Laser processing apparatus and laser processing method

Abstract

The present invention provides a laser processing apparatus and a laser processing method that can form openings in a workpiece with high precision. [Solution] The laser processing apparatus 1 comprises a mounting table 10 on which a workpiece 100 is placed, an irradiation means 20 for irradiating the workpiece 100 placed on the mounting table 10 with laser light, and a control unit 50 for controlling the irradiation of the laser light by the irradiation means 20. The workpiece 100 is placed on the mounting table 10 so that the laser light is incident at an oblique angle to one surface 101 of the workpiece 100. The control unit 50 irradiates the workpiece 100 while moving the laser light in a direction intersecting the incident direction, processing it in predetermined thickness increments, and controls the irradiation means 20 to form an opening of a desired shape that penetrates from one surface 101 to the other surface 102 of the workpiece 100.

Description

Technical Field

[0001] The present disclosure relates to a laser processing apparatus and a laser processing method.

Background Art

[0002] Conventionally, processing apparatuses that irradiate an object with laser light to process the object have been reported. For example, in Patent Document 1, the position and shape of a specimen are measured using two types of light sources and irradiation systems. Further, in combination with a laser processing optical system, the measured information is fed back to perform high-precision processing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There are cases where it is required to form an opening in a workpiece. When forming an opening in a workpiece, when laser light is incident on one surface (the processing surface) of the workpiece in a method perpendicular (surface normal) to the surface, it is difficult to cope with variations in the plate thickness of the workpiece. Specifically, when the plate thickness of the workpiece is thicker than expected, the processing of the workpiece may not be sufficient and penetration may not be achieved, or when the plate thickness of the workpiece is thinner than expected, the workpiece may be over-processed and an opening with a width larger than desired may be formed. Thus, when laser light is incident in a surface-normal manner, there is a problem that it is difficult to control the shape of the opening finally formed. In particular, it has been difficult to apply to structures such as turbine blades where the inner wall is damaged by the penetrating laser light.

[0005] Furthermore, while Patent Document 1 measures the processed shape and position and reflects them in the processing conditions, there is a possibility that the processing quality may decrease at working distances where the processing speed is high, and in some cases the desired quality of processing may not be achieved.

[0006] This disclosure has been made in view of these circumstances and aims to provide a laser processing apparatus and a laser processing method that can form an opening in a workpiece with high precision. [Means for solving the problem]

[0007] To solve the above problems, the laser processing apparatus of the present disclosure comprises a mounting table on which a workpiece is placed, an irradiation means for irradiating the workpiece placed on the mounting table with laser light, and a control unit for controlling the irradiation of the laser light by the irradiation means, wherein the workpiece is placed on the mounting table such that the laser light is incident at an oblique angle to one surface of the workpiece, and the control unit controls the irradiation means to process the workpiece in predetermined thickness increments by irradiating the laser light while moving it in a direction intersecting the incident direction, thereby forming an opening of a desired shape that penetrates from one surface to the other of the workpiece.

[0008] Furthermore, the laser processing method of this disclosure includes a placement step of placing the workpiece on a mounting table such that laser light from an irradiation means is incident obliquely on one surface of the workpiece, and a processing step of irradiating the workpiece while moving the laser light in a direction intersecting the incident direction to process it in predetermined thickness increments, thereby forming an opening of a desired shape that penetrates from one surface to the other of the workpiece. [Effects of the Invention]

[0009] With the laser processing apparatus and laser processing method of this disclosure, it is possible to form an opening in a workpiece with high precision. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing a laser processing apparatus according to one embodiment of the present disclosure. [Figure 2] This is a schematic cross-sectional view of a hollow body used in a laser processing method according to one embodiment of the present disclosure. [Figure 3] This figure shows the processing path, appearance, and cross-section of the workpiece in each step of a laser processing method according to one embodiment of the present disclosure. [Figure 4] This figure shows a comparison of the front view, cross-sectional view, and variation in slit width at different plate thicknesses for oblique incidence and perpendicular incidence of the machining area. [Modes for carrying out the invention]

[0011] An embodiment of the laser processing apparatus and laser processing method relating to this disclosure will be described below with reference to the drawings.

