JP2006150399A - Laser welding apparatus and laser welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method of laser welding by which laser welding can be carried out for a workpiece with excellent heat balance without delaying welding work. <P>SOLUTION: The laser welding apparatus for carrying out welding by irradiating laser beams on workpieces comprises a laser beam irradiating means for irradiating the laser beam at a required period of a pulse, and an irradiating position changing means for changing the position of the workpiece irradiated with the laser beam for each period of the pulse. The irradiating position changing means changes the position irradiated with the laser beam so that the neighborhood of the position irradiated with the laser beam is not successively irradiated with the laser beam. By this method, the number of irradiation of the laser beams per unit time on the almost same position of the workpiece can be reduced. As a result, the laser welding apparatus can carry out welding for the workpiece with excellent heat balance. Further, because the number of the irradiation on the almost same position of the workpiece is reduced without lengthening the period of the pulse of the laser beam, a time necessary for the welding work is not prolonged. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser welding apparatus and a laser welding method for performing welding by irradiating a workpiece with a laser beam.

  Conventionally, for example, in package sealing of optical device elements and hydrogen vibrators, the lid is welded to the package (ie, laser welding) by irradiating the lid with a laser beam. It has been broken.

  For example, in Patent Document 1, when laser welding a rectangular case in which a power generation element or the like is housed and a lid plate, first, temporary welding is performed at a predetermined location, and then a workpiece (rectangular case and lid plate). Describes a technique for sealing a rectangular case and a cover plate by irradiating a laser beam while moving a table on which is mounted by a predetermined amount. Further, in Patent Document 2, a plurality of workpieces are arranged on a table, and welding is performed by changing the position of irradiating a laser beam on one workpiece by controlling a galvanometer mirror or the like. A technique for moving to the next workpiece and performing the welding operation after the welding operation is completed is described.

  Here, in the technique described in the above-mentioned patent document, the laser beam is irradiated onto the workpiece at a predetermined pulse period, and the position at which one workpiece is irradiated with the laser beam is determined by a predetermined amount for each pulse period. It is moved and welded. Specifically, the minute distance is moved such that the position where the previous irradiation is performed and the position where the next irradiation is performed partially overlap each other. In one work, the distance that can move the position where the laser beam is irradiated during the pulse period is limited, so the time required to move to the next irradiation position is shortened, that is, the pulse period is shortened. As a result, the work time required for welding one workpiece has been shortened.

JP-A-8-315790 JP 2000-164095 A

  However, when welding is performed by the above-described method in order to shorten the work time, a laser beam is irradiated to a single work in a concentrated manner in a short period of time. In some cases, the temperature of the workpiece itself or the temperature distribution on the workpiece may vary greatly depending on the timing (order) of irradiation. Therefore, for example, the work is not melted at the place where the laser beam was irradiated in the initial stage of the welding operation, and the welding failure occurs such that the work is melted too much at the place where the laser beam was irradiated at the end of the welding work. There was a case.

  In addition, in the technique described in Patent Document 1, first, temporary fixing welding is performed at four locations on the workpiece, which are somewhat distant from each other. However, after the temporary fixing welding is performed, the irradiation positions overlap from a predetermined start position. In order to reduce the time required for the welding operation, welding failure as described above may occur.

  Examples of the problem to be solved by the present invention are as described above. It is an object of the present invention to provide a laser welding apparatus and a laser welding method capable of performing laser welding on a workpiece with good thermal balance without delaying work time.

  According to the first aspect of the present invention, a laser welding apparatus that performs welding by irradiating a workpiece with a laser beam includes laser beam emitting means for emitting the laser beam at a predetermined pulse period, and for each pulse period. Irradiating position changing means for changing the position where the workpiece is irradiated with the laser beam, and the irradiation position changing means prevents the laser beam from being irradiated in the vicinity of the position irradiated with the laser beam. In addition, the laser beam irradiation position is changed.

  In a fifth aspect of the present invention, a laser welding method for performing welding by irradiating a workpiece with a laser beam includes a laser beam emitting step of emitting the laser beam at a predetermined pulse period, and for each pulse period. An irradiation position changing step of changing a position at which the workpiece is irradiated with the laser beam. In the irradiation position changing step, the laser beam is not irradiated continuously in the vicinity of the position irradiated with the laser beam. In addition, the laser beam irradiation position is changed.

