JP2014223672A - Method of and device for laser-processing rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser-processing method and device capable of highly accurately measuring and correcting the axis deflection of a processing object to improve processing accuracy.SOLUTION: An object w to be processed is rotated before processing the object w. A laser beam L2 for measuring is arranged and irradiated so that the irradiation direction of the laser beam deviates from the rotation center C of the object w, and by making the laser beam reflect on the surface of the object w, the change of reflected light R2 is measured. Thereby, the magnitude of an axis deflection caused by axis deviation of the axial center O of the object w from the rotation center C is calculated, and the irradiation position of a laser beam L1 for processing is adjusted on the basis of the above calculation value.

Description

  The present invention relates to a laser processing method and a processing apparatus for forming or polishing a surface of a rotating body.

In laser processing (laser processing of a rotating body) in which a cylindrical or cylindrical workpiece is rotated around its central axis and laser light is shifted from the central axis (laser processing of a rotating body), the surface of the workpiece is processed along with the progress of processing. Since the incident angle of the laser beam changes, the processing removal amount per unit time changes. Therefore, it is difficult to estimate the required processing time from the volume to be processed and removed, and it is necessary to determine the end of processing by another method.
As a conventional method for determining the end of processing, for example, Patent Document 1 proposes a method of measuring a dimensional shape with an image immediately after processing and confirming whether the processed shape is obtained.
Japanese Patent Application Laid-Open No. H10-228561 describes a method for determining termination based on the intensity of emitted light during laser processing.

JP 07-116873 A Japanese Patent Application Laid-Open No. 07-124766

The method of Patent Document 1 has a problem that it takes time for processing because confirmation and rework of the form are repeated. In the method of Patent Document 2, since the light emission intensity of the laser light irradiation unit is affected by fluctuations in the internal composition of the workpiece, there is a problem that it is difficult to accurately associate the light emission intensity with the current processing amount.
Further, in the laser processing of such a rotating body, it is assumed that the processing object is rotated around the axis center of the processing object at the time of processing, but when chucking one end of the processing object to the rotating machine The slight deviation between the center of rotation and the axis of the workpiece may cause shaft runout during machining, leading to a reduction in machining accuracy. For this reason, when performing precision machining, it is necessary to remove the influence of the shaft runout caused by the axis deviation when chucking the workpiece.

  The present invention has been made in view of such circumstances, and provides a laser processing method and a processing apparatus capable of measuring and correcting axial runout of a processing object with high accuracy and improving processing accuracy. For the purpose.

  The present invention is a laser processing method for processing a processing object by irradiating a processing laser beam while holding and rotating the processing object, and before processing the processing object, the processing object The measurement laser beam is irradiated so that the irradiation direction is shifted with respect to the rotation center of the object to be processed, and reflected by the surface of the object to be processed. Measuring the amount of axial runout caused by the axial deviation between the axis of the workpiece and the center of rotation, and adjusting the irradiation position of the processing laser light based on the calculated value It is characterized by.

When the measurement laser beam is irradiated while rotating the workpiece, the measurement laser beam is reflected on the surface of the workpiece. Since the irradiation direction of the measurement laser beam is shifted with respect to the rotation center of the workpiece, the reflected light is reflected by the outer peripheral surface of the workpiece and irradiated in a direction different from the irradiation direction. . At this time, if the axis of the workpiece matches the center of rotation, the tilt of the irradiation surface irradiated with the measurement laser beam is constant even when the workpiece is rotated. The traveling direction is irradiated in a certain direction without changing.
However, when the axis of the workpiece and the center of rotation are misaligned, the tilt of the irradiated surface of the workpiece passing through the measurement laser beam irradiation position changes with rotation, and the reflected light advances. The direction will also change.
Thus, the magnitude of the axial deflection of the workpiece can be calculated from the movement of the reflected light at the irradiation position of the measurement laser beam accompanying the rotation of the workpiece. Then, the irradiation position of the laser beam for processing is tracked with the rotation of the processing object based on the calculated value, so that the axial deviation that occurs when the processing object is attached can be corrected, and the influence of the axial run-out can be eliminated. Accurate machining can be performed.

