JP2005161387A - Laser beam machining apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus capable of performing high-precision micro-fabrication in a narrow area. <P>SOLUTION: The laser beam machining apparatus is equipped with: a measuring laser oscillator 10 that generates a measuring laser beam 11 like an He-Ne laser with a wavelength of 0.63 μm; a machining laser oscillator 15 that generates a machining laser beam 16 like a YAG laser with a wavelength of 1.06 μm; a light condensing head 30 that has a condensing lens 31 for converging laser beams 11, 16; an NC machine tool 40 that relatively moves and rotatably drives the light condensing head 30 relative to the inner face 91 of a bore; a CCD camera 60 that photographs the irradiation part 12 of the measuring laser beam 11 emitted to the inner face 91 of the bore; a computer 80 that, on the basis of the irradiation diameter, discriminates whether or not the relative distance of the condensing lens 31 to the irradiation part 12 is a distance capable of securing the focal depth of the machining laser beam 16; and an NC controller 50 that, on the basis of the discrimination result, controls the NC machine tool 40 in the manner relatively moving the condensing head 30 to the irradiation part 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser processing apparatus and a laser processing method for performing fine processing using a laser beam on a portion to be processed in a narrow portion such as the inside of a cylindrical body such as a bore inner surface of a cylinder of an internal combustion engine.

  Conventionally, in order to prevent seizure of a cylinder of an automobile engine or the like, an oil reservoir is provided by forming a recess in the bore inner surface of the cylinder by honing, but in recent years, this honing has been replaced. A method of forming a recess by finely processing the inner surface of a bore using laser light is known (see, for example, Patent Document 1).

  However, if there are variations in workpiece setting accuracy, bore diameter, etc. to the laser processing equipment, the processed part will be displaced with respect to the condensing lens that collects the laser beam due to such variations, so that a certain machining quality will be achieved. In some cases, the depth of focus of the laser beam for processing to such an extent that the depth of the dent and the width can be obtained cannot be secured, and the function of preventing the oil sump from burning is deteriorated.

On the other hand, in order to secure a predetermined depth of focus of the processing laser light, a method of measuring the relative distance of the condensing lens with respect to the processing part using a laser displacement meter or the like can be considered. In a certain cylinder, there is a possibility that the laser displacement meter may interfere with the inner surface of the bore, so that there are restrictions on the outer shape and layout of the laser displacement meter. In addition, since the installation accuracy of the laser displacement meter affects the measurement accuracy of the relative distance of the condenser lens with respect to the workpiece, it is required to install the laser displacement meter with high accuracy.
Japanese Unexamined Patent Publication No. 7-040068

An object of this invention is to provide the laser processing apparatus and laser processing method which can perform a highly accurate fine process in a narrow site | part.
In order to achieve the above object, according to the present invention, a measuring laser beam generating means for generating a measuring laser beam, and a processing laser beam generating for generating a processing laser beam having a wavelength different from that of the measuring laser beam are provided. Means, condensing means having a condensing lens for condensing the measurement laser light and the processing laser light, and driving means for moving and rotating the condensing means relative to the part to be processed. Detecting means for detecting an irradiation diameter of the laser beam for measurement irradiated on the processed portion; and a relative position of the condenser lens with respect to the processed portion based on the irradiation diameter detected by the detecting means A determination unit that determines whether the distance is a distance at which a focal depth of the laser beam for processing can be secured, and the condensing unit with respect to the workpiece based on a determination result by the determination unit Move relative Sea urchin said control means for controlling the driving means, the laser processing apparatus having a are provided.

  In order to achieve the above object, according to the present invention, the step of irradiating the processing portion with the measurement laser via the condenser lens, and the irradiation diameter of the measurement laser light irradiated on the processing portion And whether or not the relative distance of the condensing lens with respect to the workpiece is a distance that can ensure the depth of focus of the processing laser beam based on the detected irradiation diameter. A step of determining, a step of moving the condensing lens relative to the portion to be processed based on the determination result, and a processing laser beam having a wavelength different from that of the measuring laser. And a step of irradiating the workpiece via a laser beam.

