JP2016221579A - Direct diode laser processing device and processing method for metal plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct diode laser processing device that can cut a work-piece with high quality at high speed.SOLUTION: The direct diode laser processing device comprises: a laser oscillator that oscillates laser light with multiple wavelengths; a transmitting fiber that transmits the laser light with multiple wavelengths oscillated by the laser oscillator; and a laser processor that condenses the laser light with multiple wavelengths transmitted by the transmitting fiber so as to process a work-piece, which performs control so that the wavelengths of the laser light with multiple wavelengths are set to less than 1000 nm, beam parameter products of the laser light with multiple wavelengths are set to 4 mm*mrad-25 mm*mrad and cutting speed of the work-piece is set to 0.1 m/min-60 m/min on the basis of a thickness and a rate of absorption of the work-piece.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a direct diode laser processing apparatus and a sheet metal processing method using the same.

2. Description of the Related Art Conventionally, as a laser processing apparatus for processing a sheet metal, an apparatus using a carbon dioxide (CO ₂ ) laser oscillator, a YAG laser oscillator, or a fiber laser oscillator as a laser light source is known. The fiber laser oscillator has advantages such as better light quality and extremely high oscillation efficiency than the YAG laser oscillator. For this reason, a fiber laser processing apparatus using a fiber laser oscillator is used for industrial purposes, particularly for sheet metal processing (cutting or welding).

  Further, in recent years, a DDL processing apparatus using a direct diode laser (DDL) oscillator as a laser light source has been developed (see Patent Document 1).

US Pat. No. 5,715,270

However, Patent Document 1 merely suggests that may be applied to cutting the DDL machining apparatus, the quality and speed of cutting by DDL processing apparatus are conventionally used CO ₂ laser processing device No specific comparative study has been made to raise the level to a level that can compete with fiber laser processing equipment.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a direct diode laser processing apparatus capable of cutting a workpiece at high speed with good quality and a sheet metal processing method using the same. It is to be.

  According to one aspect of the present invention, a laser resonator that oscillates multi-wavelength laser light, a transmission fiber that transmits multi-wavelength laser light oscillated by the laser resonator, and a multi-wavelength transmitted by the transmission fiber A laser processing machine for condensing the laser beam to process the workpiece, and based on the thickness and absorption rate of the workpiece, the wavelength of the multi-wavelength laser beam is less than 1000 nm, Provided are a direct diode laser processing apparatus that controls a beam parameter product to 4 mm · mrad to 25 mm · mrad and a cutting speed of a workpiece to 0.1 m / min to 60 m / min, and a sheet metal processing method using the same. .

  ADVANTAGE OF THE INVENTION According to this invention, the direct-diode laser processing apparatus which can cut | disconnect a workpiece material with favorable quality at high speed, and the processing method of a sheet metal using the same can be provided.

It is a perspective view which shows an example of the DDL processing apparatus which concerns on embodiment of this invention. FIG. 2A is a side view showing an example of a laser oscillator according to the embodiment of the present invention. FIG. 2B is a front view showing an example of a laser oscillator according to the embodiment of the present invention. It is the schematic which shows an example of the DDL module which concerns on embodiment of this invention. It is the schematic for demonstrating the optical parameter in the DDL processing apparatus which concerns on embodiment of this invention. It is the schematic for demonstrating the incident angle of the laser beam in the DDL processing apparatus which concerns on embodiment of this invention. It is an image which shows the cut surface of the favorable cutting quality of the to-be-processed member which concerns on embodiment of this invention. It is a graph showing the cutting speed ratio of a DDL processing apparatus with respect to the thickness of the mild steel based on 1st Example of this invention, A / d ratio, and the cutting speed ratio of a fiber laser processing apparatus. It is a graph showing the cutting speed ratio of a DDL processing apparatus with respect to the thickness of the aluminum which concerns on 2nd Example of this invention, A / d ratio, and the cutting speed ratio of a fiber laser processing apparatus. FIG. 9A is a graph showing the relationship between the incident angle of the laser beam and the iron absorptance according to the third embodiment. FIG. 9B is a graph showing the relationship between the incident angle of the laser beam and the absorptance of aluminum according to the third embodiment.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  With reference to FIG. 1, an overall configuration of a direct diode laser (hereinafter referred to as “DDL”) processing apparatus according to an embodiment of the present invention will be described. As shown in FIG. 1, a DDL processing apparatus according to an embodiment of the present invention includes a laser oscillator 11 that oscillates multi-wavelength laser light LB, and a transmission fiber (process) that transmits the laser light LB oscillated by the laser oscillator 11. Fiber) 12 and a laser beam machine 13 for condensing the laser beam LB transmitted by the transmission fiber 12 to a high energy density and irradiating the workpiece (workpiece) W.

