JPH02220794A - Laser beam processing method - Google Patents

Abstract

PURPOSE:To easily execute the operations up to the start of normal cutting of a work in a short period of time by executing round hole machining while previously automatically moving a condenser lens upward and downward and automatically determining an optimum focus position with an automatic focus adjusting device. CONSTITUTION:The work W is first subjected to round hole machining several times while the condenser lens 33 is moved in a vertical direction at the time of cutting the work W with a laser beam machine 1. The area or diameter of the round hole is measured by the automatic focus adjusting device 21 at every processing. The condenser lens 33 is positioned to the position moved downward by 0.Xmm from the position of the condenser lens 33 in the smallest area or diameter among the measured areas or diameters of the round hole as the optimum focal position of the condenser lens 33 and thereafter, the normal cutting of the work W is started. The focusing of the condenser lens 33 is thereby easily, rapidly and exactly executed and, therefore, the operations up to the start of the normal cutting of the work W are easily carried out in a short period of time.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a laser processing method, and more specifically, the present invention relates to a laser processing method, and more specifically, a method for processing a round hole while moving a condensing lens up and down on a workpiece in advance. This invention relates to a laser processing method in which cutting is performed several times to determine the optimum focal position of a condensing lens, and then a regular workpiece is cut.

(Prior Art) Conventionally, a laser processing machine guides a laser beam output from a laser oscillator to a processing head, and focuses the laser beam with a condensing lens provided in the processing head. Cutting is performed by irradiating a workpiece with a focused laser beam.

Moreover, when cutting a workpiece with a laser beam machine, focusing is performed to bring the condenser lens to an optimal position. As a method for focusing the condenser lens, for example, a slit is cut into a piece of wood, and the narrowest point of the cut slit is set as the optimal focal point and detected.

Another method for focusing a condensing lens is to irradiate a laser beam onto an acrylic material and detect the optimum focal point at the deepest point cut into the acrylic material at the same output and irradiation time. .

(Problem to be Solved by the Invention) By the way, the former focusing method in the prior art described above requires wood for focus detection and is inaccurate because the focus position is detected visually. . Furthermore, the latter focusing method requires an expensive acrylic material for focus detection, and the vapor generated from the acrylic material has a problem in that it has an adverse effect on optical components such as condensing lenses and mirrors.

Furthermore, since both the former and latter focusing methods rely on the experience and intuition of engineers, focusing requires a lot of effort and time, and it is very troublesome until the proper cutting process begins. It was troublesome.

The purpose of the present invention is to improve the above-mentioned problems by easily, quickly, accurately and automatically focusing a condensing lens, thereby making it easier to start cutting a regular workpiece in a short time. It is an object of the present invention to provide a laser processing method that allows the laser processing to be carried out.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention includes cutting a workpiece by irradiating the workpiece with a laser beam focused by a condensing lens provided in a laser processing machine. When machining, drill a round hole in the workpiece several times while moving the condensing lens up and down, and each time measure the area or diameter of the round hole with an automatic focus adjustment device installed in the laser processing machine. Then, from the position of the condenser lens at the smallest area or diameter of the measured round hole, 0. This is a laser processing method in which the position moved by X mm is set as the optimum focus position of the condensing lens, and cutting is started on a regular workpiece.

(Function) By employing the laser machining method of the present invention, when cutting a workpiece with a laser beam machine, first, a round hole is machined several times in the workpiece while moving the condensing lens in the vertical direction. Then, when the round hole is machined several times, the area or diameter of the round hole is measured each time using an automatic focus adjustment device.

The position of the condenser lens moved downward from the position of the condenser lens at the smallest area or diameter of the measured round hole is set as the optimal focus position of the condenser lens, and then the condenser lens is positioned and then adjusted. It is designed to start cutting on a workpiece that has a certain shape.Therefore, it is easy to focus the condenser lens of the condenser lens.

Since it is quick, accurate, and automatic, operations up to the start of cutting on a regular workpiece can be performed easily 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. 4, a laser oscillator, such as a carbon dioxide laser oscillator, is provided on the rear side of the laser processing machine main body 3 of the laser processing machine 1. As shown in FIG. This laser oscillator is a general one and is configured to irradiate a laser beam in the direction of the laser processing machine main body 3.

A fixed table 5 is provided on the front side of the laser processing machine main body 3, and Y (not shown) is provided on both sides of the fixed table 5.
A side table 7 is provided that is movable in the Y-axis direction by a shaft drive motor MY.

