JP2006263761A - Apparatus for judging applicability of laser welding, and apparatus of laser welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for judging applicability of laser welding, which apparatus can prevent the generation of poor laser welding due to the bad condition of the laser welding apparatus. <P>SOLUTION: The apparatus 10 for judging applicability of laser welding is composed of a metallic plate 12 irradiated by the laser beam R radiated from a laser oscillator 3 of a laser welding apparatus 1, a temperature sensor 14 for detecting the temperature change and temperature distribution on the metallic plate 12 irradiated by the laser beam R, and a judging section 16 for judging applicability of laser welding by calculating the energy of the laser beam R based on the temperature change of the metallic plate 12 detected by the temperature sensor 14, and based on the calculated energy of the laser beam R and the temperature distribution on the metallic plate 12 detected by the temperature sensor 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser welding availability determination device that prevents a welding failure from occurring due to a failure of a laser welding device, and a laser welding device including a laser welding availability determination device.

Conventionally, resistance welding apparatuses that use electrical resistance have been often used in welding operations, but laser welding apparatuses that use high energy density laser light are also used.
The determination of the welding state of laser welding is often made visually by an inspector offline after welding. In the visual inspection by the inspector, the burden on the inspector is large, and there is a possibility that the determination result varies depending on the skill level of the inspector. Therefore, the determination of the welding state is often performed using a determination device.

As such a determination device, the following device has been proposed (see Patent Document 1). In this determination apparatus, the intensity of plasma light and reflected light emitted from a steel plate to be welded during laser welding is detected as the detection light intensity, and a predetermined period is selected from one period of detection light intensity corresponding to one pulse of laser light. An interval is set in advance as an extraction interval, and a feature value for each pulse is extracted for each pulse of the laser beam based on the detected light intensity in the extraction interval, and a determination value of the welding state for each steel plate is used for each pulse in the steel plate. The extreme value of the characteristic value is obtained, and the welding state for each steel plate is determined by comparing the extreme value with a predetermined threshold value.
JP 2000-153379 A

  However, the conventional determination of the welding state of laser welding is a determination after welding. Even if a welding failure is found in this determination, it is determined whether the cause of the welding failure exists in the laser welding apparatus or in the arrangement of the workpieces, typically in the misalignment between the butt portions of the steel plates. Cannot be identified immediately. For this reason, the work line must be stopped for a long time until the cause of the welding failure is specified, and work efficiency is reduced. This also reduces the production efficiency because the weld defects must be re-welded.

In addition, as a malfunction of the laser welding apparatus that causes welding failure, for example, contamination of the reflecting mirror that guides the laser light, displacement of the position, and the like can be considered.
The present invention solves the above-described problems, and an object of the present invention is to provide a laser welding availability determination device capable of preventing the occurrence of poor welding due to a failure of a laser welding device, and a laser including a laser welding availability determination device. It is to provide a welding device.

  The present invention adopts the following configuration in order to solve the problem. The apparatus for determining whether laser welding is possible according to the invention of claim 1 includes a metal plate irradiated with a laser beam oscillated from a laser oscillator of the laser welding apparatus, and a temperature change and a temperature distribution of the metal plate irradiated with the laser beam. A temperature detector to detect, and calculate the energy of the laser beam from the temperature change of the metal plate detected by the temperature detector, the calculated laser beam energy and the temperature distribution of the metal plate detected by the temperature detector And a determination unit that determines whether laser welding is possible or not.

  Before performing laser welding, a laser beam is emitted from a laser oscillator to a metal plate, and a temperature detector detects a temperature change and a temperature distribution of the metal plate irradiated with the laser beam. A determination part calculates the energy of the laser beam irradiated to the metal plate from the temperature change of the metal plate detected by the temperature detector. Then, the determination unit determines whether the laser oscillator can oscillate laser light having sufficient energy for laser welding from the calculated energy of laser light, and from the temperature distribution of the metal plate, Therefore, it is determined whether or not the laser oscillator can oscillate laser light having an appropriate temperature distribution.

According to a second aspect of the present invention, there is provided a laser welding apparatus comprising: the laser welding availability determination apparatus according to the first aspect; and a laser beam transmission means for guiding a laser beam oscillated from a laser oscillator to a workpiece.
Since the laser welding availability determination device determines whether the laser light emitted from the laser oscillator of the laser welding device has sufficient energy and appropriate temperature distribution for laser welding, laser welding is performed before laser welding. It is possible to find defects in the apparatus and prevent in advance occurrence of welding defects due to defects in the laser welding apparatus.
The laser light transmission means is conventionally used as means for changing the optical path of laser light, and examples thereof include a reflecting mirror and a prism.

