JP3357170B2 - Laser processing machine - Google Patents

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 having a table movable in the X-axis direction and a processing head movable on a portal column in the Y-axis direction.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory view showing an outline of a conventional laser beam machine. A laser processing machine generally designated by reference numeral 1 is a table 3 mounted on a bed 2 so as to be movable in the X-axis direction.
Having. A guide surface 6 in the Y-axis direction is provided on the front surface of a column 5 erected in a gate shape on the bed 2, and a processing head 10 is slidably supported along the guide surface 6. A feed screw 8 driven by a servomotor controls the processing head 10 along the Y-axis direction. The column 5 is equipped with a laser oscillator, and the laser beam output from the laser oscillator is sent to the mirror 22 via the light guide tube 20. The laser beam reflected by the mirror 22 enters one end of a light guide tube 24 parallel to the feed screw 8. The other end of the light guide tube 24 is connected to a mirror 26 provided at the upper end of the processing head 10.
Is joined to. Therefore, as the processing head 10 moves on the Y axis, the length of the light guide tube 24 changes by the stroke of the Y axis movement. The laser beam that has entered the processing head 10 is condensed by a condenser lens in the processing head 10. The focused laser beam is applied to the nozzle 12
Irradiates the work on the table 3.

However, in general, a laser beam is not a parallel beam but a diffused beam having a divergence angle of about 2 to 3 milliradians. Therefore, when the length of the laser beam conduction path from the laser oscillator to the condenser lens disposed in the processing head (hereinafter referred to as the optical path length) changes, the diameter of the incident laser beam at the condenser lens changes, and the focal position is changed. The focused diameter of the laser beam at the point changes. This is a major factor that makes it difficult to perform stable processing over the entire processing stroke in the conventional laser processing machine.

Hereinafter, the effect of a change in optical path length on laser processing conditions will be described in detail. FIG. 5 is a model diagram of a laser processing machine showing the spread of a laser beam output from a laser oscillator. Now, the laser beam diameters at point A and point B are DA and DB, the distance between point A and point B is L (corresponding to the processing stroke), and the divergence angle of the laser beam is φ. For example, DB = 20 mm , L = 1500m
Assuming that m and φ = 3 milliradians, DA = DB + L × φ ‥‥‥‥ (1) = 20 + 1500 × 0.003 = 24.5 mm. FIG. 6 shows the incident laser beam diameter D at the focusing lens.
And the laser beam focusing diameter δ at the focal position. When a laser beam in a fundamental mode generally called a GAUSSIAN BEAM mode passes through a condenser lens,
The light collection diameter δ at the focal position is represented by the following equation. δ = 1.27λ × (f / D) + K × (D3 / f2) ‥‥‥‥ (2) The first term is physically known as the diffraction limit, and the second term is known as the spherical aberration. Here, λ: wavelength of light f: focal length of lens D: diameter of incoming laser beam K: constant determined by lens material and lens shape Now, for convenience, let the laser beam of CO2 laser be a parallel beam, and f = The light-collecting diameters δA and δB at the focal point after passing through the lens at points A and B in FIG. 5 were calculated using 63.5 mm, the lens material as ZnSe (zinc selenium), and the lens shape as plano convex. Looking at, DA = 24.
5 mm, DB = 20 mm, λ = 10 μm, K = 0.03
From 0, δA = 0.14 mm and δB = 0.10 mm. Average energy density ratio EB at each focal position
Since / A is inversely proportional to the light-collecting area, point B is approximately twice as large as point A.

The instability of processing in laser processing is caused by various factors. It is generally accepted that a change in the focused diameter of a laser beam, that is, a change in energy density is a particularly large factor. As the size of the laser beam machine increases, the variation L of the optical path length further increases, and the influence of the variation of the condensing diameter of the laser beam increases.

As described above, in a laser processing machine of the type in which the processing head is moved along one axis along the Y axis, the distance from the laser beam exit of the laser oscillator to the processing point generally changes, and the laser beam is condensed. There was a problem that the diameter changed and processing became unstable. On the other hand, according to Japanese Patent Application No. Hei 4-151631, the applicant of the present application has set the amount of change in the distance from the laser beam exit of the laser oscillator to the processing point even in the one-axis moving method of the processing head of the portal laser processing machine. We propose a laser processing machine that minimizes this change in distance and does not hinder the processing stability in practice.

