JP4202305B2 - 3D laser processing machine - Google Patents

Description

  The present invention relates to a three-dimensional laser processing machine used mainly for cutting a three-dimensional thin plate.

  The three-dimensional laser processing machine is widely used mainly for cutting a thin plate having a three-dimensional shape. In general, a three-dimensional laser processing machine positions the tip of a nozzle that irradiates a workpiece with laser light with respect to the workpiece (determines a relative position and a relative posture with respect to the workpiece). There are three basic axes (X axis, Y axis, Z axis) and two rotation axes (C axis and A axis), and these axes are controlled by a control device (CNC). As for the allocation of the driving object for each axis, for example, the table on which the workpiece is placed is driven on the X axis, the Y axis, and the Z axis, and the head on which the nozzle is attached is driven on the remaining C axis and A axis. There are a system and a system in which a table on which a workpiece is placed is driven by the X axis and the Y axis, and a head to which a nozzle is attached is driven by the Z axis, the C axis, and the A axis.

  As is well known, control at the time of machining is normally performed according to a machining program. The most common way to create this machining program is to set the nozzle tip point (tip point set on the nozzle, usually at several desired positions on the actual workpiece cutting line (the line you want to cut). Are set as the laser beam condensing position), and the respective axis values at that time are sequentially stored as processing point data, which is called “processing program creation by teaching”.

One problem that arises in such teaching is that it is not easy to accurately teach the attitude of the nozzle. In laser processing, the direction of the nozzle (the optical axis direction of the laser beam) affects the direction of the cut surface. In most cases, the direction of the workpiece cut surface is desired to be perpendicular to the workpiece surface.
Therefore, in teaching, it is necessary to make adjustments (vertical adjustment) so that the direction of the nozzle is perpendicular to the surface of the workpiece, and to teach each axis value in the posture after the vertical adjustment. The vertical adjustment in the nozzle direction had to be made visually. Therefore, teaching takes time, and accurate vertical adjustment of the nozzle is not easy even for a skilled operator.

  In addition, a technique for controlling the nozzle attitude under a condition (for example, a fixed condition) that gives a relative position of the nozzle tip point of the laser processing machine to the workpiece is well known, and is described in Patent Documents 1 and 2 below. . Further, “Means for detecting intensity of reflected light from a workpiece” referred to as one of measuring means used in the present invention is disclosed in Patent Document 3 below.

JP-A-1-224194 JP-A-4-37496 Japanese Patent No. 3222430

  One object of the present invention is to provide a three-dimensional laser processing machine having a function of automatically adjusting the relative posture of a nozzle to a workpiece surface in a vertical direction. Another object of the present invention is to facilitate easy and efficient teaching work in creating a machining program for laser machining by facilitating accurate vertical adjustment of a nozzle that emits laser light. is there.

  In the present invention, in order to position the tip of the nozzle that irradiates the workpiece with laser light with respect to the workpiece, three basic axes (X axis, Y axis, Z axis) and the Z axis direction are rotated. A first rotation axis (C axis) for rotating the nozzle and a second rotation axis (A axis) for rotating the nozzle about an axis perpendicular to the first rotation axis (C axis); Control means for controlling the basic three axes, the first rotation axis, and the second rotation axis, and the control means makes the relative position of the tip point set on the nozzle relative to the workpiece constant. The present invention is applied to a three-dimensional laser processing machine including posture changing means for changing the posture of the nozzle while maintaining it.

The feature of the three-dimensional laser beam machine according to claim 1 is that the measuring means for measuring the intensity transition of the reflected light from the workpiece when the posture change is given to the nozzle by the posture changing means, Based on the measurement result of the intensity transition by the measuring unit, the nozzle includes a posture determining unit that obtains a posture in which the nozzle is perpendicular to the surface of the workpiece, and the posture changing unit includes the first rotating shaft and From a predetermined inclination state in which an inclination amount of a predetermined angle is given to each of the second rotation shafts, the nozzle is rotated 360 around the Z-axis direction while keeping the relative position of the tip point of the nozzle with respect to the workpiece. The first tip changing means for rotating the nozzle and the tip of the nozzle under the condition that the first angle of the C-axis at which the measurement value obtained by the measuring means is maximum during the first posture change is maintained. Said coverage of points Second posture changing means for changing the A axis within a predetermined range while keeping the relative position to the object constant, the posture determining means based on the measurement result of the intensity transition by the measuring means. Means for obtaining a first angle of the A axis that maximizes a measurement value obtained by the measuring means during two attitude changes, and a first angle of the C axis and a first angle of the A axis. Whether the first nozzle posture to be determined is a posture in which the nozzle is perpendicular to the surface of the workpiece, a determination result of “positive” or “negative” in light of a predetermined acceptance criterion. And a determination means to be provided.

