Portable laser welder and control method for a portable laser welder

Abstract

The filler wire feeder (15) feeds out the filler wire (16) by a motor (152). The motor driver (13) drives the motor (152) to rotate the motor (152) to feed out the filler wire (16) and to stop the rotating motor (152). The motor driver (13) sets the absolute value of the positive rotational acceleration at the time when the motor (152) stopped rotating is smaller than the absolute value of the negative rotational acceleration at the time when the rotating motor (152) stopped rotating.

Description

Technical Field

[0001] This invention relates to a portable laser welding machine and a control method for the portable laser welding machine. Background Technology

[0002] Patent Document 1 describes a robotic laser welding machine. When the laser welding machine in Patent Document 1 outputs a command to end laser welding, it stops the emission of the laser beam and the supply of filler wire. After a predetermined time, it rewinds the filler wire and applies tension to it. Then, after another predetermined time, the laser welding machine in Patent Document 1 emits a laser beam to cut the tensioned filler wire. Based on the control action for cutting the filler wire described in Patent Document 1, it is possible to suppress the formation of molten metal at the tip of the cut filler wire.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-120179 Summary of the Invention

[0006] Portable laser welding machines exist where the operator holds the welding torch while welding the workpiece. These portable machines typically lack the function of rewinding the filler wire, making it impossible to perform the filler wire cutting control action described in Patent Document 1. Furthermore, the welding actions differ between robotic and portable laser welding machines; therefore, using the filler wire cutting control action described in Patent Document 1 is inappropriate. A control action suitable for portable laser welding machines is required to cut the filler wire.

[0007] A first aspect of one or more embodiments provides a portable laser welding machine comprising: a laser oscillator that emits a laser beam; a filler wire feeder that feeds filler wire via a motor; a motor driver that drives the motor to rotate by feeding the filler wire and to stop the rotating motor; a welding torch having an injection switch for indicating laser beam irradiation and a guide mechanism for guiding the filler wire fed from the filler wire feeder to the welding site, which is held by an operator; and a control device that, when the laser beam irradiation is indicated by the injection switch... The laser oscillator is controlled to emit a laser beam, the motor driver is instructed to rotate the motor to feed the filler wire through the filler wire feeder, the laser oscillator is controlled not to emit a laser beam when the laser beam is not irradiated by the emission switch, the motor driver is instructed to stop the rotation of the motor to stop the feeder wire from being fed through the filler wire feeder, and the absolute value of the positive rotational acceleration when the motor starts to rotate after it has stopped is set to be smaller than the absolute value of the negative rotational acceleration when the motor stops rotating.

[0008] According to a first aspect of one or more embodiments, the absolute value of the positive rotational acceleration when the rotating motor starts to rotate after it has stopped is set to be smaller than the absolute value of the negative rotational acceleration when the rotating motor stops rotating, thereby suppressing the formation of molten metal blocks at the tip of the cut filler wire.

[0009] A second embodiment of one or more implementations provides a control method for a portable laser welding machine. An operator holds a welding torch and operates an injection switch on the torch. The torch then instructs a control device to irradiate the torch with a laser beam and to feed filler wire via a filler wire feeder. The control device controls a laser oscillator to supply a laser beam to the torch and controls a motor driver to rotate the filler wire feeder to deliver the filler wire. After the operator completes welding, they release the injection switch. The torch then instructs the control device to stop irradiating the torch with the laser beam and to stop feeding filler wire via the filler wire feeder. The control device then controls the laser oscillator to stop supplying the laser beam to the torch. The laser beam supply to the welding torch is controlled, and the motor driver is controlled to stop the rotation of the motor and thus stop the feeding of the filler wire. In the state where the laser beam irradiation through the welding torch has stopped and the feeding of the filler wire has stopped, the operator operates the injection switch for a predetermined short time to cut off the filler wire. Thus, the welding torch instructs the control device to irradiate the laser beam through the welding torch and to feed the filler wire through the filler wire feeder. The control device controls the laser oscillator to supply the laser beam to the welding torch and controls the motor driver to rotate the motor and feed the filler wire. The motor driver sets the absolute value of the positive rotational acceleration when the rotating motor starts to rotate from a stopped state to be smaller than the absolute value of the negative rotational acceleration when the rotating motor stops rotating.

