JP2000280086A - Laser processing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly treat laser beams to be reflected by an aperture. SOLUTION: A hollow cover 13, whose inner faus are parallel, formed of a high laser beam 2 absorptive material, such as carbon, is arranged on an incident side of the laser beam 2 of an aperture 10 in a way that the inner faces are parallel to the laser beam 2. Then, all reflection beams 2b reflected by a side face 10b of the aperture 10 are incident on the inner face of the cover 13, and converted into the heat. Also, the cover 13 is cooled by a cooling means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam machine in which an aperture provided with a window limits a laser beam emitted from a laser oscillator to the size of the window.

[0002]

2. Description of the Related Art For example, in a laser drilling machine that drills a printed circuit board with a laser, a beam diameter of a laser beam emitted from a laser oscillator by an aperture is set to a predetermined size in order to improve processing accuracy and workability. Prepare. The aperture of such a laser beam machine is shown in FIGS.
This will be described below. FIG. 6 is an overall configuration diagram of an optical system of a conventional laser drilling machine, and FIG. 7 is a sectional view of a portion A in FIG.
In the figure, reference numeral 1 denotes a laser oscillator which outputs a laser beam 2. 3a to 3c are mirrors. Reference numeral 4 denotes an aperture which is made of a material such as copper which does not transmit the laser beam 2 and has a high thermal conductivity. The aperture 4 has a window 4a at a predetermined position (in this case, a circular through hole having a diameter of about 1 to 8 mm), and a side face 4 on the incident side of the laser beam 2.
b is formed in a conical surface. The aperture 4 is arranged such that the axis of the window 4 a coincides with the axis of the beam diameter of the laser beam 2. 5 is an optical unit composed of a lens or the like, 6
Is a printed circuit board.

Next, the operation of a conventional laser beam machine will be described. The laser beam 2 emitted from the laser oscillator 1 is
It is bent at right angles by the mirrors 3a and 3b, and the aperture 4
Incident on. Then, the passing beam 2a passing through the window 4a
Is bent by the mirror 3c at a right angle, and then condensed by the optical unit 5 to form a hole in the printed circuit board 6. Further, the reflected beam 2b reflected by the side surface 4b is reflected to a place other than the laser oscillator 1, and prevents the laser oscillator from being damaged by the reflected beam 2b. Since the entire laser processing machine is shielded from the surroundings by a cover (not shown), the reflected beam 2b does not leak outside the laser processing machine.

When the beam diameter of the laser beam 2 is adjusted in advance, the height of the optical unit 5 from the surface of the printed circuit board 6 can be fixed even when a different hole diameter is processed. As a result, not only the hole machining accuracy is improved, but also the workability is improved.

[0005]

However, the aperture 4
Is made of copper, most of the reflected beam 2b
Reflected by b, its power does not decay. The reflected beam 2b has high directivity. For this reason, depending on the laser output, the portion of the laser beam machine where the reflected beam 2b enters may be gradually heated and locally reach 150 ° C. in some cases. For example, if the heated location is the holding portion of the mirror 3b, the position of the mirror 3b is shifted due to the thermal deformation of the holding portion, the optical axis of the laser beam 2 is tilted, and the processing energy supplied to the processing portion is reduced. And the desired processing cannot be performed.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a laser beam machine capable of appropriately processing a laser beam reflected by an aperture.

[0007]

To achieve the above object, according to the first aspect of the present invention, an aperture having a window is provided.
In a laser processing machine that limits a laser beam emitted from a laser oscillator to the size of the window, a hollow cover that is formed of a material having a high laser beam absorptivity and whose inner surface is parallel is provided. The inner surface is arranged on the laser beam incident side of the aperture so as to be parallel to the laser beam, and the laser beam reflected by the aperture is irradiated on the inner surface.

[0008] The invention of claim 2 is characterized in that, in claim 1, cooling means for the cover is provided to cool the cover.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. 1 is an overall configuration diagram of an optical system of a laser processing machine according to the present invention, FIG. 2 is a view as viewed from B in FIG. 1, FIG. 3 is a cross-sectional view taken along line CC of FIG. 6 and 7 having the same functions or the same functions as those in FIGS. In the figure, reference numerals 10 and 11 are apertures. As shown in FIG. 4, the aperture 10 has a side surface 10 b on the incident side of the laser beam 2 formed in a conical surface having an angle θ (θ = 75 degrees in the illustrated case) from the outer edge of the window 10 a, and a male screw 12 on the outer periphery. Are formed. The apertures 10 and 11 are provided with windows 10a, 11a and side faces 10b, 11
Although the length of b in the axial direction is different, other dimensions (outer diameter, length of male screw 12, angle θ, etc.) are the same. Reference numeral 13 denotes a cylindrical cover, which is formed of a material having a low reflectance, for example, carbon, and has a female screw 14 screwed to the male screw 12 at one inner end. The cover 13 is inserted from one side of the holder 15 so as to be in close contact with the holder 15,
It is fixed to the holder 15 by means not shown. A cooling water passage 16 penetrates the holder 15 and is connected to a cooling water circulation device (not shown) via a connection terminal 17. Reference numeral 18 denotes a support, which is integral with the holder 15, and a piston 21 of an air cylinder 20 is
It is fixed to.

