JP2004114090A - Laser machining method, and laser machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily increase the energy density of laser light from a laser diode and to suppress its directional dependency. <P>SOLUTION: A prism 21 deflecting a part of laser light from a laser diode applied from the nozzle 16 of a head 14 is provided. The laser light deflected by the prism 21 as a deflection irradiation part is superimposed on a direct irradiation part directly applied to the object W to be worked. Thus, the energy density of the laser light from the laser diode relatively low in output is increased to improve its working performance, and further, the irradiation shape is made close to a square shape, so that its directional dependency on the working is suppressed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing method and a laser processing apparatus that perform processing by irradiating a workpiece with a laser.
[0002]
[Prior art]
Conventionally, laser processing has been performed in which a workpiece is irradiated with laser to perform welding processing, cutting processing, and surface processing.
As a laser processing apparatus for performing laser processing, laser light oscillated by a laser oscillator is guided to a head installed above a table for fixing a workpiece, and is narrowed down by an optical system toward a workpiece from a torch. There is known a technique for performing processing on a workpiece by irradiating and relatively moving the workpiece and the head (for example, see Patent Document 1).
Some laser beams are split into two by a prism and laser processing is performed with two laser spot beams (see, for example, Patent Document 2).
[0003]
[Patent Document 1]
JP-A-8-215874 (page 4-5, FIG. 1)
[Patent Document 2]
JP 2001-47272 A (page 7, FIG. 14)
[0004]
By the way, as a laser beam used for this laser processing, a CO ₂ laser and a YAG laser are generally used. However, in recent years, a laser diode (LD) capable of high-efficiency oscillation instead of these CO ₂ laser and YAG laser is used. ) (Direct Diode Laser) processing using a laser beam is being put to practical use.
Compared with CO ₂ laser and YAG laser, this DDL processing can make the laser oscillator more compact, and the oscillation wavelength is about 10600 nm for CO ₂ laser and about 1064 nm for YAG laser. Since it is in the range of 800 to 900 nm, the absorption rate to various materials is high and the workability is good. In addition, the oscillation efficiency of laser light is about 6% for a CO ₂ laser and about 2% for a YAG laser. It has an excellent merit that it is very good at 30%.
[0005]
Here, as shown in FIG. 12, a laser processing apparatus that performs DDL processing guides laser light from a laser oscillator using a laser diode as an oscillation source to a head 1 and narrows it down by an optical system 2 provided in the head 1. As shown in FIG. 13, the groove of the workpiece W is irradiated from the nozzle 3 to perform processing such as welding.
[0006]
[Problems to be solved by the invention]
By the way, the laser oscillator of this laser processing apparatus uses a laser diode array in which a laser diode bar in which a plurality of laser diodes are arrayed is stacked as an oscillation source. The laser light oscillated from the laser diode array has an irradiation shape S of a rectangular shape. For this reason, although it is difficult to improve the light condensing performance and the output itself is improved, there is a problem that the energy density is low as compared with the CO ₂ laser and the YAG laser. Furthermore, when the irradiation shape S is a rectangular shape, there is a problem that the amount of heat input per unit length varies depending on the processing direction, and there is a direction dependency.
[0007]
The present invention has been made in view of the above circumstances, and laser processing using a laser diode that can extremely easily increase the energy density and can perform good processing with reduced direction dependency. It is an object to provide a method and a laser processing apparatus.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the laser processing method of the present invention provides a direct irradiation unit that directly irradiates a workpiece with laser light when the workpiece is irradiated with laser light from a laser diode. A deflection irradiation unit for deflecting and irradiating a part of the laser beam is superimposed.
[0009]
As described above, according to the present invention, a part of the laser beam is deflected and superimposed on the direct irradiation unit that directly irradiates the workpiece as the deflection irradiation unit. The energy density of laser light from a laser diode having a relatively low density can be increased. Moreover, the irradiation shape can be approximated to a square shape by superimposing.
[0010]
Further, in the present invention, the direct irradiation part of the laser beam is moved along the groove of the workpiece so as to perform welding on the workpiece, and the deflection irradiation part superimposed on the direct irradiation part is moved in the processing direction. The laser beam may be reciprocated in an orthogonal direction, or the laser beam direct irradiation unit may be moved, and the deflection irradiation unit superimposed on the direct irradiation unit may be reciprocated in a direction along the processing direction.
And if it does in this way, it can weld reliably also with respect to a wide groove | channel, Furthermore, the structure | tissue control of a welding part and the removal of a bubble can be performed.
[0011]
The laser processing apparatus of the present invention includes a laser oscillator using a laser diode as an oscillation source, a head for irradiating a workpiece with laser light from the laser diode of the laser oscillator, and a laser beam irradiated from the head to be processed. And an optical member that deflects the laser light emitted from the head so as to be superimposed on the direct irradiation part that is directly irradiated onto the object.