  In a preferred embodiment of the present invention, a laser welding apparatus that performs welding by irradiating a workpiece with a laser beam includes laser beam emitting means for emitting the laser beam at a predetermined pulse period, and for each pulse period. Irradiating position changing means for changing the position where the workpiece is irradiated with the laser beam, and the irradiation position changing means prevents the laser beam from being irradiated in the vicinity of the position irradiated with the laser beam. Further, the position where the laser beam is irradiated is changed.

  The above laser welding apparatus is preferably used when, for example, a package in which a crystal device or the like is stored and a lid are welded. The laser welding apparatus includes laser beam emitting means for emitting the laser beam at a predetermined pulse period, and performs welding by irradiating the workpiece with the laser beam. Specifically, the laser welding apparatus performs welding by irradiating the workpiece with the laser beam while changing the position where the laser beam is irradiated by the irradiation position changing unit. In this case, the irradiation position changing means changes the position where the laser beam is irradiated so that the laser beam is not irradiated continuously every predetermined pulse in the vicinity of the position where the laser beam is irradiated. In other words, the irradiation position changing means prevents the laser beam from being irradiated continuously at substantially the same location on the workpiece. As a result, according to the laser irradiation apparatus, the number of times the laser beam is irradiated per unit time on almost the same part of the workpiece is reduced, so that the temperature of the workpiece can be effectively increased to a temperature at which the laser beam is appropriately melted. The temperature of the workpiece can be prevented from rising to a high temperature at which excessive melting occurs. That is, according to said laser welding apparatus, welding with respect to a workpiece | work can be performed with sufficient heat balance.

  Furthermore, in the laser welding apparatus described above, the number of times of irradiating the laser beam per unit time to the substantially same part of the work is reduced without increasing the pulse period of the laser beam, and the laser is applied to the entire work per unit time. Since the number of times of beam irradiation has not decreased, the time required for welding work is not delayed.

  In one aspect of the above laser welding apparatus, the irradiation position changing unit irradiates the laser beam so that the laser beam is irradiated to a position separated by a predetermined distance or more on the workpiece for each predetermined pulse. Change the position.

  In this aspect, the laser welding apparatus may irradiate the laser beam at a position separated by a predetermined distance or more on the workpiece for each pulse period, that is, irradiate the laser beam next time to a position separated from the previously irradiated position. it can. Thereby, the heat by a laser beam can be effectively conducted on a workpiece | work, and appropriate welding can be performed.

  In another aspect of the laser welding apparatus, the irradiation position changing unit may prevent the laser beam from being irradiated in the immediate vicinity of the position irradiated with the laser beam until a predetermined period of the pulse period elapses. The position where the laser beam is irradiated is changed.

  In this aspect, the laser welding apparatus can prevent the laser beam from being irradiated in the immediate vicinity of the position irradiated with the laser beam until a predetermined period of the pulse period elapses. Thereby, the vicinity of the position irradiated with the laser beam last time can be maintained at a temperature at which the workpiece is appropriately melted.

  In one suitable example, the said irradiation position change means can be comprised with a galvanometer mirror. Thereby, the position which irradiates a laser beam with respect to a workpiece | work can be changed rapidly with sufficient precision.

  In another embodiment of the present invention, a laser welding method for performing welding by irradiating a workpiece with a laser beam includes a laser beam emitting step of emitting the laser beam at a predetermined pulse period, and for each pulse period. An irradiation position changing step of changing a position at which the workpiece is irradiated with the laser beam. In the irradiation position changing step, the laser beam is not irradiated continuously in the vicinity of the position irradiated with the laser beam. Further, the position where the laser beam is irradiated is changed. Also by the laser welding method described above, it is possible to perform welding on the workpiece with a good thermal balance without delaying the time required for the welding operation.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Configuration of laser welding equipment]
First, a schematic configuration of a laser welding apparatus 100 according to the present invention will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a schematic configuration of a laser welding apparatus 100. The laser welding apparatus 100 mainly includes a laser beam emitting device 1, a controller 2, and a table 3. The laser welding apparatus 100 is an apparatus that performs welding on the workpiece 10 disposed on the table 3.

