JP2020015081A - Handy laser welding machine and laser welding method - Google Patents

Abstract

To stabilize quality of a weld zone of a work-piece irrespective of operator mastery degree while achieving enlargement of a utilization range of laser welding with use of a handy welding torch.SOLUTION: A handy welding torch 12 radiates a pulse laser beam toward a scheduled joint part L of work-pieces W1, W2. A fiber laser oscillator 24 which outputs the pulse laser beam is optically connected to the handy welding torch 12. A laser control part 30 controls the fiber laser oscillator 24 on the basis of a processing program. A movement speed acquisition part 32 acquires a movement speed of the handy welding torch 12 by estimation. A processing condition renewal part 34 updates a repetitive frequency of the pulse laser beam on the basis of the movement speed of the handy welding torch 12 so that an overlapping ratio of spot S of the pulse laser beam becomes a prescribed overlapping ratio.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a handy laser welding machine and a laser welding method for laser welding two workpieces along a portion to be joined by irradiation of a pulse laser beam.

  2. Description of the Related Art Conventionally, handy laser welding machines having a simpler configuration than automatic laser welding machines such as welding robots have been widely used. A handy laser welding machine is a handy welding torch for irradiating a pulse laser beam toward a joint (scheduled joint) between two workpieces, and a laser oscillator optically connected to the handy welding torch and outputting a pulse laser beam. (See Patent Document 1).

  Therefore, while the handheld welding torch is moved by a manual operation of the operator in the direction along the joint of the two workpieces, the laser oscillator is controlled based on the machining program, and the joint of the two workpieces from the handy welding torch is controlled. Is irradiated with pulsed laser light. Thereby, the two workpieces can be laser-welded along the planned joining portion, and a continuous welded portion (weld bead portion) can be formed on the two workpieces at a portion corresponding to the planned joining portion. Here, the quality of the welded portion of the work can be stabilized by moving the handy welding torch at a constant moving speed according to the processing conditions set in the processing program.

  As prior art related to the present invention, there is a technique disclosed in Patent Document 2 in addition to Patent Document 1.

Japanese Patent No. 4241962 JP-A-2000-24787

  However, moving the handy welding torch at a constant moving speed according to the processing conditions requires skill of an operator, and the quality of the welded portion of the work varies depending on the skill of the operator. Further, it is conceivable to move the handy welding torch at a constant moving speed according to the processing conditions by the automatic feeder disclosed in Patent Document 2. In this case, in order to secure the work pace of the automatic feeder on the work, The shape of the work is limited, and the range of use of laser welding using a handy welding torch is limited.

  In other words, there is a problem that it is not easy to stabilize the quality of the welded portion of the work regardless of the skill level of the operator while expanding the use range of the laser welding using the handy welding torch.

  Therefore, an object of the present invention is to provide a handy laser welding machine and a laser welding method having a novel configuration capable of suppressing variation in the overlapping rate of a spot of a pulse laser beam even when the moving speed of a handy welding torch changes. .

  A handy laser welding machine according to a first embodiment of the present invention includes: a handy welding torch for irradiating a pulse laser beam toward a joining portion (scheduled welding portion) of two works (metal plates); and a handy welding torch. A laser oscillator that is optically connected and outputs pulsed laser light, a laser control unit that controls the laser oscillator based on a processing program, and a moving speed obtaining unit that obtains a moving speed of the handy welding torch, The pulse laser beam among the processing conditions set in the processing program is set so that the overlap rate of the spot of the pulse laser beam becomes a predetermined overlap rate (set overlap rate) based on the moving speed of the handy welding torch. A processing condition updating unit (processing condition adjusting unit) for updating (adjusting) the repetition frequency of light.

  According to a first embodiment of the present invention, the vehicle further includes an acceleration sensor for detecting an acceleration of the handy welding torch, and the moving speed acquiring unit estimates a moving speed of the handy welding torch based on a detection result from the acceleration sensor. May be obtained.

