JP2015226920A - Laser processing device and laser processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device that can prevent oxidization on a rear face side of a processed part by a simple configuration at a low cost in laser processing that causes weld penetration to the rear face of the processed part, and to provide a laser processing method.SOLUTION: The laser processing device 200 includes: a laser irradiation part 210 irradiating a front face side W1 of the processed part W of work-pieces 50, 55 with a laser beam L to provide a laser processing causing weld penetration M reaching the rear face W2 of the processed part; and laser-resistant members 231(331), 232(332), 233(333) placed while coming into close contact with the rear face side of the processed part of the work-pieces and transmitting or absorbing at least part of the laser beam passing through the processed part.

Description

  The present invention relates to a laser processing apparatus and a laser processing method.

  Conventionally, there is a laser processing apparatus as an apparatus for processing a workpiece using laser light. Since the laser processing apparatus can accurately apply high-density energy to a portion to be processed by using a laser beam having high directivity, the workpiece can be processed with high accuracy. On the other hand, when processing is performed using a laser processing apparatus, there is a feature that the high density energy is concentrated and applied to the processing part, so that the penetration generated in the processing part tends to be deep. In particular, when the workpiece part is thin, the generated penetration may reach the back surface of the workpiece part. As a workpiece having a thin processing site, for example, there is a separator disposed on both surfaces of a membrane electrode assembly in a fuel cell. The separator may be manufactured, for example, by joining an anode side separator and a cathode side separator each having a thin plate shape by welding using a laser processing apparatus. When the penetration reaches the back surface of the processed part of the workpiece, the back surface side of the processed part becomes high temperature, and the material on the back surface side of the processed part and the oxygen existing in the vicinity of the back surface side of the processed part are combined to easily cause oxidation. Therefore, in order to prevent oxidation on the back surface side of the processing site, a method is known in which laser processing is performed after blowing a shield gas to the back surface side of the processing site so that oxygen does not exist (for example, patents). Reference 1).

JP 2009-178736 A

  However, in the configuration of Patent Document 1, it is necessary to always blow the shield gas to the back surface of the processing site when performing laser processing. Therefore, in order to prevent oxidation of the processing site, in addition to energy necessary for laser processing, energy for blowing the shield gas is required, which increases running cost. Further, since the shield gas must reach the back surface of the processed part after supporting the processed part, there is a problem that the configuration of the jig for supporting the workpiece becomes complicated.

  The present invention has been made in order to solve the above-described problems, and in laser processing involving penetration reaching the back surface of the processing site, laser processing that can prevent oxidation of the back surface side of the processing site with a simple configuration at low cost. An object is to provide an apparatus and a laser processing method.

  The present invention that achieves the above object is a laser processing apparatus having a laser irradiation unit that performs laser processing with laser beam irradiation on the surface side of a processing portion of a workpiece to reach the back surface of the processing portion. The laser processing apparatus further includes a laser-resistant member that is installed in close contact with the back surface side of the processing part of the workpiece and transmits or absorbs at least part of the laser light that has passed through the processing part.

  Another aspect of the present invention is a laser processing method in which laser processing is performed in which a laser beam is irradiated to the surface side of a workpiece processing portion to reach the back surface of the processing portion. In the laser processing method, a laser-resistant member that transmits or absorbs at least part of the laser light is installed on the back side of the workpiece processing part.

  According to the laser processing apparatus and the laser processing method of the present invention, a laser-resistant member that transmits or absorbs at least part of the laser light that has passed through the processing part is closely attached to the back side of the processing part of the workpiece. The Thus, laser processing can be performed after oxygen is not present on the back surface side of the processing site by a simple method that does not require additional energy, in which the laser resistant member is placed in close contact with the back surface of the processing site. Further, since the laser resistant member transmits or absorbs at least part of the laser beam, the laser resistant member can be prevented from being processed and welded to the processing site by the laser beam that has passed through the processing site. Therefore, according to the laser processing apparatus and the laser processing method of the present invention, it is possible to prevent oxidation on the back surface side of the processing site at a low cost with a simple configuration in laser processing that involves penetration reaching the back surface of the processing site.

FIG. 1A is a perspective view showing a laser processing apparatus according to Embodiment 1 of the present invention, and FIG. 1B is an exploded perspective view showing a part excluding the laser irradiation section of the inspection apparatus. 2 (A) and 2 (B) are a perspective view and a side view showing a mounting table of the processing apparatus. FIG. 3A and FIG. 3B are a front view and a plan view showing a mounting table of the processing apparatus. 4A is a cross-sectional view taken along line 4A-4A in FIG. 3A, and FIG. 4B is a cross-sectional view taken along line 4B-4B in FIG. FIG. 5A and FIG. 5B are a perspective view and a plan view showing a laser resistant member of the processing apparatus. It is a disassembled perspective view for demonstrating the fuel cell containing the separator processed by the processing apparatus. It is sectional drawing for demonstrating the single cell shown by FIG. It is a top view for demonstrating the welding site | part of the separator shown by FIG. It is sectional drawing explaining the mode in the processing head at the time of laser processing with the processing apparatus. 10A and 10B show the mounting table, the laser resistant member, the guide member, and the separator 4A-4A shown in FIG. 3A when the separator is mounted on the mounting table of the processing apparatus. It is sectional drawing cut | disconnected in the position corresponding to a 4B-4B line. It is explanatory drawing explaining the mode of the process of the separator by the same processing apparatus, Comprising: It is an enlarged view corresponding to the part enclosed by the broken-line part A of FIG. 10 (A). It is a flowchart which shows the process of laser processing a separator. FIGS. 13A and 13B are cross-sectional views showing a mounting table of a laser processing apparatus according to a modification of the first embodiment, and are cross-sectional views corresponding to FIGS. 4A and 4B. It is. 14 (A) and 14 (B) are cross-sectional views when the separator is placed on the mounting table of the processing apparatus, and are cross-sectional views corresponding to FIGS. 10 (A) and 10 (B). is there. It is explanatory drawing explaining the mode of the process of the separator by the same processing apparatus, Comprising: It is an enlarged view corresponding to the part enclosed by the broken-line part B of FIG. FIGS. 16A and 16B are cross-sectional views when the separator is mounted on the mounting table of the laser processing apparatus according to the second embodiment. FIG. 10A and FIG. FIG. It is explanatory drawing explaining the mode of processing of the separator by the same processing apparatus, Comprising: It is an enlarged view corresponding to the part enclosed by the broken-line part C of FIG. It is explanatory drawing explaining the mode of the process of the separator by the laser processing apparatus which concerns on another modification, Comprising: It is an enlarged view corresponding to FIG.11 and FIG.17.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the following description does not limit the technical scope and terms used in the claims. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from actual ratios.

