Iron tip, soldering device equipped with same, and method for determining the state of the iron tip

Abstract

To provide an iron tip which can quickly discharge fume generated from molten solder to the outside, can prevent the discharged fume from contacting electronic components in the periphery on a printed circuit board and further prevents the molten solder from flowing to the outside from an exhaust hole.SOLUTION: An iron tip 5a can be detachably attached to a device body A1 having a heater unit 4, and comprises: a columnar body part 50; a solder hole 51 which penetrates in an axial direction of the body part 50 and is supplied with a solder piece Wh; and an exhaust hole 53a whose one end is open in an inner peripheral surface of the solder hole 51 and the other end is open in an outer peripheral surface of the body part 50. The solder hole 51 has a melting region D where the solder piece Wh is molten. An opening 54 on an inner peripheral surface side of the exhaust hole 53a is located in the melting region D. An opening 55 on an outer peripheral surface side of the exhaust hole 53a is located above the opening 54 on the inner peripheral surface side of the exhaust hole 53a.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a soldering iron tip, a soldering device including the same, and a method for determining the state of the soldering iron tip. [Background technology]

[0002] In recent years, many devices are equipped with printed circuit boards (hereinafter simply referred to as "boards") on which electronic components are mounted. In the board fabrication process, soldering is performed to connect lead wires to the wiring pattern on the board.

[0003] As a device capable of efficiently performing soldering processing, the inventor has proposed a soldering device in which a solder piece is supplied into a solder hole formed in the tip of a cylindrical iron and the solder piece is melted by the heat of the iron tip (Patent Document 1, etc.).

[0004] In practice, the tip of such a soldering device is provided with an exhaust hole (release hole) that connects the inner surface of the solder hole with the outer surface of the tip of the soldering device, allowing fumes (vaporized flux) generated from the solder piece when the solder piece is heated and melted to be discharged from the solder hole to the outside.

[0005] The applicant has also proposed a method for determining the state of an iron tip having an exhaust hole based on changes in the pressure of the gas flowing through a solder hole while keeping the total flow rate of an inert gas such as nitrogen supplied into the solder hole constant (Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5184359 [Patent Document 2] Japanese Patent Application Publication No. 2019-166541 Summary of the Invention [Problem to be solved by the invention]

[0007] Previously, exhaust holes formed in the tip of soldering irons were formed perpendicular to the solder piece supply direction. Furthermore, the vertical position of the exhaust hole was set close to the solder piece supplied to the solder hole, in other words, close to the surface of the board, from the viewpoint of efficiently discharging fumes to the outside. Meanwhile, many electronic components are densely arranged on the board, and other electronic components are also arranged around the electronic components to be soldered on the board.

[0008] Under these circumstances, if the fumes generated when the solder pieces are heated and melted are exhausted to the outside through the exhaust holes formed in the tip of the iron, the fumes may hit the surrounding electronic components and cause adverse effects. Also, depending on the position of the exhaust holes, there is a risk that the molten solder may leak out of the exhaust holes.

[0009] On the other hand, if the exhaust hole is positioned further up and down from the board surface, i.e., upstream (upper in the vertical direction) in the direction of solder piece supply from the iron tip, it is thought that fumes emitted from the exhaust hole of the iron tip will be less likely to hit surrounding electronic components, but there is a risk that the fumes will not be quickly exhausted from the solder hole. Also, the speed at which pressure changes in the solder hole due to changes in the state of the iron tip are detected will be slow, or the amount of pressure change will be small, which could reduce the accuracy of determining the state of the iron tip.

[0010] Therefore, the object of the present invention is to provide an iron tip that can quickly exhaust to the outside fumes generated from solder pieces when they melt, can prevent the exhausted fumes from hitting surrounding electronic components on the board, and does not allow molten solder to leak to the outside through the exhaust hole.

[0011] Another object of the present invention is to provide a soldering device that can prevent fumes emitted from the soldering iron tip from hitting electronic components on a circuit board.

[0012] Another object of the present invention is to provide a method for determining the condition of an iron tip, which can quickly and accurately determine the condition of the iron tip. [Means for solving the problem]

[0013] The soldering tip of the present invention, which achieves the above-mentioned object, is an iron tip that can be detachably attached to an apparatus body having a heat source, and is characterized in that it has a columnar main body, a solder hole that penetrates the main body in the axial direction and through which solder pieces are supplied, and an exhaust hole that has one end opening on the inner surface of the solder hole and the other end opening on the outer surface of the main body, the solder hole has a melting area in which the solder pieces melt, the opening on the inner surface of the exhaust hole is located in the melting area, and the opening on the outer surface of the exhaust hole is located higher than the opening on the inner surface.

[0014] In the iron tip having the above configuration, it is preferable that the exhaust hole has an inclined portion, and the angle formed by the inclined portion with the axis of the main body is preferably in the range of 10° to 85°.

[0015] The soldering device of the present invention that achieves the above-mentioned object comprises an iron tip as described above and an apparatus main body to which the iron tip is detachably attached, and the apparatus main body is characterized in that it is equipped with a heat source for heating the iron tip and a solder piece supply unit for supplying solder pieces to the solder hole.

[0016] In the soldering device having the above configuration, it is preferable that the device main body further includes a gas supply source that supplies gas, a gas supply unit that connects the gas supply source to the solder hole and supplies gas from the gas supply source to the solder hole, and a measurement unit that measures the pressure of the gas flowing within the solder hole.

[0017] The method for determining the state of the soldering iron tip of the present invention, which achieves the above-mentioned object, is a method for determining the state of the soldering iron tip of the soldering device described above, characterized in that the flow rate of gas flowing through the solder hole is constant, the pressure of the gas flowing within the solder hole is measured, and the measured pressure is compared with a pre-prepared reference value or table to determine the state of the soldering iron tip. [Effects of the Invention]

[0018] The iron tip of the present invention can quickly exhaust fumes generated from molten solder pieces to the outside, prevent the exhausted fumes from hitting surrounding electronic components on the board, and prevent molten solder from leaking out through the exhaust hole.

[0019] Furthermore, the soldering device of the present invention can prevent fumes emitted from the soldering iron tip from hitting electronic components on a circuit board.

