JPH02137688A - Laser beam machine - Google Patents

Abstract

PURPOSE:To obtain a defectless laser welded part by finely displacing an expander lens repeatedly in the direction perpendicular to the optical axis. CONSTITUTION:The laser beam machine is provided with an expander lens 2 condensing lens 4 on the optical axis of a laser beam 7 emitted from a laser oscillator 1. A work 5 is irradiated with the condensed light spot of the laser beam and subjected to working. A drive device (means) 9 is provided so as to finely displace the expander lens 2 repeatedly in the direction perpendicular to the optical axis. Therefore, a defectless welded part can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing device, and particularly to a laser processing device suitable for butt welding.

[Conventional technology]

First, the configuration of a conventional laser processing apparatus and the butt welding method of a workpiece using the laser processing apparatus will be explained with reference to FIG. In the figure, l is a laser oscillator, 2 is an expander lens that is a combination of a concave lens 2a and a convex lens 2b, 3 is a reflection mirror, and 4 is a condensing lens.These parts are arranged on the optical path to configure the optical system of the laser processing device. are doing. On the other hand, the workpiece 5, which is made up of two base materials that make up the butt joint, is placed on an X-Y table (not shown)! ! 6 indicates a welding line along the abutting surfaces of the workpieces 5.

The laser beam 7 emitted from the laser oscillator 1 above is
The beam diameter is expanded by passing through the expander lens 2, and is further transmitted through the reflecting mirror 3. Workpiece 5 passes through condensing lens 4
is irradiated. In this case, the distance between the condenser lens 4 and the workpiece 5 is such that the focused spot of the laser beam irradiates the workpiece 5 at a position slightly shifted from the focal point of the condenser lens 4. distance is adjusted. Here, the workpiece 5 is butt-welded by moving the workpiece 5 by controlling the X-Y table by NC so as to scan the focused spot of the laser beam along the welding line 6. Ru. 8
indicates the bead, and arrow P indicates the welding direction.

The above example shows a butt welding process, but the same laser processing equipment was used to cut and scribe.

It is well known that various types of processing such as drilling can be performed.

(Problems to be Solved by the Invention) However, when butt welding workpieces using the conventional laser processing apparatus described above, the following problems remain.

That is, as mentioned above, during butt welding, the X-Y table on which the workpiece 5 is mounted is moved so that the focused spot of the laser beam is scanned along the welding line 6 on the workpiece side. Control. Therefore, in order to obtain a welded part without welding defects, high tracing accuracy is required for the X-Y table to prevent misalignment from the weld line 6, and a groove along the weld line 6 of the workpiece 5 is required. The distance between the roots is almost zero, and the root surfaces are in close contact with each other without any gaps, that is, the workpiece 5
It is required that the bevel beveled with high precision so that the root surface has a high degree of smoothness. In this regard, if the groove machining accuracy of the workpiece 5 is low and a large root gap remains between the butt-face tiles of the workpiece, melt will drop during welding and welding defects such as blowholes will occur. Moreover, if the tracing accuracy of the X-Y table is low, the weld line 6 may be misaligned, resulting in unwelded parts.

The present invention has been made in consideration of the above points, and even if the groove machining accuracy of the workpiece to be butt welded is somewhat low, it can compensate for this and achieve good butt welding. An object of the present invention is to provide a laser processing device that can perform the following steps.

[Means to solve the problem]

In order to solve the above problems, the laser processing apparatus of the present invention includes a drive means for repeatedly slightly displacing the expander lens in a direction perpendicular to the optical axis for the expander lens, which is an optical system component of the laser processing apparatus. It shall be composed of:

[Effect]

In the above configuration, the driving means is a driving device that vibrates so as to repeatedly displace the expander lens assembly in a direction perpendicular to the optical axis with one cycle of a predetermined amplitude. Here, when the expander lens is slightly displaced in the direction perpendicular to the optical axis of the laser beam during the process of butt welding the workpiece, the focused spot of the laser beam irradiated onto the workpiece The irradiation position is also slightly displaced with respect to the optical axis.

Therefore, the workpiece is moved along the welding line while applying vibration to the expander lens using the drive device so that the condensed spot is slightly displaced in the width direction of the route interval. As a result, the focused spot scans on a trajectory that zigzags along the welding line of the workpiece. This produces the same effect as the weaving welding method, and even if some root gap remains between the butt surfaces of the workpiece, the weld bead is formed to fill this gap, so the welding There is no welding defects such as blowholes, and X-Y
Even if the scanning accuracy of the table is somewhat low, the error can be covered by the zigzag scanning of the focused spot, eliminating the risk of misalignment from the weld line.

