JP2015131318A - Joining method and joining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably join two metallic members with excellent finish and with an excellent yield by low electric power consumption, without having thermal influence on the periphery.SOLUTION: This joining device comprises: a device body 10 of a unit form incorporated with a DC type power circuit, a control circuit and various driving circuits; a joining head 12 for applying soldering of using an arc to a joining object material (a base material) on an electric part support body S under supply and control of use force from the device body 10; and a gas cylinder 14 being a supply source of shield gas. The joining head 12 is liftably movably provided with a torch 22 on a movable stage 18, and holds a filler material feeder 24 in a predetermined position via a support arm 25 by a support body (unillustrated) independent of a torch stand 20 and the movable stage 18.

Description

  The present invention relates to a joining method and a joining apparatus for joining two metal members.

  An electric circuit consists of a power source that supplies electricity and electric parts that perform a certain function using electricity. Wiring connection or connection work is always required to build an electric circuit. I need it. In general, a large amount of arc welding using an electric discharge phenomenon (arc discharge) is often used for spot joining of discrete terminal members, particularly spot joining of copper bus bars. The arc welding method is a joining method in which the base material is welded using the heat of the arc generated in the air between the electrode and the base material, and the electrode is consumed (melted) by the arc heat (for example, MIG). There are two types: non-consumable electrode type (for example, TIG welding method) that does not wear out.

JP 2011-62723 A

  As described above, the arc welding method is a joining method in which the base metal is welded using the heat of the arc generated in the air between the electrode and the base material. Is also big. In particular, a bus bar, which is an elongated bar-like or plate-like conductor metal used to supply power to a large number of integrated circuits on a circuit board, is mounted on the circuit board and bonded in many places. In view of this, the magnitude of power consumption and the thermal effect on the surroundings when arc welding is used for spot joining between bus bars is a serious problem.

  Also, pure copper is preferably used as the material for the bus bar. Pure copper is roughly classified into two types: oxygen-free copper having a purity of 99.95% or more and tough pitch copper having a purity of 99.9% or less. Tough pitch copper is far more advantageous in terms of cost. However, when arc welding a tough pitch copper bus bar, blow holes are likely to occur. That is, in the case of tough pitch copper, hydrogen reacts with oxygen remaining inside the copper at a high temperature in an arc atmosphere to generate water vapor, and this water vapor becomes a blowhole without being diffused and released to the outside.

  Furthermore, it is a great disadvantage in terms of yield that a metal joint once formed by welding cannot be recovered (recovered) or re-used. For example, if there are 10 bus bar joints or joints on one circuit board and there is poor welding at one of them, even if the welding results at all the remaining nine locations are good, The entire electronic circuit on the circuit board becomes a defective product.

  The present invention solves the problems of the prior art as described above, and a joining method and a joint capable of stably joining two metal members with low power consumption, good finish and high yield without affecting the surroundings. Providing equipment.

  The bonding method of the present invention includes a first step of forming a bonded portion by combining the bonded portions of the first and second metal members, and a second step of bringing the tip of the torch electrode into contact with the bonded portion. And starting to energize between the torch electrode and the bonded portion while supplying a shielding gas around the torch electrode with the tip of the torch electrode in contact with the bonded portion. While continuing the supply of the shielding gas and the energization in step 3, the tip of the torch electrode is separated from the joined portion, and the terminal member is almost melted between the torch electrode and the joined portion. A fourth step of generating a non-arc, supplying a filler material into the arc, melting the filler material with the heat of the arc, and melting the melted material into the gap between the welded portions A fifth step of spreading, and the filler material from the arc. Together is avoided, thereby extinguish the arc, and a sixth step of solidifying the said filler material that has been melted in the gap and its surrounding of the bonding portion.

  The joining device of the present invention is a joining device for joining the parts to be joined of the first and second metal members, the torch body that detachably mounts and holds the torch electrode, the torch electrode, A power source for flowing current in a closed circuit including a bonded portion, and a filler material feeding portion for feeding a filler material toward the bonded portion, and the tip of the torch electrode is While the energization in the closed circuit is started in a state of being in contact with the bonded portion, the tip of the torch electrode is moved away from the bonded portion while the energization in the closed circuit is continued, and the torch electrode and the to-be-bonded portion are An arc that hardly melts the metal member between the joints is generated, the melt material is supplied into the arc, and the melt material is melted by the heat of the arc. Is sufficiently expanded in the gap between the joined parts, and then the filler material It is retracted from said arc, and stops the energization of the said closed circuit.

  In the present invention, an arc is generated between the torch electrode and the welded portion of both metal members, and this arc is used not only for melting the welded portion (arc welding) but for melting the filler material. In addition, since the arc discharge is started by the touch start method, the arc can be generated at a fixed position (a position where the tip of the torch electrode of the bonded portion is in contact). Thereby, in spot joining, it is possible to quickly and surely supply the filler material into the arc and efficiently and stably melt it, and to obtain a high-quality brazed joint with high reliability.