[0012] [Laser processing equipment] A laser processing apparatus 1 according to one embodiment of this disclosure will be described below with reference to Figure 1. As shown in Figure 1, the laser processing apparatus 1 comprises a rotary table (mounting base) 10, an irradiation means 20, an imaging means 30, a detection means 40, and a control unit 50.

[0013] A workpiece 100 is placed on the upper surface of the rotary table 10. Although not shown in detail in Figure 1, the workpiece 100 is placed on the rotary table 10 such that the laser beam from the irradiation means 20 is incident at an oblique angle on one surface 101 of the workpiece 100. The rotary table 10 is rotatable about axis X. Therefore, when the rotary table 10 rotates about axis X, the workpiece 100 also rotates along with the rotation of the rotary table 10. That is, when forming openings in multiple regions of the workpiece 100, once the formation of an opening in one region is completed, it is immediately possible to form an opening in another region of the workpiece 100 by rotating the rotary table 10. Examples of materials for the workpiece 100 include nickel alloys such as Inconel. In this embodiment, an example in which a turbine blade is used as the workpiece 100 will be explained.

[0014] The irradiation means 20 irradiates the workpiece 100 placed on the rotary table 10 with laser light. The irradiation means 20 includes a laser oscillator that emits laser light in pulse oscillation, and a laser optical system that condenses the laser light output from the laser oscillator onto the surface or the like of the workpiece 100 and scans the laser light. Laser processing was carried out by combining a high-power femtosecond laser or picosecond laser with a galvanometer scanner, a polygon mirror, or a MEMS mirror capable of scanning the laser at high speed. The laser condition range can be, for example, as shown in Table 1.

[0015]

Table 1

[0016] A gas nozzle 21 is connected to the irradiation means 20. The gas nozzle 21 supplies gas between the irradiation means 20 and the workpiece 100 in order to suppress contamination of the protection window of the irradiation means 20 from the fumes generated during processing. Also, in order to suppress the adhesion of fumes and dust to the workpiece 100, a second gas nozzle (not shown in the figure) may be installed.

[0017] The imaging means 30 is connected to the irradiation means 20 and is preferably a camera coaxial with the irradiation means 20. The imaging means 30 images one side 101 side of the workpiece 100 to obtain image information such as dimensions and the processed surface.

[0018] The detection means 40 is provided on the side of the workpiece 100. The detection means 40 detects the penetration from one side 101 side to the other side 102 side of the workpiece 100 when forming the opening. As the detection means 40, for example, a photosensor can be used. Here, when the workpiece 100 is a turbine blade and a hollow blade is adopted, the side of the workpiece 100 is open. Therefore, when a photosensor is used as the detection means 40 at this time, the detection means 40 detects the light emission (laser light passing through the hole, plasma light emission generated during processing, etc.) leaking from the through-hole when penetrating from one side 101 side to the other side 102 side of the workpiece 100.

[0019] The control unit 50 controls the irradiation of the laser beam by the irradiation means 20. The control unit 50 is configured to acquire image information from the imaging means 30. Accordingly, the control unit 50 controls the irradiation means 20 based on the image information acquired from the imaging means 30 to process the workpiece 100. Further, the control unit 50 is configured to acquire information detected by the detection means 40 about the penetration of the workpiece 100 from one surface 101 side to the other surface 102 side. Accordingly, when the control unit 50 acquires the information detected by the detection means 40 about the penetration, the control unit 50 controls the irradiation means 20 to stop the processing of the workpiece 100.

[0020] The control unit 50 is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium, etc. And a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program as an example. The CPU reads this program into the RAM or the like and executes information processing and arithmetic processing, whereby various functions are realized. Note that the program may be applied in a form pre-installed in the ROM or other storage media, a form provided in a state stored in a computer-readable storage medium, a form distributed via wired or wireless communication means, etc. A computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, etc.

[0021] FIG. 2 is a schematic cross-sectional view showing a turbine blade as the workpiece 100 used in the present embodiment. As shown in FIG. 2, the workpiece 100 is a hollow body 100 having a hollow portion 103. One surface 101 of the workpiece 100 is the surface 101 of the hollow body 100, and the other surface 102 is the back surface 102 of the hollow body 100 facing the hollow portion 103.