  In the laser processing method of the present invention, when the coordinates composed of the z-axis parallel to the irradiation direction and the y-axis orthogonal thereto are set with the rotation center as the origin, any reflected light of the measurement laser light Measuring a behavior in one direction, calculating a displacement in the z-axis direction and a displacement in the y-axis direction of the axial runout, and adjusting an irradiation position of the processing laser light based on the calculated value Features.

  In the laser processing method of the present invention, while holding and rotating the workpiece, the laser beam for processing is irradiated so that the irradiation direction is shifted from the rotation center of the workpiece, While processing the said process target object, the said process laser beam is reflected on the surface of the said process target object, and a process end point is determined by the change of the reflected light accompanying process progress, It is characterized by the above-mentioned.

When processing is performed by irradiating the processing laser light while rotating the processing target, the processing laser light is reflected on the surface of the processing target. Since this reflected light is arranged so that the irradiation direction of the processing laser light is deviated from the rotation center of the processing object, the beam diameter, the irradiation position, etc. at the irradiation position of the processing laser light as the processing proceeds The change is magnified and reflected in the reflected light. The processing end point can be determined from the change in the processing laser beam expanded by the reflected light, and high-precision determination can be performed. For example, the beam diameter on the surface of the workpiece and the change in the irradiation position in microns can be amplified in millimeters with the reflected light, and the processing end point can be determined with high accuracy from this amplified reflected light change. Can do.
Further, the direction and dimension of deviation between the irradiation direction of the processing laser beam and the rotation center may be different from those in the case of the measurement laser beam.

In the laser processing method of the present invention, the processing end point can be determined from a change in the position of the reflected light corresponding to a change in the processing position of the processing laser light.
Since the change in the position of the reflected light from the processing object is enlarged with respect to the change in the processing position of the processing laser light, the end point can be determined with high accuracy from the change in the position of the reflected light.

In the laser processing method of the present invention, the processing end point can be determined from a change in the diameter of the reflected light corresponding to the surface state of the processing object.
When polishing the surface of an object to be processed, the diameter of the reflected light of the laser beam for processing increases when the surface of the object to be processed is rough because the laser beam for processing diffuses, and decreases as the surface becomes smoother. Become. The end point of the surface polishing of the workpiece can be determined from the change in the diameter of the reflected light.

In the processing method of the present invention, the processing end point can be determined from a change in the vibration of reflected light corresponding to a local change in the radial dimension of the workpiece.
When local protrusions or the like are present on the surface of the processing object, the reflected light is vibrated by changing the reflection direction of the processing laser light due to the protrusions. The width of this vibration is reduced by the reduction of the protrusion as the processing proceeds. Therefore, when the decrease in the amplitude of the reflected light reaches the reference value, it can be determined that the processing end point.

In the laser processing method of the present invention, the measurement laser light or reflected light of the processing laser light may be projected onto a screen, and a change in the reflected light may be detected from the projected light.
By projecting the behavior of the reflected light of the laser beam for measurement or processing onto the screen, it is possible to easily and accurately determine the presence or absence of axial deflection of the processing target and the processing end point during processing by visual observation or the like.

  The laser processing apparatus of the present invention irradiates the workpiece with a workpiece holding means that holds and rotates the workpiece so that the laser beam for measurement is arranged with the irradiation direction shifted from the rotation center. Measured laser beam irradiation means and a calculated value by detecting an axial deviation between the axis of the workpiece and the rotation center based on a change in reflected light of the measurement laser beam reflected on the surface of the workpiece. A processing laser irradiation unit for processing the processing object based on the calculated value, and a processing end point by a change in reflected light of the processing laser light reflected on the surface of the processing object. It has an end point determination means that can be determined.

  According to the present invention, since the calculation and correction of the axial runout of the rotating workpiece can be performed with high accuracy, the machining accuracy can be improved.

