JP2018176233A - Laser beam machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to perform machining of a workpiece having a complicated surface shape.SOLUTION: By two-dimensionally scanning with a laser beam 2 a machined surface 91 of a machined workpiece 90 for each lattice-like grid, processing to deep for each grid is performed. Depth of a removal part 94 formed on each grid is in accordance with a z coordinate value included in a z map data.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a laser processing method.

  Patent Document 1 discloses a technique for deflecting a laser beam emitted from a laser oscillator by a galvano deflection mechanism and scanning a workpiece with the laser beam in one or two dimensions. The portion irradiated with the laser beam is removed to form a removed portion (engraved) having a depth corresponding to the intensity of the laser beam. The bottom surface of the removal portion is the surface of the workpiece.

JP, 2016-117081, A

  However, during scanning by the laser beam, control can not be performed to change the output of the laser oscillator, and the intensity of the laser beam is constant. Therefore, the depth of the recess having a shape according to the scanning trajectory of the laser beam also becomes constant, and the surface shape of the workpiece can not be formed into a complicated three-dimensional shape such as a stepped surface.

  Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to enable processing of a workpiece having a complicated surface shape.

  The main invention for achieving the above object is a laser processing method of digging for each square by scanning two-dimensionally with a laser beam for each square that divides the work surface of the workpiece. .

  Other features of the present invention will become apparent from the description of the specification and the drawings described below.

  According to the present invention, workpieces of different depths can be processed for each square, and the surface shape of the workpiece can be made into a complicated three-dimensional shape.

FIG. 1 is a perspective view of a laser processing apparatus and a block diagram of a control system of the laser processing apparatus. FIG. 2 is a perspective view of a workpiece model represented in three-dimensional space by z map data. FIG. 3 is a view showing a data configuration of z map data. FIG. 4 is a perspective view showing a state in which deep cutting is performed by scanning a grid-like mass in a work surface with a laser beam. FIG. 5 is a perspective view showing a state in which deep milling is carried out by scanning the next mass with a laser beam subsequently to the state of deep drilling shown in FIG. 4. FIG. 6 is a perspective view showing a state in which deep milling is performed by scanning the next mass with a laser beam subsequently to the state of deep drilling shown in FIG. 5.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are subject to various technically preferable limitations for practicing the present invention. Therefore, the scope of the present invention is not limited to the following embodiments and illustrated examples.

<1. Laser processing equipment>
FIG. 1 is a perspective view of a laser processing apparatus 10. In FIG. 1, an X axis, a Y axis, and a Z axis are illustrated as auxiliary lines representing the direction. The X axis, Y axis and Z axis are orthogonal to each other, the X axis direction and the Y axis direction are horizontal directions, and the Z axis direction is a vertical direction. However, the Z axis may not be vertical as long as the X axis, the Y axis and the Z axis are orthogonal to each other.

  The laser processing apparatus 10 includes a holder 20, an XY drive mechanism 30, a processing head 40, a laser oscillator 41, an optical system 42, galvano deflection mechanisms 43 and 44, an fθ lens 45, a control unit 50, and the like.

  The holder 20 is a chuck that holds the workpiece 90. The mode of holding the workpiece 90 by the holder 20 is not particularly limited. For example, the holder 20 is a clamper (vise) that holds the workpiece 90 or a vacuum chuck that adsorbs the workpiece 90 by negative pressure. The workpiece 90 may be fixed directly to the holder 20 or may be fixed to the holder 20 via the holder. In a state in which the workpiece 90 is fixed to the holder 20, the workpiece surface 91, which is the surface of the workpiece 90, is exposed and directed upward. The work surface 91 is a plane parallel to the X axis and the Y axis.

  An XY drive mechanism 30 is provided under the holder 20. The XY drive mechanism 30 displaces the holder 20 and the workpiece 90 along an XY plane parallel to the X axis and the Y axis. Here, the XY drive mechanism 30 has an X-axis direction drive mechanism 31 and a Y-axis direction drive mechanism 32 which are constituted by a motor, a linear motion transmission mechanism, and the like. The X-axis direction drive mechanism 31 moves the Y-axis direction drive mechanism 32, the holder 20, and the workpiece 90 in the X-axis direction. The Y-axis direction drive mechanism 32 moves the holder 20 and the workpiece 90 in the Y-axis direction.

