and melting the solder piece supplied into the solder hole; and a sixth step of moving the soldering iron tip relatively from the soldering position to a position spaced apart from the printed wiring board after the fifth step.

[0008] In the soldering method having the above configuration, the application of the flux to the connection electrodes may be carried out by spraying the flux in the form of droplets.

[0009] In the soldering method configured as described above, the printed wiring board may be a multi-layer board.

[0010] In the soldering method having the above configuration, the solder pieces may be halogen-free. [Effects of the Invention]

[0011] According to the soldering method of the present invention, even in the case of a multilayer printed wiring board with a large heat capacity, the connection electrodes on the surface of the printed wiring board can be efficiently heated with the tip of the soldering iron, thereby enabling smooth soldering. [Brief explanation of the drawings]

[0012] [Figure 1] 1A to 1C are process diagrams illustrating a case where an insertion-mount type electronic component is mounted by a soldering method according to an embodiment of the present invention. [Figure 2] 1A to 1C are process diagrams illustrating a case where an insertion-mount type electronic component is mounted by a soldering method according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view of a mounting surface of a printed wiring board. [Figure 4] FIG. 2 is a perspective view of the surface (back surface) opposite to the mounting surface of the printed wiring board. [Figure 5] 1A to 1C are process diagrams illustrating a case where a surface-mount electronic component is mounted by a soldering method according to an embodiment of the present invention. [Figure 6] 1A to 1C are process diagrams illustrating a case where a surface-mount electronic component is mounted by a soldering method according to an embodiment of the present invention. [Figure 7] FIG. 2 is a schematic diagram of the soldering apparatus AP. [Figure 8] FIG. 2 is a perspective view showing the internal structure of the device main body A1. [Figure 9] FIG. 9 is a schematic vertical cross-sectional view of the device main body A1 shown in FIG. [Figure 10] 9 is an exploded perspective view of a part of a drive mechanism provided in the apparatus main body A1 shown in FIG. 8. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] The soldering method according to the present invention will be described in detail below, but the present invention is not limited to these embodiments. In the following embodiments, the direction perpendicular to the printed wiring board is referred to as the up-down direction, one direction perpendicular to the up-down direction is referred to as the left-right direction, and the direction perpendicular to the up-down direction and the left-right direction is referred to as the front-rear direction.

[0014] A soldering method according to an embodiment of the present invention is a method for soldering a connection electrode formed on a printed wiring board (hereinafter sometimes referred to as a "board") to a connection terminal of an electronic component arranged on the board.

[0015] Electronic components soldered to a substrate may be either an insertion-mount type or a surface-mount type. When an electronic component is an insertion-mount type, lands, which are connection electrodes formed around through holes formed in the substrate, are soldered to pin terminals, which are connection terminals of the electronic component. When an electronic component is a surface-mount type, pads, which are connection electrodes formed on the surface of the substrate, are soldered to leads, which are connection terminals of the electronic component. The leads of the electronic component may be gull-wing, J-lead, flat-lead, or any other type.

[0016] 3 and 4 show perspective views of the mounting surface and backside of a board Bd on which a mixture of insertion-mount type and surface-mount type electronic components is mounted. As shown in FIG. 3, pads Pd, through-holes Th, and lands Ld are formed on the mounting surface side of the board Bd, and as shown in FIG. 4, through-holes Th and lands Ld are formed on the backside of the board Bd. For insertion-mount type electronic components, pin terminals P of the electronic components are soldered to lands Ld on the backside of the board Bd. For surface-mount type electronic components, leads of the electronic components are soldered to pads Pd on the mounting surface side of the board Bd. For insertion-mount type and surface-mount type electronic components, one type of electronic component is generally mounted on the board Bd first, and then the other type of electronic component is mounted on the board Bd.

[0017] (Mounting of insertion-type electronic components to a circuit board) First, the process of mounting an insertion-mount type electronic component onto a substrate Bd will be described. (1st step) As shown in FIG. 1(a), first, flux FL is applied to the lands Ld on the back side of the substrate Bd (the lower side in FIG. 3, the upper side in FIG. 4). As shown in FIG. 1(b), the applied flux FL spreads uniformly at least over the lands Ld. Depending on the amount of flux FL applied, it may also spread over the solder resist SR. Flux FL can be applied to the lands Ld by conventional application methods. Examples include dispensers using air pulse or jet methods, and screen printing. Furthermore, using a multiple nozzle with multiple nozzles attached makes it possible to apply flux FL to multiple lands Ld at once, thereby increasing productivity.

[0018] The flux FL used in the present invention is not particularly limited, and any conventionally known flux can be used, such as a flux containing rosin as the main component to which an activator such as an organic amine hydrochloride is added, or a flux using a polymeric polyhydric alcohol such as ethylene glycol or propylene glycol instead of rosin.

