JP2010274267A - Laser processing machine - Google Patents

Abstract

Provided is a laser processing machine that has a small processing burden on a control device side and is excellent in processing shape and processing position accuracy even when the temperature of an fθ lens changes due to heat generation of the device itself or environmental temperature change.
Prior to processing, the temperature of an fθ lens is measured. In the NC control device, a work distance correction amount and a machining focal length correction amount are calculated from the temperature of the fθ lens 9. The work distance is adjusted so as to cancel the shift of the processing position due to the change in the optical characteristic of the fθ lens 9, and the interval of the collimator lens 15 is adjusted so that the processing focus is on the printed circuit board surface.
[Selection] Figure 1

Description

  The present invention relates to a laser processing machine, and more particularly to a laser processing machine that performs drilling, cutting, or marking on a material such as a resin material or a ceramic material in a printed circuit board or a semiconductor chip.

  FIG. 4 is a configuration diagram of a conventional printed circuit board laser drilling machine, which is one of laser processing machines.

  Galvano mirrors 7 and 8 and an fθ lens 9 are arranged on the optical axis 2 of the pulsed laser emitted from the laser oscillator 1. The printed circuit board 12 is placed on the processing table 11 so as to face the fθ lens 9.

  The galvanometer mirrors 7 and 8 and the fθ lens 9 are positioned by the Z-axis slider 17 in the vertical direction so that the processing focus is on the surface of the printed circuit board 12. The NC control device controls the laser oscillator 1, the galvanometer mirrors 7 and 8, the machining table 11 and the Z-axis slider 17.

  The operation of the conventional printed circuit board laser drilling machine configured as described above will be described.

  The pulsed laser emitted from the laser oscillator 1 is positioned in the X and Y directions by the galvanometer mirrors 7 and 8 positioned at a predetermined swing angle according to the processing program, and enters the fθ lens 9, and is incident on the printed circuit board 12. As a vertical laser, it is emitted from the fθ lens 9 and irradiated to the printed circuit board 12 to process the hole.

  When the processing of the hole in the processing area (for example, 50 mm × 50 mm) determined by the galvanometer mirrors 7 and 8 and the fθ lens 9 is completed, the processing table 11 is operated to position the next processing area with respect to the fθ lens 9. To do. Thereafter, the above operation is repeated until the processing is completed.

The fθ lens is obtained by mounting a plurality of spherical lenses or aspherical lenses on a lens barrel. In the case of a CO2 laser processing machine, a lens material mainly composed of zinc selenium or germanium is used. Germanium has a higher refractive index than zinc selenium and is suitable as a material for high-performance lenses. These materials are known to be temperature dependent with respect to the refractive index that determines the optical properties. In addition, since the lens barrel for mounting the lens expands and contracts depending on the temperature, the lens interval also changes.

  For this reason, when the temperature of the optical system including the fθ lens changes due to the heat generation of the apparatus itself or the environmental temperature change, there is a problem that the optimum work distance for processing is shifted. In addition, there is a problem that not only the optimum work distance shift but also the machining position shifts.

  As shown in FIG. 5, the processing position shifts in a direction in which the actual processing position contracts with respect to the target processing position with respect to the center of the processing area (scan area) determined by the galvanometer mirror and the fθ lens. appear.

  As a conventional technology to enable highly accurate adjustment of the laser beam irradiation position without being affected by changes in the surrounding environmental temperature, the light receiving sensor detects the laser beam irradiation position and outputs the light receiving sensor. Based on the above, it is determined whether or not the irradiation position of the laser beam reflected by the galvano mirror matches a predetermined irradiation position determined in advance, a necessary correction amount is calculated, and based on the calculated correction amount A technique for adjusting the irradiation position of a laser beam by driving a galvanometer mirror is disclosed (for example, see Patent Document 1).

JP 2000-098271 A

  However, in practice, there are individual differences due to assembly errors and the like, and there is a problem that it takes enormous man-hours to measure individual differences and set correction parameters.

  In actual control, the positioning cycle of the galvano mirror is about several hundreds μs to several ms, and positioning equal to or more than the number of processed holes is required. In order to improve the accuracy of the correction amount, it is not sufficient to adjust the initial processing. To correct the angle of the galvanometer mirror for each hole while always calculating the correction amount, there is a burden of correction calculation processing on the controller side. There is a problem that the productivity is increased and the productivity is reduced by the correction calculation processing time.

  In order to solve the above-described problems, a laser processing machine of the present invention is scanned by a laser oscillator that emits a laser beam, a galvano mirror that scans the laser beam by being driven and rotated, and a galvano mirror. An fθ lens optically designed so that the laser beam is focused on the same plane, a processing table on which a workpiece is placed and moved on the XY plane, and light of the laser beam emitted from the laser oscillator A group of collimating lenses provided on an axis, a driving device for adjusting the distance between the collimating lenses, and a Z-axis slider for adjusting a work distance between the fθ lens and a workpiece placed on the processing table And a temperature sensor for measuring a representative temperature of the optical system, and corresponding to the measurement value by the temperature sensor, the collimator The lens interval and the work distance are adjusted.

  Preferably, a representative temperature of the optical system is measured by installing a temperature sensor in the lens barrel of the fθ lens. Further, the collimator lens interval to be adjusted in accordance with the measurement value by the temperature sensor and the adjustment amount of the work distance are stored in the control device in advance.

  The correction calculation processing burden on the control device side is small, and correction can be performed without affecting productivity.

