JP2019141877A - Laser processing device - Google Patents

Abstract

To provide a laser processing device that can properly measure surface roughness of an object to be processed.SOLUTION: A laser processing device 1 comprises a support base 81a, a laser light irradiation part 10, a light sensor head 121, a light power meter 122 and a surface roughness deriving instrument 123. The laser light irradiation part 10 emits laser light for processing and laser light LB2 for measuring roughness whose light energy is smaller than light energy of the laser light for processing to a surface to be processed (a flat surface W2 to be processed) of an object to be processed supported on the support base 81a. The light power meter 122 derives intensity of scattering light from the flat surface W2 to be processed, on the basis of a result of light-receiving by the light sensor head 121. The surface roughness deriving instrument 123 measures roughness of the flat surface W2 to be processed. The light sensor head 121, provided at a position shifted from a light shaft K of reflected light to be propagated concentrically with the laser light for processing reflected on the surface to be processed, receives laser light LB2 for measuring roughness reflected or scattered on the flat surface W2 to be processed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser processing apparatus.

  Conventionally, as a laser processing apparatus, for example, Patent Document 1 discloses a laser oscillator that irradiates a laser beam for roughness measurement and a laser beam for processing, and a laser beam for roughness measurement that irradiates the surface of a workpiece. A machined surface finish processing apparatus is disclosed that includes a surface roughness measuring device that measures the roughness of the surface of the workpiece by the reflected light. This machined surface finishing machine, for example, measures the surface roughness of the workpiece with a laser beam for roughness measurement, and then increases the output of the laser oscillator to finish the surface of the workpiece with the laser beam for machining. Process.

JP 59-87993 A

  By the way, in the machined surface finishing apparatus described in Patent Document 1 described above, for example, powerful reflected light of a laser beam for machining may adversely affect the surface roughness measuring instrument.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a laser processing apparatus capable of appropriately measuring the roughness of the surface of a workpiece.

  In order to solve the above-described problems and achieve the object, a laser processing apparatus according to the present invention includes a support base that supports a workpiece having irregularities on a processing surface, and the workpiece that is supported by the support base. A laser beam irradiation unit that irradiates the processing surface of an object with a processing laser beam and a laser beam for roughness measurement whose light energy is smaller than that of the processing laser beam, and a light receiving unit that receives the light And a measuring unit capable of deriving at least one of reflected light intensity or scattered light intensity from the processing surface based on a light reception result by the light receiving unit and deriving roughness of the processing surface, The light receiving unit is provided at a position shifted from the optical axis of the reflected light that propagates coaxially with the laser beam for processing reflected by the processing surface, and is used for measuring the roughness reflected or scattered by the processing surface. It is characterized by receiving laser light.

  In the laser processing apparatus, the laser beam irradiation unit is a position where an emission position for emitting the processing laser beam and an emission position for emitting the roughness measuring laser beam are different, and the laser for processing It is preferable that the optical axis of the light and the optical axis of the laser beam for roughness measurement intersect.

  In the laser processing apparatus, the laser beam irradiating unit has an emission position for emitting the machining laser beam and an emission position for emitting the roughness measuring laser beam, and the machining laser. The optical axis of the light and the optical axis of the laser beam for roughness measurement are preferably coaxial.

  The laser processing apparatus includes a control unit that controls the laser beam irradiation unit and the measurement unit, and the control unit satisfies a predetermined reference value for a roughness of the processing surface measured by the measurement unit. If not, it is preferable to flatten the processing surface by irradiating the processing surface with the laser light for processing by the laser light irradiation section.

  In the laser processing apparatus according to the present invention, since the light receiving unit is provided at a position shifted from the optical axis of the reflected light of the processing laser light reflected by the processing surface, the reflected light of the powerful laser light for processing is received. It can suppress that a part receives light, and can measure the roughness of the surface of a workpiece appropriately.