  In particular, in a preferred embodiment of the present invention, a gap between a portion where the torch electrode of the bonded portion is in contact or a position between the tip of the torch electrode and the portion of the torch electrode of the bonded portion is in contact. The filler material is supplied. As a result, the filler metal can be introduced into the arc column or core of the arc without removing the filler material at all times, and the melt material can be melted most efficiently and reliably, and the processing quality of spot welding by brazing is improved. It can be further enhanced.

  In another preferred embodiment, the location where the torch electrode of the bonded portion should contact is set at or near the gap of the bonded portion. As a result, an arc can be generated in or near the gap of the welded portion, and the filler material can be efficiently diffused in the gap.

  In another preferred embodiment, the filler metal is supplied into the arc after a predetermined time (preferably 0.1 to 0.5 seconds) after the arc is generated. Thereby, the influence which a base material receives can be decreased and wettability can be improved.

  In another preferred embodiment, the temperature of the welded portion is monitored, and the arc current of the arc is controlled so that the temperature of the welded portion is higher than the melting point of the filler metal and does not exceed the melting point of the metal member. To do. Preferably, the temperature of the bonded portion is measured using a temperature sensor, and the measured temperature of the bonded portion is higher than the melting point of the filler metal and matches or approximates a predetermined reference temperature lower than the melting point of the metal member. Control the arc current of the arc. By controlling the temperature of the welded part in this way, and thus controlling the temperature at which the filler metal is melted, the efficiency, reliability and reproducibility of brazing performed using the arc heat of the arc are improved. Can do.

  According to the joining method or the joining apparatus of the present invention, by having the above-described configuration, it is possible to stably join two metal members with low power consumption, good finish and high yield without affecting the surroundings. it can.

It is a figure which shows the whole structure of the joining apparatus in one Embodiment of this invention. It is a perspective view which shows the to-be-joined part of the base material in embodiment. It is a flowchart which shows the procedure of the brazing method in embodiment. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the torch raising / lowering operation | movement in the said joining apparatus. It is a figure which shows one step of the melt material supply operation | movement and electricity supply operation | movement in the said joining apparatus. It is a figure which shows one step of the melt material supply operation | movement and electricity supply operation | movement in the said joining apparatus. It is a figure which shows one step of the melt material supply operation | movement and electricity supply operation | movement in the said joining apparatus. It is a figure which shows one step of the melt material supply operation | movement and electricity supply operation | movement in the said joining apparatus. It is a figure which shows one step of the melt material supply operation | movement and electricity supply operation | movement in the said joining apparatus. It is a figure which shows one modification around the rectilinear drive member in embodiment. It is a figure which shows another modification around the rectilinear drive member in embodiment. It is a figure which shows one step of the torch raising / lowering operation | movement and melt material supply operation | movement in one modification. It is a figure which shows one step of the torch raising / lowering operation | movement and melt material supply operation | movement in the said modification. It is a figure which shows one step of the torch raising / lowering operation | movement and melt material supply operation | movement in the said modification.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, the whole structure of the joining apparatus in one Embodiment of this invention is shown. This bonding apparatus has a stationary apparatus configuration that can suitably cope with spot bonding, particularly worship bonding (butt bonding), and is a unit-type apparatus that incorporates a DC power supply circuit, a control circuit, various drive circuits, and the like. Brazing (brazing or brazing or using an arc) on the main body 10 and a material to be joined (base material) on an electric component support (for example, a circuit board or a circuit assembly) S under supply and control of utility from the apparatus main body 10. And a gas cylinder 14 which is a supply source of a shielding gas, for example, argon gas.

  The joining head 12 is provided with a movable stage 18 and a torch stand 20 on a plate-like base 16, and a torch stand 20 mounted on the torch stand 20 so as to be movable up and down, and a support body independent of the torch stand 20 and the movable stage 18 ( The filler material feeding device 24 is held at a predetermined position via a support arm 25 (not shown).

  The movable stage 18 includes an XY stage 26 for moving the electric component support S in the XY direction in the horizontal plane, and a θ stage 27 for moving the electric component support S in the azimuth direction (θ direction) in the horizontal plane. And have. On the other hand, the torch stand 20 is provided with an elevating tower 30 having a built-in elevating drive unit (not shown) using, for example, a servo motor as a drive source on a fixed base 28. A straight drive member 34 is coupled to the lift drive unit of the lift tower 30 via a lift support shaft 32, and the torch 22 is attached to the straight drive member 34 so as to be integrally movable in the vertical direction. A mechanism for connecting the rectilinear drive member 34 and the torch 22 will be described in detail later.

  The torch 22 is fixed in the horizontal direction. The XY stage 26 and the θ stage 27 perform a movement operation in the XY direction and a movement (rotation) operation in the θ direction under the control signal sent from the apparatus main body 10 via the electric cable 36, respectively. It is possible to position the bonded portion WJ of the bonded material to be brazed on the mounted electrical component support S directly below the torch 22.