[0019] (2nd process) Next, as shown in Fig. 1(c), an electronic component Ep is placed on a wiring board Bd. Specifically, pin terminals P of the electronic component Ep are inserted through through holes Th formed in the board Bd from the mounting surface side (lower side in the figure) of the board Bd toward the back surface side (upper side in the figure), and the main body of the electronic component Ep is placed on the mounting surface side of the board Bd. At this time, the pin terminals P protrude a predetermined length from the back surface (upper surface in the figure) of the board Bd. The pin terminals P may also be in contact with the inner wall (copper foil layer) of the through holes Th.

[0020] (3rd step) A heatable iron tip 5, which is roughly cylindrical and has a solder hole 51 penetrating in the axial direction, moves relatively closer to the board Bd, and the tip surface of the iron tip 5 comes into contact with the flux FL applied to the lands Ld and the solder resist SR of the board Bd. The pin terminals P of the electronic component Ep and the lands Ld coated with flux FL are positioned within the solder hole 51 of the iron tip 5. This position of the iron tip 5 is the soldering position.

[0021] 7, the soldering iron tip 5 is part of the soldering apparatus AP. The control means Cont controls the rotational movement of the articulated arm Am of the manipulator ML to move the soldering iron tip 5 of the apparatus main body A1 to a position where the axis of the soldering iron tip 5 is generally aligned with and spaced upward from the axis of the pin terminal P protruding from the board Bd. Thereafter, the control means Cont moves the soldering iron tip 5 in a direction that brings it into contact with the board Bd.

[0022] The tip surface of the iron tip 5 comes into contact with the flux FL applied to the lands Ld and the solder resist SR on the board Bd. Because the flux FL has a higher thermal conductivity than the solder resist SR, solder, and air, heat is quickly transferred from the iron tip 5, which is heated and maintained at a predetermined temperature, to the lands Ld via the flux FL, efficiently preheating even the lands Ld on a multilayered board with a large heat capacity.

[0023] (4th step) After the tip of the soldering iron tip 5 contacts the flux FL applied to the land Ld and the solder resist SR of the substrate Bd, a predetermined time elapses, and a solder piece Wh is supplied into the solder hole 51 of the soldering iron tip 5, as shown in FIG. 2(e). The time from when the soldering iron tip 5 contacts the substrate Bd until the solder piece Wh is supplied into the solder hole 51 may be the time it takes for the land Ld or the like to reach a predetermined temperature. Alternatively, the temperature of the substrate Bd or the land Ld may be detected and the solder piece Wh may be supplied once the predetermined temperature is reached. There are no particular limitations on the solder piece Wh used, and it may be halogen-free solder (containing 1000 ppm or less of each of the elements F, Cl, Br, and I), which is known to be prone to soldering defects. According to the method of the present invention, normal soldering is achieved even when halogen-free solder is used.

[0024] (5th step) The solder piece Wh supplied into the solder hole 51 melts due to the heat from the iron tip 5. In this embodiment, the gap between the outer periphery of the pin terminal P and the inner periphery of the solder hole 51 is set narrower than the outer diameter of the solder piece Wh. Therefore, when the solder piece Wh is supplied into the solder hole 51, its lower end abuts the tip of the pin terminal P and its upper end contacts the inner wall of the solder hole 51. Heat is transferred directly from the iron tip 5 to the solder piece Wh through the contact portion with the solder hole 51. Heat is also transferred to the solder piece Wh by radiation from the inner wall of the solder hole 51 and by convection within the solder hole 51. Then, as shown in FIG. 2( f ), when the melting temperature of the solder piece Wh is reached, the solder piece Wh melts and flows down, clinging to the pin terminal P and land Ld in a conical (fillet-like) shape. Some of the molten solder may reach the through hole Th and the land Ld on the opposite side.

[0025] Furthermore, when the gap between the outer periphery of the pin terminal P and the inner periphery of the solder hole 51 is set wider than the outer diameter of the solder piece Wh, the lower end of the solder piece Wh supplied into the solder hole 51 usually abuts against the land Ld and / or flux FL, and the outer periphery of the solder piece Wh is in contact with the inner wall of the solder hole 51. In this state, heat is transferred directly from the iron tip 5 to the solder piece Wh via the contact portion. In addition, heat is transferred from the iron tip 5 to the solder piece Wh also via the flux FL. For this reason, heat is transferred quickly from the iron tip 5 to the solder piece Wh, and the solder piece Wh can melt more quickly than if the solder piece Wh abutted against the tip of the pin terminal P.

[0026] (6th step) 2(g), after the molten solder flows down from the tip of the pin terminal P, the soldering iron tip 5 moves relatively from the soldering position in a direction away from the board Bd. The fillet-shaped molten solder is cooled by the outside air and solidifies while maintaining the fillet shape.

[0027] In the procedure for soldering the lands Ld and the pin terminals P described above, the first step of applying the flux FL to the lands Ld is followed by the second step of placing the electronic component Ep on the wiring board Bd, but the first and second steps may be reversed. That is, the flux FL may be applied to the lands Ld after the electronic component Ep is placed on the wiring board Bd.