  A processing head 40 is provided above the holder 20 and the workpiece 90. The processing head 40 is provided with a laser oscillator 41, an optical system 42, a first galvano deflection mechanism 43, a second galvano deflection mechanism 44, and an fθ lens 45.

The laser oscillator 41 emits a laser beam 2 by amplification of light.
The optical system 42 is configured of a transmission lens, a reflection mirror, and the like. The optical system 42 collimates the laser beam 2 emitted by the laser oscillator 41 and causes the first galvano deflection mechanism 43 to enter. The optical system 42 is provided with a focusing mechanism, and the diameter of the spot 3 of the laser beam 2 is adjusted by the focusing mechanism, and the position of the spot 3 in the Z-axis direction is adjusted.
The first galvano deflection mechanism 43 has a motor 43a and a galvano mirror 43b provided on the output shaft of the motor 43a. The galvano mirror 43 b reflects the laser beam 2 collimated by the optical system 42 toward the second galvano deflection mechanism 44. The motor 43a swings the galvano mirror 43b to deflect the laser beam 2 reflected by the galvano mirror 43b.
The second galvano deflection mechanism 44 has a motor 44a and a galvano mirror 44b provided on the output shaft of the motor 44a. The galvano mirror 44 b reflects the laser beam 2 reflected by the galvano mirror 43 b of the first galvano deflection mechanism 43 toward the fθ lens 45. As the motor 44a swings the galvano mirror 44b, the laser beam 2 reflected by the galvano mirror 44b is deflected.
The fθ lens 45 is disposed above the holder 20 and the workpiece 90. lens 45 transmits the laser beam 2 reflected by the galvano mirror 44 b of the second galvano deflection mechanism 44 toward the workpiece 90. The fθ lens 45 may not be provided.

  The spot 3 of the laser beam 2 is displaced in the X-axis direction on the XY plane by the deflection of the laser beam 2 by the first galvano deflection mechanism 43, and the deflection of the laser beam 2 by the second galvano deflection mechanism 44 The spot 3 is displaced in the Y axis direction on the XY plane. The optical action of the fθ lens 45 makes the diameter of the spot 3 of the laser beam 2 uniform regardless of the position, and also makes the displacement speed of the spot 3 uniform. Below, the central position of the scanning range by the spot 3 is called a scanning central point.

  The control unit 50 controls the X-axis direction drive mechanism 31, the Y-axis direction drive mechanism 32, the first galvano deflection mechanism 43, the second galvano deflection mechanism 44, and the laser oscillator 41 described above. The control unit 50 is provided in a housing of the processing apparatus 10. The control unit 50 includes a servo control circuit, a laser control circuit, a microcomputer, and the like. The control unit 50 is connected to the CAM system 55.

  The CAM system 55 is a computer system having an input device, a display device, a storage device, a computer and the like. The CAM system 55 executes processing of generating z-map data based on shape data (design data, CAD data) of a workpiece and processing conditions, and processing of outputting the z-map data to the control unit 25. As shown in FIG. 2, the z map data is xy information by giving information of z coordinate values (height or depth) to each square obtained by dividing the xy plane of the three dimensional space into a grid as shown in FIG. The surface of the workpiece model 80 is represented by a large number of facets 81 parallel to the plane. The original model represented by the shape data (design data, CAD data) is included in the workpiece model 80 represented by the z-map data generated based on the shape data, and the small surface of the workpiece model 80 81 is set outside the surface of the original model. That is, the z-coordinate value of the small surface 81 of the workpiece model 80 is set higher than the z-coordinate of the surface of the original model within the same xy range (range in the x-axis direction and y-axis direction) as the small surface 81 .

