JP3999999B2 - Laser surface processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser surface processing apparatus for drilling or surface-treating with a fiber laser beam.
The laser surface processing apparatus of the present invention is used for drilling a thin metal plate (foil), a ceramic plate or the like, and for controlling the magnetic domain of an electromagnetic steel sheet and other surface treatments.
[0002]
[Prior art]
Lasers such as a CO2 laser and a YAG laser are widely used for drilling or surface treatment of metals and ceramics. Since these lasers provide high output, deep holes can be machined at once.
[0003]
However, the higher the output, the more easily plasma is generated. Since the generated plasma absorbs the laser beam, the thermal energy supplied to the processing portion decreases, and the processing efficiency decreases. Further, since a large amount of spatter is generated and the processing nozzle becomes dirty, it is necessary to clean or replace the processing nozzle. Furthermore, there is a problem in terms of processing quality in that the periphery of the hole generated by drilling or surface treatment is raised or returned, the function of the product is lowered, and the appearance is impaired.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a laser surface processing apparatus capable of drilling or surface-treating with high processing efficiency and processing quality.
[0005]
[Means for Solving the Problems]
The laser surface processing apparatus according to the present invention includes a plurality of fiber laser oscillation devices and an output control device for controlling on / off of the laser light output, and a plurality of active optical fibers or active lights corresponding to the plurality of fiber laser oscillation devices. A laser surface processing device that drills or surface-treats the surface of a magnetic steel sheet or continuous casting roll that moves relative to a plurality of processing nozzles connected to the output ends of a plurality of passive optical fibers connected to the fiber at a constant speed. The processing nozzles are arranged two-dimensionally and aligned, and laser beams are sequentially and sequentially emitted from the same number of processing nozzles as the number of times of irradiation to the same processing unit aligned in the direction of movement. Then, the output is performed so that processing is performed at equal intervals in the moving direction of the surface of the electromagnetic steel sheet or continuous casting roll, and the same processed part is irradiated with laser light a plurality of times. By controlling the injection current of a plurality of semiconductor lasers for exciting the fiber laser by control unit controls the irradiation period, and the subsequent processing nozzle is a depth that is processed by the laser beam from the preceding processing nozzle focal point Lower the position of and irradiate.
[0006]
The laser surface processing apparatus configured as described above irradiates the same processed portion with a plurality of times of laser light, so that the output of one irradiation can be low. As a result, generation of plasma and sputtering can be suppressed. Further, there is no swell or return around the hole produced by drilling or surface treatment. In addition, although the frequency | count of irradiation changes with process conditions, it is about 2 to several times.
[0007]
In the laser surface processing apparatus, the rear optical fiber may be disposed by lowering the position of the output end of the rear optical fiber by the depth processed by the laser light from the front optical fiber. Thereby, the hole bottom part in the middle of processing can be irradiated with high energy density, and processing efficiency can be improved.
[0008]
In the laser surface processing apparatus, an active optical fiber or a passive optical fiber having a rectangular core cross section is used, or laser beams output from an active optical fiber or a passive optical fiber having a circular core cross section are collected in an elliptical shape. A condensing optical system that emits light may be used. Thereby, the number of optical fibers in surface processing can be significantly reduced compared with the case where an optical fiber with a circular core shape is used. When condensing in an elliptical shape, a condensing optical system that combines a convex lens and a cylindrical lens is used.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of the present invention and is a schematic diagram of a laser surface processing apparatus.
[0010]
The laser surface processing apparatus mainly includes a plurality of fiber laser oscillation devices 10, an output control device 16, and a processing nozzle group 20.
[0011]
1 illustrates eight fiber laser oscillators 10 in FIG. 1, but several to several tens of thousands are used depending on processing conditions. The fiber laser oscillation device 10 includes a semiconductor laser oscillator 14 as an excitation device. As the semiconductor laser oscillator 14, for example, a Ga-As semiconductor laser oscillator can be used. When the active optical fiber (laser oscillation optical fiber) 12 is irradiated with excitation laser light (wavelength: about 0.8 μm) from the semiconductor laser oscillator 14, laser light (wavelength: about 1.06 μm) oscillates in the active optical fiber 12. . The output of the active optical fiber 12 is 5 W, for example, and the core diameter is 50 μm. A passive optical fiber (power transmission optical fiber) may be connected to the output end face by fusion, and the laser light may be transmitted to the processing nozzle 25 by the passive optical fiber.