  The laser processing machine 13 includes a collimator unit 14 that converts the laser light LB emitted from the transmission fiber 12 into substantially parallel light by the collimator lens 15, and the laser light LB converted to substantially parallel light in the X-axis and Y-axis directions. A bending mirror 16 that reflects downward in the Z-axis direction perpendicular to the laser beam, and a processing head 17 that condenses the laser beam LB reflected by the bending mirror 16 with a condenser lens 18. As the collimator lens 15 and the condenser lens 18, for example, a general lens such as a quartz plano-convex lens can be used.

  Although not shown in FIG. 1, a lens driving unit that drives the collimator lens 15 in a direction parallel to the optical axis (X-axis direction) is installed in the collimator unit 14. The DDL processing apparatus further includes a control unit that controls the lens driving unit.

  The laser processing machine 13 further includes a processing table 21 on which the workpiece W is placed, a portal X-axis carriage 22 that moves in the X-axis direction on the processing table 21, and an X-axis direction on the X-axis carriage 22. And a Y-axis carriage 23 that moves in the Y-axis direction perpendicular to the axis. The collimator lens 15 in the collimator unit 14, the bend mirror 16, and the condensing lens 18 in the processing head 17 are fixed to the Y-axis carriage 23 in a state where the optical axis has been adjusted in advance. Move in the axial direction. It is also possible to provide a Z-axis carriage that can move in the vertical direction with respect to the Y-axis carriage 23 and to provide the condenser lens 18 on the Z-axis carriage.

  The DDL processing apparatus according to the embodiment of the present invention irradiates the workpiece W with the laser beam LB having the smallest condensing diameter (minimum condensing diameter) condensed by the condensing lens 18 and coaxially assist gas. The X-axis carriage 22 and the Y-axis carriage 23 are moved while the melt is removed by spraying. Thereby, the DDL processing apparatus can cut the workpiece W. Examples of the workpiece W include various materials such as stainless steel, mild steel, and aluminum. The plate thickness of the workpiece W is, for example, about 0.1 mm to 50 mm.

  Next, the laser oscillator 11 will be described with reference to FIGS. 2A and 2B, the laser oscillator 11 includes a housing 60, the DDL module 10 housed in the housing 60 and connected to the transmission fiber 12, and the housing 60. A power supply unit 61 that is housed in the DDL module 10 and supplies power to the DDL module 10, a control module 62 that is housed in the housing 60 and controls the output of the DDL module 10, and the like are provided. An air conditioner 63 that adjusts the temperature and humidity in the housing 60 is installed outside the housing 60.

As shown in FIG. 3, the DDL module 10 superimposes and outputs laser beams of multiple wavelengths (λ ₁ , λ ₂ , λ ₃ ,..., Λ _n ). The DDL module 10 includes a plurality of laser diodes (hereinafter referred to as “LD”) 3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n (n is an integer of 4 or more), LD 3 ₁ , 3 ₂ , 3 ₃ , · · · _{3 n} to the fiber _{4 1,} 4 2, _{4 3,} is connected via a · · · _{4 n,} multiple wavelengths lambda _1, lambda _2, lambda _3, · · ·, to the laser beam of lambda _n A spectral beam combining unit 50 that performs spectral beam combining, and a condensing lens 54 that condenses the laser light from the spectral beam combining unit 50 and enters the transmission fiber 12 are provided.

Multiple _{LD3 1, 3 2, 3 3} , as a · · · _{3 n,} various kinds of semiconductor lasers can be employed. The combination of the types and numbers of LD3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n is not particularly limited, and can be appropriately selected according to the purpose of sheet metal processing. The wavelengths λ ₁ , λ ₂ , λ ₃ ,..., Λ _n of the LD 3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n are selected to be, for example, less than 1000 nm, or in the range of 800 nm to 990 nm. , In the range of 910 nm to 950 nm.