Although the performance of the conventional portal-type laser beam machine has been dramatically improved by this, the effect of vibration cannot be ignored if the speed is to be further increased. Therefore, the effect of vibration in processing with rapid acceleration / deceleration in a laser processing machine to which the method of Japanese Patent Application No. 4-151163 is applied will be described with reference to FIG. The inertial force generated when the machining head is moved at a rapid acceleration / deceleration acts on the turning light guide tube 550, and the turning light guide tube vibrates. in this case,
Since the telescopic member 600 'is provided in the middle of the turning light guide tube, the vibration amplitude increases due to a decrease in rigidity of the turning light guide tube, an increase in weight, and play of the expandable member. This vibration disturbs the parallelism of the mirrors mounted on the turning devices provided at both ends of the turning light guide tube. As a result, the optical axis of the laser beam entering the condenser lens fluctuates, and the focal position oscillates in a direction perpendicular to the optical axis. For this reason, when high-speed processing is performed by the laser processing machine of the present method, as shown in FIG. 8, vibration is generated in a direction perpendicular to the traveling direction of the cutting processing during acceleration / deceleration, and as a vibration mark on the cut surface of the work. When the commercial value of the machined work is lost and self-excited vibration is generated, the amplitude becomes large and the cutting itself becomes impossible.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in a laser beam machine and eliminates the influence of inertia generated in high-speed machining with rapid acceleration / deceleration, and has a substantially constant optical path length. The purpose of the present invention is to provide a laser beam machine.

[0009]

An object of the present invention is to provide a table 120 movable in the X-axis direction, a processing head 300 movable in the Y-axis direction on the portal column, and a laser beam outlet in the X-axis direction. In a laser beam machine 100 including a laser oscillator 200 and a light guide device 500 for coupling the laser oscillator and a processing head, the laser beam machine is coupled to a laser beam outlet of the laser oscillator by a telescopic member, and is movably disposed in the X-axis direction. A telescoping device 600 that guides the laser beam upward through an optical path having a mirror, and a first turning device 530 that is rotatably disposed above the telescopic device and guides the laser beam in the horizontal direction through an optical path that has a mirror. A second pivoting device 570, which is pivotably disposed above the processing head and guides the laser beam downward by an optical path having a mirror, and first and second pivoting devices. Combining the long swivel light pipe 550 of
Thus, the problem is solved by the laser beam machine that constitutes the light guide device.

[0010]

The working head 300 is linearly moved in the Y-axis direction while being restrained by the guide surface of the column 150. Accordingly, the turning devices 530 and 570 at both ends of the turning light guide tube 550 perform a rotating motion, and the first turning device 530 is a telescopic device 60.
Since a linear motion in the X-axis direction is performed together with 0, the turning light guide tube performs a smooth turning motion. At this time, the laser oscillator 200
The optical path length between the optical head and the processing head fluctuates by the length of the expansion and contraction of the expandable member. In addition, since the swiveling light guide tube has an integral structure, there is no backlash, and it can be lightweight and have high rigidity. Therefore, even in high-speed machining with sudden acceleration / deceleration, the influence of vibration can be eliminated, and Mirror is kept parallel. In addition, the expansion and contraction member that couples the laser beam outlet of the laser oscillator and the light guide device,
Since only one tenth or less of the working distance of the working head is expanded or contracted, the optical axis of the laser beam being processed is not changed.

[0011]

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a front view. A laser processing machine, generally designated by the reference numeral 100, includes a table 12 that moves on a bed 110 in the X-axis direction.
0, the table 120 places the work 130 on the upper surface. In addition, a column 150 is erected on the bed 110. The column 150 slidably supports the saddle 310 of the processing head 300 via two guide surfaces 333. The saddle 310 is driven in a Y-axis direction orthogonal to the X-axis by a lead screw 330 driven by a servomotor (not shown). At the lower end of the processing head 300, a nozzle 350 that irradiates the focused laser beam onto the table 120 is mounted. Column 15
A frame 160 is erected on the bed 110 at the rear of the “0”, and the laser oscillator 200 is fixed on the frame 160. On the bed 110 on both sides of the laser oscillator 200, a power supply device 220 for the laser oscillator and a high-power board 210 including a control device for the entire laser processing machine are provided.
The laser beam emitted from the laser oscillator 200 is applied to the processing head 30 via a light guide device generally denoted by reference numeral 500.
0.