It is a whole lineblock diagram showing the laser processing device concerning the present invention. It is a perspective view which shows typically the state which projects the reflected light of the processing laser beam irradiated to the process target object on the screen. It is a perspective view which shows typically the state which projects the reflected light of the laser beam for a measurement irradiated to the workpiece on the screen. It is a schematic diagram explaining the relationship between the axial deflection angle of a workpiece, and the reflected light of the measurement laser beam which detects axial deflection. It is a schematic diagram explaining the axial runout which arises by the axial shift of the axial center of a workpiece, and the rotation center. It is a schematic diagram explaining the relationship between the processing laser beam which processes the outer diameter of a process target object, and its reflected light. It is a schematic diagram explaining the relationship between the processing laser beam which grind | polishes the surface of a process target object, and its reflected light. It is a schematic diagram explaining the reflection state of the processing laser beam on the surface of the workpiece. It is a graph which shows the relationship between the processing time in grinding | polishing, and the change of the diameter of projection light. It is a schematic diagram explaining the reflective state of the laser beam for a process in case a processus | protrusion exists in the process target object surface.

Hereinafter, an embodiment of a laser processing method and a laser processing apparatus according to the present invention will be described with reference to the drawings.
First, an embodiment of a laser processing apparatus will be described. As shown in FIG. 1, the laser processing apparatus 1 according to this embodiment is an apparatus that performs processing by irradiating a processing object w with a processing laser beam L1. The laser processing apparatus 1 includes a laser irradiation unit 2 that irradiates the processing object w with the processing laser light L1 and the measurement laser L2, and rotates and moves in the x, y, and z axis directions while holding the processing object w. A workpiece holding means 3 having a possible stage, an end point determining means 4 (see FIG. 2) capable of determining a processing end point by a change in reflected light R1 of the processing laser beam L1 reflected by the surface of the workpiece w, and processing Correction means 5 for calculating a correction value by detecting an axial deviation between the axis of the workpiece w and the center of rotation based on a change in the reflected light R2 of the measurement laser beam L2 reflected by the surface of the workpiece w (FIG. 3). And control means 6 comprising a computer for controlling them.

The laser irradiation means 2 includes, for example, a laser light source 11 that oscillates laser light at a constant repetition frequency, a beam adjustment unit 12 that adjusts the spread of the laser light, a galvano scanner 13 that scans the irradiated laser light, and laser light. Are provided in a spot shape, and a plurality of mirrors m1 and m2 that bend the optical path.
As the laser light source 11, a light source capable of irradiating laser light with a wavelength of 190 nm to 1100 nm can be used. For example, in this embodiment, a laser light source that can oscillate and emit laser light with a wavelength of 355 nm is used. In the present embodiment, the energy density of the laser beam is adjusted by adjusting the output of the laser light source 11, and the processing laser beam L1 and the measuring laser beam L2 having different energy densities are irradiated. . The measurement laser beam L2 is set to an energy density lower than the processing threshold value of the processing object w and lower than the processing laser beam L1.
Note that a laser light source for irradiating the processing laser light L1 and a laser light source for irradiating the measuring laser light L2 may be provided separately.

  The work holding means 3 includes a chuck 21 that grips the workpiece w, a rotating mechanism 22 that rotates the chuck 21, and a stage 23x that is mounted with the rotating mechanism 22 and can move in the x, y, and z axis directions. 23z. Specifically, an x-axis stage unit 23x that can move in the x direction parallel to the horizontal plane and a y-axis stage that is provided below the x-axis stage unit 23x and is perpendicular to the x direction and parallel to the horizontal plane The configuration includes a possible y-axis stage unit 23y and a z-axis stage unit 23z that is provided below the y-axis stage unit 23y and is movable in a direction perpendicular to the horizontal plane.

Further, the laser processing apparatus 1 is provided with a light receiving means 31 capable of receiving both the reflected light R1 of the processing laser light L1 reflected by the surface of the workpiece w and the reflected light R2 of the measurement laser light L2. Then, as shown in FIG. 3, the correcting means 5 has an axis generated by the axial deviation between the axis O of the workpiece w and the rotation center C from the light receiving means 31 and the reflected light R2 received by the light receiving means 31. It is comprised from the calculation part 37 which calculates the magnitude | size of shake. Further, as shown in FIG. 2, the end point determination means 4 receives the reflected light R1 of the processing laser light L1 reflected from the surface of the workpiece w by the light receiving means 31, and determines the processing end point from the reflected light R1. It is comprised by the determination part 32 which consists of a computer to do.
As shown in FIGS. 2 and 3, in the present embodiment, the light receiving means 31 projects a screen 33 that projects the reflected light R1 or R2, and the projection light S1 and S2 of the reflected light R1 and R2 projected on the screen 33. It is comprised from the imaging means 34 which observes a behavior. In the illustrated example, the surface of the screen 33 is provided along the vertical direction (z-axis direction). However, the screen 33 may not necessarily be in the vertical direction as long as the reflected light R1 and R2 can be projected. Also, a posture inclined with respect to the vertical direction is possible, and an arcuate surface shape or the like may be used in addition to the planar shape. In this embodiment, a transmissive screen is used.

