Time difference setting device and numerical control device

Abstract

A time difference setting device capable of appropriately setting a timing of laser output change sets an instruction time difference which is a time difference of an output timing of a laser instruction with respect to a positioning instruction, the time difference setting device including: a speed variation acquisition section which acquires a speed variation of a drive mechanism with respect to a positioning instruction based on a machining program; a mechanism delay time calculation section which calculates a delay time of positioning of the drive mechanism with respect to the positioning instruction, that is, a mechanism delay time; a laser output calculation section which calculates a variation in output of a laser oscillator with respect to a laser instruction based on the machining program using an oscillator model which simulates an operation of the laser oscillator; a laser delay time calculation section which calculates a delay time of the output of the laser oscillator with respect to the laser instruction, that is, a laser delay time; and an instruction time difference setting section which sets the instruction time difference based on the mechanism delay time and the laser delay time with respect to an interval in which emission of the laser is specified in the machining program.

Description

TECHNICAL FIELD

[0001] The present application relates to a time difference setting device and a numerical control device. BACKGROUND

[0002] In a laser processing machine, reduction in processing accuracy caused by delay before a command value output from a control device and specifying a position of a drive shaft, an output of a laser, and the like is reflected to an actual output and the like is studied. As a specific example, a technique is proposed in which when a remaining time of movement in a program block in execution of a processing program reaches a switching time decided in accordance with a delay time of a drive shaft, a laser oscillator, and the like, a laser command of the program block in effect is switched to a laser command of a next program block (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2016-155169 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The delay of a drive shaft and a laser oscillator is not always fixed and can vary in accordance with a kind of processing and the like. Therefore, in order to further improve the processing accuracy, it is desired to adjust the switching time of the laser in accordance with a processing program. However, it is extremely cumbersome to correct a set value of the switching time assuming a time constant for each processing program. Therefore, a technique capable of appropriately setting a timing of laser output change is desired.

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] The time difference setting device of one embodiment of the present disclosure sets a time difference, i.e., a command time difference, in a laser processing system including a laser oscillator that generates laser light, a laser head that emits the laser light, a drive mechanism that positions a relative position of the laser head and a workpiece, and a numerical control device that generates a laser command for the laser oscillator and a positioning command for the drive mechanism according to a processing program, the time difference being an output timing of the laser command with respect to the positioning command. The time difference setting device includes a speed change acquisition unit that acquires a speed change of the drive mechanism with respect to the positioning command based on the processing program; a mechanism delay time calculation unit that calculates a mechanism delay time, which is a delay time of positioning of the drive mechanism with respect to the positioning command, based on the speed change of the drive mechanism acquired by the speed change acquisition unit; a laser output calculation unit that calculates an output change of the laser oscillator with respect to the laser command based on the processing program using an oscillator model that simulates an operation of the laser oscillator; a laser delay time calculation unit that calculates a laser delay time, which is a delay time of an output of the laser oscillator with respect to the laser command, according to the output change of the laser oscillator calculated by the laser output calculation unit; and a command time difference setting unit that sets the command time difference with respect to an interval in which emission of the laser light is specified in the processing program, based on the mechanism delay time calculated by the mechanism delay time calculation unit and the laser delay time calculated by the laser delay time calculation unit.