The laser beams having multiple wavelengths λ ₁ , λ ₂ , λ ₃ ,..., Λ _n are controlled by group (block) management for each wavelength band, for example. The output can be variably adjusted individually for each wavelength band. Further, the output of the entire wavelength band can be adjusted to have a desired absorption rate.

In the cutting process, LD3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n are simultaneously operated, and an appropriate assist gas such as oxygen or nitrogen is blown near the focal position. As a result, the laser beams of the respective wavelengths from the LD 3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n cooperate with each other and also with the assist gas such as oxygen to melt the workpiece at a high speed. Further, the molten work material is blown off by the assist gas, and the work is cut at a high speed.

The spectral beam combining unit 50 includes a fixing unit 51 that bundles and fixes the emission ends of the fibers 4 ₁ , 4 ₂ , 4 ₃ ,... 4 _n to form a fiber array 4, and fibers 4 ₁ , 4 ₂ , 4 _3. , a collimator lens 52 to the laser light into parallel light from · · · 4 _n, multiple wavelengths _{λ 1, λ 2, λ 3} , ···, a diffraction grating for matching an optical axis diffracting a laser beam of lambda _n (Diffraction grating) 53 and LD3 ₁ , 3 ₂ , 3 ₃ ,... 3 _n are provided with a partial reflection coupler 55 that constitutes a resonator together with a reflection surface provided at the rear end. In FIG. 3, as an example, the partial reflection coupler 55 is disposed between the collimator lens 52 and the condenser lens 54, but the arrangement position of the partial reflection coupler 55 is not limited to this. Specifically, the partial reflection coupler 55 is disposed at an angle of 45 degrees with respect to the optical axis, and a part of the reflected light includes an external mirror (not shown) and LD3 ₁ , 3 ₂ , 3 ₃ ,. .. The wavelength is fixed (locked) and stabilized by resonating a specific wavelength between 3 and _n .

Next, the optical parameters of the laser beam emitted from the transmission fiber 12 will be described with reference to FIG. The laser beam LB emitted from the transmission fiber 12 with a divergence angle θ is converted into parallel light having a beam diameter D by the collimator lens 15, condensed by the condenser lens 18, and becomes the minimum condensed diameter d at the focal length f. . When the wavelength λ of the laser beam and the spread angle α of the laser beam after the focal length f are satisfied, the minimum condensing diameter d, the Rayleigh length Zr, and the beam parameter product (BPP) are expressed by the following equations (1) to (3). It is expressed by the formula. However, _{W 0} is the minimum condensing ^radius, is M 2 = BPP × π / λ .

d = 2W ₀ = 1.27 × f × M ² × λ / D (1)
Zr = πd ² / 4M ² λ (2)
BPP = W ₀ × α (mm · mrad) (3)
Moreover, the cutting speed V [mm / s] of the workpiece W can be expressed by the following formula (4).

Here, P: laser power [W], A: absorption rate, E: melting energy or evaporation energy [J / mm ³ ], d: beam diameter [mm], and t: plate thickness [mm]. However, it is assumed that all energy is absorbed and the molten material is completely discharged by the assist gas.

  In the embodiment of the present invention, in order to achieve a good cutting quality in the cutting process of the workpiece W, the processing conditions of the DDL processing apparatus are as follows according to the thickness and the absorption rate of the workpiece W: To control.

  The wavelength of the multi-wavelength laser light is, for example, less than 1000 nm, may be about 800 nm to 900 nm, and may be about 910 nm to 950 nm.

  The BPP of the multi-wavelength laser light is, for example, about 4 mm · mrad to 25 mm · mrad, and may be about 7 mm · mrad to 20 mm · mrad. The laser power is, for example, about 1.2 kW to 4.0 kW, and preferably about 1.6 kW to 2.0 kW.

  The condensed diameter (beam waist) is, for example, about 150 μm to 370 μm, may be about 247 μm to 364 μm, and may be about 150 μm to 364 μm. The incident diameter to the condensing lens 18 forming the beam waist is 20 mm, for example, the condensing diameter d is about 300 μm to 364 μm, and the focal length is about 150 mm to 190 mm, for example.

  The thickness of the workpiece W is, for example, about 0.2 mm to 30 mm. When the workpiece W is a copper plate, the thickness is about 0.4 mm to 6 mm. When the workpiece W is a mild steel plate, the thickness is about 1 mm to 12 mm. When the workpiece W is an aluminum plate, the thickness is about 0.8 mm to 4 mm. In the case of a stainless steel plate, the thickness is about 0.3 mm to 12 mm.