(Embodiment 1)
FIG. 1A is a perspective view showing a laser processing apparatus according to Embodiment 1 of the present invention, and FIG. 1B is an exploded perspective view showing a part excluding the laser irradiation section of the inspection apparatus. 2A and 2B are a perspective view and a side view showing the mounting table of the processing apparatus, and FIGS. 3A and 3B are a front view and a plan view showing the mounting table of the processing apparatus. FIG. 4A is a cross-sectional view taken along line 4A-4A in FIG. 3A, and FIG. 4B is a cross-sectional view taken along line 4B-4B in FIG. FIG. 5A and FIG. 5B are a perspective view and a plan view showing a laser resistant member of the processing apparatus.

  6 is an exploded perspective view for explaining a fuel cell including a separator processed by the processing apparatus, FIG. 7 is a cross-sectional view for explaining a single cell shown in FIG. 6, and FIG. 8 is shown in FIG. It is a top view for demonstrating the welding site | part of a separator.

  FIG. 9 is a cross-sectional view illustrating a state in the machining head when laser machining is performed by the machining apparatus. 10A and 10B show the mounting table, the laser resistant member, the guide member, and the separator 4A-4A shown in FIG. 3A when the separator is mounted on the mounting table of the processing apparatus. It is sectional drawing cut | disconnected in the position corresponding to a 4B-4B line. FIG. 11 is an explanatory view for explaining a state of processing of the separator by the processing apparatus, and is an enlarged view corresponding to a portion surrounded by a broken line portion A in FIG.

  FIG. 12 is a flowchart showing a process of laser processing the separator.

  The laser processing apparatus 200 according to the present embodiment includes a laser irradiation unit 210, a mounting table 220, a laser resistant unit 230, a guide unit 240, and a workpiece fixing jig 250 (see FIG. 11). As shown in FIG. 1, the laser irradiation unit 210 includes a laser oscillator 211, an optical fiber 212, a driving device 213, a control device 214, and a processing head 260.

  As shown in FIG. 12, the laser processing method according to this embodiment includes installation of a laser resistant member (step ST1), placement of a separator (step ST2), fixing of a separator (step ST3), and laser processing (step ST4). Have

  Below, the case where the laser processing apparatus and laser processing method concerning this embodiment are applied to welding of the separator which is a constituent article of a fuel cell is explained as an example.

(Fuel cell)
First, a fuel cell including a separator welded by a laser processing apparatus and a laser processing method according to the present embodiment as a constituent article will be described. The fuel cell 100 is composed of, for example, a polymer electrolyte fuel cell and is used as a power source. A polymer electrolyte fuel cell (PEFC) can be reduced in size, increased in density and output, and is preferably applied as a power source for driving a moving body such as a vehicle in which a mounting space is limited. Particularly preferred is an automobile application in which start-up and stop-up and output fluctuation frequently occur. In this case, it can be mounted under the seat in the center of the vehicle body, in the lower part of the rear trunk room, and in the engine room in front of the vehicle. From the viewpoint of widening the interior space and the trunk room, mounting under the seat is preferable.

  As shown in FIG. 6, the fuel cell 100 includes a stack part 110, a fastening plate 130, a reinforcing plate 135, a current collecting plate 140, a spacer 145, an end plate 150, and a bolt 155.

  The stack unit 110 is composed of a stacked body of single cells 120. The single cell 120 has a membrane electrode assembly and a separator, as will be described later.

  The fastening plates 130 are disposed on the bottom surface and the top surface of the stack portion 110, and the reinforcing plates 135 are disposed on both sides of the stack portion 110. The fastening plate 130 and the reinforcing plate 135 constitute a casing that surrounds the stack portion 110.

  The current collector plate 140 is formed of a gas-impermeable conductive member such as dense carbon or copper plate, and is provided with an output terminal for outputting an electromotive force generated in the stack portion 110. Are disposed at both ends (the front surface and the back surface of the stack portion 110).

  The spacer 145 is disposed outside the current collector plate 140 disposed on the back surface of the stack unit 110.

  The end plate 150 is formed of a material having rigidity, for example, a metal material such as steel, and is disposed outside the current collector plate 140 disposed in front of the stack part 110 and outside the spacer 145. The end plate 150 has a fuel gas inlet, a fuel gas outlet, an oxidant gas inlet, an oxidant gas outlet, a refrigerant inlet, and a refrigerant outlet for circulating fuel gas, oxidant gas, and refrigerant. . The fuel gas, the oxidant gas, and the refrigerant are hydrogen gas, oxygen gas, and cooling water.

  The bolt 155 fastens the end plate 150, the fastening plate 130, and the reinforcing plate 135 and applies the fastening force in the stacking direction of the single cells 120 to hold the stack portion 110 located inside in a pressed state. Used for. The number of bolts 155 and the position of the bolt holes can be changed as appropriate. The fastening mechanism is not limited to screwing, and other means can be applied.