FIG. 1 is a schematic diagram illustrating a configuration example of a laser processing apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a configuration example of the laser processing apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a measurement example of the intensity of scattered light according to the first embodiment. FIG. 4 is a flowchart illustrating an operation example of the laser processing apparatus according to the first embodiment. FIG. 5 is a schematic diagram illustrating a configuration example of the laser processing apparatus according to the second embodiment. FIG. 6 is a diagram illustrating a measurement example of the intensity of reflected light according to the second embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment 1
A laser processing apparatus 1 according to the first embodiment will be described. The laser processing apparatus 1 irradiates the workpiece W with the processing laser beam LB1 and processes the workpiece W, and irradiates the workpiece W with the roughness measurement laser beam LB2. This is an apparatus for measuring the roughness of the surface of the workpiece W. Here, the workpiece W is formed of, for example, a metal material. The workpiece W is, for example, a layered product by a 3D printer, a metal workpiece on which a tool mark or the like is formed. In the following description, the laser beam LB1 for processing and the laser beam LB2 for roughness measurement are simply referred to as laser beam LB when it is not necessary to distinguish them. Hereinafter, the laser processing apparatus 1 will be described in detail.

  In the following description, the X direction (first direction), the Y direction (second direction), and the Z direction (third direction) are directions orthogonal to each other. The X direction and the Y direction are directions orthogonal to each other on a support surface 81b that supports a workpiece W to be described later. The Z direction is a direction orthogonal to the support surface 81b. The X direction and the Y direction are typically directions orthogonal to each other on the virtual plane when a plane orthogonal to the thickness direction of the workpiece W is a virtual plane, and the Z direction is a virtual plane. It is an orthogonal direction orthogonal to.

  For example, the laser processing apparatus 1 fixes the focus of the laser beam LB1 for processing and focuses the laser beam LB1 for processing on the processing surface W1 of the workpiece W to be processed. As shown in FIGS. 1 and 2, the laser processing apparatus 1 includes a laser beam irradiation unit 10, a shutter 20, an attenuator 30, a beam expander 40, a beam transmission optical system 50, an incident light optical system 60, The objective lens 70, the drive part 80, the lamp illumination 90, the camera 100, the gas supply apparatus 110, the measuring instrument 120 as a measurement part, the control part 130, and the support pillar 140 are provided.

The laser beam irradiation unit 10 is a laser beam oscillator that oscillates a pulsed output (laser beam LB) at a constant repetition frequency. The laser beam irradiation unit 10 is supported by a support column 140. The laser beam irradiation unit 10 is, for example, a master oscillator output amplifier (MOPA) using a variable pulse width light source as a seed light source. The pulse width variable light source irradiates, for example, a processing laser beam LB1 and a roughness measurement laser beam LB2. The laser beams LB1 and LB2 for processing and roughness measurement are, for example, collimated light that is collimated light. When the laser beam irradiation unit 10 uses MOPA, an example of output characteristics of the processing laser beam LB1 is as follows. That is, the operating wavelength of the processing laser beam LB1 is about 1030 nm ± 1 nm, the repetition frequency is about 5 kHz to 10 MHz, the pulse width is about 50 ps to 1 μs, and the output power is 10 W or more. The polarization is a straight line, the beam quality square (M ² ) is less than 1.2, and the roundness is more than 80%. The laser beam irradiation unit 10 outputs (emits) laser beams LB1 and LB2 for processing and roughness measurement to the shutter 20. The pulse width is the time interval between the rise and fall of the pulse at a point that is half the peak power of the laser beam LB. Since the laser beam irradiation unit 10 can change the pulse width by using MOPA, the laser beam irradiation unit 10 can cope with various types of processing and can suppress the processing cost.

  In the flattening process, the laser beam irradiation unit 10 uses a processing laser beam LB1 having a short pulse width of a picosecond order. The laser beam LB1 for processing has a higher peak value of laser intensity and a shorter pulse width than a laser beam LB2 for roughness measurement described later. The laser beam LB1 for processing has a light energy density at which the peak value of the laser intensity can obtain a processing depth corresponding to the maximum height (for example, a height exceeding 10 μm) of the convex portion of the processing surface W1. It is. The convex portion of the processing surface W1 is a portion protruding along the Z direction when the deepest portion (bottom of the concave portion) of the processing surface W1 is used as a reference position.

