JP6718172B2 - Laser welding apparatus and laser welding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laser welding apparatus and a laser welding method for welding two thermoplastic resin sheets with each other by an infrared laser beam.

In the laser welding apparatus and the laser welding method according to the present invention, the heat generated in the vicinity of the irradiation spot of the infrared laser beam is diffused and absorbed by the heat dissipating member constituting the sheet pressing body, so that the welding mark is made of the thermoplastic resin sheet. The welding portion is formed only at the interface between the two thermoplastic resin sheets which are prevented from reaching the surface, but the laser welding is performed while absorbing the heat by the heat radiator. Are known from patent documents 1 to 3.

The sheet pressing body of the laser welding apparatus (production apparatus for a cryopreservation bag) according to Patent Document 1 is made of a solid material that is rich in infrared ray transmitting action and good heat conducting action, and a steel material that supports the radiator. The sheet pressing body has a welding posture in which the heat dissipating body adheres to the thermoplastic resin sheet placed on the sheet table in a stacked state, and the sheet pressing body is attached to the thermoplastic resin sheet. It is configured to be swingable and openable via a hinge between the radiator and the standby position in which the radiator is separated.

In the laser welding method described in Patent Document 2, a plate-shaped heat dissipating material is placed in contact with the surface of the thermoplastic resin sheet on the upper side so that the surface of the thermoplastic resin sheet is irradiated with an infrared laser beam. The generated heat is radiated by the heat radiation material. Further, Patent Document 2 discloses that the compressed heat air is blown from the air duct onto the surface of the heat dissipation material, whereby the heat dissipation effect of the heat dissipation material can be promoted.

In the laser welding device (infrared welding device for thermoplastic resin member) described in Patent Document 3, a heat radiating material (infrared transmissive material) having a shorter or smaller area than the resin sheet along the upper surface of the thermoplastic resin sheet on the upper side is used. Both resin sheets are welded by irradiating an infrared laser beam through the radiator while slidingly moving (solid).

JP, 2016-40078, A JP, 2016-83853, A JP, 2009-184162, A

The problem of the laser welding apparatus or the laser welding method described in Patent Documents 1 and 2 is that the adhesiveness between the thermoplastic resin sheet on the upper side and the radiator disposed above the thermoplastic resin sheet is It is likely to be defective, and the intended heat dissipation effect by the heat radiator cannot be obtained, and as a result, welding marks may extend to the upper surface of the thermoplastic resin sheet. As a method for solving the above problem, for example, it is conceivable that the sheet table is pushed up from below toward the radiator during laser irradiation, or the radiator is pushed down toward above the sheet table during laser irradiation. In this case, it is possible to avoid that the radiator that has been pushed up or pushed down bends like a drum, impairs the flatness, and causes variations in the interface position of the thermoplastic resin sheet between the center part and the peripheral part of the table. As a result, there may occur a problem that the welding property of the thermoplastic resin sheet becomes uneven between the central portion and the peripheral portion.

When the area of the heat radiator is reduced as in Patent Document 3, there is no possibility that the heat radiator will bend, but a mechanism for moving the heat radiator is required, and the laser welding device is inevitably complicated. Further, there is a possibility that a new inconvenience that the thermoplastic resin sheet is displaced due to the movement of the heat radiator may occur, and a mechanism for securely fixing the thermoplastic resin sheets in a two-ply state is required. Has the disadvantage of complicating the structure.

The present invention does not cause a defect such as a welding defect caused by the thermoplastic resin sheet being inadvertently displaced, or a non-uniform welding property due to a large flexural deformation of the radiator, Moreover, it is another object of the present invention to provide a novel laser welding device and a laser welding method in which the heat diffusion and absorption action of the radiator can be more stably exhibited.