[0028] (Mounting surface-mounted electronic components to a circuit board) The process of mounting surface-mounted electronic components onto a substrate Bd will be described. (2nd process) 5(a), an electronic component Ep having gull-wing leads Le is placed on a wiring board Bd. Specifically, the body of the electronic component Ep is placed on the mounting surface side of the board Bd so that the leads Le of the electronic component Ep are positioned on pads Pd formed on the board Bd.

[0029] (1st step) As shown in Figure 5(b), when flux FL is applied to pads Pd on which leads Le of an electronic component Ep are installed, the applied flux FL spreads over the leads Le and pads Pd, wetting them, as shown in Figure 5(c). The method exemplified above can be used to apply flux FL to lands Ld. A multiple nozzle with multiple nozzles attached can also be used.

[0030] As the flux FL to be used, the above-mentioned examples can also be used here.

[0031] (3rd step) A heatable iron tip 5, which is roughly cylindrical and has a solder hole 51 penetrating in the axial direction, moves relatively closer to the board Bd, and the tip surface of the iron tip 5 comes into contact with the lead Le of the electronic component Ep. At this time, the lead Le and pad Pd of the electronic component Ep, to which flux FL has been applied, are positioned below the solder hole 51 of the iron tip 5. This position of the iron tip 5 is the soldering position.

[0032] When the tip surface of the iron tip 5 comes into contact with the lead Le of the electronic component Ep to which flux FL has been applied, as mentioned above, the flux FL has a higher thermal conductivity than the solder resist SR, solder, and air, so heat is quickly transferred from the iron tip 5, which is heated and maintained at a predetermined temperature, to the lead Le and pad Pd via the flux FL, efficiently preheating even pads Pd on a multilayered board with a large heat capacity.

[0033] (4th step) After the tip surface of the soldering iron tip 5 contacts the lead Le of the electronic component Ep coated with flux FL, a predetermined time elapses, and a solder piece Wh is supplied into the solder hole 51 of the soldering iron tip 5, as shown in FIG. 6(e). The time from when the soldering iron tip 5 contacts the board Bd until the solder piece Wh is supplied into the solder hole 51 may be the time it takes for the pad Pd or the like to reach a predetermined temperature. Alternatively, the temperatures of the board Bd and the pad Pd may be detected and the solder piece Wh may be supplied once the predetermined temperature is reached. There are no particular limitations on the solder piece Wh used, and it may be halogen-free solder (containing 1000 ppm or less of each of the elements F, Cl, Br, and I), which is known to be prone to soldering defects. According to the method of the present invention, normal soldering is achieved even when halogen-free solder is used.

[0034] (5th step) When a solder piece Wh is supplied into a solder hole 51, its lower end abuts against the pad Pd via the flux FL, and the outer circumferential surface of the solder piece Wh is in contact with the inner wall of the solder hole 51. In this state, heat is transferred to the solder piece Wh from the pad Pd and the iron tip 5 via the contact portion. Heat is also transferred to the solder piece Wh by radiation from the inner wall of the solder hole 51 and by convection within the solder hole 51. For this reason, heat is transferred quickly from the iron tip 5 to the solder piece Wh, and the solder piece Wh can melt quickly. Then, as shown in FIG. 6(f), when the melting temperature of the solder piece Wh is reached, the solder piece Wh melts and flows down, clinging to the lead Le and pad Pd.

[0035] (6th step) 6(g), after the molten solder has flowed down, the soldering iron tip 5 moves relatively away from the soldering position and away from the board Bd. The molten solder clinging to the leads Le and pads Pd is cooled by the outside air and solidifies in that state.

[0036] (Overall configuration of soldering device) 7 is a perspective view of a soldering apparatus AP soldering an electronic component Ep to a substrate Bd. The substrate Bd is fixed to a jig Gj and has a plurality of through-holes Th formed therein, with lands Ld formed around the opening periphery of each through-hole Th. A pin terminal P extending from an electronic component Ep arranged on the back side of the substrate Bd is inserted from bottom to top into each through-hole Th, with the tip of the pin terminal P protruding from the top surface of the substrate Bd. The surface of the substrate Bd other than the lands Ld is covered with solder resist SR (shown in FIGS. 1 and 2).

[0037] The soldering apparatus AP used in the soldering method of the present invention includes a manipulator ML as a moving means having a multi-joint arm Am, an apparatus main 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 apparatus main body A1. The manipulator ML is mounted on a base Bs, and the multi-joint arm Am is rotatable at each of its multiple joints. The control device Cont controls the rotation of the multi-joint arm Am of the manipulator ML to move the apparatus main body A1 to a desired position in the X direction, Y direction, and up and down direction. The control device Cont also controls the operation of the cutter unit 2, drive mechanism 3, solder feed mechanism 6, and heater unit (heating means) 4 of the apparatus main body A1, which will be described later. In this embodiment, the cutter unit 2, drive mechanism 3, and solder feed mechanism 6 constitute a solder piece supplying means.