  The laser beam irradiation unit 10 uses the laser beam LB2 for measuring roughness of light energy density (light energy) smaller than the laser beam LB1 for processing in the roughness measurement of the processing flat surface (surface to be processed) W2. The laser beam LB2 for roughness measurement has, for example, a pulse width in the order of nanoseconds to microseconds. The laser beam LB2 for roughness measurement has a light energy density at which the peak value of the laser intensity is lower than that of the processing laser beam LB1, and the peak value of the laser intensity does not process the processed flat surface W2. In the laser beam irradiation unit 10, the emission position L for emitting the processing laser beam LB1 and the emission position M for emitting the roughness measurement laser beam LB2 are the same position. In the laser beam irradiation unit 10, for example, the emission positions L and M are located on an axis along the Z direction. In the laser beam irradiation unit 10, the optical axis P of the processing laser beam LB1 and the optical axis Q of the roughness measuring laser beam LB2 are coaxial. That is, when viewed from the Z direction, the laser beam irradiation unit 10 has the optical axis P of the processing laser beam LB1 overlapped with the optical axis Q of the roughness measuring laser beam LB2.

  The shutter 20 switches between transmission and blocking of the laser beam LB. The shutter 20 is installed between the laser beam irradiation unit 10 and the attenuator 30 and transmits or blocks the laser beam LB output from the laser beam irradiation unit 10. The shutter 20 outputs the transmitted laser beam LB to the attenuator 30.

  The attenuator 30 is an attenuator that adjusts the intensity of the laser beam LB. The attenuator 30 is installed between the shutter 20 and the beam expander 40, adjusts the intensity of the laser light LB output from the shutter 20, and outputs it to the beam expander 40.

  The beam expander 40 widens the beam diameter of the laser beam LB. The beam expander 40 is installed between the attenuator 30 and the beam transmission optical system 50, widens the beam diameter of the laser light LB output from the attenuator 30, and outputs it to the beam transmission optical system 50.

  The beam transmission optical system 50 is an optical system including a light guide mirror that guides the laser beam LB. The beam transmission optical system 50 is installed between the beam expander 40 and the epi-illumination optical system 60, guides the laser beam LB output from the beam expander 40, and outputs it to the epi-illumination optical system 60.

  The epi-illumination optical system 60 is an optical system including a direction change mirror that changes the direction in which the laser beam LB travels. The epi-illumination optical system 60 is installed between the beam transmission optical system 50 and the objective lens 70, changes the traveling direction of the laser beam LB output from the beam transmission optical system 50, and outputs the laser beam LB to the objective lens 70.

  The objective lens 70 collects the laser beam LB and irradiates the workpiece surface W1 of the workpiece W with the laser beam LB. The objective lens 70 is installed between the epi-illumination optical system 60 and the driving unit 80, condenses the laser light LB output from the epi-illumination optical system 60, and processes the workpiece W supported by the driving unit 80. The surface W1 is irradiated with the laser beam LB.

  The drive unit 80 holds the workpiece W and moves the workpiece W relative to the optical system including the objective lens 70 and the like. The drive unit 80 includes an XY axis drive unit 81 and a Z axis drive unit 82. The XY axis drive unit 81 includes a flat plate-shaped support base 81a that supports the workpiece W, a fixing unit (not shown), and an XY axis drive mechanism (not shown) configured by a ball screw or the like. The XY-axis drive unit 81 fixes the workpiece W to the support surface 81b of the support base 81a by the fixing unit, and the workpiece W to the optical system such as the objective lens 70 by the XY-axis drive mechanism in the X direction or Y direction. Move relative to the direction. The Z-axis drive unit 82 includes a Z-axis drive mechanism (not shown) configured by a ball screw or the like, and moves the workpiece W relative to the optical system such as the objective lens 70 in the Z direction by the Z-axis drive mechanism. .

