JPH05329679A - Method and device for laser beam machining - Google Patents

Abstract

PURPOSE:To effectively remove melted and evaporated material by controlling the resultant direction of assisting gases, which are jected from a laser machining head and a front nozzle, in the direction of the streak trace of the melting part of a workpiece. CONSTITUTION:The front nozzle 15 is controlled to be always positioned in front in the advancing direction of the cutting of the laser machining head 1. The rotating direction is controlled with a small diameter gear, which is engaged with a gear 21 on a rotary cylindrical body 5, and a servo motor 23. The inclined angle of the nozzle 15 may be controlled with a pinion 19, which is engaged with the rack 11R of a nozzle support 11, and a servo motor 17. The inclination angle of the front nozzle 15 is experimentally determined through the thickness of the workpiece W, material, cutting speed, gas flow rate, weight flow rate (pressure), laser output, etc., as well as the inclination angle of the tangent line at a prescribed position in a curved streak trace, and stored in a data base; and, by controlling the inclination angle of the front nozzle 15 based on this data base the resultant vector C may be set along the curved streak trace M.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and apparatus, and more particularly to a laser processing method capable of cutting a workpiece at a higher speed and an apparatus used for the method.

[0002]

2. Description of the Related Art Conventionally, when a laser beam is radiated from a laser processing head onto a work to perform cutting of the work, an assist gas is jetted from the laser processing head at the same time as the laser beam. This assist gas has various functions such as protecting the processed lens in addition to the function of promptly removing the melted material and the evaporated material generated during the cutting processing.

[0003]

When cutting a work by laser processing, if the cutting speed is made higher,
When the dross adheres to the back surface of the work and curved streaks are generated on the cut surface, and when the cutting speed is further increased, the laser beam does not penetrate the work and cannot be cut.

Since it is not preferable that the dross adheres to the back surface of the work as described above, various means have been adopted to prevent the dross from adhering.

For example, there is a configuration in which a rear nozzle is arranged behind the laser processing head in the relative cutting direction, and the assist gas is jetted from this rear nozzle to the cutting position of the work. The target injection position of the assist gas from the rear nozzle is a cutting surface slightly below the upper surface of the work.
According to this configuration, the adhesion of dross is reduced as compared to the case where the rear nozzle is not used, but the assist gas injected from the rear nozzle is in a direction (cutting surface) that blocks the gas flow of the assist gas injected from the laser processing head. Is not desirable because it acts in the direction that intersects the streak in the fusion zone that occurs in 1).

[0006]

In view of the conventional problems as described above, the present invention provides a laser beam from a laser processing head to a work to cut the work.
The flow direction of the assist gas ejected from the laser processing head or the flow direction of the assist gas ejected from the front nozzle arranged in front of the relative cutting advancing direction of the laser processing head or the combined direction of the both assist gas flows. Is controlled in a direction substantially along the curved streak generated on the cut surface of the work to perform the cutting process.

Further, a front nozzle for injecting an assist gas near the laser processing position of the work is arranged and provided in front of the relative cutting direction of the laser processing head for irradiating the work with a laser beam. The tilt angle of the front nozzle is controlled based on the plate thickness of the workpiece, the material, the cutting speed, the flow rate or pressure of the assist gas, and the preset data table. Is.

[0008]

With the above construction, the flow direction of the assist gas ejected from the laser processing head and the front nozzle is along the striations of the melted portion formed on the cut surface, and the melted material and the evaporated material generated during the cutting work are It can be easily blown off in the direction along the streak. In this case, the combined vector of the assist gas ejected from the laser processing head and the assist gas ejected from the front nozzle becomes large, and the melted material or the evaporated material can be removed more effectively.

Therefore, the adhesion of dross to the back surface of the work is reduced, the area of the cutting surface of the work is always in a clean state, the laser beam is absorbed more effectively, and the cutting speed is improved. The speed can be increased.

[0010]

EXAMPLES Referring to FIG. 1, a work W to be cut and processed.
The laser processing head 1 for irradiating the laser beam LB to
It is provided so as to be movable relative to the work W in the X, Y, and Z axis directions. Since the structure for moving the laser processing head 1 relatively in the X, Y, and Z axis directions is well known, its detailed description is omitted.