  The torch 22 is supplied with the power for brazing and the shielding gas SG in the present embodiment from the apparatus main body 10 via the hose 38 with a built-in electric cable, and is a cylindrical torch made of an insulator such as resin. It has a body 40 and a cylindrical or conical torch nozzle 42 attached to the lower end (tip) of the torch body 40, and a pencil-shaped torch electrode (tungsten electrode rod) 44 is placed in the torch body 40 and the torch nozzle 42. It is detachably mounted, and the lower end (tip) of the torch electrode 44 protrudes slightly (usually 2 to 3 mm) from the lower end (tip) of the torch nozzle 42.

  The apparatus main body 10 is provided with a display 46, operation buttons 48, a power switch 50 and the like on the front face of the unit in a touch panel form, and external connection terminals or connectors 52 are provided on the side face or back face of the unit. The shield gas SG sent from the gas cylinder 14 to the hose 15 is supplied to the torch 22 via the apparatus main body 10 and the hose 38.

In FIG. 2, an example of the to-be-joined material (base material) which can apply the spot joining in this embodiment is shown. In the example shown in the figure, for example, two elongated rod-like or plate-like metal members made of copper, for example, bus bars W ₁ and W ₂ are used as base materials, and upper end surfaces of both metal members W ₁ and W ₂ ( The top surfaces of the top surfaces are substantially flush with each other, and the upper ends of the top surfaces are integrated together. The upper ends of the metal members W ₁ and W ₂ combined together form a joined portion WJ. The other end (not shown) of each metal member W ₁ , W ₂ communicates with an electrical component (not shown) mounted on the electrical component support S, for example. Alternatively, one terminal member W ₁ is mounted on an electrical component support S, and the other end of the other terminal member W ₂ is mounted on another electrical component support (not shown). (Not shown).

Further, as shown in FIG. 2, a pair of contacts (contacts) C ₁ and C ₂ are detachably contacted with both metal members W ₁ and W ₂ from both the left and right sides, preferably avoiding the joined portion WJ. These contacts C ₁ and C ₂ are electrically connected to the positive electrode of the power supply circuit 76 (FIG. 5) in the apparatus main body 10 via the electric cable 56.

  Further, a thermocouple 58 is attached as a temperature sensor at or near the bonded portion WJ. The thermocouple 58 is connected to a control unit in the apparatus main body 10 via a thermocouple cable 60 and a temperature measurement circuit (not shown).

  The filler material feeding device 24 operates under a control signal sent from the device body 10 via the electric cable 62 so that the wire-like filler material M can be smoothly fed out. A wound wire reel (not shown), a feed roller (not shown) for feeding the wire melt M from the wire reel at a predetermined speed, and a motor (not shown) for rotationally driving the feed roller (not shown) (Not shown) and the like are provided in the main body 24a, and a cylindrical wire guide 24b for guiding the wire filler metal M to the supply destination is attached to the main body 24a. In this embodiment, the feed roller has a reverse feed function so that the wire-like filler metal M can be withdrawn arbitrarily and instantaneously from the supply destination.

  Further, the filler material feeding device 24 in this embodiment includes a filler material supply amount measuring unit (not shown) for measuring the supply amount of the wire-like filler material M in the apparatus main body 10. Yes. The filler material supply amount measuring unit is attached to, for example, the inside of the main body 24a or the tip of the wire guide 24b, and an encoder (not shown) that detects the amount (length) of the wire-like filler material M delivered. Have The control unit in the apparatus main body 10 receives the output signal of the filler material supply amount measuring unit (encoder), and the supply amount of the wire-like melt material M (the length of the supplied wire) is determined in one spot joining. The rotation operation (rotation speed, rotation time, etc.) of the feed roller is controlled so that the set value is obtained. Thereby, even if the wire-like melt material M sent out from the wire guide 24b bends in the middle, the supply amount (length) of the wire-like melt material M to the workpiece or the joined portion WJ can be controlled to be constant. It has become.

  In this embodiment, as will be described later, the wire-like filler material M can always be introduced and melted into the arc column or core of the arc AC without removing the wire-like filler material M. It can be considered that the entire amount of the wire-like filler metal M sent out toward the joint portion WJ is effectively used for brazing.

As an example, when the base metal members W ₁ and W ₂ are each a bus bar made of a tough pitch copper square bar having a cross section of 2 mm × 2 mm, a tungsten bar having a diameter (φ) of 2.4 mm, for example, is used for the torch electrode 44. For the wire filler metal M, for example, a phosphor copper brazing wire having a diameter (φ) of 0.8 mm is used. In a normal base material, there is always some gap (for example, about 0.1 mm) at the contact interface between the metal members W ₁ and W ₂ . In the brazing of the welded portion WJ in this embodiment, as will be described later, the filler material (phosphorous copper braze) melted by arc heat in the vicinity of the top surface of the welded portion WJ is diffused due to bend and the gap g It is designed to soak inside.

  Next, a mechanism for connecting the straight drive member 34 and the torch 22 in the joining apparatus of this embodiment will be described with reference to FIGS. 4A to 4F. As shown in the drawing, the torch body 40 is passed through the through-hole 34 a of the plate-like rectilinear drive member 34, and the hook-like or flange-like connecting member 66 fixed to the upper part or middle part of the torch body 40 is the rectilinear drive member 34. The torch body 40 is coupled to the rectilinear drive member 34 such that the torch body 40 is placed on the upper surface of the straight drive member 34.