[0010] According to a second embodiment of one or more, the absolute value of the positive rotational acceleration when the rotating motor starts to rotate after it has stopped is set to be smaller than the absolute value of the negative rotational acceleration when the rotating motor stops rotating, thereby suppressing the formation of molten metal blocks at the tip of the cut filler wire.

[0011] Invention Effects

[0012] According to one or more embodiments, a portable laser welding machine and a control method for a portable laser welding machine can cut the filler wire with control actions suitable for the portable laser welding machine. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating a portable laser welding machine with one or more embodiments.

[0014] Figure 2This is a timing diagram illustrating a first example of the relationship between the single output of a laser beam used to cut filler wire and the rotational speed of a motor in a portable laser welding machine according to one or more embodiments.

[0015] Figure 3 This is a timing diagram illustrating a second example of the relationship between the single output of a laser beam used to cut filler wire and the rotational speed of a motor in a portable laser welding machine according to one or more embodiments.

[0016] Figure 4 This is a timing diagram of a third example illustrating the relationship between the single output of a laser beam used to cut filler wire and the rotational speed of a motor in a portable laser welding machine of one or more embodiments.

[0017] Figure 5 This is a timing diagram of a fourth example illustrating the relationship between the single output of a laser beam used to cut filler wire and the rotational speed of a motor in a portable laser welding machine of one or more embodiments. Detailed Implementation

[0018] A portable laser welding machine according to one or more embodiments includes: a laser oscillator, a filler wire feeder, a motor driver, a welding torch, and a control device. The laser oscillator emits a laser beam. The filler wire feeder delivers filler wire via a motor. The motor driver drives the motor to rotate by delivering the filler wire and to stop the rotating motor. The welding torch has an emission switch indicating the irradiation of the laser beam and a guide mechanism for guiding the filler wire delivered from the filler wire feeder to the welding area, and is held by the operator.

[0019] When the laser beam is indicated by the injection switch, the control device controls the laser oscillator to emit the laser beam and instructs the motor driver to rotate the motor so as to feed the filler wire through the filler wire feeder. When the laser beam is not indicated by the injection switch, the control device controls the laser oscillator to stop emitting the laser beam and instructs the motor driver to stop rotating the motor so as not to feed the filler wire through the filler wire feeder.

[0020] The motor driver sets the absolute value of the positive rotational acceleration when the rotating motor starts to rotate from a stopped state to be smaller than the absolute value of the negative rotational acceleration when the rotating motor stops rotating.

[0021] One or more embodiments of the portable laser welding machine are controlled as follows: The operator holds the welding torch and operates the injection switch on the torch, thereby instructing the control device to irradiate the laser beam through the torch and to feed the filler wire through the filler wire feeder. The control device controls the laser oscillator to supply the laser beam to the welding torch and controls the motor driver of the drive motor to rotate the motor on the filler wire feeder to feed the filler wire.

[0022] After the operator completes welding at the designated area, they release the injection switch, thereby instructing the control device to stop the laser beam irradiation through the welding torch and the feeding of filler wire through the filler wire feeder. The control device controls the laser oscillator to stop the supply of the laser beam to the welding torch and controls the motor driver to stop the motor's rotation, thus stopping the feeding of filler wire.

[0023] With the laser beam irradiation through the welding torch stopped and the filler wire feeding stopped, the operator operates the injection switch for a specified short time to cut off the filler wire. This signals the control device to continue laser beam irradiation through the welding torch and to continue filler wire feeding through the filler wire feeder. The control device controls the laser oscillator to supply the laser beam to the welding torch and controls the motor driver to rotate the motor and feed the filler wire.

[0024] The motor driver sets the absolute value of the positive rotational acceleration when the rotating motor starts to rotate from a stopped state to be smaller than the absolute value of the negative rotational acceleration when the rotating motor stops rotating.