  According to the first embodiment of the present invention, while moving the handy welding torch, the laser control unit controls a laser oscillator based on the processing program, so that the handheld welding torch is connected to a portion where two workpieces are to be joined from the handy welding torch. The pulsed laser light is irradiated toward it. This makes it possible to form a continuous welded portion (joined portion) at a portion corresponding to the portion where the two works are to be joined by laser welding the two works along the portion to be joined.

  When the two workpieces are laser-welded, the moving speed obtaining unit obtains a moving speed of the handy welding torch. Further, the processing condition updating unit is configured to repeat the pulse laser light among the processing conditions based on the acquired moving speed of the handy welding torch so that the overlap rate of the spot of the pulse laser light becomes a predetermined overlap rate. Update frequency. Thereby, even if the moving speed of the handy welding torch changes, it is possible to suppress the variation in the overlapping ratio of the spot of the pulsed laser beam, in other words, the overlapping ratio of the molten pool in the welded portion of the work.

  The laser welding method according to the second embodiment of the present invention comprises controlling a laser oscillator based on a processing program while moving a handy welding torch, and irradiating a pulse laser beam from the handy welding torch. When the workpiece is laser-welded along the planned joining position (planned welding line), the moving speed of the handy welding torch is acquired, and based on the acquired moving speed of the handy welding torch, the spot of the pulsed laser beam is obtained. Updating the repetition frequency of the pulse laser light among the processing conditions set in the processing program so that the overlap rate becomes a predetermined overlap rate.

  In a second embodiment of the present invention, the acceleration of the handy welding torch may be detected, and the moving speed of the handy welding torch may be obtained by estimation based on the detected acceleration of the handy welding torch.

  According to the second embodiment of the present invention, even if the moving speed of the handy welding torch changes, it is possible to suppress the variation in the overlap rate of the spot of the pulsed laser beam, in other words, the overlap rate of the molten pool in the welded portion of the work. Can be.

  According to the present invention, it is possible to stabilize the quality of the welded portion of the work regardless of the skill level of the operator while expanding the range of use of laser welding using the handy welding torch.

FIG. 1 is a schematic perspective view showing a state of laser welding using a handy torch according to an embodiment of the present invention. FIG. 2 is a schematic front view showing the handy laser welding machine according to the embodiment of the present invention. FIG. 3 is a diagram showing a control block of the handy laser welding machine according to the embodiment of the present invention. FIG. 4A is a diagram showing the relationship between the output of the pulse laser and time, and FIG. 4B is an enlarged view of the IVB portion in FIG. 4A. FIG. 5 is a diagram illustrating the overlap ratio of the spots of the pulsed laser light. FIG. 6 is a flowchart illustrating a welding method according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the specification of the present application, “provided” is intended to include not only being provided directly but also being provided indirectly via another member.

  As shown in FIGS. 1 and 2, a handy laser welding machine 10 according to an embodiment of the present invention connects two workpieces (metal plates) W1 and W2 to a line-shaped scheduled joining portion (scheduled welding) by irradiation of a pulsed laser beam. Location) Laser welding along L. The handy laser welding machine 10 forms a continuous welded portion (weld bead) at a portion corresponding to the portion L to be joined between the works W1 and W2. The specific configuration of the handy laser welding machine 10 is as follows.

  The handy laser welding machine 10 includes a handy welding torch 12 that can be held by an operator's hand H. The handy welding torch 12 emits pulsed laser light toward the joint L of the works W1 and W2 while moving in a direction along the joint L of the works W1 and W2 by a manual operation (moving operation) by an operator. I do. Further, the handy welding torch 12 has a hollow welding torch main body 14, and an optical system (not shown) for condensing pulse laser light is provided inside the welding torch main body 14. A nozzle 16 for irradiating a pulse laser beam is detachably provided at the tip of the welding torch main body 14. The nozzle 16 is made of a conductive material such as conductive carbon, and the front end face 16f of the nozzle 16 can come into contact with a portion L to be joined between the works W1 and W2. Further, an acceleration sensor 18 for detecting the acceleration A of the handy welding torch 12 is provided at an appropriate position of the welding torch main body 14.