  Since the present invention is the laser welding determination device and the laser welding device as described above, it is possible to prevent the occurrence of poor welding due to the failure of the laser welding device.

The best mode for carrying out the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a laser welding apparatus according to the present invention, FIG. 2 is an explanatory diagram of a state of a metal plate irradiated with laser light having a temperature distribution suitable for laser welding, and FIG. 3 shows a temperature distribution inappropriate for laser welding. It is state explanatory drawing of the metal plate which irradiated the laser beam which has.
A laser welding apparatus 1 shown in FIG. 1 includes a laser oscillator 3, reflecting mirrors 5 </ b> A and 5 </ b> B, a condenser lens 7, and a laser welding availability determination apparatus 10. The laser oscillator 3 has the same configuration as a conventional laser oscillator and is configured to be able to oscillate laser light R for laser welding. The reflecting mirror 5A and the condensing lens 7 are disposed so as to be able to irradiate the butted portion 22 between the steel plate 20A and the steel plate 20B, which are workpieces, with the laser beam R oscillated from the laser oscillator 3. Further, the reflecting mirror 5B is movable. By placing the reflecting mirror 5B on the optical path of the laser beam R between the reflecting mirror 5A and the condensing lens 7, it is possible to guide the laser beam R to the laser weldability determination device 10, and the reflecting mirror 5B is turned into a laser. By retracting from the optical path of the light R, the laser light R can be guided to the abutting portion 22.

  The laser weldability determination device 10 includes a metal plate 12, a temperature detector 14, and a determination unit 16. The metal plate 12 is a copper plate plated with gold, the surface of the metal plate 12 faces the reflecting mirror 5B, and the metal plate 12 can be irradiated with the laser light R guided from the reflecting mirror 5B to the surface of the metal plate 12. ing. The temperature detector 14 is an infrared radiation thermometer, and is installed on the opposite side of the reflecting mirror 5B with the metal plate 12 interposed therebetween, and is configured to be able to measure temperature change data D1 and temperature distribution data D2 of the metal plate 12. Yes. The temperature detector 14 is connected to the determination unit 16, and the determination unit 16 is configured to be able to receive the temperature change data D1 and the temperature distribution data D2 from the temperature detector 14.

The determination unit 16 has programs P1, P2, and P3.
The program P1 is a program for calculating the energy of the laser light R based on the temperature change data D1. The calculation contents of the program P1 will be specifically described. First, the program P1 calculates the temperature change rate of the metal plate 12 from the temperature change data D1, calculates the energy incident on the metal plate 12 from the laser beam R from this temperature change rate, and calculates the energy of the laser beam R. To do. Next, it is determined from the calculated energy of the laser beam R whether or not the laser oscillator 3 can oscillate a laser beam having sufficient energy for laser welding.

  The program P2 is a program for detecting the temperature distribution of the laser light R based on the temperature distribution data D2. The calculation contents of the program P2 will be specifically described (see FIGS. 2 and 3). The program P1 first detects a circular irradiation range 18 where the laser beam R is irradiated on the metal plate 12 from the temperature distribution data D2, and determines the center O1 of the irradiation range 18 and the irradiation position O2 of the optical axis of the laser beam R. To detect. Next, the distance d between the center O1 and the irradiation position O2 is calculated. If the distance d is smaller than a predetermined amount, the laser oscillator 3 can oscillate laser light having an appropriate temperature distribution for laser welding. If the distance d is larger than a predetermined amount, it is determined that the laser oscillator 3 cannot oscillate laser light having an appropriate temperature distribution for laser welding.

FIG. 2 shows a case where the center O1 and the irradiation position O2 coincide. In this case, if the laser beam R is applied to the butt portion 22 between the steel plate 20A and the steel plate 20B, the temperature reaches a peak at the center O1 of the irradiation range 18, and welding failure of the butt portion 22 does not occur.
FIG. 3 shows a case where the center O1 and the irradiation position O2 are shifted without matching. In this case, even when the butt portion 22 between the steel plate 20A and the steel plate 20B is irradiated with the laser light R, the temperature does not reach a peak at the center O1 of the irradiation range 18, and welding failure occurs in the butt portion 22.