  The lamp illumination 90 illuminates the workpiece W with illumination for imaging. The lamp illumination 90 is installed, for example, facing the support surface 81b of the drive unit 80, and illuminates the workpiece W supported by the support surface 81b.

  The camera 100 images the workpiece W. The camera 100 is installed to face the support surface 81b of the drive unit 80, and images the unevenness of the work surface W1 of the work W supported by the support surface 81b. The camera 100 outputs the captured image to the control unit 130.

  The gas supply device 110 supplies gas. The gas supply device 110 supplies, for example, an inert gas (for example, argon, nitrogen gas, etc.). The gas supply device 110 has a nozzle directed toward the workpiece W, and injects an inert gas from the nozzle toward the workpiece surface W1 of the workpiece W.

  The measuring instrument 120 measures the surface roughness of the workpiece W. The measuring instrument 120 includes, for example, an optical sensor head (light receiving unit) 121 having a light receiving surface 121a, an optical power meter 122, and a surface roughness deriving device 123. The optical sensor head 121 photoelectrically converts received light. The optical sensor head 121 receives, for example, scattered light scattered by the laser beam LB2 for roughness measurement irradiated on the processing flat surface W2, and photoelectrically converts the received scattered light. The optical sensor head 121 is arranged such that its light receiving surface 121a is diagonally opposed to the processing flat surface W2. The optical sensor head 121 is provided at a position shifted from the optical axis K of the reflected light propagating coaxially with the processing laser light LB1 reflected by the processing surface W1. In other words, the optical sensor head 121 is provided along the intersecting direction intersecting the optical axis K of the reflected light of the processing laser light LB1 reflected by the processing surface W1. In the optical sensor head 121, for example, the light receiving surface 121a is orthogonal to the intersecting direction. The optical sensor head 121 is connected to the optical power meter 122 and receives the scattered light of the laser beam LB2 for roughness measurement. Then, the optical sensor head 121 outputs a measurement signal (scattered light power) obtained by photoelectrically converting the received scattered light to the optical power meter 122. In addition, when the material vapor | steam of the to-be-processed object W produced by the planarization process contaminates the optical sensor head 121, the measuring device 120 attaches a cover to the optical sensor head 121 at the time of the planarization process. The optical sensor head 121 may guide the incident light to the optical sensor head 121 through an optical fiber having a large diameter end face, a bundle fiber in which a plurality of optical fibers are bundled, or the like.

  The optical power meter 122 derives scattered light power (scattered light intensity), and the surface roughness deriving device 123 derives surface roughness. The optical power meter 122 is connected to the optical sensor head 121 and derives the optical power of the scattered light based on the measurement signal output from the optical sensor head 121. Here, as shown in FIG. 3, the surface roughness deriving device 123 has a reference table showing the relationship between the scattered light power and the surface roughness with reference to the intensity of laser light irradiation for roughness measurement. In FIG. 3, the vertical axis represents the relative scattered light power (dB), and the horizontal axis represents the surface roughness Ra (nm). In FIG. 3, actual measurement data actually measured is represented by a solid line, and an approximate line of the actual measurement data is represented by a dotted line. The actual measurement data is data in which the relative scattered light power of the laser beam LB2 for roughness measurement irradiated on the surface of the sample of the workpiece W and the surface roughness of the sample are recorded in advance. The measured data tends to increase the surface roughness Ra as the scattered light power increases. The surface roughness deriving device 123 derives the surface roughness of the processing flat surface W2 based on the scattered light power of the reference table that matches the scattered light power of the measurement signal. The surface roughness deriving device 123 is connected to the control unit 130 and outputs the derived surface roughness of the processed flat surface W2 to the control unit 130.

  The control unit 130 controls the laser processing apparatus 1. The control unit 130 includes an electronic circuit mainly composed of a well-known microcomputer including a CPU, a ROM that constitutes a storage unit, a RAM, and an interface. The control unit 130 controls the optical system such as the laser beam irradiation unit 10 and the shutter 20 to adjust the output of the laser beam LB. The control unit 130 also controls the gas supply device 110 to adjust the flow rate of the inert gas. Further, the control unit 130 determines whether or not the roughness of the processed flat surface W2 is appropriate based on a predetermined roughness reference value.

