JPH0683909B2 - Laser processing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laser processing apparatus with good processing accuracy.

[Prior Art] Generally, in a laser processing machine, a laser beam oscillated by a laser oscillator is focused by a focusing lens, and the focused laser beam is applied to the workpiece to perform heat treatment on the workpiece. It can be applied or heat cut on the work piece.

Further, an NC (numerical control) device is attached to the laser processing machine, and by numerically controlling the workpiece or the laser optical axis, the workpiece and the laser optical axis are relatively moved, The workpiece can be machined into a predetermined plane shape.

The laser beam focused by the condenser lens has a focal point on the optical axis, but this optical axis is pre-adjusted to match the machining axis that can be recognized by the NC device. The numerical control is performed assuming that the optical axis is above.

However, the optical axis is adjusted to match the processing axis in the initial stage due to the ambient temperature, or due to the self-divergent heat of the laser processing machine, or due to other mechanical strain, etc., with the passage of time, Alternatively, it may deviate from the machining axis as it is used.

When the optical axis deviates from the machining axis, the NC device performs numerical control with the machining axis as a reference, so that the machining accuracy decreases according to the amount of deviation.

[Problems to be Solved by the Invention] Therefore, conventionally, in order to detect an optical axis shift, when the laser is a visible light laser such as a ruby laser or a YAG laser, the laser beam appearing on the workpiece is The spot was observed, and the lens system was adjusted so that the center of the spot coincided with the processing axis.

However, detection of optical axis deviation by spot observation is
This is impossible with an invisible laser such as a gas laser, and there is a problem in detection accuracy (adjustment accuracy). By the way, the NC device
While it is possible to control the relative movement between the workpiece and the processing axis with an error of 0.01 mm or less, it is difficult to set the adjustment error to 0.1 mm or less in the above spot observation.

Further, as described above, the optical axis shift occurs over time and with use, but the optical axis adjustment by the above-mentioned spot observation requires time and labor. It is difficult to deal with gaps in a timely and appropriate manner.

In view of the above points, the present invention easily, quickly, and accurately detects the deviation amount of the optical axis with respect to the machining axis, and numerically controls the relative movement between the machining axis and the workpiece based on the detected optical axis deviation amount. Do
It is an object of the present invention to provide a laser processing machine capable of improving processing accuracy by correcting an NC device.

[Means for Solving the Problems] In view of the conventional problems as described above, the present invention provides a laser oscillator, a condenser lens that condenses a laser beam from the laser oscillator on a predetermined processing axis, and The workpiece on the fixed table placed in the X, Y plane orthogonal to the machining axis is X, Y
An NC device that controls a clamp device that moves in a direction, an imaging device that is arranged at a predetermined position with respect to the origin of the fixed table that supports the workpiece, and the laser beam processed into the workpiece. The detection hole is positioned directly below the image pickup device, the center of the imaged hole is calculated, the shift amount between the center of the image pickup device and the hole center is calculated, and the shift in table coordinates is calculated based on this shift amount. An image processing device for calculating the amount, and a correction means for correcting the NC device to correct the displacement amount based on the displacement amount at the table coordinates by the image processing device are provided. A hole is provided directly below the imaging device, and an illumination device that illuminates the detection hole from below is provided directly below the hole of the table.

[Embodiment] A preferred embodiment of the present invention will be described below. First, the attached drawings will be briefly described. FIG. 1 is a perspective view of a laser processing machine according to an embodiment of the present invention, FIG. 2 is an explanatory view of a mounting position of an image pickup device, and FIGS. Illustration of optical axis,
FIG. 5 is a block diagram of the optical axis deviation amount detecting device, FIG. 6 is an explanatory view of a frame memory, FIG. 7 is an explanatory view of an optical axis deviation amount calculating method, and FIG. 8 is a flowchart of an origin correction process.