The present invention relates to a sheet table 7 for supporting two thermoplastic resin sheets 3 and 4 stacked one above the other, a radiator 13 made of a solid material rich in infrared ray transmitting action and good heat conducting action, and the radiator. A sheet pressing body 8 for holding the thermoplastic resin sheets 3 and 4 placed on the sheet table 7 and a pressing frame 14 supporting the sheet 13; and an infrared laser from above via the sheet pressing body 8. A laser device 5 for irradiating the beam toward the thermoplastic resin sheets 3 and 4, and a scanning structure 6 for moving and operating one of the sheet table 7 and the laser device 5 are provided, and the sheet table 7 and the laser device 5 are provided. A laser welding device that integrates both sheets 3 and 4 by irradiating an infrared laser beam on the interface of the thermoplastic resin sheets 3 and 4 to form a welded portion while relatively moving and with the scanning structure 6 And Then, by injecting a gas onto the upper surface of the radiator 13 of the sheet pressing body 8 located in the vicinity of the irradiation spot 35 of the infrared laser beam by the laser device 5, the thermoplastic resin sheet in the vicinity of the irradiation spot 35. A pressurizing device 36 for locally pressurizing and closely contacting the radiator 13 with respect to 3.4 is provided , and a gas injection region from the pressurizing device 36 on the upper surface of the radiator 13 and the upper surface of the radiator 13. Is set so as not to overlap the irradiation spot 35 of the infrared laser beam by the laser device 5 in FIG. There characterized that you have been configured to be injected.

Specifically, the pressurizing device 36 includes a pressurizing head 38 having a gas injection port 37, and a gas supply mechanism 39 for supplying gas to the pressurizing head 38. The pressurizing head 38 is composed of an air bearing formed in a hollow cylindrical shape having a hollow portion 49. Then, both sheets 3 and 4 are irradiated with the infrared laser beam by the laser device 5 through the hollow portion 49 of the pressurizing head 38, and the gas jet formed on the cylinder end surface of the pressurizing head 38 or the cylinder inner wall surface. The gas can be ejected from the mouth 37 onto the upper surface of the radiator 13 located around the irradiation spot 35.

An elevating mechanism 40 for moving the pressurizing head 38 in the vertical direction is provided, and the elevating mechanism 40 allows the pressurizing head 38 to move up and down relatively with respect to the laser device 5 and the sheet pressing body 8. You can

Further, the present invention is directed to the upper side with respect to the interface between the thermoplastic resin sheets 3 and 4 which are placed in a state where two sheets are stacked between the lower side table 7 and the upper side sheet pressing body 8. A laser welding method for integrating both sheets 3 and 4 by irradiating an infrared laser beam from the above to form a welded portion is targeted. Then, by injecting a gas onto the upper surface of the radiator 13 of the sheet pressing body 8 located in the vicinity of the irradiation spot 35 of the infrared laser beam, the thermoplastic resin sheets 3 and 4 are formed in the vicinity of the irradiation spot 35. while locally by pressure-contact the heat radiator 13 against the thermoplastic resin at the interface between both sheets 3, 4 by heating and melting, and is welded both sheets 3, 4, the upper surface of the heat sink 13 The region where the gas is ejected from the pressurizing device 36 and the irradiation region of the infrared laser beam by the laser device 5 on the upper surface of the radiator 13 are set so as not to overlap with each other, and the entire circumference of the irradiation spot 35 of the infrared laser beam is set. gas from the pressure device 36 against the upper surface of the radiator 13 located is characterized that you have been configured to be injected.

In the present invention, the infrared laser beam is applied to the interface between the thermoplastic resin sheets 3 and 4 while pressing the thermoplastic resin sheets 3 and 4 placed on the sheet table 7 with the sheet pressing body 8 having the radiator 13. Since the welding work is performed by irradiating the heat radiation toward the thermoplastic resin sheet, the thermoplastic resin sheet can be moved along with the movement of the heat radiator as in the conventional form in which the welding work is performed while sliding the heat radiator itself on the thermoplastic resin sheet. There is no room for inconvenience such as displacement, and welding work can be carried out more stably. In addition, since a special fixing structure for fixing only the four corners of the thermoplastic resin sheet is unnecessary, the laser welding apparatus can be simplified and the cost of the laser welding apparatus can be reduced. Further, there is also an advantage that the welding work can be carried out more quickly without the need for a troublesome work such as fixing each of the four corners of the thermoplastic resin sheet.