  In the present invention, when laser processing is performed, first, the measurement laser light generating means irradiates the measurement laser light having a wavelength different from that of the processing laser light, and the detection means irradiates the measurement laser light applied to the workpiece. Whether or not the relative distance of the condensing lens with respect to the workpiece is a distance that can secure the depth of focus of the processing laser light based on the detected irradiation diameter. Determine whether. Then, based on the determination result, the control means controls the driving means so as to move the light collecting means relative to the processed portion, and then the processing laser light generating means is applied to the processed portion. On the other hand, a processing laser beam is irradiated.

  Thus, before the processing laser light is irradiated, the relative distance of the condensing lens with respect to the processing part is a distance that can secure the focal depth of the processing laser light using the measurement laser light. By determining whether or not and feeding back the determination result to the position control of the condenser lens, the focal depth of the processing laser beam is secured to obtain a certain processing quality of the processing portion, and high accuracy is achieved. Fine processing can be performed.

  In addition, for example, when performing both position measurement and processing using the same laser beam, it is necessary to split the laser beam, which leads to an increase in the size of the condensing means having a condensing lens. In the present invention, in particular, by using a measurement laser beam different from the processing laser beam, it is possible to reduce the size of the light converging means, and to perform highly accurate fine processing in a narrow part. Become. Further, since both the measurement laser beam and the processing laser beam are condensed by the same condenser lens, there is no problem of installation accuracy as in the case of the laser displacement meter described above.

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

[First Embodiment]
FIG. 1 is a schematic view showing the entire laser processing apparatus according to the first embodiment of the present invention, FIG. 2 (A) is a perspective view showing an inner surface of a bore of a cylinder as a workpiece in the embodiment of the present invention, and FIG. 2B is an enlarged front view of the recess formed in the bore inner surface of FIG. 2A, FIG. 2C is a cross-sectional view of the recess along the IIC-IIC line of FIG. (A) is an enlarged sectional view of the condensing head and the bore inner surface of the laser processing apparatus according to the first embodiment of the present invention, FIG. 3 (B) is a sectional view taken along line IIIB-IIIB in FIG. 4 (A) and 4 (B) are diagrams showing an image of the irradiation unit captured by the CCD camera of the laser processing apparatus according to the first embodiment of the present invention, and FIG. 4 (A) shows variations in workpieces. 4B is a diagram showing an image when there is variation in the workpiece, and FIG. 5 is a diagram showing the image according to the first embodiment of the present invention. FIG. 6 is a flowchart showing the procedure of the laser processing operation by the laser processing apparatus according to the first embodiment of the present invention.

  First, a cylinder 90 that is a workpiece (workpiece) of the laser machining apparatus 1 according to the present embodiment will be described. The cylinder 90 is a cylinder used in an internal combustion engine such as an automobile engine, for example, as shown in FIG. As shown, it has a substantially cylindrical shape as a whole. When the cylinder 90 is used as an internal combustion engine, the inner surface 91 of the bore 91 is prevented as shown in FIG. A plurality of depressions 92 are formed on the (inner peripheral surface) to provide an oil sump. As shown in FIGS. 2B and 2C, each recess 92 is formed with a predetermined width w and depth h. If the width w and the depth h of the dent 92 are too large or too small, the function of preventing seizure as an oil reservoir will be reduced. 2A is a view of the bore inner surface 91 viewed from the central axis of the cylinder 90 in order to clarify the state of the bore inner surface 91. FIG.

  Next, the laser processing apparatus 1 according to the present embodiment will be described. This laser processing apparatus 1 is an apparatus for forming a plurality of hollow portions 92 in the bore inner surface 91 of the cylinder 90 by laser processing. As shown, a measuring laser oscillator 10 (measuring laser light generating means) that generates a measuring laser beam 11 and a processing laser oscillator 15 that generates a processing laser beam 16 having a wavelength different from that of the measuring laser beam 11 ( Processing laser light generating means), a condensing head 30 (condensing means) having a condensing lens 31 for condensing the laser beams 11 and 16, and the condensing head 30 relative to the bore inner surface 91. An NC machine tool 40 (driving means) that is moved and rotated to the CCD, a CCD camera 60 (detecting means) that images the measurement laser light irradiation unit 12 irradiated on the bore inner surface 91, and The imaged irradiation diameter of the irradiation unit 12 is extracted, and based on the irradiation diameter, the relative distance of the condenser lens 31 with respect to the irradiation unit 12 on the bore inner surface 91 can ensure the focal depth of the processing laser beam 16. The NC machine tool 40 so as to move the condensing head 30 relative to the irradiation unit 12 of the bore inner surface 91 based on the computer 80 (determination means) for determining whether or not the distance is present and the determination result. And an NC controller 50 for controlling.