  Next, an operation example of the laser processing apparatus 1 will be described with reference to FIG. In the laser processing apparatus 1, processing conditions are set in advance by an operator (step S1). Here, the processing conditions are, for example, the energy density of the laser beam LB, the overlap of spot diameters during scanning, the number of repeated irradiations, the processing time, and the like. These processing conditions are obtained in advance by experiments or the like based on the material of the workpiece W, the roughness of the unevenness of the processing surface W1, and the like.

  After the processing conditions are set, the laser processing apparatus 1 performs flattening processing (step S2). The laser processing apparatus 1 fixes the workpiece W supported on the support base 81a of the driving unit 80 to the driving unit 80, moves the workpiece W in the X direction or the Y direction by the XY axis driving unit 81, and further The workpiece W is moved in the Z direction by the Z-axis drive unit 82 to move the workpiece W to the machining start position. The laser processing apparatus 1 controls the gas supply device 110 to supply an inert gas to the workpiece W. And the laser processing apparatus 1 irradiates the convex part of the to-be-processed surface W1 with the laser beam LB1 for a process, imaging the to-be-processed surface W1 of the to-be-processed object W with the camera 100. FIG. The laser processing apparatus 1 moves the workpiece W in the X direction or the Y direction by the XY axis drive unit 81 in a state where the laser beam LB1 for processing is irradiated, so that the processing surface W1 is processed. While the laser beam LB1 is scanned, the convex portion of the processing surface W1 is processed. The laser processing apparatus 1 is, for example, an ablation process that flattens the convex portion of the processing surface W1 by instantaneously evaporating and scattering a portion irradiated with the processing laser light LB1, or processing laser light LB1. The processed flat surface W2 is formed by melting processing or the like for flattening the convex portion of the processing surface W1 by melting the portion irradiated with.

  Next, the laser processing apparatus 1 measures the roughness of the processing flat surface W2 (step S3). In the measurement of the roughness of the processing flat surface W2, the laser processing apparatus 1 controls the gas supply apparatus 110 and stops supplying the inert gas. Then, the laser processing apparatus 1 irradiates the processing flat surface W2 with the laser beam LB2 for roughness measurement while imaging the processing flat surface W2 with the camera 100. The laser processing apparatus 1 may set the workpiece W to a desired height by moving the workpiece W in the Z direction by the Z-axis drive unit 82, for example. The laser processing apparatus 1 moves the workpiece W in the X direction or the Y direction by the XY axis drive unit 81 in a state where the laser beam LB2 for roughness measurement is irradiated, so that the rough processing surface W2 is roughened. The laser beam LB2 for thickness measurement is scanned, and the scattered light power of the laser beam LB2 for roughness measurement is detected at a plurality of locations. Then, the laser processing apparatus 1 measures the roughness of the processing flat surface W2 based on the detected scattered light power. Note that the processed flat surface W2 has a nonuniform distribution of scattering angles with respect to roughness, and therefore the local scattered light power is not equal. For this reason, it is conceivable that the laser processing apparatus 1 uses an average value or the like of scattered light power.

  The laser processing apparatus 1 determines whether or not the roughness of the processing flat surface W2 is appropriate based on a predetermined roughness reference value. For example, the control unit 130 compares the roughness of the processed flat surface W2 with the reference value, and determines whether the roughness of the processed flat surface W2 is smaller than the reference value (step S4). When the roughness of the processed flat surface W2 is smaller than the reference value (step S4; Yes), the control unit 130 ends the flattening process of the workpiece W. When the roughness of the processing flat surface W2 is equal to or larger than the reference value (step S4; No), the control unit 130 returns to step S2 described above, and irradiates the processing flat surface W2 with the processing laser beam LB1. The surface W2 is flattened. In this case, the optical energy density of the processing laser beam LB1 is adjusted according to the roughness of the processing flat surface W2, that is, the size of the convex portion remaining on the processing flat surface W2.