FIG. 3 is a longitudinal sectional view of the light guide device 500.
The laser beam oscillated by the laser oscillator 200 is introduced from the light entrance 510 to the light guide device 500. Light incident part 51
Numeral 0 is formed inside the housing 531, and is connected to a laser beam outlet of the box-shaped laser oscillator 200 via an elastic member 615. The housing 531 includes the oscillator 20
The laser beam is bent at a right angle and guided upward by an optical path including a mirror device 515 disposed at an angle of 45 ° with respect to the laser optical axis of zero. At the bottom of the housing 531
Guide member 60 disposed on frame 160 in the X-axis direction
A slide block 610 that slides on the top 5 is provided, and constitutes a telescopic device 600. The telescopic device 600 holds a first turning device 530 at the upper part. The first turning device 530 includes a bearing 534 on the top of the housing 531.
Hollow shaft 532 rotatably mounted via
And a block 552 connected to the upper end of the hollow shaft 532. The block 552 includes the mirror device 54
The laser beam is bent at a right angle and guided in the horizontal direction by an optical path with zero. The block 552 supports one end 554 of a long swirling light guide tube 550 disposed in the horizontal direction so as to be swivelable.

The other end 555 of the turning light guide tube 550 is rotatably supported by a second turning device 570 provided on the processing head 300 side. Second turning device 570
Is the bearing 5 on the housing 320 at the top of the machining head.
Hollow shaft 5 rotatably mounted via 75
35, and a block 553 connected to the upper end of the hollow shaft 535. The block 553 supports the other end 555 of the swirling light guide tube 550 so as to be swivelable, and guides the laser beam downward by bending the laser beam at a right angle through an optical path including the mirror device 560. With such a configuration, the second turning device 570 can reciprocate in the Y-axis direction together with the processing head 300.

The light guide tube 550 makes a revolving motion about the axis of the first revolving device 530 as a revolving center. That is, both ends of the light guide tube 550 are supported by the first turning device 530 and the second turning device 570, and the turning radius is constant. Since it is supported movably along the axial direction,
Even when the second turning device 570 is constrained to make a linear motion along the Y axis, the light guide tube 550 can make a turning motion. The block 553 includes the third mirror device 56.
0 is provided, and the optical axis of the laser beam sent from the light guide tube 550 is bent at a right angle and guided downward. The bent laser beam is supplied to the nozzle 350 through a condenser lens (not shown) of the processing head 300 provided below the saddle 310. The laser beam emitted from the nozzle 350 performs necessary processing on the work 130.

The light guide device of the present invention is constructed as described above.
The optical path length up to is almost constant. That is, in FIG. 1, when the processing head 300 moves the maximum distance along the Y axis, the first turning device 530 and the second turning device 57
The angle between the center line of the table 120 and the line connecting the two centers of 0 is θ, and the distance between the first and second turning devices is R.
Then, the difference r between the optical path lengths is: r = R−Rcos θ = R (1−cos θ). Actually, the value of θ is small, and the change amount of the optical path length is small. For example, when R = 3000 mm and θ = 14.5 °, r = 95 mm. Therefore, as compared with the case where the optical path length changes by the moving stroke of the processing head in the Y-axis direction as in the prior art, the change in the entire optical path length is extremely small, and the processing conditions hardly change.

Further, since the swiveling light guide tube 550 has an integral structure, there is no backlash, light weight and high rigidity can be provided. Therefore, even in high-speed machining involving rapid acceleration / deceleration, the influence of vibration can be eliminated. Yes, mirror 54 in the optical path
The parallelism of 0,560 is maintained. In addition, laser oscillator 2
Since the expansion and contraction member 615 that couples the laser beam outlet of the laser beam 00 and the light guide device 500 only expands and contracts by a length equal to or less than one tenth of the working distance of the processing head 300, the optical axis of the laser beam being processed is Will not change.