A carriage base 9 is integrally provided on the side of the laser processing machine main body 3 of the side table 7, and the carriage base 9 has a carriage movable in the X-axis direction by an X-axis drive motor MX (not shown). 11 are provided. Furthermore, the carriage 11 is equipped with a plurality of work clamps 13 for clamping the work W.

An overhead beam 15 is horizontally supported in a cantilevered manner at the upper part of the front portion of the laser oscillator main body 3.

A processing head 17 is provided at the front of the overhead beam 15 and is movable in the X-axis direction by a Z-axis drive motor M2 (not shown). The processing head 17 is provided with a reflecting mirror and a condensing lens, the details of which will be described later.

With the above configuration, the laser beam output from the laser oscillator passes through the overhead beam 15, is bent by the reflection mirror in the rad 1f, is focused by the condensing lens, and is sent to the nozzle provided at the tip of the processing head. Kara work W
is irradiated. The workpiece W is clamped by the workpiece clamp 13, and the X-axis.

By moving in the Y-axis direction, cutting into a predetermined shape is performed.

One NC device for automatically numerically controlling the laser beam machine 1 is provided on the right side wall of the laser beam machine body 3. The laser processing machine 1 also includes an automatic focus adjustment device 21.
A CCD camera 23, which is a part of the automatic focus adjustment device 21 and is used to take an image of a round hole machined in the workpiece (sample) W, is located at the front right side of the laser processing machine main body 3. In addition, a light source 25 is provided directly below the CCD camera 23 in the fixed table 5. Further, near the laser processing machine 1, there is a part of an automatic focus adjustment device 21, which measures the area or diameter of a round hole machined in the workpiece (sample) W imaged by the CCD camera 23 and focuses the light. An image processing device 27 is arranged to automatically control the focus of the lens.

FIG. 1 shows a control block diagram of an automatic focus adjustment device 21 that automatically controls the focus of a condenser lens. 1st
In the figure, a reflecting mirror 29 is installed above the processing head 17 to reflect and bend the laser beam LB output from the laser oscillator. In addition, Rad 1 for processing
A sliding cylindrical member 31 that is non-rotatable and can freely slide up and down is mounted inside the housing, and inside this sliding cylindrical member 31 is a laser beam L bent by the two reflecting mirrors.
A condensing lens 33 for condensing B is provided. Furthermore, a nozzle 35 for irradiating the workpiece W with the laser beam LB focused by the condensing lens 33 is integrated at the tip of the sliding cylindrical member 31.

A male thread is formed on the outer periphery of the upper part of the sliding cylindrical member 31, and a gear 37 in which a female thread meshes with the male thread is rotatably supported by the sliding cylindrical member 31.

Another gear 39 is meshed with this gear 37, and a drive motor ML is interlocked with this gear 39.

With the above configuration, when the drive motor ML is driven, the sliding cylindrical member 31 is slid in the vertical direction via the gears 39 and 37, and the condensing lens 33 provided inside the sliding cylindrical member 31 is also moved in the same manner. The focus position is adjusted by moving in the direction.

Furthermore, in FIG. 1, the NC device 19 for numerically controlling the laser processing machine 1 is connected to the X
A shaft drive motor Mx, a Y-axis drive motor MY, and a Z-axis drive motor M2 are connected. Further, the autofocus control section 43 of the image processing device 27 is connected to the NC device 19,
A lens driving section 45 for driving the drive motor ML and an imaging processing section 47 for outputting an imaging command to the CCD camera 23 are connected to the automatic focus control section 43 .

An image processing section 49 is connected to this imaging processing section 47 .

With the above configuration, the NC device 19 outputs the axis drive command S, (1 is X+Y+Z) to the axis drive unit by setting the automatic focus adjustment program, and also outputs the operation command Q to the automatic focus control unit 43. It can be output.

That is, the workpiece (sample) W shown in FIG. 2 is clamped to the workpiece lamp 13 shown in FIG. 4, and after lowering the processing head 17 by driving the Z-axis drive motor MX, the automatic focus adjustment process can be migrated. In the automatic focus adjustment process of this example, the tip of the nozzle 35 is moved in the X-axis and Y-axis directions by driving the X-axis drive motor MX and Y-axis drive motor MY, and the focusing lens is placed on the workpiece (sample) W. The laser beam LB focused at 33 is used to actually process the circular holes w, w2, w3, . . . in sequence.

Next, when cutting the workpiece W, the operations from focusing the condensing lens 33 to actually starting the regular cutting will be explained based on the flowchart shown in FIG. 3.

In FIG. 3, in step S1, a workpiece (sample) W
is clamped to the workpiece clamp 13, an automatic focus adjustment program is set in the NC device 19 in step S2, and a command to machine a round hole in the workpiece (sample) W is output in step S3.