A rotary cylinder 5 is rotatably supported by a support body 3 of the laser processing head 1. Under the rotary cylinder 5, an assist gas is supplied to the work W at the same time as the laser beam LB. A main nozzle 7 for jetting is provided. Further, the rotary cylinder 5 is provided with a supporting portion 9 having a quadrangular outer shape, and the supporting portion 9 has a desired position O on the axial center of the laser beam LB below the tip of the main nozzle 7. An arc-shaped nozzle support 11 centered on is supported movably via a plurality of support rollers 13.

The nozzle support 11 appropriately supports a front nozzle 15 located on the front side in the relative cutting direction of the laser processing head 1 (rightward in FIG. 1). The front nozzle 15 injects the assist gas toward the position O or the vicinity of the laser processing position of the work W.

In order to adjust the inclination angle of the front nozzle 15, a rack 11R is formed on the nozzle support 11, and the rack 11R is rotationally driven by a servo motor 17 mounted on the support portion 9. The pinion 19 is meshed. Therefore, the tilt angle of the front nozzle 15 can be arbitrarily controlled by appropriately controlling and driving the servo motor 17.

A gear 21 is provided on the outer peripheral surface of the rotary cylinder 5 in order to always position the front nozzle 15 on the front side in the relative cutting direction of the laser processing head 1. The gear 21 has a gear 21. A small-diameter gear 25 rotated by a servomotor 23 mounted on the support body 3 is meshed.

Therefore, by appropriately controlling the servo motor 23 in accordance with the relative cutting progress of the laser processing head 1, the front nozzle 15 can be controlled so as to be always positioned on the front side in the cutting progress direction.

It is desirable that the front nozzle 15 be provided so that the inclination angle with respect to the nozzle support 11 can be adjusted.

In the above structure, when the laser processing head 1 is moved relative to the work W in the X, Y, and Z axis directions to perform the cutting work of the work W, the laser processing head 1 is relatively moved. By appropriately controlling the servo motor 23 according to the cutting direction, the front nozzle 15
Can always be positioned on the front side in the cutting direction. Further, the tilt angle of the front nozzle 15 can be arbitrarily controlled by controlling and driving the servo motor 17 to appropriately move the nozzle support 11.

That is, as shown in FIG. 2, a dynamic pressure vector A based on the gas velocity of the assist gas injected from the main nozzle 7 and a dynamic pressure vector B based on the gas velocity of the assist gas injected from the front nozzle 15. The direction of the composite vector C can be controlled so as to be substantially along the striation M of the melted portion (which becomes a curved striation when the cutting speed increases) generated on the cut surface of the work W.

At this time, the plate thickness, material, cutting speed, gas flow rate, flow rate (pressure), laser output and the like of the work W and a predetermined position of the curved striation (for example, near the upper surface or the lower surface of the work or near the middle of the plate thickness). ), The inclination angle of the tangent line is experimentally obtained in advance and stored in a database, and by controlling the inclination angle of the front nozzle 15 based on this database, the composite vector C can be made to substantially follow the curved striation M. You can

The combined vector C is usually larger than the dynamic pressure vectors A and B, and even if the flow velocity of the assist gas injected from the main nozzle 7 and the front nozzle 15 is not relatively high. , It is possible to quickly remove the melted material and evaporated material generated during cutting,
Adhesion of dross to the back surface of the work W can be reduced, and the cutting speed can be increased.

Regarding the reduction of dross adhesion, the main nozzle 7
It is also possible to reduce the adhesion of dross by increasing the pressure of the assist gas injected from the device, but in this case, it is necessary to protect the condenser lens for condensing the laser beam LB from the high pressure. However, in the present embodiment, even if the inclination angle of the front nozzle 15 is controlled and the assist gas injected from the front nozzle 15 is made to have a higher pressure, a problem may occur in which the condenser lens is affected. In other words, dross adhesion can be effectively prevented.

That is, according to this embodiment, it is possible to effectively prevent dross from adhering even when the work W is cut at a higher speed.

FIG. 3 shows a second embodiment, which is the same as the first embodiment.
The components having the same functions as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the second embodiment, the nozzle support 11 is mounted on the support portion 9 so as to be movable in the vertical direction, and the front nozzle 15 is pivotally attached to the lower portion of the nozzle support 11 so that the inclination angle can be adjusted. is there.