As shown in FIG. 1, the laser processing machine 1 includes a laser oscillator 5 located behind the machine body 3, an arm 7 projecting horizontally in front of the machine body 3, in front of the arm 7, and A processing head (not shown) provided below, an optical system (not shown in FIG. 1) for guiding a laser oscillated by the laser oscillator 5 to the head (detailed in FIG. 3), and the processing head And a fixed table 9 which is fixedly arranged below the table at a predetermined distance.

Further, the laser processing machine 1 is placed on the fixed table 9 and holds the workpiece W, and a clamp device CLP that conveys the position of the workpiece W to be processed directly below the processing head, and the clamp device CLP. NC device for numerically controlling table coordinates 1
1 and.

Further, in the laser processing machine 1 shown in the present example, an image pickup device 13 is provided on one side surface of the arm 7, and an illumination device 15 is provided below the table 9 immediately below the image pickup device 13, and the image pickup device 13 is provided. An image processing device 21 is provided between 13 and the NC device via a video signal line 17 and a control signal line 19.
The lighting device 15 includes the image processing device 21 and a power supply line 23 for lighting.
Connected by.

As shown in FIG. 3, the laser oscillator 5 is a laser beam.
Oscillates 25. Then, the oscillated laser beam is emitted from the arm 7.
The laser beam reflected by the mirror 27 provided inside is reflected toward the condenser lens 29 provided inside the processing head, and the reflected laser beam is condensed by the condenser lens 29 and focused on the upper surface of the workpiece. It has become.

The optical axis 31 of the laser beam is initially adjusted so as to coincide with the processing axis 33. In the state shown in FIG. 3, predetermined processing, for example, cutting processing, is performed at the processing point (focus) 35 of the laser beam.

FIG. 4 shows an enlarged view of the case where the optical axis 31 is displaced from the processing axis 33. In this way, when the optical axis shift occurs,
The machining point 35 is deviated from the intersection point (point to be machined) 33 'between the workpiece W and the machining axis 33 by δ. If this amount of deviation is left as it is, the processing accuracy will be deteriorated accordingly.

The NC device 11 causes the clamp device CLP to grip the workpiece W and controls the positioning of the workpiece W on the fixed table 9. This control is the same as the known one, and the X-axis and Y-axis servo motors Mx, not shown in FIG.
By applying a drive signal to My (see FIG. 5), the moving mechanism (not shown) of the clamp device CLP is driven to align the machining point of the workpiece W with the machining axis.

The imaging device 13 is composed of a CCD camera, an ITV camera, etc., converts imaging into a video signal, and outputs this to the video signal line 17.

The mounting position of the image pickup device 13 and the details of the image pickup method will be described with reference to FIG.

The mounting position of the imaging device 13 is a predetermined position (Xo, Yo) on the table coordinates on the side surface of the arm 7. The origin (reference point) of the workpiece is coincident with the origin O (0,0) of the table coordinates XY at the start of machining. Then, the image pickup device 13 picks up an image of the surface state of the workpiece placed at the attachment position (Xo, Yo), for example, the state where a hole is formed, at a predetermined magnification. For this reason, a hole of a predetermined size is formed directly below the image pickup device 13 of the table 9, and an illumination device 15 such as an incandescent lamp or a fluorescent lamp is provided immediately below the hole so that a high-contrast image can be captured. Is installed in an upright position.

As shown in FIG. 5, the image processing device 21 includes a binarization circuit 37.
And a frame memory 39, a CPU 41, a ROM 43, a RAM 45, and an input / output device 47.

The binarization circuit 37 digitizes a video signal which is an analog signal into 1,0 codes and stores the digital signal in the frame memory 39 as image data. As shown in FIG. 6, the frame memory 39 stores 1,0 signals in each pixel corresponding to the black and white portion of the image. The physical coordinates of the frame memory 39 are xy. The coordinates xy are coordinates (xo, y) at the mounting position (Xo, Yo) of the image pickup device of the table coordinates XY.
Corresponding to o), the relationship of the displacement amount is as follows: X = kx · x, Y = y · ky .... kx, ky are constants determined by the equivalent distance per pixel and the magnification of the image pickup device 13. In ROM43,
A program for arithmetic processing described later in FIG. 8 is stored. The input / output device 47 is connected to the bus 49 of the image processing device 21.
It is connected to the input / output device inside the NC unit 11,
It serves to transmit a start signal from the device 11 and a data signal to the NC device 11. Further, the input / output device 47 is the lighting device 15
The image processing device 21 can drive the relay R at the time of image pickup so that the lighting device 15 can be turned on.

