JP2019042755A - Method and system for treatment of artificial diamond coating region - Google Patents

Abstract

To provide a method for improving crystallinity of diamond in an artificial diamond coating region which is provided on a work-piece.SOLUTION: A method for treatment of an artificial diamond coating region includes: a step at which an ultrashort pulse laser Lf, of which a pulse width is 1 femtosecond or more and 10 pico seconds or less, is emitted from an ultrashort pulse laser source 10; a step at which the ultrashort laser beam Lf is applied onto a work-piece processed surface 5a, on which artificial diamond coating is performed, via an optical system device 20 or 55 so that fluence of the ultrashort pulse laser Lf on the work-piece processed surface 5a becomes less than a processing threshold of the artificial diamond coating region; and a step at which a relative position or a relative attitude of the ultrashort pulse laser Lf applied via the optical system device 20 or 55 and the work-piece processed surface 5a is controlled, and the ultrashort pulse laser Lf applied via the optical system device 20 or 55 is scanned to the work-piece processed surface 5a.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a method and system for processing an artificial diamond coating region, and more particularly to a method and system for improving the crystallinity of an artificial diamond coating.

  A technique for applying an artificial diamond coating to a blade portion of a cutting tool or the like is known. For example, Patent Document 1 discloses that an artificial diamond coating is applied to the blade portion in order to improve the cutting performance of the blade in which the blade portion made of continuous chevron teeth is formed. Further, Patent Document 2 discloses that an artificial diamond coating is applied to the side surface of the cutting edge portion of the cutting tool in order to prevent burrs from being generated in the soft metal when cutting the soft metal using the cutting tool. Disclose. In addition, various techniques have been reported for artificial diamond or DLC (Diamond Like Carbon) coating (see Non-Patent Documents 1 to 11).

Japanese Patent Laid-Open No. 2006-55407 JP 2004-42195 A

Hitoshi Kakutani, “New development of high-pressure synthetic diamond”, Journal of Precision Engineering, Vol. 76, no. 12, 2010 Akita Hatta, Taku Sumitomo, Akio Hiraki, Toshimichi Ito, “Synthesis of High Quality Diamond by Plasma CVD”, Journal of Plasma and Fusion Research, Vol. 76, no. 9, 2000 Masayoshi Watanabe and Masanori Yoshikawa, “Cutting of Ceramics with Diamond Coating Cutting Tools”, Journal of Precision Engineering, Vol. 56, no. 9, 2009 Htet Sein, Wagar Ahmed, Mark Jackson, Robert Woodwards, Riccardo Polini, "Performance and characterisation of CVD diamond coated, sintered diamond and WC-Co cutting tools for dental and micromachining applications", Thin Solid Films, Vol. 447-448, 30, 2004 Diane. S. knight, William. B. White, “Characterization of diamond films by Raman spectroscopy”, Journal of Materials Research, Vol. 4, Issue 2, 1989 M.M. Pandey, R.A. D 'Cunha, A. K. Tyagi, “Defects in CVD diamond: Raman and XRD studies”, Journal of Alloys and Compounds, Vol. 333, Issues 1-2, 2002 Hiroyuki Kuriyama, Seiichi Kiyama, Shigeru Noguchi, Takashi Kuwahara, Satoshi Ishida, Tomoyuki Nohda, Keiichi Sano, Hiroshi Iwata, Hiroshi Kawata, Masato Osumi, "Enlargement of Poly-Si Film Grain Size by Eximer Laser Annealing and Its Application to High Performance Poly -Si Thin Film Transistor ", Jpn. Appl. Phys. 1991 J. et al. W. Lee, H.C. Shichijo, H.C. L. Tsai, R.A. J. et al. Matyi, “Defect reduction by thermal annealing of GaAs layers grown by molecular beam epitaxy on Si substrates”, Appl. Phys. Lett, 1987 T.A. Sameshima, S .; Usui, M.M. Sekiya, “XeCl Eximer laser annealing used in the fabrication of poly-Si TFT's”, IEEE Electron Device Letters, 1986 Yuki Tsuji, “Complete repair of single crystal Si grinding damage by high-speed laser irradiation” P. Merel, M.M. Tabbal, M.M. Chaker, S .; Moisa, J. et al. Margot, “Direct evaluation of the sp3 content in diamond-like-carbon films by XPS”, Applied Surface Science, 1998. Fumihiro Itoigawa, Kyoji Inoue, Atsushi Ono, Masaaki Sudo, “Modification of CVD diamond coating by femtosecond laser irradiation”, General Incorporated Association, Japan Society of Mechanical Engineers, No. 17-1, Annual Meeting of the Japan Society of Mechanical Engineers 2017

  By the way, diamond consists of carbon sp3 bonds, graphite (graphite) consists of carbon sp2 bonds, and DLC has an amorphous structure (amorphous structure) consisting of both diamond and graphite bonds. That is, in DLC, sp3 which is a diamond bond and sp2 which is a graphite bond are mixed. Since carbon atoms are closely bonded in the sp3 bond, the sp3 bond is stronger than the sp2 bond and contributes to the high hardness peculiar to diamond. Diamonds that are artificially synthesized, such as CVD, often exhibit DLC-like properties. Therefore, when high hardness close to that of diamond is required in an application using artificial diamond, it is desirable to modify the crystal structure to increase the proportion of sp3 bonds. As described above, there is a case where improvement in crystallinity of DLC is desired.

  Accordingly, an object of the present disclosure is to provide a method and system for improving the crystallinity of diamond in an artificial diamond coating region applied to a workpiece.

  According to one aspect of the present disclosure, a method for treating an artificial diamond coating region is provided. The method includes a step of emitting an ultrashort pulse laser having a pulse width of 1 femtosecond or more and 10 picoseconds or less from an ultrashort pulse laser source, and a fluence of the ultrashort pulse laser on a workpiece processing surface coated with an artificial diamond coating. A step of irradiating a workpiece processing surface with an ultra short pulse laser through an optical system device so that the processing threshold of the artificial diamond coating region is less than the processing threshold, and an ultra short pulse laser and a workpiece processing surface irradiated through the optical system device Scanning the workpiece processing surface with an ultrashort pulse laser irradiated through the optical system device.

  According to another aspect of the present disclosure, a system for processing an artificial diamond coating region is provided. The system is provided with an ultrashort pulse laser source that emits an ultrashort pulse laser with a pulse width of 1 femtosecond or more and 10 picoseconds or less, an optical system that adjusts the profile of the ultrashort pulse laser, and an artificial diamond coating. The profile was adjusted with the workpiece holding mechanism that controls the position and orientation of the workpiece surface and the fluence on the workpiece surface of the ultrashort pulse laser whose profile was adjusted being less than the machining threshold of the artificial diamond coating area. A control device for controlling the optical system device and the workpiece holding mechanism is provided so that the ultrashort pulse laser scans the workpiece processing surface.

  According to the present invention, a method and system for improving the crystallinity of diamond in an artificial diamond coating region applied to a workpiece is realized. As a result, the workpiece can be processed with high accuracy, and the tool life can be extended when the workpiece is used as a tool.

