JPH0371235B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing device for dulling the surface of a rolling roll or the like by irradiating a mechanically pulsed laser beam.

[Conventional technology]

In recent years, the surface of a rolling roll is irradiated with a pulsed laser beam to form countless irregularities on the roll surface, and by using a roll on which the irregularities are formed during the temper rolling process after annealing the cold rolled steel sheet,
A method has been adopted in which the uneven pattern on the roll surface is transferred to the surface of the steel plate. This method using a laser beam differs from the uneven pattern formed by the conventional shot blasting method using steel balls, in that the size of each unevenness is uniform over the entire surface of the roll, and the adjacent unevenness is Since the pitch is constant, it has the characteristic that the sharpness of the steel plate surface treated by this method after painting is improved.

An example of such a conventional processing device using a laser beam will be explained with reference to FIGS. 6 and 7.

In the figure, reference numeral 1 denotes a rolling roll as a workpiece, which is rotatably supported by support stands 2 and 3. 4 is a drive section, and a power transmission section 5
Apply rotational force to the support base 3 through the rolling roll 1
Rotate. 6 is a base on which the above-mentioned parts 2 to 5 are installed.

Reference numeral 7 denotes a laser oscillator, which is attached to a cart 10 that is movable on rails 9 provided on a base 8. The rail 9 is provided parallel to the axis of the mill roll 1 so that the carriage 10 can move parallel to the surface of the mill roll. Reference numeral 11 denotes a transmission duct, which serves as a path for guiding the laser beam emitted from the laser oscillator 7 to a condensing lens 12. A reflecting mirror 13 is provided inside the bent portion of the duct 11 to reflect the laser beam. let me,
The surface of the rolling roll 1 is irradiated through a condensing lens 12.

The laser beam converged by the condenser lens 12 passes through a mechanical chopper 14, which is a beam chopping means, through a through hole (not shown) provided at the tip of the torch 16 to which the condenser lens 12 is attached. It is designed to focus on the rolling roll 1.
The disk-shaped mechanical chopper 14 has slits arranged around its circumference through which the laser beam can pass, and this disk is rotated at high speed using a separate means to pulse the laser beam and irradiate it onto the rolling roll 1. By doing so, countless small recesses are formed on the surface of the roll 1 at a constant pitch.
Reference numeral 15 denotes a gas nozzle serving as an assist gas spraying means, the tip of which is provided so as to open immediately adjacent to the outer peripheral end of the mechanical chopper 14, and assist gas (for example, O ₂ ) is sprayed from the gas nozzle onto the roll 1 by the laser. By spraying toward the beam focal position, the minute recesses to be drilled are formed to have a uniform shape and a required depth.

[Problem that the invention seeks to solve]

However, with such conventional processing equipment, the assist gas cannot be sprayed perpendicularly to the surface of the workpiece, and the tip of the gas nozzle is close to the mechanical chopper, furthermore, the chopper cannot be focused on the beam. Since it is configured so that it cannot be located at the light spot, (1) the assist gas is blown in an oblique direction, distorting the shape of the hole formed by the laser;

(2) The flow of the assist gas is disturbed by the wind pressure generated by the high-speed rotation of the tipper, and it does not act effectively on the surface of the workpiece.

(3) The mutual positional relationship between the tipper and the gas nozzle greatly influences the shape of the hole formed by the laser, but its adjustment is delicate and takes time.

(4) The position where the chopper cuts the beam must be at a position where the beam is not sufficiently focused, and as a result, the beam passing through the chopper does not form a rectangular wave, resulting in poor processing efficiency.

Various problems arose.

This invention was made in view of these conventional problems, and solves the above problems by providing a beam chopping means on the side opposite to the workpiece with respect to the condensing lens. It is intended to.

[Means for solving problems]

In order to solve the above problems, the laser processing apparatus of the present invention includes a beam chopping device provided on the side opposite to the workpiece with respect to the condensing lens provided on the torch, and an assist gas spraying device. is provided so as to be sprayed onto the workpiece along the optical axis of a condensing lens provided on the torch, condensing lenses are disposed before and after the beam chopping device, and condensing lenses are provided before and after the beam chopping device. The lens is provided with a condensing lens position adjustment device that adjusts the position in the optical axis direction and the position perpendicular to the optical axis, and the beam chopping device is further provided with a beam chopper position adjustment device that adjusts the position in the optical axis direction. has been established.