In addition, in the present invention, the heat radiator 13 of the sheet pressing body 8 located in the vicinity of the irradiation spot 35 of the infrared laser beam is pressed from above, and only in the vicinity of the irradiation spot 35, the thermoplastic resin sheet 3. Since the heat dissipating member 13 is locally adhered to the heat dissipating member 4, the welding work is performed, so that the heat dissipating member 13 is pressed more securely than the heat dissipating member 13 against the thermoplastic resin sheets 3 and 4, for example. The radiator 13 can be brought into close contact with the resin sheet 3. As described above, according to the present invention, the heat diffusion and absorption effect of the radiator 13 on the thermoplastic resin sheets 3 and 4 in the vicinity of the irradiation spot 35 is favorably exhibited, so that the welding marks are formed on the thermoplastic resin sheets 3 and 4. Both sheets 3 and 4 can be welded more stably by reliably preventing the sheet from reaching the surface. It is also possible to suppress the occurrence of welding defects due to the welding traces extending to the surfaces of both sheets 3 and 4. Since it is possible to accurately weld both sheets 3 and 4 by the infrared laser beam, there is also an advantage that the welding strength of both sheets 3 and 4 can be improved.

By injecting the gas, it is possible to locally pressurize and closely contact the radiator 13 located near the irradiation spot 35. According to this, it is possible to locally pressurize the heat radiator 13 without contacting the heat radiator 13 (in a non-contact state). It is possible to obtain a laser welding device or a laser welding method having higher reliability without causing any inconvenience such as damage.

When the gas is jetted onto the upper surface of the radiator 13 located around the irradiation spot 35, the radiator 13 is uniformly heated from the entire periphery of the irradiation spot 35 so as to surround the irradiation spot 35. It becomes possible to press against the plastic resin sheets 3 and 4. As described above, according to the present invention, the radiator 13 can be more reliably pressed against the thermoplastic resin sheets 3 and 4 as compared with the form in which the gas is ejected from only one direction, so that the occurrence of welding failure is more reliable. Can be reduced to

When the pressing head 38 is configured to be vertically movable relative to the laser device 5 and the sheet pressing body 8 by the elevating mechanism 40, the pressing head 38 is vertically moved to move the pressing head 38 to the sheet pressing body 8. By changing the facing distance, it is possible to adjust the pressure applied to the heat radiator 13 and the close contact of the heat radiator 13 to the thermoplastic resin sheets 3 and 4 in a large or small manner. From the above, according to the present invention, it is possible to optimize the pressurization state and the like for the radiator 13 according to various factors such as the thickness dimensions of both sheets 3 and 4, the materials of both sheets 3 and 4, or the surrounding environment. Therefore, it is possible to more reliably suppress the occurrence of defective welding and obtain a highly reliable laser welding apparatus. When the pressurizing head 38 is configured to be vertically movable independently of the laser device 5, the lifting mechanism 40 is simpler than the structure in which the laser device 5 and the pressurizing head 38 are integrally moved up and down. Can be promoted. Since only the pressurizing head 38 moves up and down, it is not necessary to change the focus position of the infrared laser beam emitted from the laser device 5 as the pressurizing head 38 moves up and down. It is also excellent in that it is easy to control.

It is a longitudinal section front view of the important section of the laser welding equipment concerning a 1st embodiment of the present invention. It is a schematic block diagram of the laser welding apparatus which concerns on this invention. It is a figure for demonstrating rocking|fluctuation opening/closing operation|movement of the sheet pressing body which comprises the laser welding apparatus which concerns on this invention. It is a figure for demonstrating the up-and-down operation|movement of the pressurizing device which comprises the laser welding apparatus which concerns on this invention. It is the sectional view on the AA line of FIG. It is a vertical front view of the principal part of the laser welding device concerning a 2nd embodiment of the present invention.