It is a block diagram which shows the system for tool manufacture by 1st Embodiment. It is a schematic diagram of the optical system apparatus in 1st Embodiment. It is a figure explaining the surface layer removal by PLG in the 1st Example of 1st Embodiment. It is a figure which shows the SEM image of each area | region in the 1st Example of 1st Embodiment. It is a figure which shows the Raman spectrum of each area | region in the 1st Example of 1st Embodiment. It is a figure which shows the XPS spectrum of C (1s) of each area | region in 1st Example of 1st Embodiment. It is a figure which shows the XPS spectrum of N (1s) of each area | region in the 1st Example of 1st Embodiment. It is a figure which shows the XPS spectrum of O (1s) of each area | region in the 1st Example of 1st Embodiment. It is a figure which shows the result of the X-ray absorption spectroscopy measurement (Auger electron yield method) of each area | region in the 1st Example of 1st Embodiment. It is a figure which shows the result of the X-ray absorption spectroscopy measurement (all the electron yield method) of each area | region in 1st Example of 1st Embodiment. It is a figure explaining the abrasion resistance test of the blade edge | tip in 2nd Example of 1st Embodiment. It is an optical microscope photograph of the blade edge | tip after the cutting test in 2nd Example of 1st Embodiment. It is a figure which shows the SEM image of the blade edge | tip after the cutting test in 2nd Example of 1st Embodiment. It is a block diagram which shows the system for tool manufacture by 2nd Embodiment. It is a figure which shows the SEM image of each area | region in 2nd Embodiment. It is a figure explaining the processing form of a laser. It is a figure explaining the shaping process by PLG. It is a schematic diagram which shows progress of the process to the optical axis direction of the laser in PLG.

<Outline of artificial diamond coating>
1. Artificial diamond While diamond has value as a gemstone, it also has high industrial utility value. Diamond has the highest hardness, high thermal conductivity, and a small coefficient of thermal expansion, thereby being excellent in wear resistance, thermal diffusivity, and thermal shock resistance, and has ideal engineering properties. This property brings about the above high industrial utility value. For this reason, diamond is being applied in a wide range of fields such as the optical field, electrical / electronic field, and machining field, and diamond is widely used for industrial applications such as polishing and cutting. However, the use of natural diamond generally involves problems that the cost of the diamond itself is high, the reserve of natural diamond is small, and that mining is also expensive. Also, diamond is not produced in a fixed shape because it is generated in a very high temperature and high pressure environment inside the earth. Therefore, it is necessary to shape the produced diamond. Still further, the high hardness of diamond is itself an advantage, but results in poor workability. As a result, the use of natural diamond is expensive overall.

  Therefore, in recent years, a technique for artificially synthesizing diamond has been developed. Artificial diamond is synthesized mainly by high-temperature and high-pressure synthesis (HPHT) (for example, see Non-Patent Document 1) or chemical vapor deposition (CVD) (for example, see Non-Patent Document 2).

  With the technology of synthesizing artificial diamond, the application of artificial diamond is being promoted in a wide range of fields such as optical field, electrical / electronic field, and machine work field, as well as natural diamond. The advantage of the artificial diamond synthesis method described above is that the cost for synthesizing diamond is much less than the cost for using natural diamond. Furthermore, although different depending on the synthesis method, artificial diamond has characteristics superior to natural diamond in hardness, thermal / electric conductivity, and electron mobility. This property further facilitates the use of artificial diamond as abrasives, cutting tools, heat sinks, semiconductors and the like. In particular, a multi-layer CVD diamond coating tool in which the surface of the cutting tool is coated with CVD diamond is inexpensive and excellent in cutting performance, and therefore its use is expanding (for example, see Non-Patent Documents 3 and 4).

2. CVD Diamond Coating A method for manufacturing a CVD diamond coating tool is as follows. First, diamond nuclei are generated on the surface of the tool base material. Next, nuclei on the surface of the tool base material grow into diamond grains, and the diamond grains combine to form a film. The diamond film produced by CVD is a polycrystalline diamond. Usually, since a sintering aid such as Co or Si is mixed in a diamond sintered body which is said to be polycrystalline, the proportion of diamond is about 70 to 90%. On the other hand, since vapor-phase synthetic diamond is 100% diamond, it is greatly different from a sintered body.

  CVD diamond coated tools are inexpensive and have excellent cutting performance, and thus have high industrial utility value. However, the difficulty of processing due to high hardness is the same for both natural diamond and artificial diamond. For example, in a CVD diamond coating tool, it takes a lot of time to obtain a sharp cutting edge required for precision cutting by mechanical polishing, and particles fall off and chipping occurs at the cutting edge. It becomes a problem. The existing main diamond processing methods include the above-described polishing processing using diamond powder, electric discharge processing, ion beam processing, and laser processing.

Here, laser processing is based on the interaction between light and material, and the processing form differs depending on the pulse width and power density of the laser. FIG. 15 shows the processing mode with respect to the laser power density and pulse width. As shown in FIG. 15, the form of laser processing is roughly divided into two processes: a thermal process involving evaporation or melting and a non-thermal process using ablation. Thermal processes include removal processes such as cutting and drilling, joining processes such as welding, and heating processes such as surface modification and bending. A typical example of a non-thermal process is ablation processing, which is often used for fine processing such as drilling and grooving of resin and ceramics. In this ablation processing, a very short laser having a light emission time of 10 ⁻¹² to 10 ⁻¹⁵ seconds, such as a picosecond laser or a femtosecond laser, is used. Among these, diamond processing using an ultra-short pulse laser requires only a short processing time, is non-contact processing, and is ablation processing, so that it has a low thermal effect and high accuracy. Suitable for. Therefore, it is expected that further development of diamond laser processing technology will bring industrial advantages.

3. Pulsed laser grinding (PLG)
There is pulse laser grinding (PLG) as a method of forming a tool edge with a laser. FIG. 16 is a schematic diagram of PLG. The short pulse laser L is condensed at a gentle angle by a long-focus single lens, and a cylindrical workable region La is formed (see (a) bird's-eye view). By this workable area La, a cut of several μm is given perpendicularly to the work surface Wa of the workpiece (material) W. And the processable area | region La is repeatedly scanned in parallel with respect to the process surface Wa in the state which contacted the process surface Wa (refer (b) top view and (c) front view). The application of the incision and the scanning are repeated, and the workpiece W is removed by the thickness of the incision to obtain an arbitrary processed surface.

  The greatest advantage of using PLG is that a good processed surface with less unevenness can be obtained. The laser beam spot does not have uniform power and has some distribution. In general, the laser has the strongest central power and becomes weaker toward the outside in the radial direction. Since the laser processing unit is determined by the power distribution, the processing unit is small outside the spot. FIG. 17 is a schematic diagram showing the progress of processing in the direction of the optical axis of the laser. Since the surface finally finished by PLG is formed by the accumulation of the minimum processing units slightly exceeding the processing threshold, a good surface can be obtained as described above.

The following advantages are expected by using the PLG method for tool forming.
(1) Tool shaping is not limited by the hardness of the material to be processed, and even if it is a very hard material such as diamond, processing in a short time is possible.
(2) Since tool forming is non-contact processing, chipping of the blade edge and dropout of particles are suppressed even if the processing object is a brittle material or a sintered material.
(3) Since the laser beam can be transmitted through an optical fiber or the like, it is easy to handle the laser, and it is possible to create a shape freely by applying to other axis machining.
(4) By using a short pulse laser, the processing form is ablation processing. Thereby, even if the object to be processed is a material made of particles such as a sintered material and a binder, uniform processing is possible.
(5) Since a part of the processing object is chemically changed by heat or plasma at the time of laser irradiation, the surface of the processing object can be modified.

4). Crystallinity of artificial diamond Diamond synthesized by CVD may be inferior to natural diamond in chemical quality. When analyzing a diamond coating film synthesized by CVD, the surface is often rich in amorphous carbon as compared to the inside of the film, and often exhibits properties like a DLC film (for example, non-coating). (See Patent Documents 5 and 6).