Here, a control command Q is output from the NC device 19 to the automatic focus control section 43, and a control command Q is outputted from the NC device 19 to the automatic focus control section 43.
Lens drive commands H, (i-1, 2, 3, . . . ) are output to move the lens to a preset initial position.

Therefore, in step S3, the round hole W shown in FIG.
1, 2, 3, ..., currently 1-1) are actually processed.

In step S4, after moving the CCD camera 23 above the round hole W1, the automatic focus control section 43
Further, the imaging processing unit 47 outputs the imaging command Pl to the CCD camera 23, the CCD camera 23 images the round hole W1, and based on this imaging signal A, the image processing unit 49 Measure the area D+ (D-t) of the hole W.

Next, in step S5, the condensing lens 33 is lowered by a certain unit amount by driving the drive motor ML, and the next round hole W, (i-
2) is processed, and in step S7, the area is measured and (D,) is measured.

In step S8, the area of the round hole D1 is increased, -,>D, .
If D,1>-D, the process returns to step S5 and D,-,<D.

If so, proceed to step S9. In step S9, the drive motor ML is driven to raise the condenser lens 33 by two units. In step S10, the workpiece W is moved in the Y-axis direction to perform round hole W+ machining, and in step Sll, the area DI is
(D-++) is measured.

In step S12, the area of the round hole D1 is D all>
Determine whether D a-1, D, +1>
If D a -1, return to step S9 and D
If a+l<Da-1, the process advances to step 813. In step S13, the drive motor ML is driven to remove the condenser lens 3.
3 is lowered by one unit, and in step S14, the workpiece W is moved in the Y-axis direction to machine the round hole W1. In step S15, the area of the round hole W is +2 using the same method as above.
Measure.

In step S16, the area of the round hole W1 is Dfi+□〉D
D, determines whether it is ell or not. 2〉Df
If l+1, the process proceeds to step S17, in which the condenser lens 33 is positioned at a position in the area of D,+1, and in step S18, the drive motor ML is driven to turn the condenser lens 33 into o.
, x"', for example, by 0.5ffi", and this position is set as the optimal focal position of the condensing lens 33, and N is set in step S19.
A cutting program for cutting the regular workpiece W is set in the C device 19, and the cutting process on the regular workpiece W is started and completed.

If Da+2 < D fill in step S16, the process proceeds to step S20, where the condenser lens 33 is positioned at a position with an area of +2, and step S18. The processing of S19 is performed and the process ends.

In this way, in this example, the condenser lens 3 is attached to the workpiece (sample) W.
3 is automatically moved up and down, and the focusing lens 33 is automatically focused easily, quickly, and accurately. Then, the cutting process on the regular workpiece W is started. The operation up to the start is easy and can be done in a short time.

Note that this invention is not limited to the embodiments described above, and can be implemented in other forms by making appropriate changes. For example, in this embodiment, the round hole W1 was measured in terms of area, but it is also applicable to measure the diameter.

[Effects of the Invention] As can be understood from the above description of the embodiments, according to the present invention, before cutting a regular workpiece,
By drilling a round hole in the workpiece while automatically moving the condensing lens up and down, and automatically focusing the condensing lens easily, quickly, and accurately, the operation up to cutting the regular workpiece is simplified. It can be done easily and in a short time.

[Brief explanation of the drawing]

Fig. 1 shows the main parts of the invention, and is a control block diagram of the automatic focus adjustment device, and Fig. 2 is a plan view of machining a round hole in the workpiece when automatically focusing the condenser lens. 3 are flowcharts for explaining the operation of the laser processing method of the present invention, and FIG. 4 is a perspective view of a laser processing machine according to an embodiment of the present invention. 1... Laser processing machine 13... Work clamp 1
7... Processing head 19... NC device 21...
Automatic focus adjustment device 23... CCD camera 27... Image processing device 33
...Condensing lens W...Work w,, w2, w
3...Round hole

Claims (1)

[Claims] When cutting a workpiece by irradiating the workpiece with a laser beam focused by a condenser lens installed in a laser processing machine, the workpiece is first drilled with a round hole several times while moving the condenser lens up and down. , each time measuring the area or diameter of the round hole with an automatic focus adjustment device installed in the laser processing machine,
0.0 mm downward from the position of the condenser lens at the smallest area or diameter of the measured round hole. X^m^
A laser processing method characterized in that the position moved by m is set as the optimum focal position of a condensing lens, and cutting is started on a regular workpiece.