[0025] Hereinafter, with reference to the accompanying drawings, a portable laser welding machine and a control method for the portable laser welding machine according to one or more embodiments will be specifically described. Figure 1 Portable laser welding machine 100, representing one or more embodiments.

[0026] like Figure 1 As shown, the portable laser welding machine 100 includes: a control device 10, a laser oscillator 11, a motor driver 13, a filler wire feeder 15, and a welding torch 17. The control device 10 is connected to the motor driver 13 via a signal cable 12. The motor driver 13 is connected to the filler wire feeder 15 via a signal cable 14. The welding torch 17 is connected to the laser oscillator 11 via an optical fiber 18 and to the control device 10 via a signal cable 19.

[0027] The control device 10 can be composed of one or more computers. The control device 10 can also be composed of an NC (Numerical Control) device. The control device 10 has a memory for storing machining programs and a central processing unit (CPU) for interpreting and executing the machining programs. The control device 10 controls the laser oscillator 11 according to the welding conditions set by the machining program.

[0028] The laser oscillator 11 can be any laser oscillator, such as a fiber laser oscillator, YAG laser oscillator, CO2 laser oscillator, or semiconductor laser oscillator. The motor driver 13 has an operating section 131 and a contact switch 132. Alternatively, a non-contact switch can be used instead of the contact switch 132. The filler wire feeder 15 has a spool 151 for winding the filler wire 16 and a motor 152 for feeding the filler wire 16.

[0029] The welding torch 17 has a nozzle 171 for emitting a laser beam located at its front end, and an emission switch 172 that is pressed in by the operator holding the torch 17 with their finger to indicate laser beam irradiation. Pressing in the emission switch 172 is an example of indicating laser beam irradiation. Releasing the pressed emission switch 172 is an example of deactivating the laser beam irradiation indication. The state where the emission switch 172 is not pressed in indicates that laser beam irradiation is not indicated, and laser beam irradiation is stopped.

[0030] With the injection switch 172 pressed in, a laser beam emitted by the laser oscillator 11 is supplied to the welding torch 17 via the optical fiber 18. The welding torch 17 has a built-in optical system (not shown) for focusing the laser beam and ejecting it from the nozzle 171. The welding torch 17 may also have a built-in accelerometer 175 for detecting the direction of movement and acceleration of the nozzle 171.

[0031] At the base of nozzle 171, a conduit 174 is installed via bracket 173. Filler wire 16, supplied from filler wire feeder 15, is inserted through conduit 174. The filler wire 16 is guided by conduit 174 to the tip of nozzle 171. Conduit 174 is a guiding mechanism for guiding the filler wire 16 from filler wire feeder 15 to the welding site.

[0032] When the operator holds the welding torch 17 in the portable laser welding machine 100 configured as described above and presses the injection switch 172, the welding torch 17 sends an injection indication signal to the control device 10 via the signal cable 19, indicating the emission of the laser beam. Upon receiving the injection indication signal, the control device 10 instructs the laser oscillator 11 to emit the laser beam. The laser oscillator 11 supplies the laser beam to the welding torch 17 via the optical fiber 18.

[0033] Additionally, the control device 10, upon receiving the injection instruction signal, sends a supply instruction signal to the motor driver 13, instructing the supply of filler wire 16 to the welding torch 17. Upon receiving the supply instruction signal, the motor driver 13 drives the motor 152 in the filler wire feeder 15 to rotate by activating the contact switch 132. The operator can set the maximum rotational speed at which the motor 152 delivers the filler wire 16, the positive rotational acceleration from the start of rotation until the maximum rotational speed is reached, and the negative rotational acceleration when the motor 152 stops rotating via the operation unit 131.

[0034] Thus, when an operator, for example, wants to weld a linear welding area L where the end faces of two workpieces W1 and W2, which are metal plates, presses the injection switch 172 of the welding torch 17, a laser beam is emitted from the nozzle 171, and filler wire 16 is fed out. The filler wire feeder 15 has a guide roller (not shown) that feeds the filler wire 16 to the outside of the filler wire feeder 15. The guide roller consists of a drive roller driven by the rotation of the motor 152 and a driven roller that follows the rotation of the drive roller. The drive roller and the driven roller hold the filler wire 16. The curl of the filler wire 16 wound on the reel 151 is corrected as it passes through the guide roller.