  The laser oscillator 10 for measurement of the laser processing apparatus 1 is an oscillator that generates the measurement laser light 11 used for determining the relative distance of the condenser lens 31 with respect to the processing portion of the bore inner surface 91. The measurement laser beam 11 oscillated by the measurement laser oscillator 10 is, for example, a visible light laser such as a He—Ne laser having a wavelength of 0.63 μm. The measurement laser beam 11 oscillated from the measurement laser oscillator 10 is reflected by the first mirror 20 and guided into the condensing head 30. Note that the measurement laser light of the present invention is not limited to a He—Ne laser, and for example, a semiconductor laser light such as a GaAs laser or an InGaP laser can be used.

The processing laser oscillator 15 of the laser processing apparatus 1 is an oscillator that generates the processing laser light 16 for processing the bore inner surface 91 to form the recess 92. The processing laser light 16 oscillated by the processing laser oscillator 15 is, for example, a processing laser such as a YAG laser light having a wavelength of 1.06 μm. The processing laser light of the present invention is not limited to the YAG laser light, and for example, processing laser light such as CO ₂ laser, argon laser, excimer laser, ruby leather, glass laser, CO laser, iodine laser, etc. Can be used.

  The processing laser light 16 is oscillated from the processing laser oscillator 15 as a pulse wave having an average output of 40 W and a repetition rate of 35 kHz, reflected by the first half mirror 21 and guided into the condensing head 30. As shown in FIG. 1, the first half mirror 21 is capable of reflecting the processing laser beam 16 on one surface and receiving the measuring laser beam 11 incident from the other surface. It can be transmitted through the surface.

  The laser oscillators 10 and 15, the first mirror 20, and the first half mirror 21 described above are reflected by the first mirror 20 and transmitted through the first half mirror 21. The processing laser beam 16 reflected by the first half mirror 21 is disposed so as to be substantially coaxial.

  The condensing head 30 of the laser processing apparatus 1 is a substantially cylindrical body having a diameter smaller than the bore diameter of the cylinder 90, as shown in FIG. As shown in FIG. 3A, the condensing head 30 includes a condensing lens 31, a second half mirror 33 (partial transmission means), and a second mirror 34 (reflection means). Are placed on the optical axes of the measurement laser beam 11 and the processing laser beam 16.

  The condensing lens 31 of the condensing head 30 is a lens that condenses the measurement laser light 11 and the processing laser light 16 that are mixedly incident from above the condensing head 30. Is arranged. The second half mirror 33 located below the condenser lens 31 transmits the measurement laser light 11 collected by the condenser lens 31 and is condensed by the condenser lens 31. The processing laser beam 16 is installed so as to be reflected and irradiated on the bore inner surface 91. Further, the second mirror 34 positioned below the second half mirror 33 reflects the measurement laser beam 11 transmitted through the second half mirror 33 to the bore inner surface 91 and irradiates the irradiation unit 12. It is installed as follows. As shown in FIG. 3B, the second half mirror 33 and the second mirror 34 are configured such that the optical axis of the measurement laser beam 11 reflected by the second mirror 34 is the second half mirror. It is installed so as to be positioned forward in the θ rotation direction with respect to the optical axis of the processing laser beam 16 reflected by 33. As will be described later, since the NC machine tool 40 rotates the condensing head 30 in the θ direction after the determination by the computer 80, the irradiation unit 12 of the bore inner surface 91 irradiated with the measurement laser beam 11 and the processing laser The portion to be processed by laser with the light 16 substantially matches.

  Further, the condensing head 30 is supported by the NC machine tool 40 via a support portion 41. Then, the actuator (not shown) of the NC machine tool 40 is driven based on the control command of the NC controller 90 connected to the NC machine tool 40, so that the light condensing head 30 is moved in the XYZ axial directions. (See FIG. 3A) and can be rotated in the θ direction (see FIG. 3B).

  Furthermore, the laser processing apparatus 1 according to the present embodiment includes a CCD camera 60 for imaging the irradiation unit 12 of the measurement laser light 11 irradiated to the bore inner surface 91 via the condensing head 30.