[0038] When soldering is performed using the soldering apparatus AP, the apparatus main body A1 is moved in the X and Y directions by the manipulator ML to position it relative to the lands Ld of the substrate Bd. Then, as the apparatus main body A1 is moved downward, the tip of the soldering iron tip 5 comes into contact with the lands Ld (or solder resist SR). In the embodiment described below, this soldering apparatus AP is used to position the pin terminals P protruding from the top surface of the substrate Bd within the solder holes 51 (shown in FIG. 3) of the soldering iron tip 5 of the apparatus main body A1, and then melt the solder pieces Wh supplied to the solder holes 51 of the soldering iron tip 5 to solder the pin terminals P and the lands Ld. While the apparatus main body A1 is moved in this embodiment, the apparatus main body A1 may be fixed and the substrate Bd may be moved, or both the apparatus main body A1 and the substrate Bd may be moved.

[0039] (Device body A1) Fig. 8 shows a perspective view of the device main body A1, Fig. 9 shows a vertical cross-sectional view of the soldering device shown in Fig. 8, and Fig. 10 is an exploded perspective view of a part of the drive mechanism provided in the soldering device shown in Fig. 8. In Fig. 8, part of the housing is cut away to show the inside of the device main body A1.

[0040] As shown in Figure 8, the device main body A1 has an device unit U, a support member SP that supports the device unit U so that it can move within a predetermined distance range in the vertical direction, and a cover C (waved line in Figure 2) that covers the device unit U and the support member SP.

[0041] The support member SP has a rectangular plane perpendicular to the X direction and includes a plate-shaped base Mf with a predetermined thickness in the X direction, a guide rail Mg with a predetermined width in the Y direction at the center of the Y direction on one side of the base Mf in the X direction, protruding in the X direction and continuing in the vertical direction, and a block Mb attached to the guide rail Mg so as to be movable in the vertical direction.

[0042] The upper and lower end portions of the base Mf are attached to the tip of the articulated arm Am of the manipulator ML. A wall 11 of the equipment unit U is attached to the block Mb over almost the entire vertical area. In other words, the equipment unit U is fixed to the block Mb and can move vertically together with the block Mb. In addition, a movement restriction pin 91 is provided at the lower end of one side surface of the block Mb in the Y direction, protruding vertically outward from the side surface.

[0043] On the other hand, rectangular parallelepiped upper and lower stopper portions 93 and 94 are provided at the Y-direction end positions of the lower vertical portion of one side surface in the X direction of the base Mf, facing each other at a predetermined distance in the vertical direction.

[0044] The movement restricting pin 91 provided on one side of the block Mb is located in the region between the upper stopper portion 93 and the lower stopper portion 94 of the base Mf, and in the initial state, i.e., when the iron tip 5 is not in contact with the wiring board Bd, the movement restricting pin 91 is in contact with the lower stopper portion 94 due to the weight of the device unit U and the block Mb. In other words, the movement of the device unit U in the downward vertical direction is restricted by the movement restricting pin 91 in contact with the lower stopper portion 94. On the other hand, when the iron tip 5 in contact with the wiring board Bd causes the device unit U to move upward in the vertical direction, the movement restricting pin 91 in the upward vertical direction is restricted by the movement of the device unit U in the upward vertical direction.

[0045] (Device Unit U) The device unit U includes a support portion 1 , a cutter unit 2 , a drive mechanism 3 , a heater unit 4 , a soldering tip 5 , and a solder feeding mechanism 6 .

[0046] The support part 1 has a flat wall 11 that is erected. In the following description, for convenience, the horizontal direction along the wall 11 is defined as the X direction, the horizontal direction perpendicular to the wall 11 is defined as the Y direction, and the vertical direction along the wall 11 is defined as the up-down direction, as shown in Fig. 2. For example, as shown in Fig. 2, the wall 11 has a plane that is perpendicular to the Y direction.

[0047] The support part 1 comprises a wall body 11, a holding part 12, a sliding guide 13, and a heater unit fixing part 14. The wall body 11 is a flat wall body erected in the vertical direction. The wall body 11 serves as a support member for the device main body A1. The holding part 12 is fixed at a position shifted upward from the lower end part of the wall body 11 in the vertical direction. The holding part 12 holds an air cylinder 31 (described later) of the drive mechanism 3. The heater unit fixing part 14 is a member that fixes the heater unit 4, and is provided at the end part (lower end part) of the wall body 11 in the vertical direction.

[0048] The sliding guide 13 is fixed near the lower end in the vertical direction of the wall body 11. The sliding guide 13 is fixed to the wall body 11 together with a lower cutter blade 22 (described later) of the cutter unit 2, and guides an upper cutter blade 21 (described later) of the cutter unit 2 so that it can slide in the X direction.