Here, wherein when the determination result by the determining means is "negative", it is also possible to means further provided for switching a predetermined inclination amount of the A-axis in the predetermined inclined state (claim 2).
Also, in the three-dimensional laser processing machine according to any one of claims 1 and 2 , the measuring means including a photodetector provided at a tip portion of the nozzle can be used. .

  According to the three-dimensional laser beam machine according to the present invention, accurate vertical adjustment of the nozzle for irradiating laser light is automated and can be easily performed. Therefore, the teaching work in creating a machining program for laser machining is made more efficient, and accurate teaching can be performed without requiring a high degree of skill.

  FIG. 1 is a diagram showing a schematic configuration of a laser beam machine according to an embodiment of the present invention, and the C-axis and A-axis drive mechanisms are depicted in some detail. In the figure, reference numeral 1 denotes a C-axis drive servomotor, and reference numeral 2 denotes an A-axis drive servomotor. The C-axis is a rotating shaft (first rotating shaft) that rotates the nozzle 9a around the Z-axis direction, and the rotation of the servo motor 1 for driving the C-axis rotates the support member 5 by the gears 4a and 4b. Yes. On the other hand, the A-axis is a rotating shaft (second rotating shaft) that rotates the nozzle 9a around an axis perpendicular to the C-axis, and the rotation of the A-axis driving servo motor 2 causes the shaft 7 to be rotated by the gears 6a and 6b. The rotation is transmitted to the shaft 9 by the bevel gears 8a and 8b.

  Although details of the bearing mechanism and the like are not shown, the shaft 9 is supported on the support member 5 so as to be rotatable around an axis perpendicular to the C axis. The nozzle 9a is attached to the shaft 9 and fixed. With the above mechanism, when the C-axis drive servomotor 1 operates, the nozzle 9a rotates around the Z-axis direction, and when the A-axis drive servomotor 2 operates, the nozzle 9a rotates around the axis perpendicular to the C-axis. Rotates. Needless to say, if both rotate at the same time, these rotations occur simultaneously.

  The laser beam is supplied from a laser oscillator (not shown), and is irradiated toward the workpiece (workpiece) W from the tip of the nozzle 9a through a transmission path using a reflection mirror, an optical fiber, or the like. . Reference numeral 30 denotes an annular photodetector mounted in a manner fitted to the tip of the nozzle 9a, and detects the intensity of the reflected light of the laser beam applied to the workpiece W, as will be described later. The opening of the photodetector 30 is circular and is aligned with the optical axis of the laser beam.

  The workpiece W is positioned on the workpiece table 20. Here, the work table 20 is driven by three basic axes (X axis, Y axis, Z axis). However, the work table 20 is, for example, an XY table, and the above-described C axis and A axis drive mechanisms and nozzles are used. The entire portion including 9a may be driven by the Z axis. Details of the X-axis, Y-axis, and Z-axis drive mechanisms are omitted.

Control of each axis is performed by a control device indicated by reference numeral 10. The control device 10 is constituted by a CPU, a memory, an interface with an external device, and the like, and is well known except for software for capturing the output of the photodetector 30 and processing described later. For example, a manual operation unit 11 such as a keyboard and a display 12 such as an LCD are attached to the control device 10, and an operator inputs and corrects various commands, parameters, and the like necessary for the operation of the laser processing machine, processing program creation, and editing. Etc. can be performed.
Here, the “nozzle tip point fixing control” will be briefly described. As is well known, a condensing lens is provided in the nozzle 9a, and the condensing position of the laser beam is at a position away from the tip of the nozzle 9a by a short distance forward. Usually, the point P corresponding to this condensing position is set as the “nozzle tip point”. Therefore, in teaching for creating a machining program, it is only necessary to match the nozzle tip point P with a desired machining point and store the axis values at that time. However, for the reason described above, vertical adjustment of the nozzle attitude (adjustment for directing the nozzle perpendicular to the surface of the workpiece) is necessary during teaching.

  It has been conventionally known that this vertical adjustment is performed by manually adjusting the nozzle posture while the position (posture is not included) of the nozzle tip point P is fixed. This is called “nozzle tip fixing control”. If “nozzle tip point fixing control” is used, an arbitrary value or a change in the value can be taken independently of the C axis and the A axis while the position (posture is not included) of the nozzle tip point P is fixed. it can. Since such nozzle tip point fixing control itself belongs to a well-known technique, a detailed description of the control method itself is omitted.