[0022] In this embodiment, by irradiating the workpiece 100 with laser light, a tapered opening 104 is formed where the opening area on the other side 102 is smaller than that on the side 101. The opening 104 is rectangular when viewed from the imaging means 30 (upper side in Figure 2). The opening (slit) 105 on the other side 102 of the opening 104 is also rectangular. The shapes of the opening 104 and the slit 105 are not particularly limited and may be round, etc.

[0023] A Teflon material 106 is provided on the back surface 102 of the hollow body 100, in the portion facing the opening 104. Specifically, the Teflon material 106 is provided in a larger area than the opening 104. By protecting the back surface 102 with the Teflon material 106, damage to the back surface 102 of the hollow body 100 by laser light passing through the opening 104 is suppressed. As a shielding material to block laser light in this way, a heat-resistant resin can be used, and the use of fluororesins other than Teflon is also effective.

[0024] Furthermore, if the hollow portion 103 is small, the length of the gap between the back surface 102 of the upper hollow body 100 and the back surface 102 of the lower hollow body 100 in Figure 2 may be short. In this case, if the laser beam is irradiated onto the Teflon material 106 while the processing capacity is high, damage may occur not only to the Teflon material 106 but also to the back surface 102 of the lower hollow body 100. For this reason, it is preferable to control the fluence (pulse energy density) of the laser beam irradiated from the irradiation means 20 in order to prevent damage to the Teflon material 106. Specifically, this can be done by setting the laser beam focusing position closer to the irradiation means 20 than to the processing position. It is preferable to set the laser beam fluence to such an extent that the Teflon material 106 is not damaged no matter how many times the laser beam is irradiated onto it. In addition, by detecting the laser beam that has passed through the through hole with the detection means 40, excessive irradiation of the Teflon material 106 with laser beam is suppressed.

[0025] [Laser processing method] Next, a laser processing method using the laser processing apparatus 1 according to this embodiment will be explained with reference to Figure 3. The laser processing method according to this embodiment is performed by obliquely incidenting a laser beam from the irradiation means 20 onto one surface 101 of the workpiece 100. In this embodiment, the laser beam is irradiated while moving it in a direction intersecting the incident direction, processing is performed in predetermined thicknesses (for example, several μm to several hundred μm) at a time, forming an opening of a desired shape that penetrates from one surface 101 to the other surface 102 of the workpiece 100. The processing process includes a roughing process performed before penetration of the workpiece 100 and a finishing process performed after penetration of the workpiece 100. The finishing process is performed under laser conditions with lower processing capacity than the roughing process. In addition, in this embodiment, a slitting process is performed after the processing process to refine the shape of the slit 105. Each process is performed based on image information from the imaging means 30.

[0026] <Rough processing process> When starting the machining of the workpiece 100, a rough machining process is performed first. The machining path corresponds to the shape of the desired opening. In this embodiment, the machining path in the rough machining process is rectangular (rectangular hatching). Through rough machining, the workpiece 100 is machined sequentially from one side 101 until a penetration occurs in the workpiece 100. Plasma emission occurs during machining.

[0027] <Penetration> If a penetration occurs in the workpiece 100 during processing, the processing is stopped. Penetrations in the workpiece 100 are detected by detecting the light emitted from the through-hole using the detection means 40 described above. At this time, the laser beam conditions are changed in order to perform the subsequent finishing process. Because information such as the thickness of the workpiece 100 becomes clear due to the penetration, it is possible to determine how many more times processing in predetermined thickness increments is needed to obtain an opening of the desired shape.

[0028] <Finishing Process> Once the laser beam conditions have been changed, processing of the workpiece 100 is resumed to perform the finishing process. In the finishing process, the processing path is also rectangular (rectangular hatching). In the finishing process, the remaining predetermined number of processing passes determined during penetration are performed to form an opening 104 of the desired shape. The finishing process is performed under laser conditions with lower processing capacity than the roughing process. For example, the finishing process can be performed with a larger beam diameter than the roughing process. In this way, the inner surface 107 of the opening 104 can be made smooth.

