Handy laser welding machine and control method for handy laser welding machine

Abstract

A filler wire feeding machine (15) uses a motor (152) to feed out a filler wire (16). A motor driver (13) rotates the motor (152) in order to feed out the filler wire 16, and drives the motor (152) so as to stop the rotating motor (152). The motor driver (13) sets the absolute value of the positive rotational acceleration when the motor (152), the rotation of which has stopped, starts to rotate so as to be lower than the absolute value of the negative rotational acceleration when the rotating motor (152) stops rotating.

Description

[Technical Field]

[0001] The present invention relates to a handy laser welder and a method for controlling a handy laser welder. [Background technology]

[0002] Patent Document 1 describes a robot-type laser welder. When the laser welder described in Patent Document 1 outputs an operation command to end laser welding, it stops emitting a laser beam and supplying a filler wire, and after a predetermined time has elapsed, it rewinds the filler wire and applies tension to the filler wire. Next, the laser welder described in Patent Document 1 emits a laser beam after a predetermined time has elapsed, and cuts the tensioned filler wire. The control operation for cutting the filler wire described in Patent Document 1 can prevent a lump of molten metal from forming at the tip of the cut filler wire. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-120179 Summary of the Invention

[0004] One example of a laser welding machine is a handheld laser welding machine in which an operator welds a workpiece while holding a welding torch. Handheld laser welding machines typically do not have a filler wire rewinding function, and therefore cannot execute the control operation for cutting the filler wire as described in Patent Document 1. Furthermore, because the operations performed when welding workpieces differ between robot-type laser welding machines and handheld laser welding machines, it is not appropriate to employ the control operation for cutting the filler wire as described in Patent Document 1. It is necessary to cut the filler wire using a control operation suitable for handheld laser welding machines.

[0005] A first aspect of one or more embodiments is a welding torch that is held by an operator and includes: a laser oscillator that emits a laser beam; a filler wire feeder that feeds a filler wire using a motor; a motor driver that rotates the motor to feed the filler wire and drives the motor to stop the rotating motor; an injection switch that instructs irradiation of a laser beam; and a guide mechanism that guides the filler wire fed from the filler wire feeder to a welding point. The welding torch includes: a welding torch that is held by an operator; and a welding torch that controls the laser oscillator to emit a laser beam when irradiation of a laser beam is instructed by the injection switch; a control device that instructs the motor driver to rotate the motor so that the filler wire is fed out by the filler wire feeder, controls the laser oscillator not to emit a laser beam when the emission switch does not instruct laser beam irradiation, and instructs the motor driver to stop the rotation of the motor so that the filler wire feeder does not feed out the filler wire, wherein 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 is rotating, stops rotating.

[0006] According to a first aspect of one or more embodiments, the absolute value of the positive rotational acceleration when the motor, which has stopped rotating, starts to rotate is set to be smaller than the absolute value of the negative rotational acceleration when the motor, which is rotating, stops rotating, thereby preventing a lump of molten metal from forming at the tip of the cut filler wire.

[0007] In a second aspect of one or more embodiments, an operator holds a welding torch and operates an injection switch included in the welding torch, whereby the welding torch instructs a control device to irradiate a laser beam from the welding torch and to feed out a filler wire from a filler wire feeder, the control device controls a laser oscillator to supply a laser beam to the welding torch and controls a motor driver that drives a motor included in the filler wire feeder to rotate the motor and feed out the filler wire, and when the operator completes welding of a welding point and releases the operation of the injection switch, the welding torch instructs the control device to stop irradiating the laser beam from the welding torch and to stop feeding out the filler wire from the filler wire feeder, and the control device controls the laser oscillator to stop supplying the laser beam to the welding torch and controls a motor driver that drives the motor included in the filler wire feeder to rotate the motor and feed out the filler wire. and controls the motor driver to stop feeding out the filler wire, stopping the welding torch from emitting a laser beam and stopping the feeding of the filler wire, and in a state where the operator operates the injection switch for a predetermined short time to cut the filler wire, the welding torch instructs the control device to emit a laser beam from the welding torch and to feed out the filler wire from 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 to feed out the filler wire, and the motor driver sets the absolute value of the positive rotational acceleration when the motor, which has stopped rotating, starts to rotate smaller than the absolute value of the negative rotational acceleration when the motor, which is rotating, stops rotating.