(First embodiment)
1 to 5 show a first embodiment in which the laser welding apparatus and the laser welding method of the present invention are applied to a manufacturing apparatus for a cryopreservation bag and a manufacturing method for a cryopreservation bag. The front/rear, left/right, and top/bottom in the present embodiment refer to the cross arrows shown in FIGS.

2 to 4, a cryopreservation bag manufacturing apparatus includes a base 1, a sheet fixing structure 2 provided on the base 1, and two stacked thermoplastic resin sheets supported by the sheet fixing structure 2 ( Hereinafter, referred to as "resin sheet".) A laser device 5 for irradiating an infrared laser beam toward 3 and 4, a scanning structure 6 for moving and operating the sheet fixing structure 2 with respect to the infrared laser beam, and the like. ..

The resin sheets 3 and 4 are transparent sheets made of any one of a fully fluorinated resin, a partially fluorinated resin, and a fluorinated resin copolymer. Specific forming materials include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), and tetrafluorine. Examples thereof include ethylene oxide/hexafluoropropylene copolymer (FEP), ethylene/tetrafluoroethylene copolymer (ETFE), and chlorotrifluoroethylene copolymer (ECTFE). In this example, two resin sheets 3 and 4 made of a tetrafluoroethylene/hexafluoropropylene copolymer having a thickness of 100 μm were welded to form a cryopreservation bag.

The sheet fixing structure 2 includes a rectangular long rectangular seat table 7 that supports two resin sheets 3 and 4, and a sheet pressing body that holds and holds the resin sheets 3 and 4 placed on the sheet table 7. 8 and. The seat table 7 includes a table body 10 made of aluminum having high thermal conductivity, and a table base 11 that fixedly supports the table body 10. A hinge 17 described later is attached to the left and right of the rear end of the table base 11. A bracket 12 for doing this is provided so as to project upward (see FIG. 3). The upper surface (mounting surface) of the table body 10 on which the resin sheets 3 and 4 are mounted is configured as a flush horizontal surface.

The sheet pressing body 8 includes a heat radiating body 13 made of a solid material rich in infrared ray transmitting action and good heat conducting action, and a steel pressing frame 14 supporting the heat radiating body 13. As the solid material for forming the radiator 13, any infrared transparent radiator such as zinc selenide, zinc sulfide, silicon or germanium, which is transparent to an infrared laser, is used because the carbon dioxide laser is used for welding. However, in this embodiment, the radiator 13 is formed of a single crystal silicon disk. As shown in FIG. 5, the pressing frame 14 is composed of an octagonal metal frame body wider than the seat table 7, a circular laser window 15 is opened in the center thereof, and a circular mounting seat 16 is provided on the lower surface side of the window 15. Has been formed. The radiator 13 is fitted and mounted on the mounting seat 16 and fixed by an adhesive. As shown in FIG. 4, the upper surface of the radiator 13 is located below the upper surface of the pressing frame 14, and a step is formed between the upper surfaces.

By connecting the rear portion of the pressing frame 14 and the bracket 12 of the table base 11 with a pair of left and right hinges 17, the entire sheet pressing body 8 is supported by the sheet table 7 so as to be vertically swingable and openable. As shown in FIGS. 2 and 4, the sheet pressing body 8 can be displaced between a welding position facing the sheet table 7 and a standby position in which it is lifted upward and tilted backward as shown in FIG. In the state where the sheet pressing body 8 is in the welding posture, a part of the heat radiator 13 protrudes from the left and right side edges of the sheet table 7 (see FIG. 4 ). In order to facilitate the opening/closing operation of the sheet pressing body 8, a handle 18 is provided at the center of the front portion of the pressing frame 14. Further, the rubber block 19 provided at the center of the rear portion of the sheet pressing body 8 is received by the stopper 20 fixed to the bracket 12, so that the sheet pressing body 8 operated to open in the standby position is positioned in the backward tilted position. It is supposed to be retained. In this manner, with the sheet pressing body 8 in the standby position, the two stacked resin sheets 3 and 4 are placed on the table body 10, or the blank body of the cryopreservation bag that has been welded is placed on the table. It can be taken out from the main body 10.