  The handy laser welding machine 10 includes, as an accessory, a guide plate 20 that guides the handy welding torch 12 in a direction along a portion L to be joined between the works W1 and W2. The guide plate 20 has a support surface 20f that supports the welding torch main body 14. In addition, the shape (plan view shape) of the support surface 20f of the guide plate 20 can be appropriately changed according to the shape of the portion L to be joined between the works W1 and W2.

  The handy laser welding machine 10 includes a device housing 22, and a fiber laser oscillator 24 that outputs (oscillates) pulsed laser light is provided inside the device housing 22. The fiber laser oscillator 24 is optically connected to the handy welding torch 12 via an optical fiber 26. Note that a laser oscillator such as a YAG laser oscillator, a CO2 laser oscillator, or a semiconductor laser oscillator may be used instead of the fiber laser oscillator 24.

  As shown in FIGS. 2 and 3, a control device 28 that controls the fiber laser oscillator 24 and the like based on a processing program (welding program) is provided inside the device housing 22. Further, the control device 28 is configured by one or a plurality of computers, and the acceleration sensor 18 and the like are connected to the control device 28. The control device 28 has a memory (not shown) for storing a machining program and the like, and a CPU (not shown) for interpreting and executing the machining program and the like.

  The control device 28 has a function as a laser control unit 30, a function as a moving speed acquisition unit 32, and a function as a processing condition update unit 34. The specific contents of the laser control unit 30, the moving speed acquisition unit 32, and the processing condition update unit 34 are as follows.

  As shown in FIGS. 2 to 4A and 4B, the laser control unit 30 controls the fiber laser oscillator 24 based on a processing program. In other words, the laser control unit 30 controls the fiber laser oscillator 24 based on processing conditions (welding conditions) set in the processing program. Here, the processing conditions include the peak output (unit: W), pulse width (unit: ms), and repetition frequency (unit: Hz) of the pulsed laser light. The repetition frequency is the number of pulses of the pulsed laser light per second (see FIGS. 4A and 4B).

  The laser control unit 30 allows the fiber laser oscillator 24 to output pulsed laser light when the scheduled portion L of the workpieces W1 and W2 and the nozzle 16 are in a conductive state (conductive state) due to contact. The laser control unit 30 prohibits the fiber laser oscillator 24 from outputting pulsed laser light when the scheduled portion L of the workpieces W1 and W2 and the nozzle 16 are in a non-conductive state (non-conductive state) due to non-contact. .

  The moving speed acquisition unit 32 estimates and acquires the moving speed of the handy welding torch 12 based on the acceleration of the handy welding torch 12 as a detection result from the acceleration sensor 18. Specifically, the moving speed obtaining unit 32 obtains the moving speed of the handy welding torch 12 by estimating (calculating) based on the following relational expression (1).

Vn = Vn-1 + An.times. (Tn-Tn-1) (1)
Here, Vn is the moving speed (unit: mm / sec) of the handy welding torch 12 at the time Tn (unit: sec), and the moving speed Vn-1 is the handy welding torch at the time Tn-1. 12 is the moving speed. An is the acceleration (unit: mm / sec2) of the handy welding torch 12 at the time Tn. Here, n is an integer, and V0 = 0 mm / sec, T0 = 0 sec, and A0 = 0 mm / sec2.