  As shown in FIG. 3, the z map data includes a range in the x axis direction of each square (minimum value and maximum value of x coordinate) and a range in the y axis direction of each square (minimum value and maximum y coordinate) It is a data string consisting of a value, xy coordinate values of the center point of each square, and z coordinates of each square. The range in the x-axis direction, the range in the y-axis direction, xy coordinate values, and z coordinate values are set for each square. The x-axis, y-axis and z-axis of the orthogonal coordinate system set in the three-dimensional space correspond to the x-axis, y-axis and z-axis of the real space, respectively.

Here, the length in the x-axis direction and the length in the y-axis direction of each square may be predetermined values, or may be values input by the user using an input device. If the length in the x-axis direction and the length in the y-axis direction of each square are shorter, it is possible to process a workpiece with a higher definition surface.
Further, the reference (z = 0) of the z coordinate value of each square may be based on the processing surface 91 of the workpiece 90, or may be based on the back surface of the processing surface 91.

<2. Operation of laser processing apparatus and laser processing method>
A laser processing method using the laser processing apparatus 10 will be described with reference to FIGS. 4 to 6. 4 to 6 are enlarged perspective views showing portions to be sequentially removed by the laser processing apparatus 10.

(1) Setting First, the user fixes the workpiece 90 to the holder 20 and turns the workpiece surface 91 of the workpiece 90 upward. Then, the user inputs a processing command by the input device of the CAM system 55. Then, the CAM system 55 generates z map data and stores it in the storage device. Further, the CAM system 55 outputs the z map data to the control unit 50.

(2) Positioning The control unit 50 controls the X-axis direction drive mechanism 31 and the Y-axis direction drive mechanism according to the xy coordinate value with reference to the xy coordinate value of the center point of any square contained in the z map data Do. Then, the X-axis direction drive mechanism 31 moves the workpiece 90 in the X-axis direction, and the Y-axis direction drive mechanism 32 moves the workpiece 90 in the Y-axis direction. Thereby, the workpiece 90 is positioned such that the center point of the squares in the processing surface 91 is located at the scanning center point. Here, a square in the processing surface 91 is a square or rectangular area obtained by dividing the processing surface 91 into a grid.

(3) Laser Scanning Next, the control unit 50 turns on the laser oscillator 41 and controls the galvano deflection mechanisms 43 and 44. Then, the laser beam 2 is deflected by the galvano deflection mechanisms 43 and 44, and the spot 3 of the laser beam 2 incident on the processing surface 91 of the workpiece 90 is two-dimensionally displaced along the XY plane. That is, as shown in FIG. 4, the squares in the processing surface 91 are two-dimensionally scanned by the spot 3 of the laser beam 2. The movement trajectory of the spot 3 of the laser beam 2 is, for example, any of the following (a) to (d), but is not limited thereto.

(A) A locus of progressive scanning or interlaced scanning along a plurality of lines parallel to the X axis direction and shifted in the Y axis direction (b) parallel to the Y axis direction and the X axis Progressive scan or interlaced scan trajectories (c) along a plurality of misaligned lines (c) Trajectories combining the trajectories of (a) and (b) above (d) Spiral trajectories

  When the mass is deeply processed by two-dimensional scanning with the laser beam 2, a removal portion 94 is formed on the mass. The removal unit 94 refers to a quadrangular prism-like engraving (concave portion) defined by the range in the x-axis direction and the y-axis direction included in the z map data. The bottom surface 95 of the removing portion 94 is a square or rectangular flat surface parallel to the X-axis direction and the Y-axis direction.

  Here, during scanning of a square by the laser beam 2, the control unit 50 controls the output of the laser oscillator 41 and the speeds of the galvano deflection mechanisms 43 and 44 at a constant based on the z-coordinate value included in the z map data. The number of two-dimensionally scanning the grid is controlled based on the z-coordinate value. Then, the removing portion 94 is formed to the depth corresponding to the z coordinate value, and the bottom surface 95 of the removing portion 94 is formed at the position at the depth corresponding to the z coordinate value. The bottom surface 95 corresponds to the facet 81 of the workpiece model 80 represented by the z-map data.