  As shown in FIGS. 1 and 3A, the CCD camera 60 includes a second mirror 34 installed in the above-described condensing head 30 and a third mirror provided above the condensing head 30. Due to the reflection from the half mirror 70, it is possible to image the irradiation part 12 of the measurement laser beam 11 irradiated to the bore inner surface 91, and it is possible to image the irradiation part 12 of the bore inner surface 91 from the outside of the condensing head 30. It is like that. Note that the third half mirror 70 reflects the image of the irradiation unit 12 on one surface and allows the measurement laser beam 11 and the processing laser beam 16 to pass from the other surface to one surface. .

  The CCD camera 60 is connected to a computer 80, and an image of the irradiation unit 12 captured by the CCD camera 60 can be input to the computer 80. Then, the computer 80 of the laser processing apparatus 1 performs image processing such as binarization on the image input from the CCD camera 60 to extract the irradiation diameter of the irradiation unit 12. Furthermore, the computer 80 determines whether the relative distance of the condensing lens 31 with respect to the irradiation unit 12 is a distance that can secure the depth of focus of the processing laser light 16 based on the extracted irradiation diameter. .

  As a specific method of determination by the computer 80, the irradiation diameter of the irradiation unit 12 imaged by the CCD camera 60 is a relatively small irradiation diameter R1 as shown in FIG. When the diameter R1 is located in the area IVA shown in FIG. 5, there is no variation in the workpiece setting accuracy and the bore diameter, the bore inner surface 91 is not displaced from the condensing head 30, and the relative distance is It is determined that the depth of focus of the processing laser beam 16 can be ensured, and it is determined that a hollow portion having processing quality (width w and depth h) that can ensure a seizure prevention function can be formed. .

  On the other hand, for example, the irradiation diameter of the irradiation unit 12 imaged by the CCD camera 60 is a relatively large irradiation diameter R2 as shown in FIG. 4B, and the irradiation diameter R2 is shown in FIG. When located in the region IVB, for example, as shown in FIGS. 3 (A) and 3 (B), the bore inner surface 91 of the cylinder 90 is not a perfect circle, but is expanded to the right by the amount of deviation B in FIG. It is formed in such an ellipse, the bore inner surface 91 is displaced with respect to the condensing head 30, and it is determined that the relative distance is a distance at which the depth of focus of the processing laser beam 16 cannot be secured, and a burn-in prevention function It is determined that the hollow portion having the processing quality capable of securing the thickness cannot be formed.

  Further, the computer 80 is connected to the NC controller 50 so that the determination result can be fed back to the position control of the condensing head 30 by the NC machine tool 40. For example, in the case where the bore inner surface 91 is displaced by a deviation amount B with respect to the condensing head 30 as shown in FIGS. 3 (A), 3 (B) and 4 (B), the NC controller The NC machine tool 40 controls the NC machine tool 40 so that 50 corrects the deviation amount B, and moves the condensing head 30 in the positive direction of the Y-axis, that is, the NC machine tool moves the condensing head 30 closer to the irradiation unit 12. 40 is driven.

  Below, with reference to FIG. 6, the specific operation | movement of the laser processing by this laser processing apparatus 1 is demonstrated.

  First, as shown in FIG. 1, when the cylinder 90 (work) is set at a predetermined position of the laser processing apparatus 1, the condensing head 30 is placed in the bore of the cylinder 90 based on the control command of the NC controller 50. The NC machine tool 40 is driven to insert (step S10 in FIG. 6).

  Next, the measurement laser oscillator 10 oscillates the measurement laser beam 11, and the measurement laser beam 11 is reflected by the first mirror 20 and passes through the first and third half mirrors 21 and 70. , And enters the condensing head 30. The measurement laser beam 11 incident on the condensing head 30 is condensed by the condensing lens 31, passes through the second half mirror 33, is reflected by the second mirror 34, and is formed on the inner surface of the bore of the cylinder 90. 91 of the irradiation unit 12 is irradiated (step S20).

  Next, the CCD camera 60 captures an image of the irradiation unit 12 reflected by the second mirror 34 and the third half mirror 70 (step S30).

  Next, the image of the irradiation unit 12 picked up by the CCD camera 60 is taken into the computer 80 and subjected to image processing, and the irradiation diameter of the irradiation unit 12 is extracted (step S40).

  Next, the computer 80 is configured such that the relative distance of the condenser lens 31 with respect to the irradiation unit 12 is such that the focal depth of the processing laser beam 16 can be secured based on the extracted irradiation diameter of the irradiation unit 12. It is determined whether or not there is (step S50).