The imaging means 34 is provided with a moving mechanism 36 so that an imaging device 35 such as a CCD camera is disposed behind the transmissive screen 33 and the movement of the projection light S1 and S2 on the screen 33 can be tracked. In the case of this embodiment, the moving mechanism 36 is configured to move the imaging device 35 up and down on the rail 36a along the vertical direction because the projection lights S1 and S2 move in the vertical direction.
When the screen is a reflection type, the image pickup means may be arranged in front of the front surface (reflection surface) of the screen.
The determination unit 32 stores the coordinates of the end point position on the screen 33 in advance, and determines that it is the processing end point when the projection light S1 reaches the end point position on the screen 33 as described later. The determination unit 32 is provided in the control unit 6 as shown in FIG.

Next, a method for processing the workpiece w using the laser processing apparatus 1 will be described.
First, the workpiece w is fixed to the chuck 21 of the workpiece holding means 3. Then, before the machining of the workpiece w is started, the magnitude of the axial runout of the workpiece w caused by the axial deviation between the axis O of the workpiece w and the rotation center C of the workpiece holding means 3 is calculated.
The calculation of the magnitude of the axial deflection is performed by irradiating the processing object w with the measuring laser beam L2 at a fixed point and rotating the processing object w by the rotation mechanism 22 while reflecting the reflected light R2 reflected on the surface of the processing object w. This is done by measuring the projection light S2 on the screen 33. Further, the coordinates of the z axis parallel to the irradiation direction of the measurement laser beam L2 and the y axis orthogonal thereto are set with the rotation center C of the workpiece w as the origin, and the reflected light of the measurement laser beam L2 By measuring the behavior of R2 in the z-axis direction, the displacement of the axial runout in the z-axis direction and the displacement in the y-axis direction are calculated.
The measurement laser beam L2 is irradiated at a fixed point to a position shifted by a distance a in the horizontal direction (y-axis direction) with respect to the rotation center C. Then, the measurement laser beam L2 is reflected on the surface of the workpiece w, and the reflected light R2 is projected onto the screen 33 of the light receiving means 31 arranged to receive the reflected light R2.

When the axis O and the rotation center C of the workpiece w coincide with each other, the tilt of the irradiation surface of the workpiece w irradiated with the measurement laser light L2 is constant even when the workpiece w rotates. Therefore, the traveling direction of the reflected light R2 is irradiated in a certain direction without changing.
On the other hand, when the axis O and the rotation center C of the workpiece w are shifted, the inclination of the irradiation surface of the workpiece w passing through the irradiation position of the measurement laser beam L2 changes with rotation. The traveling direction of the reflected light R2 changes. Therefore, the projection position of the projection light S2 on the screen 33 changes with the rotation of the workpiece w, and the axis deviation between the axis O and the rotation center C of the workpiece w changes from the changed projection position of the projection light S2. The magnitude of the generated shaft runout can be calculated. And based on the calculated value, the correction value at the time of processing of the processing object w is calculated.

The correction value calculation method will be described with reference to FIGS. 4 and 5. FIG.
FIG. 5 shows a relationship between the axis O of the workpiece w generated when the cylindrical workpiece w is attached to the chuck 21 and the rotation center C of the workpiece w rotated by the chuck 21.
4 and 5, the measurement laser beam L2 has a constant value on the y coordinate (horizontal distance from the rotation center C of the workpiece w) of the optical axis (using the same symbol L2 as the measurement laser beam L2) L2. While maintaining a, the workpiece w is irradiated along the vertical direction (z-axis direction). Moreover, the screen 33 is arrange | positioned perpendicularly | vertically, for example in the position of the distance H from the rotation center C of the workpiece w.

