JP2018069315A - Laser brazing device, and cutting method of brazing wire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction of wire consumption and space-saving in which there is no need of securing a work area to straighten the tip of a brazing wire, and there is no need of preparation of melting the tip of the wire before starting the next laser brazing.SOLUTION: Control means 21 stops, when interruption or stoppage of laser brazing is detected, feeding of a brazing wire 6 by a wire feeding part 5, performs an opening operation of an on-off valve 10 interposed in a compressive gas introduction passage 9 to discharge compressive gas from an end part of a wire delivery part 3, and activates the wire feeding part 5 in such a state to lift and cut off the end part of the brazing wire from an irradiation point S.SELECTED DRAWING: Figure 1

Description

  The present invention uses a laser brazing apparatus and a laser brazing apparatus in which a joint portion of a workpiece is joined by a brazing wire melted by irradiation of laser light, and the brazing wire is cut after the laser brazing is interrupted or stopped. The present invention relates to a method of cutting a brazing wire.

  Laser brazing (laser brazing) is a method for joining workpiece joints without melting the workpiece through a wire (brazing material) melted by laser light. It has been adopted.

  In laser brazing, when the brazing operation is finished, the wire is pulled up and cut by elongation at that time, but the wire is pulled up from the molten pool melted by the thermal energy of the laser beam, so the tip immediately after cutting is still It is in a molten state, and therefore a ball is likely to be formed at the tip due to surface tension. Therefore, a step of adjusting the shape of the tip of the wire is necessary as a preparation for the next brazing operation.

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-106270), before starting a brazing operation, a wire is sent out by a predetermined length from a wire delivery unit, and laser beam is irradiated to melt the wire by its own weight. A technique for adjusting the length of the wire protruding from the delivery portion to a certain length and adjusting the tip shape is disclosed.

  Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2009-297724), a wire cutting area is set in the operation range of the robot arm, and an air nozzle is brought close to the side facing the laser beam across the wire in the area, The wire is blown with laser light. At the same time, a technology is disclosed in which compressed air is blown from the air nozzle to the melted portion, so that the melt formed in the melted portion of the wire is scattered and the melt is prevented from remaining in a ball shape.

JP 2012-106270 A JP 2009-297724 A

  However, in the technique disclosed in Patent Document 1, there is a problem in that the wire consumption is unnecessarily increased because a predetermined length of wire is discarded before the brazing operation is started.

  On the other hand, in the technique disclosed in Patent Document 2, it is necessary to separately secure a fusing area for performing air blowing, and further, a device for conveying the wire sending unit and the laser torch unit to the area is necessary. There is an inconvenience that becomes a large scale.

  In view of the above circumstances, the present invention does not require a dedicated work area, and does not require preparation for fusing the tip of the wire before the start of the next laser brazing, thereby reducing wire consumption. It is another object of the present invention to provide a laser brazing apparatus capable of realizing space saving and a brazing wire cutting method using the laser brazing apparatus.

  A first aspect of the present invention is a wire feeding unit that feeds a brazing wire, a laser torch unit that sets an irradiation point at a joint part of a workpiece, and focuses laser light on the irradiation point, and the wire feeding unit The wire guide portion for inserting the brazing wire fed from the wire, and a wire delivery portion for feeding the end of the brazing wire protruding from the tip of the wire guide portion to the irradiation point, and the irradiation point In the laser brazing apparatus for joining the joint portion of the workpiece by melting the end portion of the brazing wire delivered to the laser beam from the laser torch unit, the compressed gas source for generating compressed gas, and the brazing wire A gas guide passage that opens at the tip of the wire delivery portion from which the end of the wire protrudes, a compressed gas introduction passage that communicates the compressed gas source and the gas guide passage, and the pressure An open / close mechanism that interrupts the flow of the compressed gas interposed in a gas introduction path; irradiation of laser light from the laser torch; feeding of the brazing wire from the wire feed; and opening and closing of the open / close mechanism Control means for controlling, when the interruption or stop of laser brazing is detected, the control means stops feeding the brazing wire by the wire feeding section and opens the opening / closing mechanism. The compressed gas is operated and discharged from the end of the wire feed section through the gas guide passage, and the wire feed section is further operated to pull up the end of the brazing wire from the irradiation point and cut it.