In the torch elevating mechanism having such a configuration, while the lower end of the torch electrode 44 is floating in the air (FIG. 4A), when the elevating tower 30 lowers the rectilinear drive member 34, the connecting member 66 is the upper surface of the rectilinear drive member 34. The torch 22 is moved downward together with the rectilinear drive member 34 in the state of being placed on (Fig. 4B). Then, when the lower end of the torch electrode 44 comes into contact with the upper surface of the joined portion WJ of the base material (W ₁ , W ₂ ) (FIG. 4C) and the rectilinear drive member 34 is further lowered, the connecting portion 66 of the torch body 40 moves straight. Separated from the drive member 34 (FIG. 4D), the torch body 40 stands on the joined portion WJ independently of the rectilinear drive member 34 (FIG. 4D). At this time, the weight of the torch 22 is applied to the bonded portion WJ.

Further, when the straight drive member 34 is moved up to the original height position from the state where the lower end of the torch electrode 44 is in contact with the bonded portion WJ of the base material (W ₁ , W ₂ ) (FIG. 4E), In the middle, the connecting member 66 of the torch body 40 is placed on the rectilinear drive member 34, and the torch body 40 is also moved upward together with the rectilinear drive member 34 (FIG. 4F).

  In this embodiment, the sensor 70 for detecting the connection or separation state between the connection member 66 of the torch body 40 and the rectilinear drive member 34 is provided. The illustrated sensor 70 is composed of a vertical linear scale, and a scale portion 72 extending in the vertical direction attached to the side surface of the connecting member 66, and the scale portion 72 according to the relative height position of the rectilinear drive member 34. And a scale reading unit 74 attached to the linear drive member 34 so as to be optically read at a level. The scale reading unit 74 is composed of a reflective optical sensor, and is electrically connected to a control circuit in the apparatus main body 10 via an electric cable (not shown).

In this sensor 70, as long as the connecting member 66 of the torch body 40 is placed on the rectilinear drive member 34, the output signal of the scale reading unit 74 (even if the rectilinear drive member 34 moves up and down at an arbitrary height position ( (Reading value) is kept constant. However, when the rectilinear drive member 34 is separated from the connecting member 66 of the torch body 40, the relative position between the scale portion 72 and the scale reading portion 74 changes, and the output signal (read value) of the scale reading portion 74 changes. The control unit in the apparatus main body 10 can monitor the relative positional relationship between the rectilinear drive member 34 and the torch body 40 based on the output signal from the scale reading unit 74, and the rectilinear drive member 34 moves forward (downward movement). ), When the lower end of the torch electrode 44 comes into contact with the bonded portion WJ of the base material (W ₁ , W ₂ ), this can be detected. It should be noted that other types of sensors such as proximity sensors may be used instead of the optical sensors using such scales.

  Next, the operation of the bonding apparatus and the brazing method (spot bonding method) in this embodiment will be described with reference to FIGS. 3, 4A to 4F, and 5A to 5E.

First, in the state where the electrical component support S supporting the base material (W ₁ , W ₂ ) of tough pitch copper is placed on the stage 18, the XY stage 26 and the θ stage 27 are as described above. Positioning in the horizontal plane is performed under the control of the internal control unit. By this alignment operation, a preset position on the bonded portion WJ of the base materials (W ₁ , W ₂ ), that is, a position where the lower end of the torch electrode 44 should come into contact for energization start (hereinafter referred to as “energization start”). It is referred to as a “position”.) P is positioned directly below the torch electrode 44. In the case of spot joining as shown in the example (illustration joining), it is preferable to set the energization start position P at the gap g or a location in the vicinity thereof on the top surface of the joined part WJ.

  Usually, since the XY coordinates are assigned to all the joined parts WJ to be joined on the electrical component support S, the alignment operation of the open loop control can be performed. However, it is also possible to perform a feedback control alignment operation using a monitor camera or the like.

When the bonded portion WJ of the base material (W ₁ , W ₂ ) is positioned directly below the torch electrode 44 on the stage 18 as described above, the gap between the filler material feeding device 24 and the bonded portion WJ is determined. But alignment is complete. That is, in between the bonding portion WJ and filler metal feeder 24, the wire guide 24b of the tip or the wire-shaped filler metal M tip preform (W _1, W ₂₎ of the bonding portion WJ The positional relationship is such that the energization start position P is pointed obliquely from above (FIG. 5A).

  Apart from the alignment in the horizontal plane as described above, the start position of the torch 22 is adjusted to an appropriate height position through the elevating tower 30 by the control unit in the apparatus main body 10 also in the height direction. However, when brazing under the same conditions is continuously performed for a plurality of joint portions of the same type, the brazing for the next time is performed by returning the torch 22 to a certain start position after the end of each brazing. The initial height position adjustment can be omitted.

The base material (W ₁ , W ₂ ) on the stage 18 under the control of the control unit in the apparatus main body 10 from the state where the alignment or the initial height position has been adjusted as described above (FIG. 4A). Is soldered with the joining head 12. The flowchart of FIG. 3 shows the procedure of the brazing method (spot bonding method) in this embodiment.