[0029] <Slitting process> After the finishing process is complete, the slitting process is performed. In the slitting process, the slit 105 of the workpiece 100 is edged and hatched at the edges. This removes burrs and other debris that may have formed near the slit 105 during penetration, resulting in a precisely formed slit 105. The slitting process is performed with a smaller beam diameter than the roughing process. By reducing the beam diameter within the appropriate fluence range, it becomes possible to trim unwanted portions with minimal power.

[0030] Once the slit 105 is processed, the formation of the opening 104 is completed. If necessary, the rotary table 10 is rotated to form openings 104 in other areas. Once all openings 104 have been formed, the laser processing is terminated.

[0031] Figure 4 shows a comparison of the front view, cross-sectional view, and variation in slit width with respect to plate thickness at the machining site under oblique incidence and perpendicular incidence conditions. When a laser beam is incident perpendicularly onto a workpiece and processed sequentially to form an opening 204, it is difficult to accurately form the opening 204 if the thickness of the workpiece is unknown. In other words, it is difficult to deal with variations in plate thickness. Specifically, if the thickness of the workpiece is thicker than expected, the workpiece may not be processed enough and penetration may not be possible, or if the thickness of the workpiece is thinner than expected, the workpiece may be processed too much and an opening 204 with a larger width than desired may be formed. In fact, the width variation of the slit 205 due to plate thickness was also large. Thus, when the laser beam is incident perpendicularly to the surface, there was a problem in controlling the shape of the final opening 204 that is formed. In particular, it was difficult to apply this method to structures such as turbine blades where the inner wall may be damaged by penetrating laser beams.

[0032] On the other hand, in this embodiment, the laser beam is incident at an oblique angle on the workpiece surface 101 of the workpiece 100, and the laser beam is moved in a direction intersecting the incident direction while irradiating, thereby processing in predetermined thicknesses (for example, several μm to several hundred μm). As a result, even if the thickness of the workpiece 100 is unknown, a through hole is formed in the workpiece 100 by repeating the processing in predetermined thicknesses. After confirming the formation of the through hole, it is possible to form an opening 104 of the desired shape by performing the processing in predetermined thicknesses a predetermined number of more times on the workpiece. Therefore, compared to the case where the laser beam is incident perpendicularly to the surface, the width variation of the slit 105 due to the plate thickness is reduced, and an opening 104 of the desired shape can be reliably formed in the workpiece 100 robustly to variations in the plate thickness of the workpiece 100. In other words, an opening 104 can be formed in the workpiece 100 with high precision.

[0033] As described above, this embodiment provides the following effects and advantages. In this embodiment, the laser processing apparatus 1 places the workpiece 100 on the mounting table 10 so that the laser beam is incident at an oblique angle to the workpiece surface 101 of the workpiece 100. The control unit 50 irradiates the workpiece 100 while moving the laser beam in a direction intersecting the incident direction, processing it in predetermined thickness increments, and controls the irradiation means 20 to form an opening 104 of a desired shape that penetrates from one side 101 to the other side 102 of the workpiece 100. As a result, even if the thickness of the workpiece 100 is unknown, a through hole is formed in the workpiece 100 by repeatedly processing it in predetermined thickness increments. After confirming the formation of the through hole, it is possible to form an opening 104 of a desired shape by further processing the workpiece 100 in predetermined thickness increments a predetermined number of times. Therefore, compared to the case where the laser beam is incident perpendicularly to the surface, it is possible to reliably form an opening 104 of a desired shape in the workpiece 100 in a robust manner to variations in the thickness of the workpiece 100. In other words, an opening 104 can be formed in the workpiece 100 with high precision.

[0034] When forming a tapered opening 104 in a workpiece 100, where the opening area on the other side 102 is smaller than that on the side 101, it was necessary to know the thickness of the workpiece 100 in order to form the desired shape of the opening 104 by perpendicularly incident the laser beam onto the workpiece 100. On the other hand, in the laser processing apparatus 1 of this embodiment, the laser beam is incident at an angle to the workpiece surface 101 of the workpiece 100, and the workpiece 100 is processed sequentially in predetermined thicknesses from the side 101 to the side 102. Therefore, even if the thickness of the workpiece 100 is unknown, the desired shape of the opening 104 can be formed with high precision simply by repeating the processing a predetermined number of times after confirming penetration of the workpiece 100. Thus, the laser processing apparatus 1 of this embodiment can be suitably used in particular for forming tapered openings 104.