  As described above, the laser processing apparatus 1 according to the first embodiment includes the support base 81a, the laser light irradiation unit 10, the optical sensor head 121, the optical power meter 122, and the surface roughness deriving device 123. The support table 81a supports the workpiece W having irregularities on the processing surface W1. The laser beam irradiation unit 10 has a light energy higher than that of the processing laser beam LB1 and the processing laser beam LB1 on the processing surface W1 (processing flat surface W2) of the workpiece W supported by the support table 81a. Is irradiated with a laser beam LB2 for roughness measurement. The optical power meter 122 can derive the scattered light intensity from the processed flat surface W <b> 2 based on the light reception result by the optical sensor head 121. The surface roughness deriving device 123 derives the roughness of the processed flat surface W2. The optical sensor head 121 is provided at a position shifted from the optical axis K of the reflected light propagating coaxially with the processing laser beam LB1 reflected by the processing surface W1, and is used for roughness measurement scattered on the processing flat surface W2. The laser beam LB2 is received.

  With this configuration, the laser processing apparatus 1 can perform the flattening processing of the processing surface W1 and the roughness measurement of the processing flat surface W2 with the same apparatus. Thereby, the laser processing apparatus 1 can improve workability because it is not necessary to move the workpiece W to a dedicated apparatus for roughness measurement. Moreover, the laser processing apparatus 1 can suppress the reflected light of the powerful processing laser beam LB1 from being received by the optical sensor head 121, and can suppress adverse effects (damage) on the optical sensor head 121. As a result, the laser processing apparatus 1 can appropriately measure the roughness of the surface of the workpiece W. Even when the surface roughness of the workpiece W is relatively large and the roughness of the surface of the workpiece W cannot be measured using reflected light, the laser processing apparatus 1 can detect the surface of the workpiece W due to scattered light. Roughness can be measured.

  In the laser processing apparatus 1, the laser beam irradiating unit 10 has the same emission position L for emitting the processing laser beam LB 1 and the emission position M for emitting the roughness measuring laser beam LB 2. The optical axis P of the laser beam LB1 and the optical axis Q of the laser beam LB2 for roughness measurement are coaxial. With this configuration, the laser processing apparatus 1 can prevent the reflected light of the powerful processing laser beam LB1 from being received by the optical sensor head 121, and can suppress damage to the optical sensor head 121. Then, the laser processing apparatus 1 can appropriately measure the roughness of the processed flat surface W2 based on the result of receiving the scattered light by the optical sensor head 121.

  The laser processing apparatus 1 includes a control unit 130 that controls the laser beam irradiation unit 10 and the surface roughness deriving device 123. When the roughness of the processing flat surface W2 derived by the surface roughness deriving device 123 does not satisfy a predetermined reference value, the control unit 130 causes the laser light irradiation unit 10 to apply the processing laser beam LB1 to the processing flat surface. The processed flat surface W2 is further flattened by irradiating W2. With this configuration, the laser processing apparatus 1 can improve the quality of planarization by performing additional processing. Moreover, the laser processing apparatus 1 can process locally based on the information of the position where the roughness of the processing flat surface W2 does not satisfy the reference value.