[0035] The operator brings the tip of nozzle 171 into contact with the welding area L, and moves welding torch 17 along the welding area L to weld workpieces W1 and W2. With an accelerometer 175 built into the welding torch 17, the control device 10 can estimate the moving speed of the welding torch 17 based on the moving direction and acceleration detected by the accelerometer 175. The control device 10 can then control the overlap rate of the laser beam points based on the estimated moving speed of the welding torch 17 to properly form weld seam WB.

[0036] However, motor 152 does not need to be a high-performance and expensive motor like a servo motor or stepper motor capable of feedback control. Motor 152 can be an inexpensive motor that cannot be controlled by feedback. Motor 152 can also be an induction motor. Here, motor 152 is an AC motor and an asynchronous induction motor. Motor 152 can be a brushless motor or a brushed motor.

[0037] By setting motor 152 to an inexpensive motor that cannot be controlled by feedback, the filler wire feeder 15 can be made inexpensive, which in turn makes the portable laser welding machine 100 inexpensive.

[0038] For example, when the operator completes welding by pulling the welding torch 17 forward along the welding area L, the injection switch 172 is released. As a result, the welding torch 17 stops sending the injection indication signal, and therefore, the control device 10 instructs the laser oscillator 11 to stop the emission of the laser beam. Furthermore, the control device 10 stops sending the supply indication signal to the motor driver 13, and therefore, the motor driver 13 drives the motor 152 to stop rotating the motor 152 in the filler wire feeder 15. Thus, the welding torch 17 stops emitting the laser beam from the nozzle 171, and the filler wire feeder 15 stops feeding the filler wire 16.

[0039] In this state, the filler wire 16 is connected to the weld seam WB, and it is necessary to cut the filler wire 16. Therefore, while the operator lifts the welding torch 17 diagonally upwards, for example, to the foreground, the operator presses the injection switch 172 in a specified short time and then moves away, ejecting the laser beam from the nozzle 171 in a very short time. The specified short time for the operator to press the injection switch 172 in and move away is, for example, about 200ms to 500ms.

[0040] The emission of the laser beam for an extremely short time used to cut the filler wire 16 is called a single output. The filler wire 16 is cut by the single output of the laser beam, and the operator lifts the welding torch 17 obliquely upwards and forwards, thereby enabling the welding torch 17 to leave the welding position L.

[0041] use Figures 2-5 Examples of the relationship between the single output of the laser beam used to cut the filler wire 16 in a portable laser welding machine 100 and the rotational speed of the motor 152 will be explained. Figures 2-5 In the timing diagram where the horizontal axis represents time and the vertical axis represents laser output, LO indicates a single output. In the timing diagram where the horizontal axis represents time and the vertical axis represents motor rotation speed, ACp represents the positive rotational acceleration when motor 152 starts rotating, and ACn represents the negative rotational acceleration when motor 152 stops rotating.

[0042] Figure 2 as well as Figure 3 This example illustrates the relationship between a single output LO and the rotational speed of the motor 152 when the motor driver 13 has a non-contact switch instead of a contact switch 132. Figure 2 The single output LO time shown is, for example, approximately 500ms. Figure 2As shown, when the operator presses the injection switch 172 at time t0, the motor 152 begins to rotate approximately at time t0 because the motor driver 13 has a contactless switch. The rotational speed of the motor 152 increases with a positive rotational acceleration ACp to the maximum rotational speed RSmax. After rotating at the maximum rotational speed RSmax for a small period of time, the rotational speed decreases with a negative rotational acceleration ACn and the motor stops rotating.

[0043] Figure 3 Indicates and Figure 2 This is an example of the relationship between the single output LO and the rotational speed of motor 152 when the single output LO is set to a short time. Figure 3 The single output LO time shown is approximately 200ms. When the single output LO time is short, even if the rotational speed of motor 152 increases with a positive rotational acceleration ACp, the rotational speed will decrease with a negative rotational acceleration ACn before reaching the maximum rotational speed RSmax and then stop rotating.