[0049] The sliding guides 13 are a pair of members facing each other in the Y direction. The sliding guides 13 have a pair of wall portions 131 and a retaining portion 132. The wall portions 131 are flat plate-shaped members extending in the X direction. One wall portion 131 is disposed in contact with the wall body 11, and the surface opposite the wall body 11 is in contact with the cutter lower end 22. The other wall portion 131 is in contact with a side surface of the cutter lower blade 22. In other words, the pair of wall portions 131 sandwich the cutter lower blade 22 from both sides in the Y direction. The pair of wall portions 131 and the cutter lower blade 22 are fastened together and fixed to the wall body 11 with fasteners such as screws.

[0050] The retaining portions 132 are provided on each of the pair of wall portions 131. The pair of wall portions 131 extend upward above the upper surface of the lower cutter blade 22, and extend from the upper end portions of the pair of wall portions 131 toward the other. That is, the sliding guide 13 is provided with a pair of retaining portions 132. The Y-direction tips of the pair of retaining portions 132 do not come into contact with each other. In other words, the sliding guide 13 has an opening at the top. At least a portion of the upper cutter blade 21 is disposed between the upper surface of the lower cutter blade 22 and the retaining portions 132. As a result, the upper cutter blade 21 is guided in the X direction and prevented from coming out in the upward direction.

[0051] The cutter unit 2 is a cutting tool that cuts the wire solder W fed by the solder feeding mechanism 6 into solder pieces Wh of a predetermined length. The cutter unit 2 includes an upper cutter blade 21, a lower cutter blade 22, and a pusher pin 23.

[0052] As described above, the lower cutter blade 22 is fixed to the wall 11 together with the sliding guide 13. As shown in FIG. 3 , the lower cutter blade 22 includes a lower blade hole 221 and a gas inlet hole 222. The lower blade hole 221 is a through-hole that vertically penetrates the lower cutter blade 22, and receives the solder wire W that has penetrated an upper blade hole 211 (described later) of the upper cutter blade 21. The upper edge of the lower blade hole 221 is formed like a cutting blade. The upper blade hole 211 and the lower blade hole 221 are used to cut the solder wire W into solder pieces Wh of a predetermined length. The cut solder pieces Wh fall downward inside the lower blade hole 221 by their own weight or by being pushed by the pusher pin 23. The lower blade hole 221 is connected to a solder hole 51 (described later) of the iron tip 5 via a solder supply hole 422 (described later) of the heater unit 4. The solder piece Wh that has fallen inside the lower blade hole 221 reaches the solder supply hole 422 and then falls into the solder hole 51.

[0053] The gas inlet hole 222 is a hole that connects the outer surface of the cutter lower blade 22 with the lower blade hole 221. Gas supplied from a gas supply source (not shown) flows into the gas inlet hole 222. The gas then passes through the lower blade hole 221 and the solder supply hole 422 and reaches the solder hole 51. The gas is used to suppress oxidation of the solder when the solder is heated and melted. In other words, it is a gas that suppresses contact between the molten solder and oxygen. Examples of the gas include nitrogen gas, argon gas, helium gas, and carbon dioxide. In the soldering apparatus AP of this embodiment, nitrogen gas is supplied.

[0054] As described above, the upper cutter blade 21 is disposed on the upper surface of the lower cutter blade 22. The upper cutter blade 21 is guided by the sliding guide 13 so that the sliding direction is the X direction when sliding, and is prevented from coming off upward. That is, the upper cutter blade 21 slides in the X direction on the upper surface of the lower cutter blade 22. The upper cutter blade 21 is slid by the drive mechanism 3.

[0055] The upper cutter blade 21 has an upper blade hole 211 and a pin hole 212. The upper blade hole 211 is a through-hole that passes through the upper cutter blade 21 in the vertical direction, and the wire solder W fed from the solder feed mechanism 6 is inserted into the upper blade hole 211. The edge portion at the lower end of the upper blade hole 211 is formed into a cutting blade shape. The pin hole 212 is a through-hole that passes through the upper cutter blade 21 in the vertical direction. A rod portion 231 (described later) of the pusher pin 23 is slidably inserted into the pin hole 212.

[0056] The pusher pin 23 has a rod portion 231, a head portion 232, and a spring 233. The rod portion 231 is a columnar member, and is slidably inserted into the pin hole 212. When the pusher pin 23 moves downward, the tip of the rod portion 23 protrudes from the pin hole 212. The head portion 232 is connected to the upper end of the rod portion 231 in the axial direction. The head portion 232 is a disk-shaped member having an outer diameter larger than the inner diameter of the pin hole 212. The head portion 232 is not inserted into the pin hole 212. In other words, the head portion 232 serves as a so-called stopper that limits the movement of the rod portion 231 into the pin hole 212.