  In this determination, if it is determined that the relative distance is a distance that can secure the depth of focus of the processing laser beam 16 (YES in step S50), the second half mirror is based on the determination result. The NC controller 50 controls the NC machine tool 40 so that the optical axis of the processing laser beam 16 reflected by the beam 21 is directed to the irradiation unit 12, and the NC machine tool rotates the condensing head 30 in the θ direction. 40 is driven (step S60).

  On the other hand, in the above determination, when it is determined that the relative distance is a distance at which the focal depth of the processing laser beam 16 cannot be secured (NO in step S50), based on the determination result, The NC controller 50 controls the NC machine tool 40 to correct the position of the condensing head 30 so that the relative distance is a distance that can secure the focal depth of the processing laser beam 16 (step S70). When the position correction of the condensing head 30 is completed, the NC controller 50 controls the NC machine tool 40 so that the optical axis of the processing laser beam 16 faces the irradiation unit 12, and the condensing head 30 is moved. The NC machine tool 40 is driven to rotate in the θ direction (step S60).

  When the optical axis of the processing laser beam 16 is directed to the irradiation unit 12, the processing laser oscillator 15 oscillates the processing laser beam 16, and the processing laser beam 16 is reflected by the first half mirror 21. Then, the light passes through the half mirror 70 and enters the condensing head 30. The processing laser light 16 incident on the condensing head 30 is condensed by the condensing lens 31, reflected by the second half mirror 33, and irradiated to the irradiation unit 12 of the bore inner surface 91 of the cylinder 90. (Step S80). During the irradiation of the processing laser beam 16, the NC machine tool 40 is driven so that the processing laser beam 16 is irradiated at a processing speed of about 15 m / min, so that a depression 92 is formed in the irradiation unit 12. .

  By repeating the operations of steps S10 to S80 over the entire circumference of the bore inner surface 91, for example, a plurality of uppermost recesses 92 shown in FIG. . Then, the NC machine tool 40 moves the condensing head 30 in the Z-axis direction and repeats the operations of the above-described steps S10 to S80 over the entire circumference of the bore inner surface 91, for example, as shown in FIG. A plurality of second-stage depressions 92 are formed. Similarly, the NC machine tool 40 moves the condensing head 30 in the Z-axis direction and repeats the operations of steps S10 to S80 over the entire circumference of the bore inner surface 91, for example, as shown in FIG. A plurality of indentations 92 in the third and fourth stages shown are formed.

  For example, the pitch between the optical axis of the processing laser beam 16 reflected by the second half mirror 33 and the optical axis of the measurement laser beam 11 reflected by the second mirror 34 is the bore of the cylinder 90. The processing laser in step S80 described above, for example, by arranging the first half mirror 33 and the second mirror 34 so as to be substantially the same as the pitch of the plurality of hollow portions 92 formed on the inner surface 91. During the formation of the depression 92 by the light 16, the above-described operations of steps S10 to S50 may be performed by the measurement laser beam 11 whose optical axis is directed to the next irradiation unit, thereby improving the productivity of laser processing. Can be increased.

  As described above, in the laser processing apparatus and the laser processing method according to the present embodiment, at the time of laser processing, measurement laser light having a wavelength different from the processing laser light is first emitted from the measurement laser oscillator, and the CCD camera The irradiation part of the measurement laser light irradiated on the inner surface of the bore is imaged, and the computer extracts the irradiation diameter of the imaged irradiation part, and based on the irradiation diameter, the relative distance of the condenser lens to the irradiation part However, it is determined whether it is the distance which can ensure the focal depth of the laser beam for processing. Then, based on the determination result, the NC controller controls the NC machine tool to move the condensing head relative to the irradiation unit, and then the processing laser oscillator processes the irradiation unit. Irradiate laser light.

  Thus, before the processing laser light is irradiated, the relative distance of the condensing lens with respect to the irradiated portion is determined by using the measurement laser light having a wavelength different from that of the measurement laser light. Determining whether or not the depth is a distance that can be secured, and feeding back the determination result to the position control of the condensing head, so that a fixed processing quality can be obtained in the irradiation unit. The depth is ensured and high-precision fine processing can be performed.