  This problem may be solved by laser irradiation. It has been reported that an effect of improving crystallinity, that is, an annealing effect, can be obtained by irradiating a crystalline material such as silicon with a short pulse laser (for example, see Non-Patent Documents 7 to 10). It has also been reported that the amount of sp3 carbon in a crystal increases by irradiating the DLC film with a short pulse laser at a low fluence (see, for example, Non-Patent Documents 11 and 12).

  Thus, in the following embodiments, methods and systems for increasing the crystallinity of diamond by increasing the proportion of sp3 bonds in the artificial diamond coating applied to the workpiece are presented.

<First Embodiment>
FIG. 1 is a block diagram showing a system 1 used for a tool manufacturing process according to the first embodiment. The system 1 includes an ultrashort pulse laser source 10, a defocus optical system 20, a work holding mechanism 30, a nanosecond UV laser source 40, a laser scanning device 50, and a control device 60. The workpiece 5 is, for example, a machine tool having a blade portion, and is held by the workpiece holding mechanism 30. The workpiece 5 has a predetermined workpiece processing surface 5a (artificial diamond coating region) composed of a blade portion or the like.

  In general, the ultrashort pulse laser source 10, the defocus optical system 20, and the workpiece holding mechanism 30 mainly contribute to the modification processing (improving crystallinity) of the workpiece processing surface 5a, and mainly the nanosecond UV laser source 40 and The laser scanning device 50 contributes to the shaping process of the workpiece processing surface 5a. Then, the control device 60 controls all or part of the ultrashort pulse laser source 10, the defocus optical system 20, the work holding mechanism 30, the nanosecond UV laser source 40, and the laser scanning device 50 in an integrated or individual manner. . Note that the ultrashort pulse laser source 10, the defocus optical system 20, and the workpiece holding mechanism 30, and the nanosecond UV laser source 40 and the laser scanning device 50 may be individually controlled by different control devices.

  The ultrashort pulse laser source 10 emits an ultrashort pulse laser Lf0 (hereinafter referred to as “ultrashort pulse laser Lf0”). In the present disclosure, a pulse laser having a pulse width of 1 femtosecond to 10 picosecond is referred to as an “ultrashort pulse laser”. Further, the wavelength of the ultrashort pulse laser Lf0 may be about 1 μm.

  The defocus optical system 20 is an example of an optical system device. FIG. 2 shows a schematic diagram of the defocus optical system 20. The defocus optical system 20 includes a condensing lens 21, an iris 22, and a drive unit 23, and defocuses the ultrashort pulse laser Lf0. For convenience of explanation, the ultrashort pulse laser before passing through the lens 21 is referred to as an ultrashort pulse laser Lf0, and the defocused ultrashort pulse laser after passing through the lens 21 is referred to as an ultrashort pulse laser Lf1. Collectively, it will be referred to as an ultrashort pulse laser Lf. The drive unit 23 drives one or both of the lens 21 and the iris 22. When the drive unit 23 adjusts the relative distance of the lens 21 with respect to the workpiece machining surface 5a, the fluence of the ultrashort pulse laser Lf1 on the workpiece machining surface 5a is adjusted. Further, when the drive unit 23 adjusts the diameter of the iris 22, the irradiation range of the ultrashort pulse laser Lf1 on the workpiece processing surface 5a is determined. That is, the fluence and the irradiation range on the workpiece machining surface 5a are determined by relative movement between each element of the defocus optical system 20 and the workpiece machining surface 5a. Note that the focal position of the lens 21 is between the lens 21 and the iris 22, and the optical axis of the ultrashort pulse laser Lf1 intersects (for example, intersects) the workpiece processing surface 5a.

  Returning to FIG. 1, the workpiece holding mechanism 30 is a workpiece fixing stage on which the workpiece 5 is placed. However, the workpiece holding mechanism 30 is not limited to the stage on which the workpiece 5 is placed, but is a mechanism for holding the workpiece 5, a mechanism for holding the workpiece 5 by suction, and a mechanism for holding the workpiece 5 by mutual fitting or insertion. There may be. When the horizontal plane is the XY plane and the vertical direction is the Z direction, the workpiece holding mechanism 30 causes the workpiece 5 to move in the X, Y, and Z directions, rotate in the XY plane, and predetermined with respect to the Z axis. Inclination at an angle and other movements are possible. It is desirable that the workpiece 5 can be moved in the micron order in the scanning direction (for example, the Z direction).

  When the workpiece holding mechanism 30 positions and moves the workpiece 5, irradiation with the ultrashort pulse laser Lf1 is scanned with respect to the workpiece processing surface 5a. In the present embodiment, the relative position or relative attitude between the ultrashort pulse laser Lf1 and the workpiece processing surface 5a is controlled by the operation of the workpiece holding mechanism 30. The relative position or relative attitude is controlled by the ultrashort pulse laser source. 10 and the operation of the defocus optical system 20 are also possible.

  The nanosecond UV laser source 40 emits a nanosecond UV pulse laser Ln0 (hereinafter referred to as “UV pulse laser Ln0”). The nanosecond UV laser source 40 only needs to be suitable for shaping a machine tool or the like by PLG.

The laser scanning device 50 includes a beam forming optical system 51 and a beam scanning mechanism 52.
The beam forming optical system 51 includes a mirror and a lens. The lens is a lens having a long focal length that has a relatively long Rayleigh length with respect to the processing width of the workpiece 5, and is, for example, a single lens or a compound lens, an axicon lens, a DOE (Differential Optical Element), or a combination thereof. With an axico lens and DOE, the beam profile can be arbitrarily shaped or the Rayleigh length can be increased. For convenience of explanation, the pulse laser before passing through the beam forming optical system 51 is referred to as UV pulse laser Ln0, the pulse laser formed after passing through the beam forming optical system 51 is referred to as UV pulse laser Ln1, and both Collectively, it is referred to as a UV pulse laser Ln.

  The beam scanning mechanism 52 may be any mechanism that can scan the workpiece 5 with the UV pulse laser Ln1 with high reproducibility, such as a galvano scanner or a linear stage. The beam scanning mechanism 52 and the beam forming optical system 51 may be integrated. In the same manner as shown in FIG. 16, PLG is executed by scanning the UV pulse laser Ln1 with the laser scanning device 50 (beam scanning mechanism 52). That is, the laser scanning device 50 causes the UV pulse laser Ln1 to contact and scan in parallel with the workpiece processing surface 5a.

  The control device 60 includes a CPU 60a, a memory 60b, and an input / output interface 60c. The CPU 60 a includes a laser control unit 61, an optical system control unit 62, a stage control unit 63, a laser control unit 64, a scanning control unit 65, and an overall control unit 66. Each part of the CPU 60a, the memory 60b, and the input / output interface 60c are connected in such a manner that data and signals can be exchanged with each other via a bus. The memory 60b includes memories such as a ROM and a RAM that store programs, data, and the like. The input / output interface 60c includes an input unit such as a keyboard, a mouse, and a touch panel, and an output unit such as a display (touch panel) and a speaker.

  The laser controller 61 controls on / off of the emission of the ultrashort pulse laser Lf0 by the ultrashort pulse laser source 10. In addition, the pulse width, wavelength, power, and the like of the ultrashort pulse laser Lf0 may be set or controlled via the laser control unit 61, or may be set in the ultrashort pulse laser source 10. In the latter case, the laser control unit 61 controls only on / off of emission of the ultrashort pulse laser Lf0 by the ultrashort pulse laser source 10.