First, the control unit operates the elevating drive unit of the elevating tower 30 to start the downward movement of the rectilinear drive member 34 (step S ₁ ). Since the lower end of the torch electrode 42 is floating in the air (FIG. 4A), when the downward movement of the rectilinear drive member 34 is started, the torch 22 is also rectilinearly driven with the connecting member 66 placed on the upper surface of the rectilinear drive member 34. It moves downward together with the member 34 (FIG. 4B).

Then, when the lower end of the torch electrode 44 comes into contact with the joined portion WJ at the energization start position P (or in the vicinity thereof with a slight deviation) (step S ₂ ), the downward movement of the torch 22 ends there (FIG. 4C). Immediately thereafter, when the rectilinear drive member 34 is separated from the connecting member 66 of the torch body 40 (FIG. 4D), the control unit stops the downward movement of the rectilinear drive member 34 in response to the output signal of the sensor 70 (step S ₃ ). .

  Note that the control unit starts supplying the shield gas SG in the middle of the downward movement of the torch 22 or immediately after the end of the downward movement. The shield gas SG is supplied from the cylinder 14 to the torch 22 via the apparatus main body 10 and the hose 38. The torch 22 introduces the shield gas SG into the upper part of the torch body 40 and ejects the introduced shield gas SG from the opening of the torch nozzle 42 at a predetermined flow rate (for example, 5 liters / minute).

In this way, the control unit starts energization while the lower end of the torch electrode 44 is in contact with the energization start position P (or the vicinity thereof) on the bonded portion WJ (step S ₄ ). That is, the switch SW of the DC power supply circuit 76 composed of a constant current source is switched from the OFF state to the ON state in the apparatus main body 10. Then, the positive electrode of the DC power supply circuit 76 → the switch SW in the ON state → the electric cable 56 → the contacts C ₁ and C ₂ → the joined portion WJ → the torch electrode 44 → the electric cable 39 in the hose 38 → the negative electrode of the DC power supply circuit 76 A constant DC current i flows in the path or the closed circuit 78 (FIG. 5C).

The current value of the direct current i may be kept constant from the start to the end of energization, or may be switched stepwise or continuously in the middle. When maintaining a constant value throughout the energization time, when the arc is generated by separating the lower end of the torch electrode 44 from the welded portion WJ, the wire-shaped filler metal (phosphorous copper brazing) M having a melting point of 640 ° C. is rapidly melting. In addition, the joined portion (tough pitch copper) WJ having a melting point of 1000 ° C. or higher is set to a current value I _M (for example, 70 A) at which arc heat is obtained that does not melt at all or hardly.

Alternatively, at the time of initial energization under this contact state, the current value of the current i may be controlled to a value I _S that is much lower than the value I _M suitable for brazing. That is, in order to extend the life of the torch electrode 42, it is preferable to generate arc discharge as weakly as possible at the moment when the tip of the torch electrode 42 is separated from the bonded portion WJ. On the other hand, in order to improve the wettability of brazing that is started by pulling the tip of the torch electrode 42 away from the bonded portion WJ, an appropriate Joule heat is applied to the bonded portion WJ during energization at this stage (under the contact state). It is preferably generated and preheated. In this embodiment, from these two viewpoints, the current value I _S at the start of energization of the current i flowing in the closed circuit 78 is controlled within a range of 10 to 20 A, for example.

Alternatively, in this embodiment, the temperature of the bonded portion WJ can be monitored through the temperature sensor (thermocouple) 58, so that the control unit supplies the current through the power supply circuit 76 so as to control the monitored temperature to a certain value or a certain range. it is also possible to variably control the initial current value I _S for i.

When the predetermined time T ₁ has elapsed from the start of energization (step S ₅ ), the control unit moves the linear drive member 34 slightly upward to set the lower end of the torch electrode 44 away from the bonded portion WJ (for example, 3 mm). Only upward (step S ₆ ), it is stopped at that height position. At the same time as or after completion of the separation of the torch electrode 44, the control unit controls the power supply circuit 76 to set the current value of the current i flowing in the closed circuit 78 to the initial current value I _S thus far. It switched to the normal current value I _M for further larger brazing than (step S _7).

In this way, the lower end of the torch electrode 44 is separated from the bonded portion WJ, and the current (arc current) i having a normal current value I _M flows in the closed circuit 78, whereby the bonded portion (tough pitch copper) having a melting point of 1000 ° C. or higher. ) An arc AC capable of rapidly melting the wire-like filler metal (phosphorous copper brazing) M having a melting point of 640 ° C. with little or no melting of WJ is generated in the space gap between the torch electrode 44 and the joined portion WJ. In particular, it is generated in a spatial gap between the lower end of the torch electrode 44 and the energization start position P on the bonded portion WJ.

Then, when a predetermined delay time T ₂ elapses after the tip of the torch electrode 42 is separated from the bonded portion WJ or the current value of the current i in the closed circuit 78 is switched to the normal value I _M (step S). ₈ ) At this timing, the control unit starts supplying the wire-shaped filler metal M into the arc AC through the filler material feeding device 24 (step S ₉ ).