  In addition, for example, when both position measurement and processing are performed using the same laser beam, it is necessary to split the laser beam, which leads to an increase in the size of the condensing head. In particular, by using a measurement laser beam different from the processing laser beam, it becomes possible to reduce the size of the condensing head, and in a narrow part such as the inside of a cylindrical body such as a cylinder of an internal combustion engine. High-precision fine processing can be performed. Further, since both the measurement laser beam and the processing laser beam are condensed by the same condenser lens, there is no problem of installation accuracy as in the case of the laser displacement meter described above.

  In the laser processing apparatus according to the present embodiment, the second half is arranged such that the condensing head transmits the measurement laser light collected by the condensing lens and reflects the processing laser light. By having a mirror and a second mirror arranged so as to reflect the measurement laser beam that has passed through the second half mirror, a cylindrical shape such as the inner surface of the bore is utilized by utilizing the reflection of the laser beam. The structure for irradiating the measuring laser beam and the processing laser beam to the inner surface of a narrow part such as a body can be reduced in size, and the condensing head that enters the narrow part can be configured compactly. .

[Second Embodiment]
FIG. 7A is an enlarged cross-sectional view of the condensing head and the bore inner surface of the laser processing apparatus according to the second embodiment of the present invention, and FIG. 7B is a cross-section taken along the line VIIB-VIIB of FIG. FIG.

  The laser processing apparatus 1b according to the second embodiment of the present invention is the first embodiment in that the measurement laser beam 11 and the processing laser beam 16 are irradiated non-coaxially and the internal configuration of the condensing head 30b is different. Unlike the laser processing apparatus 1 according to the embodiment, other configurations are the same as those of the laser processing apparatus 1 according to the first embodiment. Below, only the difference with the laser processing apparatus 1 which concerns on 1st Embodiment is demonstrated about the laser processing apparatus 1b which concerns on 2nd Embodiment.

  First, in the laser processing apparatus 1b according to the present embodiment, as shown in FIG. 7A, the measurement laser light 11 and the processing laser light 16 incident on the condensing head 30b are non-coaxial. Further, the laser oscillators 10 and 15, the first mirror 20, and the first half mirror 21 (all not shown) are arranged.

  Then, inside the condensing head 30b where these laser beams 11 and 16 are incident non-coaxially, as shown in FIG. 7A, a bifocal lens 32 (condensing lens) and a segment mirror 35 are provided. And are installed. The bifocal lens 32 of the condensing head 30b includes a first focal portion that condenses the measurement laser light 11 and a second focal portion (both not shown) that condenses the processing laser light 16. The double-focus lens 32 so that the first focal portion coincides with the optical axis of the measurement laser beam 11 and the second focal portion coincides with the optical axis of the processing laser beam 16. Is arranged.

  The segment mirror 35 positioned below the bifocal lens 32 includes a first segment portion 36 (first reflecting means) that reflects the measurement laser beam 11 and a second segment that reflects the processing laser beam 16. A segment portion 37 (second reflecting means), the first segment portion 36 coincides with the optical axis of the measurement laser beam 11, and the second segment portion 37 is the light of the processing laser beam 16. The segment mirror 35 is arranged so as to coincide with the axis. As shown in FIG. 7B, the segment mirror 35 is used for processing in which the optical axis of the measurement laser beam 11 reflected by the first segment portion 36 is reflected by the second segment portion 37. The first segment portion 36 is disposed with respect to the second segment portion 37 so as to be located forward of the optical axis of the laser beam 16 in the θ rotation direction.

  The laser processing operation by the laser processing apparatus 1b is the same as the operation by the laser processing apparatus 1 of the first embodiment described with reference to FIG. 6, and the NC machine tool 40 is driven and set. When the condensing head 30b is inserted into the bore of the cylinder 90 (work), the measurement laser oscillator 10 oscillates the measurement laser beam 11, and the measurement laser beam 11 is connected to the first mirror 20 and the first and second laser beams. The light enters the condensing head 30b via the third half mirrors 21 and 70.

  Then, unlike the first embodiment, the measurement laser beam 11 incident on the condensing head 30b is condensed at the first focal point of the bifocal lens 32 and then the segment mirror 35 in the present embodiment. The first segment portion 36 is reflected to irradiate the irradiation portion 12 of the bore inner surface 91 of the cylinder 90.