  According to a second aspect of the present invention, in the method for cutting a brazing wire using the laser brazing apparatus, when the control means detects an interruption or stop of laser brazing, the wire feeding unit cuts the brazing wire. The feeding is stopped, the opening / closing mechanism is opened, and the compressed gas is discharged from the end of the wire sending section through the gas guide passage, and in this state, the wire feeding section is operated to perform the brazing The end of the wire is pulled up from the irradiation point and cut.

  According to the present invention, when laser brazing is interrupted or stopped, feeding of the brazing wire is stopped, and the end of the brazing wire is irradiated in a state where the compressed gas is discharged from the end of the wire sending section. Since it was cut off from the point, it is not necessary to secure a dedicated work area for cutting the end of the brazing wire, and before fusing the tip of the wire before starting the next laser brazing Preparation is not required, and wire consumption can be saved and space can be saved.

Schematic configuration diagram of laser brazing equipment 1 is an enlarged cross-sectional view of the main part of FIG. III-III sectional view of Fig. 2 Fig. 2 IV-IV cross section Enlarged sectional view equivalent to Fig. 2 at the end of laser brazing Flow chart showing laser brazing work routine (A) is an enlarged sectional view of the wire feeding section when laser brazing is stopped, and (b) is an enlarged sectional view of the wire feeding section when cutting the wire.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A laser brazing apparatus 1 shown in FIG. 1 has a laser torch part 2 and a wire delivery part 3, both of which are connected to each other via a support bracket 4, and a wrist provided at the tip of an arm of a welding robot (not shown). It is fixed on the shaft. The laser torch unit 2 condenses the laser beam at a preset irradiation point S. The irradiation timing of the laser beam L is controlled by a drive signal from a laser brazing control unit (hereinafter simply referred to as “control unit”) 21 described later.

  The welding robot that supports the laser torch part 2 and the wire delivery part 3 moves the irradiation point S along the joint part Wm of the workpieces W1 and W2 by teaching. The wire delivery part 3 has a contact tip 3a on the tip side. The wire feeding unit 3 is supplied with a brazing wire 6 from a wire feeding unit 5 as a wire feeding unit. The wire feeding unit 5 adjusts the drawing amount and the rewinding amount of the brazing wire 6 from a wire drum (not shown) by forward / reverse operation and stop operation of the motor. This motor is controlled by a drive signal from a control unit 21 to be described later, and the projection length of the brazing wire 6 delivered from the contact tip 3a toward the irradiation point S by the operation of the wire feeding unit 5. Is adjusted.

  As shown in FIG. 2, a guide hole 3b as a wire guide portion for guiding the brazing wire 6 in the distal direction is formed in the contact chip 3a. As shown in FIG. 3, the guide hole 3b is set to have such a diameter that the brazing wire 6 can be guided without causing axial displacement, and the brazing wire 6 is slidably supported on the inner periphery of the guide hole 3b. Has been. A ring-like gas reservoir chamber 3c is formed in the upper inner wall of the guide hole 3b.

  Further, a gas guide passage 3d is formed in a cross shape along the wall surface of the guide hole 3b from the gas reservoir chamber 3c toward the tip, and the gas guide passage 3d is opened at the tip of the contact tip 3a. On the other hand, the guide hole 3e above the gas reservoir chamber 3c is formed to be relatively large with respect to the diameter of the brazing wire 6, and the brazing wire 6e is located with respect to the guide hole 3e immediately above the gas reservoir chamber 3c. Is slidably supported through the seal member 7.

  A pressure feed pump 8 communicates with the gas reservoir chamber 3 c via a compressed gas introduction path 9. Further, an open / close valve 10 as an opening / closing mechanism is interposed in the compressed gas introduction path 9, and an accumulator 11 is communicated between the compressed gas introduction path 9 and the pressure feed pump 8. The accumulator 11 and the pressure pump 8 constitute a compressed gas source that generates compressed gas.

  The on-off valve 10 described above is a normally closed type, and is opened by the ON operation of the electromagnetic solenoid 10a. The opening / closing operation of the opening / closing valve 10 is controlled by a control unit 21 described later. The accumulator 11 accumulates air or inert gas fed from the pressure pump 8, and the accumulated air or inert gas (hereinafter referred to as “compressed gas”) is opened by opening the on-off valve 10. Is discharged into the contact chip 3a through the compressed gas introduction passage 9.