[0020] Furthermore, according to the method for determining the state of the iron tip of the present invention, the state of the iron tip can be determined quickly and accurately. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a vertical cross-sectional view showing an embodiment of an iron tip according to the present invention. [Figure 2] 2 is a vertical cross-sectional view of the lower part of the iron tip 5a of FIG. 1. [Figure 3] 10 is a partial vertical cross-sectional view of the tip of the iron showing another form of exhaust hole. FIG. [Figure 4] FIG. 10 is a vertical cross-sectional view showing another embodiment of the trowel tip. [Figure 5] 1 is a perspective view showing an embodiment of a soldering apparatus AP according to the present invention. [Figure 6] FIG. 2 is a perspective view showing the internal structure of the device main body A1. [Figure 7] FIG. 7 is a schematic vertical cross-sectional view of the device main body A1 shown in FIG. [Figure 8] 7 is an exploded perspective view of a part of a drive mechanism provided in the apparatus main body A1 shown in FIG. 6. FIG. [Figure 9] FIG. 2 is a partial vertical cross-sectional view of the iron tip when it is in a standard state. [Figure 10] FIG. 10 is a partial vertical cross-sectional view of the iron tip in the iron tip contact state. [Figure 11] FIG. 2 is a partial vertical cross-sectional view of the tip of the soldering iron in a solder piece insertion state. [Figure 12] FIG. 2 is a partial vertical cross-sectional view of the tip of the soldering iron when the solder piece is in a molten state. [Figure 13]FIG. 10 is a partial vertical cross-sectional view of the soldering tip when the solder piece is in a flowing state. [Figure 14] FIG. 2 is a partial vertical cross-sectional view of the iron tip in a separated state. [Figure 15] FIG. 10 is a diagram showing the change in pressure inside a solder hole when a soldering device performs a single soldering process. [Figure 16] This is a diagram showing a state in which a solder piece Wh is inserted into a dirty solder hole. [Figure 17] 10 is a diagram showing a state when determining the soldering state between a land and a pin terminal. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] The soldering iron tip, the soldering device using the same, and the method for determining the state of the soldering iron tip according to the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in this specification, the "vertical direction" refers to the vertical direction shown in Figure 1, and the "vertical direction" refers to the vertical direction in the direction of gravity.

[0023] (trowel tip) Fig. 1 shows a vertical cross-sectional view including a central axis C1 of an embodiment of an iron tip according to the present invention, and Fig. 2 shows an enlarged vertical cross-sectional view of the lower part of the iron tip of Fig. 1 in a state where the lower end of the iron tip is in contact with the surface of a board and a solder piece is supplied into a solder hole.

[0024] The iron tip 5a shown in Fig. 1 has a cylindrical main body 50, a solder hole 51 that penetrates the main body 50 in the vertical direction with a central axis C1 of the main body 50 as its common central axis, and an exhaust hole 53a that has openings 54, 55 on the inner peripheral surface of the solder hole 51 and the outer peripheral surface of the main body 50. An expanded diameter portion 510 is provided at the bottom of the solder hole 51 via a step. This expanded diameter portion 510 is provided to make it easier to insert pin terminals P protruding from the surface of the board CB into the solder hole 51. Note that the expanded diameter portion 510 may have a shape that continuously expands radially outward toward the bottom end of the iron tip 5a.

[0025] Opening 55 of exhaust hole 53a is located vertically above opening 54, and exhaust hole 53a is entirely inclined at a predetermined angle θ with respect to central axis C1 (the entire exhaust hole is an inclined portion). There are no particular limitations on inclination angle θ, and it may be determined appropriately based on the size and shape of soldering iron tip 5a and the size (height) and shape of the electronic component on board CB to be soldered. Typically, angle θ of the inclined portion of exhaust hole 53a is preferably in the range of 10° to 85°, and more preferably in the range of 45° to 80°.

[0026] Furthermore, the opening 54 of the exhaust hole 53a is located in the melting region D (shown in FIG. 2) of the solder hole 51. Here, the melting region D is a region where the solder piece Wh supplied to the solder hole 51 can melt. In this embodiment, the melting region D is a region from the upper end to the lower end of the solder piece Wh that stands in the solder hole 51 and abuts on the tip end of the pin terminal P protruding from the surface of the substrate CB. There are no particular limitations on the shape or size of the cross section perpendicular to the axis of the exhaust hole 53a, and it may be determined appropriately based on the volume of the solder piece Wh, the thickness of the main body 50, etc.

[0027] A pressure measurement hole 52 is provided at the top of the iron tip 5a, connecting the solder hole 51 to the outer peripheral surface. The pressure measurement hole 52 is a hole for measuring the pressure inside the solder hole 51. As shown in FIG. 7 , when the iron tip 5a is attached to the recess 421 of the heater block 42 of the apparatus main body A1, the outer opening of the pressure measurement hole 52 connects to a through hole 423 that connects the inner peripheral surface and outer peripheral surface of the recess 421. One end of a pressure measurement pipe 8 is connected to the outer peripheral surface opening of the through hole 423, and the pressure measurement hole 52 is connected to the pressure measurement pipe 8 via the through hole 423. Note that the pressure measurement pipe 8 may be directly connected to the pressure measurement hole 52; however, a configuration in which the pressure measurement hole 52 is indirectly connected to the pressure measurement pipe 8 via the through hole 423 is preferred because it eliminates the need to detach the pressure measurement pipe 8 from the iron tip 5a when attaching or detaching the iron tip 5a to or from the apparatus main body A1. The inner diameter of pressure measurement hole 52 is set smaller than the inner diameter of solder hole 51. That is, pressure measurement hole 52 has a larger flow path resistance than solder hole 51. Pressure measurement hole 52 is formed above exhaust hole 53a. This reduces contamination of pressure measurement hole 54 by fumes.

[0028] (Other types of exhaust vents) Figure 3 shows another type of exhaust hole formed in the main body of the iron tip. Exhaust hole 53b shown in Figure 3(a) is composed of two inclined portions 531 and 532 with different inclination angles. The angle θ1 of inclined portion 531 is larger than the angle θ2 of inclined portion 532, and exhaust hole 53b slopes gently upward from the inner surface of solder hole 51 toward the outside in the radial direction, and then slopes at a steeper angle. This type of exhaust hole 53b can be formed when it is desired to exhaust fumes as far upward as possible to prevent them from hitting adjacent electronic components.

[0029] 3(b) is composed of an inclined portion 533 and a horizontal portion 534. Exhaust hole 53c having such a configuration can be formed when it is desired to make the direction in which fumes are discharged from exhaust hole 53c as horizontal as possible.

[0030] 3(c) is composed of two horizontal portions 535, 536 and one connecting portion 537, and has a structure in which the radially outer end of the horizontal portion 535 and the radially inner end of the horizontal portion 536 are connected by the vertical connecting portion 537. The connecting portion 537 may be vertical or may be inclined upward toward the radially outer side of the trowel tip 5d.