  As shown in FIGS. 2 to 5, the processing condition updating unit 34 sets the overlapping ratio of the spots S of the pulsed laser beam to a predetermined overlapping ratio based on the acquired moving speed of the handy welding torch 12. The repetition frequency of the pulse laser light in the processing conditions is updated (adjusted). Specifically, the processing condition update unit 34 calculates the repetition frequency of the pulse laser beam based on the following relational expression (2), and reflects the calculation result in the processing condition.

fn = Vn / (d × (1-k)) (2)
Here, fn is the repetition frequency (unit: Hz) of the pulse laser light at the time Tn, d is the spot diameter of the pulse laser light, and is the diameter of the weld pool of the welded portion B of the works W1 and W2. Equivalent to. The predetermined overlap ratio is a ratio of the spot diameter d of the pulse laser light to the length r of the overlap portion of the spot S of the pulse laser light, and the predetermined overlap ratio is appropriately changed according to a welding mode or the like. It is possible (see FIG. 5).

  The laser control unit 30 controls the fiber laser oscillator 24 based on the processing conditions including the updated repetition frequency of the pulse laser light. In other words, the laser control unit 30 controls the fiber laser oscillator 24 so that the overlapping rate of the spots S of the pulsed laser light becomes a predetermined overlapping rate.

  Subsequently, the operation of the embodiment of the present invention including the laser welding method according to the embodiment of the present invention will be described. Here, the laser welding method according to the embodiment of the present invention is a method of laser-welding two works W1 and W2 along a scheduled joining position L by irradiation of a pulsed laser beam. A laser welding method according to an embodiment of the present invention includes an acceleration detecting step, a moving speed obtaining step, and a processing condition updating step (processing condition adjusting step).

  As shown in FIG. 1, FIG. 3, and FIG. 6, the tip surface 16f of the nozzle 16 is brought into contact with the start end of the scheduled portion L of the workpieces W1 and W2 by the manual operation of the operator, and the welding torch main body 14 is moved to the guide plate 20 (step S101 in FIG. 6). Then, the handy welding torch 12 is moved by a manual operation of an operator in a direction along the joining scheduled portion L of the works W1 and W2 (step S102 in FIG. 6). At the same time, the laser control unit 30 controls the fiber laser oscillator 24 based on the processing program to irradiate the pulse laser beam from the nozzle 16 to the joint L of the workpieces W1 and W2. Thereby, the two workpieces W1 and W2 are laser-welded along the planned joining portion L, and a continuous welded portion (joined portion) B is formed at a portion corresponding to the planned joining portion L of the works W1 and W2. it can.

  When laser welding the two works W1 and W2, the acceleration sensor 18 detects the acceleration of the handy welding torch 12 (Step S103 in FIG. 6, an acceleration detection step). Next, the moving speed acquiring unit 32 estimates and acquires the moving speed of the handy welding torch 12 based on the detection result from the acceleration sensor 18 (Step S104 in FIG. 6, a moving speed acquiring step). Further, the processing condition updating unit 34 determines the processing conditions set in the processing program based on the acquired moving speed of the handy welding torch 12 so that the overlapping rate of the spots S of the pulsed laser light becomes a predetermined overlapping rate. The repetition frequency of the pulse laser beam is updated (step S105 in FIG. 6, processing condition updating step).

  Then, when the distal end face 16f of the nozzle 16 reaches the end of the scheduled portion L of the workpieces W1 and W2 (Yes in Step S106 in FIG. 6), the laser welding using the handy welding torch 12 ends. On the other hand, if the distal end face 16f of the nozzle 16 has not reached the end of the scheduled portion L of the workpieces W1 and W2 (No in step S106 in FIG. 6), the control device 28 performs the process in step S102 in FIG. Return to

  As described above, when the two workpieces W1 and W2 are laser-welded, the moving speed obtaining unit 32 obtains the moving speed of the handy welding torch 12, and the overlapping rate of the spot S of the pulsed laser beam becomes a predetermined overlapping rate. Thus, the processing condition updating unit 34 updates the repetition frequency of the pulse laser light in the processing conditions. Thereby, even if the moving speed of the handy welding torch 12 changes, it is possible to suppress the variation in the overlap ratio of the spots S of the pulsed laser light, in other words, the overlap ratio of the weld pools of the welds B of the works W1 and W2. .