[0012]
Also in the case of this laser processing apparatus, a part of the laser beam can be deflected and superposed on the direct irradiation unit that directly irradiates the workpiece as the deflection irradiation unit, so that the oscillation efficiency of the laser beam is extremely good. However, the energy density of laser light from a laser diode having a relatively low energy density can be greatly increased. Moreover, the irradiation shape can be approximated to a square shape by superimposing.
[0013]
In addition, a moving mechanism for moving the workpiece and the head relative to each other is provided, and the optical member is swung in one or both of a direction orthogonal to the moving direction of the head relative to the workpiece by the moving mechanism and a direction along the moving direction. A drive mechanism may be provided, and in this way, when moving the direct irradiation part of the laser beam along the groove of the work piece to perform welding on the work piece, it is superimposed on the direct irradiation part. The deflection irradiation unit is reciprocated in the direction orthogonal to the machining direction to reliably weld a wide groove, or the deflection irradiation unit directly superimposed on the irradiation unit is reciprocated in the direction along the machining direction to Tissue control and bubble removal can be performed.
[0014]
Further, the optical member may be movable along the optical axis direction of the laser light emitted from the head, thereby adjusting the energy density by increasing / decreasing the irradiation area of the deflection irradiation unit according to the processing conditions. it can.
Further, by using a prism having a curved laser light transmission surface or using a convex lens as an optical member, the energy density can be increased by narrowing the laser light to be deflected.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, laser processing methods and laser processing apparatuses according to first to fourth embodiments of the present invention will be described with reference to the drawings. In each embodiment, the same reference numerals are given to the common components, and the description thereof is omitted.
(First embodiment)
FIG. 1 shows a laser processing apparatus for performing laser processing by the laser processing method of the present embodiment.
As shown in the figure, the laser processing apparatus 11A has a laser oscillator 12 using a laser diode (LD) as an oscillation source, and a head 14 that guides and condenses the laser light from the laser oscillator 12 through an optical fiber 13. doing. It is also possible to adopt a configuration in which the laser beam from the laser oscillator 12 is directly condensed by the head 14 without using the optical fiber 13.
[0016]
The head 14 has an optical system 15 that deflects and narrows down the laser light from the laser oscillator 12. The head 14 irradiates the laser light narrowed down by the optical system 15 from a nozzle 16 and is installed on a table (not shown). The workpiece W which is moved relative to the workpiece 14 is irradiated, and the workpiece W is subjected to processing such as welding.
[0017]
The head 14 has a prism (optical member) 21 that deflects part of the laser light from the nozzle 16.
This prism 21 is irradiated with a part of the laser light emitted from the nozzle 16. The irradiated laser light is deflected by the prism 21 and irradiated so as to be superimposed on the irradiation position of the remaining laser light that exits the nozzle 16 and does not pass through the prism 21.
As shown in FIG. 2, a moving mechanism 23 for moving the laser oscillator 12 and the head 14 and the table relative to each other is connected to the control unit 22 of the laser processing apparatus 11A. The mechanism 23 is controlled according to the processing conditions.
[0018]
According to the laser processing apparatus 11A as described above, as shown in FIG. 3A, the laser beam irradiated to the groove of the workpiece W is irradiated with a substantially rectangular shape as usual unless the prism 21 is present. In contrast to the shape, by inserting the prism 21, the irradiation unit indicated by reference numeral S2 is deflected and superimposed on the irradiation unit S1 side that does not pass through the prism 21, as shown in FIG. 3B. Thereby, the laser light from the nozzle 16 is deflected by the prism 21 to the irradiation part S1 (hereinafter, this part is referred to as the direct irradiation part S1) where the laser light from the nozzle 16 is directly irradiated without passing through the prism 21. The irradiation unit S2 (hereinafter, this portion is referred to as a deflection irradiation unit S2) is formed into a substantially square shape, and the energy density is significantly increased.
[0019]
(Comparative example)
A comparison was made between the welding speeds of the conventional apparatus having a rectangular irradiation shape and the laser processing apparatus 11A of the above embodiment.
The welding speed when penetration butt welding a SS400 steel sheet having a thickness of 3 mm with an output of 4 KW was about 0.1 m / min in the conventional apparatus, but is 0 in the laser processing apparatus 11A of the present embodiment. The speed was increased to about 7 m / mim.