[0031] (Other trowel tips) Figure 4 shows another embodiment of the iron tip according to the present invention. The iron tip 5e shown in Figure 4(a) has the same basic structure as the iron tip 5a shown in Figure 1, but differs in that two exhaust holes 53a are provided in the main body 50. By providing two exhaust holes 53 in the main body 50, fumes and the like can be quickly discharged from the solder holes 51. Note that the number of exhaust holes 53a formed in the main body 50 may be three or more. Furthermore, the positions of the multiple exhaust holes 53a may be either vertical or circumferential, as long as the configuration of the present invention is satisfied.

[0032] 1, the iron tip 5f shown in Fig. 4(b) has a cylindrical main body 50, a solder hole 51 that penetrates the main body 50 in the vertical direction about the central axis C1, and an exhaust hole 53a that has openings 54, 55 on the inner surface of the solder hole 51 and the outer surface of the main body 50. However, unlike the iron tip 5a shown in Fig. 1, the iron tip 5f does not have an expanded diameter portion 510 at the bottom of the solder hole 51, and has a gas release hole 59 at the top of the main body 50 that has openings on the inner surface of the solder hole 51 and the outer surface of the main body 50.

[0033] The reason why the soldering iron tip 5a shown in Figure 1 has the enlarged diameter portion 510 is mainly to increase the insertion tolerance of the pin terminal P protruding from the board CB into the solder hole 51 when soldering the pin terminal P to the board CB. However, when connecting a pad (flat electrode) on the board CB to the terminal of an electronic component, the enlarged diameter portion 510 at the bottom of the solder hole 51 is not particularly necessary, and the soldering iron tip 5f shown in Figure 4(b) may not have the enlarged diameter portion 510.

[0034] In the soldering apparatus AP described below, an inert gas such as nitrogen gas is supplied to the solder hole 51 to prevent oxidation of the molten solder. In such a soldering apparatus AP, if the solder melted in the solder hole 51 completely blocks the solder hole 51 and the exhaust hole 53a, the internal pressure of the solder hole 51 may become extremely high. Therefore, the iron tip 5e is provided with a gas release hole 59 to prevent the internal pressure of the solder hole 51 from becoming extremely high. The inner diameter of the gas release hole 59 is set smaller than the inner diameter of the solder hole 51. That is, the gas release hole 59 has a higher flow resistance than the solder hole 51. Even if a solder piece Wh melted in the solder hole 51 completely blocks the solder hole 51 and the exhaust hole 53a, the molten solder usually flows down in a short time, and at least one of the solder hole 51 and the exhaust hole 53a is released from the blockage by the molten solder. Therefore, the gas release hole 59 does not need to be provided.

[0035] (Overall configuration of soldering device) A soldering apparatus using the soldering iron tip 5a according to the present invention will be described below. Fig. 5 is a perspective view of a soldering apparatus AP that performs soldering using the soldering iron tip 5a. The soldering apparatus AP solders an electronic component Ep to a board CB. Four through holes Th are formed in the board CB, which is fixed to a jig Gj, and lands Ld are formed on the inner surface and periphery of each through hole Th. Four pin terminals P extending from electronic components Ep arranged on the back side of the board CB are inserted from bottom to top into each of the four through holes Th, with the tips of the pin terminals P protruding from the top surface of the board CB.

[0036] The soldering apparatus AP 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, Y, and Z directions. The control device Cont also controls the operation of the cutter unit 2, drive mechanism 3, solder feed mechanism 6, and heater unit (heat source) 4 of the apparatus main body A1 shown in FIG. 6. In this embodiment, the cutter unit 2, drive mechanism 3, and solder feed mechanism 6 constitute a solder piece supplying means.

[0037] 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 CB. Then, by moving the apparatus main body A1 in the Z direction, the tip of the soldering iron tip 5a comes into contact with the substrate CB. 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 CB within the solder holes 51 of the soldering iron tip 5a of the apparatus main body A1, and then melt the solder pieces Wh supplied to the solder holes 51 of the soldering iron tip 5a 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 CB may be moved, or both the apparatus main body A1 and the substrate CB may be moved.

[0038] Such movement control by the control means Cont of the iron tip 5 may be performed based on a preset input value, or based on a detection signal from a detection means (not shown) such as a contact sensor.

[0039] (Device body A1) Fig. 6 shows a perspective view of the device main body A1, Fig. 7 shows a vertical cross-sectional view of the device main body A1 shown in Fig. 6, and Fig. 8 is an exploded perspective view of a part of the drive mechanism provided in the device main body A1 shown in Fig. 6. In Fig. 6, a part of the housing is cut away to show the inside of the device main body A1.

[0040] As shown in Figure 6, 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 Z direction, and a cover C (dashed line in Figure 6) that covers the device unit U and the support member SP.

[0041] The support member SP includes a plate-like base Mf having a rectangular YZ plane and a predetermined thickness in the X direction, a guide rail Mg having 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 Z direction, and a block Mb attached to the guide rail Mg so as to be movable in the Z direction.

[0042] The upper end of the base Mf in the Z direction is 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 area in the Z direction. In other words, the equipment unit U is fixed to the block Mb and can move in the Z direction 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 position of the lower Z-direction on one side surface in the X-direction of the base Mf, facing each other at a predetermined distance in the Z-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 5a is not in contact with the substrate CB, 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, when the movement restricting pin 91 abuts against the lower stopper portion 94, the downward movement of the device unit U in the Z direction is restricted. On the other hand, when the iron tip 5a abuts against the substrate CB and the device unit U moves upward in the Z direction, the movement restricting pin 91 abuts against the upper stopper portion 93, and the upward movement of the device unit U in the Z direction is restricted.

[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 includes 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 Z direction, as shown in Fig. 6. For example, as shown in Fig. 6, the wall 11 has a ZX plane.

[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 Z 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 Z direction.

[0048] The sliding guide 13 is fixed near the lower end of the wall 11 in the Z direction. The sliding guide 13 is fixed to the wall 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 the upper cutter blade 21 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 in the Z direction further than the Z-directional upper surface of the cutter lower blade 22, and extend from the Z-directional 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-directional 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 cutter upper blade 21 is disposed between the upper surface of the cutter lower blade 22 and the retaining portions 132. As a result, the cutter upper blade 21 is guided in the X direction and prevented from coming off in the Z 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. 7 , 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 penetrates the lower cutter blade 22 in the Z direction, 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 the gas supply source GS 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 Z-direction 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 in the Z direction. That is, the upper cutter blade 21 slides in the X direction on the Z-direction upper surface of the lower cutter blade 22. The upper cutter blade 21 is slid by the drive mechanism 3.

