JPH02160190A - Method and device for pierce-working in laser beam machine - Google Patents

Abstract

PURPOSE:To shorten the pierce time in a short time, and also, to execute stable pierce working by allowing a condensing lens to ascend or descend against a work so that a focal position of the condensing lens which is set in advance is varied in the depth direction of the work. CONSTITUTION:A focal distance of a condensing lens 37 corresponding to a kind and thickness of a work W is determined in advance, and the condensing lens 37 corresponding to its focal distance is held by a lens holder 35. Subsequently, when the working surface of the work W is irradiated by a laser beam LB, pierce-working to the work W is started. When the condensing lens 37 is allowed to descend successively, the work W is pierced and working is ended. In such a way, at the time of executing pierce-working to the work W, as pierce-working advances, by allowing the condensing lens 37 to descend, while controlling it by a descending position and a speed determined in advance, stable pierce-working is executed, and also, pierce-working can be executed at a high speed and in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) This invention relates to a piercing method and apparatus for a laser beam machine.

(Prior Art) Generally, when cutting a workpiece with a laser beam machine, it is necessary to pierce the workpiece in advance.

Conventionally, in the piercing process in which a workpiece is pierced using a laser processing machine, the focal length of a condensing lens is selected in advance according to the type and thickness of the workpiece to be processed, and the selected condensing lens is attached to a lens holder. to hold. A laser beam is focused by a condensing lens held by this lens holder, and is irradiated onto the processing surface of a workpiece to pierce the workpiece.

(Problem to be Solved by the Invention) By the way, in the conventional piercing method described above, the focal position of the laser beam focused by the condensing lens is determined by the lens holder that holds the condensing lens being fixedly provided. Because of this, the piercing process is performed while maintaining a fixed position in the middle shrine of the piercing process. Therefore, when the focus position of the focusing lens is set on the processing surface of the workpiece to be processed, the power density of the laser beam is high at the beginning of the piercing process, and the piercing process is good, but as the piercing process progresses, the laser beam becomes It spreads, the power density decreases, and piercing cannot be said to be good.

As a result, when piercing a workpiece with a thickness of 6 mm or more, for example, there is a problem in that it takes a considerable amount of time to pierce, and by extension, it takes a long time to cut the workpiece. There was a problem.

Additionally, if the piercing takes a long time, the cutting process may start before the piercing is completely completed, resulting in poor cutting and damage to the nozzle.

The purpose of the present invention is to improve the above-mentioned problems by providing a piercer in a laser processing machine that can shorten the piercing time and perform stable piercing when piercing a workpiece, particularly a thick workpiece. An object of the present invention is to provide a processing method and an apparatus therefor.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention pierces the workpiece by irradiating the workpiece with a laser beam focused by a condensing lens. This is a piercing method for a laser beam machine in which a focusing lens is raised or lowered relative to a workpiece in order to change a preset focal position of a focusing lens in the depth direction of the workpiece to pierce a workpiece.

The present invention also provides a laser processing machine that pierces a workpiece by irradiating the workpiece with a laser beam focused by a condensing lens, and a nozzle that directs the laser beam toward the processing surface of the workpiece. A piercing device for a laser processing machine is provided in which a nozzle device is provided to maintain a constant distance between the tip position of the lens and the processing surface of the workpiece, and a lens holder holding the condensing lens is provided in the nozzle device so as to be movable up and down. was configured.

(Function) By adopting the piercing method and device for the laser processing machine of the present invention, the distance between the tip position of the nozzle that directs the laser beam toward the processing surface of the workpiece and the processing surface of the workpiece can be kept constant. A holding device (nozzle device) is provided. A lens holder holding a condensing lens is provided on this nozzle device so as to be movable up and down.