(4) Sequential formation of a plurality of removal units Thereafter, the control unit 50 repeatedly executes the above-described processing of “(2) positioning” and “(3) laser scanning”. By doing this, as shown in FIG. 5 and FIG. 6, the other squares are also scanned by the laser beam 2 for each square, and the other removing portions 94 are sequentially formed for every square. Although the removal portions 94 are spatially connected, a recess 92 (see FIG. 1), which is an aggregate of the removal portions 94, is formed on the processing surface 91 of the workpiece 90. The bottom surface 95 of the removal portions 94 The curved concave surface is approximated by. The shape processed by laser processing is not limited to the recess 92.

  Since the above laser processing is rough processing, the processing time is short. And although finish processing is performed after laser processing, the total processing time of laser processing and finish processing can also be shortened by the part for time reduction of laser processing. The finish processing is laser processing, cutting processing or grinding processing.

<3. Effect>
According to the above embodiment, the following effects can be obtained.

(1) Since two-dimensional scanning is performed by the laser beam 2 for each square, even if the intensity of the laser beam 2 is constant during scanning of each square, if the depth of the removing portion 94 is different for each square You can Therefore, the surface shape of the aggregate of the bottom surface 95 of the removal portion 94 can be made into a complicated three-dimensional shape.

(2) The z-coordinate value is controlled by controlling the number of two-dimensionally scanning the grid based on the z-coordinate value while controlling the output of the laser oscillator 41 and the speed of the galvano deflection mechanisms 43 and 44 constant. The removal portion 94 can be formed to a depth corresponding to. Therefore, there is almost no processing error in the depth of each removing portion 94.

<4. About modification>
As mentioned above, although the form for implementing this invention was demonstrated, the above-mentioned embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. Further, the present invention can be changed and improved without departing from the gist thereof, and the present invention also includes the equivalents thereof. Below, the change from the above embodiment is demonstrated. The modifications described below may be applied in combination as much as possible.

(1) Although the X-axis direction drive mechanism 31 moves the holder 20 and the workpiece 90 in the X-axis direction, the movement of the holder 20 and the workpiece 90 in the Y-axis direction may be restricted. In this case, the processing head 40 is driven in the Y axis direction by the Y axis direction drive mechanism.

(2) Movements of the holder 20 and the workpiece 90 in the X-axis direction and the Y-axis direction may be constrained. In this case, the processing head 40 is driven in the X axis direction by the X axis direction drive mechanism and is driven in the Y axis direction by the Y axis direction drive mechanism.

(3) The holder 20 and the workpiece 90 may be driven in the Z-axis direction by the Z-axis drive mechanism, or the processing head 40 (all or part of the optical device from the laser oscillator 41 to the fθ lens 45) may be Z The axis drive mechanism may drive in the Z-axis direction. Then, the relative position of the spot 3 of the laser beam 2 with respect to the workpiece 90 in the Z-axis direction is adjusted by the Z-axis drive mechanism during the above-described positioning process. In this case, the position of the spot 3 in the Z-axis direction is finely adjusted by the focusing mechanism of the optical system 42 in the above-described laser process.

(4) In the above embodiment, the laser beam 2 is two-dimensionally deflected by the Galvano deflection mechanisms 43 and 44 which are mechanical light deflectors, but other light deflectors (acousto-optic deflectors, electro-optic deflections The laser beam 2 may be deflected by the

  DESCRIPTION OF SYMBOLS 2 ... Laser beam, 10 ... Laser processing apparatus 3 ... Spot, 90 ... Workpiece, 91 ... Work surface

Claims (2)

The laser processing method of digging processing for each said grid by scanning two-dimensionally with a laser beam for every grid which divided the to-be-processed surface of a to-be-processed object. The laser beam scans a square two-dimensionally to the depth corresponding to the z-coordinate value set for each square obtained by dividing the xy plane of the three-dimensional space into a grid shape. The laser processing method as described in.

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