  Next, the CCD camera 60 images the irradiation unit 12 on the bore inner surface 91 via the second mirror 34 and the third half mirror 70, and the computer 80 performs image processing on the image, and the irradiation is performed. The irradiation diameter of the unit 12 is extracted, and further, the relative distance of the condenser lens 31 with respect to the irradiation unit 12 can ensure the focal depth of the processing laser beam 16 based on the extracted irradiation diameter of the irradiation unit 12. It is determined whether the distance is about a certain distance.

  In this determination, when it is determined that the relative distance is a distance at which the focal depth of the processing laser light 16 can be secured, the optical axis of the processing laser light 16 is based on the determination result. 12, the NC controller 50 controls the NC machine tool 40, and the NC machine tool 40 is driven to rotate the condensing head 30 b in the θ direction.

  On the other hand, in the above determination, when it is determined that the relative distance is a distance at which the focal depth of the processing laser beam 16 cannot be secured, the NC controller 50 determines that the NC machine tool is based on the determination result. 40, the position of the condensing head 30b is corrected so that the relative distance is a distance that can secure the depth of focus of the processing laser light 16, and then the optical axis of the processing laser light 16 is adjusted. The NC controller controls the NC machine tool 40 so as to face the irradiation unit 12, and the NC machine tool 40 is driven to rotate the condensing head 30b in the θ direction.

  When the optical axis of the processing laser beam 16 is directed to the irradiation unit 12, the processing laser oscillator 15 oscillates the processing laser beam 16, and the processing laser beam 16 is transmitted to the first half mirror 21 and the third half laser beam. The light enters the condensing head 30b through the mirror 70.

  Then, unlike the first embodiment, the processing laser beam 16 incident on the condensing head 30b is condensed at the second focal point of the bifocal lens 32 and then segmented by the segment mirror. Reflected by the second segment portion 37 of 35 and irradiated to the irradiation portion 12 of the bore inner surface 91, a hollow portion 92 is formed in the bore inner surface 91.

  As described above, in the laser processing apparatus and the laser processing method according to the present embodiment, at the time of laser processing, measurement laser light having a wavelength different from the processing laser light is first emitted from the measurement laser oscillator, and the CCD camera The irradiation part of the measurement laser light irradiated on the inner surface of the bore is imaged, and the computer extracts the irradiation diameter of the imaged irradiation part, and based on the irradiation diameter, the relative distance of the condenser lens to the irradiation part However, it is determined whether it is the distance which can ensure the focal depth of the laser beam for processing. Then, based on the determination result, the NC controller controls the NC machine tool to move the condensing head relative to the irradiation unit, and then the processing laser oscillator processes the irradiation unit. Irradiate laser light.

  Thus, before the processing laser light is irradiated, the relative distance of the condensing lens with respect to the irradiated portion is determined by using the measurement laser light having a wavelength different from that of the measurement laser light. The depth of focus of the processing laser light that can obtain a certain processing quality of the irradiation unit by determining whether or not the distance can be secured and feeding back the determination result to the position control of the condensing head Is ensured, and high-precision fine processing can be performed.

  In addition, for example, when both position measurement and processing are performed using the same laser beam, it is necessary to split the laser beam, which leads to an increase in the size of the condensing head. In particular, by using a measurement laser beam different from the processing laser beam, it becomes possible to reduce the size of the condensing head, and in a narrow part such as the inside of a cylindrical body such as a cylinder of an internal combustion engine. High-precision fine processing can be performed. Further, since both the measurement laser beam and the processing laser beam are condensed by the same condenser lens, there is no problem of installation accuracy as in the case of the laser displacement meter described above.

  In the laser processing apparatus according to the present embodiment, the condensing head includes a first segment unit that reflects the measurement laser beam collected by the first focal unit of the bifocal lens, and a bifocal point. By having a segment mirror having a second segment portion that reflects the processing laser beam collected at the second focal portion of the lens, a tube such as an inner surface of the bore is utilized by utilizing the reflection effect of the laser beam. The structure that irradiates the measuring laser beam and the processing laser beam to the inner surface of a narrow part such as a body can be miniaturized, and the condensing head that enters the narrow part can be made compact. Become.