[0035] In this embodiment, by processing the workpiece 100 while acquiring image information of the part being processed from the imaging means 30, it is possible to reliably form an opening 104 of the desired shape as designed.

[0036] In this embodiment, when information indicating penetration is obtained from the detection means 40, the processing of the workpiece 100 is stopped. This prevents excessive laser light from irradiating the inner surface of the workpiece 100 with laser light from the through hole, which could cause damage, for example, if the workpiece 100 is a hollow body 100. Therefore, the laser processing apparatus 1 of this embodiment can be suitably applied to structures such as hollow wings, where the inner surface may be damaged by penetrating laser light.

[0037] Furthermore, by detecting penetration of the workpiece 100, the thickness of the workpiece 100 becomes clear, allowing it to determine how many more times the processing must be repeated in predetermined thickness increments to obtain the desired shape of the opening 104. Therefore, by resuming processing of the workpiece 100 and performing the remaining predetermined number of processing steps, the desired shape of the opening 104 can be formed and the processing can be completed.

[0038] In this embodiment, after detecting penetration and stopping the processing of the workpiece 100, a smooth opening 104 can be formed by performing a finishing process on the opening 104. This makes it possible to form an opening 104 of a desired shape with high precision. The finishing process can be performed, for example, by increasing the beam diameter. If the finishing process is performed with a larger beam diameter, for example, if the workpiece 100 is a hollow body 100, it is possible to suppress the beam light from passing through the penetration hole and damaging the inner surface during the finishing process.

[0039] In the laser processing method according to this embodiment, the workpiece 100 is placed on a mounting table 10 so that the laser beam is incident at an oblique angle to the workpiece surface 101 of the workpiece 100. In the processing step, the laser beam is irradiated while moving in a direction intersecting the incident direction, processing in predetermined thickness increments to form an opening 104 of a desired shape that penetrates from one side 101 to the other side 102 of the workpiece 100. As a result, even if the thickness of the workpiece 100 is unknown, a through hole is formed in the workpiece 100 by repeating the processing in predetermined thickness increments. After confirming the formation of the through hole, it is possible to further process the workpiece 100 in predetermined thickness increments a predetermined number of times to form an opening 104 of a desired shape. Therefore, compared to the case where the laser beam is incident perpendicularly to the surface, it is possible to reliably form an opening 104 of a desired shape in the workpiece 100 in a robust manner to variations in the thickness of the workpiece 100. In other words, an opening 104 can be formed in the workpiece 100 with high precision.

[0040] When a hollow body 100 having a hollow portion 103 is used as the workpiece 100, there is a possibility that the inner surface (back surface) 102 of the hollow body 100 may be damaged by the laser light passing through the opening 104 after the opening 104 is formed. Therefore, in this embodiment, a Teflon material 106 is provided on the portion of the back surface 102 of the hollow body 100 that faces the opening 104. This makes it possible to suppress damage to the back surface 102 of the hollow body 100 by the laser light. It is preferable to control the fluence of the laser light in order to prevent damage to the Teflon material 106. Specifically, this can be done by setting the laser light focusing position closer to the irradiation means 20 than the processing position.

[0041] <Note> The laser processing apparatus and laser processing method described in the embodiments described above can be understood, for example, as follows. A laser processing apparatus (1) according to a first aspect of the present disclosure comprises a mounting table (10) on which a workpiece (100) is placed, an irradiation means (20) for irradiating the workpiece placed on the mounting table with laser light, and a control unit (50) for controlling the irradiation of the laser light by the irradiation means, wherein the workpiece is placed on the mounting table such that the laser light is incident at an oblique angle to one surface of the workpiece, and the control unit controls the irradiation means to process the workpiece in predetermined thickness increments by irradiating the laser light while moving it in a direction intersecting the incident direction, thereby forming an opening (104) of a desired shape that penetrates from one surface to the other of the workpiece.