The laser device 5 is a commercially available carbon dioxide gas laser unit, and includes a laser box 22 fixed on the base 1 to irradiate laser light, an irradiation tube 23 protruding from a side end of the laser box 22, Inside the projection end of the irradiation tube 23, inside the deflection mirror 24 that redirects the laser light output from the resonator of the laser box 22 downward, and inside the laser head 25 provided below the irradiation tube 23. And a laser nozzle 27 that is provided at the lower end of the laser head 25 and that irradiates the laser light focused by the condenser lens 26 toward the resin sheets 3 and 4 on the sheet table 7. Composed of.

The scanning structure 6 is configured as an XY stage by a Y-axis slider 29 fixed on the base 1 and an X-axis slider 31 fixed on a moving table 30 of the Y-axis slider 29. The Y-axis slider 29 and the X-axis slider 31 are each composed of a commercially available ball screw type electric slider (actuator), and are arranged in a state of being orthogonal to each other. The table base 11 of the seat table 7 is fixed to the moving table 32 of the X-axis slider 31. In this way, by supporting the table base 11 by the XY stage provided on the base 1, the table body 10 can be freely displaced with respect to the laser nozzle 27. Accordingly, while the moving tables 30 and 32 of the Y-axis slider 29 and the X-axis slider 31 are moved and operated according to the preset XY coordinates, the resin sheets 3 and 4 are irradiated with the infrared laser beam, so that both sheets 3 are A weld bead having an arbitrary shape can be formed at the interface of 4. In FIG. 2, reference numeral 33 indicates a control device for controlling the operating states of the laser device 5, the scanning structure 6, and a pressurizing device 36 described later.

As shown in FIG. 1 and FIG. 2, the radiator 13 is pressed from underneath the laser nozzle 27 of the laser device 5 from above so that the resin sheets 3 and 4 (especially above) are irradiated in the vicinity of the irradiation spot 35. A pressure device 36 for locally pressing and closely contacting the radiator 13 with the resin sheet 3) is provided. The pressurizing device 36 includes a pressurizing head 38 having a gas injection port 37, a gas supply mechanism 39 that supplies gas to the pressurizing head 38, and an elevating mechanism 40 that moves the pressurizing head 38 in the vertical direction. It The elevating mechanism 40 includes a bracket 41 provided below the laser box 22, a ball screw type electric slider (actuator) 42 fixed to the free end side of the bracket 41, a moving table 43 of the electric slider 42, and the like. To be done. A head support arm 44 is cantilevered and fixed to the moving table 43, and a pressure head 38 is fixed to a free end of the head support arm 44 via a beam guide 45. By the lifting mechanism 40, the pressurizing head 38 is positioned at a lower position (see FIG. 1) facing the upper surface of the radiator 13 with a space of a few microns between them, and a few centimeters to several tens of inches from the upper surface of the radiator 13. It can move up and down with an upper position (see Fig. 2) that is a centimeter apart.

The beam guide 45 is a molded product integrally formed with a hollow cylindrical guide main body 47 having a hollow portion 46 at the center and flanges provided at the upper and lower ends of the guide main body 47, which are long in the vertical direction. The pressing head 38 is fixed to the lower flange by screws 48. The pressurizing head 38 has a hollow cylindrical housing 50 having a hollow portion 49 at its center, an air chamber 51 provided inside the housing 50, and a ring-shaped opening at the cylindrical end surface of the housing 50. The air bearing is composed of the gas injection port 37 and the porous body 53 attached to the gas injection port 37, and the gas introduction port 54 is provided at one location on the outer surface of the cylinder of the housing 50.