Therefore, by raising or lowering the lens holder relative to the processing surface of the workpiece,
During the piercing process, the focal position of the condensing lens changes in the depth direction of the workpiece, so the piercing process is performed stably, at high speed, and in a short time.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Referring to FIG. 3, the base 3 in the laser processing machine
A work table 5 on which a work W is placed is provided above. On the base 3, there is a guide 9 for guiding the X-axis carriage 7, which is gate-shaped when viewed from the right side in FIG. 3, in the left-right direction (hereinafter referred to as the X-axis direction).
Extended to and established.

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That is, the X-axis carriage 7 is guided by the guide 9 by a drive device (not shown) and moved in the X-axis direction. A telescopic cover 11 is provided behind the base 3.

The upper part of the X-axis carriage 7 has a direction perpendicular to the plane of the drawing in FIG. 3 (hereinafter referred to as the Y-axis direction).

) is provided with a movable Y-axis gear ledge 13.

Thus, the Y-axis gear ledge 13 is moved in the Y-axis direction with respect to the X-axis carriage 7 by a drive device (not shown).

In the front part of the Y-axis gear ledge 13 in FIG.
In the figure, a processing head 15 is provided that is movable in the vertical direction (hereinafter referred to as the Z-axis direction). A nozzle device 17 for irradiating the laser beam LB is attached to the lower part of the processing head 15. Therefore, processing head 1
5 is moved in the Z-axis direction with respect to the Y-axis gear ledge 13, and the position between the workpiece W and the nozzle device 17 is adjusted.

A box-shaped bed 19 is arranged near the left side of the base 3, and a laser oscillator 21 for oscillating a laser beam LB is provided on the bed 19. An overhead beam 23 is attached to the front of the laser oscillator 21.
The distal end portion of is connected to the processing head 15.

In the laser oscillator 21, for example, He, N2. A laser beam LB made of a C02 gas mixture is oscillated. The laser beam LB follows a path as shown by the two-dot chain line, passes through an external mirror (not shown) attached to the X-axis and Y-axis carriage 7゜13, and then passes through an external mirror attached to the upper part of the processing head 15. 25 and is irradiated from the nozzle device 17.

The laser beam LB irradiated from the nozzle device 17 is applied to the work W placed on the work table 5 together with an assist gas such as oxygen to perform predetermined laser processing.

In addition, when performing desired processing on the workpiece W, the processing head 15 is moved in the X-axis, Y-axis, and Z-axis directions to perform the processing.

On the work table 5, there are provided a plurality of work support columns 27 for supporting the work W when processing the work W, and a plurality of free bearing devices 29 for supporting the work W when the work W is loaded. .

The plurality of free bearing devices 29 protrude from the workpiece support column 27 and support the workpiece W when the workpiece W is carried in. When the workpiece W is supported and processed by the workpiece support column 27, the free bearing device 29 is in a position sunk below the workpiece support column 27. That is, the free bearing device 29 can freely move in and out of the workpiece support column 27.

A nozzle device 17 is provided at the bottom of the processing head 15, as shown in FIG.

This nozzle device 17 is comprised of a hollow cylindrical nozzle body 31 and a nozzle 33 that is integrally provided at the bottom of this nozzle body 31 and for irradiating the workpiece W with a laser beam LB.

A hollow lens holder 35 is provided in the upper portion of the nozzle body 31 of the nozzle device 17 so as to be slidable in the vertical direction. A condensing lens 37 is held at the lower part of the lens holder 35 . This lens holder 35
A male thread 35A is formed on the outer periphery.

On the other hand, a worm wheel 41 attached to the support member 39 is provided on the outside of the lens holder 35, and a female thread 41A is formed on the inner circumference of the worm wheel 41.

The female thread 41A of the worm wheel 41 and the male thread 35A of the lens holder 35 are screwed together. Further, a worm 43 is meshed with the worm wheel 41,
The worm 43 has a drive motor 45 such as a servo motor.
output shafts 47 are interlocked and connected. An NC device 49 that controls the laser processing machine 1 is connected to the drive motor 45 .