[0042] In this disclosure, the workpiece is placed on a mounting table so that the laser beam is incident at an oblique angle to the workpiece surface, and the control unit controls the irradiation means to process the workpiece in predetermined thickness increments by irradiating it while moving in a direction intersecting the incident direction, thereby forming an opening of a desired shape that penetrates from one side to the other side of the workpiece. As a result, even if the thickness of the workpiece is unknown, a through hole is formed in the workpiece by repeatedly processing in predetermined thickness increments. After confirming the formation of the through hole, it is possible to form an opening of a desired shape by further processing the workpiece in predetermined thickness increments a predetermined number of times. Therefore, compared to the case where the laser beam is incident perpendicularly to the surface, it is possible to reliably form an opening of a desired shape in the workpiece in a robust manner to variations in the thickness of the workpiece. In other words, an opening can be formed in the workpiece with high precision.

[0043] In the laser processing apparatus according to a second aspect of the present disclosure, in the first aspect, the opening has a tapered shape in which the opening area on one side of the workpiece is smaller than the opening area on the other side.

[0044] When forming a tapered opening in a workpiece where the opening area is smaller on one side than on the other, it was previously necessary to know the thickness of the workpiece in order to form the desired shape by perpendicularly incidenting the laser beam onto the workpiece. On the other hand, in the laser processing apparatus of this disclosure, the laser beam is incident at an angle to the workpiece surface, and the workpiece is processed sequentially in predetermined thicknesses from one side to the other. Therefore, even if the thickness of the workpiece is unknown, an opening of the desired shape can be formed with high precision simply by repeating the processing a predetermined number of times after confirming penetration of the workpiece. Thus, the laser processing apparatus of this disclosure can be suitably used in particular for forming tapered openings.

[0045] A laser processing apparatus according to a third aspect of the present disclosure further comprises, in the first or second aspect, an imaging means (30) for imaging one side of the workpiece, and the control unit processes the workpiece based on image information acquired from the imaging means when forming the opening.

[0046] By processing a workpiece while acquiring image information of the area being processed from an imaging device, it is possible to reliably form an opening of the desired shape according to the design.

[0047] A laser processing apparatus according to a fourth aspect of the present disclosure, in any of the first to third aspects, further comprises a detection means (40) for detecting penetration from one side to the other side of the workpiece when forming the opening, and the control unit stops processing the workpiece when it obtains information that the penetration has been detected from the detection means.

[0048] In this disclosure, when information indicating penetration is obtained from the detection means, the processing of the workpiece is stopped. This prevents excessive laser light from irradiating the inner surface of a hollow workpiece, for example, if the workpiece is hollow, from causing damage. Therefore, the laser processing apparatus of this disclosure can be suitably applied to structures such as hollow wings, where the inner surface may be damaged by penetrating laser light.

[0049] Furthermore, detecting penetration of the workpiece reveals the thickness of the workpiece, allowing it to determine how many more times the processing must be repeated in predetermined thickness increments to obtain the desired shape of the opening. Therefore, by resuming processing the workpiece and performing the remaining predetermined number of processing steps, the desired shape of the opening can be formed and the processing can be completed.

[0050] Furthermore, one possible detection method for detecting penetration is to detect the light emitted when penetration occurs. By using such a method, it is possible to suppress excessive irradiation of the inner surface with laser light that has passed through the through-hole, for example, when the workpiece is a hollow body.

[0051] In the laser processing apparatus according to the fifth aspect of this disclosure, in the fourth aspect, the control unit performs processing in predetermined thicknesses a predetermined number of times after stopping the processing of the workpiece, and the processing performed a predetermined number of times is a finishing process with a lower processing capacity than the processing performed before stopping the processing of the workpiece.

[0052] By detecting penetration and stopping the workpiece machining process, and then performing finishing work on the opening, a smooth-surfaced opening can be formed. This allows for the formation of an opening of a desired shape with high precision. Finishing work can be performed, for example, by increasing the beam diameter. By increasing the beam diameter during finishing, for example, if the workpiece is hollow, it is possible to suppress the beam light from passing through the penetration hole and damaging the inner surface during finishing work.

[0053] A laser processing method according to a sixth aspect of this disclosure includes a placement step of placing a workpiece on a mounting table such that laser light from an irradiation means is incident obliquely on one surface of the workpiece, and a processing step of irradiating the workpiece with laser light while moving it in a direction intersecting the incident direction to process it in predetermined thickness increments, thereby forming an opening of a desired shape that penetrates from one surface to the other of the workpiece.