  The single cell 120 includes a membrane electrode assembly 40 and separators 50 and 55. The membrane electrode assembly 40 includes a polymer electrolyte membrane 20, a catalyst layer 30 that functions as an electrode (anode), a catalyst layer 35 that functions as an electrode (cathode), and gas diffusion layers 10 and 15.

  The gas diffusion layer 10 is located between the separator 50 and the catalyst layer 30 and is used to disperse the fuel gas supplied to the anode side and supply it to the catalyst layer 30. The gas diffusion layer 15 is disposed between the separator 55 and the catalyst layer 35 and is used to disperse the oxidant gas supplied to the cathode side and supply it to the catalyst layer 35.

  The catalyst layer 30 is an anode catalyst layer that contains a catalyst component, a conductive catalyst carrier that supports the catalyst component, and a polymer electrolyte, and in which a hydrogen oxidation reaction proceeds. It is arranged on the side. The catalyst layer 35 includes a catalyst component, a conductive catalyst carrier that supports the catalyst component, and a polymer electrolyte, and is a cathode catalyst layer in which a reduction reaction of oxygen proceeds, and the other of the polymer electrolyte membrane 20 It is arranged on the side.

  The polymer electrolyte membrane 20 selectively permeates protons generated in the anode catalyst layer 30 to the cathode catalyst layer 35 and does not mix the fuel gas supplied to the anode side and the oxidant gas supplied to the cathode side. Function as a partition wall.

  The separators 50 and 55 have a function of electrically connecting the single cells in series and a function of a partition that blocks the fuel gas, the oxidant gas, and the refrigerant from each other, and have substantially the same shape as the membrane electrode assembly 40. Yes, it is formed by pressing a thin plate-like stainless steel plate. The separator 50 is welded to the separator 55 of another adjacent single cell 120, and the separator 55 is welded to the separator 50 of another adjacent single cell 120.

  The stainless steel plate is preferable in that it can be easily subjected to complicated machining and has good electrical conductivity, and can be coated with corrosion resistance as necessary. Separator 50,55 is not limited to the form which comprises a stainless steel rod, It is also possible to apply metal materials other than a stainless steel rod, for example, an aluminum plate and a clad material.

  The separator 50 is an anode separator that is disposed on the anode side of the membrane electrode assembly 40, is disposed to face the catalyst layer 30, and includes an active area portion 52 and a manifold portion 65. The active area portion 52 is formed with a concavo-convex portion constituting a flow path 53 located between the membrane electrode assembly 40 and the separator 50. The flow path 53 is used for supplying fuel gas to the catalyst layer 35. The manifold portion 65 is provided with manifold holes 66, 67, 68 for fuel gas passage, oxidant gas passage, and refrigerant passage. Reference numeral 59 denotes a refrigerant flow path.

  The separator 55 is a cathode separator disposed on the cathode side of the membrane electrode assembly 40, is disposed to face the catalyst layer 35, and has an active area portion 57 and a manifold portion 75. The active area portion 57 is formed with a concavo-convex portion constituting a flow path 58 located between the membrane electrode assembly 40 and the separator 55. The manifold portion 75 is provided with manifold holes 76, 77, 78 for fuel gas passage, oxidant gas passage, and refrigerant passage. The flow path 58 is used to supply the oxidant gas to the catalyst layer 35.

  The active area portions 52 and 57 are regions in contact with regions contributing to power generation of the membrane electrode assembly 40. Reference numerals 80 and 90 indicate the welded portions of the active area portions 52 and 57 and the welded portions of the outer circumferences 60 and 70 (see FIG. 8).

  Next, materials for the polymer electrolyte membrane 20 and the catalyst layers 30 and 35 will be described.

  The polymer electrolyte membrane 20 is a porous polymer electrolyte membrane composed of a perfluorocarbon sulfonic acid polymer, a porous resin membrane having a sulfonic acid group, and a porous material impregnated with an electrolyte component such as phosphoric acid or ionic liquid. A shaped film can be applied. Examples of the perfluorocarbon sulfonic acid polymer include Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei Co., Ltd.), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), and Gore select series (registered trademark). , Nippon Gore Co., Ltd.). The porous film is made of, for example, polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVDF).

  The thickness of the polymer electrolyte membrane 20 is not particularly limited, but is preferably 5 μm to 300 μm, more preferably 10 to 200 μm from the viewpoint of strength, durability, and output characteristics.

  The catalyst component used for the anode catalyst layer 30 is not particularly limited as long as it has a catalytic action for the oxidation reaction of hydrogen. The catalyst component used for the cathode catalyst layer 35 is not particularly limited as long as it has a catalytic action in the oxygen reduction reaction.

  Specific catalyst components include platinum, ruthenium, iridium, rhodium, palladium, osmium, tungsten, lead, iron, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, aluminum and other alloys, and alloys thereof. Selected. In order to improve catalytic activity, poisoning resistance to carbon monoxide, heat resistance, etc., those containing at least platinum are preferable. The catalyst components applied to the cathode catalyst layer and the anode catalyst layer need not be the same, and can be selected as appropriate. It is also possible to apply a catalyst containing no noble metal.

  The conductive carrier of the catalyst used for the catalyst layers 30 and 35 is not particularly limited as long as it has a specific surface area for supporting the catalyst component in a desired dispersed state and sufficient electronic conductivity as a current collector. The main component is preferably carbon particles. The carbon particles are composed of, for example, carbon black, activated carbon, coke, natural graphite, and artificial graphite.

  The polymer electrolyte used for the catalyst layers 30 and 35 is not particularly limited as long as it is a material having at least high proton conductivity. For example, a fluorine-based electrolyte containing a fluorine atom in all or part of the polymer skeleton or a polymer A hydrocarbon-based electrolyte that does not contain a fluorine atom in the skeleton is applicable. The polymer electrolyte used for the catalyst layers 30 and 35 may be the same as or different from the polymer electrolyte used for the polymer electrolyte membrane 20, but the catalyst layers 30 and 35 adhere to the polymer electrolyte membrane 20. From the viewpoint of improving the properties, it is preferable that they are the same.