[0010] Another numerical control device according to the present disclosure, in a laser processing system including a laser oscillator that generates laser light, a laser head that emits the laser light, and a drive mechanism that positions a relative position of the laser head and a workpiece, generates a laser command for the laser oscillator and a positioning command for the drive mechanism according to a processing program, wherein the numerical control device includes: a speed change acquisition unit that acquires a speed change of the drive mechanism with respect to the positioning command based on the processing program; a mechanism delay time calculation unit that calculates a mechanism delay time based on the speed change of the drive mechanism acquired by the speed change acquisition unit, the mechanism delay time being a delay time of positioning of the drive mechanism with respect to the positioning command; a laser output calculation unit that calculates an output change of the laser oscillator with respect to the laser command based on the processing program using an oscillator model that simulates an operation of the laser oscillator; a laser delay time calculation unit that calculates a laser delay time, which is a delay time of output of the laser oscillator with respect to the laser command, according to the output change of the laser oscillator calculated by the laser output calculation unit; and a command time difference setting unit that sets, for an interval in which emission of the laser light is specified in the processing program, a command time difference, which is a time difference of output timing of the laser command with respect to the positioning command, based on the mechanism delay time calculated by the mechanism delay time calculation unit and the laser delay time calculated by the laser delay time calculation unit.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to provide a time difference setting device and a numerical control device that can appropriately set a timing of switching laser output. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a block diagram showing a structure of a laser processing system including a numerical control device according to one embodiment of the present disclosure.

[0014] Figure 2 is a block diagram showing a structure of a laser processing system including a time difference setting device according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0015] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Figure 1 is a block diagram showing a structure of a laser processing system 1 including a numerical control device 100 according to one embodiment of the present disclosure.

[0016] The laser processing system 1 of this embodiment includes a laser oscillator 10 that generates laser light, a laser head 20 that emits the laser light, a drive mechanism 30 that positions the relative positions of the laser head 20 and a workpiece W, and a numerical control device 100 that controls the laser oscillator 10 and the drive mechanism 30 based on a processing program. The laser processing system 1 is a system that performs processing by irradiating the workpiece W with laser light.

[0017] The laser oscillator 10 generates output laser light corresponding to a laser command input from the numerical control device 100. As the laser oscillator 10, for example, a YAG laser oscillator, a carbon dioxide laser oscillator, an excimer laser oscillator, or the like can be used.

[0018] The laser head 20 emits the laser light generated by the laser oscillator 10 in a manner to irradiate the workpiece W with the laser light. The laser head 20 has an optical system that focuses the laser light on the workpiece W.

[0019] The drive mechanism 30 moves at least one of the laser head 20 and the workpiece W in accordance with a positioning command input from the numerical control device 100. As the drive mechanism 30, for example, a positioning mechanism having a plurality of drive shafts such as a Cartesian coordinate type robot, a vertical multi-joint type robot, a SCARA type robot, a parallel link type robot, or the like can be used, and an actuator having only a single drive shaft can also be used. In addition, the drive mechanism 30 can be configured to detect the positions of the drive shafts and input a feedback signal to the numerical control device 100.

[0020] The numerical control device 100 generates a laser command for the laser oscillator 10 and a positioning command for the drive mechanism 30 in accordance with the processing program. In addition, the numerical control device 100 sets a command time difference, which is the time difference between the output timing of the laser command and the output timing of the positioning command, in consideration of the responsiveness of the laser oscillator 10 and the drive mechanism 30. The numerical control device 100 can be implemented, for example, by causing a computer device having a memory, a CPU, an input / output interface, and the like to execute an appropriate control program.

[0021] The numerical control device 100 has a main storage section 101, a program analysis section 102, an interpolation section 103, a laser command generation section 104, a laser command switching section 105, a laser output calculation section 106, a laser delay time calculation section 107, a positioning command generation section 108, a positioning command switching section 109, a speed change acquisition section 110, a mechanism delay time calculation section 111, and a command time difference setting section 112. In addition, these constituent elements are obtained by classifying the functions of the numerical control device 100, and can not be structures that can be clearly distinguished in the physical structure and the program structure.

[0022] The main storage section 101 stores a machining program and a set value of the command time difference. In addition, the main storage section 101 can also store parameters or codes for determining the specifications of the laser oscillator 10 and the drive mechanism 30, and set values for deciding the processing methods of other constituent elements of the numerical control device 100, and the like.

[0023] The machining program is described in a language such as G code, for example. Specifically, the machining program can include a plurality of command sentences for determining the specified coordinates through which the laser head 20 should pass, the moving speed, and the curvature of the moving path, the output of the laser oscillator 10, and the like.