This delay time T ₂ is determined in consideration of the optimum time for improving the wettability and the influence on the base material, and is usually selected in the range of 0.1 to 0.5 seconds. In addition, after the delay time T ₂ has elapsed, the operation of the filler material feeding device 24 is started so that the tip of the wire-like filler metal M enters the arc column of the arc AC just in time. The timing may be slightly advanced.

  In this embodiment, since the tip of the wire-like filler material M is sent from obliquely upward toward the energization start position P on the joined portion WJ, the wire-like filler material M is surely connected to the lower end of the arc column of the arc AC. It is introduced into the part and melts quickly by receiving arc heat at the introduction position. Then, the melted filler material <M> spreads to the periphery due to the slack, and penetrates into the gap g of the bonded portion WJ or inside (see FIG. 5D).

The controller monitors the temperature of the welded portion WJ through the temperature sensor (thermocouple) 58 while supplying the wire-like melted material M into the arc AC through the melt material feeding device 24, and The arc current i is controlled so that the temperature of WJ is higher than the melting point of the filler metal M and does not exceed the melting points of the base materials (W ₁ , W ₂ ). More specifically, the measured temperature of the bonded portion WJ is equal to or approximates a predetermined reference temperature (for example, 750 ° C.) that is higher than the melting point of the filler metal M and lower than the melting point of the base materials (W ₁ , W ₂ ). Thus, the current value I _M of the arc current i is controlled. For example, when the measured temperature of the welded portion WJ falls below the reference temperature, the current value I _M of the arc current i is increased to about 100 A, and when the measured temperature of the welded portion WJ exceeds the reference temperature, the arc current i The control for reducing the current value I _M to about 10 A is repeated.

  By controlling the temperature of the welded portion WJ and thus the temperature at which the wire filler metal M is melted, the efficiency, reliability and reproduction of brazing performed using the arc heat of the arc AC are controlled. Can be improved.

When a predetermined time T ₃ (for example, 2 to ₃ seconds) elapses after the supply of the wire-like filler material M is started (step S ₁₀ ), the control unit controls the filler-material feeding device 24 to form a wire shape. The filler metal M is retracted from the arc AC (step S ₁₁ ), and then the switch SW of the power supply circuit 78 is turned off to stop energization (step S ₁₂ ). Immediately after that, the supply of the shielding gas SG is also stopped.

  The control unit replaces the timer function as described above and, based on the output signal of the melt material supply amount detection unit (encoder) of the melt material feeding device 24, the delivery amount of the wire-like melt material M Alternatively, the wire filler metal M can be retracted from the arc AC at the timing when the supply amount reaches the set value.

When the wire-like filler material M is retracted from the arc AC, the supply of the filler material to the welded portion WJ is stopped at that moment. When the energization stops, the arc disappears at that moment. When the arc disappears, the melted (liquid) filler material <M> diffused in and around the gap g of the joint WJ is immediately solidified by natural cooling in the atmosphere and solid metal or alloy [ M]. In this way, brazing welding joints (joints) are formed at the joints WJ of the base materials (W ₁ , W ₂ ).

Thereafter, the control unit moves the straight drive member 34 upward through the lifting drive unit of the lifting tower 30 and returns the torch 22 to the start position (step S ₁₃ ).

As described above, in this embodiment, the shield gas SC is supplied around the torch electrode 44 in a state where the tip of the torch electrode 44 is in contact with the bonded portion WJ of the base material (W ₁ , W ₂ ). However, energization is started between the torch electrode 44 and the bonded portion WJ. Then, while continuing to supply and energize the shield gas SC, the tip of the torch electrode 44 is moved away from the joined portion WJ, and the base material (W ₁ , W ₂ ) is placed between the torch electrode 44 and the joined portion WJ. An arc AC is generated that can quickly melt the filler material M with little or no melting. Then, the wire-like filler material M is supplied into the arc AC with a slight delay, the melt material M is melted by the heat of the arc AC, and the melted melt material <M> is diffused by wetting. Immerse in the gap g of the joint WJ. And after a certain period of time (or when the delivery amount or supply amount of the wire-like filler material M reaches the set value), the filler material M is retracted from the arc AC, and then the arc AC is extinguished, The melted (liquid) filler material <M> diffused around the gap g of the joined portion WJ and the periphery thereof is solidified.

Thus, in this embodiment, the arc AC generated between the torch electrode 44 and the bonded portion WJ of the base material (W ₁ , W ₂ ) is not the melting (arc welding) of the bonded portion WJ. Used exclusively for melting the soluble material M. As a result, a metal joint (joint) by brazing is obtained at the joint WJ. Therefore, for example, even if the base material (W ₁ , W ₂ ) is made of tough pitch copper, a blow hole as found in arc welding does not occur in principle.

  In addition, since the arc AC is generated by the touch start method and the wire-like filler material M is fed toward the position where the tip of the torch electrode 44 of the joined portion WJ is in contact (the energization start position P), The material M can be surely introduced into the arc column or core portion of the arc AC without being removed and can be melted most efficiently.