[Effect]

According to this invention, since the beam chopping means is provided on the side opposite to the workpiece with respect to the condensing lens provided on the torch, the laser beam emitted from the laser oscillator is The beam is pulsed before entering the condensing lens, and is irradiated onto the workpiece through the torch.The condensing lenses placed before and after the beam chopping means are pulsed in the direction of the optical axis and in the direction perpendicular to this. Since the position can be adjusted and the position of the beam chopping device can also be adjusted in the optical axis direction, the focusing position of the laser beam and the beam stepping position can be precisely adjusted, and the focusing position provided on the torch can also be adjusted. The laser beam incident on the optical lens can also be a parallel beam. In addition, since the flow of assist gas is not affected by the rotation of the beam chopping device, the shape of the concave hole formed in the workpiece is stable, and the beam chopping device is rotated at high speed to increase processing efficiency. It becomes possible to do so.

〔Example〕

Next, a description will be given based on the embodiment shown in FIGS. 1 to 5. FIG. 1 is a schematic explanatory diagram showing the entire laser processing apparatus, where 1 is a rolling roll for temper rolling as a workpiece, 7 is a laser oscillator,
Reference numeral 12 is a condenser lens that focuses the laser beam on the circumferential surface of the rolling roll, and reference numeral 13 is a reflecting mirror, both of which are the same as in the conventional example.

Between the reflecting mirror 13 and the condensing lens 12,
A chopper disk 24 forming a beam chopping device is arranged with a peripheral slit facing the optical axis Y of the laser beam, and in front and behind this chopper disk 24,
Condenser lenses 31 and 32 are arranged corresponding to the optical axis Y. The condensing lens 31 has a focal length l ₁ , is emitted from the laser oscillator 7, and is reflected by the reflecting mirror 13.
focuses a laser beam whose direction has been changed by 90 degrees.
The condenser lens 32 has a focal length of l ₂ and is located along the same optical axis Y at a distance of approximately l ₁ +l ₂ from the condenser lens 31.
It is arranged so that. The laser beam focused by the condenser lens 31 becomes a parallel beam by the condenser lens 32, enters the condenser lens 12 provided on the torch 26, is condensed again, and passes through the through hole 26a at the tip of the torch 26. The beam is focused and projected onto the surface of the rolling roll 1, which is the workpiece.

A plurality of slits are arranged at equal intervals in the circumferential direction on the outer circumference of the chopper disk 24, and the motor M
It rotates at high speed by the power transmitted from the motor through a known transmission mechanism. This tipper disc 24 is located approximately midway between the condenser lens 31 and the condenser lens 32.
It is installed at the position where the beam most converges, and repeats passing and blocking of the laser beam in extremely short cycles, making the laser beam pulse-like.

25 is an assist gas supply port such as O ₂ provided in the torch 26, and is connected to the condensing lenses 31, 12,
32 and the center of the through hole 26a are arranged in a straight line, and the gas entering the torch 26 is directed from the through hole 26a onto the extension of the optical axis Y on the surface of the rolling roll 1. is sprayed towards.

Since the tipper disk 24 is provided on the side opposite to the rolling roll 1 with respect to the condensing lens 12 provided on the torch 26, the laser beam emitted from the laser oscillator 7 is provided on the torch 26. The light is pulsed before entering the condensing lens 12,
The rolling roll is irradiated through the torch 26. Further, the assist gas is applied to the optical axis Y of the condenser lens 12.
The blowing direction of the assist gas and the direction of the laser beam irradiation are the same. 26a
are separated from each other with the condensing lens 12 interposed between them, so the wind pressure generated by the high-speed rotation of the tipper disk 24 does not affect the gas blowing, so the hole shape formed on the surface of the rolling roll 1 is A precise uneven pattern is created without distortion. Also Chiyotsupa disk 24
Since the position can be located at the focal point of the beam, the formed pulse beam becomes a precise rectangular wave, improving processing efficiency.

The functions required in such a device are as follows.

(1) The optical axes of the condensing lenses 31 and 32 can be precisely set. This allows the laser beam oscillated from the oscillator 7 to be accurately directed to the condenser lens 12 without shifting the optical axis Y by the condenser lenses 31 and 32.
and functions necessary for making the rolling roll 1 reach a predetermined position.

(2) It is possible to accurately measure the distance l ₁ between the condensing lens 31 and the position where the beam exiting the condensing lens 31 is condensed, and to accurately position the tipper disk 24 at this position. This is because, as will be described later, the beam pulsed by the chopper disk 24 becomes a rectangular wave as the chopper disk 24 is positioned at a location where the beam diameter is smaller, and the processing efficiency improves. Furthermore, in general, the beam oscillated from the oscillator 7 is not a parallel ray, but has a certain divergence angle θ as shown in Figure 1, but this θ varies depending on the output of the same oscillator and the difference in the conditions at that time. When θ changes, the l ₁ also changes, so it is necessary to adjust the position of the tipper disc 24 each time machining is performed. For this purpose, l ₁ and l ₂ can be measured efficiently and easily.
It is necessary to have a structure that allows adjustment of the position of the tipping disc 24. In particular, CO ₂ lasers require special equipment because the beam is invisible.