  Next, the relationship between the reflected light intensity detected by the annular photodetector 30 and the nozzle attitude will be described with reference to FIG. FIG. 2A shows a state where the nozzle is vertically adjusted and a state where the nozzle is inclined at an inclination angle θ. When the laser beam is irradiated toward the surface of the workpiece W, reflected light is generated on the workpiece surface, and a part of the reflected light enters the photodetector 30 and is detected. The reflected light is normally considered to be light in which specularly reflected light (reflected light assuming a mirror surface) is mixed with irregularly reflected light (light scattered in the range of the solid angle 2π from the incident point P). In this case, the reflected light intensity q detected by the photodetector 30 shows a monotonically decreasing relationship with an increase in the inclination angle of the nozzle (angle formed by the laser beam optical axis with respect to the surface of the workpiece W) θ. An example is shown in the graph of FIG. In the present embodiment, as will be described below, based on such a relationship, the photodetector 30 is used as an “tilt detector” when the nozzle is vertically adjusted.

When performing vertical adjustment of the nozzle for each teaching point, as a preparation, the reflection intensity value qmax when the nozzle is vertical is obtained by an appropriate means. Further, an allowable range (qmax to qmax−Δq) for determining “vertical adjustment completion” is determined and stored in the memory in the control device 10.
With the above preparation, vertical adjustment is performed according to the procedure described in the flowchart of FIG. Since the vertical adjustment at each teaching point is the same, the processing procedure for one teaching point will be described. Also, in the description, FIG. 4 showing the change or state of the nozzle posture is referred to as appropriate in relation to the flowchart. When the reflected light is obtained, laser oscillation is performed, and its output is set to a minimum output, for example. The main points of each step are as follows.

Step S1: Initially set an index n related to the repetition limitation of the processing cycle to n = 1.
Step S2: The nozzle is set to an appropriate initial posture and the 5-axis value is stored. The initial posture is, for example, a posture that is extremely rough by an operator and visually adjusted vertically.
Step S3: It is checked whether or not the detection value of the photodetector 30 is within the allowable range stored in the above preparation. If it is within the allowable range, it is determined that the vertical adjustment is completed, and the process proceeds to step S12. Otherwise, the process proceeds to step S4.
Step S4: From the initial state, the nozzle is tilted to the designated angle and direction for the nth time by the tip point fixing control under the condition that the tip point P is fixed. Here, “designation of angle” can be performed, for example, by designating a C-axis value, and “designation of direction” can be performed, for example, by inputting an A-axis value. Here, a total of N sets of C-axis values and A-axis values are prepared, and the n-th set value is input by operating the keyboard 11 in the n-th designation. The “designated angle and direction” is preferably a posture different from the initial state, for example, as indicated by S4 in FIG. 4, and has a larger inclination angle than the initial state (displaced from the vertical). It does not matter if it corresponds to.

Step S5: From the state where the inclination of Step S4 is completed, the tip is fixed and the nozzle is rotated 360 degrees around the Z-axis direction by the tip fixing control (see S5 in FIG. 4). The intensity transition of the reflected light detected by the detector 30 (the relationship between the C-axis value and the reflected light intensity) is recorded.
Step S6: It is checked whether or not the maximum value of the detection value obtained in step S5 is within the allowable range stored in the above preparation. If it is within the allowable range, it is determined that the vertical adjustment is completed, and the process proceeds to step S12. Otherwise, the process proceeds to step S7.
Step S7: The inclination state where the maximum value is obtained in step S7 is set.
Step S8: From the state in which the inclination of Step S7 is completed, the tip A point value is changed in a predetermined angular range in both directions ± (in both directions of increase / decrease) by tip point fixing control with the tip point P fixed (in FIG. 4). In step S8, the intensity transition of the reflected light detected by the photodetector 30 (the relationship between the A-axis value and the reflected light intensity) is recorded. Here, the predetermined angle range may be, for example, the same angle (for example, 30 degrees) in both directions on the basis of the A-axis value at the time of completion of step S7.

  Step S9: It is checked whether or not the maximum detected value obtained in step S8 is within the allowable range stored in the preparation. If it is within the allowable range, it is determined that the vertical adjustment is completed, and the process proceeds to step S12. Otherwise, the process proceeds to step S10.

  Step S10: It is checked whether or not the index n has reached the limit number N. If not, the process proceeds to step S11. If the limit number has been reached, the vertical adjustment is determined to be unsuccessful and the process is terminated. In this case, this is dealt with by reviewing and repairing the set values such as the allowable range of reflected light intensity, the specified angle / direction (see step S4), and the like.

Step S11: The index n is incremented by 1, and the process returns to Step S4 to repeat the processes after Step S4.
Step S12: The 5-axis value corresponding to the state where the vertical adjustment is completed is stored. In addition, when progressing to step S12 from step S3, the 5-axis value of an initial state is employ | adopted as it is. When the process proceeds from step S6 or step S9 to step S12, the 5-axis value at the time when the maximum value of the reflection intensity is detected is adopted.