[0020]
In this way, part of the laser light from the head 14 is deflected and superimposed on the direct irradiation unit S1 that directly irradiates the workpiece W as the deflection irradiation unit S2, so that the energy density can be increased. Therefore, the laser oscillator 12 can be made compact, the absorption rate to various materials is high, the workability is good, and furthermore, the oscillation efficiency of the laser beam is extremely good, but the laser beam from the laser diode having a relatively low energy density is obtained. The energy density can be greatly increased to ensure excellent machining performance.
Further, by superimposing, the irradiation shape can be made close to a square shape, direction dependency during processing can be suppressed, and processing can be facilitated.
[0021]
(Second Embodiment)
As shown in FIG. 4, in the laser processing apparatus 11B, a prism 21 is provided with a drive mechanism 24. The drive mechanism 24 swings the prism 21 around a rotation axis parallel to the processing direction.
[0022]
As shown in FIG. 5, the drive mechanism 24 is connected to the control unit 22 of the laser processing apparatus 11 </ b> B, and the control unit 22 controls the drive mechanism 24 together with the laser oscillator 12 and the moving mechanism 23.
And according to this laser processing apparatus 11B, when welding the groove | channel of the workpiece W, the deflection | deviation irradiation part S2 deflect | deviated by the prism 21 is made to rock | fluctuate the prism 21, and the machining direction along a groove | channel is carried out. Can be reciprocated in a direction perpendicular to the direction.
[0023]
Thereby, for example, since the groove is wider than the direct irradiation part S1, even when the direct irradiation part S1 passes through the groove, as shown in FIGS. 6A and 6B, the processing direction The groove is sufficiently melted by the deflecting irradiation unit S2 that reciprocates in a direction orthogonal to the direction, and welding can be reliably performed. With such a configuration, the tolerance for the groove gap can be increased.
The movement of the deflecting irradiation unit S2 due to the swing of the prism 21 is controlled by the control unit 22 controlling the driving of the driving mechanism 24 according to the size of the gap, the plate thickness, the material, and the like of the workpiece W to be welded. It is performed with an appropriate period and moving distance.
[0024]
(Third embodiment)
As shown in FIG. 7, in the laser processing apparatus 11C, the drive mechanism 25 swings the prism 21 around a rotation axis that is orthogonal to the processing direction.
In the case of the laser processing apparatus 11C, when the groove of the workpiece W is welded, the deflection irradiation unit S2 deflected by the prism 21 is moved along the processing direction by swinging the prism 21. Can be made.
[0025]
Then, as shown in FIGS. 8A and 8B, the deflection irradiation unit S2 is welded while reciprocating in the direction along the processing direction, thereby adjusting the cooling rate of the molten metal immediately after welding and controlling the structure. In addition, bubbles in the metal immediately after welding can be removed by promoting stirring, and the quality of the welded portion can be improved.
Note that the movement of the deflecting irradiation unit S2 due to the swing of the prism 21 is appropriate when the control unit 22 controls the driving of the driving mechanism 25 according to the welding speed, the plate thickness, material, and the like of the workpiece W to be welded. With a long period and a moving distance.
[0026]
(Fourth embodiment)
As shown in FIG. 9, in this laser processing apparatus 11D, instead of the prism 21, a convex lens (optical member) 31 is provided inclined with respect to the optical axis, and a part of the laser light is deflected by the convex lens 31. As shown in FIG. 10, the deflected deflection irradiation unit S2 is directly superimposed on the irradiation unit S1.
And in this laser processing apparatus 11D, since the energy density of the deflection | deviation irradiation part S2 superimposed on the direct irradiation part S1 is further raised with the convex lens 31, welding by the laser beam of a still higher energy density is attained.
[0027]
Further, by making the convex lens 31 of the laser processing apparatus 11D movable along the irradiation direction of the laser beam, the irradiation area of the deflection irradiation unit S2 can be made variable.
That is, if the convex lens 31 is moved and the irradiation area of the deflection irradiation unit S2 is reduced as shown in FIG. 11A, processing with a higher energy density is possible. As shown in FIG. If the irradiation area of the deflection irradiation unit S2 is increased, a wide range of processing becomes possible.
[0028]
By applying the configuration as shown in the above embodiments, the following effects can be obtained.
The energy density of the laser beam can be increased, and DDL can be used even in situations where it has been difficult to use the laser beam.
-The tolerance of the groove gap can be increased.
・ Defects such as bubbles can be prevented and processing quality can be improved.
[0029]
In addition, the irradiation area of the deflection irradiation unit S2 may be varied by moving the prism 21 of the laser processing apparatuses 11A, 11B, and 11C along the optical axis direction of the laser light.
Further, the laser light transmission surface of the prism 21 may be curved so as to have a curvature and have the same light collecting effect as the convex lens 31.
In the above example, one prism 21 or convex lens 31 is provided. However, the number of the prisms 21 or convex lenses 31 is not limited to one, and a plurality of prisms 21 or convex lenses 31 may be provided as necessary. Of course.