(Laser processing equipment)
Next, the laser processing apparatus 200 according to the present embodiment will be described.

  The laser processing apparatus 200 includes a laser irradiation unit 210, a mounting table 220, a laser resistant unit 230, a guide unit 240, and a workpiece fixing jig 250 (see FIG. 11).

  As shown in FIG. 1, the laser irradiation unit 210 includes a laser oscillator 211, an optical fiber 212, a driving device 213, a control device 214, and a processing head 260. As shown in FIG. 11, the laser irradiation unit 210 irradiates the front surface W1 of the processing site W of the separators 50 and 55 with laser light L and performs laser processing with the penetration M reaching the back surface W2 of the processing site W. .

  The laser oscillator 211 is, for example, a YAG laser oscillator and includes an optical system, a power supply, a control system, a cooling gas circulation system, and the like, and the generated laser is supplied to the processing head 260 using the optical fiber 212. Is done. In the control system, for example, an output adjustment unit that adjusts the oscillation output by changing the electric power is arranged. As the laser oscillator 211, another solid-state laser such as a semiconductor laser or a gas laser such as a carbon dioxide laser can be applied as appropriate.

  As shown in FIG. 1, the driving device 213 includes a plurality of linear guides 215 and 216, and is used to move and position the machining head 260. The driving device 213 can also be configured by a multi-axis (multi-joint type) robot.

  The control device 214 includes a control circuit including, for example, a microprocessor and is used to control the laser oscillator 211, the driving device 213, and the processing head 260.

  As shown in FIG. 9, the processing head 260 is a galvano head that can be continuously welded by scanning a laser, and includes a collimator 261, a laser diameter adjustment unit 262, a reflection mirror 263, a galvano scanner 264, and a processing lens 265. Have.

  The collimator 261 is used to convert a laser introduced from the optical fiber 212 into parallel light. The laser diameter adjusting unit 262 is an optical system for adjusting the laser diameter. For example, when the laser diameter is adjusted to decrease at this position, the laser diameter at the welded portion increases. The reflection mirror 263 is a folding mirror that is used to reflect the laser beam that has passed through the laser diameter adjusting unit 262 and project the reflected laser beam onto the galvano scanner 264.

  The galvano scanner 264 is, for example, a two-axis type, has two mirrors and a motor that drives the mirrors, and is configured to be able to scan the laser in a two-dimensional direction by changing the reflection direction of the laser.

  The processing lens 265 includes, for example, an fθ lens, and is used to collect the laser reflected by the galvano scanner 264. Reference numeral 266 indicates a protective glass for protecting the processed lens 265.

  As shown in FIGS. 2 to 4, the mounting table 220 includes a manifold unit fixing jig 221 and grooves 222, 223, and 224.

  The manifold portion fixing jig 221 includes a locate pin 225 and a clamp 226 as shown in FIG. The locating pin 225 is movable in three directions X, YL, and YR, and is inserted into the manifold holes 68 and 78 for passage of refrigerant in the manifold portions 65 and 75 of the separators 50 and 55, and the manifold holes 68 and 78 are used as a reference. Used for positioning. The direction X is a direction away from the active area portions 52 and 57. The direction YL is a direction orthogonal to the direction X. The direction YR is a direction orthogonal to the direction X and opposite to the direction YL. The clamp 226 has a plurality of clamp pieces configured to be separable from each other, and is inserted into the manifold holes 66, 76 and 67, 77 for passing the fuel gas and the oxidant gas to fix the manifold portions 65, 75. Used to do.

  The grooves 222, 223, and 224 are grooves provided on the mounting table 220 in order to install laser resistant members 231, 232, and 233 of the laser resistant part 230 described later, respectively. The grooves 222, 223, and 224 are set at positions corresponding to the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55, respectively. Specifically, the grooves 222, 223, and 224 are positioned immediately below the welded portions 80, 90, and 95 (corresponding to the processed portion W), respectively, when the separators 50 and 55 are mounted on the mounting table 220. (See FIG. 11).

  As shown in FIG. 5, the laser resistant unit 230 includes laser resistant members 231, 232, and 233. The laser resistant members 231, 232, and 233 are installed in the grooves 222, 223, and 224 of the mounting table 220, respectively (see FIGS. 4 and 10).

  The dimensions of the laser resistant members 231, 232, and 233 are such that the laser resistant members 231, 232, The dimension at which 233 is in close contact is set. Specifically, when the vicinity of the welded portions 80, 90, 95 of the separators 50, 55 is pressed by a workpiece fixing jig 250 described later, the backside W2 of the welded portions 80, 90, 95 of the separators 50, 55 is applied. It sets so that it may contact | adhere (refer FIG. 11). Thereby, when performing laser processing, it will be in the state where oxygen does not exist in the vicinity of back side W2 of welding parts 80, 90, and 95 (equivalent to processing part W) of separators 50 and 55. That is, laser processing can be performed in a state where oxygen is not present in the vicinity of the back surface W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. As the dimensions of the laser resistant members 231, 232, 233, the heights h1, h2, h3 (see FIG. 5) of the laser resistant members 231, 232, 233 are the heights H1, H2, H2 of the grooves 222, 223, 224, respectively. It can be set to be equal to or higher than H3 (see FIG. 4).