Configuration diagram according to an embodiment of the present invention Explanatory diagram showing the tilt angle of the fθ lens The flowchart explaining the operation of the present invention Configuration diagram of conventional laser processing machine Explanatory drawing showing position shift due to temperature change

  FIG. 1 is a diagram showing a configuration according to an embodiment of the present invention. The same components as those introduced in the background art are denoted by the same reference numerals, and the description thereof is simplified.

  On the optical axis 2 of the pulsed laser emitted from the laser oscillator 1, a collimating lens 15, galvanometer mirrors 7, 8 and an fθ lens 9 are arranged. The collimating lens 15 is composed of two single lenses 4a and 4b, and one lens 4b is attached to a driving device 16 for positioning in the optical axis direction.

  By adjusting the distance between the collimator lenses by the driving device 16, the divergence angle of the laser is adjusted, and the optimum work distance for processing can be adjusted. Thereby, even when the work distance is changed, it is possible to prevent processing defects due to defocusing.

  A temperature sensor 14 for measuring temperature is attached to the lens barrel of the fθ lens 9, and a temperature change of the lens barrel of the fθ lens 9 can be detected.

  The printed circuit board 12 is placed on the processing table 11 so as to face the fθ lens 9. The galvanometer mirrors 7 and 8 and the fθ lens 9 are positioned in the vertical direction by the Z-axis slider 17 so that the work distance can be adjusted.

  Next, the fθ lens will be described with reference to FIG.

  The laser beam positioned in the X and Y directions by the galvanometer mirror becomes a laser perpendicular to the printed circuit board and is emitted from the fθ lens and applied to the printed circuit board. Has a falling angle.

  Although it is perpendicular to the workpiece in the center of the scan area, the tilt angle becomes larger as it is at the outer periphery. For this reason, when the work distance is changed, the processing position is shifted in the direction in which the scan area expands and contracts.

  On the other hand, as described above, the positional deviation when the optical characteristic including the fθ lens changes due to the temperature change is the expansion / contraction direction of the scan area. By adjusting the work distance, it is possible to cancel the displacement of the scan area in the expansion / contraction direction.

  Next, the operation will be described. FIG. 3 is a flowchart for explaining the operation of the present invention.

  Prior to processing, the temperature of the lens barrel of the fθ lens 9 is measured by the temperature sensor 14 attached to the fθ lens 9.

  In the NC control device, the work distance correction amount and the processing focal length correction amount are calculated from the temperature of the lens barrel of the fθ lens 9.

  The Z-axis slider 17 adjusts the work distance so as to cancel the shift of the processing position due to the change in the optical characteristics of the optical system including the fθ lens 9.

  By changing the work distance, the displacement of the scan area in the expansion / contraction direction can be canceled.

  One lens of the collimator lens 15 is positioned in the optical axis direction by a driving device. The laser divergence angle is adjusted by adjusting the collimator lens interval.

  Thereby, even if the work distance is adjusted so as to cancel the processing position shift in the expansion / contraction direction of the scan area, the processing focus can be adjusted to the surface of the printed circuit board, so that it is possible to prevent processing defects due to focus position shift.

  Thereafter, similarly to the conventional processing machine, the pulsed laser emitted from the laser oscillator 1 is positioned in the X and Y directions by the galvanometer mirrors 7 and 8 positioned at a predetermined swing angle in accordance with the processing program, and the fθ lens. 9 enters the laser, becomes a laser perpendicular to the printed circuit board 12, exits from the fθ lens 9, is irradiated on the printed circuit board 12, and processes a hole.

  When the processing of the hole in the processing area (for example, 50 mm × 50 mm) determined by the galvanometer mirrors 7 and 8 and the fθ lens 9 is completed, the processing table 11 is operated to position the next processing area with respect to the fθ lens 9. To do. Thereafter, the above operation is repeated until the processing is completed.

  When the actual operation was performed in the environment where the apparatus was installed, the temperature change of the fθ lens 9 was about 0.1 degree per 10 minutes at most. The temperature resolution necessary for correction was about 0.1 degree. Accordingly, the correction may be performed in a cycle of about 5 minutes, and the processing load on the control device side can be reduced, and correction can be performed without affecting the productivity.

  The laser processing machine according to the present invention requires a small correction calculation processing burden on the control device side, and enables correction without affecting productivity, such as resin materials in printed boards, semiconductor chips, and the like. It is useful in laser processing machines that drill, cut, or mark materials such as ceramic materials.

1 Laser oscillator 2 Laser light 3 Mirror 4 Lens 7 Galvano mirror (X axis)
8 Galvano mirror (Y axis)
9 fΘ lens 11 processing table 12 printed circuit board 14 temperature sensor 15 collimating lens 16 driving device 17 Z-axis slider

Claims (3)

Optically designed so that the laser oscillator that emits the laser beam, the galvano mirror that scans the laser beam by being attached to a motor and driven to rotate, and the laser beam that is scanned by the galvano mirror are focused on the same plane A laser processing machine including a fθ lens and a processing table on which a workpiece is placed and moved on an XY plane,
Furthermore, a group of collimating lenses provided on the optical axis of the laser beam emitted from the laser oscillator, a driving device for adjusting the collimator lens interval, the fθ lens, and the processing table are mounted. Equipped with a Z-axis slider that adjusts the work distance with the workpiece, and a temperature sensor that measures the representative temperature of the optical system,
A laser processing machine, wherein the collimator lens interval and the work distance are adjusted in accordance with a measured value by the temperature sensor. The laser processing machine according to claim 1, wherein a representative temperature of the optical system is measured by installing a temperature sensor in a lens barrel of an fθ lens. 2. The laser beam machine according to claim 1, wherein a collimator lens interval and a work distance adjustment amount to be adjusted in accordance with a measurement value by a temperature sensor are stored in a control device in advance.

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