The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

FIG. 1 is a schematic view showing the entire laser processing apparatus according to the first embodiment of the present invention. FIG. 2A is a perspective view showing a bore inner surface of a cylinder which is a workpiece in the embodiment of the present invention, and FIG. 2B is a hollow portion formed on the bore inner surface of FIG. FIG. 2C is a cross-sectional view of the recess along the line IIC-IIC in FIG. FIG. 3A is an enlarged cross-sectional view of the condensing head and the bore inner surface of the laser processing apparatus according to the first embodiment of the present invention, and FIG. 3B is a IIIB-IIIB line in FIG. FIG. 4 (A) and 4 (B) are diagrams showing an image of an irradiation unit imaged by the CCD camera of the laser processing apparatus according to the first embodiment of the present invention. FIG. 4 (A) shows a variation in the workpiece. FIG. 4B shows an image when there is variation in the workpiece. FIG. 5 is a graph showing the relationship between the irradiation diameter and the amount of deviation of the bore inner surface in the first embodiment of the present invention. FIG. 6 is a flowchart showing the procedure of the laser processing operation by the laser processing apparatus according to the first embodiment of the present invention. FIG. 7A is an enlarged cross-sectional view of the condensing head and the bore inner surface of the laser processing apparatus according to the second embodiment of the present invention, and FIG. 7B is a line VIIB-VIIB in FIG. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus 10 ... Measuring laser oscillator 11 ... Measuring laser beam 12 ... Irradiation part 15 ... Processing laser oscillator 16 ... Processing laser beam 20 ... 1st mirror 21 ... 2nd half mirror 30 ... Condensing Head 31 ... Condenser lens 32 ... Double focus lens 33 ... Second mirror (reflecting means)
34 ... Second half mirror (partial transmission means)
35 ... Segment mirror 36 ... First segment (first reflecting means)
37 ... 2nd segment (2nd reflection means)
40 ... NC
DESCRIPTION OF SYMBOLS 50 ... NC controller 60 ... CCD camera 70 ... 3rd half mirror 80 ... Computer 90 ... Cylinder 91 ... Bore inner surface 92 ... Recessed part

Claims (6)

A measuring laser beam generating means for generating a measuring laser beam;
A processing laser beam generating means for generating a processing laser beam having a wavelength different from that of the measurement laser beam;
A condensing unit having a condensing lens for condensing the measurement laser beam and the processing laser beam;
Driving means for moving and rotating the light collecting means relative to the workpiece; and
Detection means for detecting an irradiation diameter of the measurement laser light irradiated to the workpiece;
Based on the irradiation diameter detected by the detection means, it is determined whether or not the relative distance of the condenser lens with respect to the processed portion is a distance that can ensure the focal depth of the processing laser light. A determination means;
A laser processing apparatus comprising: a control unit that controls the driving unit so as to move the condensing unit relative to the workpiece based on a determination result by the determination unit. The determination means includes
When the irradiation diameter is within a predetermined range, it is determined that the relative distance is a distance capable of securing the focal depth of the processing laser beam,
The laser processing apparatus according to claim 1, wherein when the irradiation diameter is out of the predetermined range, the relative distance is determined to be a distance at which a focal depth of the processing laser beam cannot be secured. The light collecting means includes
Partial transmission means arranged to transmit the measurement laser light collected by the condenser lens and reflect the processing laser light;
The laser processing apparatus according to claim 1, further comprising a reflection unit arranged to reflect the measurement laser beam transmitted through the partial transmission unit. The light collecting means includes
A first reflecting means arranged to reflect the measurement laser beam condensed by the condenser lens;
3. The laser processing apparatus according to claim 1, further comprising: a second reflecting unit arranged to reflect the processing laser beam condensed by the condenser lens. Irradiating a workpiece with a measuring laser through a condenser lens;
Detecting an irradiation diameter of the laser beam for measurement irradiated on the workpiece;
Determining whether the relative distance of the condensing lens with respect to the workpiece is a distance that can ensure the depth of focus of the processing laser light based on the detected irradiation diameter;
Moving the condenser lens relative to the workpiece based on the determination result; and
Irradiating the workpiece with a processing laser beam having a wavelength different from that of the measurement laser via the condenser lens. In the step of determining the relative distance of the condenser lens with respect to the workpiece,
When the irradiation diameter is within a predetermined range, it is determined that the relative distance is a distance that can ensure the depth of focus of the processing laser beam;
The laser processing method according to claim 5, wherein when the irradiation diameter is out of a predetermined range, the relative distance is determined to be a distance at which a focal depth of the processing laser beam cannot be secured.

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