  Furthermore, the supply amount of the wire-like melt material M (supplied wire) to the welded portion WJ in one spot joining through the melt material supply amount measuring unit (encoder) provided in the melt material feeding device 24. Can always be controlled to the set value, so that the quality, reliability and reproducibility of brazing process can be improved by combining the above-mentioned effects that the filler metal M can be surely introduced into the arc column of the arc AC. It can be greatly improved.

Furthermore, metal bonding formed by brazing is advantageous in terms of yield because it is easy to recover (recover) or redo even if the bonding is defective. Compared with arc welding, the arc heat generated between the torch electrode and the base metal is much weaker, that is, the arc current is much smaller (about 1/2). It has little effect and can save power consumption.

[Other Embodiments or Modifications]

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above does not limit this invention. Those skilled in the art can make various modifications and changes in specific embodiments without departing from the technical idea and technical scope of the present invention.

For example, in the above-described embodiment, when the linear drive member 34 is further lowered after the lower end of the torch electrode 44 comes into contact with the upper surface of the bonded portion WJ of the base material (W ₁ , W ₂ ), the bonded portion WJ The weight of the torch 22 was added. As another example (modification), as shown in FIG. 6, between the rectilinear drive member 34 and a part of the torch body 40 (for example, a hook-shaped spring receiving portion 80 fixed to the torch body 40), It is also possible to provide a spring member that can be elastically deformed in the direction in which the linear drive member 34 moves, such as a coil spring 82. In this case, by using a compression coil spring for the coil spring 82, the load received by the bonded portion WJ when the torch electrode 42 comes into contact with the bonded WJ can be arbitrarily reduced from the own weight of the torch body 40. This is an advantageous form when the base material (W ₁ , W ₂ ) is a terminal member of a small precision electronic component. Alternatively, by using a tension coil spring as the coil spring 82, the load received by the welded portion WJ when the torch electrode 42 contacts the welded portion WJ can be arbitrarily increased from the own weight of the torch body 40. In addition, the spring force of the coil spring 82 can also be adjusted by providing a mechanism (not shown) for adjusting the position of the spring receiving portion 80.

  In the configuration in which the torch body 40 is attached to the rectilinear drive member 34 via the coil spring 82 in this way, the rectilinear drive member 34 may be linearly moved in an oblique direction or a horizontal direction, and the torch electrode 42 may be linearly moved in the same direction. Is possible.

  The plate-like form of the rectilinear drive member 34 in the above-described embodiment is an example, and the rectilinear drive member 34 can take the structure of a plate, a block, a cylinder, and a housing having an arbitrary shape. Similarly, the connecting member 66 can take any form.

  In the above-described embodiment, the torch 22 is directly attached to the rectilinear drive member 34. However, as shown in FIG. 7, a rectilinear movable member 88 such as an elevating rod is attached to the rectilinear drive member 34 so as to be integrally movable and separable in the vertical direction, and a torch is attached to a holder 90 coupled to the rectilinear movable member 88. The structure which attaches 22 so that attachment or detachment is possible is also possible.

Further, in the above-described embodiment, worship joining is performed in which the tip portions of the _two metal members W ₁ and W ₂ are joined together by brazing. However, although not shown in the drawing, butt joining in which the tips or side surfaces of the _two metal members W ₁ and W ₂ are brought into contact with each other by brazing is also possible.

Further, as shown in FIGS. 8A to 8C, superposition joining is possible in which the two metal members W ₁ and W ₂ are superposed and brazed. In this case, a taper-shaped opening 92 is preferably formed in the upper metal member W ₁ that overlaps at the position of the welded portion WJ, and the lower metal member W ₂ exposed in the opening 92 is formed. Is set to the energization start position P. Then, as in the above embodiment, energization is started with the tip of the torch electrode 44 in contact with the lower metal member W ₂ at the energization start position P (or in the vicinity thereof) (FIG. 8A), and then the torch The tip of the electrode 44 is pulled away to generate an arc AC that emits arc heat having the same strength as described above, and a wire-like filler metal M is supplied into the arc AC (FIG. 8B). Also in this case, it is preferable to send the wire-like filler material M aiming at the energization start position P. As a result, the metal members W ₁ and W ₂ are not melted at all or almost, and only the filler material M is rapidly melted, and the melted filler material <M> is diffused by wetting and the gap g between the metal members W ₁ and W ₂ . Immerse in. Then, when the wire-like filler metal M is withdrawn after a certain period of time has passed, and immediately after the energization is stopped and the arc AC is extinguished, the molten state (liquid) melted in the opening 92 and the gap g is melted. The material M is immediately solidified to become a solid metal or alloy [M] (FIG. 8C).

  In addition, when supplying the wire-like melt material M in the arc AC, it is most preferable to send the melt material M aiming at the energization start position P on the welded portion WJ. However, it is also possible to send the filler material M directly over the energization start position P, that is, through the gap between the tip of the torch electrode 44 and the energization start position P. The shape of the filler material M is arbitrary, and is not limited to a wire, but may be, for example, a rod or a plate.