In the laser processing machine having the above configuration, the origin correction processing of the NC device for coping with the optical axis shift will be described.

In FIG. 8, step 801 shows the determination of the start of the origin correction.

The execution of the origin correction process is started by an operator's command.For example, prior to the start of processing, every morning and afternoon, or when it is considered that the optical axis deviation occurs, a keyboard or the like is appropriately instructed. It is what will be started.

Step 803 is to NC the servomotors Mx, My shown in FIG.
Driven by device 11, move clamp device CLP, then
A process of making a hole of a size (Xo, Yo) in the field of view of the image pickup device (camera) 13 is shown in the workpiece W. This hole moves the work W to the position W'as shown in FIG.
o) It is carried out in such a manner that the point is brought directly below the machining axis 33.

After making a hole at the (Xo, Yo) point of the workpiece W, the clamp device CLP measures the center (Xo, Yo) of the processed hole by the imaging device (camera) 13
Bring it directly under (step 805).

Step 807 represents a process of outputting a drive signal from the NC device 11 to the image processing device 13 and causing the imaging device (camera) 13 to image the hole. Step 809 is 2 described in FIG.
The process of storing the image data in the frame memory 39 by using the image of the image pickup device 13 as a video signal by the operation of the digitization circuit 37 is shown.

Thus, the physical coordinates of the frame memory 39 shown in FIG.
The figure as shown in FIG. 7 is drawn in xy.
Reference numeral 51 indicates a figure of a hole formed at a point (Xo, Yo) of the workpiece W.

Therefore, the image processing device 21 first calculates the center (center of gravity) xG, yG of the hole 51 (step 811). And the second
At the center of the hole (xG, yG) and the center of the imaging device (camera) 13 (x
o, yo) deviation amount Δx, Δy is calculated (step 81)
3).

Δx = xG−xo, Δy = yG−yo ... And thirdly, the deviation amounts ΔX, Δy at the table coordinates XY are multiplied by the deviation amounts Δx, Δy by the coordinate conversion constants kx, ky shown in the equation. ΔY is calculated (step 815).

ΔX = kx · Δx, ΔY = ky · Δy ... Step 817 shows a process of outputting the data obtained by the formula to the NC device 11 via the input / output device 47 shown in FIG. The NC device 11 inputs this data, offsets the origin by ΔX and ΔY (step 819), and sets the machining axis 33 at the intersection (machining point) between the optical axis 31 and the workpiece W shown in FIG.
Is moved for numerical control, and the subsequent control is performed as if the optical axis shift did not occur. Since the data input to the NC device 11 is automatically performed through the control signal line 19, the processing result is displayed on the image processing device 21, the operator sees this display, and the displayed data is keyed in. Its processing is quick and easy compared to.

As described above, in the laser processing machine according to this embodiment, it is possible to automatically detect all optical axis deviations and automatically correct the optical axis deviations without adjusting the optical system. It becomes possible to always maintain good machining accuracy.

In the above embodiments, the hole for detecting the optical axis deviation amount is shown as an example of a perfect circle, but this hole does not necessarily have to be a perfect circle, and the reference position (xo, yo) of the frame memory is not necessarily required. On the other hand, anything that can detect the optical axis deviation may be used,
For example, a triangular shape, a quadrangular shape, a groove shape, or the like may be used.