  The program P3 is a program that issues an alarm based on the calculation results of the programs P1 and P2. The calculation contents of the program P3 will be specifically described. When the program P1 determines that the laser oscillator 3 cannot oscillate laser light having sufficient energy for laser welding, the program P3 issues an alarm. Further, when the program P2 determines that the laser oscillator 3 cannot oscillate laser light having an appropriate temperature distribution for laser welding, the program P3 issues an alarm. Then, the program P1 determines that the laser oscillator 3 can oscillate laser light having sufficient energy for laser welding, and the program if the laser oscillator 3 can oscillate laser light having an appropriate temperature distribution for laser welding. When P2 determines, program P3 does not issue an alarm.

This embodiment is configured as described above, and the operation thereof will be described next.
First, the output of the laser beam R oscillated from the laser oscillator 3 of the laser welding apparatus 1 is lowered to, for example, 50% of the output of the laser beam R at the time of laser welding, and the reflecting mirror 5B is made into the reflecting mirror 5A and the condenser lens 7. The laser beam R is guided to the laser weldability determination device 10 and the metal plate 12 is irradiated with the laser beam R.

The metal plate 12 irradiated with the laser beam R is heated by the energy of the laser beam R. The temperature detector 14 measures the temperature change data D1 and the temperature distribution data D2 of the metal plate 12 and transmits them to the determination unit 16.
In the determination unit 16, the program P1 calculates the energy of the laser beam R based on the temperature change data D1, and the laser oscillator 3 oscillates the laser beam having sufficient energy for laser welding based on the calculation result. Judge whether to get.

Next, the program P2 detects the temperature distribution of the laser light R based on the temperature distribution data D2, and determines whether the laser oscillator 3 can oscillate laser light having an appropriate temperature distribution for laser welding.
Then, the program P3 issues an alarm according to the calculation results of the programs P1 and P2. The program P3 issues an alarm when the laser oscillator 3 cannot oscillate laser light having sufficient energy for laser welding or when laser light having an appropriate temperature distribution for laser welding is emitted from the laser oscillator 3. Is a case where oscillation cannot occur. When an alarm is issued, the laser welding apparatus 1 is adjusted without performing laser welding by the laser welding apparatus 1. If the alarm is not issued, the reflecting mirror 5B is retracted from between the reflecting mirror 5A and the condenser lens 7 to form a laser beam transmitting means for guiding the laser beam to weld the workpiece, Laser welding with increased output.

Since it is the laser welding possibility determination apparatus 10 as described above, before performing laser welding with the laser welding apparatus 1, it is possible to find a defect in the laser welding apparatus 1 and adjust the laser welding apparatus 1. Therefore, it is prevented that welding failure occurs due to the failure of the laser welding apparatus 1, and even when the welding failure occurs, the cause of the welding failure may be a deviation of the butt portion 22 between the steel plate 20A and the steel plate 20B. Recognize. Therefore, the cause of welding failure can be removed in a short time, and the working efficiency of laser welding is improved.
It should be noted that if the temperature distribution of the metal plate 12 is displayed on the monitor based on the temperature distribution data D2 detected by the temperature detector 14, it is convenient when adjusting the defective part of the laser welding apparatus 1.

It is a block diagram of the laser welding apparatus which concerns on this invention. It is state explanatory drawing of the metal plate which irradiated the laser beam which has a suitable temperature distribution for laser welding. It is state explanatory drawing of the metal plate irradiated with the laser beam which has a temperature distribution unsuitable for laser welding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser welding apparatus 3 Laser oscillator 5A, 5B Reflector 7 Condensing lens 10 Laser welding feasibility determination apparatus 12 Metal plate 14 Temperature detector 16 Judgment part 18 Laser light irradiation range 20A, 20B Steel plate (to-be-welded object)
22 Butting part R Laser light P1, P2, P3 Program D1 Temperature change data D2 Temperature distribution data O1 Center of laser light irradiation range O2 Irradiation position of optical axis of laser light

Claims (2)

A metal plate irradiated with laser light oscillated from a laser oscillator of a laser welding apparatus;
A temperature detector for detecting a temperature change and a temperature distribution of the metal plate irradiated with the laser beam;
The laser beam energy is calculated from the temperature change of the metal plate detected by the temperature detector, and laser welding is performed based on the calculated laser beam energy and the temperature distribution of the metal plate detected by the temperature detector. A determination unit for determining whether or not laser welding is possible. The laser welding availability determination device according to claim 1,
And a laser beam transmitting means for guiding a laser beam oscillated from a laser oscillator to an object to be welded.

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