[0024] The program analysis section 102 analyzes the machining program and converts it into a data form that can be processed in other constituent elements of the numerical control device 100.

[0025] The interpolation section 103 calculates various control target values at each time according to the machining program. As specific examples, the control target values calculated by the interpolation section 103 include the position or speed of each drive shaft of the drive mechanism 30, the output of the laser oscillator 10 at each time, and the like. The structure of this interpolation section 103 is the same as that in the numerical control device of a conventional laser processing system.

[0026] The interpolation section 103 can also perform acceleration / deceleration processing that applies a correction to the motion specified by the machining program so that the drive mechanism 30 is not required to exert a load exceeding the limit, that is, the acceleration of each drive shaft is suppressed to be below an upper limit value. With respect to such interpolation, it can also be set to be the same as in the past.

[0027] The laser command generation section 104 generates a signal that instructs the laser oscillator 10, that is, a laser command signal, based on the target values interpolated by the interpolation section 103. The method of generating the laser command signal is the same as that in the numerical control device of a conventional laser processing system. Normally, the value of the laser command changes in steps according to the machining program. In addition, the laser command generation section 104 is configured so that the reference time of its output is delayed with respect to the reference time of the output of the positioning command by the command time difference stored in the main storage section 101.

[0028] The laser command switching section 105 selects whether to input the laser command signal generated by the laser command generation section 104 to the laser oscillator 10 or to the laser output calculation section 106.

[0029] The laser output calculation section 106 calculates the change in the output of the laser oscillator with respect to the laser command based on the machining program using an oscillator model that simulates the motion of the laser oscillator 10. As an example, the oscillator model can be set so that the start of the change in the laser output is delayed with respect to the laser command signal, and the slopes of the rising and falling edges of the laser output are limited.

[0030] The laser delay time calculation section 107 calculates a delay time of the laser oscillator 10 with respect to the laser command, i.e., a laser delay time, based on the output variation of the laser oscillator 10 calculated by the laser output calculation section 106. The laser delay time is calculated as a time from an instant of a value step change of the laser command to a time when a value of the output calculated by the laser output calculation section 106 becomes a value substantially equal to a changed value of the laser command. Further, "substantially equal" can be judged as a state where a difference therebetween is equal to or less than a threshold value set in advance in consideration of a simulation including an error and a value calculated at only a fixed time interval.

[0031] In the machining program, the output of the laser can be changed multiple times. Therefore, the laser delay time calculation section 107 can calculate the laser delay time as an average value of the machining program as a whole or an average value in a work range divided according to contents thereof.

[0032] The positioning command generation section 108 generates a positioning command signal as a signal instructing the drive mechanism 30 based on the target value interpolated by the interpolation section 103. The positioning command signal can be generated multiple times in correspondence with multiple drive shafts of the drive mechanism 30, respectively. The method of generating the positioning command is the same as that in the numerical control device of the conventional laser processing system.

[0033] The positioning command switching section 109 selects whether to input the positioning command signal generated by the positioning command generation section 108 to the drive mechanism 30 or to the speed variation acquisition section 110. That is, the positioning command switching section 109 selects whether to perform a process of actually processing the workpiece W or to perform a process of setting a command time difference most suitable for the predetermined laser processing before the workpiece W is processed.

[0034] The speed variation acquisition section 110 acquires a speed variation of the drive mechanism 30 with respect to the positioning command based on the machining program. As a method of acquiring the speed variation of the drive mechanism 30, there are a method of calculating the speed variation of the drive mechanism 30 with respect to the positioning command using a mechanism model simulating an action of the drive mechanism 30, and a method of actually making the drive mechanism 30 act without irradiation of the laser and obtaining the speed variation from a feedback signal of the drive mechanism 30. The speed variation acquisition section 110 of the present embodiment is configured to be able to calculate the speed variation of the drive mechanism 30 by simulation using the mechanism model and to be able to confirm the speed variation of the drive mechanism 30 from the feedback signal of the drive mechanism 30.