[0008] According to a second aspect of one or more embodiments, the absolute value of the positive rotational acceleration when the motor, which has stopped rotating, starts to rotate is set to be smaller than the absolute value of the negative rotational acceleration when the motor, which is rotating, stops rotating, thereby preventing a lump of molten metal from forming at the tip of the cut filler wire. [Effects of the Invention]

[0009] According to one or more embodiments of the handy laser welder and the control method for the handy laser welder, the filler wire can be cut with a control operation suitable for the handy laser welder. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a handheld laser welder according to one or more embodiments. [Figure 2] FIG. 2 is a time series chart illustrating a first example of the relationship between the one-shot power of a laser beam for cutting a filler wire and the rotational speed of a motor in a handheld laser welder according to one or more embodiments. [Figure 3] FIG. 3 is a time series chart illustrating a second example of the relationship between the one-shot power of the laser beam for cutting the filler wire and the rotational speed of the motor in a handheld laser welder according to one or more embodiments. [Figure 4] FIG. 4 is a time series chart illustrating a third example of the relationship between the one-shot power of the laser beam for cutting the filler wire and the rotational speed of the motor in a handheld laser welder according to one or more embodiments. [Figure 5] FIG. 5 is a time series chart illustrating a fourth example of the relationship between the one-shot power of the laser beam for cutting the filler wire and the rotational speed of the motor in a handheld laser welder according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0011] A handheld 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 feeds the filler wire using a motor. The motor driver drives the motor to rotate to feed the filler wire and to stop the rotating motor. The welding torch has an emission switch that instructs irradiation of the laser beam and a guide mechanism that guides the filler wire fed from the filler wire feeder to the welding point, and is held by an operator.

[0012] When the emission switch commands the control device to emit a laser beam, the control device controls the laser oscillator to emit a laser beam and commands the motor driver to rotate the motor to feed the filler wire using the filler wire feeder.When the emission switch does not command the control device to emit a laser beam, the control device controls the laser oscillator not to emit a laser beam and commands the motor driver to stop rotating the motor to prevent the filler wire feeder from feeding the filler wire.

[0013] The motor driver sets the absolute value of the positive rotation acceleration when the motor that has stopped rotating starts to rotate smaller than the absolute value of the negative rotation acceleration when the rotating motor stops rotating.

[0014] A method for controlling a handheld laser welder according to one or more embodiments controls a handheld laser welder as follows: An operator holds a welding torch and operates an injection switch on the welding torch to instruct a control device to cause the welding torch to emit a laser beam and a filler wire feeder to feed a filler wire. The control device controls a laser oscillator to supply a laser beam to the welding torch, and controls a motor driver that drives a motor on the filler wire feeder to rotate the motor and feed the filler wire.

[0015] When the operator completes welding the welding spot and releases the operation of the injection switch, the control device is instructed to stop the welding torch from emitting the laser beam and to stop the filler wire feeder from feeding out the filler wire. 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 and stop feeding out the filler wire.

[0016] With the welding torch halting irradiation of the laser beam and the filler wire feeding stopped, the operator operates the injection switch for a predetermined short time to cut the filler wire, thereby instructing the control device to irradiate the welding torch with the laser beam and feed out the filler wire using 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 out the filler wire.

[0017] The motor driver sets the absolute value of the positive rotation acceleration when the motor that has stopped rotating starts to rotate smaller than the absolute value of the negative rotation acceleration when the rotating motor stops rotating.

[0018]

[0016] Hereinafter, a handy laser welder and a control method for a handy laser welder according to one or more embodiments will be described in detail with reference to the accompanying drawings. Fig. 1 shows a handy laser welder 100 according to one or more embodiments.

[0019] As shown in Fig. 1, handheld laser welding machine 100 includes control device 10, laser oscillator 11, motor driver 13, filler wire feeder 15, and welding torch 17. Control device 10 and motor driver 13 are connected by signal cable 12. Motor driver 13 and filler wire feeder 15 are connected by signal cable 14. Welding torch 17 is connected to laser oscillator 11 by optical fiber 18 and to control device 10 by signal cable 19.

[0020] The control device 10 can be configured with one or more computers. The control device 10 may be configured with an NC (Numerical Control) device. The control device 10 has a memory for storing processing programs and the like, and a central processing unit (CPU) for interpreting and executing the processing programs. The control device 10 controls the laser oscillator 11 based on the welding conditions set in the processing program.

[0021] The laser oscillator 11 is any laser oscillator such as a fiber laser oscillator, a YAG laser oscillator, a CO2 laser oscillator, or a semiconductor laser oscillator. The motor driver 13 has an operation unit 131 and a contact switch 132. A contactless switch may be used instead of the contact switch 132. The filler wire feeder 15 has a reel 151 that winds the filler wire 16 and a motor 152 that feeds the filler wire 16.