[0057] The spring 233 is a compression coil spring that surrounds the radial outside of the rod portion 231. The lower end of the spring 233 contacts the upper surface of the cutter upper blade 21, and the upper end of the spring 233 contacts the lower surface of the head portion 232. That is, the spring 233 receives a reaction force from the upper surface of the cutter upper blade 21 and pushes the head portion 232 upward. As a result, the rod portion 231 connected to the head portion 232 is lifted upward, and the lower end of the rod portion 231 is maintained so as not to protrude from the lower end of the pin hole 212. A stopper (not shown) that prevents the rod portion 231 from coming out of the pin hole 212 is provided at the lower end of the rod portion 231.

[0058] The pusher pin 23 pushes downward the solder pieces Wh that have been cut by the upper cutter blade 21 and the lower cutter blade 22 and remain in the lower blade hole 221. The pusher pin 23 is constantly pushed upward, i.e., toward the opposite side from the lower cutter blade 22, by the elastic force of the spring 233. In other words, when the head portion 232 is pushed, the rod portion 231 protrudes downward from the lower end of the pin hole 212. The head portion 232 is then pushed by a cam member 33 of the drive mechanism 3, which will be described later.

[0059] In the upper cutter blade 21, the upper blade hole 211 and the pin hole 212 are arranged side by side in the X direction. When the upper cutter blade 21 slides in the X direction, it moves to a position where the upper blade hole 211 and the lower blade hole 221 overlap vertically, or to a position where the pin hole 212 and the lower blade hole 221 overlap vertically. The upper cutter blade 21 may slide such that the upper blade hole 211 and the lower blade hole 221 overlap when it slides to one sliding end, and the pin hole 212 and the lower blade hole 221 overlap when it slides to the other sliding end.

[0060] When the solder feed mechanism 6 feeds the wire solder W while the upper blade hole 211 and the lower blade hole 221 are vertically overlapping, the wire solder W that has passed through the upper blade hole 211 is inserted into the lower blade hole 221. As described above, the edge portion at the lower end of the upper blade hole 211 is formed like a cutting edge, and the edge portion at the upper end of the lower blade hole 221 is also formed like a cutting edge. The lower surface of the upper cutter blade 21 contacts the upper surface of the lower cutter blade 22. Therefore, when the wire solder W is inserted into the lower blade hole 221, the upper cutter blade 21 slides in the X direction, and the wire solder W is cut by the cutting edges of the upper blade hole 211 and the lower blade hole 221.

[0061] The upper cutter blade 21 is slid in the X direction by the cam member 33. Therefore, the upper cutter blade 21 and the pusher pin 23 are synchronized with the cam member 33. The cam member 33 pushes the head portion 232 when the pin hole 212 overlaps with the lower blade hole 221 in the vertical direction. Therefore, when the upper cutter blade 21 slides in the X direction, the tip of the rod portion 231 of the pusher pin 23 is housed in the pin hole 212. Therefore, when the upper cutter blade 21 slides in the X direction, the tip of the rod portion 231 is prevented from coming into contact with the upper surface of the lower cutter blade 22, and deformation, damage, etc. of the tip of the rod portion 231 and / or the lower cutter blade 22 is prevented.

[0062] As the cutter upper blade 21 slides in the X direction, the lower blade hole 211 and the pin hole 212 overlap in the vertical direction. With the pin hole 212 overlapping the lower blade hole 211, the head portion 232 is pushed by the cam member 33. This causes the pusher pin 23 to move downward. When the pusher pin 23 protrudes downward from the pin hole 212, a portion of the pusher pin 23 is inserted into the lower blade hole 211. If a solder piece (described below) remains at the entrance of the lower blade hole 211 after the wire solder has been cut, the tip of the pusher pin 23 will push the solder piece, causing it to fall.

[0063] As shown in Figures 8 and 9, the drive mechanism 3 includes an air cylinder 31, a piston rod 32, a cam member 33, a slider portion 34, and a guide shaft 35. The air cylinder 31 is held by the holder 12. The air cylinder 31 is cylindrical with a bottom. The piston rod 32 is housed inside the air cylinder 31, and is slidably driven (extends and retracts) by air pressure supplied from the outside. The air cylinder 31 and the piston rod 32 together form an actuator of the drive mechanism 3. The piston rod 32 is disposed inside the air cylinder 31, and a portion of the piston rod 32 always protrudes from one axial end (here, the lower end) of the air cylinder 31. The air cylinder 31 is held by the holder 12 so that the surface from which the piston rod 32 protrudes faces the cutter unit 2, i.e., faces downward.

[0064] The piston rod 32 passes through a through-hole (not shown) provided in the holding portion 12. The piston rod 32 is provided parallel to a guide shaft 35 and moves linearly back and forth along the guide shaft 35. The tip of the piston rod 32 is fixed to a cam member 33, and the extension and contraction of the piston rod 32 causes the cam member 33 to slide up and down. The sliding of the cam member 33 is guided by the guide shaft 35.