[0055] The cutter upper 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 cutter upper blade 21 in the Z 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 cutter upper blade 21 in the Z 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 in the Z direction, 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 in the Z direction contacts the upper surface of the cutter upper blade 21, and the upper end of the spring 233 in the Z direction 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 in the Z direction. As a result, the rod portion 231 connected to the head portion 232 is lifted upward in the Z direction, 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 in the Z direction.

[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 in the Z direction. 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 overlapping in the Z direction, 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 Z 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 Z 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 in the Z direction. When the pusher pin 23 protrudes downward in the Z direction from the pin hole 212, a portion of the pusher pin 23 is inserted into the lower blade hole 211. If a solder piece Wh (described below) remains at the entrance of the lower blade hole 211 after the wire solder W has been cut, the tip of the pusher pin 23 will push the solder piece Wh, causing it to fall.

[0063] As shown in FIGS. 6 and 7 , 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 of the air cylinder 31 (here, the lower end in the Z direction). 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 in the Z direction.

[0064] The piston rod 32 passes through a through-hole (not shown) provided in the holding part 12. The piston rod 32 is provided parallel to the 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 in the Z direction. The sliding of the cam member 33 is guided by the guide shaft 35.

[0065] 7, 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] 7 and 8, 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 and Z directions). 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 to be less likely to rattle, the cylindrical portion may be omitted and the support portion 331 may be formed only by the 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 7 and 8, 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 (Z 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 6 and 7, 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. The pair of feed rollers 61 are biased toward each other, and the biasing force sandwiches the wire solder W. 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 heat source 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 22, as shown in FIG. 7. 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 for attaching the iron tip 5a to its axial end, a solder supply hole 422 that penetrates from the center of the bottom of the recess 421 to the opposite side, and a through-hole 423 that connects the inner and outer circumferential surfaces of the recess 421. 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] The iron tip 5a is inserted into a recess 421 of the heater block 42 and is prevented from coming out by a member not shown. The solder hole 51 of the iron tip 5a is connected to a solder supply hole 421 of the heater block 42, and solder pieces Wh are fed from the solder supply hole 421. When the iron tip 5a is inserted into the recess 421 of the heater block 42, the pressure measurement hole 52 of the iron tip 5a connects to a through hole 423 of the recess 421. One end of the pressure measurement pipe 8 is connected to the outer peripheral opening of the through hole 423, and the internal pressure of the solder hole 51 is measured by the pressure measurement unit 75 via the pressure measurement hole 52, the through hole 423, and the pressure measurement pipe 8.

[0078] Heat is transferred from the heater 41 to the iron tip 5a, which melts the solder pieces Wh. Therefore, the iron tip 5a is made of a material with high thermal conductivity, such as ceramics such as silicon carbide or aluminum nitride, or metals such as tungsten. While the iron tip 5a in the device unit U is cylindrical, this is not limiting and a cylindrical tip with a polygonal or elliptical cross section may also be used. Iron tips of different shapes may be prepared to match the shapes of the pin terminals P of the board CB and / or electronic component Ep to be soldered.

[0079] The gas supply unit 7 supplies gas supplied from a gas supply source GS provided outside the equipment unit U to the equipment unit U. By using the inert gas as described above, it is possible to prevent oxidation of the solder. As shown in FIG. 7, the gas supply unit 7 has a pipe 70, a first adjustment unit 71, and a first measurement unit 72. The pipe 70 is a pipe that allows nitrogen gas from the gas supply source GS to flow into the gas inlet hole 222. Note that while the pipe 70 is shown as a line diagram in FIG. 7 for convenience, it is actually a pipe (e.g., a resin pipe) that does not leak nitrogen gas.

[0080] The first adjustment unit 71 includes a flow control valve and adjusts the flow rate of nitrogen gas flowing through the pipe 70. The first measurement unit 72 measures the flow rate of nitrogen gas flowing through the pipe 70. That is, the first measurement unit 72 measures the flow rate of nitrogen gas discharged from the first adjustment unit 71. The first measurement unit 72 then transmits a control signal to the first adjustment unit 71 to control the first adjustment unit 71 so that the measured flow rate of nitrogen gas becomes a predetermined flow rate. That is, the gas supply unit 7 performs feedback control using the first adjustment unit 71 and the first measurement unit 72, and controls the flow rate of nitrogen gas supplied from the gas supply source GS to the solder hole 51 to be constant. Note that an operator may manually operate the first adjustment unit 71 to adjust the flow rate of nitrogen gas based on the measurement results of the first measurement unit 72. Furthermore, if the measured flow rate differs from a predetermined reference value or falls outside a predetermined range due to some abnormality, the control means Cont may issue an alarm indicating that an abnormality has occurred and / or stop the operation of the soldering device.

[0081] One end of a pressure measurement pipe 8 is connected to the outer opening of the pressure measurement hole 52 formed in the soldering iron tip 5a. The other end of the pressure measurement pipe 8 is connected to a pressure measurement unit 75. The pressure measurement unit 75 measures the pressure inside the soldering hole 51 and transmits the measurement result to the control means Cont. As will be described later, the control means Cont determines the state of the soldering iron tip based on the pressure and / or pressure change inside the soldering hole 51. In other words, the control means Cont serves as a state determination unit that determines the state of the soldering iron tip. The control means Cont may also control the soldering apparatus AP based on the determined state of the soldering iron tip. Examples of control of the soldering apparatus AP include moving the apparatus main body A1 toward or away from the board CB, cutting the wire solder W, and heating the soldering iron tip 5a.

[0082] (Soldering device operation) Next, the operation of the soldering apparatus AP will be described. As shown in Fig. 9, the control means Cont (shown in Fig. 5) controls the rotational movement of the articulated arm Am (shown in Fig. 5) of the manipulator ML (shown in Fig. 5) to move the soldering tip 5a of the apparatus main body A1 to a position (apart position) where the central axis of the soldering tip 5a is aligned with and spaced apart upward from the central axis of the pin terminal P protruding from the board CB.

[0083] 10, the control means Cont controls the manipulator ML to move the iron tip 5a downward, bringing the bottom surface of the iron tip 5a into contact with the solder resist SR of the board CB, and positioning the pin terminals P of the electronic component Ep in the solder holes 51 of the iron tip 5a. Heat is transferred to the iron tip 5a from the heater 41 (shown in FIG. 7), and when the iron tip 5a comes into contact with the solder resist SR of the board CB, the lands Ld are heated by heat transfer (preheating), and the pin terminals P of the electronic component Ep are also heated by heat transfer via the solder resist SR, the lands Ld, and the board CB, radiant heat from the iron tip 5a, and convection within the solder holes 51.