(3) The distance L between the condensing lenses 31 and 32 can be accurately adjusted so that the beam emitted from the condensing lens 32 becomes a completely parallel beam.This is because, for the reason mentioned above, when θ changes, l ₁ changes. If the position of the condensing lens 32 is fixed, the parallelism of the beam exiting the same lens will change, and as a result, the focal position la of the beam exiting the condensing lens 12 will change, so θ Of course, if the angle changes, it becomes necessary to adjust the position of the condensing lens 12, but if the parallelism of the beam incident on the condensing lens 12 worsens, the aberration caused by the condensing lens 12 increases, and the rolling roll 1 This is because the diameter of the irradiated spot is not sufficiently small, resulting in a decrease in processing efficiency.

(4) Apply gold plating to the chiyotsupa disk 24. This is because the closer the tipper position is to the condensing point, the higher the energy density of the beam irradiated to the tipper disk 24 becomes, increasing the risk of melting and burning out the tipper disk 24. Therefore, the reflectance of the laser beam decreases. Good results can be obtained by plating the surface of the disc with the highest quality gold or a similar metal.

In order to provide such a function, this device specifically employs the configuration shown in FIGS. 2 and 3 for both condenser lenses 31 and 32 and the chopper disk 24 shown in FIG. 1. That is, the condenser lenses 31 and 32 are individually provided with condenser lens position adjustment devices A and B that adjust the positions of both lenses 31 and 32 in the optical axis Y direction and in the horizontal direction perpendicular thereto. In addition, the Chiyotsupa disk 24 has
A beam chopper position adjustment device C is provided to adjust the position of the beam chopper in the optical axis Y direction.

Each of these adjusting devices A, B, and C will be explained next. First, a description will be given of a condensing lens position adjusting device B that adjusts the position of the condensing lens 32 in the optical axis Y direction and in the horizontal direction perpendicular thereto.

51 is a collimator lens mount, and a slide rail 5 is installed along the longitudinal direction of the upper surface thereof.
2, a vertical slide table 53 is slidably installed,
A slide rail 52 is placed on this vertical slide base 53.
A horizontal slide table 54 is installed so as to be slidable in the horizontal direction perpendicular to the horizontal direction, and a support frame 55 is provided on the horizontal slide table 54 so as to be movable forward and backward in the direction in which the slide rail 52 extends. A holder 56 is engaged with the support frame 55 so as to be movable up and down.
The condenser lens 32 is supported within the protective cover 57.

Between the pedestal 51 and the vertical slide pedestal 53,
A vertical slide position adjuster 41 with a micrometer is arranged to slide the vertical slide stand 53 along the slide rail 52, and a vertical slide position adjuster 41 with a micrometer is arranged between the vertical slide stand 53 and the horizontal slide stand 54. A lateral slide position adjuster 42 with a micrometer is disposed for sliding in the lateral direction, and between the lateral slide table 54 and the support frame 55, the angle of the support frame 55 is adjusted and the condenser lens 32
Adjust so that the axis line of and the optical axis Y match,
4 angular position adjusters 43 with micrometers
A height position adjuster 44 with a micrometer is arranged between the support frame 55 and the holder 56 to adjust the height position of the holder 56. Each of these members 51 to 57 and each regulator 41
- 44 constitute a condensing lens position adjustment device B, and by operating each adjuster 41 - 44,
The position, height position, and inclination angle of the condenser lens 32 in the optical axis Y direction and in the horizontal direction perpendicular thereto are adjusted.

The condensing lens position adjustment device A for the other condensing lens 31 has the same structure as the condensing lens B and is installed opposite to the condensing lens B, so the same part is shown in the same figure. The detailed explanation will be omitted with the symbol . However, both A and B
In both cases, it goes without saying that the frame 51 and the slide rail 52 are the same member. Therefore,
This condenser lens position adjustment device B also adjusts the position, height, and inclination angle of the condenser lens 31 in the optical axis Y direction and in the horizontal direction perpendicular thereto.

With the above condensing lens position adjustment devices A and B,
The above functions (1), (2), and (3) are satisfied.

Next, a beam chopper position adjustment device C for adjusting the position of the chopper disk 24 in the optical axis Y direction is installed.
This will be explained based on FIG. The chopper disk 24 has a shape in which a large number of slits are provided at equal intervals around the circumference of the disk, and these slits are positioned near the convergence point of the laser beam condensed by the condenser lens 31. By rotating the chopper disk 24 at high speed, the laser beam is converted into a pulse beam. This tipper disk 24 is plated with gold and satisfies the above-mentioned function (4).