  A control unit 21 as a control means for controlling the electromagnetic solenoid 10a, the wire feeding unit 5 and the laser torch unit 2 of the on-off valve 10 is mainly composed of a well-known microcomputer equipped with a CPU, RAM, ROM and the like. The ROM stores a control program executed by the CPU, fixed data, and the like.

  In the laser brazing operation, the welding robot moves the laser torch unit 2 and the wire delivery unit 3 in accordance with teaching stored in advance, with the irradiation point S aligned with the joint portion Wm of the two workpieces W1 and W2. . At that time, the control unit 21 irradiates the laser beam L from the laser torch unit 2 in synchronization with the movement by the welding robot and drives the wire feeding unit 5 to deliver the brazing wire 6 to the irradiation point S. When the laser brazing feed is interrupted or stopped due to the end of laser brazing, the on-off valve 10 is immediately opened, and the compressed gas accumulated in the accumulator 11 is brazed from the tip of the contact tip 3a. In a state where the tip of the attachment wire 6 is sprayed, the emission of the laser light L from the laser torch unit 2 is stopped. Thereafter, the brazing wire 6 is unwound and the tip is cut.

  Specifically, the laser brazing operation executed by the control unit 21 is processed according to the laser brazing operation routine shown in FIG.

  This routine is started after the welding robot moves the laser torch part 2 and the wire delivery part 3 and the irradiation point S is positioned at the welding start position of the joint part Wm of the workpieces W1, W2.

  In step S1, the wire feeding unit 5 is driven so that the brazing wire 6 protrudes from the tip of the contact tip 3a by a predetermined length with respect to the position of the irradiation point S. Then, the process proceeds to step S2, and the laser torch unit 2 The laser beam L is emitted from the laser beam and condensed at the irradiation point S, and the process proceeds to step S3.

  On the other hand, the welding robot moves the laser torch part 2 and the wire delivery part 3 to move the irradiation point S along the joint part Wm. Then, the brazing wire 6 is melted along the joint portion Wm by the thermal energy of the laser beam L, and the joint portion Wm is sequentially joined through the continuously formed beads.

  In step S3, it is checked whether or not the feeding between the laser torch unit 2 and the wire sending unit 3 by the welding robot is interrupted or stopped. If the feeding is continued, the process returns to step S1 and the laser brazing operation is continued. Let On the other hand, when the feed by the welding robot is interrupted or stopped, the process proceeds to step S4.

  In step S4, the wire feeder 5 is stopped to stop feeding the brazing wire 6 in the direction of the irradiation point S, and the process proceeds to step S5, where an ON signal is sent from the control unit 21 to the electromagnetic solenoid 10a of the on-off valve 10. Is transmitted to open the on-off valve 10 (state shown in FIG. 5).

  Then, the compressed gas accumulated in the accumulator 11 flows into the gas reservoir chamber 3c formed in the contact tip 3a through the compressed gas introduction path 9. Then, from this gas reservoir chamber 3c, it passes through the gas guide passage 3d formed in a cross shape along the guide hole 3b, and is discharged from the lower end of the contact tip 3a to the brazing wire 6 in the distal direction. Along along.

  Next, the process proceeds to step S6, where the wire feeding unit 5 is driven to retract the brazing wire 6 by a predetermined length (state shown in FIG. 7A), and in step S7, laser irradiation from the laser torch unit 2 is stopped ( FIG. 7 (b) state).

  Then, the softened tip of the brazing wire 6 is pulled up from the molten pool P formed by the thermal energy of the laser beam L collected at the irradiation point S, and is cut by elongation at that time. At this time, wind pressure is applied to the tip by blowing compressed gas, and the surface is rapidly cooled and softened by the wind pressure. In general, when the tip of the brazing wire 6 is pulled up and cut from the molten pool P, a ball is formed at the tip by surface tension, but by cooling the tip with compressed gas as in this embodiment, Formation can be prevented.

  As a result, the work for adjusting the tip shape of the brazing wire 6 such as removing balls, which has been conventionally performed as a preparation for the next brazing work, is unnecessary, and not only the work efficiency is improved, Wire consumption can be saved. Further, as shown in FIG. 7B, the wind pressure of the compressed gas is blown from the tip end side of the contact tip 3a against the tip end of the brazing wire 6 which is pulled up and cut by the elongation at that time. Becomes resistance when trying to form a ball.