Next, the dimensions of each part will be described. The covering length L of the cover 13, that is, from the end M of the cover 13 when the aperture 10 is screwed to the cover 13,
a, the inner diameter D of the cover 13, the diameter K of the laser beam 2, the minimum diameter d of the window 10a, and the angle θ.
Have the relationship of the following formulas 1-3. (1) D> K Equation 1 (2) L> (D−d) / 2 · tan2θ Equation 2 (3) 90> θ ≧ 45 Equation 3 Next, the operation of the present embodiment will be described. The air cylinder 20 is operated in advance, and the center of one of the window 10a and the window 11a (the window 10a in this case) is aligned with the center of the laser beam 2 and positioned. The laser beam 2 emitted from the laser oscillator 1 is bent at a right angle by the mirrors 3a and 3b, and enters the aperture 10. And window 10
The beam 2a that has passed through a is bent at a right angle by the mirror 3c and then condensed by the optical unit 5 to form a hole in the printed board 6.

On the other hand, the reflected beam 2b is, as shown in FIG.
The reflected beam 2bn reflected at the end N of the cover 0a
3 and is absorbed by the cover 13 and converted into heat. Since the cover 13 is tightly fixed to the water-cooled holder 15, the temperature hardly rises. Further, since the aperture 10 is also cooled via the female screw 14, the temperature rise value is small, and the diameter of the window 10a does not increase due to heat.

Although the entire cover 13 is made of carbon in the above description, for example, the holder 15 may be made of copper, and cylindrical carbon may be press-fitted or bonded to a portion irradiated with the reflected beam 2b. Further, the cover 13 and the holder 15 may be made of integral copper and the inner surface may be blackened, or the inner surface may be made of iron and the inner surface may be treated with triiron tetroxide coating.

In the above embodiment, the number of apertures is two. However, a large number of apertures having different window diameters are prepared and held by the switching means so that the center of the window coincides with the axis of the laser beam. With this configuration, the types of hole diameters that can be processed can be further increased.

Although the angle θ is set to 90> θ ≧ 45,
When the coating length L can be increased, the life of the aperture 10 can be extended by increasing θ as much as possible and increasing the thickness of the window 10a in the axial direction.

FIG. 5 shows another embodiment of the present invention, and corresponds to FIG. 4 described above. In the figure, reference numeral 30 denotes an air nozzle, which is fixed to the cover 13, and the end 30a is connected to a compressed air source (not shown). In this embodiment, since the cover 13 and the aperture 10 are cooled by air, the device configuration is simplified.

[0016]

As described above, according to the present invention,
In a laser beam machine that limits a laser beam emitted from a laser oscillator to the size of the window by an aperture having a window, the laser beam is formed of a material having a high absorptivity of the laser beam, and the inner surface of the hollow is parallel. A cover was provided, and the cover was arranged on the laser beam incident side of the aperture so that the inner surface became parallel to the laser beam, and the inner surface was configured to irradiate the laser beam reflected by the aperture to the inner surface. Therefore, the reflected beam can be reliably absorbed. As a result, it is possible to prevent the deviation of the optical axis of the laser beam, the deformation of the components in the laser beam machine, and the like.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an optical system of a laser processing machine according to the present invention.

FIG. 2 is a view as viewed from B in FIG. 1;

FIG. 3 is a sectional view taken along line CC of FIG. 2;

FIG. 4 is an enlarged view of a part D in FIG. 3;

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is an overall configuration diagram of an optical system of a conventional laser drilling machine.

FIG. 7 is an enlarged view of a portion A in FIG. 6;

[Explanation of symbols]

 2 laser beam 2b reflected beam 10 aperture 10b side 13 cover

Claims (2)

[Claims] 1. A laser processing machine in which an aperture provided with a window limits a laser beam emitted from a laser oscillator to the size of the window, wherein the laser beam is formed of a material having a high absorptivity of the laser beam. A parallel hollow cover is provided, and the cover is arranged on the laser beam incident side of the aperture so that the inner surface is parallel to the laser beam, and the inner surface is irradiated with the laser beam reflected by the aperture. A laser processing machine characterized in that the laser processing machine is configured to perform the following. 2. The apparatus according to claim 1, further comprising cooling means for cooling said cover.
2. The laser beam machine according to claim 1.