[0054] This disclosure includes a processing step in which a workpiece is placed on a mounting table so that a laser beam is incident on the workpiece surface at an oblique angle, and the laser beam is irradiated while moving in a direction intersecting the incident direction, thereby processing in predetermined thickness increments to form an opening of a desired shape that penetrates from one side to the other side of the workpiece. As a result, even if the thickness of the workpiece is unknown, a through hole is formed in the workpiece by repeatedly processing in predetermined thickness increments. After confirming the formation of the through hole, it is possible to form an opening of a desired shape by further processing in predetermined thickness increments a predetermined number of times. Therefore, compared to the case where the laser beam is incident perpendicular to the surface, it is possible to reliably form an opening of a desired shape in the workpiece in a robust manner to variations in the thickness of the workpiece. In other words, an opening can be formed in the workpiece with high precision.

[0055] In the laser processing method according to the seventh aspect of this disclosure, in the sixth aspect, a hollow body (100) having a hollow portion (103) is used as the workpiece, one surface (101) of the hollow body and the other surface (102) of the hollow body facing the hollow portion, and a Teflon material (106) is provided on the portion of the back surface of the hollow body facing the opening.

[0056] When a hollow body having a hollow portion is used as the workpiece, there is a possibility that the inner surface (back surface) of the hollow body may be damaged by laser light passing through the opening after the opening has been formed. Therefore, in this disclosure, a Teflon material is provided on the portion of the back surface of the hollow body that faces the opening. This makes it possible to suppress damage to the back surface of the hollow body by laser light. It is preferable to control the fluence of the laser light in order to prevent damage to the Teflon material. Specifically, this involves setting the laser light focusing position on the irradiation means side of the processing position. [Explanation of symbols]

[0057] 1. Laser processing device 10 Rotating Table (Mounting Platform) 20 Irradiation means 21 Gas nozzle 30 Imaging means 40 Detection means 50 Control Unit 100 Workpiece (hollow body) 101 Surface (single surface, processed surface) 102 Reverse side (other side) 103 Hollow part 104 Opening 105 slits 106 Teflon material 107 Inner self X axis

Claims

1. A mounting table on which the workpiece is placed, An irradiation means for irradiating the workpiece placed on the mounting table with laser light, The system comprises a control unit that controls the irradiation of the laser light by the irradiation means, The workpiece is placed on the aforementioned stand such that the laser beam is incident at an oblique angle on one surface of the workpiece. The control unit controls the irradiation means to process the workpiece in predetermined thickness increments by irradiating it while moving the laser beam in a direction intersecting the incident direction, thereby forming an opening of a desired shape that penetrates from one side to the other side of the workpiece.

2. The laser processing apparatus according to claim 1, wherein the opening has a tapered shape in which the opening area on the other side of the workpiece is smaller than the opening area on the one side.

3. The system further includes an imaging means for imaging one side of the workpiece, The laser processing apparatus according to claim 1, wherein the control unit processes the workpiece based on image information acquired from the imaging means when forming the opening.

4. In forming the aforementioned opening, the following means is further provided to detect penetration from one side to the other side of the workpiece: The laser processing apparatus according to any one of claims 1 to 3, wherein the control unit stops processing the workpiece when it obtains information from the detection means that penetration has been detected.

5. The control unit, after stopping the processing of the workpiece, performs the processing in predetermined thicknesses a predetermined number of times. The laser processing apparatus according to claim 4, wherein the predetermined number of processing steps is a finishing process with a lower processing capacity than the processing before stopping the processing of the workpiece.

6. A mounting step in which the workpiece is placed on a mounting table such that the laser beam from the irradiation means is incident at an oblique angle on one surface of the workpiece, A laser processing method comprising a processing step of irradiating the workpiece with the laser light while moving it in a direction intersecting the incident direction, thereby processing it in predetermined thicknesses to form an opening of a desired shape that penetrates from one side to the other side of the workpiece.

7. As the workpiece, a hollow body having a hollow portion is used. One surface is the surface of the hollow body, and the other surface is the back surface of the hollow body facing the hollow portion. The laser processing method according to claim 6, wherein a Teflon material is provided on the back surface of the hollow body in a portion facing the opening.

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