JPS6372493A - Laser beam machine - Google Patents

Abstract

PURPOSE:To make accurate the laser beam machining by projecting laser light which is emitted from laser oscillator and condensed by a condenser lens on a work through an aperture movable vertically to control a spot diameter. CONSTITUTION:The laser light 2 emitted from the laser oscillator 1 is conducted to the condenser lens 4 via reflecting mirror 3 and projected on the work A6 through the aperture 5. The aperture 5 is moved in the vertical direction by a driving device 9 such as a stepping motor, etc., the control the spot diameter continuously. The accurate laser beam machining can be performed and the adaptation to the automation is made possible by a device with this constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a laser processing apparatus, and particularly to control of irradiation energy and spot diameter thereof.

(Prior Art) Conventionally, a laser processing device is configured as shown in FIG.
A laser beam 2 emitted from a laser oscillator 1 is guided to a condensing lens 4 side by a reflection mirror 3. Then, a part of the laser beam 2 becomes reflected light 14 due to an aperture 13 having a constant hole diameter installed in the optical path midway, and the aperture 1
The laser beam 15 that has passed through the hole 3 is condensed by the condenser lens 4, and is irradiated onto the workpiece 17 to perform machining.

Note that the hole diameter of the aperture 13 in this case is the same as that of the workpiece 17.
It is determined by the processing conditions, that is, the irradiation energy and spot diameter.

(Problems to be Solved by the Invention) In the conventional laser processing apparatus as described above, when performing laser processing on two workpieces with different processing conditions, apertures with different hole diameters are installed depending on the processing conditions. There is a need to. Furthermore, since it is difficult to continuously change the processing conditions, detailed laser processing is not possible.

The present invention provides a laser processing device that can cope with dense processing conditions by driving an aperture having a certain diameter up and down and continuously changing the irradiation energy or spot diameter, and is suitable for automation. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) This invention provides an aperture having a certain diameter between a condensing lens and a workpiece, and the aperture is connected to a driving device such as a stepping motor. This is a laser processing device that is simply driven in the vertical direction.

(Function) Generally, the beam diameter of the laser beam focused by the condenser lens gradually decreases in proportion to the distance from the condenser lens, and reaches its minimum at the focal position.

Therefore, in this invention, an aperture with a certain hole diameter provided between the condenser lens and the workpiece is driven in the vertical direction, so that the irradiation energy or spot diameter on the workpiece can be continuously controlled. becomes possible.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The laser processing apparatus of the present invention is configured as shown in FIGS. 1 and 2, and the same parts as in the conventional example (FIG. 3) are given the same reference numerals. A folding mirror 3 is disposed at a distance. A condenser lens 4, an aperture 5 having a constant diameter, and a workpiece 6 are arranged in sequence at predetermined intervals to face the folding mirror 3.

In this case, the aperture 5 is movable in the vertical direction by a driving device 9 such as a stepping motor, for example.
This is a feature of this invention. Further, the workpiece 〇 is placed on the automatic positioning device 8, but another workpiece B7 is placed on this automatic positioning device 8, and this workpiece vIJA6 and the workpiece B7 are placed on the automatic positioning device 8. It has processing conditions different from object B7. Then, drive the aperture 5 with the W
9 is driven up and down, and laser processing is performed on the workpiece 6 and the workpiece B7 in the same line.

Now, in the laser processing R[ of the present invention as described above, during operation, the laser beam 2 emitted from the laser oscillator 1 is guided to the condensing lens 4 side by the folding mirror 3, and is condensed by the condensing lens 4. , is irradiated through the aperture 5 to the workpiece 6. At this time, as shown in FIG. 2, the laser beam diameter in the condenser lens 4 is D1, the focal length of the condenser lens 4 is f, the hole diameter of the aperture 5 is a, and the distance from the focal position of the condenser lens 4 to 7 vertices 5 is If the aperture 5 is placed at a position such that b = a/D-f, where b is the distance, all of the laser beam 10 focused by the condensing lens 4 will pass through the hole of the aperture 5. It passes through and is irradiated to the workpiece.

The irradiation energy density F1 at the focal position at this time is Fl −4P1 /πd2 [J/m21. Here, Pl is the irradiation energy [J], d is the spot diameter at the focal position, and the spread of the laser beam 2 θ [rad]
, and the focal length f [layer] of the condenser lens, and is expressed as d-fa [layer]. Also, when the defocusing member is fo [si], the spot diameter COO is expressed as do = o * fa / f [x], and the irradiation energy density F1' at that time is Fl' = 4.
Px /πda 2 -4P1/π[)2, i'2 /f, 2[J/+
It becomes s+21.

Next, the automatic positioning device 8 guides the workpiece ThB7 having different processing conditions from the workpiece 6 to the processing point. At the same time, the aperture 5 is driven toward the condenser lens 4 by the drive device 9. At this time, when the aperture 5 is driven to a position where b>a/D-f, a part of the laser beam 10 focused by the condenser lens 4 becomes reflected light by the aperture 5, and the rest is reflected by the aperture 5. The light passes through the hole and is irradiated onto the workpiece B7. The irradiation energy density P2 at the focal position at this time is P2-Pl (a-f/b-D)2 [J] if the energy distribution of the laser beam 2 is multimode and approximately cylindrical. Therefore, the irradiation energy density F2 is F2=4P2/π
d2 −4 (a −f/b −D)2Pr /πd2=
4 (a-f/b-D)2F! [J/shoe 21.

Also, when the defocus amount is fa [sw], the spot diameter is cja' = f lo -a/b
[s], and the irradiation energy density F2' is F2' = 4P2 / πdo''' = 4 P/π D 2 ・ f2 / f ro 2
=Ft' [J/s+2.

In the laser processing apparatus according to the above embodiment, when laser processing is performed at approximately the focal point of the condenser lens 4,
By continuously changing the distance mb from the focal point (processing point) to the aperture 5, the irradiation energy P2 at the processing point
The irradiation energy density F2 changes continuously in inverse proportion to the square of b, and the spot diameter dO does not change.

In addition, when performing defocused laser processing, if the distance is continuously changed, the irradiation energy P2 will change in inverse proportion to the square of b, and the spot diameters d and l will change in inverse proportion to b. , the irradiation energy density F2' remains unchanged.

[Effects of the Invention] According to the present invention, since the aperture 5 disposed between the condenser lens 4 and the workpiece A6 (workpiece 87) is configured to be movable in the vertical direction, continuous The irradiation energy or spot diameter can be controlled. As a result, it is possible to provide a laser processing device suitable for automation because it can handle precise processing conditions and can process two workpieces with different processing conditions on the same line.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a laser processing device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing an enlarged main part of FIG. 1, and FIG. 3 is a schematic configuration diagram showing a conventional laser processing device. FIG. 1... Laser oscillator, 4... Condensing lens, 5...
Aperture, 6.7... Workpiece. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (1)

[Claims] A laser processing device for processing a workpiece by focusing laser light emitted from a laser oscillator by a condensing lens and irradiating it to a workpiece through an aperture, characterized in that the aperture is movable up and down. Laser processing equipment.