[0084] 11, a solder piece Wh cut to a predetermined length from the wire solder W by the cutter unit 2 is supplied to the solder hole 51 of the iron tip 5a. The solder piece Wh falls through the solder hole 51, and the lower end of the solder piece Wh comes into contact with the tip of the pin terminal P, and the upper end of the solder piece Wh comes to rest in contact with the inner circumferential surface of the solder hole 51. As described above, heat is transferred from the heater 41 (shown in FIG. 7) to the iron tip 5a, and the solder piece Wh is heated by heat transfer from the contact portion with the solder hole 51. At the same time, the solder piece Wh is heated by radiation from the inner circumferential surface of the solder hole 51 and by convection within the solder hole 51. When the solder piece Wh is heated to a temperature above the melting point of the flux, the flux melts. When the molten flux comes into contact with the inner wall of the hot iron tip 5a, part of the flux vaporizes, generating fumes. The generated fumes are exhausted to the outside of the iron tip 5a through the exhaust hole 53a.

[0085] 12, when the temperature of the solder piece Wh reaches the melting temperature of the solder, the solder piece Wh melts and becomes molten solder MS, which temporarily remains on the pin terminal P in a state where it cannot become spherical due to the constraints of the inner circumferential surface of the solder hole 51. If the pin terminal P has been heated to a temperature equal to or higher than the melting temperature of the solder, the molten solder MS will flow down without remaining on the pin terminal P.

[0086] When the pin terminal P is heated to a temperature equal to or higher than the melting point of the solder, the molten solder MS flows down into the enlarged diameter portion 510, as shown in Fig. 13. A portion of the molten solder MS further flows down into the through hole Th. A portion of the molten solder MS reaches the lower surface side of the board CB and forms a back fillet.

[0087] 14, the soldering iron tip 5a is then moved upward away from the board CB, whereby the molten solder MS is cooled and solidified by the outside air, forming a conical fillet (and back fillet) of solder between the land Ld and the pin terminal P, soldering the land Ld to the pin terminal P. The soldering apparatus AP repeats this series of operations to sequentially solder the pin terminal P of the electronic component Ep to the land Ld of the board CB.

[0088] (Method for determining the condition of the trowel tip) Next, a method for determining the state of the iron tip based on the pressure inside the solder hole 51 of the iron tip 5a will be described. In the gas supply unit 7 shown in FIG. 7, all of the nitrogen gas that flows into the gas inlet hole 222 flows into the solder hole 51 of the iron tip 5a. For example, the gas inlet hole 222 communicates with the lower blade hole 221, which penetrates the cutter lower blade 22 vertically in the Z direction. When nitrogen gas is being supplied, the nitrogen gas is sealed so that it does not escape from the upper end of the lower blade hole 221 in the Z direction.

[0089] The flow rate of the nitrogen gas flowing through the solder hole 51 of the iron tip 5a is adjusted by adjusting the gas from the gas supply source GS using the first adjustment unit 71. The flow control valve provided in the first adjustment unit 71 continues to flow the nitrogen gas at the set flow rate regardless of the pressure inside the piping. In other words, the gas supply unit 7 controls the flow rate to keep the flow rate constant.

[0090] In the device main body A1, for example, when a solder piece Wh is supplied to a solder hole 51, the solder piece Wh occupies a portion of the cross section perpendicular to the axis of the solder hole 51. As a result, the flow path area of ​​the portion of the solder hole 51 through which nitrogen gas flows becomes smaller, making it difficult for the nitrogen gas to flow, i.e., the flow path resistance increases. When the flow path resistance of the solder hole 51 increases, the pressure P within the solder hole 51 increases. In other words, a change in the state of the soldering iron tip 5a causes the pressure P within the soldering iron hole 51 to fluctuate. The control means Cont determines the state of the soldering iron tip 5a based on this pressure P or a change in the pressure P. For example, the control means Cont pre-stores information correlating changes in the pressure P with the cause of that change. Based on the calculated change in pressure P, the control means Cont determines the cause, i.e., the state of the soldering iron tip 5a.

[0091] The pressure P in the solder hole 51 in each state of the iron tip 5a will be described below with reference to Fig. 15. Fig. 15 is a diagram showing the change in the pressure P in the solder hole 51 when a single soldering operation is performed by the soldering apparatus AP.

[0092] In this embodiment, the soldering tip 5a is in six states: a reference state, a soldering tip contact state, a solder piece input state, a solder piece melted state, a solder piece flowing state, and a soldering tip separated state. The soldering device AP changes to each of these states in sequence during one soldering operation.

[0093] (a) Reference condition As shown in FIG. 9, in the apparatus main body A1, prior to soldering (for example, when the soldering tip 5a is preheated or the substrate CB to be soldered is changed), the soldering tip 5a is separated from the substrate CB. The state in which the soldering tip 5a is separated from the substrate CB is defined as the reference state. That is, the lower end opening of the solder hole 51 is open to the atmosphere. In addition, in this embodiment, when the apparatus main body A1 is in the reference state, the heater unit 4 is driven to heat the soldering tip 5a. In the reference state, when the supply of nitrogen gas from the gas supply source GS begins, the nitrogen gas is supplied to the gas supply unit 7. As described above, the gas supply unit 7 adjusts the nitrogen gas to a flow rate Q using the first adjustment unit 71.

[0094] When the apparatus main body A1 is in the reference state, the lower opening of the solder hole 51 is open to the atmosphere. Therefore, even when nitrogen gas is supplied to the solder hole 51 from the gas supply unit 7, the pressure P inside the solder hole 51 is constant. The pressure P inside the solder hole 51 in the reference state is defined as pressure Pa. In the reference state, the lower opening of the solder hole 51 of the iron tip 5a is open to the atmosphere, so only a small amount of nitrogen gas flows to the outside from the exhaust hole 53a.

[0095] (b) Contact state of the trowel tip 10, the soldering apparatus AP brings the soldering iron tip 5a into contact with the solder resist SR on the board CB after the reference state to perform soldering. When the soldering iron tip 5a comes into contact with the solder resist SR, the lower end opening of the solder hole 51 in the soldering iron tip 5a is partially blocked by the solder resist SR and the land Ld. The nitrogen gas that passes through the solder hole 51 flows out to the outside from the through hole Th into which the pin terminal P is inserted.