  The optical system control unit 62 controls the position or orientation of the lens 21 and the opening of the iris 22 via the drive unit 23 of the defocus optical system 20, and adjusts the profile of the ultrashort pulse laser Lf1 to adjust the workpiece processing surface 5a. The fluence and the irradiation range of the ultrashort pulse laser Lf1 are adjusted. The stage control unit 63 controls the operation of the workpiece holding mechanism 30 to control the plane movement, vertical movement, rotation, inclination, and the like of the workpiece 5, that is, the workpiece processing surface 5a.

  The laser control unit 64 controls on / off of emission of the UV pulse laser Ln0 by the nanosecond UV laser source 40. Further, the pulse width, wavelength, power, and the like of the UV pulse laser Ln0 may be set or controlled via the laser control unit 64, or may be set in the nanosecond UV laser source 40. In the latter case, the laser control unit 64 controls only the emission of the UV pulse laser Ln0 from the nanosecond UV laser source 40.

  The scanning control unit 65 controls scanning of the UV pulse laser Ln1 with respect to the workpiece 5 by the laser scanning device 50 (beam scanning mechanism 52). Accordingly, the UV pulse laser Ln1 is reciprocally scanned or unidirectionally scanned in parallel with the workpiece processing surface 5a in a state of being in parallel with the workpiece processing surface 5a. Further, the distance between the optical axis of the UV pulse laser Ln1 and the workpiece processing surface 5a (that is, the contact level of the UV pulse laser Ln1 with respect to the workpiece processing surface 5a) is adjusted by the scanning control unit 65 and the beam scanning mechanism 52. May be.

  In the reforming process, the overall control unit 66 synchronizes on / off of the ultrashort pulse laser Lf0 by the laser control unit 61 and scanning of the ultrashort pulse laser Lf1 on the workpiece processing surface 5a by the stage control unit 63. Reproduce and repeat the synchronous operation. Further, in the shaping process, the overall control unit 66 synchronizes the on / off of the UV pulse laser Ln0 by the laser control unit 64 and the scan of the UV pulse laser Ln1 with respect to the workpiece processing surface 5a by the scan control unit 65. Reproduce and repeat the action. Note that the scanning of the UV pulse laser Ln1 may be performed by the work holding mechanism 30 via the stage control unit 63 instead of or along with the operation of the laser scanning device 50 via the scanning control unit 65. When the order or repetition of the reforming process and the shaping process is defined, the overall control unit 66 can cause the reforming process and the shaping process to be executed as a series of processes.

  As described above, the system 1 can be used, for example, in the production of a tool having a blade portion. The manufacturing method by the system 1 includes a shaping process and a modification process for the workpiece processing surface 5a. The order of the shaping process and the reforming process is not limited. That is, the reforming process may be performed after the shaping process, or the shaping process may be performed after the reforming process. Below, the 1st Example and 2nd Example regarding tool manufacture are shown.

<First example of the first embodiment>
In the present example, the workpiece machining surface 5a coated with the CVD multilayer diamond coating was irradiated with the ultrashort pulse laser Lf at a low fluence, and the change in crystallinity on the workpiece machining surface 5a was confirmed. The work surface layer was removed by PLG, and the exposed region was irradiated with an ultrashort pulse laser Lf at a low fluence.

  FIG. 3 is a diagram for explaining surface layer removal by PLG in the present embodiment. The workpiece 5 has a base material portion 5b and a multilayer CVD diamond coating region 5c. As shown in FIG. 3A, a beam-like UV pulse laser Ln is scanned with respect to one surface of the multilayer CVD diamond coating region 5c. Thereby, as shown in FIG. 3B, a part 5d of the multilayer CVD diamond coating region 5c is removed. As a result, as shown in FIG. 3C, an exposed surface 5e of the multilayer CVD diamond coating region 5c is obtained.

The irradiation conditions (PLG conditions) of the UV pulse laser Ln1 in this example are shown below.
Wavelength: 355nm
Power: 2.8W
Pulse width: 7ns
Frequency: 15kHz
Focal length: 100mm
Spot diameter: 20 μm
Power density: 8.4 GW / cm ²
Scanning speed: 30mm / s

Next, as a modification treatment, the exposed surface 5e obtained by the PLG was irradiated with a low fluence ultrashort pulse laser Lf1. The region irradiated with the ultrashort pulse laser Lf is referred to as an irradiation region 5f. It was confirmed that the surface of the workpiece 5 was removed (that is, processed) when the fluence was 16.2 mJ / cm ² or more. Therefore, the modification treatment is performed at a fluence of less than 16.2 mJ / cm ² . In the following description, a fluence of less than 16.2 mJ / cm ² is referred to as “low fluence”.

The irradiation conditions of the ultrashort pulse laser Lf in this example are shown below.
Wavelength: 1041nm
Pulse width: 550 fs
Frequency: 100kHz
Spot diameter at the focal point: 2 μm
Fluence: 5.6, 10.0, 14.9, 16.2 mJ / cm ²
Scanning speed: 2.0mm / s
Number of scans: 10, 30, 50

4A to 4E show SEM images of the irradiation region 5f in this example. In FIG. 4, (a) is a SEM image when the ultrashort pulse laser is not irradiated, (b) ~ (e), respectively, fluence ^{5.9mJ / cm 2, 6.8mJ / cm} 2 , 7.9 mJ / cm ² , 9.2 mJ / cm ² . When this SEM image was acquired, the region irradiated by the low fluence ultrashort pulse laser Lf was line processed by laser processing. FIGS. 4B to 4E show this line processed portion. In each SEM image of FIG. 4, the left side of the center is the original surface, and the right side is an area inside the coating exposed by PLG (area between white lines). As shown in FIG. 4, no substantial difference in the surface state due to the difference in fluence was confirmed on the SEM image.

  In order to confirm the effect of the reforming treatment, the ultrashort pulse laser unirradiated region (hereinafter referred to as “unirradiated region”) and the irradiated region 5f are analyzed by Raman spectroscopy, XPS (X-ray photoelectric spectroscopy), synchrotron X-ray absorption spectroscopy measurement with light and XDR (X-ray diffraction) measurement were performed. The results of each analysis are shown below.

(1) Raman spectroscopic analysis FIGS. 5A to 5E show Raman spectra of the unirradiated region and the irradiated region 5f in this example. In each figure of FIG. 5, a horizontal axis is a Raman shift (cm ^<-1> ), and a vertical axis | shaft is intensity | strength (arbitrary unit). In FIG. 5, (a) is a Raman spectrum when the ultrashort pulse laser is not irradiated, (b) ~ (e), respectively, fluence ^{5.6mJ / cm 2, 6.8mJ / cm} 2 , 7.9 mJ / cm ² , 9.2 mJ / cm ² . As can be seen from FIGS. 5A to 5E, the peak intensity of the D band in the vicinity of 1350 cm ⁻¹ was increased by low fluence irradiation. It can be seen that the amount of increase in the peak intensity of the D band is large with respect to the increase in fluence. That is, when a CVD diamond multilayer film is irradiated with an ultrashort pulse laser Lf at a low fluence, the Raman spectrum approaches a state having a D band peak characteristic of diamond composed of sp3 carbon, that is, the crystallinity of the artificial diamond It can be seen that the reforming due to the improvement was performed.