When the axial wobbling of the workpiece w occurs, as shown in FIG. 5, the displacement (y coordinate) Δy _xθ and the displacement (z coordinate) in the y-axis direction of the axis O of the workpiece w ) Δz _xθ changes in circular motion, and therefore the magnitude R _x of the axial _wobbling of the workpiece w can be obtained from the amount of change in the z coordinate of the projection light S2. Then, the axis deviation caused when the workpiece w is attached to the workpiece holding means 3 by causing the irradiation position of the machining laser beam L1 to follow the rotation of the workpiece w based on the magnitude _Rx of the shaft runout. Can be corrected, and the influence of shaft runout during machining can be removed.
The y coordinate Δy _xθ and the z coordinate Δz _xθ of the correction value are _obtained by the following relational expression and the drawing of FIG.

In the above equation, “θ” and “x” are used as subscripts for each variable, which indicates that these variables are values that change according to the axial deflection angle θ or the position of the x coordinate. . From the above equation, the y coordinate Δy _xθ and the z coordinate Δz _xθ of the axis O of the workpiece w can be expressed by a relational expression between the axial deflection angle θ and the z coordinate (z _xθ ) of the projection light S2. .
For example, when the workpiece w rotates at an angular velocity ω and an initial phase θ ₀ , the y-coordinate Δy _xθ and the z-coordinate Δz _xθ of the axis O of the workpiece w over time t have the following relationship: It can be obtained by an expression.

By using the above equation, it is possible to calculate the size R _x from the measurement value of the z coordinate of the projected light S2, axial deflection in the x-coordinate of the position where the measuring laser light L2 is irradiated. Further, the z coordinate of the projection light S2 on the screen 33 changes with the rotation of the processing object w. From the amount of change of the z coordinate of the projection light S2 at this time, the y coordinate Δy _xθ of the processing object w and The z coordinate Δz _xθ can be obtained. Based on these calculated values, the processing object w is rotated by operating the galvano scanner 13 and the stage portions 23x to 23z to follow the irradiation position of the processing laser light L1 as the processing object w rotates. Axial misalignment that occurs when mounting to the machine can be corrected.

Next, a description will be given of a case where form processing is performed, such as processing for reducing the outer diameter of the workpiece w.
The processing laser light L1 and the stage portions 23x to 23z are controlled to irradiate the processing object w with the processing laser light L1, and the rotating mechanism 22 rotates the processing object w to a desired outer diameter. At this time, the irradiation position of the processing object w or the processing laser beam L1 is adjusted based on the calculated value of the axial deflection acquired in advance, so that the axis O of the processing object w matches the rotation center axis C. The workpiece w is processed in the same manner as the state. For this reason, it is possible to remove the influence of the shaft runout and perform high-precision machining on the workpiece w.
Hereinafter, in order to simply explain the shape processing of the workpiece w, the description will be made assuming that the axis O of the workpiece w and the rotation center axis C coincide with each other.

The processing laser beam L1 is irradiated to a position shifted in the horizontal direction (y-axis direction) with respect to the rotation center axis C of the workpiece w. A part of the processing laser beam L1 is reflected by the surface of the processing target object w when processing the processing target object w. The screen 33 of the light receiving means 31 is disposed so as to receive the reflected light R1, and the reflected light R1 is projected onto the screen 33. The workpiece w has a diameter that decreases with the progress of processing by the processing laser beam L1, and the position of the surface changes in accordance with the reduction of the diameter. For this reason, the processing laser beam L1 is incident on the workpiece w because the reflection position of the surface of the workpiece w changes in the z-axis direction and the radius of curvature of the surface decreases as the machining progresses. The angle (angle formed with the normal to the workpiece surface) also gradually increases. Corresponding to the change in the reflection position and the incident angle, the spread of the diameter and the reflection direction of the reflected light R1 change, and the size and the projection position of the projection light S1 on the screen 33 also change.
In the present invention, the end of processing is determined from the movement state of the projection light S1 of the reflected light R1.