[0022] Welding torch 17 has nozzle 171, which is provided at the tip of welding torch 17, for emitting a laser beam, and emission switch 172, which an operator holding welding torch 17 presses with his or her finger to instruct irradiation of the laser beam. The action of pressing emission switch 172 is an example of an operation to instruct irradiation of the laser beam. The action of releasing pressed emission switch 172 is an example of an operation to cancel the instruction to emit the laser beam. When emission switch 172 is not pressed, no instruction to emit the laser beam has been given and irradiation of the laser beam is stopped.

[0023] When emission switch 172 is pressed, a laser beam emitted by laser oscillator 11 is supplied to welding torch 17 via optical fiber 18. Welding torch 17 incorporates an optical system (not shown) for focusing the laser beam and emitting it from nozzle 171. Welding torch 17 may incorporate an acceleration sensor 175 for detecting the direction of movement of nozzle 171 and its acceleration.

[0024] A guide pipe 174 is attached to the base of the nozzle 171 via a bracket 173. The filler wire 16 supplied from the filler wire supply device 15 is inserted into the guide pipe 174. The filler wire 16 is guided by the guide pipe 174 and led to the tip of the nozzle 171. The guide pipe 174 is a guide mechanism for guiding the filler wire 16 fed from the filler wire supply device 15 to the welding location.

[0025] When an operator holds welding torch 17 in handy laser welder 100 configured as described above and presses emission switch 172, welding torch 17 transmits an emission command signal to control device 10 via signal cable 19 to instruct it to emit a laser beam. Control device 10, upon receiving the emission command signal, instructs laser oscillator 11 to emit a laser beam. Laser oscillator 11 supplies a laser beam to welding torch 17 via optical fiber 18.

[0026] Furthermore, upon receiving the injection instruction signal, control device 10 transmits a supply instruction signal to motor driver 13 to supply filler wire 16 to welding torch 17. Upon receiving the supply instruction signal, motor driver 13 turns on contact switch 132 to drive motor 152 in filler wire feeder 15 to rotate motor 152. Using operation unit 131, the operator can set the maximum rotational speed at which motor 152 feeds out filler wire 16, the positive rotational acceleration from when motor 152 starts to rotate until it reaches the maximum rotational speed, and the negative rotational acceleration when motor 152 stops rotating.

[0027] In this way, when an operator presses the injection switch 172 of the welding torch 17 to weld a line-shaped weld L, for example, by welding the end faces of two sheet metal workpieces W1 and W2 facing each other, a laser beam is emitted from the nozzle 171 and the filler wire 16 is fed out. The filler wire feeder 15 has guide rollers (not shown), which feed the filler wire 16 out of the filler wire feeder 15. The guide rollers are composed of a drive roller that is driven to rotate by a motor 152 and a driven roller that is driven by the rotation of the drive roller. The drive roller and the driven roller sandwich the filler wire 16. Any curl of the filler wire 16 wound around the reel 151 is straightened as it passes through the guide rollers.

[0028] The worker brings the tip of nozzle 171 into contact with welding spot L and moves welding torch 17 along welding spot L to weld workpieces W1 and W2. If welding torch 17 has an acceleration sensor 175 built in, control device 10 can estimate the movement speed of welding torch 17 based on the movement direction and acceleration detected by acceleration sensor 175. Based on the estimated movement speed of welding torch 17, control device 10 can control the overlap rate of the laser beam spots so that weld bead WB is properly formed.

[0029] Incidentally, motor 152 does not need to be a high-performance, expensive motor such as a servo motor or stepping motor capable of feedback control. Motor 152 may be an inexpensive motor that does not allow feedback control. Motor 152 may also be an induction motor. Here, motor 152 is assumed to be an AC motor that is an asynchronous induction motor. Motor 152 may be a brushless motor or a brushed motor.

[0030] By using an inexpensive motor that does not allow feedback control as motor 152, filler wire feeder 15 can be made inexpensive, and as a result handheld laser welder 100 can be made inexpensive.

[0031] For example, when a worker completes welding while pulling welding torch 17 toward himself along welding location L, he releases the depressed injection switch 172. This causes welding torch 17 to stop sending the injection command signal, and control device 10 instructs laser oscillator 11 to stop emitting the laser beam. Control device 10 also stops sending the supply command signal to motor driver 13, and motor driver 13 drives motor 152 in filler wire feeder 15 to stop its rotation. This causes welding torch 17 to stop emitting the laser beam from nozzle 171, and filler wire feeder 15 to stop feeding filler wire 16.