(2) Analysis by XPS FIG. 6 shows XPS spectra of C (1s) in the unirradiated region and the irradiated region 5f in this example. In FIG. 7, the XPS spectrum of N (1s) of the unirradiated area | region and the irradiation area | region 5f in a present Example is shown. FIG. 8 shows XPS spectra of O (1s) in the unirradiated region and the irradiated region 5f in this example. In each figure, the horizontal axis represents the binding energy (eV), and the vertical axis represents the XPS intensity (arbitrary unit). The data shows the XPS intensity of the surface before the PLG processing (Surface) and the surface of the unirradiated region after the PLG processing (Inner part). Moreover, the data, the surface of the irradiated region 5f in the case of irradiation with 5.6J / cm ^2, the surface of the irradiated region 5f in the case of irradiation with 10.0J / cm ^2, irradiation with 14.9J / cm ² The XPS intensity of the surface of the irradiation region 5f in the case of, and the surface of the irradiation region 5f in the case of irradiation at 16.2 mJ / cm ² are shown.

Table 1 shows the results of quantitative analysis calculated from the respective peak area intensities based on FIGS. The numerical value is an arbitrary unit. According to Table 1, it was found that the amount of C (1s) increased, the amount of N (1s) decreased, and the amount of O (1s) decreased with an increase in the fluence in the irradiated region 5f. .

Table 2 shows the amount of sp3 carbon relative to the fluence obtained as a result of separating the C (1s) peak. Each value is normalized with the value of the unirradiated area. At least fluence to 14.9J / cm ² was confirmed that also increases sp3 carbon content with increasing fluence, it found that an increase in sp3 carbon content in the fluence of less than 16.2J / cm ² is expected It was. Thereby, the modification effect by irradiation of the ultrashort pulse laser at a low fluence was confirmed.

(3) X-ray absorption spectroscopic measurement with synchrotron light X-ray absorption spectroscopic measurement with synchrotron light was performed on the unirradiated region (ultrashort pulse laser unirradiated region) and irradiated region (ultrashort pulse laser irradiated region). . The irradiation conditions of the ultrashort pulse laser are as follows.
Wavelength: 1045nm
Pulse width: 700fs
Output power: 400mW
Frequency: 100kHz
Fluence: 14.9 mJ / cm ²

  9A and 9B show the results of the X-ray absorption spectroscopy measurement. FIG. 9A shows the measurement result by the Auger electron yield method (AEY), and FIG. 9B shows the measurement result by the total electron electron yield method (TEY). 9A and 9B, the horizontal axis represents energy E (eV), and the vertical axis represents normalized electron yield (× μE). According to FIG. 9A and FIG. 9B, the value of the C—O bond decreases in the irradiated region (solid line) with respect to the non-irradiated region (broken line), and the value of the C—C bond and its lower band side (near 290 eV). It was confirmed that the value increased. The decrease in the value of the C—O bond is considered to be due to the removal of the oxide layer on the surface by irradiation with the ultrashort pulse laser. The increase in the value of the CC bond and the value on the low band side represents a change to a value peculiar to the diamond crystal, indicating that diamond was formed in the surface layer of the ultrashort pulse laser irradiation region. Yes.

(4) XRD measurement In order to confirm whether the irradiation area | region obtained in said (3) was crystalline or amorphous, XRD measurement was implemented. As a result of X-ray analysis measurement by oblique incidence of 0.2 °, the peak representing diamond characteristics increased in the ultra-short pulse laser irradiated region compared with the unirradiated region, and the crystallinity was improved by 20%. Was confirmed.

  As described above, in this embodiment, the work processing surface 5a coated with the CVD multilayer diamond coating is irradiated with the ultrashort pulse laser Lf at a low fluence, thereby improving the crystallinity on the work processing surface 5a. confirmed.

<Second Example of First Embodiment>
In this example, the ultra-short pulse laser Lf was irradiated at a low fluence on the cutter coated with the CVD multi-layer diamond coating, and a change in the wear resistance of the cutter was confirmed. First, a cutting tool (blade part) in which a superalloy base material was coated with an artificial diamond coating was shaped by PLG. The shaped processing surface was irradiated with an ultrashort pulse laser at a low fluence. And 1000 m of cutting was implemented using the blade after this irradiation.

The shaping method using PLG is the same as that described in the first embodiment (see FIG. 3). The irradiation conditions (PLG conditions) of the UV pulse laser are as follows (similar to the first embodiment).
Wavelength: 355nm
Power: 2.8W
Pulse width: 7ns
Frequency: 15kHz
Focal length: 100mm
Spot diameter: 20 μm
Power density: 8.4 GW / cm ²
Scanning speed: 30mm / s

The irradiation conditions of the ultrashort pulse laser in the modification process are as follows.
Wavelength: 1041nm
Pulse width: 550 fs
Frequency: 100kHz
Spot diameter at the focal point: 2 μm
Fluence: 14.9 mJ / cm ²
Scanning speed: 2.0mm / s
Number of scans: 50 times

  The wear resistance is measured by scanning a tool T having a blade E with respect to a round bar B as shown in FIG. Specifically, a blade E that has not been irradiated with an ultrashort pulse laser (hereinafter referred to as “unirradiated blade”) and a blade E that has been irradiated with an ultrashort pulse laser (hereinafter referred to as “irradiated blade”) are round. It was carried out by a cutting test in which the bar B was subjected to face cutting for 1000 m each. The test results are as follows.

  In FIG. 11, the optical microscope photograph of the blade edge | tip of each blade part after a cutting test is shown. (A) of FIG. 11 is a photograph of an unirradiated blade part, and (b) is a photograph of an irradiated blade part. It can be seen that the non-irradiated blade portion and the irradiated blade portion also did not have chipping or peeling, and the wear progressed constantly.

  FIG. 12 shows SEM images of the unirradiated blade portion and the irradiated blade portion. (A) of FIG. 12 is a SEM image of an unirradiated blade part, and (b) is an SEM image of an irradiated blade part. In each SEM image, the upper side (upper side of two adjacent white belt-like portions extending in the lateral direction) is a rake face, and the lower side (lower side of the white belt-like portion) is a flank face. When attention is paid to the wear width of the flank, it can be seen that the irradiated blade portion has a smaller amount of wear than the non-irradiated blade portion. This indicates that the retraction amount of the blade edge is suppressed by the surface modification by the irradiation with the ultrashort pulse laser. That is, it was confirmed that the crystallinity as diamond of the artificial diamond coating was improved and the hardness was increased by irradiation of the ultrashort pulse laser at a low fluence.

  As described above, in this embodiment, the blade (blade portion) coated with the CVD multilayer diamond coating is irradiated with the ultrashort pulse laser Lf at a low fluence, thereby improving the wear resistance of the blade portion. confirmed.

As described above, the system 1 for processing an artificial diamond coating region according to the present embodiment includes an ultrashort pulse laser source 10 that emits an ultrashort pulse laser Lf having a pulse width of 1 femtosecond or more and 10 picoseconds or less, and an ultrashort laser source 10. A defocus optical system 20 (optical system apparatus) that adjusts the profile of the pulse laser Lf, a workpiece holding mechanism 30 that controls the position and orientation of the workpiece processing surface 5a on which the artificial diamond coating has been applied, and an ultra-profile profile that has been adjusted In a state where the fluence of the short pulse laser Lf on the workpiece processing surface 5a is less than the processing threshold of the artificial diamond coating region, for example, less than 16.2 mJ / cm ² , the ultrashort pulse laser Lf whose profile is adjusted moves the workpiece processing surface 5a. The defocus optical system 20 and the work holding mechanism 30 are set so as to scan. A control device 60 for controlling is provided.