  Here, a basic configuration of the workpiece 10 will be described with reference to FIG. FIG. 2 is a perspective view showing an example of the workpiece 10. The workpiece 10 includes a package 10b in which a crystal device 10c (for example, a crystal resonator or a crystal filter) is accommodated, and a lid 10a. In the work 10, first, an operation of moving the lid 10a in the direction indicated by the arrow B on the upper portion of the package 10b is performed, and in this state, an operation of welding the lid 10a and the package 10b by the laser welding apparatus 100 is performed. Is called. The lid 10a can be made of a material such as ceramic or metal, and the package 10b can be made of a material such as ceramic.

  Returning to FIG. 1, the configuration of the laser welding apparatus 100 will be described. The laser beam emitting device 1 emits a laser beam LB to the workpiece 10. The laser beam emitting apparatus 1 performs welding by irradiating the lid 10a of the workpiece 10 with the laser beam LB. Specifically, the laser beam emitting apparatus 1 performs welding by irradiating the laser beam LB onto the lid 10a and forming a beam spot on the lid 10a. Further, the laser beam emitting device 1 oscillates the laser beam LB at a predetermined pulse period, and changes the position of the laser beam LB irradiated on the lid 10a every time the laser beam LB is oscillated. As a result, the laser beam LB is irradiated on all the places to be welded on the lid 10a, so that the lid 10a and the package 10b are completely sealed to form an airtight container.

  The controller 2 supplies a control signal S for controlling the laser beam emitting apparatus 1 and controls the laser beam emitting apparatus 1. Specifically, the control signal S includes information on the laser power and pulse period of the laser beam LB to be emitted by the laser beam emitting device 1, information indicating the position where the laser beam LB is to be irradiated on the lid 10a, and the like. include. Therefore, when the controller 2 supplies the control signal S to the laser beam emitting device 1, settings such as the laser power and pulse period of the laser beam LB are changed, and the position where the laser beam LB is irradiated onto the lid 10a. Is changed.

  In FIG. 1, for convenience of explanation, only one workpiece 10 to be welded is displayed, but actually, a plurality of workpieces 10 are arranged on the table 3, and the laser welding apparatus 100 is A welding operation is performed on the plurality of workpieces 10.

[Configuration of laser beam emitting device]
Next, a specific configuration of the laser beam emitting apparatus 1 will be described with reference to FIG. FIG. 3 shows a perspective view of the laser beam emitting apparatus 1.

  The laser beam emitting device 1 mainly includes a laser oscillator L, a beam expander BE, galvanometer mirrors GM1 and GM2, driving devices 4 and 5, and an fθ lens 6. The laser beam emitting device 1 functions as a laser beam emitting unit.

  The laser oscillator L oscillates the laser beam LB at a predetermined pulse period and emits the laser beam LB to the beam expander BE. The beam expander BE adjusts the diameter of the laser beam LB and the like, and emits the adjusted laser beam LB to the galvanometer mirror GM1.

  The galvanometer mirror GM1 is rotated in the direction indicated by the arrow R1 by the driving device 4 to change the direction in which the laser beam LB is reflected. The laser beam LB reflected by the galvanometer mirror GM1 is incident on the galvanometer mirror GM2. The galvanometer mirror GM2 is rotated in the direction indicated by the arrow R2 by the driving device 5 to change the direction in which the laser beam LB is reflected. The laser beam LB reflected by the galvanometer mirror GM2 is incident on the fθ lens 6. Thus, the galvanometer mirrors GM1 and GM2 control the deflection of the incident light beam LB. Further, as described above, the position at which the laser beam LB is incident on the fθ lens 6 is changed by rotating the galvanometer mirror GM1 and the galvanometer mirror GM2. The driving devices 4 and 5 are controlled by a control signal S supplied from the controller 2.

  The fθ lens 6 irradiates the incident laser beam LB perpendicularly to the surface of the lid 10a. That is, the fθ lens 6 emits the laser beam LB from the incident position in a direction perpendicular to the surface of the lid 10a regardless of the incident angle of the laser beam LB. Specifically, as shown in FIG. 3, the fθ lens 6 emits laser beams LB1 to LB3 perpendicular to the surface of the lid 10a. As described above, when the galvanometer mirror GM1 and the galvanometer mirror GM2 are rotated, the position at which the laser beam LB enters the fθ lens 6 is changed. Therefore, by controlling the galvanometer mirror GM1 and the galvanometer mirror GM2, the position where the laser beam LB is irradiated onto the lid 10a is also changed. For example, the irradiation position of the laser beam LB in the lid 10a is moved in one direction by fixing the galvanometer mirror GM2 and rotating the galvanometer mirror GM1, and the laser in the lid 10a by fixing the galvanometer mirror GM1 and rotating the galvanometer mirror GM2. The irradiation position of the beam LB moves in a direction perpendicular to the above direction. As described above, the controller 2 functions as an irradiation position changing unit that changes the irradiation position of the laser beam LB on the lid 10a by controlling the galvanometer mirrors GM1 and GM2.