  Through the above processing, the vertical posture is automatically searched within a range not exceeding the limit number N. When the vertical adjustment is completed for one teaching point, the nozzle is moved to the next teaching point, the position is adjusted (the nozzle tip point P is made to coincide with the teaching point), and the above-described processing is executed again. In this way, according to the present embodiment, it is possible to execute teaching work that is significantly more efficient than the conventional method in which vertical adjustment is performed manually and visually.

As a special case, it is considered that the vertical adjustment of the nozzle may not correspond to the detection of the maximum reflected light due to the reflection characteristics of the workpiece surface. In such a case, the reflected light intensity transition corresponding to the posture change is examined by experiment in advance as in steps S5 and S8, and the feature point corresponding to the vertical adjustment may be replaced with “maximum value”. As this feature point, for example, “minimum value”, “intermediate point between the maximum value giving the maximum value and the maximum value giving the value next to the maximum value” can be considered.
Further, the detection means for detecting the reflected light is not limited to the photodetector 30 described above, and other means may be substituted. As an example of an alternative means, the laser detector output (disposed near the rear mirror of the laser oscillator) used in the above-mentioned Patent Document 3 causes the laser oscillation output generated when the reflected light returns into the resonator. It is conceivable to monitor the change of the above. The point is that the type of detection means is not limited as long as the inclination of the nozzle can be detected by reflected light.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed schematic structure of the laser beam machine which concerns on one Embodiment of this invention, About the drive mechanism of C axis | shaft and A axis | shaft, it is drawn in some detail. It is a figure explaining the relationship between the attitude | position of a nozzle and reflected light intensity, (a) shows the state in which the nozzle was adjusted vertically, and the state inclined by inclination-angle (theta), and (b) shows reflected light intensity and inclination-angle. This relationship is illustrated by a graph. It is the flowchart which described the outline of the process sequence performed by embodiment. It is the figure which described the change of the nozzle attitude | position in relation to the flowchart shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Servo motor for C-axis drive 2 Servo motor for A-axis drive 3 Laser beam 4a, 4b, 6a, 6b Gear 5 Support member 7, 9 Shaft 8a, 8b Bevel gear 10 Controller 11 Keyboard (manual operation part)
12 Display 20 Worktable 30 Photodetector

Claims (3)

In order to position the tip of the nozzle that irradiates the workpiece with laser light with respect to the workpiece, the nozzle is moved around the basic three axes (X axis, Y axis, Z axis) and the Z axis direction. A first rotation axis (C axis) to be rotated, a second rotation axis (A axis) for rotating the nozzle around an axis perpendicular to the first rotation axis (C axis), and the three basic axes And control means for controlling the first rotating shaft and the second rotating shaft,
In the three-dimensional laser processing machine, the control means includes posture changing means for changing the posture of the nozzle while maintaining a constant relative position of the tip point set to the nozzle to the workpiece.
Measuring means for measuring the intensity transition of the reflected light from the workpiece when the posture change is given to the nozzle by the posture change means;
Posture determining means for obtaining a posture in which the nozzle is perpendicular to the surface of the workpiece based on the measurement result of the intensity transition by the measuring means ;
The posture changing means is
The nozzle is moved while maintaining the relative position of the tip of the nozzle with respect to the workpiece from a predetermined tilt state in which a tilt amount of a predetermined angle is given to each of the first rotary shaft and the second rotary shaft. First posture changing means for rotating 360 degrees around the Z-axis direction;
The relative position of the tip of the nozzle with respect to the workpiece is constant under the condition that the first angle of the C-axis that maximizes the measurement value obtained by the measuring means during the first posture change is maintained. Second posture changing means for changing the A axis within a predetermined range while maintaining
The posture determining means includes
Means for obtaining a first angle of the A axis at which a measured value obtained by the measuring means becomes maximum during the second posture change based on the measurement result of the intensity transition by the measuring means;
Predetermined tolerance as to whether the first nozzle attitude determined by the first angle of the C axis and the first angle of the A axis is an attitude in which the nozzle is perpendicular to the surface of the workpiece. A three-dimensional laser processing machine , comprising: a determination unit that provides a determination result of either “positive” or “negative” in accordance with a reference . The three-dimensional laser beam machine according to claim 1, further comprising means for switching a predetermined inclination amount of the A axis in the predetermined inclination state when a determination result by the determination means is "No". The three-dimensional laser processing machine according to claim 1, wherein the measurement unit includes a photodetector provided at a tip portion of the nozzle.

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