  The cutting speed of the workpiece W is, for example, about 0.1 m / min to 60 m / min, and may be about 0.8 m / min to 18 m / min, and 14.6 mm / sec to 291.7 mm / sec. It may be a degree. The Joule heat per unit cutting length of the workpiece W is, for example, about 6.9 J / mm to 137.1 J / mm.

<First embodiment>
Next, as a first example, using a DDL processing apparatus according to an embodiment of the present invention, a CO ₂ laser processing apparatus and a Yb fiber laser processing apparatus as comparative examples, 1.0 mm, 1.6 mm, 2 Experimental results of high-speed cutting of mild steel with a thickness of 3 mm, 3.2 mm, 4.5 mm, 6 mm, 9 mm, 12 mm, and 16 mm will be described.

  For the purpose of high-speed cutting, in order to match conditions other than the type of laser, the output is 2 kW, and the processing conditions are controlled based on the absorption rate at an incident angle of 70 °. As shown in FIG. 5, the incident angle refers to an angle β formed by the center line of the laser beam LB and the perpendicular from the cutting front surface (cutting front) F of the workpiece W irradiated with the laser beam. For example, the absorptance of the material at an incident angle of 70 ° per collection diameter d is about 0.00042% / μm to 0.11% / μm.

  In the case of thermal processing by various processing devices, since the processing is performed while melting the material, the dissolved substance may adhere to the lower part of the material as a molten material (dross), particularly in the first implementation. In the example, as shown in FIG. 6, dross has not occurred, and the state where the cut surface is uniform and melted away and is not dented or wavy is defined as a good cutting quality. Control the processing conditions to obtain good cutting quality.

In the first embodiment, the BPP of laser light in the DDL processing apparatus is 10.3 mm · mrad, the BPP of laser light in the CO ₂ laser processing apparatus is 8 mm · mrad, and the BPP of laser light in the fiber laser processing apparatus is 2 3 mm · mrad.

  In each processing apparatus, the assist gas was oxygen, and in the DDL processing apparatus, the gas pressure of the assist gas was controlled at 0.05 MPa to 1.5 MPa. In the DDL processing apparatus, the condensing diameter d is controlled at a constant 364 μm, the Joule heat per unit cutting length of the workpiece W is controlled from 12.0 J / mm to 137.1 J / mm, and the cutting speed Was controlled at 14.6 mm / sec to 166.7 mm / sec.

Here, attention was paid to the cutting speed of the laser sheet metal processing, the absorption rate of the workpiece W, the condensing diameter, and the output. That is, attention was paid to the ratio (A / d) of Joule heat Ein (J / mm) per unit cutting length to the absorption rate A in the condensed diameter d. Further, for comparison of each processing apparatus, a cutting speed ratio with the value of the CO ₂ laser processing apparatus as 1.0 as a reference and an absorptivity A ratio (A / d ratio) at the condensed diameter d were calculated.

Table 1 shows the experimental results when 1.0 mm mild steel is cut. From Table 1, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 2 shows the experimental results when a 1.6 mm mild steel was cut. From Table 2, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 3 shows the experimental results when a 2.3 mm mild steel was cut. From Table 3, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 4 shows the experimental results when a 3.2 mm mild steel was cut. From Table 4, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 5 shows the experimental results when cutting 4.5 mm mild steel. From Table 5, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 6 shows the experimental results when cutting 6 mm mild steel. From Table 6, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

  Table 7 shows the experimental results when 9 mm mild steel was cut. From Table 7, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Moreover, it can be seen that the A / d of the DDL processing apparatus is larger than the CO2 laser processing apparatus and is more efficient.

Table 8 shows the experimental results when cutting 12 mm mild steel. From Table 8, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

Table 9 shows the experimental results when cutting 16 mm mild steel. From Table 9, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus and is efficient.

From the experimental results shown in Tables 1 to 9, the graph shown in FIG. 7 was created. As shown in FIG. 7, the DDL processing apparatus can cut faster than the CO ₂ laser processing apparatus under the processing conditions shown in Tables 1 to 9, and can also cut faster than the fiber laser processing apparatus. Can be evaluated. In addition, the result in stainless steel (thickness 1 mm) has a cutting speed ratio of 1.9, and as a general tendency, the results for the CO ₂ laser processing apparatus agree with the results for mild steel.