〔Example〕

FIG. 1 is a block diagram of an embodiment of the present invention showing a state where butt welding is being performed, and the same parts corresponding to those in FIG. 4 are given the same reference numerals. That is, according to the invention, a drive device designated by reference numeral 9 is coupled to the expander lens assembly 2. As shown in FIG. This drive device 9 is a kind of vibrator,
Vibration is applied to the expander lens 20 assembly so as to repeatedly slightly displace it in a direction perpendicular to the optical axis of the laser beam 7 (arrow Q). Note that the vibration frequency, amplitude, etc. are configured to be appropriately adjusted from the outside.

Next, the effect of the above configuration will be explained with reference to FIG. 2. In the figure, when the optical axis of the laser beam 7 emitted from the laser oscillator is 0, the focal length of the condenser lens 4 is f, and the center of the expander lens 2 is aligned with the optical axis 0, the laser beam 7 is 4 and is focused at the focal point A of the condenser lens 4 as shown by the solid line in the figure. Also, at this point, the irradiation surface of the workpiece is moved to a position slightly away from the focal point A, zs1.
When set to S2, the condensing spot on the irradiation surface is Sll,
The light is irradiated to a position centered on optical axis 0, as indicated by 321 (solid line). On the other hand, if the center of the expander lens 2 is slightly displaced in the vertical direction by Δl with respect to the optical axis O, as shown by the dotted line, the locus of the laser beam on the optical path changes as shown by the dotted line. Therefore, the focused spot irradiated on the irradiation surface position SL, S2 described above is S12.3.
22 (dotted line), it becomes deviated from the optical axis O. That is, when the expander lens 2 is displaced in the direction perpendicular to the optical axis O, the condensed spot irradiated on the irradiation surface s1°S2 near the focal point of the condensing lens 4 changes from 311 to 312. 321 to 322.

Therefore, in FIG. 1, the expander lens 2 is assembled by driving the drive device 9 so that the focused spot of the laser beam applied to the workpiece 5 is slightly displaced from the welding line 6 in the left and right width directions. The optical axis of the laser beam is 0
When vibration is applied in the vertical direction (vertical direction in the illustrated example) and at the same time the workpiece 5 is moved along the welding line 6 via the X-Y table, the vibration frequency applied by the drive device W9.

The focused spot vibrates slightly on the irradiated surface of the workpiece 5 in a direction perpendicular to the welding direction in accordance with the amplitude. In addition, Fig. 3 (a
) and (b) schematically represent examples of scanning loci of the condensed spot along the welding line 6, and T indicates the scanning locus of the condensed spot.

In this way, the focused spot of the laser beam is swung left and right along the welding line 6 on the workpiece 5,
By selecting appropriate values for the amplitude and vibration frequency, the welding progresses in the same way as the weaving welding method, and even if some distance remains between the butt surfaces of the base metal of the workpiece 5, Since a weld bead is formed so as to fill this gap, the melt falls off and welding without welding defects such as blowholes is obtained. Further, even if the tracing accuracy of the X-Y table is somewhat low, there is no risk of straying from the welding line 6 because the laser beam is scanned in a zigzag manner with a width that forms the focal spot of the laser beam.

Note that although the above description has been made regarding the case of butt welding, similar effects can be obtained when fillet welding is performed. It goes without saying that by operating the laser processing device with the drive device 9 stopped, cutting, scribing, etc. of the workpiece can be performed without any problem.

[Effects of the Invention] Since the laser processing apparatus of the present invention is configured as described above, it achieves the following effects.

That is, by providing a driving means that repeatedly slightly displaces the expander lens in a direction perpendicular to the optical axis, and slightly displacing the focused spot of the laser beam to the left and right with respect to the welding line during butt welding, (1) To give a similar effect to the weaving welding method to butt welding of workpieces, and to form a weld bead to fill the gap even if some gap remains between the butt surfaces of the workpieces. This results in defect-free welds.

(2) Even if the tracing accuracy of the X-Y table that moves the workpiece is somewhat low, stable welding can be performed along the welding line without fear of misalignment.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a laser processing apparatus according to an embodiment of the present invention showing a butt welding process state, Fig. 2 is an explanatory diagram of the operation of Fig. 1, and Figs. 3 (a) and (b) are for micro displacement. FIG. 4 is a schematic diagram of the scanning locus of the condensed laser beam spot, and FIG. 4 is a configuration diagram of a conventional laser processing apparatus showing a butt welding state. In the figure, 1: laser oscillator, 2: expander lens, 4: condensing lens, 5: workpiece, 6: welding line, 7: laser beam, 9: drive device, 0: optical axis of laser beam, Sl, 32: Focused spot irradiation surface, Sll,
Sl2. 321. 322: Focusing spot, T: Focusing spot = 10- Figure 1 (G) (b) Figure 3

Claims (1)

[Claims] 1) In a laser processing device in which an expander lens and a condensing lens are arranged on the optical axis of a laser beam emitted from a laser oscillator, and processing is performed by irradiating a focused spot of the laser beam toward a workpiece, the expander A laser processing device characterized by comprising a driving means for repeatedly slightly displacing a lens in a direction perpendicular to an optical axis.