[0035] The mechanism model of the speed variation acquisition section 110 can be a model that reproduces mechanical play of the drive mechanism 30, deflection of components, and the like based on publicly known technology. By calculating the speed variation of the drive mechanism 30 using the mechanism model, the laser head 20, the drive mechanism 30, or the workpiece W is not damaged due to inappropriate operation, and laser processing can be optimized. In addition, the mechanism model can also be used to correct the operation of the drive mechanism 30 based on publicly known technology.

[0036] The mechanism delay time calculation section 111 calculates a delay time with respect to the positioning command of the drive mechanism 30, that is, a mechanism delay time, based on the speed variation of the drive mechanism 30 acquired by the speed variation acquisition section 110. The mechanism delay time is calculated as a time until the speed of the drive mechanism 30 becomes substantially equal to the speed according to the positioning command from the output of the positioning command.

[0037] The mechanism delay time calculation section 111 can also find the time until the speed of the drive mechanism 30 becomes equal for all positioning commands at times within a range in which the speed according to the positioning command changes, and calculate them as an average value. In addition, the mechanism delay time calculation section 111 can also calculate the mechanism delay time only for an instant at which the speed according to the positioning command is fixed. Generally, laser processing is performed in a state in which the speed of the drive mechanism 30 is maintained to be fixed. Therefore, if the mechanism delay time is calculated for an instant at which the speed according to the positioning command is fixed, the entire processing can be easily and accurately optimized.

[0038] The command time difference setting section 112 sets a time difference between the reference time of the laser command and the reference time of the positioning command, that is, a command time difference td, based on the mechanism delay time tl calculated by the mechanism delay time calculation section 111 and the laser delay time t2 calculated by the laser delay time calculation section 107, for an interval in which the laser is emitted is specified in the processing program. Specifically, by setting the command time difference td to a value (tl-t2) obtained by subtracting the laser delay time t2 from the mechanism delay time tl, it is possible to irradiate the laser to a faithful position through the processing program.

[0039] As above, the numerical control device 100 sets the command time difference td in the command time difference setting section 112 in a manner that enables accurate reproduction of the machining program, based on the mechanism delay time tl calculated by the mechanism delay time calculation section 111 and the laser delay time t2 accurately calculated in the laser delay time calculation section 107 by simulating the output change of the laser oscillator 10 using the oscillator model in the laser output calculation section 106, and thus the operator is able to perform ideal laser machining without being aware of the difference in machining kind or the like. As an example, in the case of performing contour cutting that cuts the workpiece W into a prescribed shape, the laser head 20 is sometimes stopped at the end point of the cutting, but by setting the command time difference td that takes into account the mechanism delay time tl that represents the delay of the laser head 20 reaching the end point and the laser delay time t2 that represents the delay of the output of the laser stopping, it is possible to prevent cutting residue of the workpiece W.

[0040] Next, the time difference setting device of the present application will be described. Figure 2 is a block diagram that represents the structure of the laser machining system 1A that is provided with the time difference setting device 200 of one embodiment of the present disclosure. Further, in the following description, the same reference numerals are sometimes affixed to the same constituent elements as the embodiment explained earlier and repeated description is omitted.

[0041] The laser machining system 1A of the present embodiment is provided with: a laser oscillator 10 that generates laser light; a laser head 20 that emits the laser light; a drive mechanism 30 that positions the relative position of the laser head 20 and a workpiece W; a numerical control device 100A that controls the laser oscillator 10 and the drive mechanism 30 based on a machining program; and a time difference setting device 200 that sets a command time difference.

[0042] The numerical control device 100A is provided with: a main storage section 101 that stores a machining program or the like; a control section 121 that generates a laser command for the laser oscillator 10 and a positioning command for the drive mechanism 30 based on the machining program or the like stored by the main storage section 101; and a first transmission section 122 that transmits and receives information between the time difference setting device 200.