[0012]
The output control device 16 includes a control computer and is connected to the semiconductor laser oscillator 14 via an interface (not shown). The output control device 16 controls the injection current of the semiconductor laser oscillator for each fiber laser oscillation device 10. When the injection current exceeds the threshold value, the fiber laser oscillation device 10 oscillates, and when the injection current becomes below, the oscillation is stopped and the laser beam output is controlled on / off. In the optical fiber rows 21, 22, and 23, the irradiation frequency is set in advance according to the processing conditions.
[0013]
The processing nozzle group 20 is composed of three rows of processing nozzle rows 21, 22, and 23 arranged at an interval d in the moving direction (vertical direction) of the workpiece 1. In the processing nozzle rows 21, 22, and 23, eight processing nozzles 25 are arranged in a direction perpendicular to the moving direction (lateral direction). The processing nozzles 21, 22, and 23 hold the tip of the optical fiber 12 with the optical axis aligned. For the sake of simplicity, FIG. 1 shows the connection of the optical fiber 12 only to the first processing nozzle row 21. The output end of the optical fiber 12 is arranged facing the position of the processing part. The vertical interval between the processed parts is dL.
[0014]
In the laser surface processing apparatus configured as described above, the laser beam is turned on / off at a preset frequency while feeding the workpiece 1 at a constant speed V. As shown in the time chart of FIG. 2, the first machining nozzle rows 21, 22, and 23 are all turned on / off at the same frequency V / dL. The second machining nozzle row 22 is turned on / off with a delay of d / V from the first machining nozzle row 21 and the third machining nozzle row 23 is delayed with a delay of 2 d / V. Accordingly, one processed part is irradiated three times. In the second machining nozzle row 22, irradiation is performed by lowering the position of the condensing point by the depth machined by the first machining nozzle row 21. Similarly, the third processing nozzle row 23 is irradiated with the focal point lowered. The power output from each optical fiber 12 has a magnitude of about 1/3 or less of the case where irradiation is performed once.
[0015]
When the optical fibers are arranged one-dimensionally, they are arranged in a line at a predetermined interval along the moving direction of the workpiece. If the output end of the optical fiber cannot be placed close to the workpiece surface due to heat or the like, the output end is separated from the workpiece surface, and a condenser lens is arranged between the output end and the workpiece.
[0016]
【Example】
Example 1
For magnetic domain control of magnetic steel sheets with heat resistance by machining holes with a depth of 15μm in the plate width direction and a diameter of 0.1mm on both sides of the steel sheet at a pitch of dL = 3mm in the rolling direction on an electromagnetic steel sheet (plate width 60mm) The present invention is applied.
[0017]
In the embodiment, 600 optical fibers having a core diameter of 50 μm are arranged in three rows with a distance d = 3 mm in the longitudinal direction at 600 per processing nozzle. The moving speed V of the steel plate was 180 mpm (3 m / s = 3,000 mm / s). The output frequency of the optical fiber was set to 1 kHz from the speed V and the processing interval dL. Under the above processing conditions, the required energy per optical fiber is about 5 mJ. As a result, the peak output per optical fiber is 1000 W and irradiation is performed for 5 μs, so the average output per optical fiber during operation is 5 W.
[0018]
By irradiating with laser divided into 3 times, high-quality hole processing without fluctuating and melting protrusions that occur when processing to the target dimensions of 15μm in depth and 0.1mm in diameter on the surface of magnetic steel sheet. Was realized. As a result, a magnetic domain control electrical steel sheet having heat resistance that does not require post-treatment such as brushing was obtained.
[0019]
In this embodiment, a fiber core having a circular cross-sectional shape is used. However, an optical fiber having a rectangular cross section or laser light output from a circular cross section may be condensed into an elliptical shape. As a result, the number of fibers in the plate width direction can be greatly reduced.
[0020]
(Example 2)
By continuously drilling holes with a depth of 80 μm and a diameter of 0.18 mm on the surface of a continuous casting roll (diameter: 2 m, width: 1 m) at a vertical and horizontal dL = 0.25 mm pitch, there is no continuous cracking or unevenness on the continuously cast steel plate surface. The present invention is applied to the production of cast steel sheets.