[Effects of the Invention] As will be understood from the above description of the embodiments, in short, the present invention provides a laser oscillator (5) and a laser beam (25) from the laser oscillator (5) on a predetermined machining axis ( 3
3) A condenser lens (29) that condenses light onto the
Fixed table (9) placed in the X and Y planes orthogonal to 3)
An NC device (11) that controls a clamp device (CLP) that moves the upper workpiece (W) in the X and Y directions, and an origin (of the fixed table (9) that supports the workpiece (W) ( 0,
0) to the image pickup device (13) arranged at a predetermined position (x _O , y _O ), and the detection hole formed in the workpiece (W) by the laser beam (25). The center (X _G , Y _G ) of the hole (51) imaged by positioning just below 13) is calculated, and the center (x _O , y _O ) of the image pickup device (13) and the center of the hole (51) are calculated. An image processing device (21) that calculates the amount of deviation (ΔX, ΔY) from (X _G , Y _G ) and calculates the amount of deviation in table coordinates based on this amount of deviation (ΔX, ΔY), and this image The image pickup device of the table (9), comprising: a correction unit that corrects the NC device (11) to correct the displacement amount based on the displacement amount at the table coordinates by the processing device (21). This table (9) has a hole just below (13).
An illumination device (15) for irradiating the detection hole from below is provided directly below the hole.

As is apparent from the above configuration, in the present invention, the detection hole processed in the workpiece W by the laser beam 25 is positioned and imaged immediately below the imaging device 13, and the center of the detection hole (X _G , Y _G ) is calculated.

Then, in the present invention, the shift amount between the center (X _G , Y _G ) and the center (x _O , y _O ) of the imaging device 13 is calculated, and the shift amount in the table coordinates is calculated based on this shift amount. Since the correction is performed by calculation, there is no human intervention, the correction can be performed automatically and accurately, and the laser processing with high accuracy can be performed.

As described above, when the imaging device 13 images the detection hole of the workpiece W, the illumination device 15 irradiates the detection hole from below the hole provided in the table 9, so the imaging device 13 captures an image with high contrast. It is possible to detect the upper peripheral portion of the detection hole with high accuracy without being affected by the change in the plate thickness.

[Brief description of drawings]

FIG. 1 is a perspective view of a laser processing machine according to an embodiment of the present invention, FIG. 2 is an explanatory view of a mounting position of an image pickup device, FIGS. 3 and 4 are explanatory views of an optical axis, and FIG. FIG. 6 is a block diagram of an optical axis deviation amount detecting device, FIG. 6 is an explanatory diagram of a frame memory, and FIG.
FIG. 8 is an explanatory diagram of an optical axis deviation amount calculation method, and FIG. 8 is a flowchart of origin correction processing. 1 …… Laser processing machine 11 …… NC device 13 …… Imaging device 21 …… Image processing device 51 …… Hole image Δx, Δy …… Displacement amount on frame memory ΔX, ΔY …… Optical axis displacement amount ( Offset amount)

Claims (1)

[Claims] Claim: What is claimed is: 1. A laser oscillator (5) and a laser beam (25) from the laser oscillator (5) are provided with a predetermined machining axis (33).
Move the work piece (W) on the fixed table (9) arranged on the X and Y planes orthogonal to the processing axis (33) and the condenser lens (29) that collects light in the X and Y directions. Clamp device (CL
The NC device (11) for controlling P) and the fixed table (9) supporting the workpiece (W) are arranged at predetermined positions (x _O , y _O ) with respect to the origin (0, 0). The image pickup device (13),
The center (X _G , Y _G ) of the imaged hole (51) is calculated by positioning the detection hole processed in the workpiece (W) by the laser beam (25) just below the imaging device (13). In addition, the shift amount (ΔX, ΔY) between the center (x _O , y _O ) of the imaging device (13) and the center (X _G , Y _G ) of the hole (51) is calculated, and this shift amount (ΔX , ΔY), and an image processing device (21) for calculating a shift amount in table coordinates, and this image processing device (21)
The image pickup device (1) for the table (9), comprising: a correction unit for correcting the NC device (11) to correct the displacement amount based on the displacement amount at the table coordinates.
A laser processing machine, characterized in that a hole is provided directly under 3), and an illuminating device (15) for irradiating the detection hole from below is provided directly under the hole of the table (9).