[0032] In this state, filler wire 16 is connected to weld bead WB, and it is necessary to cut filler wire 16. Therefore, the worker pulls welding torch 17, for example, diagonally upward toward the front, and simultaneously presses and releases injection switch 172 for a predetermined short time, causing a laser beam to be emitted from nozzle 171 for an extremely short time. The predetermined short time during which the worker presses and releases injection switch 172 is, for example, about 200 ms to 500 ms.

[0033] The extremely short time laser beam emission for cutting filler wire 16 is referred to as one-shot output. Filler wire 16 is cut by the one-shot output of the laser beam, and the operator can move welding torch 17 away from welding point L by pulling welding torch 17 diagonally upward toward the operator.

[0034] 2 to 5, examples of the relationship between the one-shot output of the laser beam for cutting the filler wire 16 and the rotational speed of the motor 152 in the handheld laser welding machine 100 will be described. In Fig. 2 to Fig. 5, in a time series chart with the horizontal axis representing time and the vertical axis representing the laser output, LO represents the one-shot output, and in a time series chart with the horizontal axis representing time and the vertical axis representing the motor rotational speed, ACp represents the positive rotational acceleration when the motor 152 starts to rotate, and ACn represents the negative rotational acceleration when the motor 152 stops rotating.

[0035] 2 and 3 show an example of the relationship between the one-shot output LO and the rotational speed of the motor 152 when the motor driver 13 has a contactless switch instead of the contact switch 132. The duration of the one-shot output LO shown in FIG. 2 is, for example, approximately 500 ms. As shown in FIG. 2, when the operator presses the injection switch 172 at time t0, the motor 152 starts rotating at approximately time t0 because the motor driver 13 has a contactless switch. The rotational speed of the motor 152 increases to a maximum rotational speed RSmax at a positive rotational acceleration ACp. After rotating at the maximum rotational speed RSmax for a short period of time, the rotational speed decreases at a negative rotational acceleration ACn and the motor 152 stops rotating.

[0036] Figure 3 shows an example of the relationship between the one-shot output LO and the rotational speed of motor 152 when the one-shot output LO is set to a shorter time than in Figure 2. The time of the one-shot output LO shown in Figure 3 is approximately 200 ms. If the time of the one-shot output LO is short, even if the rotational speed of motor 152 increases at positive rotational acceleration ACp, the rotational speed will decrease at negative rotational acceleration ACn and stop before reaching maximum rotational speed RSmax.

[0037] 2 and 3, 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 the motor 152 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 that is fed out is small, and it is possible to prevent a lump of molten metal from being generated at the tip of the cut filler wire 16.

[0038] As shown in FIGS. 2 and 3, the motor driver 13 rotates the motor 152 only in the direction in which the filler wire 16 is fed out, and does not rotate the motor 152 in the direction in which the filler wire 16 is unwound.

[0039] 4 and 5 show an example of the relationship between the one-shot output LO and the rotational speed of the motor 152 when the motor driver 13 has the contact switch 132. As shown in Fig. 4, when an operator presses the ejection switch 172 at time t0, the motor 152 does not start rotating at time t0, but starts rotating at time t1, after the delay time DT has elapsed, because the motor driver 13 has the contact switch 132. In other words, the motor 152 starts rotating at a timing delayed by the delay time DT from the timing when the operator presses the ejection switch 172. The contact switch 132 functions as a delay device that generates the delay time DT.

[0040] 2, the rotation speed of motor 152 increases to a maximum rotation speed RSmax at a positive rotation acceleration ACp. After rotating at the maximum rotation speed RSmax for a short period of time, motor 152 decreases its rotation speed at a negative rotation acceleration ACn and stops rotating.

[0041] Figure 5 shows an example of the relationship between the one-shot output LO and the rotational speed of the motor 152 when the one-shot output LO is set to a shorter time than in Figure 4. As in Figure 4, when the operator presses the injection switch 172 at time t0, the motor 152 starts rotating at time t1, after the delay time DT has elapsed. As in Figure 3, because the one-shot output LO time is short, even if the rotational speed of the motor 152 increases at the positive rotational acceleration ACp, the rotational speed decreases at the negative rotational acceleration ACn and stops before reaching the maximum rotational speed RSmax.

[0042] In FIGS. 4 and 5, the delay time DT caused by the operation of the contact switch 132 is about 100 ms.

[0043] As shown in FIGS. 4 and 5, the motor driver 13 rotates the motor 152 only in the direction in which the filler wire 16 is fed out, and does not rotate the motor 152 in the direction in which the filler wire 16 is unwound.