A specific method for determining the end of machining during this form machining will be described with reference to FIG.
FIG. 6 shows a processing method for correcting the outer diameter of the cylindrical workpiece w from the radius r ₀ to r ₁ . In the case of this processing, the end of processing is determined not by the change in the spread of the diameter of the processing laser beam but by the change in the position of the center (optical axis) of the processing laser beam on the surface of the processing target in the z-axis direction.
The optical axis of the processing laser beam (using the same sign as the processing laser beam) L1 is maintained in the y-coordinate (horizontal distance from the center of rotation of the processing target w) at a constant value a in a direction perpendicular to the processing target w ( The processing laser light L1 is irradiated along the z-axis direction). Further, the screen 33 is arranged vertically, for example, at a position at a distance H from the rotation center C of the workpiece w.

With the progress of machining, reflected light R1 from the workpiece w, the center is moved to the R ₁ from R ₀ in FIG. 6, the center of the projected light on the screen 33 moves from the initial position z ₀ to -z direction . The center of the projection light, may be determined when it reaches z ₁ is the value of the corresponding z coordinate when a radius r ₁ is a machining end point of the workpiece w processing and end.
The coordinate z ₁ of this processing end position is obtained by the following relational expression.

n = 0 indicates the initial processing, and n = 1 indicates the end of processing.
According to the above equation, for example, when the initial values are r ₀ = 50 mm, a = 38 mm, and L = 300 mm, z ₀ ≈−8.7 mm. If 100 μm is processed in the radial direction and r ₁ = 49.9 mm, z ₁ ≈−10.1 mm, the difference Δz between z ₀ and z ₁ is about 1.4 mm, and the amount of movement of the projection light is the workpiece w It can be seen that the processing amount on the surface is greatly enlarged. Note that Δz can be further increased by changing the distance H and the tilt angle of the screen with respect to the z-axis.

  Thus, according to this method, the irradiation direction of the processing laser beam L1 with the progress of processing is set by disposing the irradiation direction of the processing laser beam L1 with respect to the rotation center C of the processing target w. The change in position is magnified and reflected in the reflected light, and the processing end point can be easily determined from the change in position of the projection light on the screen 33, so that highly accurate determination can be performed.

Next, the processing end determination when the surface of the workpiece w is polished will be described with reference to FIGS.
In this polishing process, changes such as the size of the projection light S1 can be used as a criterion for determining the end of the process. FIG. 7 schematically shows the relationship between the surface roughness of the workpiece w and the size of the projection light S1, but is sufficiently smaller than the spot diameter of the processing laser beam L1 on the surface of the workpiece w. When there is unevenness, scattering due to the unevenness occurs, so that the diameter of the projection light S1 becomes larger than when reflected by a smooth surface. Since the workpiece w is smoothed as the laser processing proceeds, the diameter of the projection light S1 decreases. As shown in FIG. 8 in an enlarged manner, the reflected light of the processing laser beam L1 spreads as shown by the solid line arrow due to irregular reflection in the initial processing state where the surface has large irregularities, so that the projection is performed as described above. On the other hand, the diameter of the light increases, and on the surface of the workpiece w smoothed at the end of the processing, the spread of the reflected light decreases as shown by the two-dot chain arrow in FIG. Becomes smaller.
FIG. 9 shows the change in the diameter of the projection light in a graph. The time when the diameter of the projection light reaches a predetermined reference value may be regarded as the end of processing.