The beam chopper position adjustment device C includes a chopper mount 61, a slide plate 62 installed on the chopper mount 61 so as to be able to move forward and backward in a direction parallel to the optical axis Y.
A support frame 63 fixed on the slide plate 62 is installed between the pedestal 61 and the slide plate 62, and the slide plate 62 is moved parallel to the optical axis Y, thereby causing the tipper disk 24 to tip the laser beam. It consists of a slide position adjuster 64 with a micrometer whose position can be freely controlled. The tipper disk 24 is rotatably supported on the support frame 63, and the output shaft 65 of the motor M fixed on the pedestal 61 and the rotating shaft 6 of the tipper disk 24 are connected to the support frame 63.
A transmission belt 67 is spanned between the motor M and the tipper disk 24, so that the tipper disc 24 is rotated at high speed by the motor M.

Note that the collimator lens mount 51 and the tipper mount 61 are separated from each other so that vibrations caused by the rotation of the tipper disk 24 are not transmitted to the condensing lenses 31 and 32.

Next, a device for measuring the focal point position of a laser beam will be explained using FIGS. 4 and 5.

In FIG. 4, reference numeral 71 denotes a slide stand, on which is erected a pillar 74 having a base end of a metal plate 72 having a thin protrusion at its end fixed by a pin 73.
When measuring the focal point of the laser beam, this is placed on a slide rail 52 on a collimator lens stand 51, as shown in FIG. The slide stand 71 is adapted to move on the slide rail 52 in the direction of the optical axis of the laser beam. Note that in FIG. 5, only one angular position adjuster 43 is shown in each of the condenser lens position adjustment devices A and B.

Next, a laser beam is passed through the collimator lens, and the metal plate 72 is moved while moving the slide table 71 in the optical axis direction while applying the beam to the protrusion of the metal plate 72.
The point (light condensation point) where the sparks generated on 2 are the largest is found, and this position is read by the scale 75 attached to the pedestal 51. The tipper disk 24 is positioned at this focal point position by adjusting the position adjuster 64, thereby also satisfying the function (2). When the measurement of the focal point position is completed, the slide stand 71 is usually removed.

In this embodiment, an example was described in which the present invention was applied to an apparatus that performs laser dulling on a mill roll 1 for temper rolling as a workpiece.
It goes without saying that the apparatus of the present invention can be applied to other workpieces than the rolling roll 1.

〔Effect of the invention〕

According to the present invention, the following effects can be obtained. In other words, (1) Since the Chiyotsupa disk is located in a different part from the assist gas supply part, the flow of the assist gas is not affected by the rotation of the Chiyotupa disk, so the shape of the hollow hole to be machined is stable. In particular, it becomes possible to rotate the chopper disk at high speed in order to increase processing efficiency.

(2) Since the assist gas is blown along the optical axis of the condensing lens, the countless concave holes regularly formed on the surface of the workpiece are uniformly formed without distortion.

(3) Adjustment of the position and angle of the condensing lens and adjustment of the tipper position, which are essential for improving processing efficiency, can be performed accurately and efficiently.

[Brief explanation of drawings]

Fig. 1 is an overall schematic explanatory diagram showing an embodiment of the present invention, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is a front view of Fig. 2, and Fig. 4 is a collection of laser beams. 5 is a perspective view of the mechanism shown in FIG. 4 applied to the device shown in FIG. 3, FIG. 6 is a plan view of the conventional example, and FIG. 7 is a perspective view of the device shown in FIG. 6. It is an enlarged view of the main part. A, B... Converging lens position adjustment device, C... Beam chopper position adjustment device, M... Motor, 1... Roll roll (workpiece), 7... Laser oscillator, 12,
31, 32... Condensing lens, 24... Chiyotsupa disk,
25...assist gas supply port, 26...torch, 41
...Vertical slide position adjuster, 42...Horizontal slide position adjuster, 43...Angle position adjuster, 44...Height position adjuster, 51...Collimator lens mount, 52...Slide rail, 53...Vertical slide base, 54...Horizontal Slide stand, 55... Support frame, 56... Holder, 57...
Protective cover, 61... Chiyotsupa frame, 62... Slide plate, 63... Support frame, 64... Position adjuster, 71...
Slide base, 72...metal plate, 73...pin.

Claims (1)

[Claims] 1. In a laser processing device equipped with a condensing lens provided on a torch, a beam chopping device, and an assist gas blowing means in order to process a workpiece by irradiating a laser beam in a pulsed manner, the beam chopping device A pinging device is provided on a side opposite to the workpiece with respect to the condenser lens, and the assist gas spraying means is configured to spray the workpiece along the optical axis of the condenser lens provided on the torch. and a condensing lens is provided before and after the beam chopping device, and a condensing lens for adjusting the position in the optical axis direction and the position perpendicular to the optical axis of the condensing lens before and after the beam chopping device. What is claimed is: 1. A laser processing device comprising: a lens position adjustment device; and a beam chopper position adjustment device for adjusting the position of the beam chopping device in the optical axis direction.