  Further, the laser resistant members 231, 232, and 233 according to the present embodiment are made of a material that transmits at least part of the laser light L. Specifically, the laser resistant members 231, 232 and 233 are made of a material transparent to the laser beam L. More specifically, the laser resistant members 231, 232, 233 are made of a material that transmits 90% or more of the laser light L incident on the laser resistant members 231, 232, 233. Accordingly, the laser resistant members 231, 232, and 233 transmit at least a part of the laser light L that has passed through the separators 50 and 55 among the laser light L scanned from the processing head 260. That is, the laser resistant members 231, 232, and 233 are prevented from being processed by the laser scanned from the processing head 260. Therefore, welding of the laser resistant members 231, 232, 233 to the separators 50, 55 is prevented. Examples of materials that transmit 90% or more of the laser light L incident on the laser resistant members 231, 232, and 233 include synthetic quartz, acrylic, and polycarbonate, but are not particularly limited.

  As shown in FIG. 1, the guide part 240 includes guide members 241 and 242. The guide members 241 and 242 are used to assist the fixing of the outer peripheries 60 and 70 of the separators 50 and 55 by abutting and pressing the outer peripheries 60 and 70 of the separators 50 and 55 (FIG. 1B). And FIG. 10). Thereby, the separators 50 and 55 mounted on the mounting table 220 are fixed at predetermined positions. Specifically, the positions of the separators 50, 55 are fixed so that the laser resistant members 231, 232, 233 are positioned on the back side W2 of the welded parts 80, 90, 95 (corresponding to the processed part W) of the separators 50, 50. Is done.

  As shown in FIG. 11, when the workpiece fixing jig 250 welds the separators 50 and 55 by scanning the laser beam L from the processing head 260, the welding parts 80, 90, and 95 (processing parts) of the separators 50 and 55 are processed. (Corresponding to W) is used to press toward the mounting table 220. By pressing the vicinity of the welded portions 80, 90, 95 (corresponding to the processed portion W) of the separators 50, 55 with the work fixing jig 250, the laser resistant members 231, 232, 233 are formed on the back side W2 of the processed portion W. Each is securely attached (see FIG. 11).

(Laser processing method)
Next, the laser processing method according to this embodiment will be described. In brief, the laser processing method according to the present embodiment, as shown in FIG. 12, installation of a laser resistant member (step ST1), placement of a separator (step ST2), fixing of a separator (step ST3) and laser processing (step ST1). Step ST4).

  In the installation of the laser resistant member, the laser resistant members 231, 232 and 233 are installed in the grooves 222, 223 and 224 of the mounting table 220, respectively.

  Next, in placing the separator, the separators 50 and 55 to be subjected to laser processing are placed on the placing table 220. Specifically, the locating pin 225 of the manifold portion fixing jig 221 is placed so as to be inserted into the coolant passage manifold holes 68 and 78 of the manifold portions 65 and 75 of the separators 50 and 55. At this time, the clamp 226 of the manifold portion fixing jig 221 is inserted into the manifold holes 66, 76 and 67, 77 for passage of fuel gas and oxidant gas of the manifold portions 65, 75 of the separators 50, 55. Next, the separator pins 225 are appropriately moved in the directions X, YL, and YR to position the separators 50 and 55 with reference to the manifold holes 68 and 78. At this time, positioning of the separators 50 and 55 is assisted by bringing the guide members 241 and 242 into contact with and pressing the outer peripheries 60 and 70 of the separators 50 and 55. Next, the manifold portions 65 and 75 are fixed by appropriately moving the clamp pieces of the clamp 226.

  Next, in the fixing of the separator, the vicinity of the welded portions 80, 90, 95 (corresponding to the processing portion W) of the separators 50, 55 is pressed and fixed toward the mounting table 220 by the work fixing jig 250. Thereby, the laser resistant members 231, 232, and 233 are securely adhered to the back side W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. That is, oxygen is not present in the vicinity of the back side W2 of the welded portions 80, 90, 95 of the separators 50, 55.

  Next, in the laser processing, the processing head 260 of the laser irradiation unit 210 is moved and positioned at predetermined positions for welding the outer peripheries 60 and 70 of the separators 50 and 55 and the manifold portions 65 and 75. The laser from the laser oscillator 211 passes through the optical fiber 212 and is introduced into the processing head 260. The laser passes through the collimator 261, the laser diameter adjustment unit 262, the reflection mirror 263, the galvano scanner 264, the processing lens 265, and the protective glass 266, and is emitted from the processing head 260 (see FIG. 9). Then, the laser beam L emitted from the machining head 260 is applied to the welding parts 80, 90, and 95 (corresponding to the machining part W) of the separators 50 and 55 to perform welding. At this time, since the separators 50 and 55 are made of thin plate-like members, there are places where the melt M reaches the back side W2 at the welded portions 80, 90, and 95 of the separators 50 and 55 (see FIG. 11). However, the laser resistant members 231, 232, and 233 are securely in close contact with the back side W 2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. That is, oxygen is not present in the vicinity of the back surface side W2 of the welded portions 80, 90, 95 of the separators 50, 55. Therefore, the penetration M reaches the back side W2 of the welded parts 80, 90, and 95, so that the back side W2 is heated and the back side W2 is prevented from being oxidized. Further, the laser resistant members 231, 232, and 233 transmit at least a part of the laser light L that has passed through the separators 50 and 55 among the laser light L scanned from the processing head 260. That is, the laser resistant members 231, 232, and 233 are prevented from being processed by the laser light L scanned from the processing head 260. Therefore, welding of the laser resistant members 231, 232, 233 to the separators 50, 55 is prevented.

  As described above, according to the laser processing apparatus 200 and the laser processing method according to the present embodiment, the back surface side W2 of the welded portions 80, 90, and 95 (corresponding to the processing portion W) of the separators 50 and 55 (corresponding to the workpiece). Are installed in close contact with laser resistant members 231, 232, 233 that transmit at least part of the laser beam L that has passed through the processing site W. Thus, oxygen is not present on the back side W2 of the processing site W in a simple and non-additional manner in which the laser resistant members 231, 232, 233 are placed in close contact with the back side W2 of the processing site W. Laser processing can be performed after making the state. Further, since the laser resistant members 231, 232, 233 transmit at least part of the laser beam L, the laser resistant members 231, 232, 233 are processed by the laser beam L that has passed through the processing site W to form the processing site W. It can prevent welding. Therefore, according to the laser processing apparatus 200 and the laser processing method according to the present embodiment, in the laser processing with the penetration M reaching the back surface side W2 of the processing site W, the back surface side W2 of the processing site W with a simple configuration at low cost. Can prevent oxidation.