The gas supply mechanism 39 for supplying gas to the pressurizing head 38 is a hose which is a compressor 55 (see FIG. 2) that generates compressed air and an air flow path that is arranged between the compressor 55 and the gas introduction port 54. And 56. The hose 56 is made of a flexible material so that it can follow the vertical movement of the pressurizing head 38 caused by the operation of the elevating mechanism 40. Reference numeral 57 indicates an adapter for the hose 56 attached to the gas introduction port 54. The compressed air generated by the compressor 55 is sent to the air chamber 51 of the pressurizing head 38 via the hose 56 and the gas introduction port 54, and is directed downward from the ring-shaped gas injection port 37 opened on the cylinder end surface. Is jetted. The beam guide 45 is arranged directly below the laser device 5, and the infrared laser beam emitted from the laser device 5 passes through the hollow cylindrical portion of the beam guide 45 and the hollow cylindrical portion of the pressurizing head 38 and radiates heat. After passing through the body 13, the interface between the resin sheets 3 and 4 is irradiated. From the above, as shown in FIG. 1, the air jetted from the gas jet port 37 can press the radiator 13 located around the entire irradiation spot 35 of the infrared laser beam from the laser device 5 from above. .. Further, in the vicinity of the irradiation spot 35, the radiator 13 can be locally pressed and adhered to the upper resin sheet 3.

The manufacturing procedure of the cryopreservation bag will be described below. In the laser device 5, focus adjustment of the condenser lens 26 is performed in advance so that the infrared laser beam is focused at the interface between the two resin sheets 3 and 4 that are stacked. As shown in FIG. 3, after the sheet pressing body 8 is opened to the standby position, the resin sheets 3 and 4 are placed in the center of the table body 10. At this time, the resin sheets 3 and 4 are positioned such that their long sides are parallel to the center of the Y-axis slider 29 and the centers of the resin sheets 3 and 4 are aligned with the center of the table body 10. The sheet pressing body 8 is swung downward to be in the welding posture. In this state, the resin sheets 3 and 4 are in close contact with the table body 10 due to the weight of the pressing frame 14 and the radiator 13. Further, the pressure device 36 is located at an upper position apart from the radiator 13 (see FIG. 2).

When the above welding preparation work is completed, the scanning structure 6 is operated to match the welding start position with the irradiation position of the infrared laser beam, and then the elevating mechanism 40 is operated to lower the pressure device 36 to the lower position, The pressurizing device 36 is located a few microns above the radiator 13 (see FIG. 1). Next, the gas supply mechanism 39 is operated to inject gas from the gas injection port 37 of the pressurizing head 38 toward the upper surface of the radiator 13, and the radiator 13 around the entire irradiation spot 35 is moved downward. While pushing down, the laser device 5 and the scanning structure 6 are operated to form a bead in a single stroke on the interface between the resin sheets 3 and 4. At this time, since the radiator 13 transmits the infrared laser, the radiator 13 does not absorb the infrared laser and generate heat. Further, when forming the bead, the heat of welding is conducted around the bead forming position, but it is generated by being absorbed in the vicinity of the surface of the resin sheet 3 by the laser energy reaching the surface of the resin sheet 3 on the upper side. The heat is absorbed and diffused by the radiator 13 having excellent thermal conductivity. At this time, since the heat radiator 13 located in the vicinity of the irradiation spot 35 is locally pressed against the resin sheets 3 and 4 (more specifically, the resin sheet 3 on the upper side) by the pressure device 36, The degree of adhesion of 13 to the resin sheet 3 can be improved, and the heat diffusion and absorption action of the radiator 13 can be more reliably exhibited. As described above, only the interface between the resin sheets 3 and 4 is welded, and the surface condition of both sheets 3 and 4 can be maintained in a smooth state.

When the welding work by the infrared laser is completed as described above, the sheet pressing body 8 is opened to the standby position, and the blank body of the cryopreservation bag on the table body 10 is taken out. After that, by repeating the above-mentioned work, the blank body of the bag can be manufactured.

As described above, in the cryopreservation bag manufacturing apparatus according to the present embodiment, the infrared laser beam is applied while pressing the thermoplastic resin sheets 3 and 4 placed on the sheet table 7 with the sheet pressing body 8. Since the welding work is performed by irradiating toward the interface between the thermoplastic resin sheets 3 and 4, for example, as in the conventional embodiment in which the welding work is performed while sliding the radiator itself on the thermoplastic resin sheet, There is no room for the inconvenience that the thermoplastic resin sheet shifts with the movement of the heat radiator, and the welding operation can proceed more stably.