The method for processing the artificial diamond coating region according to the present embodiment includes a step of emitting an ultrashort pulse laser Lf having a pulse width of 1 femtosecond or more and 10 picoseconds or less from the ultrashort pulse laser source 10, and an artificial diamond coating. Via the defocus optical system 20 (optical system apparatus) so that the fluence of the ultrashort pulse laser Lf on the applied workpiece processing surface 5a is less than the processing threshold of the artificial diamond coating region, for example, less than 16.2 mJ / cm ^2. Irradiating the workpiece machining surface 5a with the ultrashort pulse laser Lf, and controlling the relative position or relative position between the ultrashort pulse laser Lf irradiated via the defocus optical system 20 and the workpiece machining surface 5a, An ultrashort pulse laser Lf irradiated through the defocus optical system 20 is used as a workpiece processing surface 5a. Scanning with respect to.

In this way, the profile of the ultrashort pulse laser Lf is adjusted so that the fluence of the ultrashort pulse laser Lf on the workpiece processing surface 5a on which the artificial diamond coating is applied is less than 16.2 mJ / cm ² , and this ultrashort pulse The laser beam Lf is irradiated and scanned on the workpiece processing surface 5a. Thereby, the artificial diamond coating on the workpiece processing surface 5a is modified, and the crystallinity of diamond in the artificial diamond coating region is improved. In addition, this makes it possible to process the workpiece 5 with high accuracy and to extend the tool life when the workpiece 5 is used as a tool.

Furthermore, the fluence of the ultrashort pulse laser Lf in the workpiece processed surface 5a is preferably at 5.6mJ / cm ² or more 14.9mJ / cm ² or less, 10.0 mJ / cm ² or more 14.9mJ / cm ² The following is more preferable. Thereby, the effect of improving the crystallinity by the above modification treatment can be further obtained.

  In particular, in the present embodiment, the defocus optical system 20 is configured to defocus the ultrashort pulse laser Lf in a state where the optical axis of the ultrashort pulse laser Lf intersects the workpiece processing surface 5a. That is, the adjustment step includes a step of defocusing the ultrashort pulse laser Lf in a state where the optical axis of the ultrashort pulse laser Lf intersects the workpiece processing surface 5a. Thereby, the adjustment of the fluence of the ultrashort pulse laser Lf on the workpiece processing surface 5a can be easily and reliably performed.

  Further, the system 1 includes a nanosecond UV laser source 40 that emits a nanosecond UV pulse laser (UV pulse laser Ln), a beam forming optical system 51 that forms a beam of the UV pulse laser Ln, and a beam-formed UV pulse. A beam scanning mechanism 52 that moves the laser Ln in a direction perpendicular to the optical axis direction, and the control device 60 makes the beam-formed UV pulse laser Ln contact and scan in parallel with the workpiece processing surface 5a. The beam scanning mechanism 52 or the work holding mechanism 30 is configured to be controlled. That is, in the above method, the step of emitting the UV pulse laser Ln from the nanosecond UV laser source 40, the step of forming the beam of the UV pulse laser Ln by the beam forming optical system 51, and the step of forming the beam-formed UV pulse laser Ln as a workpiece. A step of shaping the workpiece processing surface 5a by contacting and scanning in parallel with the processing surface 5a. Thereby, the shaping process of the workpiece | work 5 by PLG can be easily added to the said modification | reformation process.

  The artificial diamond coating may be a multilayer diamond coating formed by CVD. The above method and system 1 can be suitably applied to a workpiece having a CVD multilayer diamond coating.

  In particular, the workpiece processing surface 5a is preferably a part or all of the cutting edge of the cutting tool. The method and system 1 can be suitably applied to a cutting tool that requires hardness and wear resistance such as a blade.

<Second Embodiment>
In the first embodiment, the configuration in which the shaping process is performed by the nanosecond UV pulse laser (UV pulse laser) Ln and the modification process is performed by the ultrashort pulse laser Lf is shown. In the present embodiment, a configuration in which both processes are performed by the ultrashort pulse laser Lf is shown. Specifically, in the configuration of the first embodiment, the ultrashort pulse laser Lf is defocused and irradiated onto the workpiece processing surface 5a. However, in the configuration of this embodiment, the ultrashort pulse laser Lf is beam-formed. Then, the work processing surface 5a is irradiated with contact.

  FIG. 13 is a block diagram showing the system 2 used for the tool manufacturing process according to the second embodiment. The system 2 includes an ultrashort pulse laser source 10, a work holding mechanism 30, a laser scanning device 55, and a control device 600. In the present embodiment, the same reference numerals are given to substantially the same components as those in the first embodiment, and the overlapping description is omitted or simplified. Similarly to the system 1 of the first embodiment, the system 2 of this embodiment can also be used for cutting edge shaping and modification of a tool having a blade portion.

  The laser scanning device 55 is an example of an optical system device. The laser scanning device 55 includes a beam forming optical system 56 and a beam scanning mechanism 52. The beam forming optical system 56 includes a mirror, a lens, and the like. The lens is a lens having a long focal length that has a relatively long Rayleigh length with respect to the processing width of the workpiece 5. A lens, DOE, or a combination thereof. Further, the beam forming optical system 56 may include a spatial modulator. With an axico lens and DOE, the beam profile can be arbitrarily shaped or the Rayleigh length can be increased. Further, the beam profile can be made variable by the spatial modulator. For convenience of explanation, an ultrashort pulse laser before passing through the beam forming optical system 56 is referred to as an ultrashort pulse laser Lf0, and a pulse laser formed after passing through the beam forming optical system 56 is referred to as an ultrashort pulse laser Lf2. Both are collectively referred to as an ultrashort pulse laser Lf. The laser scanning device 55 makes the ultrashort pulse laser Lf2 contact and scan in parallel with the workpiece processing surface 5a.

  The control device 600 includes a CPU 60a, a memory 60b, and an input / output interface 60c. The CPU 60a includes a laser control unit 61, a stage control unit 63, a scanning control unit 65, and an overall control unit 66.

  The scanning control unit 65 controls scanning of the ultrashort pulse laser Lf2 with respect to the workpiece 5 by the laser scanning device 55 (beam scanning mechanism 52). Thereby, one-way scanning or reciprocating scanning can be performed on the workpiece machining surface 5a in a state where the ultrashort pulse laser Lf2 is in contact with the workpiece machining surface 5a in parallel. Further, the distance between the optical axis of the ultrashort pulse laser Ln2 and the workpiece machining surface 5a (that is, the contact level of the ultrashort pulse laser Lf2 with respect to the workpiece machining surface 5a) can be adjusted by the scanning controller 65 and the beam scanning mechanism 52. .

  The overall control unit 66 synchronizes the output of the ultrashort pulse laser Lf0 from the laser control unit 61 and the scan of the ultrashort pulse laser Lf2 to the workpiece processing surface 5a by the scan control unit 65 in the reforming process and the shaping process. This synchronous operation is reproduced and repeated. The scanning of the ultrashort pulse laser Lf2 may be performed by the work holding mechanism 30 via the stage control unit 63 instead of or along with the operation of the beam scanning mechanism 52 via the scanning control unit 65. When the order or repetition of the reforming process and the shaping process is defined, the overall control unit 66 can cause the reforming process and the shaping process to be executed as a series of processes.