  Next, a general laser welding method for performing welding by irradiating the workpiece 10 with the laser beam LB will be described with reference to FIG. FIGS. 4A and 4B are plan views of the lid 10a of the workpiece 10 (views from above).

  FIG. 4A shows the order of irradiating the workpiece 10 with the laser beam LB in a general laser welding method. A laser beam LB emitted from the laser beam emitting apparatus 1 is irradiated on the lid 10a of the work 10, and a beam spot SP is formed. In this case, the laser beam emitting apparatus 1 oscillates the laser beam LB with a predetermined pulse period, and moves the position where the laser beam LB is irradiated by a predetermined amount for each pulse period. Specifically, the irradiation position of the laser beam LB on the lid 10a is changed by rotating the galvanometer mirrors GM1 and GM2 in the laser beam emitting apparatus 1. Specifically, the laser beam emitting apparatus 1 irradiates the lid 10a with the laser beam LB so that adjacent beam spots SP partially overlap each other. In this case, the laser beam emitting device 1 first irradiates the lid 10a with the laser beam LB at the position shown in the lower left of FIG. 4A, and counterclockwise as indicated by arrows E1 to E4 from this position, The irradiation position is changed one after another, and the lid 10a and the package 10b are welded.

  In FIG. 4, the laser beam emitting apparatus 1 is set as follows. The laser beam emitting apparatus 1 irradiates the laser beam LB on the outline of a square region of 2 mm in length × 2 mm in width on the lid 10a (that is, the back side of the lid 10a in contact with the edge of the opening of the package 10b). The pulse period of the laser beam LB is 0.002 seconds (s), the interval between the beam spots SP is 0.1 mm, and the total number of spots irradiated to the lid 10a is 80. It is assumed that the above pulse period is relatively short, in other words, the number of pulses oscillated per unit time is large.

  FIG. 4B shows an example of how the lid 10a is melted when welding to the workpiece 10 is completed by the irradiation sequence as shown in FIG. 4A and the setting of the laser beam emitting device 1 as described above. FIG. A hatched portion indicates a region where the lid 10a is melted. The broken line area A1 is a part irradiated with the laser beam LB at the initial stage of the welding work, the broken line area A2 is a part irradiated with the laser beam LB on the middle part of the welding work, and the broken line area A3 is at the final stage of the welding work. This is a portion irradiated with the laser beam LB. Specifically, it can be seen that the broken line area A1 has a smaller melting area than the broken line area A2, and the broken line area A3 has a larger melting area than the broken line area A2. In this case, the lid 10a is appropriately melted in the broken line area A2, but the lid 10a is not completely melted in the broken line area A1, and the lid 10a is too melted in the broken line area A3. Therefore, the strength of welding between the lid 10a and the package 10b may be insufficient in the broken line area A1, and a through hole may be formed in the lid 10a in the broken line area A3.

  Here, the reason why the welding failure as shown by the broken line area A1 and the broken line area A3 occurs in the lid 10a will be described. In the broken line area A1, since the temperature of the lid 10a itself has not sufficiently increased by the irradiation of the laser beam LB, there is a possibility that the lid 10a is not melted by the irradiation of the laser beam LB. Specifically, since the laser beam LB is irradiated on the lid 10a in a short time, the next laser beam LB is irradiated before the heat from the laser beam LB irradiated so far is conducted to the vicinity of the irradiation position. It is thought that this phenomenon occurs because of this.

  On the other hand, in the broken line area A3, when the laser beam LB is irradiated, the lid 10a is already at a high temperature, and since the laser beam LB is irradiated to the lid 10a in this state, an overmelting phenomenon occurs. there is a possibility. Specifically, since the laser beam LB was irradiated on the lid 10a in a short time, the heat generated by the laser beam LB irradiated so far was accumulated without being appropriately released to the outside. It is thought that a strange phenomenon has occurred.