  Although the joining apparatus in the above embodiment is a stationary type, a form mounted on a robot is also possible. In that case, the linear drive member 34 or the lifting support shaft 32 may be coupled to the robot arm. Similarly, the filler material feeding device 24 may be mounted on the same robot together with the torch 22 or may be mounted on another robot.

  The bonding apparatus in the embodiment includes the automatic alignment mechanism (XY stage 25, θ stage 26) on the stage 18 of the bonding head 12. However, the stage 18 can be configured as a manually movable stage, or the workpiece or the electrical component support S can be manually positioned on the fixed stage 18.

In the joined portion WJ, the material of the metal members W ₁ and W ₂ is not limited to copper or a copper alloy, and may be a conductor such as aluminum, aluminum alloy, or brass, and the material and terminals of the terminal member W ₁ the material of the member W ₂ may be different. Further, the shape of the metal members W ₁ and W ₂ may be arbitrary, and for example, the metal member W ₁ or W ₂ is not limited to a rod or plate having a rectangular cross section, and may be a rod or plate having a circular cross section.

DESCRIPTION OF SYMBOLS 10 Apparatus main body 12 Joining head 18 Movable stage 22 Torch 24 Filler material feeding apparatus 30 Lifting tower 34 Straight drive member 40 Torch body 44 Torch electrode 66 Connecting member

Claims (12)

A first step of forming a joined portion by combining the first and second metal members;
A second step of bringing the tip of the torch electrode into contact with the joined portion;
Under a state in which the tip of the torch electrode is in contact with the joined portion, a third gas starts energization between the torch electrode and the joined portion while supplying a shielding gas around the torch electrode. Process,
While continuing the supply of the shielding gas and the energization, the tip of the torch electrode is moved away from the joined portion, and the first and second metal members are completely placed between the torch electrode and the joined portion. Or a fourth step of generating an arc that hardly melts;
A fifth step of supplying a filler material into the arc, melting the filler material with the heat of the arc, and expanding the melted melt material into the gaps of the joined portions;
And a sixth step of retracting the filler material from the arc and extinguishing the arc to solidify the melted material melted around and around the gap of the welded portion.   The joining method according to claim 1, wherein the filler material is supplied to a place where the torch electrode of the joined portion is in contact.   The joining method according to claim 1, wherein the filler material is supplied over a gap between a tip of the torch electrode and a portion of the joined portion where the torch electrode is in contact.   The joining method according to any one of claims 1 to 3, wherein a place where the torch electrode of the joined portion is to be contacted is set at or near a gap of the joined portion.   The joining method according to any one of claims 1 to 4, wherein the filler material is put into the arc after a delay of 0.1 to 0.5 seconds from the occurrence of the arc.   The temperature of the bonded portion is monitored, and the arc current of the arc is controlled so that the temperature of the bonded portion is higher than the melting point of the filler metal and does not exceed the melting point of the metal member. The joining method according to any one of 1 to 5.   A temperature sensor is used to measure the temperature of the bonded portion so that the measured temperature of the bonded portion matches or approximates a predetermined reference temperature that is higher than the melting point of the filler material and lower than the melting point of the metal member. The joining method according to claim 6, wherein an arc current of the arc is controlled. A joining device for joining the joined parts of the first and second metal members,
A torch body that detachably attaches and holds a torch electrode; and
A power source for flowing current in a closed circuit including the torch electrode and the bonded portion;
A filler material feeding part for feeding a wire-like or rod-like filler material toward the joined part, and
In a state where the tip of the torch electrode is in contact with the bonded portion, energization in the closed circuit is started,
While continuing energization in the closed circuit, the tip of the torch electrode is separated from the bonded portion, and an arc that hardly melts the metal member between the torch electrode and the bonded portion is generated, and Supplying the filler material into the arc and melting the filler material by the heat of the arc;
After the melted melt material has sufficiently expanded in the gap between the welded parts, retract the melt material from the arc and stop energization in the closed circuit;
Joining device.   A temperature sensor for detecting a temperature of the bonded portion, and a predetermined reference in which a temperature of the bonded portion detected by the temperature sensor is higher than a melting point of the filler material and lower than a melting point of the metal member; The joining apparatus according to claim 8, wherein an arc current of the arc is controlled through the power source so as to match or approximate a temperature. A linear drive member that supports the torch body and is capable of linearly moving parallel to the axial direction of the torch electrode;
A first position for moving the torch electrode away from the bonded portion, a second position for bringing the tip of the torch electrode into contact with the bonded portion, and a tip of the torch electrode suitable for arc generation Moving the rectilinear drive member linearly between a predetermined position and a third position for separating from the joined portion;
The joining device according to claim 8 or 9.   The spring drive member provided between the rectilinear drive member and the torch body or a first rectilinear movable member coupled to the torch body and elastically deformable in a moving direction of the rectilinear drive member. Welding equipment.   The position sensor which detects that the front-end | tip of the said torch electrode contacted the said to-be-joined part, and stops the movement of the said linear drive member in response to the output signal of the said position sensor. The joining apparatus as described in.

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