<Second embodiment>
Next, as a second example, similarly to the first example, using a DDL processing apparatus according to an embodiment of the present invention, a CO ₂ laser processing apparatus and a Yb fiber laser processing apparatus as comparative examples, The high-speed cutting of aluminum having a plate thickness of 1 mm, 2 mm, 3 mm, and 4 mm will be described. Also in the second example, for each processing apparatus, the processing conditions for obtaining good cutting quality shown in FIG. 6 were selected.

In the second embodiment, the BPP of laser light in the DDL processing apparatus is 10.3 mm · mrad, the BPP of laser light in the CO ₂ laser processing apparatus is 8 mm · mrad, and the BPP of laser light in the fiber laser processing apparatus is 2 3 mm · mrad.

  In each processing apparatus, the assist gas was nitrogen, and in the DDL processing apparatus, the gas pressure of the assist gas was controlled at 0.8 MPa to 1.5 MPa. In the DDL processing apparatus, the condensing diameter d is controlled at a constant 364 μm or 300 μm, and the Joule heat per unit cutting length of the workpiece W is controlled at 6.9 J / mm to 43.6 J / mm, In addition, the cutting speed of the workpiece W was controlled at 45.8 mm / sec to 291.7 mm / sec.

Table 10 shows the experimental results when cutting 1 mm of aluminum. From Table 10, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is smaller and better than the CO ₂ laser processing apparatus. Further, it can be seen that the cutting speed of the DDL processing apparatus is faster than that of the CO ₂ laser processing apparatus, and the processing can be performed at a high speed. It can also be seen that the A / d of the DDL processing apparatus is the largest and the efficiency is high.

  Table 11 shows the experimental results when cutting 2 mm of aluminum. From Table 11, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. It can also be seen that the A / d of the DDL processing apparatus is the largest and the efficiency is high.

  Table 12 shows the experimental results when cutting 3 mm of aluminum. From Table 12, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is the smallest and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is the fastest, and the processing was possible at a high speed. It can also be seen that the A / d of the DDL processing apparatus is the largest and the efficiency is high.

Table 13 shows the experimental results when cutting 4 mm of aluminum. In the experiment of Table 13, since the condensing diameter d of the DDL processing apparatus was changed from 247 μm to 300 μm, the values of A / d and A / d ratio also changed. From Table 13, it can be seen that the Joule heat per unit cutting length of the DDL processing apparatus is smaller than that of the CO ₂ laser processing apparatus and is equivalent to that of the fiber laser processing apparatus and good. Further, it can be seen that the cutting speed of the DDL processing apparatus is faster than that of the CO ₂ laser processing apparatus, which is equivalent to that of the fiber laser processing apparatus and can be processed at a high speed. Further, it can be seen that the A / d of the DDL processing apparatus is larger than that of the CO ₂ laser processing apparatus, is equivalent to the fiber laser processing apparatus, and is efficient.

From the experimental results shown in Tables 10 to 13, the graph of FIG. 8 was created. As shown in FIG. 8, it can be evaluated that the DDL processing apparatus can be cut faster than the CO ₂ laser processing apparatus under the above processing conditions. Further, even when compared with a fiber laser processing apparatus, it can be evaluated that cutting can be performed at high speed under the processing conditions shown in Tables 10 to 13 when the aluminum thickness is 2 mm or more and less than 4 mm.

<Third embodiment>
As a third embodiment, the relationship between the incident angle of the laser beam on the workpiece W and the absorption rate of the material will be described.

FIG. 9 (a) and FIG. 9 (b) show the calculation results of the absorption characteristics for iron and aluminum, respectively. For example, 10.6 μm is a wavelength used in a CO ₂ laser processing apparatus, 1080 nm is a wavelength used in a fiber laser processing apparatus, and a range of 910 nm to 950 nm is a wavelength used in a DDL processing apparatus. It is.

In FIGS. 9A and 9B, as shown in the first and second embodiments, when attention is paid to the absorption rate at which the incident angle of the laser beam on the cut front surface is 70 degrees, the iron and aluminum In any case, it can be seen that the absorptance with respect to the wavelength range of 910 nm to 950 nm is higher than the absorptance with respect to the wavelength of 10.6 μm. That is, it can be seen that the absorptance in the wavelength range generally used in the DDL processing apparatus is significantly higher than the absorptance in the wavelength range used in the CO ₂ laser processing apparatus.