[0065] 9, the lower end of the guide shaft 35 is fitted into a recessed hole provided in the lower cutter blade 22, and is fixed to the lower cutter blade 22 with a screw 351. The upper part of the guide shaft 35 passes through a hole provided in the holder 12, and its movement is restricted by a pin 352. In other words, the guide shaft 35 is fixed to the lower cutter blade 22 by the screw 351, and to the holder 12 by the pin 352.

[0066] In this embodiment, the guide shaft 35 is fixed by the screw 351 and the pin 352, but this is not limited thereto and the guide shaft 35 may be fixed by a fixing method such as press fitting or welding. In this embodiment, the guide shaft 35 is a cylindrical member, but this is not limited thereto and the guide shaft 35 may have a cross-sectional polygonal shape, an ellipse, or the like.

[0067] 9 and 10, the cam member 33 is a rectangular member and includes a recess 330 formed by cutting out a portion of a long side in a rectangular shape, and a cylindrical support portion 331 connected to the cam member 33 and having a through-hole through which the guide shaft 35 passes. The slider portion 34 is slidably disposed in the recess 330 (in the X direction and the up-down direction). The support portion 331 extends parallel to the guide shaft 35 and is provided to suppress rattle of the cam member 33. In other words, if the cam member 33 has a certain thickness and is configured so as to be less likely to rattle, the cylindrical portion may be omitted and the support portion 331 may be formed only by a through-hole.

[0068] The cam member 33 includes a cylindrical pin 332 provided in the middle of the recess 330 and having a central axis perpendicular to the guide shaft 35, a pin pushing portion 333 adjacent to the recess 330 and pushing the pusher pin 23, and a bearing 334 disposed inside the support portion 331. The pin 332 is inserted into a cam groove 340 (described later) provided in the slider portion 34. The bearing 334 is fitted onto the guide shaft 35 and is a member that allows the cam member 33 to slide smoothly and without rattle.

[0069] As shown in Figures 9 and 10, the slider portion 34 is a rectangular plate-like member and is formed integrally with the cutter upper blade 21. The slider portion 34 has a cam groove 340 that penetrates the slider portion 34 in the plate thickness direction and extends in the longitudinal direction. The cam groove 340 has a first groove portion 341 on the upper side that extends parallel to the guide shaft 35, and a second groove portion 342 on the lower side that also extends parallel to the guide shaft 35. The first groove portion 341 and the second groove portion 342 are offset in the X direction, and the cam groove 340 has a connecting groove portion 343 that connects the first groove portion 341 and the second groove portion 342.

[0070] A pin 332 of the cam member 33 is inserted into the cam groove 340, and as the cam member 33 moves along the guide shaft 35, the pin 332 slides on the inner surface of the cam groove 340. When the pin 332 is positioned in the connecting groove portion 343 of the cam groove 340, it presses on the inner surface of the connecting groove portion 343. This causes the slider portion 34 and the cutter upper blade 21 formed integrally with the slider portion 34 to move (slide relative to the cutter lower blade 22) in a direction (X direction) intersecting the sliding direction of the cam member 33 (up-down direction).

[0071] In this embodiment, a configuration is described in which the cam member 33 has a pin 332 and the slide portion 34 has a cam groove 340, but in reality, the cam member may have a cam groove and the slide portion may have a pin.

[0072] In this embodiment, air pressure is used as the actuator for the drive mechanism 3, but this is not limited to this and it may be one that uses a fluid other than air (for example, hydraulic oil) (hydraulics). Also, this is not limited to using a fluid and it may be one that uses electricity, such as a motor or solenoid. In this embodiment, one actuator, a cam, and a cam groove are used to slide the cutter upper blade 21 and press down the pusher pin 23, but this is not limited to this. For example, multiple actuators (two) may be provided to slide the cutter upper blade 21 and press down the pusher pin 23.

[0073] As shown in Figures 8 and 9, the solder feed mechanism 6 supplies the wire solder W. The solder feed mechanism 6 includes a pair of feed rollers 61 and a guide tube 62. The pair of feed rollers 61 are rotatably attached to the support wall 11. The pair of feed rollers 61 feed the wire solder W downward by rotating while sandwiching the sides of the wire solder W between them. The pair of feed rollers 61 are biased toward each other, and the biasing force sandwiches the wire solder W between them. The length of the fed wire solder W is measured (determined) based on the rotation angle (number of rotations) of the feed rollers 61.

[0074] The guide tube 62 is an elastically deformable tube, and its upper end is located close to the portion of the feed roller 61 from which the wire solder W is fed. The lower end of the guide tube 62 is provided so as to communicate with the upper blade hole 211 of the upper cutter blade 21. The lower end of the guide tube 62 moves following the sliding of the upper cutter blade 21, and the guide tube 62 has a length and shape that prevents it from being excessively pulled or stretched within the range in which the upper cutter blade 21 slides.