The radiator 13 of the sheet pressing body 8 located in the vicinity of the irradiation spot 35 of the infrared laser beam is pressed from above, and the radiator 13 is pressed against the thermoplastic resin sheets 3 and 4 only in the vicinity of the irradiation spot 35. Since the welding work can be carried out while locally adhering to the thermoplastic resin sheet 3, the heat radiation to the thermoplastic resin sheet 3 can be performed more reliably as compared with a configuration in which the entire radiator 13 is pressed against the thermoplastic resin sheets 3 and 4, for example. The body 13 can be closely attached. From the above, the heat diffusion and absorption effect of the radiator 13 on the thermoplastic resin sheets 3 and 4 in the vicinity of the irradiation spot 35 is favorably exerted, so that it is ensured that the welding marks extend to the surface of the thermoplastic resin sheets 3 and 4. It is possible to more stably weld both sheets 3 and 4 by suppressing the above. It is also possible to suppress the occurrence of welding defects due to the welding traces reaching the surfaces of both sheets 3 and 4. Since it is possible to accurately weld both sheets 3 and 4 by the infrared laser beam, it is possible to improve the welding strength of both sheets 3 and 4.

Since the gas is ejected onto the upper surface of the radiator 13 located around the irradiation spot 35, the radiator 13 is evenly arranged from the entire periphery of the irradiation spot 35 so as to surround the irradiation spot 35. It can be pressed against the thermoplastic resin sheets 3 and 4. Therefore, it is possible to more surely press the radiator 13 against the thermoplastic resin sheets 3 and 4 as compared with the case where the gas is ejected from only one direction, and it is possible to suppress the occurrence of defective welding.

Since the pressing head 38 is configured to be movable up and down, the pressing head 38 is moved up and down to change the facing distance between the pressing member 8 and the sheet pressing body 8 so that the pressing state with respect to the heat radiating body 13 and the heat radiating body 13 are reduced. The close contact state with the thermoplastic resin sheets 3 and 4 can be adjusted to be large or small. Therefore, the pressure applied to the radiator 13 can be optimized according to various factors such as the thickness dimensions of the both sheets 3 and 4, the materials of the both sheets 3 and 4, or the surrounding environment. The occurrence of defective welding can be suppressed. Since the pressurizing head 38 can be moved up and down independently of the laser device 5, the lifting mechanism 40 can be simplified as compared with the structure in which the laser device 5 and the pressurizing head 38 are integrally moved up and down. Can be planned. Since only the pressurizing head 38 moves up and down, it is not necessary to change the focus position of the infrared laser beam emitted from the laser device 5 as the pressurizing head 38 moves up and down. Easy to control.

(Second embodiment)
FIG. 6 shows a second embodiment of the laser welding apparatus according to the present invention. This laser welding device is different from the first embodiment in that the gas injection port 37 is formed on the inner wall surface of the cylinder facing the hollow portion 49 of the pressing head 38. Specifically, in the second embodiment, the gas injection ports 37 are provided at four equally spaced positions on the inner wall surface of the cylinder. Each gas injection port 37 is formed in an inclined posture in which the inlet side facing the air chamber 51 is located above and the outlet side facing the hollow portion 49 is located below, and the gas sent into the air chamber 51 is The gas is jetted downward from the hollow portion 49 along each gas jet 37. Since the other shapes are the same as those in the first embodiment, the same members are designated by the same reference numerals and the description thereof will be omitted.

In the above-described embodiment, the pressurizing head 38 is configured by the hollow cylindrical housing 50 including the air chamber 51, but it is not necessary, and the point is that the pressing head 38 is provided with respect to the upper surface of the radiator 13 in the vicinity of the irradiation spot 35. It is sufficient that the radiator 13 can be pressed against the resin sheets 3 and 4 by injecting the gas, and the invention is not limited to the air bearing. The structures of the scanning structure 6, the sheet pressing body 8, the lifting mechanism 40, etc. are not limited to those shown in the embodiment.