[0044] like Figure 2 as well as Figure 3 As shown, the motor driver 13 sets the absolute value of the positive rotational acceleration when the motor 152, which has stopped rotating, starts to rotate to be smaller than the absolute value of the negative rotational acceleration when it stops rotating. Because the absolute value of the rotational acceleration when the motor 152 starts to rotate is small, the amount of filler wire 16 fed out is very small, which can suppress the formation of molten metal blocks at the tip of the cut filler wire 16.

[0045] like Figure 2 as well as Figure 3 As shown, the motor driver 13 causes the motor 152 to rotate only in the direction of feeding the filler wire 16, and not in the direction of rewinding the filler wire 16.

[0046] Figure 4 and Figure 5 This example illustrates the relationship between a single output LO and the rotational speed of the motor 152 when the motor driver 13 has a contact switch 132. For example... Figure 4 As shown, when the operator presses the injection switch 172 at time t0, because the motor driver 13 has a contact switch 132, the motor 152 does not start rotating at time t0, but starts rotating at time t1 after a delay time DT. That is, the motor 152 starts rotating after a delay time DT from the time the operator presses the injection switch 172. The contact switch 132 functions as a delay device that generates the delay time DT.

[0047] and Figure 2Similarly, the rotational speed of motor 152 increases to its maximum rotational speed RSmax with a positive rotational acceleration ACp. After rotating at the maximum rotational speed RSmax for a small period of time, the rotational speed decreases with a negative rotational acceleration ACn and stops rotating.

[0048] Figure 5 Indicates and Figure 4 Compared to the example of the relationship between the single output LO and the rotational speed of motor 152 when the single output LO is set to a short time, this is different. Figure 4 Similarly, when the operator presses the injection switch 172 at time t0, the motor 152 begins to rotate at time t1 after a delay time DT. Figure 3 Similarly, because the time of a single output LO is short, even if the rotational speed of motor 152 increases with a positive rotational acceleration ACp, the rotational speed will decrease with a negative rotational acceleration ACn before reaching the maximum rotational speed RSmax and then stop rotating.

[0049] exist Figure 4 and Figure 5 In the middle, the delay time DT caused by the action of the contact switch 132 is about 100ms.

[0050] like Figure 4 as well as Figure 5 As shown, the motor driver 13 causes the motor 152 to rotate only in the direction of feeding the filler wire 16, and not in the direction of rewinding the filler wire 16.

[0051] If the motor driver 13 has a structure with a contact switch 132, then regarding the motor 152, the operator presses the injection switch 172 at time t0 and starts rotating at time t1 after a delay time DT. Therefore, the amount of filler wire 16 fed is greater than that of the motor 152. Figure 2 and Figure 3 The situation is even smaller, therefore with Figure 2 and Figure 3 Compared to the previous case, it can further suppress the formation of molten metal blocks at the tip of the cut filler wire 16. Therefore, compared to Figure 2 and Figure 3 compared to, Figure 4 and Figure 5 More preferably, the motor driver 13 drives the motor 152 in a manner that turns the motor 152 on / off by means of a contact switch 132.

[0052] As described above, the control method of one or more embodiments of the portable laser welding machine controls the portable laser welding machine 100 as follows: The operator holds the welding torch 17 and operates the injection switch 172 of the welding torch 17, thereby instructing the control device 10 to irradiate the laser beam through the welding torch 17 and to feed the filler wire 16 through the filler wire feeder 15. The control device 10 controls the laser oscillator 11 to supply the laser beam to the welding torch 17 and controls the motor driver 13 of the drive motor 152 to rotate the motor 152 of the filler wire feeder 15 to feed the filler wire 16.

[0053] After the operator completes the welding of the area, they release the injection switch 172. This causes the welding torch 17 to signal the control device 10 to stop the irradiation of the laser beam through the welding torch 17 and to stop the feeding of the filler wire 16 through the filler wire feeder 15. The control device 10 controls the laser oscillator 11 to stop the supply of the laser beam to the welding torch 17 and controls the motor driver 13 to stop the rotation of the motor 152, thereby stopping the feeding of the filler wire 16.