[0021]
In the embodiment, one optical fiber having a core diameter of 100 μm is arranged in one row per processing nozzle, and three rows are arranged in the longitudinal direction at an interval d = 0.25 mm. The rotation speed V of the roll is 12 rpm (linear speed = 1.26 m / s), and the machining nozzle moves at a speed of 50 μm / s (= 50 × 10 ⁻⁶ m / s) in parallel with the body length of the roll. The output frequency of the optical fiber was 5040 Hz from the speed V and the processing interval dL. Under the above processing conditions, the required energy per optical fiber is about 25 mJ. As a result, the peak output per optical fiber is 1000 W and irradiation is performed for 5 μs, so the average output per optical fiber during operation is 126 W. It takes about 20,000 s (= 5 hours 33 minutes 20 seconds) to process the entire roll surface with a pitch of 0.25 mm.
[0022]
By irradiating with laser divided into three times, high-quality hole processing with a small variation in the target dimensions of 80 μm depth and diameter of 0.18 mm can be made on the roll surface. Drilling without melting protrusions was realized. Thereby, since post-processing such as brushing is not required, the production efficiency is improved and a high-quality steel sheet can be manufactured.
[0023]
(Example 3)
Electromagnetic steel with heat resistance by machining a melt-resolidified layer with a depth of 0.01mm in the plate width direction and a width of 0.05mm on both sides of the steel plate (dL = 3mm pitch) in the rolling direction. The present invention is applied to the magnetic domain control of a steel plate.
[0024]
In the embodiment, 150 optical fibers each having a core diameter of 50 μm × 200 μm are arranged in 150 rows per row of processing nozzles, and three rows are arranged at a distance d of 1 mm in the longitudinal direction. The moving speed V of the steel plate was 180 mpm (3 m / s = 3,000 mm / s). The output frequency of the optical fiber was set to 1 kHz from the speed V and the processing interval dL. Under the above processing conditions, the required energy per optical fiber is about 5 mJ. As a result, the peak output per optical fiber is 1000 W and irradiation is performed for 5 μs, so the average output per optical fiber during operation is 5 W.
[0025]
By irradiating with laser divided into three times, the surface of the magnetic steel sheet has a depth of 10 μm, a width of 0.05 mm, and a length of 0.2 mm. High quality melt resolidification layer processing was realized. As a result, a magnetic domain control electrical steel sheet having heat resistance that does not require post-treatment such as brushing was obtained.
[0026]
In this embodiment, an optical fiber having a rectangular fiber core cross-sectional shape is used, but laser light output from a circular cross-section may be condensed into an elliptical shape and used.
[0027]
【The invention's effect】
In the laser surface processing apparatus according to the present invention, the same processed portion is irradiated with laser light in a plurality of times, so that the output of one irradiation can be reduced. As a result, generation of plasma and sputtering can be suppressed. Further, there is no swell or return around the hole generated by drilling or surface treatment. As a result, surface processing can be performed with high processing efficiency and processing quality.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a laser surface processing apparatus according to the present invention.
FIG. 2 is a time chart of laser beam irradiation of a machining nozzle row in the apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Workpiece 19 Fiber laser oscillation apparatus 12 Optical fiber 14 Semiconductor laser oscillator 16 Output control apparatus 20 Processing nozzle group 21, 22, 23 Processing nozzle row 25 Processing nozzle dL Processing interval d Processing nozzle row interval

Claims (3)

A plurality of active optical fibers or a plurality of passive optical fibers connected to the active optical fibers, each having a plurality of fiber laser oscillating devices and an output control device for controlling on / off of the laser light output a laser surface processing apparatus for drilling or surface treated electrical steel sheet or the surface of the continuous casting rolls move relatively at a constant velocity for a plurality of working nozzles having an output connected to the processing nozzle is a two-dimensional Are aligned and arranged in the direction of movement, and the laser beam is sequentially and periodically emitted from the same number of processing nozzles as the number of times of irradiation to the same processing portion, and the magnetic steel sheet or continuous casting roll Processing is performed at equal intervals in the moving direction of the surface, and the fiber laser is excited by the output control device so that the same processed part is irradiated with laser light multiple times. By controlling the injection current of a plurality of the semiconductor lasers to control the irradiation period to, and subsequent processing nozzle irradiates lower the position of only the focal point depth processed by a laser beam from the preceding processing nozzle Laser surface processing apparatus characterized by the above.   The laser surface processing apparatus according to claim 1, wherein the active optical fiber or the passive optical fiber has a rectangular core cross-sectional shape.   The laser surface processing apparatus according to claim 1, further comprising a condensing optical system that condenses laser light output from an active optical fiber or a passive optical fiber having a circular core cross-sectional shape in an elliptical shape.

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