That is, according to this structure, the front nozzle 15 can be vertically adjusted through the nozzle support 11 by controlling and driving the servo motor 17, and the servo motor 27 mounted on the nozzle support 11 can be appropriately adjusted. By controlling and driving, the pivot shaft (not shown) of the front nozzle 15 can be rotated, and the inclination angle of the front nozzle 15 can be adjusted.

Also in the second embodiment, the same effect as that of the first embodiment can be obtained.

FIG. 4 shows a third embodiment. In the first and second embodiments, the case where the rotary cylinder 5, the main nozzle 7 and the like are rotated by the servo motor 23 has been described. The third embodiment is a case where the main nozzle 7 is non-rotatable and fixed.

In the third embodiment, when the main nozzle 7 moves relative to the work W in the X and Y axis directions, the front nozzle 15 is always positioned on the front side in the traveling direction. Turntable 2 on the straight part 7S of 7
9 is horizontally rotatably mounted. The front nozzle 15 is pivotally attached to a bracket provided on the front side (right side in FIG. 4) of the lower surface of the turntable 29 so that the tilt angle can be adjusted, and the tilt angle of the front nozzle 15 can be adjusted. An actuator 31 such as a cylinder is attached.

More specifically, in this embodiment, a pinion 33 is attached to a pivot shaft that pivotally supports the front nozzle 15, and a rack 35 reciprocated by the actuator 31 meshes with the pinion 33. is there.
Therefore, by appropriately controlling the actuator 31, the inclination angle of the front nozzle 15 can be arbitrarily adjusted. A servo motor can be used as an actuator that adjusts the inclination of the front nozzle 15.

A leg member 37 extending to the upper surface of the work W is attached to the rear side (left side in FIG. 4) of the turntable 29, and the lower surface of the leg member 37 rolls on the upper surface of the work W. A free roller 39 is rotatably mounted.

With the above construction, in the third embodiment, the roller 39 always follows the relative movement of the main nozzle 7 in the X and Y axis directions, and the front nozzle 15 is always in the relative direction. It is located on the front side in the cutting proceeding direction, and this embodiment can also achieve the same effect as the above-mentioned embodiment.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making various modifications. For example, the roller 39 and the like in the third embodiment may be omitted and the rotary disk 29 may be controlled to rotate by using a servomotor.

[0033]

As will be understood from the above description of the embodiments, according to the present invention, the front nozzle 15 is always located at the front side in the relative cutting advancing direction, and the inclination angle of the front nozzle 15 is adjusted. By doing so, the gas flow of the assist gas can be directed along the curved streak at the cutting position, and the melted material or evaporated material generated during the cutting process can be effectively removed. Therefore, the adhesion of dross can be prevented and the cutting speed can be increased.

[Brief description of drawings]

FIG. 1 is a side view illustrating an apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a gas flow of assist gas and a curved striation generated in a work.

FIG. 3 is a side view of an apparatus showing a second embodiment.

FIG. 4 is a side view of an apparatus showing a third embodiment.

[Explanation of symbols]

 1 Laser processing head 7 Main nozzle 15 Front nozzle W work

Claims (3)

[Claims] 1. When cutting a workpiece by irradiating the workpiece with a laser beam from the laser processing head, the flow direction of the assist gas ejected from the laser processing head or the relative cutting progress direction of the laser processing head is measured. Cutting is performed by controlling the flow direction of the assist gas ejected from the front nozzle arranged on the front side or the combined direction of the flows of the both assist gases so as to be substantially along the curved striations formed on the cutting surface of the work. A laser processing method characterized by the above. 2. A front nozzle for injecting an assist gas near the laser processing position of the work is arranged and provided in front of a relative cutting direction of a laser processing head for irradiating the work with a laser beam, and the front nozzle is provided. A laser processing apparatus characterized in that the inclination angle of the laser beam is adjustable. 3. The inclination angle of the front nozzle is configured to be controlled on the basis of a preset data table based on the work thickness, material, cutting speed, assist gas flow rate or pressure. The laser processing apparatus according to claim 2.