[0043] Figure 2 The numerical control device 100A of the laser machining system 1A of the present embodiment also realizes the same as the numerical control device 100 of the laser machining system 1 of the present embodiment by causing a computer device to execute an appropriate control program. Figure 1 The numerical control device 100A of the laser machining system 1A of the present embodiment also realizes the same as the numerical control device 100 of the laser machining system 1 of the present embodiment by causing a computer device to execute an appropriate control program.

[0044] The structure of the control section 121 can be the same as in the numerical control device of a conventional laser machining system. As an example, the control section 121 is configured to have a CPU, a ROM, a RAM, and the like, and the CPU executes a control program stored in the ROM to function as a laser command generation section, a positioning command generation section, and the like. Figure 1The program analysis section 102, the interpolation section 103, the laser command generation section 104, and the positioning command generation section 108 of the numerical control device 100 of the laser processing system 1A are the same structures as those of the numerical control device 100 of the laser processing system 1.

[0045] The first transfer section 122 transmits information stored in the main storage section 101 to the time difference setting device 200, and stores information transmitted from the time difference setting device 200 to the main storage section 101.

[0046] The time difference setting device 200 sets the command time difference between the laser command and the positioning command in the numerical control device 100A. The time difference setting device 200 can be realized, for example, by causing a computer device having a memory, a CPU, an input / output interface, and the like to execute an appropriate control program. As a specific example, the time difference setting device 200 can be realized as one function of a manager computer that monitors the states of a plurality of laser processing systems. In this way, by providing the time difference setting device 200 that is independent of the numerical control device 100A, it is possible to comparatively easily change an existing device into a laser processing system 1A that can perform more accurate laser processing.

[0047] The time difference setting device 200 has a sub storage section 201, a second transfer section 202, the program analysis section 102, the interpolation section 103, the laser command generation section 104, the laser output calculation section 106, the laser delay time calculation section 107, the positioning command generation section 108, the speed change acquisition section 110, the mechanism delay time calculation section 111, and the command time difference setting section 112. These Figure 2 The program analysis section 102, the interpolation section 103, the laser command generation section 104, the laser output calculation section 106, the laser delay time calculation section 107, the positioning command generation section 108, the speed change acquisition section 110, the mechanism delay time calculation section 111, and the command time difference setting section 112 of the time difference setting device 200 of the laser processing system 1A are the same structures as those of the numerical control device 100 of the laser processing system 1. Figure 1 The program analysis section 102, the interpolation section 103, the laser command generation section 104, the laser output calculation section 106, the laser delay time calculation section 107, the positioning command generation section 108, the speed change acquisition section 110, the mechanism delay time calculation section 111, and the command time difference setting section 112 of the time difference setting device 200 of the laser processing system 1A are the same structures as those of the numerical control device 100 of the laser processing system 1.

[0048] The sub storage section 201 stores the processing program received from the numerical control device 100A and the command time difference calculated by the command time difference setting section 112.

[0049] The second transfer section 202 stores information transmitted from the numerical control device 100A in the sub storage section 201, and transmits the command time difference stored in the sub storage section 201 to the numerical control device 100A.

[0050] Figure 2 The laser processing system 1A will Figure 1 In the laser processing system 1, the components for setting the command time difference are configured as independent devices, and a first transmission unit 122, a secondary storage unit 201, and a second transmission unit 202 are added for the separation of the devices. Therefore, in Figure 2 In the laser processing system 1A, ideal laser processing can also be achieved by setting the instruction time difference in a way that can accurately reproduce the processing program.

[0051] The embodiments of this disclosure have been described above, but the present invention is not limited to the embodiments described above. Furthermore, the effects described in the above embodiments are merely examples of the most preferred effects produced by the present invention, and the effects of the present invention are not limited to the effects described in the above embodiments.