The distance H between the tip position of the nozzle 33 in the lens device 17 and the processing surface Wt of the workpiece W is always kept constant.

With the above configuration, the drive motor 45 is driven by a command based on the computer program stored in the NC device 49. When the drive motor 45 is driven, the worm 43 is rotated via the output shaft 47.

When the worm 43 is rotated, the lens holder 35 is lowered via the worm wheel 41, as shown in FIG. 1, for example, since the worm 43 and the worm wheel 41 are engaged with each other.

The lens holder 35 is lowered from the position indicated by the solid line to the position indicated by the two-dot chain line in FIG. 1, and the condenser lens 37 is simultaneously lowered from the position indicated by the solid line to the position indicated by the two-dot chain line.

Note that the lowering position and speed of the lens holder 35 are experimentally determined and controlled in advance according to the type and thickness of the workpiece W.

The operation of piercing the workpiece W will be explained based on FIG. 2. FIG. A condensing lens 37 matching the focal length is held in the lens holder 35. That is, the laser beam LB focused by the focusing lens 37 is irradiated onto the processing surface of the workpiece W.

At this time, the focal length of the laser beam LB is set to the processing surface of the workpiece W.

In FIG. 2(A), when the laser beam LB is irradiated onto the processing surface of the workpiece W, piercing processing on the workpiece W is started. When the workpiece W is pierced and the condensing lens 37 is lowered by a hair 1, the state shown in FIG.
The state shown in Figure (C) is reached. From the state shown in Fig. 2 (C), if the holder is further lowered by 3, as shown in Fig. 2 (D),
The workpiece W is pierced and the process ends.

In this way, when piercing the workpiece W, the lowering position is determined in advance as the piercing progresses.

By lowering the condensing lens 37 while controlling the speed, piercing can be performed more stably than in the past, and piercing can be performed at high speed and in a short time. This also eliminates cutting defects and nozzle damage.

Note that the present invention is not limited to the embodiments described above, and can be implemented in other embodiments by making appropriate changes. In this embodiment, the lens holder 35 holding the condensing lens 37 is provided above the workpiece W, and the lens holder 35 is lowered. It is also possible to provide a lens holder 35 holding the lens 37 and raise the lens holder 35.

Furthermore, although an example has been shown in which the lens holder 35 is lowered via a transmission member between a worm wheel and a worm, other transmission members such as a rack and pinion may be used.

[Effects of the Invention] As can be understood from the description of the embodiments above, according to the present invention, since the structure is as described in the claims, it is possible to stably pierce a workpiece. It can be carried out at high speed and in a short time. It is particularly effective for piercing workpieces with a thickness of, for example, 6III11 or more.

As a result, there will be no cutting defects or damage to the nozzle during cutting after piercing.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of the processing head, with some parts omitted, showing the main parts according to the present invention, and FIGS. FIG. 3 is a schematic side view of a laser processing machine according to an embodiment of the present invention. 1... Laser processing machine 15... Processing head 17.
... Nozzle device 31 ... Nozzle body 33 ... Nozzle 35 ... Lens holder 37 ... Condensing lens 45 ... Drive motor 49 ... NC device agent Patent attorney Yasuo Miyoshi

Claims (2)

[Claims] (1) When piercing a workpiece by irradiating the workpiece with a laser beam focused by a condensing lens, the condensing lens is used to change the preset focal position of the focusing lens toward the depth of the workpiece. A piercing method in a laser beam machine, characterized in that a laser beam is moved upward or downward relative to a workpiece to pierce the workpiece. (2) In a laser processing machine that pierces the workpiece by irradiating the workpiece with a laser beam focused by a condensing lens, the tip position of the nozzle that directs the laser beam toward the processing surface of the workpiece. A laser processing machine characterized in that a nozzle device is provided to maintain a constant distance from the processing surface of the workpiece, and a lens holder holding the condensing lens is provided in the nozzle device so as to be movable up and down. Piercing processing equipment.