In this embodiment, an example is shown in which the first turning device 530 is disposed on the center line of the table 120 and at a position half the moving stroke of the processing head 300 in the Y-axis direction. However, the present invention is not limited to this, and it can be provided at any fixed portion on the laser beam machine. Further, in the present invention, the first turning device is provided so as to be movable along the X-axis direction, but instead of this, a telescopic device is provided between the second turning device 570 and the processing head 300. This makes it possible to make the second turning device movable in the X-axis direction simultaneously with the Y-axis direction.

[0018]

As described above, according to the present invention, in the laser beam guide device of the laser beam machine, the end on the processing head side performs a linear motion in the Y-axis direction, while the end on the opposite side is in the X-axis direction. The optical path between the laser oscillator and the processing head is constituted by a rotating light guide tube of a fixed length that performs a linear motion in the direction and performs a rotating motion as a whole, and uses only a telescopic member only at the joint with the laser oscillator. With this configuration, the entire optical path length becomes substantially constant, and stable laser processing conditions are achieved. Also, since the swiveling light guide tube has an integral structure, there is no backlash, it can be lightweight and has high rigidity, and therefore, it is possible to eliminate the influence of vibration caused by inertial force during high-speed machining with rapid acceleration / deceleration. As a result, the parallelism of the mirror in the optical path is maintained. Furthermore, even after long hours of operation, there is no increase in play due to wear of the elastic member,
High performance can be maintained. Therefore, by minimizing the amount of change in the optical path length and eliminating the influence of vibration and maintaining the parallelism between the plurality of mirrors, a uniform machining state is achieved in all the strokes of the machining head in the Y-axis direction. The precision of the machined surface is improved. Since the processing state is constant, not only does it not require operations such as correcting the processing conditions on the processing program, but also achieves high-speed processing that makes maximum use of the output of the oscillator, and laser processing with extremely high productivity Machine can be provided. Moreover, since the present invention does not require a complicated configuration, a laser processing machine having the above-described excellent performance can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a laser beam machine according to the present invention.

FIG. 2 is a partial cross-sectional and front view of the embodiment of FIG.

FIG. 3 is a longitudinal sectional view of the light guide device in the embodiment of FIG.

FIG. 4 is a perspective view of a conventional laser beam machine.

FIG. 5 is an explanatory diagram showing the spread of a laser beam output from a laser oscillator.

FIG. 6 is an explanatory diagram showing the relationship between the diameter of the incident laser beam at the focal lens and the focused diameter of the laser beam at the focal position.

FIG. 7 is an explanatory diagram showing the influence of vibration in machining accompanied by sudden acceleration / deceleration.

FIG. 8 is an explanatory diagram showing vibration traces generated on a cut surface by laser processing with rapid acceleration and deceleration.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 laser processing machine 120 table 150 column 200 laser oscillator 300 processing head 500 light guide device 515, 540, 560 mirror 530 first turning device 550 turning light guide tube 570 second turning device 600 telescopic device 615 expandable member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-337674 (JP, A) JP-A-5-65488 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 26/00-26/42

Claims (1)

(57) [Claims] 1. A bed, a table mounted on the bed so as to be movable in the X-axis direction, a column erected on the bed and having a guide surface in the Y-axis direction, and a column on the guide surface. A processing head movably mounted, a laser oscillator fixed on the side opposite to the processing head of the column and having a laser beam exit in the X-axis direction, and a light guide device coupling the laser oscillator and the processing head. A laser processing machine equipped with a frame arranged on a bed in the X-axis direction.
Guide member and a slide that slides on the guide member.
Housing with the
A telescopic device that has a telescopic member for connecting the laser beam outlet and guides the laser beam upward through an optical path having a mirror; and Lead to the first
A turning device, a second turning device, which is rotatably provided above the processing head and guides a laser beam downward by an optical path having a mirror, and an elongate connecting the first and second turning devices. Laser processing machine provided with a turning light guide tube.