  Further, the laser resistant members 231, 232 and 233 are made of a material transparent to the laser beam L. As a result, the laser light L that has passed through the processing site W is transmitted without processing the laser resistant members 231, 232, and 233. Therefore, it is possible to reliably prevent the laser resistant members 231, 232, 233 from being processed and welded to the processing site W. Therefore, in the laser processing with the penetration M reaching the back surface side W2 of the processing site W, the oxidation of the back surface side W2 of the processing site W can be prevented with higher quality.

  The laser resistant members 231, 232, and 233 are made of a material that transmits 90% or more of the laser light L incident on the laser resistant members 231, 232, and 233. Thereby, it is possible to further reliably prevent the laser resistant members 231, 232 and 233 from being processed and welded to the processing site W by the laser light L that has passed through the processing site W. Therefore, in the laser processing with the penetration M reaching the back surface side W2 of the processing site W, the oxidation of the back surface W2 of the processing site W can be prevented with higher quality.

  Further, the laser processing apparatus 200 and the processing method according to the present embodiment can be applied to the base material for the separators 50 and 55 used in the fuel cell 100. Therefore, for the separators 50 and 55 used in the fuel cell 100, laser processing with penetration M that reaches the back side W2 of the processing part W is prevented at low cost and with high quality, and oxidation of the back side W2 of the processing part W is prevented. Can be suitably used for processing of the substrate.

(Modification)
In the mounting table 220 of the laser processing apparatus 200 according to the first embodiment, the laser resistant members 231, 232, 233 are installed in close contact with the back side W2 of the processing site W, and at least one of the laser beams L that have passed through the processing site W. It is possible to change as long as it passes through the part.

  For example, the grooves 222, 223, and 224 of the mounting table 220 may be provided with spaces S1, S2, and S3 that allow the laser light L that has passed through the laser resistant members 231, 232, and 233 to escape. As a result, the laser light L can easily pass through the laser resistant members 231, 232, and 233. Therefore, the laser resistant members 231, 232 and 233 can be more reliably prevented from being processed by the laser light L.

  FIGS. 13A and 13B are cross-sectional views showing a mounting table of a laser processing apparatus according to this modification, and are cross-sectional views corresponding to FIGS. 4A and 4B. 14 (A) and 14 (B) are cross-sectional views when the separator is mounted on the mounting table of the processing apparatus, and are cross-sectional views corresponding to FIGS. 10 (A) and 10 (B). is there. FIG. 15 is an explanatory view for explaining a state of processing of the separator by the processing apparatus, and is an enlarged view corresponding to a portion surrounded by a broken line portion B in FIG.

  As shown in FIGS. 13 to 15, protrusions 227, 228, and 229 are formed along the side walls of the grooves 222, 223, and 224 as a method of providing spaces S 1, S 2, and S 3 in the grooves 222, 223, and 224 for releasing the laser light L. Although the method of providing can be illustrated, it is not specifically limited. The protrusions 227, 228, and 229 have heights H4, H5, and H6 (see FIG. 13) from the protrusions 227, 228, and 229 to the openings of the grooves 222, 223, and 224 (see FIG. 13). The height h1, h2, h3 (see FIG. 5) or less can be provided. As a result, when the vicinity of the welded portions 80, 90, 95 (corresponding to the processed portion W) of the separators 50, 55 is pressed by the work fixing jig 250, laser resistance is applied to the back side W2 of the welded portions 80, 90, 95. The members 231, 232, and 233 are brought into close contact with each other (see FIG. 15).

  According to the laser processing apparatus 200 and the laser processing method according to this modification, the spaces S1, S2, and the grooves 222, 223, and 224 of the mounting table 220 allow the laser light L transmitted through the laser resistant members 231, 232, and 233 to escape. S3. As a result, the laser light L can easily pass through the laser resistant members 231, 232, and 233. Therefore, the laser resistant members 231, 232 and 233 can be more reliably prevented from being processed by the laser light L. Therefore, in the laser processing with the penetration M reaching the back surface side W2 of the processing site W, the oxidation of the back surface W2 of the processing site W can be prevented with higher quality.

(Embodiment 2)
The laser processing apparatus 300 according to the second embodiment is different from the laser processing apparatus 200 according to the first embodiment in the following points. That is, the laser resistant members 231, 232, and 233 of the laser resistant portion 230 of the laser processing apparatus 200 according to the first embodiment transmit at least part of the laser light L. On the other hand, the laser processing apparatus 300 according to the second embodiment is different from the laser processing apparatus 200 according to the first embodiment in that the laser resistant members 331, 332, and 333 of the laser resistant section 330 absorb at least part of the laser light L. .

  A configuration related to the above-described difference will be described below. The same components as those of the laser processing apparatus 200 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIGS. 16A and 16B are cross-sectional views when the separator is mounted on the mounting table of the laser processing apparatus according to the second embodiment. FIG. 10A and FIG. FIG. FIG. 17 is an explanatory view for explaining a state of processing of the separator by the processing apparatus, and is an enlarged view corresponding to a portion surrounded by a broken line portion C in FIG.

  The laser processing apparatus 300 according to the present embodiment includes a laser irradiation unit 210, a mounting table 220, a laser resistant unit 330, a guide unit 240, and a workpiece fixing jig 250 (see FIG. 17).