[0052] Symbol Explanation

[0053] 1.1A Laser Processing System

[0054] 10 laser oscillators

[0055] 20 laser heads

[0056] 30 drive mechanism

[0057] 100, 100A numerical control device

[0058] 101 Main Storage Unit

[0059] 102 Program Analysis Department

[0060] 103 Interpolation Section

[0061] 104 Laser Command Generation Unit

[0062] 105 Laser Command Switching Unit

[0063] 106 Laser Output Calculation Unit

[0064] 107 Laser Delay Time Calculation Department

[0065] 108 Positioning Command Generation Unit

[0066] 109 Positioning Command Switching Unit

[0067] 110 speed change acquisition section

[0068] 111 Institution Delay Time Calculation Department

[0069] 112 Command Time Difference Setting Unit

[0070] 121 Control Department

[0071] 122 First Teleportation Department

[0072] 200 time difference setting means

[0073] 201 sub storage section

[0074] 202 second transfer section

Claims

1. A time difference setting device, comprising setting the time difference (i.e., the time difference between the output timing of the laser command and the positioning command, i.e., the command time difference) in a laser processing system including a laser oscillator, a laser head, a drive mechanism, and a numerical control device for generating laser commands for the laser oscillator and positioning commands for the drive mechanism according to a processing program, wherein the laser oscillator generates laser light, the laser head emits the laser light, and the drive mechanism positions the relative position of the laser head and the workpiece, characterized in that... The time difference setting device includes: a speed change acquisition section that acquires a speed change of the drive mechanism with respect to the positioning command based on the machining program; a mechanism delay time calculation section that calculates a mechanism delay time, which is a delay time of positioning of the drive mechanism with respect to the positioning command, based on the speed change of the drive mechanism acquired by the speed change acquisition section; a laser output calculation section that calculates a change in output of the laser oscillator with respect to the laser command based on the machining program using an oscillator model that simulates an operation of the laser oscillator; a laser delay time calculation section that calculates a laser delay time, which is a delay time of output of the laser oscillator with respect to the laser command, based on the change in output of the laser oscillator calculated by the laser output calculation section; and a command time difference setting section that sets the command time difference with respect to an interval in which emission of the laser is specified in the machining program based on the mechanism delay time calculated by the mechanism delay time calculation section and the laser delay time calculated by the laser delay time calculation section.

2. The time difference setting device according to claim 1, wherein the speed change acquisition section calculates the speed change of the drive mechanism with respect to the positioning command using a mechanism model that simulates an operation of the drive mechanism.

3. The time difference setting device according to claim 1 or 2, wherein the mechanism delay time calculation section calculates the mechanism delay time only with respect to an instant at which a speed according to the positioning command becomes fixed.

4. A numerical control device that generates a laser command for a laser oscillator and a positioning command for a driving mechanism that positions a relative position of a laser head that emits a laser and a workpiece, according to a machining program, in a laser processing system that has the laser oscillator, the laser head, and the driving mechanism, characterized by, The numerical control device includes: a speed change acquisition section that acquires a speed change of the drive mechanism with respect to the positioning command based on the machining program; a mechanism delay time calculation section that calculates a mechanism delay time, which is a delay time of positioning of the drive mechanism with respect to the positioning command, based on the speed change of the drive mechanism acquired by the speed change acquisition section; a laser output calculation section that calculates a change in output of the laser oscillator with respect to the laser command based on the machining program using an oscillator model that simulates an operation of the laser oscillator; a laser delay time calculation section that calculates a laser delay time, which is a delay time of output of the laser oscillator with respect to the laser command, based on the change in output of the laser oscillator calculated by the laser output calculation section; and a command time difference setting section that sets the command time difference, which is a time difference in output timing of the laser command with respect to the positioning command, with respect to an interval in which emission of the laser is specified in the machining program based on the mechanism delay time calculated by the mechanism delay time calculation section and the laser delay time calculated by the laser delay time calculation section.

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