[Embodiment 2]
Next, a laser processing apparatus 1A according to Embodiment 2 will be described. The laser processing apparatus 1A according to the second embodiment is different from the first embodiment in that the roughness of the processed flat surface W2 is measured using reflected light. In addition, the same code | symbol is attached | subjected to the component equivalent to Embodiment 1, and the detailed description is abbreviate | omitted. As shown in FIG. 5, the laser processing apparatus 1 </ b> A includes a support column 140 </ b> A that movably supports the laser light irradiation unit 10. The support pillar 140A extends along the Z direction orthogonal to the support surface 81b. 140 A of support pillars are assembled | attached so that the elongate laser beam irradiation part 10 can rotate freely. The support pillar 140A supports, for example, a substantially central portion in the long side direction of the laser light irradiation unit 10, and allows the laser light irradiation unit 10 to rotate about the central portion and move in the horizontal direction (X direction). I support it. The laser light irradiation unit 10 is rotated about the central portion, whereby the direction of the laser light irradiation unit 10 with respect to the support surface 81b is changed. The laser light irradiation unit 10 extends, for example, along the Z direction in which the optical axis P of the laser light irradiation unit 10 is orthogonal to the support surface 81b by setting the direction of the laser light irradiation unit 10 to the processing position direction. Exists. The laser beam irradiation unit 10 can irradiate the processing laser beam LB1 perpendicularly to the processing surface W1. Further, the laser light irradiation unit 10 is set along the intersecting direction in which the optical axis Q of the laser light irradiation unit 10 intersects the Z direction by setting the direction of the laser light irradiation unit 10 to the roughness measurement position direction. Extend. The laser beam irradiation unit 10 can irradiate the laser beam LB2 for roughness measurement with an inclination with respect to the processing flat surface W2. Thus, the laser beam irradiation unit 10 is a position where the emission position L for emitting the processing laser beam LB1 and the emission position M for emitting the roughness measuring laser beam LB2 are different, and the processing laser beam. The optical axis P of LB1 and the optical axis Q of the laser beam LB2 for roughness measurement intersect. In the measuring instrument 120A, the light receiving surface 121a of the optical sensor head 121 is provided so that it can receive the reflected light of the laser beam LB2 for roughness measurement. The light receiving surface 121a is spaced apart from the support base 81a by a certain distance in order to suppress the reception of scattered light scattered by the roughness measuring laser light LB2. The measuring instrument 120A derives the roughness of the processed flat surface W2 based on the reflected light of the laser beam LB2 for roughness measurement irradiated to the processed flat surface W2 by the laser light irradiation unit 10. Here, the optical power meter 122 of the measuring instrument 120A can derive the reflected light power (reflected light intensity) from the processed flat surface W2. As shown in FIG. 6, the surface roughness deriving device 123 of the measuring instrument 120A has a reference table showing the relationship between the reflected light power and the surface roughness with reference to the intensity of laser light irradiation for roughness measurement. . In FIG. 6, the vertical axis represents the relative reflected light power (dB), and the horizontal axis represents the surface roughness Ra (nm). In FIG. 6, actual measurement data actually measured is represented by a solid line, and an approximate line of the actual measurement data is represented by a dotted line. The actual measurement data is data in which the relative reflected light power of the laser beam LB2 for roughness measurement irradiated on the surface of the sample of the workpiece W and the surface roughness of the sample are recorded in advance. The measured data tends to increase the surface roughness Ra as the reflected light power decreases. The surface roughness deriving device 123 derives the surface roughness of the processing flat surface W2 based on the reflected light power of the reference table that matches the reflected light power of the measurement signal. The surface roughness deriving device 123 is connected to the control unit 130 and outputs the derived surface roughness of the processed flat surface W2 to the control unit 130.

  As described above, in the laser processing apparatus 1A according to the second embodiment, the laser beam irradiation unit 10 outputs the emission position L for emitting the processing laser beam LB1 and the emission position M for emitting the roughness measurement laser beam LB2. And the optical axis P of the laser beam LB1 for processing intersects with the optical axis Q of the laser beam LB2 for roughness measurement. With this configuration, the laser processing apparatus 1 </ b> A can prevent the reflected light of the powerful processing laser beam LB <b> 1 from being received by the optical sensor head 121, and can suppress damage to the optical sensor head 121. Then, the laser processing apparatus 1A can appropriately measure the roughness of the processing flat surface W2 based on the light reception result of the reflected light by the optical sensor head 121.

[Modification]
Next, a modification of the embodiment will be described. Although the laser beam irradiation part 10 demonstrated the example which irradiates the laser beams LB1 and LB2 for processing and roughness measurement with the same light source, it is not limited to this. The laser beam irradiation unit 10 may irradiate the laser beam LB1 for processing and the laser beam LB2 for roughness measurement using different laser light sources. The laser beam LB2 for roughness measurement may be irradiated using, for example, a He—Ne laser. At this time, by providing the optical sensor head 121 with a filter that cuts off the wavelength of the processing laser, it is possible to measure the roughness simultaneously with the processing.

