JP3131288B2 - Laser processing method and apparatus - 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 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 irradiated from a laser processing head onto a work to cut the work, an assist gas is simultaneously injected from the laser processing head with the laser beam. The assist gas has various functions such as protecting a processed lens, in addition to a function of quickly removing a melt or an evaporant generated during the cutting processing.

[0003]

When a workpiece is cut by laser processing, if the cutting speed is made higher,
The dross adheres to the back surface of the work, and a curved streak is formed on the cut surface. If the cutting speed is further increased, the laser beam cannot penetrate the work and cannot be cut.

[0004] As described above, it is not preferable that dross adhere to the back surface of the work, and various means are employed to prevent the dross from adhering.

For example, there is a configuration in which a rear nozzle is disposed behind a laser processing head in a relative cutting direction, and an assist gas is injected from the rear nozzle to a cutting position of a work. The target injection position of the assist gas from the rear nozzle is a cut surface slightly lower than the upper surface of the work.
According to this configuration, although the dross adhesion is reduced as compared with a case where the rear nozzle is not used, the assist gas ejected from the rear nozzle is directed in a direction (cut surface) in which the gas flow of the assist gas ejected from the laser processing head is cut off. In the direction intersecting with the streaks of the melted portion generated at the same time).

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method for cutting a workpiece by irradiating a laser beam from a laser processing head to the workpiece.
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 disposed in front of the relative cutting direction of the laser processing head, or the combined direction of the flows of the two assist gases Is controlled in a direction substantially along a curved streak generated on a cut surface of the work to perform a cutting process.

In addition, a front nozzle for injecting an assist gas near the laser processing position of the work is arranged and provided in front of a laser processing head for irradiating the work with a laser beam in a relative cutting direction. In the laser processing device that is provided so that the inclination angle of the work can be adjusted, the work thickness, material, cutting speed, gas flow rate, flow rate,
A database indicating the relationship between the laser output and the inclination angle of the tangent at a predetermined position of the curved streak generated on the cut surface of the work, wherein the flow direction of the assist gas ejected from the laser processing head and the ejected gas from the front nozzle The tilt angle of the front nozzle is controlled based on the database so that the combined direction with the flow direction of the assist gas is substantially along the curved line formed on the cut surface of the work.

[0008]

According to the above configuration, the flow direction of the assist gas injected from the laser processing head and the front nozzle is in the direction along the streaks of the molten portion generated on the cut surface, and the molten material and the evaporate generated during the cutting process are removed. 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, so that the melt and the evaporant can be more effectively removed.

Therefore, the dross adheres to the back surface of the work, and the area of the cut surface of the work is always in a clean state, so that the laser beam can be absorbed more effectively, and the cutting speed is reduced. Higher speed can be achieved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG.
The laser processing head 1 for irradiating the laser beam LB to the
The workpiece W is provided so as to be relatively movable in the X, Y, and Z axis directions. The configuration for relatively moving the laser processing head 1 in the X, Y, and Z axis directions is well-known, and thus the detailed description thereof is omitted.

A rotary cylinder 5 is rotatably supported on the support main body 3 of the laser processing head 1. An assist gas is supplied to the work W at the lower portion of the rotary cylinder 5 simultaneously with the laser beam LB. A main nozzle 7 for jetting is provided. The rotary cylinder 5 is provided with a support portion 9 having a rectangular outer shape. The support portion 9 has a desired position O on the axis of the laser beam LB at a position below the tip of the main nozzle 7. 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 (to the right in FIG. 1). The front nozzle 15 injects an assist gas toward the position O or near the laser processing position of the work W.

In order to adjust the angle of inclination of the front nozzle 15, a rack 11R is formed on the nozzle support 11, and the rack 11R is rotated by a servomotor 17 mounted on the support portion 9. The pinion 19 is engaged. 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 in front of the relative cutting direction of the laser processing head 1. A small-diameter gear 25 rotated by a servomotor 23 mounted on the support body 3 is meshed.

Therefore, by appropriately controlling the servomotor 23 in accordance with the relative cutting progress of the laser processing head 1, the front nozzle 15 can be controlled so as to always be located 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 configuration, when the laser processing head 1 is relatively moved in the X, Y, and Z-axis directions with respect to the workpiece W to perform the cutting of the workpiece W, the relative position of the laser processing head 1 is reduced. 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. In addition, 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 flow rate of the assist gas injected from the main nozzle 7 and a dynamic pressure vector B based on the gas flow rate of the assist gas injected from the front nozzle 15 are shown. The direction of the composite vector C can be controlled in a direction substantially along the streaks M of the melted portion generated on the cut surface of the workpiece W (they become curved as the cutting speed increases).