  The laser resistant part 330 includes laser resistant members 331, 332, and 333 shown in FIG. The laser resistant members 331, 332, 333 are installed in the grooves 222, 223, 224 (see FIG. 4) of the mounting table 220, respectively.

  The laser resistant members 331, 332, and 333 according to the present embodiment are made of a material that absorbs at least part of the laser light L. Specifically, the laser resistant members 331, 332, and 333 of the present embodiment are made of a liquid that absorbs at least part of the laser light L. Thereby, the laser resistant members 331, 332, 333 absorb at least a part of the laser light L that has passed through the separators 50, 55 among the laser light L scanned from the machining head 260, as shown in FIG. . That is, the laser resistant members 331, 332, and 333 are prevented from being processed by the laser scanned from the processing head 260. Therefore, welding of the laser resistant members 331, 332, 333 to the separators 50, 55 is prevented. Further, since the laser resistant members 331, 332, and 333 are made of liquid, it is not necessary to mold the laser resistant member. Although water etc. can be illustrated as a liquid which absorbs at least one part of the laser beam L which comprises the laser resistant members 331,332,333, It is not specifically limited.

  The amount of the laser resistant members 331, 332, 333 installed in the grooves 222, 223, 224 of the mounting table 220 is set as follows. That is, when laser processing is performed, the amount is set such that the laser resistant members 331, 332, and 333 are in close contact with the back side W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. Specifically, when the vicinity of the welded portions 80, 90, 95 of the separators 50, 55 is pressed by the work fixing jig 250, the welded portions 80, 90, 95 of the separators 50, 55 are in close contact with the back side W2. (See FIG. 17). More specifically, the heights of the liquids constituting the laser resistant members 331, 332, 333 installed in the grooves 222, 223, 224 are the heights H1, H2, H3 ( (See FIG. 4). Thereby, when performing laser processing, it will be in the state where oxygen does not exist in the vicinity of back side W2 of welding parts 80, 90, and 95 (equivalent to processing part W) of separators 50 and 55. That is, laser processing can be performed in a state where oxygen is not present in the vicinity of the back surface W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55.

(Laser processing method)
Next, the laser processing method according to this embodiment will be described. The laser processing method according to the second embodiment is different from the laser processing method according to the first embodiment in the following points. That is, in the installation of the laser resistant member (step ST1) of the laser processing method according to the first embodiment, the laser resistant members 231, 232, 233 that transmit at least part of the laser light L are installed. On the other hand, the laser processing method according to the second embodiment is different from the laser processing method according to the first embodiment in that laser resistant members 331, 332, and 333 that absorb at least part of the laser light L are installed.

  A configuration related to the above-described difference will be described below.

  The general flow of laser processing according to this embodiment is the same as that shown in FIG. In brief, the laser processing method according to the present embodiment includes installation of a laser resistant member (step ST1), placement of a separator (step ST2), fixing of the separator (step ST3), and laser processing (step ST4). Since the placement of the separator (step ST2), the fixing of the separator (step ST3), and the laser processing (step ST4) are the same as those in the first embodiment, the description thereof is omitted.

  In the installation of the laser resistant member, the laser resistant members 331, 332, and 333 that absorb at least part of the laser light L are installed in the grooves 222, 223, and 224 of the mounting table 220, respectively. Specifically, a liquid that absorbs at least part of the laser light L constituting the laser resistant members 331, 332, 333 is poured into the grooves 222, 223, 224 of the mounting table 220. At this time, the amount of liquid that absorbs at least a part of the laser light L constituting the laser resistant members 331, 332, and 333 poured into the grooves 222, 223, and 224 of the mounting table 220 is set as follows. That is, when laser processing is performed, the amount is set such that the laser resistant members 331, 332, and 333 are in close contact with the back side W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. Specifically, when the vicinity of the welded portions 80, 90, 95 of the separators 50, 55 is pressed by the work fixing jig 250, the welded portions 80, 90, 95 of the separators 50, 55 are in close contact with the back side W2. (See FIG. 17). More specifically, the heights of the liquids constituting the laser resistant members 331, 332, 333 installed in the grooves 222, 223, 224 are the heights H1, H2, H3 ( (See FIG. 4). Thus, when the separators 50 and 55 are placed on the placing table 220, the laser resistant members 331, 332, and 333 are placed on the back side W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. Is closely attached. Therefore, when laser processing is performed, oxygen is not present in the vicinity of the back surface side W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. That is, laser processing can be performed in a state where oxygen is not present in the vicinity of the back surface W2 of the welded portions 80, 90, and 95 (corresponding to the processed portion W) of the separators 50 and 55. Further, the laser resistant members 331, 332, 333 absorb at least part of the laser light L that has passed through the separators 50, 55 among the laser light L scanned from the processing head 260 (see FIG. 17). That is, the laser resistant members 331, 332, and 333 are prevented from being processed by the laser scanned from the processing head 260. Therefore, welding of the laser resistant members 331, 332, 333 to the separators 50, 55 is prevented. Further, since the laser resistant members 331, 332, and 333 are made of liquid, it is not necessary to mold the laser resistant member.

  According to the laser processing apparatus 300 and the laser processing method according to the present embodiment, at least a part of the laser light L that has passed through the processing site W is present on the back surface side W2 of the processing site W of the separators 50 and 55 (corresponding to workpieces). Laser-resistant members 331, 332, 333 that absorb light are installed in close contact with each other. Thus, the laser resistant members 331, 332, and 333 are placed in close contact with the back surface of the processing site W, and the oxygen does not exist on the back surface side W2 of the processing site W by a method that does not require additional energy. And laser processing can be performed. Further, since the laser resistant members 331, 332, and 333 absorb at least a part of the laser beam L, the laser resistant members 331, 332, and 333 are processed by the laser beam L that has passed through the processing site W, so that the processing site W is processed. It can prevent welding. Therefore, according to the laser processing apparatus 300 and the laser processing method according to the present embodiment, in the laser processing with the penetration M reaching the back surface side W2 of the processing site W, the back surface side W2 of the processing site W at a low cost with a simple configuration. Can prevent oxidation.