[0096] The flow path area of ​​the portion of the through hole Th into which the pin terminal P is inserted, through which the nitrogen gas escapes, is smaller than the cross-sectional area perpendicular to the central axis C1 of the solder hole 51. Therefore, when the iron tip 5a is in contact, the flow path resistance in the solder hole 51 becomes larger than in the reference state, and the pressure Pb of the nitrogen gas in the solder hole 51 in the iron tip contact state becomes higher than the pressure Pa in the reference state.

[0097] (c) Solder piece inserted As shown in FIG. 11 , after the land Ld is heated to an appropriate temperature, a solder piece Wh is introduced into the solder hole 51. The solder piece Wh contacts the pin terminal P inserted into the solder hole 51 and stops inside the solder hole 51. Because the solder piece Wh stops midway through the solder hole 51, the flow path area of ​​the solder hole 51 through which the nitrogen gas passes is reduced. As a result, the flow path resistance within the solder hole 51 is greater in the solder piece introduced state than in the iron tip contact state. The pressure Pc within the solder hole 51 in the solder piece introduced state is higher than the pressure Pb in the iron tip contact state. Furthermore, in the present invention, the opening 54 on the inner peripheral surface of the exhaust hole 53a is formed in the melted region of the solder piece Wh. Therefore, the solder piece Wh partially blocks the opening 54, and the amount of nitrogen gas flowing out of the exhaust hole 53a from the iron tip 5a is the same as or lower than in the iron tip contact state.

[0098] (d) Melted solder piece 12, when the solder piece Wh inserted into the solder hole 51 is heated and melted by the iron tip 5a, the solder hole 51 and the exhaust hole 53a are blocked by the molten solder MS. This prevents nitrogen gas from leaking out from the lower end opening of the solder hole 51 and the exhaust hole 53a. As a result, when the solder piece Wh melts, the pressure Pd of the nitrogen gas inside the solder hole 51 becomes higher than the pressure Pc when the solder piece is inserted.

[0099] As described above, the exhaust holes 53a are inclined upward toward the outside in the radial direction of the iron tip 5a, so that the molten solder MS does not flow out of the iron tip 5a through the exhaust holes 53a.

[0100] (e) Solder piece spill state As shown in FIG. 13, when the molten solder MS flows down from the tip of the pin terminal P, the lower opening of the solder hole 51 is blocked by the molten solder MS that has blocked the land Ld and the through-hole Th. Meanwhile, the exhaust hole 53a is opened. As a result, the nitrogen gas does not flow out from the lower opening of the solder hole 51 to the outside, but is exhausted to the outside of the iron tip 5a through the exhaust hole 53a. Note that the exhaust hole 53a has a smaller inner diameter than the solder hole 51 and therefore has a higher flow resistance. As a result, the pressure Pe of the nitrogen gas inside the solder hole 51 is smaller than the pressure Pd when the solder pieces are molten and greater than the pressure Pc when the solder pieces are inserted. Note that because the iron tip 5a is constantly heated by the heater unit 4, all of the molten solder MS flows out of the iron tip 5a, i.e., to the land Ld and the pin terminal P of the electronic component Ep.

[0101] (f) Iron tip separation state As shown in Figure 14, when soldering between the pin terminal P of the electronic component Ep and the land Ld is completed, the soldering iron tip 5a moves away from the land Ld. In the solder piece outflow state, all or almost all of the molten solder MS flows out of the solder hole 51. As a result, the solder hole 51 returns to the state before soldering, i.e., the same state as the reference state. As a result, the pressure Pf of the nitrogen gas inside the solder hole 51 becomes almost the same as the pressure Pa in the reference state.

[0102] As described above, the pressures Pa to Pe inside the solder hole 51 take different values ​​depending on the state. The control means Cont stores reference values ​​for the pressures Pa to Pe in advance as a database, and can determine the current state of the soldering iron tip by comparing the data on the pressure P inside the solder hole 51 acquired from the pressure measurement unit 75 with these values.

[0103] In addition, if the volume of the solder pieces Wh (molten solder MS) is large and the exhaust hole 53a is blocked by the molten solder MS even in the solder piece outflow state, the pressure Pd inside the solder hole 51 in the solder piece molten state and the pressure Pe inside the solder hole 51 in the solder piece outflow state may be approximately the same. In this case, it becomes difficult to determine the state from the pressure inside the solder hole 51. Therefore, the control means Cont may detect the state of the iron tip by taking into account the change over time in the pressure P inside the solder hole 51. For example, the control means Cont may determine that the iron tip 5a has changed from the solder piece molten state to the solder piece outflow state when a predetermined time has passed since the second measurement unit 75 detected the pressure Pd inside the solder hole 51.

[0104] In the device main body A1, the state of the iron tip 5a changes in the following order: reference state, iron tip contact state, solder piece input state, solder piece melted state, solder piece flowing state, and iron tip separated state. The pressure P in the solder hole 51 in each state is as shown in the graph in Figure 15. Figure 15 shows the change in pressure P in the solder hole 51 when the soldering device AP performs one soldering. In Figure 15, the vertical axis represents pressure P and the horizontal axis represents time. Note that the pressure values ​​Pa, Pb, Pc, Pd, Pe, and Pf shown in Figure 15 are reference values.

[0105] 15, the first region Ar1 is when the iron tip 5a is in the reference state, and in the first region Ar1, the pressure inside the solder hole 51 is pressure Pa. In the second region Ar2, the iron tip is in the iron tip contact state, and when the iron tip changes from the reference state to the iron tip contact state, the pressure suddenly increases from pressure Pa to pressure Pb due to contact of the iron tip 5 with the land Ld.

[0106] In addition, in Figure 15, the third region Ar3 shows the tip of the iron in a state where a solder piece is being introduced, and when a solder piece Wh is introduced into the solder hole 51, part of the flow path of the solder hole 51 and the exhaust hole 53a is blocked, increasing the flow path resistance, and the pressure increases rapidly from Pb to Pc.

[0107] In the fourth region Ar4, the tip 5a of the soldering iron is in a molten solder piece state, and the solder holes 51 and exhaust holes 53a are blocked by the molten solder pieces Wh, increasing the flow path resistance. The solder pieces Wh melt first, with the flux melting relatively slowly, followed by the solder melting rapidly. The pressure initially rises slowly from Pc to Pd, then rises suddenly after a certain period of time. That is, the change from the third region Ar3 to the fourth region Ar4 is initially slow, then rises suddenly.

[0108] In the fifth region Ar5, the tip 5a of the soldering iron is in a solder piece outflow state, and the lower end opening of the solder hole 51 is blocked by molten solder MS, but the exhaust hole 53a is open, so the pressure Pe in the solder piece outflow state is lower than the pressure Pd in ​​the solder piece molten state.