  In both the shaping process (PLG) and the modification process, the workpiece surface 5a is irradiated with the beam of the ultrashort pulse laser Lf2. However, the energy (fluence) on the workpiece processing surface 5a of the ultrashort pulse laser Lf2 during the shaping process is higher than that during the modification process, and the fluence during the shaping process is higher than the machining threshold value of the workpiece 5, and the modification process. It is desirable that the time fluence is lower than the processing threshold. The beam profile of the ultrashort pulse laser Lf2 is adjusted by the ultrashort pulse laser source 10 or the laser scanning device 55 (beam forming optical system 56). In particular, during the shaping process using PLG, a beam having a profile that rises sharply from low intensity to high intensity from the outside of the beam to the center of the beam is formed. That is, the beam contact level of the ultrashort pulse laser Lf2 with respect to the workpiece processing surface 5a is configured to be high for the shaping process and low for the modification process.

  The contact level of the beam of the ultrashort pulse laser Lf2 with respect to the workpiece processing surface 5a and the fluence on the workpiece processing surface 5a associated therewith may be adjusted by the beam scanning mechanism 52 or by the workpiece holding mechanism 30. Alternatively, the fluence may be adjusted by changing the beam profile by the beam forming optical system 56. When the fluence is adjusted by the beam scanning mechanism 52 or the workpiece holding mechanism 30, the distance between the optical axis of the ultrashort pulse laser Lf2 and the workpiece processing surface 5a is adjusted. That is, the laser scanning device 55 or the workpiece holding mechanism 30 is controlled so that the ultrashort pulse laser Lf having the same profile is in contact with the workpiece processing surface 5a at different levels. As a result, the modification process and the shaping process can be performed only by controlling the positioning of the ultrashort pulse laser Lf2 and the workpiece processing surface 5a, and the control configuration on the beam forming side is simplified. When the fluence is adjusted by the beam forming optical system 56, the intensity rises from the outside of the beam to the center of the beam with the positional relationship between the optical axis of the ultrashort pulse laser Lf2 and the workpiece processing surface 5a being fixed. Is adjusted. As a result, the modification process and the shaping process can be performed only by adjusting the profile of the ultrashort pulse laser Lf, and the control configuration on the scanning side is simplified.

  When the reforming process is performed prior to the shaping process, first, in the reforming process, the workpiece machining surface is at a contact level such that the energy (fluence) of the ultrashort pulse laser Lf2 does not exceed the machining threshold of the workpiece 5. 5a is contact-irradiated, and the beam is scanned parallel to the workpiece processing surface 5a. As a result, the workpiece machining surface 5a is modified and the machining threshold is increased. Thereafter, in the shaping process, the workpiece machining surface 5a is contact-irradiated at a contact level such that the beam energy (fluence) of the ultrashort pulse laser Lf2 is equal to or higher than the machining threshold of the workpiece 5, and the beam is parallel to the workpiece machining surface 5a. Scanned. Thereby, the shaping process of the workpiece processing surface 5a is performed. A configuration in which the modification process is performed after the shaping process according to the machining threshold value of the workpiece 5 is also possible.

  FIG. 14 shows an SEM image of the work surface 5a having a CVD multilayer diamond coating. 14A is an SEM image when the modification process and the shaping process are performed, and FIG. 14B is an SEM image when only the shaping process is performed without the modification process (each In the figure, irradiation conditions differ between the upper and lower figures). As shown in FIG. 14, it was found that the unevenness (for example, the unevenness caused by the nano-periodic structure) on the workpiece processing surface 5a is reduced by performing the reforming process, so that highly accurate processing is possible.

As described above, the system 2 for processing the artificial diamond coating region according to the present embodiment includes the ultrashort pulse laser source 10 that emits the ultrashort pulse laser Lf having a pulse width of 1 femtosecond or more and 10 picoseconds or less, and the ultrashort pulse laser source 10. A laser scanning device 55 (optical device) that adjusts the profile of the pulse laser Lf, a workpiece holding mechanism 30 that controls the position and orientation of the workpiece processing surface 5a on which the artificial diamond coating is applied, and an ultra-short profile that has been adjusted With the fluence of the pulse laser Lf on the workpiece machining surface 5a being less than the machining threshold of the artificial diamond coating region, for example, less than 16.2 mJ / cm ² , the ultrashort pulse laser Lf whose profile is adjusted scans the workpiece machining surface 5a. The laser scanning device 55 and the work holding mechanism 30 are controlled so as to And a control device 60.

In addition, the method for processing the artificial diamond coating region according to the present embodiment uses an ultrashort pulse laser Lf having a pulse width of 1 femtosecond or more and 10 picoseconds or less from the ultrashort pulse laser source 10 as in the first embodiment. The laser scanning device so that the fluence of the ultrashort pulse laser Lf on the workpiece processing surface 5a on which the artificial diamond coating is applied is less than the processing threshold of the artificial diamond coating region, for example, less than 16.2 mJ / cm ^2. The step of irradiating the workpiece machining surface 5a with the ultrashort pulse laser Lf via 55 (optical system device) and the relative position between the ultrashort pulse laser Lf irradiated via the laser scanning device 55 and the workpiece machining surface 5a or The relative attitude is controlled, and the ultrashort pulse laser Lf irradiated through the laser scanning device 55 is turned on. Scanning the workpiece surface 5a.

  Thereby, also in this embodiment, it becomes possible to improve the crystallinity of diamond in the artificial diamond coating region applied to the workpiece 5 as in the first embodiment. As a result, the workpiece 5 can be processed with high accuracy, and the tool life can be extended when the workpiece 5 is used as a tool having a blade portion.

  Particularly in the present embodiment, the laser scanning device 55 includes a beam forming optical system 56 that forms a beam of the ultrashort pulse laser Lf and a beam scanning mechanism that moves the formed ultrashort pulse laser Lf in a direction perpendicular to the optical axis direction. The control device 600 is configured to control the beam scanning mechanism 52 or the work holding mechanism 30 so that the beam-formed ultrashort pulse laser contacts and scans in parallel with the work processing surface 5a. The That is, the irradiating step includes a step of beam-forming the ultrashort pulse laser Lf and a step of bringing the beam-formed ultrashort pulse laser Lf into contact with the workpiece processing surface in parallel. The method includes a step of scanning an ultrashort pulse laser Lf in parallel with the surface parallel to the workpiece processing surface. Thereby, the adjustment of the fluence of the ultrashort pulse laser Lf on the workpiece processing surface 5a can be easily and reliably performed.

  Further, the control device 600 switches the energy applied to the workpiece machining surface 5a from the beam-formed ultrashort pulse laser Lf between a value less than the machining threshold of the workpiece machining surface 5a and a value greater than or equal to the machining threshold. The beam scanning mechanism 52 or the workpiece holding mechanism 30 is configured to be controlled. That is, in the above method, the ultrashort pulse laser Lf is applied to the workpiece machining surface 5a via the laser scanning device 55 so that the fluence of the ultrashort pulse laser Lf on the workpiece machining surface 5a is equal to or greater than the machining threshold of the workpiece machining surface 5a. The step of bringing the ultrashort pulse laser Lf into contact with the workpiece machining surface 5a is controlled by controlling the relative position or the relative posture between the workpiece pulsed surface 5a and the ultrashort pulse laser Lf in parallel contact with the workpiece machining surface 5a. And scanning for 5a. Thereby, by adjusting the fluence of the ultrashort pulse laser Lf, the shaping process and the reforming process can be performed using one ultrashort pulse laser source 10, and the configuration and control of the system 2 are simplified. Can do.