  As described above, in the general laser welding method, since the pulse period of the laser beam emitting device 1 is short and the moving distance of the irradiation position of the laser beam LB is also short, it takes a short time for substantially the same location on the lid 10a. The laser beam LB is irradiated in a concentrated manner. Therefore, in the lid 10a, poor welding such as insufficient melting or excessive melting may occur. In order not to cause such welding defects, simply, in order to perform appropriate welding, the pulse period of the laser beam LB may be lengthened (in other words, the number of times of irradiation to the lid 10a may be reduced). However, this will increase the time required for the welding operation. Therefore, the laser welding apparatus 100 according to the present embodiment executes a laser welding method in which appropriate welding is performed without delaying the time required for welding work.

[Laser welding method]
Next, a laser welding method executed by the laser welding apparatus 100 according to the present embodiment will be described.

  First, the basic concept of the laser welding method according to the present embodiment will be described. As described above, when welding is performed by irradiating the laser beam LB in a short time with respect to substantially the same location on the lid 10a, a welding failure may occur. Therefore, in the laser welding method according to the present embodiment, in the lid 10a, the laser beam LB is not continuously irradiated in the vicinity of the position irradiated with the laser beam LB for each pulse period. Specifically, the laser beam emitting apparatus 1 irradiates the laser beam LB at a position separated by a predetermined distance or more on the lid 10a for each pulse period (irradiates the next laser beam LB to a position away from the previously irradiated position. The position where the laser beam LB is irradiated continuously is not overlapped. Then, after a predetermined period of the pulse period has passed, the laser beam LB is irradiated so that a part of the beam spot SP overlaps in the immediate vicinity of the position irradiated with the laser beam LB until the previous time.

  As described above, according to the laser welding method according to the present embodiment, the number of times the laser beam LB is irradiated per unit time on the substantially same portion of the lid 10a is decreased. Therefore, the temperature of the lid 10a is appropriately set by the laser beam LB. The temperature can be effectively increased to a temperature at which melting occurs, and the temperature of the lid 10a can be prevented from rising to a high temperature at which excessive melting occurs. Therefore, according to the laser welding method according to the present embodiment, welding can be performed with a good heat balance without causing poor welding.

  Further, in the laser welding method according to the present embodiment, the laser beam LB is irradiated at substantially the same location on the lid 10a per unit time without setting to increase the pulse period of the laser beam LB (in other words, to reduce the number of pulses). The number of times to do is reduced. Therefore, in comparison with the configuration according to the comparative example shown in FIG. 4, in the laser welding method according to the present embodiment, the number of times of irradiation per unit time on substantially the same portion on the lid 10a is reduced, but the lid 10a. Since the number of times of irradiation per unit time itself has not decreased, the time required for welding work does not change.

  Next, a specific example of the laser welding method according to the present embodiment will be described with reference to FIGS. 5 to 7 show plan views (views from above) of the lid 10a, and show the beam spots SP formed on the lid 10a.

  FIG. 5 is a diagram illustrating an example of a laser welding method according to the present embodiment. FIG. 5A shows the order in which the laser beam emitting device 1 irradiates the lid 10a with the laser beam LB. In this case, the laser beam emitting device 1 first irradiates the four corners of the lid 10a with the laser beam LB, and the four sides of the lid 10a including the beam spots SP formed at these four corners. Specifically, the four sides of the outline of the square region to be irradiated with the laser beam LB are successively irradiated with the laser beam LB, and the four sides are simultaneously advanced to perform welding. That is, the laser beam emitting device 1 irradiates the laser beam LB at a distant position without irradiating the next laser beam LB in the vicinity of the position irradiated with the previous laser beam LB every pulse period.

  Specifically, the laser beam emitting apparatus 1 first irradiates the laser beam LB first on the lower left of the lid 10a, secondly irradiates the laser beam LB on the lower right, and thirdly irradiates the laser beam LB on the upper right. Irradiation is performed, and the laser beam LB is irradiated fourth in the upper left. That is, the laser beam emitting apparatus 1 first irradiates the laser beam LB one after another to the four corners of the lid 10a. Next, the laser beam emitting apparatus 1 returns (in this case, four pulse periods have elapsed), and the laser beam is fifth in the immediate vicinity of the position irradiated to the lid 10a first. The LB is irradiated, and similarly, the laser beam LB is irradiated in the sixth to eighth positions in the immediate vicinity of the second to fourth irradiation positions. The laser beam emitting apparatus 1 performs welding by irradiating the laser beam LB from such positions as indicated by arrows F1 to F4. That is, the laser beam emitting device 1 performs welding by irradiating the lid 10a with the laser beam LB in a continuous manner as in the general laser welding method shown in FIG. 4 (that is, the welding of one side is completed). Then, the welding is performed separately and simultaneously on the four sides of the lid 10a, instead of welding the adjacent sides. Therefore, in the laser welding method according to the present embodiment, when the welding on one side is finished, the welding on the other three sides is also almost finished at the same time.