  Further, the laser resistant members 331, 332, and 333 are made of a liquid that absorbs at least part of the laser light L that has passed through the processing site W. As a result, the laser light L that has passed through the processing site W is absorbed without processing the laser resistant members 331, 332, and 333. Therefore, it is possible to reliably prevent the laser resistant members 331, 332, 333 from being processed and welded to the processing site W. Further, since the laser resistant members 331, 332, and 333 are made of liquid, it is not necessary to mold the laser resistant members 331, 332, and 333. Therefore, in laser processing with the penetration M reaching the back surface side W2 of the processing site W, the back surface side W2 of the processing site W can be prevented from being oxidized at a lower cost and with higher quality.

(Other modifications)
The laser resistant part 230 according to the first embodiment and the laser resistant part 330 according to the second embodiment are installed in close contact with the back side W2 of the processing site W, and transmit at least part of the laser light L that has passed through the processing site W. Or as long as it absorbs, it is possible to change.

  For example, the laser resistant members 231 (331), 232 (332), and 233 (333) of the laser resistant portion 230 (330) are elastic members that transmit or absorb at least part of the laser light L that has passed through the processing site W. It may be configured. At this time, the heights h1, h2, and h3 (see FIG. 5A) of the laser resistant members 231 (331), 232 (332), and 233 (333) are set to the heights H1, H2 of the grooves 222, 223, and 224, respectively. , H3 (see FIG. 4). Alternatively, the heights h1, h2, and h3 are heights H4, H5, and H6 from the protrusions 227, 228, and 229 described in the modification of the first embodiment to the openings of the grooves 222, 223, and 224 (see FIG. 13). Can be set higher. Thus, when the separators 50 and 55 placed on the placing table 220 are pressed by the work fixing jig 250, the laser resistant members 231 (331), 232 (332), and 233 (333) are separated from the separators 50 and 55, respectively. To be compressed. At this time, the separators 50 and 55 are separated from the laser resistant members 231 (331), 232 (332), and 233 (333) by the restoring force of the laser resistant members 231 (331), 232 (332), and 233 (333). Receives a stronger pressing force. Therefore, the separators 50 and 55 are more strongly pressed between the workpiece fixing jig 250 and the laser resistant members 231, 232 and 233 (see FIG. 18). That is, the separators 50 and 55 can be welded by the laser beam L in a state where the separators 50 and 55 are more firmly adhered to each other at the welding parts 80, 90, and 95. Therefore, according to the laser processing apparatus and the laser processing method according to this modification, the separators 50 and 55 can be more reliably joined.

  In addition, this invention is not limited only to embodiment mentioned above, its modification, and a modification, A various change is possible in a claim. For example, in the above-described embodiment and its modifications and modifications, lap welding has been described as an example of laser welding, but the laser processing apparatus and the laser processing method according to the present invention are in other forms such as butt welding. Applicable to welding. In the above-described embodiment and its modifications and modifications, laser welding has been described as an example of laser processing. However, the laser processing apparatus and laser processing method according to the present invention can be applied to various types of processing using a laser. It is. For example, the laser processing apparatus and the laser processing method according to the present invention can be applied to heat treatment of a workpiece surface using a laser.

10, 15 Gas diffusion layer,
20 polymer electrolyte membrane,
30, 35 catalyst layer,
40 membrane electrode assembly,
50,55 separator,
52,57 Active area part,
53, 58, 59 flow path,
60,70 outer circumference,
65,75 Manifold part,
66, 67, 68, 76, 77, 78 Manifold hole,
80, 90, 95 welded parts,
100 fuel cells,
110 Stack part,
120 single cells,
130 fastening plate,
135 reinforcing plate,
140 current collector,
145 spacer,
150 end plate,
155 volts,
200,300 Laser processing equipment,
210 Laser irradiation unit,
211 laser oscillator,
212 optical fiber,
213 drive,
214 control device,
215, 216 linear guide,
220 mounting table,
221 Manifold fixing jig,
222, 223, 224 grooves,
225 Locate pin,
226 clamp,
227, 228, 229 protrusions,
230, 330 Laser resistant part,
231,232,233,331,332,333 laser resistant member,
240 guide part,
241,242 guide members,
250 workpiece fixing jig,
260 processing head,
261 collimator,
262 laser diameter adjustment unit,
263 reflection mirror,
H.264 galvano scanner,
265 processing lens,
266 protective glass,
X, YL, YR direction,
L laser light,
M melting,
H1, H2, H3, H4, H5, H6, h1, h2, h3 height,
S1, S2, S3 space,
W processing part,
W1 Surface side of the processing site,
W2 Back side of the processed part.

Claims (6)

A laser irradiation unit that performs laser processing with a penetration that reaches the back surface of the processing part by irradiating the front side of the processing part of the workpiece;
A laser processing apparatus, comprising: a laser-resistant member that is installed in close contact with the back surface side of the processing portion of the workpiece and transmits or absorbs at least part of the laser light that has passed through the processing portion.   The laser processing apparatus according to claim 1, wherein the laser resistant member is made of a material transparent to the laser light.   The laser processing apparatus according to claim 1, wherein the laser resistant member transmits 90% or more of the laser light incident on the laser resistant member.   The laser processing apparatus according to claim 1, wherein the laser resistant member is made of a liquid.   The laser processing apparatus according to claim 1, wherein the workpiece is a separator base material used in a fuel cell. A laser-resistant member that transmits or absorbs at least part of the laser light is installed on the back side of the workpiece processing part,
A laser processing method in which laser processing is performed in which the laser beam is irradiated to the front surface side of the processing site of the workpiece to reach the back surface of the processing site.