2 Sheet fixing structure 3 Thermoplastic resin sheet (top)
4 Thermoplastic resin sheet (bottom)
5 Laser Device 6 Scanning Structure 7 Sheet Table 13 Heat Dissipator 14 Pressing Frame 35 Irradiation Spot 36 Pressurizing Device 37 Gas Injection Port 38 Pressurizing Head 39 Gas Supply Mechanism 40 Elevating Mechanism 49 Hollow Section

Claims (4)

A sheet table (7) for supporting the two thermoplastic resin sheets (3.4) that are stacked one above the other,
It has a radiator (13) composed of a solid material rich in infrared ray transmitting action and good heat conducting action, and a pressing frame (14) supporting the radiator (13), and is mounted on a sheet table (7). A sheet pressing body (8) for holding and holding the placed thermoplastic resin sheet (3.4);
A laser device (5) for irradiating the thermoplastic resin sheet (3.4) with an infrared laser beam from above through the sheet pressing body (8);
A scanning structure (6) for moving and operating either the seat table (7) or the laser device (5);
Is equipped with
By irradiating the infrared laser beam on the interface of the thermoplastic resin sheet (3.4) while forming the welded portion while moving the sheet table (7) and the laser device (5) relative to each other by the scanning structure (6). A laser welding device that integrates both sheets (3.4),
By injecting a gas onto the upper surface of the radiator (13) of the sheet pressing body (8) located in the vicinity of the irradiation spot (35) of the infrared laser beam by the laser device (5), the irradiation spot (35) concerned. in the vicinity of, provided with a pressure device for locally pressurized and adhesion (36) and heat radiator (13) relative to the thermoplastic resin sheet (3, 4),
The injection area of the gas from the pressure device (36) on the upper surface of the radiator (13) and the irradiation spot (35) of the infrared laser beam by the laser device (5) on the upper surface of the radiator (13) do not overlap. And the gas is ejected from the pressurizing device (36) onto the upper surface of the radiator (13) located around the irradiation spot (35) of the infrared laser beam. Laser welding equipment characterized by. The pressurizing device (36) includes a pressurizing head (38) having a gas injection port (37) and a gas supply mechanism (39) for supplying gas to the pressurizing head (38).
The pressurizing head (38) is composed of an air bearing formed in a hollow cylindrical shape having a hollow portion (49),
Both sheets (3.4) are irradiated with the infrared laser beam by the laser device (5) through the hollow portion (49) of the pressure applying head (38), and the end face of the pressure applying head (38) or the cylinder. The gas is jetted from the gas jet port (37) formed on the inner wall surface onto the upper surface of the radiator (13) located around the entire circumference of the irradiation spot (35). Laser welding equipment. An elevating mechanism (40) for moving the pressurizing head (38) in the vertical direction is provided,
The laser welding apparatus according to claim 2, wherein the lifting head (38) is configured to be vertically movable relative to the laser device (5) and the sheet pressing body (8) by the lifting mechanism (40). .. The upper side with respect to the interface of the thermoplastic resin sheets (3, 4) placed in a stacked state between the lower sheet table (7) and the upper sheet pressing body (8). A laser welding method in which both sheets (3, 4) are integrated by irradiating an infrared laser beam from the sheet to form a welded portion,
By injecting a gas onto the upper surface of the radiator (13) of the sheet pressing body (8) located in the vicinity of the irradiation spot (35) of the infrared laser beam, the thermoplasticity in the vicinity of the irradiation spot (35) is increased. While locally pressing and adhering the heat radiator (13) to the resin sheet (3.4) locally, the thermoplastic resin at the interface between both sheets (3.4) is heated and melted, so that both sheets (3・4) is welded,
It is set so that the gas injection area from the pressurizing device (36) on the upper surface of the radiator (13) and the infrared laser beam irradiation area by the laser device (5) on the upper surface of the radiator (13) do not overlap. In addition, the pressurizing device (36) is configured to inject gas onto the upper surface of the radiator (13) located around the entire irradiation spot (35) of the infrared laser beam. Laser welding method .

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