  The driving devices 4 and 5 that drive the galvanometer mirrors GM1 and GM2 can move the irradiation position of the laser beam LB at a maximum of 3000 mm / second (s), and thus one cycle in which the laser beam LB is oscillated. In the meantime, the control of moving the position of the laser beam LB from one corner of the lid 10a to the other corner can be sufficiently realized. For example, if the length of one side of the square region to be welded of the lid 10a is 2 mm and the pulse period is 0.002 seconds (s), the irradiation position is 1000 mm / second (s) in this case. Since it only needs to be moved, it can be said that it is within the control range of the driving devices 4 and 5.

  FIG. 5B is a diagram illustrating an example of a melting state of the lid 10a when welding by the laser welding method described above is completed. A region A5 indicates a region where the lid 10a is melted. Comparing the melting condition of the lid 10a shown in FIG. 5B with the melting condition of the lid 10a by the general laser welding method shown in FIG. 4B (setting of the laser beam emitting device 1 (pulse period and 5 (b), the lid 10a shown in FIG. 5 (b) has a small difference in melting depending on the position on the lid 10a. It can be seen that no melting or the like has occurred. That is, the lid 10a welded by the laser welding method according to the present embodiment is welded with a good thermal balance as a whole.

  In the laser welding method described above, the number of laser beams LB irradiated per unit time to substantially the same location on the lid 10a is reduced. However, the laser beam LB is irradiated to the entire lid 10a per unit time. Since the number of times of welding does not decrease, the time required for the welding operation is almost the same as compared with the general laser welding method shown in FIG.

  FIG. 6 is a view showing another example of the laser welding method according to the present embodiment. In this case, unlike the example shown in FIG. 5, the laser beam emitting apparatus 1 is different in the order of irradiating the laser beam LB to the four corners of the lid 10a. Specifically, the laser beam emitting device 1 first irradiates the laser beam LB first on the lower left of the lid 10a, secondly irradiates the laser beam LB on the upper right, and thirdly irradiates the laser beam LB on the lower right. Irradiation is performed, and the laser beam LB is irradiated fourth in the upper left. Next, the laser beam emitting apparatus 1 returns and irradiates the laser beam LB fifth immediately in the vicinity of the position first irradiated on the lid 10a, and similarly, at the second to fourth positions irradiated. The sixth to eighth laser beams LB are irradiated in the immediate vicinity. Then, the laser beam emitting apparatus 1 performs welding by irradiating the laser beam LB from such positions as indicated by arrows G1 to G4. Also in this case, the laser beam emitting device 1 performs welding separately and simultaneously with respect to the four sides of the lid 10a. Also by executing the laser welding method according to such an irradiation order, the lid 10a can be welded with a good heat balance.

  FIG. 7 is a view showing still another example of the laser welding method according to the present embodiment. In this case, unlike the example shown in FIGS. 5 and 6, the laser beam emitting apparatus 1 does not irradiate the laser beam LB to the four corners of the lid 10a first, and the laser beam is applied to the central part of the four sides of the lid 10a. LB is irradiated, and laser beam LB is sequentially irradiated next to this position to perform welding. Specifically, the laser beam emitting apparatus 1 first irradiates the laser beam LB first on the central portion of the lower side of the lid 10a, and secondly irradiates the laser beam LB on the central portion of the right side of the lid 10a. The laser beam LB is irradiated to the center of the upper side of the lid 10a first, and the laser beam LB is irradiated to the center of the left side of the lid 10a fourth. Next, the laser beam emitting apparatus 1 returns and irradiates the laser beam LB fifth immediately in the vicinity of the position first irradiated on the lid 10a, and similarly, at the second to fourth positions irradiated. The sixth to eighth laser beams LB are irradiated in the immediate vicinity. The laser beam emitting apparatus 1 performs welding by irradiating the laser beam LB from such a position as indicated by arrows H1 to H4. That is, in this example, first, the laser beam LB is irradiated to the central part of the four sides of the lid 10a, and the laser beam LB is successively irradiated next to this position, and finally the laser beam is applied to the central part of the four sides. The welding operation is completed by irradiating the beam LB. Also by executing the laser welding method according to such an irradiation order, the lid 10a can be welded with a good heat balance.