[0075] The heater unit 4 is a heating device for heating and melting the solder pieces Wh, and is fixed to a heater unit fixing portion 14 provided at the lower end of the wall body 11, as shown in FIG. 3. The heater unit 4 includes a heater 41 and a heater block 42. The heater 41 generates heat when electricity is applied. Here, the heater 41 has an electric heating wire wound around the outer circumferential surface of the cylindrical heater block 42.

[0076] The heater block 42 has a cylindrical shape and is provided with a recess 421 with a circular cross section at its axial end for attaching the iron tip 5, and a solder supply hole 422 that penetrates from the center of the bottom of the recess 421 to the opposite side. The heater block 42 is provided in contact with the cutter lower blade 22 so that the solder supply hole 422 and the lower blade hole 221 communicate with each other. By providing the heater block 42 in this manner, the solder piece Wh moves from the lower blade hole 221 to the solder supply hole 422.

[0077] (trowel tip) The iron tip 5 is a cylindrical member with a solder hole 51 that penetrates axially through the center and has a circular cross section. The iron tip 5 is inserted into a recess 421 in the heater block 42 and is prevented from coming out by a member (not shown). The solder hole 51 in the iron tip 5 communicates with a solder supply hole 422 in the heater block 42, and solder pieces Wh are fed from the solder supply hole 422.

[0078] The iron tip 5 also has a release hole 53 above the area where the solder piece Wh melts, which connects the solder hole 51 to the outer circumferential surface. The release hole 53 serves to release nitrogen gas supplied from a gas supply unit (not shown) and vaporized flux FL to the outside of the iron tip 5 when the lower end opening of the solder hole 51 is blocked by molten solder.

[0079] Heat from the heater 41 is transferred to the iron tip 5, and the solder piece Wh is melted by the heat. For this reason, the iron tip 5 is made of a material with high thermal conductivity, for example, ceramics such as silicon carbide and aluminum nitride, or metals such as tungsten.

[0080] Although the soldering iron tip 5 in the device body A1 is cylindrical, it is not limited to this and may be a cylindrical tip with a polygonal or elliptical cross section. It is also possible to prepare a tip with a different shape to match the shape of the pin terminal P of the board Bd and / or electronic component Ep to be soldered. [Industrial Applicability]

[0081] According to the soldering method of the present invention, even in the case of a multilayer printed wiring board with a large heat capacity, the connection electrodes on the surface of the printed wiring board can be efficiently heated with the tip of the soldering iron, thereby enabling smooth soldering. [Explanation of symbols]

[0082] AP soldering equipment A1 Device body 11 Wall 12 Holding part 13 Sliding guide 14 Heater unit fixing part 15 Actuator holder 16 Spring retainer 2 cutter unit 21 Cutter upper blade 211 Upper blade hole 212 pinhole 22 Cutter lower blade 221 Lower blade hole 23 Pusher pin 231 Rod part 232 Head 233 Spring 3 Drive mechanism 31 Air Cylinder 32 Piston rod 33 Cam member 330 recess 331 Support hole 332 pins 333 Pin pressing part 334 Bearings 34 Slider section 340 Cam groove 341 First groove 342 Second groove 343 Connection groove 35 Guide shaft 4 heater units 41 Heater 42 heater block 421 Recess 422 Solder supply hole 5 trowel tip 51 Solder hole 6 Solder feed mechanism 61a, 61b Feed rollers 62 Guide tube Bd printed wiring board Ep electronic components FL Flux ML Manipulator Ld Land (connection electrode) Le Lead (connection terminal) P pin terminal (connection terminal) Pd pad (connection electrode) SR solder resist Th through hole Double wire solder Wh solder piece

Claims

1. A method for soldering a connection electrode formed on a printed wiring board to a connection terminal of an electronic component disposed on the printed wiring board, comprising: a first step of applying flux to the connection electrodes; a second step of arranging the electronic components on the printed wiring board; a third step of moving a heatable soldering iron tip having a substantially cylindrical shape and a solder hole penetrating in the axial direction relative to the printed wiring board to bring the soldering portion between the connection terminal of the electronic component arranged on the printed wiring board and the connection electrode coated with flux to a soldering position located within the solder hole or axially below the solder hole; a fourth step of supplying a solder piece into the solder hole after the third step; a fifth step of heating and melting the solder pieces supplied into the solder holes; a sixth step of relatively moving the soldering tip from the soldering position to a position spaced apart from the printed wiring board after the fifth step; A soldering method comprising the steps of:

2. 2. The soldering method according to claim 1, wherein the application of the flux to the connection electrodes is carried out by spraying the flux in the form of droplets.

3. 3. The soldering method according to claim 1, wherein the printed wiring board is a multi-layer board.

4. 3. The soldering method according to claim 1, wherein the solder pieces are halogen-free.

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