At this time, the thickness, material, cutting speed, gas flow rate, flow rate (pressure), laser output and the like of the work W and the predetermined position of the curved streak (for example, near the upper surface or lower surface of the work or near the middle of the plate thickness) The angle of inclination of the tangent in (1) is experimentally determined in advance and is made into a database, and by controlling the angle of inclination of the front nozzle 15 based on this database, the combined vector C is made to substantially follow the curved line M. Can be.

The composite vector C is usually larger than the dynamic pressure vectors A and B. Even when the flow velocity of the assist gas injected from the main nozzle 7 and the front nozzle 15 is not relatively large, , It can quickly remove the melt and evaporate generated during the cutting process,
Adhesion of dross to the back surface of the work W can be reduced, and the cutting speed can be further increased.

Regarding the reduction of dross adhesion, the main nozzle 7
It is also possible to reduce the dross adhesion by increasing the assist gas injected from the nozzle to a higher pressure, but in this case, a configuration is necessary to protect the condenser lens that collects 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 set to a higher pressure, a problem may occur that affects the condenser lens. And dross adhesion can be effectively prevented.

That is, according to this embodiment, the dross can be effectively prevented from being attached even when the workpiece W is cut at a higher speed.

FIG. 3 shows a second embodiment.
The components having the same functions as those of the embodiment are denoted by the same reference numerals, and the description is 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 a front nozzle 15 is pivotally mounted on the lower portion of the nozzle support 11 so that the inclination angle can be adjusted. is there.

That is, according to this configuration, the position of the front nozzle 15 can be adjusted up and down via the nozzle support 11 by controlling and driving the servo motor 17, and the servo motor 27 attached to 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.

In the second embodiment, the same effects as in 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 servomotor 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 main nozzle 7 is positioned so as to be always located on the front side in the traveling direction. Turntable 2 on straight part 7S of 7
9 is mounted to be freely rotatable horizontally. The front nozzle 15 is pivotally mounted on a bracket provided on the front side (the right side in FIG. 4) of the lower surface of the rotary disk 29 so that the tilt angle can be adjusted, and a bracket for adjusting the tilt angle of the front nozzle 15 is provided. An actuator 31 such as a cylinder is mounted.

More specifically, in this embodiment, a pinion 33 is attached to a pivot supporting 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. Note that a servo motor can be used as an actuator for adjusting 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 rotary disk 29. The lower surface of the leg member 37 rolls the upper surface of the work W. A free roller 39 is rotatably mounted.

With the above configuration, 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 always keeps the relative movement. It is located on the front side in the cutting progress direction, and in this embodiment, the same effect as in the above embodiment can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, but can be implemented in still other modes by making various changes. For example, it is also possible to omit the rollers 39 and the like in the third embodiment and to control the rotation of the turntable 29 using a servomotor.

[0033]

As will be understood from the above description of the embodiment, according to the present invention, the front nozzle 15 is always located on the front side in the relative cutting direction and the inclination angle of the front nozzle 15 is adjusted. By doing so, it is possible to direct the gas flow of the assist gas along the curved streaks at the cutting position, and it is possible to effectively remove a melt or an evaporant generated during the cutting process. Therefore, the dross can be prevented from adhering and the cutting speed can be further increased.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a gas flow of an assist gas and a curved streak generated on a workpiece.

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

FIG. 4 is an explanatory 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 (2)

(57) [Claims] When cutting a workpiece by irradiating a laser beam from the laser processing head to the work, the flow direction of the assist gas ejected from the laser processing head or the relative cutting progress direction of the laser processing head. Cutting is performed by controlling the flow direction of the assist gas ejected from the front nozzle disposed on the front side or the combined direction of the flows of the two assist gases in a direction substantially along a curved streak generated on the cut surface of the work. A laser processing method characterized by the above-mentioned. 2. A front nozzle, which injects an assist gas near a laser processing position of the work, is provided in front of a laser processing head for irradiating the work with a laser beam in a relative cutting direction. In the laser processing device provided with an adjustable inclination angle of the workpiece, the thickness of the workpiece, the material, the cutting speed, the gas flow rate, the flow rate, the laser output and the inclination angle of the tangent at a predetermined position of the curved streak generated on the cut surface of the workpiece With a database showing the relationship with
The database is such that the combined direction of the flow direction of the assist gas ejected from the laser processing head and the flow direction of the assist gas ejected from the front nozzle is substantially along the curved streak generated on the cut surface of the work. A laser processing apparatus configured to control a tilt angle of the front nozzle based on the laser beam.