  As described above, in the laser welding method according to the present embodiment, the laser beam LB is irradiated on the lid 10a at a distant position on the lid 10a every pulse period, and in the vicinity of the position irradiated last time. Subsequently, the laser beam LB is not irradiated. As a result, the number of times the laser beam LB is irradiated per unit time on the substantially same portion of the lid 10a is decreased, and the temperature of the lid 10a is effectively increased to a temperature at which proper melting occurs by the laser beam LB. In addition, the temperature of the lid 10a can be prevented from rising to a high temperature at which excessive melting occurs. That is, according to the laser welding method according to the present embodiment, it is possible to perform welding on the lid 10a with a good thermal balance. This makes it possible to perform appropriate welding without causing poor welding.

  In the above description, an example of a laser welding method in which the laser beam LB is first irradiated to a certain distance from the lid 10a and the portions including these four positions are separately and simultaneously welded. Although shown, application of the present invention is not limited to this. For example, the welding may be performed by first irradiating the laser beam LB to the eight positions of the lid 10a (the four corners and the center of the four sides of the lid 10a).

  In addition, the shape of the laser welding target (the lid in the present embodiment) to irradiate the laser beam is not limited to a square or a rectangle. For example, the laser beam LB is irradiated along a circular shape, an elliptical shape, or other curved shapes. The present invention can also be applied to laser welding. When the shape to be irradiated with the laser beam is a shape composed of a plurality of polygonal sides such as a square and a rectangle as in the above-described embodiment, the laser beam is sequentially irradiated to each of the sides constituting the shape. do it. That is, the laser beam LB is not irradiated to the same side in a continuous pulse cycle. In addition, when the laser beam irradiation shape is circular, elliptical, etc., the laser beam irradiation position and order are determined so that the laser beam irradiation position is separated by a predetermined distance or more. do it.

It is a block diagram which shows schematic structure of a laser welding apparatus. It is a perspective view which shows schematic structure of a workpiece | work. It is a figure which shows schematic structure of a laser beam extraction apparatus. It is a figure which shows the general laser welding method. It is a figure which shows an example of the laser welding method which concerns on the Example of this invention. It is a figure which shows an example of the laser welding method which concerns on the Example of this invention. It is a figure which shows an example of the laser welding method which concerns on the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam emission apparatus 2 Controller 3 Table 10 Work 10a Lid 10b Package 100 Laser welding apparatus GM1, GM2 Galvano mirror L Laser oscillator LB Laser beam

Claims (5)

A laser welding apparatus that performs welding by irradiating a workpiece with a laser beam,
Laser beam emitting means for emitting the laser beam at a predetermined pulse period;
Irradiation position changing means for changing the position of irradiating the laser beam to the workpiece for each pulse period,
The irradiation position changing means changes the position where the laser beam is irradiated so that the laser beam is not irradiated in the vicinity of the position irradiated with the laser beam.   The irradiation position changing means changes the position where the laser beam is irradiated so that the laser beam is irradiated to a position separated by a predetermined distance or more on the workpiece for each predetermined pulse. Item 2. The laser welding apparatus according to Item 1.   The irradiation position changing means changes the position of the laser beam irradiation so that the laser beam is not irradiated in the immediate vicinity of the position irradiated with the laser beam until a predetermined period of the pulse period elapses. The laser welding apparatus according to claim 1 or 2.   The laser irradiation apparatus according to any one of claims 1 to 3, wherein the irradiation position changing unit includes a galvanometer mirror. A laser welding method for performing welding by irradiating a workpiece with a laser beam,
A laser beam emitting step of emitting the laser beam at a predetermined pulse period;
An irradiation position changing step for changing a position of irradiating the workpiece with the laser beam for each pulse period; and
In the irradiation position changing step, the laser beam irradiation position is changed so that the laser beam is not irradiated in the vicinity of the position irradiated with the laser beam.

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