[0109] Then, when the iron tip 5a separates from the land Ld, all or almost all of the molten solder MS has flowed out of the solder hole 51, so the solder hole 51 returns to the state before soldering, i.e., the same state as the reference state, and the pressure Pf of the nitrogen gas inside the solder hole 51 becomes approximately the same as the pressure Pa in the reference state.

[0110] As described above, the pressure P inside the solder hole 51 is characterized not only by its value but also by the rate of change of the pressure P when the state changes (a rapid change or a slow change).

[0111] Whether the soldering process is being performed normally is determined as follows. First, a reference value range for the pressure P inside the solder hole 51 in each soldering state is set in advance. Then, the measured pressure P inside the solder hole 51 is compared with the reference value range for each soldering state to determine whether the soldering process is being performed normally. For example, the determination in the solder piece insertion state will be described. First, an upper limit Px1 and a lower limit Py1 of the reference value are set in the time period Ar3, which is the solder piece insertion state. The upper limit Px1 and the lower limit Py1 are expressed as Px1 = Pc + x1 and Py1 = Pc - y1, respectively (x1 and y1 are positive numbers). Then, when the pressure P inside the solder hole 51 measured during the time period Ar3 in the soldering process deviates from the range between the upper limit Px1 and the lower limit Py1, the control means Cont may issue an alarm or stop operation, indicating that an abnormality has occurred in the soldering process. Note that one of x1 and y1 may be 0.

[0112] Furthermore, the control unit Cont can set a second upper limit value Px2 = Pc + x2 and a second lower limit value Py2 = Pc - y2 using x2 and y2, which are smaller than the aforementioned x1 and y1. If the pressure P in the solder hole 51 measured during the time period Ar3 deviates from the range between the second upper limit value Px2 and the second lower limit value Py2, the control unit Cont can issue a warning to the operator. Note that one of x2 and y2 may be 0. The above description describes a one-stage system in which a warning is issued or operation is stopped using a first upper limit value and a first lower limit value, or a two-stage system in which a warning is issued or operation is stopped using a second upper limit value and a second lower limit value, and a reference value is used to issue a warning or stop operation. However, these are merely examples, and more reference values ​​may be used to issue warnings or warnings in two or more stages. Furthermore, a range of reference values ​​is similarly set for states other than the solder piece insertion state, and the measured branch flow rate is compared with the range of reference values ​​to determine whether the soldering process is proceeding normally.

[0113] Furthermore, regardless of time and pressure, once the solder melts or flows out, the pressure P in the solder hole 51 increases to a maximum value. The control means Cont can also determine that the solder has melted when it detects a value near the peak value of the pressure P in the solder hole 51 (here, pressure Pd).

[0114] (Determining the state of dirt) The control means Cont can store reference values ​​for the pressures Pa to Pe in advance as a database, and can determine the contamination state of the solder hole 51 by comparing the reference values ​​with data on the pressure P inside the solder hole 51 obtained from the pressure measurement unit 75. Alternatively, the control means Cont can store reference time-dependent changes in the pressure of the nitrogen gas inside the solder hole 51 during a series of soldering steps, such as when the iron tip 5 is out of contact with the board CB, when the iron tip 5 is in contact with the board CB, when the solder tip 5 is put into contact with the board CB, when the solder piece Wh is inserted into the iron tip 5, when the solder tip 5 is heated and melted, when the molten solder flows out from the iron tip 5, and when the iron tip 5 is separated from the board CB, as a database, and can determine the contamination state of the solder hole 51 by comparing the reference time-dependent changes in the pressure P inside the solder hole 51 obtained from the pressure measurement unit 75.

[0115] An example will be described in which the contamination state of the solder hole 51 is determined in the third region Ar3, i.e., when a solder piece Wh is introduced into the solder hole 51. FIG. 16 shows a state diagram in which the solder piece Wh is introduced into the solder hole 51. In the initial state in which the solder hole 51 is clean, as shown in FIG. 11, the pressure inside the solder hole 51 is Pc. On the other hand, in a state in which dross or other deposits are attached to the inner peripheral walls of the solder hole 51 or the exhaust hole 53a, as shown in FIG. 16, the flow path area through which the nitrogen gas passes through the solder hole 51 and the exhaust hole 53a is small. When the solder piece Wh is introduced, the flow path area becomes even smaller, and the pressure inside the solder hole 51 becomes a pressure Pc' higher than the initial pressure Pc (dashed line in FIG. 15). The control means Cont stores the pressure Pc in the initial state in advance, and can determine the contamination state of the solder hole by comparing the measured pressure inside the solder hole 51 with the pressure Pc.

[0116] (Determining whether the solder is solid or not) Furthermore, in addition to the above-described changes in the state of the soldering iron tip 5a, it is also possible to determine the soldering state between the land Ld of the circuit board CB and the pin terminal P of the electronic component Ep. For example, as shown in Figure 17(a), when the land Ld and the pin terminal P are soldered properly, the solder will have a cone shape. On the other hand, if the preheating is insufficient, the solder will be in a bulged state (potato solder) as shown in Figure 17(b).

[0117] Therefore, after the control means Cont determines that the solder has melted, it moves the iron tip 5a away from the solder resist SR by a distance G from the initial position where contact between the iron tip 5a and the solder resist SR was detected, and determines the soldering state based on the change in pressure P within the solder hole 51. That is, the iron tip 5a is moved away from the solder resist SR by the distance G and maintained for a predetermined time, and the pressure P within the solder hole 51 is measured. If the soldering has been performed normally, as shown in FIG. 17(a), moving the iron tip 5a away from the solder resist SR by the distance G creates a gap between the conical solder and the inner surface of the solder hole 51 of the iron tip 5, and nitrogen gas within the solder hole 51 flows out through this gap, so that the pressure P within the solder hole 51 suddenly decreases to the same or approximately the same as the pressure Pa.

[0118] 17(b), if a potted solder has formed, even if the soldering iron tip 5a is moved a distance G away from the solder resist SR, the dome-shaped raised solder and the inner circumferential surface of the solder hole 51 of the soldering iron tip 5a will still be in contact, or if there is a gap it will be very small, so the pressure P inside the solder hole 51 will not decrease, or if it does decrease, it will be very small. Therefore, by measuring the change in the pressure P inside the solder hole 51, it is possible to determine the soldering condition.