[0054] With the laser beam irradiation through the welding torch 17 stopped and the feeding of filler wire 16 stopped, the operator operates the injection switch 172 for a specified short time in order to cut off the filler wire 16. As a result, the welding torch 17 instructs the control device 10 to irradiate the laser beam through the welding torch 17 and to feed the filler wire 16 through the filler wire feeder 15.

[0055] The control device 10 controls the laser oscillator 11 to supply a laser beam to the welding torch 17 and controls the motor driver 13 to rotate the motor 152 to feed the filler wire 16. The motor driver 13 sets the absolute value of the positive rotational acceleration ACp when the rotating motor 152 starts to rotate to be smaller than the absolute value of the negative rotational acceleration ACn when the rotating motor 152 stops rotating.

[0056] This invention is not limited to one or more embodiments described above, and various modifications can be made without departing from the spirit of this invention.

[0057] This application claims priority under Japanese Patent Application No. 2021-187768, filed with the Japan Patent Office on November 18, 2021, the entire disclosure of which is incorporated herein by reference.

Claims

1. A portable laser welding machine, characterized in that, have: A laser oscillator that emits a laser beam; A filler wire feeder that delivers filler wire via a motor; A motor driver that drives the motor to feed the filler wire to rotate the motor and to stop the rotating motor; The welding torch, which has an ejection switch for indicating the irradiation of the laser beam and a guide mechanism for guiding the filler wire fed from the filler wire feeder to the welding site, is held by the operator; as well as A control device, when laser beam irradiation is indicated by the injection switch, controls the laser oscillator to emit the laser beam and instructs the motor driver to rotate the motor to feed the filler wire through the filler wire feeder; when laser beam irradiation is not indicated by the injection switch, it controls the laser oscillator to not emit the laser beam and instructs the motor driver to stop rotating the motor to prevent the filler wire from being fed through the filler wire feeder. The motor driver sets the absolute value of the positive rotational acceleration when the motor, which has stopped rotating, starts to rotate to be smaller than the absolute value of the negative rotational acceleration when the motor, which has stopped rotating.

2. The portable laser welding machine according to claim 1, characterized in that, The motor driver has a contact switch. When the motor driver is instructed by the control device to rotate the motor, it turns on the contact switch to rotate the motor.

3. A control method for a portable laser welding machine, characterized in that, The operator holds the welding torch and operates the ejection switch of the torch, thereby instructing the control device to irradiate the torch with a laser beam and to feed the filler wire via a filler wire feeder. The control device controls the laser oscillator to supply a laser beam to the welding torch and controls the motor driver to drive the motor, thereby rotating the motor of the filler wire feeder to deliver the filler wire. The operator completes welding at the designated welding point and releases the injection switch. Consequently, the welding torch signals the control device to stop irradiation by the laser beam passing through the torch and to stop feeding the filler wire via the filler wire feeder. The control device controls the laser oscillator to stop the supply of the laser beam to the welding torch, and controls the motor driver to stop the rotation of the motor, thereby stopping the feeding of the filler wire. With the laser beam irradiation through the welding torch stopped and the feed of the filler wire stopped, the operator operates the injection switch for a predetermined short time to cut off the filler wire. This causes the welding torch to instruct the control device to irradiate the laser beam through the torch and to feed the filler wire through the filler wire feeder. The control device controls the laser oscillator to supply a laser beam to the welding torch and controls the motor driver to rotate the motor and feed the filler wire. The motor driver sets the absolute value of the positive rotational acceleration when the motor, which has stopped rotating, starts to rotate to be smaller than the absolute value of the negative rotational acceleration when the motor, which has stopped rotating.

4. The control method for the portable laser welding machine according to claim 3, characterized in that, The motor driver has a contact switch. When the motor driver is instructed by the control device to rotate the motor, it turns on the contact switch to rotate the motor.

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