  In addition, when the size of the unevenness on the surface of the workpiece w is larger than the spot diameter of the laser beam L1 for machining and the radial dimension of the workpiece w changes locally, Since the projection light moves so as to vibrate irregularly due to the unevenness as it rotates, the amplitude of the vibration may be used as a reference. FIG. 10 shows a case where a large protrusion P is present at a position where the processing laser beam L1 is irradiated on the surface of the processing target w. When the processing target w rotates, the reflected light of the processing laser light L1 is shown. The reflection direction of R1 moves so as to swing, for example, between a solid line arrow and a two-dot chain line arrow. As the projection P decreases with the progress of processing, the amplitude of the reflected light R1 also decreases. Therefore, when projected onto the screen, the amplitude of movement of the projection light decreases. What is necessary is just to determine with the completion | finish of a process, when this amplitude becomes below a predetermined reference value.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the light receiving means for receiving the reflected lights R1 and R2 may have a configuration other than the combination of the screen 33 and the imaging means 34. For example, at the time of form processing, a configuration may be adopted in which a plurality of photoelectric conversion elements are arranged on the moving path of the reflected light R1, and the processing end point is determined when the photoelectric conversion element corresponding to the processing end position is received. In the case of surface polishing, the reflected light is received by a plurality of photoelectric conversion elements, and the number of photoelectric conversion elements that can be received decreases as the diameter decreases. What is necessary is just to determine with an end. In addition, even when there are large protrusions on the surface of the workpiece, a plurality of photoelectric conversion elements are arranged along the vibration direction of the reflected light, and the number of photoelectric conversion elements received within the vibration range of the reflected light is reduced. Thus, the processing end may be determined. In these cases, not the projection light but the reflected light is directly received by the photoelectric conversion element.
In the present embodiment, the measurement laser beam and the processing laser beam have the same direction and size of deviation between the irradiation direction of the laser beam and the rotation center, but they may be different.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2 Laser irradiation means 3 Work holding means 4 End point determination means 5 Correction means 6 Control means 11 Laser light source 12 Beam adjustment part 13 Galvano scanner 14 Condensing lens 21 Chuck 22 Rotating mechanism 23x X axis stage 23y Y axis stage 23z z-axis stage 31 Light receiving means 32 Judging part 33 Screen 34 Imaging means 35 Imaging device 36 Moving mechanism 36a Rail 37 Calculation part C Center of rotation O Center axis L1, L2 of processing object Laser light R1, R2 Reflected light S1, S2 Projected light w Work object m1, m2 Mirror

Claims (8)

  A laser processing method for processing a processing target by irradiating a processing laser beam while holding and rotating the processing target, wherein the processing target is rotated before processing the processing target. Irradiating the measurement laser beam so that the irradiation direction is shifted with respect to the rotation center of the object to be processed, reflecting the laser beam on the surface of the object to be processed, and measuring the change in the reflected light. To calculate the magnitude of axial runout caused by the axial deviation between the axis of the workpiece and the center of rotation, and adjust the irradiation position of the processing laser beam based on the calculated value Laser processing method.   When a coordinate consisting of a z-axis parallel to the irradiation direction and a y-axis orthogonal thereto is set with the rotation center as the origin, the behavior of the reflected light of the laser beam for measurement is measured in any one direction The displacement in the z-axis direction and the displacement in the y-axis direction of the axial runout are calculated, and the irradiation position of the processing laser light is adjusted based on the calculated values. Laser processing method.   While processing and holding the processing object, the processing laser beam is irradiated so that the irradiation direction of the processing laser beam is shifted from the rotation center of the processing object. The laser processing method according to claim 1, wherein the processing laser light is reflected on a surface of the processing object, and a processing end point is determined based on a change in reflected light as the processing progresses.   4. The laser processing method according to claim 3, wherein the processing end point is determined from a change in the position of the reflected light corresponding to a change in a processing position of the processing laser light.   4. The laser processing method according to claim 3, wherein the processing end point is determined from a change in the diameter of the reflected light corresponding to a surface state of the processing object.   The laser processing method according to claim 3, wherein the processing end point is determined from a change in vibration of reflected light corresponding to a local change in a radial dimension of the processing object.   The reflected light of the laser beam for measurement or the laser beam for processing is projected on a screen, and the change of the reflected light is detected from the projected light. Laser processing method.   A workpiece holding means that holds and rotates the workpiece, and a measurement laser beam irradiating means that irradiates the workpiece with the measurement laser beam so that the irradiation direction is shifted from the rotation center; Correction means for detecting an axial misalignment between the axis of the workpiece and the center of rotation based on a change in reflected light of the measurement laser beam reflected on the surface of the workpiece, and calculating a calculated value thereof; A processing laser irradiation unit that processes the processing object based on the calculated value, and an end point determination unit that can determine a processing end point based on a change in reflected light of the processing laser beam reflected on the surface of the processing object. The laser processing apparatus characterized by the above-mentioned.

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