Similarly to the first embodiment, in the modification process, the fluence of the ultrashort pulse laser Lf on the workpiece processing surface 5a is preferably 5.6 mJ / cm ² or more and 14.9 mJ / cm ² or less, It is more preferable that it is 10.0 mJ / cm ² or more and 14.9 mJ / cm ² or less. As in the first embodiment, the artificial diamond coating may be a multilayer diamond coating formed by CVD. Moreover, it is preferable that the workpiece processing surface 5a is a part or all of the cutting edge of the cutting tool as in the first embodiment.

<Modification>
Although preferred embodiments of the present invention have been described above, the present invention can be modified into various modes as shown below, for example.

(1) Modification related to presence / absence of shaping process In each of the above embodiments, the configuration in which both the shaping process and the reforming process are performed in the system 1 or 2 is shown. However, the system 1 or 2 is used only for the reforming process. May be. That is, the workpiece 5 having the workpiece processing surface 5a that has already been shaped (the workpiece 5 having the workpiece processing surface 5a coated with artificial diamond) is held by the workpiece holding mechanism 30 and irradiated with the ultrashort pulse laser Lf at a low fluence. And the modification process by scanning may be performed.

(2) Combination of the first and second embodiments In the first embodiment, the shaping process is executed by beam forming irradiation of a nanosecond UV pulse laser (UV pulse laser) Ln, and the modification process is an ultrashort pulse. This was performed by defocus irradiation of the laser Lf. In the second embodiment, the shaping process and the modification process are performed by the beam forming irradiation of the ultrashort pulse laser Lf. On the other hand, the shaping process is executed by the beam forming irradiation of the UV pulse laser Ln as in the first embodiment, and the modification process is executed by the beam forming irradiation of the ultrashort pulse laser Lf as in the second embodiment. Configuration is also possible. In this case, the beam forming optical system 51 or 56 and the beam scanning mechanism 52 are shared by both the UV pulse laser Ln and the ultrashort pulse laser Lf. The UV pulse laser Ln from the nanosecond UV laser source 40 and the ultrashort pulse laser Lf from the ultrashort pulse laser source 10 incident on the beam forming optical system 51 or 56 are between the shaping process and the modification process. Can be switched.

1, 2 System 5 Work 5a Work surface (DLC coating area)
10 Ultrashort pulse laser source 20 Defocus optical system (optical system equipment)
30 Work holding mechanism 40 Nanosecond UV laser source 50, 55 Laser scanning device (optical system device)
51, 56 Beam forming optical system 52 Beam scanning mechanism 60, 600 Controller Lf Ultrashort pulse laser Ln Nanosecond UV pulse laser (UV pulse laser)

Claims (18)

A method of processing an artificial diamond coating region comprising:
Emitting an ultrashort pulse laser having a pulse width of 1 femtosecond or more and 10 picoseconds or less from an ultrashort pulse laser source;
Irradiate the workpiece surface with the ultrashort pulse laser via an optical system so that the fluence of the ultrashort pulse laser on the workpiece processing surface coated with artificial diamond is less than the processing threshold of the artificial diamond coating region. And steps to
The relative position or relative attitude between the ultrashort pulse laser irradiated through the optical system device and the workpiece processing surface is controlled, and the ultrashort pulse laser irradiated through the optical system device is changed to the workpiece. Scanning the work surface. The method according to claim 1, wherein the processing threshold is 16.2 mJ / cm ² . The method according to claim 1, wherein a fluence on the workpiece processing surface is 5.6 mJ / cm ² or more and 14.9 mJ / cm ² or less. The method according to claim 1, wherein a fluence on the workpiece processing surface is 10.0 mJ / cm ² or more and 14.9 mJ / cm ² or less.   The said irradiating step includes the step of defocusing the ultrashort pulse laser in a state where the optical axis of the ultrashort pulse laser intersects the workpiece processing surface. Method. Emitting a nanosecond UV pulsed laser from a nanosecond UV laser source;
Beam forming the nanosecond UV pulsed laser with a beam forming optical system;
6. The method of claim 5, further comprising: shaping and shaping the workpiece machining surface by contacting and scanning the beamformed nanosecond UV pulsed laser parallel to the workpiece machining surface. The step of irradiating comprises beam forming the ultrashort pulse laser and contacting the beam formed ultrashort pulse laser in parallel with the work surface;
The said scanning step includes the step of scanning in parallel with respect to the said workpiece processing surface the ultra short pulse laser which contacted in parallel with the said workpiece processing surface. Method. The ultrashort pulse laser is brought into contact with the workpiece machining surface in parallel to the workpiece machining surface so that the fluence of the ultrashort pulse laser on the workpiece machining surface is equal to or greater than the machining threshold of the workpiece machining surface. Steps,
Scanning the ultra-short pulse laser with respect to the workpiece machining surface by controlling a relative position or a relative posture between the ultra-short pulse laser and the workpiece machining surface which are in parallel contact with the workpiece machining surface. The method of claim 7, further comprising:   9. A method according to any one of the preceding claims, wherein the artificial diamond coating is a multilayer diamond coating formed by chemical vapor deposition.   The method according to claim 1, wherein the workpiece machining surface is a part or all of a cutting edge of a cutting tool. A system for processing an artificial diamond coating area,
An ultrashort pulse laser source for emitting an ultrashort pulse laser having a pulse width of 1 femtosecond or more and 10 picoseconds or less;
An optical device for adjusting the profile of the ultrashort pulse laser;
A workpiece holding mechanism that controls the position and posture of the workpiece processing surface that has been subjected to artificial diamond coating;
The ultrashort pulse laser with the adjusted profile scans the workpiece processing surface in a state where the fluence on the workpiece processing surface of the ultrashort pulse laser with the adjusted profile is less than the processing threshold of the artificial diamond coating region. And a control device that controls the optical system device and the work holding mechanism. The system of claim 11, wherein the processing threshold is 16.2 mJ / cm ² . The fluence at the workpiece processed surface, configured so that 5.6mJ / cm ² or more 14.9mJ / cm ² or less, the system according to claim 11. The system according to claim 11, wherein the fluence on the workpiece processing surface is configured to be 10.0 mJ / cm ² or more and 14.9 mJ / cm ² or less.   The optical system apparatus includes a defocus optical system that defocuses the ultrashort pulse laser in a state where an optical axis of the ultrashort pulse laser intersects the workpiece processing surface. The system described in. A nanosecond UV laser source emitting a nanosecond UV pulse laser;
A beam forming optical system for beam forming the nanosecond UV pulse laser;
A beam scanning mechanism for moving the beam-formed nanosecond UV pulse laser in a direction perpendicular to the optical axis direction;
The controller is configured to control the beam scanning mechanism or the workpiece holding mechanism such that the beam-formed nanosecond UV pulse laser contacts and scans in parallel with the workpiece processing surface; The system according to claim 15. The optical system apparatus includes a beam forming optical system that forms a beam of the ultrashort pulse laser and a beam scanning mechanism that moves the beam-formed ultrashort pulse laser in a direction perpendicular to the optical axis direction,
The control device is configured to control the beam scanning mechanism or the workpiece holding mechanism so that the beam-formed ultrashort pulse laser contacts and scans in parallel with the workpiece processing surface. Item 15. The system according to any one of Items 11 to 14.   The controller is further configured to switch energy applied to the workpiece machining surface from the beam-formed ultrashort pulse laser between a value less than a machining threshold of the workpiece machining surface and a value greater than or equal to the machining threshold. The system of claim 17, configured to control the beam scanning mechanism or the workpiece holding mechanism.