  Therefore, according to the embodiment of the present invention, the welding unevenness of the welded portion B of the workpieces W1 and W2 is reduced regardless of the skill level of the worker while expanding the range of use of the laser welding using the handy welding torch 12. It is possible to stabilize the quality of the welded portions B of the workpieces W1 and W2 while suppressing.

  The present invention is not limited to the description of the above-described embodiment, but can be implemented in various modes as follows.

  FIG. 1 shows how butt welding is performed as a welding mode of laser welding. The welding mode of laser welding is from butt welding to fillet welding, lap joint welding, groove welding, corner joint welding, or lap welding. It may be changed to welding or the like. The control device 28 includes a laser control unit 30, a moving speed obtaining unit 32, and a processing condition updating unit 34 by executing a processing program, and functions as the laser control unit 30 and the function as the moving speed obtaining unit 32. , And hardware for executing the function as the processing condition updating unit 34.

  Instead of acquiring the moving speed of the handy welding torch 12 by estimation based on the detection result from the acceleration sensor 18, the rotation sensor detects the rotational speed of the rotor that rotates following the movement of the handy welding torch 12, The moving speed of the handy welding torch 12 may be obtained by estimation based on the detection result of the rotation sensor. Further, a plurality of contact sensors for detecting the presence or absence of contact with the nozzle 16 on the support surface 20f of the guide plate 20 are provided at intervals in the longitudinal direction of the guide plate 20, and handy based on the detection results from the plurality of seeding sensors. The moving speed of the welding torch 12 may be obtained by estimation. Furthermore, the image of the handy welding torch 12 and the planned joining position L of the workpieces W1 and W2 may be imaged by the image sensor, and the moving speed of the handy welding torch 12 may be obtained by estimation based on the imaging result from the image sensor.

  The scope of rights included in the present invention is not limited to the above-described embodiment.

DESCRIPTION OF SYMBOLS 10 Handy laser welding machine 12 Handy welding torch 14 Welding torch main body 16 Nozzle 16f Nozzle tip surface 18 Acceleration sensor 20 Guide plate 20f Guide plate support surface 22 Device housing 24 Fiber laser oscillator (laser oscillator)
Reference Signs List 26 optical fiber 28 control device 30 laser control unit 32 moving speed acquisition unit 34 processing condition update unit S spot of pulsed laser beam H worker's hand W1 work (metal plate)
W2 Work (metal plate)
L Planned joining point B Weld (weld bead)

Claims (4)

A handy welding torch for irradiating a pulsed laser beam toward a joint between two workpieces;
A laser oscillator that is optically connected to the handy welding torch and outputs pulsed laser light;
A laser control unit that controls the laser oscillator based on a processing program,
A moving speed obtaining unit for obtaining a moving speed of the handy welding torch,
Based on the acquired moving speed of the handy welding torch, the repetition frequency of the pulse laser light among the processing conditions set in the processing program is set so that the overlap rate of the spot of the pulse laser light becomes a predetermined overlap rate. A handy laser welding machine, comprising: a processing condition updating unit for updating. An acceleration sensor for detecting an acceleration of the handy welding torch,
The handy laser welding machine according to claim 1, wherein the moving speed obtaining unit obtains the moving speed of the handy welding torch by estimation based on a detection result from the acceleration sensor. While moving the handy welding torch, by controlling the laser oscillator based on the processing program, and by irradiating the pulse laser light from the handy welding torch, when laser welding two workpieces along the planned joint,
Obtain the moving speed of the handy welding torch,
Based on the acquired moving speed of the handy welding torch, the repetition frequency of the pulse laser light among the processing conditions set in the processing program is set so that the overlap rate of the spot of the pulse laser light becomes a predetermined overlap rate. A laser welding method characterized by updating. Detecting the acceleration of the handy welding torch,
4. The laser welding method according to claim 3, wherein a moving speed of the handy welding torch is obtained by estimation based on the detected acceleration of the handy welding torch. 5.

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