  Although 1 A of laser processing apparatuses demonstrated the example which changes the optical axes P and Q of the said laser beam irradiation part 10 with respect to the support surface 81b by rotating the laser beam irradiation part 10, it is not limited to this. For example, the laser processing apparatus 1A may change the optical axes P and Q of the laser light irradiation unit 10 with respect to the support surface 81b by rotating the support base 81a with respect to the laser light irradiation unit 10 having a fixed position. Good. In this case, it is necessary to use the center of rotation as a processing point in order to measure the processing portion. Further, the laser processing apparatus 1A changes the optical axes P and Q of the laser light irradiation unit 10 relative to the support surface 81b by relatively rotating (moving) both the laser light irradiation unit 10 and the support base 81a. May be.

  The laser processing apparatus 1 has been described with respect to the example in which the position of the optical system including the objective lens 70 and the like is fixed and the workpiece W is processed by being relatively moved in the X direction, the Y direction, or the Z direction. It is not limited. For example, the laser processing apparatus 1 fixes the position of the workpiece W and relatively moves the optical system including the objective lens 70 in the X direction, the Y direction, or the Z direction to process the workpiece W. A scanner or the like may be used.

  Although the laser light irradiation unit 10 has been described as an example of a main oscillator output amplifier (MOPA) using a pulse width variable light source as a seed light source, the present invention is not limited to this, and another pulse width variable light source may be used.

  The laser beams LB1 and LB2 for processing and roughness measurement may be continuous wave laser beams (CW (Continuous Wave) laser beams) that continuously oscillate a constant output.

  The measuring instruments 120 and 120A can also detect a peculiar reflected light or scattered light pattern in the case of a roughness property such that a tool mark remains on the workpiece W.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 10 Laser beam irradiation part 81a Support stand 121 Optical sensor head (light-receiving part)
122 Optical power meter (measurement unit)
130 Control part LB1 Laser beam LB2 for processing Laser beam W for roughness measurement Workpiece W1 Work surface W2 Work flat surface (work surface)
L, M Emission position K Optical axis of reflected laser beam P for processing Optical axis Q of laser beam for processing Optical axis of laser beam for roughness measurement

Claims (4)

A support base for supporting a workpiece having irregularities on the workpiece surface;
Laser light for irradiating the processing surface of the workpiece supported by the support table with laser light for processing and laser light for roughness measurement whose light energy is smaller than that of the laser light for processing An irradiation unit;
A light receiving portion for receiving light;
A measurement unit capable of deriving at least one of reflected light intensity or scattered light intensity from the processing surface based on a light reception result by the light receiving unit, and deriving roughness of the processing surface,
The light receiving unit is provided at a position shifted from an optical axis of reflected light that is transmitted coaxially with the laser beam for processing reflected on the processing surface, and is used for measuring the roughness reflected or scattered on the processing surface. The laser processing apparatus characterized by receiving the laser beam.   The laser beam irradiation unit is a position where an emission position for emitting the processing laser beam and an emission position for emitting the roughness measuring laser beam are different from each other, and the optical axis of the processing laser beam and the laser beam The laser processing apparatus according to claim 1, wherein the optical axis of the laser beam for roughness measurement intersects.   In the laser beam irradiation unit, an emission position for emitting the laser beam for processing and an emission position for emitting the laser beam for roughness measurement are the same position, and the optical axis of the laser beam for processing and the The laser processing apparatus according to claim 1, wherein the optical axis of the laser beam for roughness measurement is coaxial. A control unit for controlling the laser beam irradiation unit and the measurement unit;
The control unit irradiates the processing surface with the laser light for processing by the laser light irradiation unit when the roughness of the processing surface measured by the measurement unit does not satisfy a predetermined reference value. The laser processing apparatus according to claim 1, wherein the processing surface is flattened.