  Therefore, not only the formation of the ball on the tip of the brazing wire 6 is further obstructed, but also the outer shape of the tip is adjusted by this wind pressure, and the next brazing operation can be executed without any preparation, and the work efficiency Can be further improved.

  When the program proceeds to step S8, the drive signal for the on-off valve 10 is turned off and the routine is exited. When the on-off valve 10 is turned off, as shown in FIG. 2, the supply of compressed gas to the contact tip 3a is cut off, and the next brazing operation is prepared.

  As described above, in this embodiment, when the laser brazing operation is interrupted or stopped, the compressed gas is blown toward the tip of the brazing wire 6 through the contact tip 3a. Even if the tip of the steel plate is pulled up from the molten pool P and cut, no ball is formed on the tip, so that the next laser brazing operation does not require preparations such as fusing the tip, improving work efficiency. Can be planned. Further, when performing the next laser brazing operation, it is not necessary to cut the tip of the brazing wire 6 which has been conventionally prepared as a preparation, and it is possible to realize a reduction in wire consumption.

  Furthermore, in this embodiment, since the compressed gas is blown through the contact tip 3a, even if the tip of the brazing wire 6 is drawn into the contact tip 3a, the guide hole 3b of the contact tip 3a Since the compressed air flows between the outer periphery of the brazing wire 6, welding can be effectively prevented.

  Further, it is not necessary to secure a separate work area for fusing the tip of the brazing wire by air blow as in the prior art. Therefore, it is necessary to provide a device for transporting the wire sending part 3 and the laser torch part 2 to the area. As a result, the entire apparatus can be made compact and the work area can be saved.

  The present invention is not limited to the above-described embodiment. For example, if the laser torch unit 2 and the wire delivery unit 3 move in synchronization, it is not necessary to connect the support bracket 4.

1 ... Laser brazing device,
2 ... Laser torch part,
3 ... wire sending part,
3a ... contact chip,
3b, 3e ... guide holes,
3c: Gas chamber,
3d ... Gas guide passage,
4 Support bracket,
5 ... Wire feeding part,
6 ... brazing wire,
7… Seal part,
8 ... Pressure pump,
9: Compressed gas introduction path,
10 ... open / close valve,
10a: electromagnetic solenoid,
11 ... Accumulator,
21 ... Laser brazing control unit,
L ... Laser light,
P ... molten pool,
S: Irradiation point,
W1, W2 ... Work,
Wm… Seam

Claims (3)

A wire feeding section for feeding a brazing wire;
A laser torch part that sets an irradiation point at the joint part of the workpiece and focuses the laser beam on the irradiation point;
A wire sending section for inserting the brazing wire fed from the wire feeding section, and a wire sending section for feeding the end of the brazing wire protruding from the tip of the wire guide section to the irradiation point; In the laser brazing apparatus for joining the joint portion of the workpiece by melting the end portion of the brazing wire delivered to the irradiation point with the laser light from the laser torch portion,
A compressed gas source for generating compressed gas;
A gas guide passage opening at the tip of the wire delivery section from which the end of the brazing wire protrudes;
A compressed gas introduction path communicating the compressed gas source and the gas guide path;
An opening and closing mechanism that is interposed in the compressed gas introduction path and interrupts the flow of the compressed gas;
A control means for controlling the irradiation of the laser beam from the laser torch unit, the feeding of the brazing wire from the wire feeding unit, and the opening and closing of the opening and closing mechanism;
When the control means detects interruption or stop of laser brazing, the control means stops feeding the brazing wire by the wire feeding section, opens the opening / closing mechanism, and sends the compressed gas to the gas guide passage. The laser brazing apparatus is characterized in that it discharges from the end of the wire feed section via the wire, and further operates the wire feed section to pull up the end of the brazing wire from the irradiation point and cut it. 2. The laser brazing apparatus according to claim 1, wherein the gas guide passage is formed in the wire delivery portion along the wire guide portion. In the cutting method of the brazing wire using the laser brazing apparatus of Claim 1,
When the control means detects the interruption or stop of the laser brazing, the control means stops the feeding of the brazing wire by the wire feeding section, opens the opening / closing mechanism, and sends the compressed gas to the gas guide. The brazing wire is discharged from the end of the wire feeding section through a passage, and the wire feeding section is operated in that state to lift the brazing wire end from the irradiation point and cut it. Cutting method.

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