[0119] The separation distance G between the soldering iron tip 5a and the solder resist SR is a distance at which the solder does not come into contact with the inner circumferential surface of the solder hole 51 when soldering is normal, and the solder comes into contact with the inner circumferential surface of the solder hole 51 when a cold solder is formed. This distance may be determined appropriately based on preliminary experiments, taking into consideration the volume of the supplied solder pieces Wh and the shape of the solder hole 51. The separation distance G is typically in the range of 0.2 mm to 2 mm. There are no particular restrictions on the separation speed of the soldering iron tip 5a when separating the solder resist SR to the distance G, but from the perspective of the measurement accuracy of the pressure P, a range of 0.1 mm / sec to 10 mm / sec is preferable, and a range of 0.2 mm / sec to 2 mm / sec is more preferable. The time for which the soldering iron tip 5a is held at the separation distance G is preferably in the range of 0.1 sec to 2 sec.

[0120] In order to perform such abnormality determination, the control means Cont stores in advance a table showing the time change of the branch flow rate in one soldering operation, as shown in Fig. 15, arranges the branch flow rate data from the pressure measurement unit 75 in chronological order, and determines the state of the soldering iron tip by comparing the behavior and values. By using such a determination method, the state of the soldering iron tip can be determined more accurately.

[0121] In this embodiment, the six states that the device main body A1 can be in when performing soldering are (a) the reference state, (b) the solder tip contact state, (c) the solder piece input state, (d) the solder piece melted state, (e) the solder piece flowing out state, and (f) the solder tip separated state, but other states may also be determined.

[0122] (First Modification) In the above-described embodiment, the thickness and length of the solder piece Wh are constant. However, variations in the feeding of the wire solder W may occur. Furthermore, the shape and size of the solder piece Wh may be intentionally changed depending on the size of the area to be soldered, etc. In such cases, the control means Cont may determine the shape, size, etc. of the solder piece Wh based on the magnitude and behavior of the change in pressure P when the pressure P changes from the pressure Pb in the soldering iron tip contact state. If there is a possibility that solder pieces of different sizes and shapes may be fed, the control means Cont preferably has a database containing a table showing the reference value and / or time change of the pressure P in the solder hole 51 in each state for each solder piece Wh of each size and shape.

[0123] (Second Modification) In the above-described embodiment, the soldering iron tip 5a is in a high-temperature state where it can melt solder. However, due to a malfunction of the heater 41 or other reasons, the soldering iron tip 5a may fall outside the normal temperature range set for melting solder. The degree of expansion and viscosity of the nitrogen gas passing through the soldering iron tip 5a vary depending on the temperature of the soldering iron tip 5a, which increases or decreases the flow resistance and, as a result, the pressure of the nitrogen gas. For example, as the temperature of the soldering iron tip 5a decreases, the volume of the nitrogen gas decreases and its viscosity also decreases, resulting in a decrease in the pressure of the nitrogen gas in the solder hole 51. Taking advantage of this, the control unit Cont stores the pressure Pa when the soldering iron hole 51 is open to the atmosphere, i.e., when the soldering iron tip 5a is in a reference state, and can determine the temperature of the soldering iron tip 5a based on the stored pressure Pa and the measured pressure P.

[0124] Furthermore, if the type of gas supplied changes, such as to a mixture of nitrogen and air or oxygen, the flow path resistance also changes, resulting in a difference in the pressure P inside the solder hole 51. Utilizing this, the control means Cont stores the pressure Pa when the solder hole 51 is open to the atmosphere, i.e., when the iron tip 5a is in a reference state, and can determine whether the gas being supplied is nitrogen gas (the gas that should be supplied) based on the stored pressure Pa and the measured pressure P. This enables the control means Cont to detect, for example, an error in the gas piping connection.

[0125] The operations of the first and second modified examples can be performed, for example, at regular intervals. The regular intervals may be managed, for example, by time or the number of soldering operations. Furthermore, the operations may be performed immediately after the soldering apparatus AP is powered on or at the end of the process. Furthermore, the operations may be performed at random timing.

[0126] The embodiment of the soldering device and soldering method described above is merely an example, and various modifications are possible within the scope that does not impair the effects of the present invention. [Industrial Applicability]

[0127] The soldering iron tip according to the present invention can quickly exhaust fumes generated from molten solder to the outside, prevent the exhausted fumes from hitting electronic components on a circuit board, and prevent molten solder from leaking out through the exhaust hole. [Explanation of symbols]

[0128] AP soldering equipment A1 Device body 4 Heater unit (heat source) 41 Heater 42 heater block 5a, 5b, 5c, 5d, 5e, 5f trowel tip 50 Main body 51 Solder hole 52 Pressure measurement hole 53a, 53b, 53c, 53d Exhaust holes 54 Inner surface opening of exhaust hole 55 Exhaust hole outer surface opening 59 Gas release hole 510 Expanded diameter part 6 Solder feed mechanism 7 Gas supply section 75 Pressure measurement section CB Printed Circuit Board C1 Center axis of the main body of the trowel tip Cont Control means D Melted area of ​​solder piece Ep electronic components GS Gas Supply Source MS molten solder Ld Land P-pin terminal SR solder resist Th through hole Double wire solder Wh solder piece

Claims

1. A soldering iron tip that is detachably attached to a device body having a heat source, A columnar main body; a solder hole that penetrates the main body in the axial direction and through which a solder piece is supplied; an exhaust hole having one end opening to the inner circumferential surface of the solder hole and the other end opening to the outer circumferential surface of the main body; the solder hole has a melting area in which the solder piece melts; an opening on the inner peripheral surface side of the exhaust hole is located in the melted region; The opening of the exhaust hole on the outer peripheral surface side is located above the opening of the exhaust hole on the inner peripheral surface side. A trowel tip characterized by the above.

2. 2. The trowel tip of claim 1, wherein the exhaust hole has a slope.

3. 3. The trowel tip according to claim 2, wherein the angle formed by the inclined portion and the axis of the main body is in the range of 10 degrees to 85 degrees.

4. The iron tip according to any one of claims 1 to 3, a device body to which the iron tip is detachably attached; and The device body includes: a heat source for heating the iron tip; a solder piece supply unit that supplies solder pieces to the solder holes; A soldering device comprising:

5. The device body includes: a gas supply source that supplies gas; a gas supply unit that communicates the gas supply source with the solder hole and supplies gas from the gas supply source to the solder hole; a measuring unit that measures the pressure of the gas flowing in the solder hole; The soldering apparatus of claim 4 further comprising:

6. A method for determining the state of a soldering tip of the soldering apparatus according to claim 5, comprising: The flow rate of the gas flowing through the solder hole is constant, A method for determining the state of an iron tip, characterized in that the pressure of the gas flowing in the solder hole is measured and the measured pressure is compared with a pre-stored reference value or table to determine the state of the iron tip.

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