Therefore, the wavelength of the multi-wavelength laser light in the DDL processing apparatus is selected to be less than 1000 nm, preferably in the range of 910 nm to 950 nm so as to effectively use the absorptivity characteristics in the wavelength range used in the DDL processing apparatus. By controlling other processing conditions, cutting can be performed at a higher speed than the CO ₂ laser processing apparatus.

As described above, according to the embodiment of the present invention, the CO ₂ laser processing apparatus is controlled by controlling the processing conditions such as the cutting speed of the DDL processing apparatus according to the absorption rate and thickness of the workpiece W. The incident angle can be made smaller than that, and the melting effect of the specific cutting material of the thermal cutting in the laser cutting process can be enhanced as compared with the CO ₂ laser processing apparatus. Further, depending on the material and thickness of the workpiece W, it is possible to process the workpiece W more efficiently and at a higher speed than the fiber laser processing apparatus because of the relationship between the absorptivity and thickness of the workpiece W and the light collection diameter.

(Other embodiments)
Although the present invention has been described with reference to embodiments, it should not be understood that the description and drawings that form part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. It goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 10 ... DDL module 11 ... Laser oscillator 12 ... Transmission fiber (process fiber)
DESCRIPTION OF SYMBOLS 13 ... Laser processing machine 14 ... Collimator unit 15 ... Collimator lens 16 ... Bend mirror 17 ... Processing head 18 ... Condensing lens 21 ... Processing table 22 ... X-axis carriage 23 ... Y-axis carriage 3 ₁ , 3 ₂ , 3 ₃ ,. .... 3 _n Laser diode (LD)
4 ₁ , 4 ₂ , 4 ₃ ,... 4 _n ... Fiber 50... Spectral beam coupling part 51... Fixed part 52.
53 ... Diffraction grating (optical element)
54 ... Condensing lens (optical element)
55 ... Partially reflective coupler 60 ... Housing 61 ... Power source 62 ... Control module 63 ... Air conditioning equipment

Claims (8)

A laser resonator that oscillates multi-wavelength laser light;
A transmission fiber for transmitting multi-wavelength laser light oscillated by the laser resonator;
A laser processing machine for condensing multi-wavelength laser light transmitted by the transmission fiber and processing a workpiece;
Based on the thickness and absorption rate of the workpiece,
The wavelength of the multi-wavelength laser light is less than 1000 nm,
The beam parameter product of the multi-wavelength laser light is 4 mm · mrad to 25 mm · mrad, and the cutting speed of the workpiece is 0.1 m / min to 60 m / min.
A direct diode laser processing apparatus, characterized in that   The direct diode laser processing apparatus according to claim 1, wherein the pressure of the assist gas sprayed on the workpiece is controlled to 0.05 MPa to 1.5 MPa.   3. The direct diode laser processing apparatus according to claim 1, wherein a condensing diameter of the multi-wavelength laser light is controlled to 247 μm to 364 μm.   The direct diode laser processing according to any one of claims 1 to 3, wherein a Joule heat per unit cutting length of the workpiece is controlled to 6.9 J / mm to 137.1 J / mm. apparatus.   The ratio of the absorptivity at an incident angle of 70 ° with respect to the condensed diameter of the multi-wavelength laser light is controlled to 0.00042% / μm to 0.11% / μm. The direct diode laser processing apparatus according to claim 1. The workpiece is mild steel having a thickness of 1 mm to 16 mm,
The pressure of the assist gas sprayed on the workpiece is 0.05 MPa to 1.5 MPa,
The Joule heat per unit cutting length of the workpiece is controlled to 12.0 J / mm to 137.1 J / mm, and the cutting speed of the workpiece is controlled from 14.6 mm / sec to 166.7 mm / sec. The direct diode laser processing apparatus according to claim 1, wherein: The workpiece is aluminum having a thickness of 1 mm to 4 mm,
The pressure of the assist gas sprayed on the workpiece is 0.8 MPa to 1.5 MPa,
The Joule heat per unit cutting length of the workpiece is controlled to 6.9 J / mm to 43.6 J / mm, and the cutting speed of the workpiece is controlled to 45.8 mm / sec to 291.7 mm / sec. The direct diode laser processing apparatus according to claim 1, wherein:   A sheet metal processing method, comprising: cutting a sheet metal using the direct diode laser processing apparatus according to claim 1.