[0044] If the motor driver 13 is configured to have a contact switch 132, the motor 152 starts rotating at time t1, which is when the delay time DT has elapsed since the operator pressed the injection switch 172 at time t0. Therefore, the amount of filler wire 16 fed out is even smaller than in the cases of Figures 2 and 3, which makes it possible to further prevent a lump of molten metal from forming at the tip of the cut filler wire 16 compared to the cases of Figures 2 and 3. Therefore, Figures 4 and 5 are preferable to Figures 2 and 3, and it is preferable that the motor driver 13 drives the motor 152 so as to turn the rotation of the motor 152 on and off using the contact switch 132.

[0045] As described above, the control method for a handheld laser welder according to one or more embodiments controls handheld laser welder 100 as follows: When an operator holds welding torch 17 and operates injection switch 172 of welding torch 17, welding torch 17 instructs control device 10 to irradiate a laser beam from welding torch 17 and to feed filler wire 16 from filler wire feeder 15. Control device 10 controls laser oscillator 11 to supply a laser beam to welding torch 17, and controls motor driver 13 that drives motor 152 of filler wire feeder 15 to rotate motor 152 and feed filler wire 16.

[0046] When the worker completes welding the welding spot and releases the operation of injection switch 172, welding torch 17 instructs control device 10 to stop the irradiation of the laser beam by welding torch 17 and to stop the feeding of filler wire 16 by filler wire feeder 15. Control device 10 controls laser oscillator 11 to stop the supply of the laser beam to welding torch 17, and controls motor driver 13 to stop the rotation of motor 152 and stop the feeding of filler wire 16.

[0047] With welding torch 17 halting irradiation of the laser beam and halting feeding of filler wire 16, the operator operates injection switch 172 for a predetermined short period of time to cut filler wire 16. This causes welding torch 17 to instruct control device 10 to radiate the laser beam from welding torch 17 and to feed filler wire 16 from filler wire feeder 15.

[0048] Control device 10 controls laser oscillator 11 to supply a laser beam to welding torch 17, and controls motor driver 13 to rotate motor 152 to feed filler wire 16. Motor driver 13 sets the absolute value of positive rotational acceleration ACp when motor 152, which has stopped rotating, starts to rotate to be smaller than the absolute value of negative rotational acceleration ACn when motor 152, which is rotating, stops rotating.

[0049] The present invention is not limited to one or more of the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0050] This application claims priority based on 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 laser oscillator that emits a laser beam; a filler wire feeder that feeds the filler wire using a motor; a motor driver that drives the motor to rotate the motor to feed out the filler wire and to stop the rotating motor; a welding torch held by an operator, the welding torch having an injection switch that instructs irradiation of a laser beam and a guide mechanism that guides the filler wire fed from the filler wire feeder to a welding point; a control device that, when the emission switch instructs irradiation of a laser beam, controls the laser oscillator to emit a laser beam and instructs the motor driver to rotate the motor so that the filler wire feeder feeds the filler wire, and, when the emission switch does not instruct irradiation of a laser beam, controls the laser oscillator not to emit a laser beam and instructs the motor driver to stop rotating the motor so that the filler wire feeder does not feed the filler wire; Equipped with The motor driver sets the absolute value of the positive rotation acceleration when the motor, which has stopped rotating, starts to rotate to be smaller than the absolute value of the negative rotation acceleration when the motor, which is rotating, stops rotating. Handy laser welding machine.

2. 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.

2. The handy laser welder according to claim 1.

3. an operator holds a welding torch and operates an injection switch of the welding torch, whereby the welding torch instructs a control device to irradiate a laser beam by the welding torch and to feed a filler wire by a filler wire feeder; the control device controls a laser oscillator to supply a laser beam to the welding torch, and controls a motor driver that drives a motor included in the filler wire supply device to rotate the motor and feed out the filler wire; When the operator completes welding of the welding portion and releases the operation of the injection switch, the welding torch instructs the control device to stop emitting the laser beam by the welding torch and to stop feeding the filler wire by the filler wire feeder; the control device controls the laser oscillator to stop supplying the laser beam to the welding torch, and controls the motor driver to stop rotation of the motor and stop feeding of the filler wire; When the worker stops emitting the laser beam from the welding torch and stopping the feeding of the filler wire, he or she operates the injection switch for a predetermined short period of time to cut the filler wire, whereby the welding torch instructs the control device to irradiate the laser beam from the welding torch and to feed out the filler wire by 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 to feed out the filler wire; The motor driver sets the absolute value of the positive rotation acceleration when the motor, which has stopped rotating, starts to rotate to be smaller than the absolute value of the negative rotation acceleration when the motor, which is rotating, stops rotating. A method for controlling a handheld laser welding machine.

4. 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.

4. The method for controlling a handy laser welder according to claim 3.

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