Moreover, in the said embodiment, although laser processing apparatus 11A-11D demonstrated taking the example of performing a welding process, for example, at the time of brazing, a part of beam is made into material by polarizing a part of laser beam. The remainder can be used for heating and wire melting. Moreover, these laser processing apparatuses 11A-11D can perform various processes, such as a cutting process, surface processing, and build-up, not only a welding process. For example, at the time of cutting, it is possible to control the input energy density distribution according to the object to be cut. In addition, it is possible to control the overheating distribution in the melted part at the time of overlaying, and to prevent insufficient heating at the end of the overlay.
[0030]
【The invention's effect】
As described above, according to the present invention, a part of the laser beam is deflected and superposed on the direct irradiation unit that directly irradiates the workpiece as the deflection irradiation unit. As a result, the energy density of the laser light from the laser diode with extremely good laser light oscillation efficiency but relatively low output can be significantly increased, and excellent processing performance can be ensured. As a result, the laser oscillator can be made compact, the absorption rate to various materials is high, and the workability can be improved.
Further, by superimposing, the irradiation shape can be made close to a square shape, direction dependency during processing can be suppressed, and processing can be facilitated.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a laser processing apparatus for explaining a configuration of a laser processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a control block diagram showing a control system of the laser processing apparatus.
FIG. 3 is a plan view of a workpiece to be welded by a laser processing apparatus.
FIG. 4 is a schematic configuration diagram of a laser processing apparatus for explaining a configuration of a laser processing apparatus according to a second embodiment of the present invention.
FIG. 5 is a control block diagram showing a control system of the laser processing apparatus.
FIG. 6 is a plan view of a workpiece to be welded by a laser processing apparatus.
FIG. 7 is a schematic configuration diagram of a laser processing apparatus for explaining a configuration of a laser processing apparatus according to a third embodiment of the present invention.
FIG. 8 is a plan view of a workpiece to be welded by a laser processing apparatus.
FIG. 9 is a schematic configuration diagram of a laser processing apparatus for explaining a configuration of a laser processing apparatus according to a fourth embodiment of the present invention.
FIG. 10 is a plan view of a workpiece to be welded by a laser processing apparatus.
FIG. 11 is a plan view of a workpiece to be welded by a laser processing apparatus.
FIG. 12 is a schematic configuration diagram of a laser processing apparatus for explaining a configuration of a conventional laser processing apparatus.
FIG. 13 is a plan view of a workpiece to be welded by a laser processing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11A-11D ... Laser processing apparatus, 12 ... Laser oscillator, 14 ... Head, 21 ... Prism (optical member), 24 ... Drive mechanism, 31 ... Convex lens (optical member), S1 ... Direct irradiation part, S2 ... Deflection irradiation part, W ... Workpiece

Claims (9)

A laser processing method for performing processing by irradiating a workpiece with laser light from a laser diode,
A laser processing method, wherein a deflection irradiation unit for deflecting and irradiating a part of the laser beam is superimposed on a direct irradiation unit that directly irradiates the workpiece with the laser beam. The direct irradiation part of the laser beam is moved along the groove of the workpiece to perform welding on the workpiece, and the deflection irradiation part superimposed on the direct irradiation part is orthogonal to the processing direction. The laser processing method according to claim 1, wherein the laser processing method is reciprocated in a direction. A direction in which the direct irradiation part of the laser beam is moved along a groove of the workpiece to perform welding on the workpiece, and the deflection irradiation part superimposed on the direct irradiation part is along a processing direction. The laser processing method according to claim 1, wherein the laser processing method is reciprocally moved. A laser oscillator using a laser diode as an oscillation source;
A head for irradiating a workpiece with laser light from a laser diode of the laser oscillator;
An optical member that deflects the laser light emitted from the head so that the laser light emitted from the head is superimposed on a direct irradiation unit that is directly irradiated onto the workpiece;
A laser processing apparatus comprising: A moving mechanism that relatively moves the workpiece and the head, and the optical mechanism is arranged in one or both of a direction perpendicular to a moving direction of the head relative to the workpiece by the moving mechanism and a direction along the moving direction. 5. A laser processing apparatus according to claim 4, further comprising a drive mechanism for swinging the member. 6. The laser processing apparatus according to claim 4, wherein the optical member is movable along an optical axis direction of laser light emitted from the head. The laser processing apparatus according to claim 4, wherein a prism is used as the optical member. 8. The laser processing apparatus according to claim 7, wherein a transmission surface of the laser beam in the prism is curved. The laser processing apparatus according to claim 4, wherein a convex lens is used as the optical member.

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