Numerical control device and numerical control program

Abstract

The present invention makes it possible to correct a gap amount and correct a laser irradiation position on a machining surface.　This numerical control device controls a machine tool. The machine tool performs relative movement between a machining nozzle 72 and workpiece 82, and emits a laser toward a machining surface S of the workpiece 82 from the machining nozzle 72, thereby laser machining the machining surface S. The numerical control device acquires a gap amount G as the shortest distance from the machining nozzle 72 to the machining surface S. The numerical control device computes a normal direction sZ of the machining surface S, and moves the machining nozzle 72 and the workpiece 82 in a relative manner in the normal direction sZ so to compute a normal direction movement amount V for setting the gap amount G to a desired gap amount Go. The numerical control device moves the machining nozzle 72 and the workpiece 82 in a relative manner in the normal direction sZ on the basis of the computed normal direction movement amount V, thereby correcting the gap amount G to the desired gap amount Go.

Description

[Technical Field]

[0001] The present disclosure relates to a numerical control device for controlling a machine tool. [Background technology]

[0002] Some machine tools perform laser processing of a processing surface by moving a processing nozzle and a workpiece relative to each other and irradiating a laser beam from the processing nozzle toward the processing surface of the workpiece.

[0003] Among the numerical control devices that control such machine tools, there are those that detect the "gap amount" as the shortest distance from the machining nozzle to the machining surface, and correct the gap amount to the desired gap amount using feedback control based on the detected gap amount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-111661 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have focused on the fact that the following problems may occur: Hereinafter, the two-dimensional direction along the processing surface will be referred to as the "processing surface direction," the direction perpendicular to the processing surface will be referred to as the "normal direction," and the direction of laser irradiation from the processing nozzle will be referred to as the "irradiation direction."

[0006] In laser processing, for example, in the case of groove processing to form a V-shaped groove in cross section, the laser may be irradiated with the irradiation direction tilted relative to the normal direction. In this case, the workpiece and the processing nozzle may deviate from the desired relative position, resulting in a deviation in the gap size from the desired gap size. In this state, if the relative position between the workpiece and the processing nozzle is controlled in the direction of the processing surface, the relative position between the processing nozzle and the workpiece will deviate in the normal direction from the desired relative position. Furthermore, because the irradiation direction is tilted relative to the normal direction, this deviation in the normal direction will also cause the laser irradiation position on the processing surface to deviate from the desired irradiation position.

[0007] Even if the gap amount is corrected by moving the machining nozzle and workpiece relatively in the irradiation direction from this state, only the gap amount is corrected to the desired gap amount, and the laser irradiation position on the machining surface remains in a shifted position and is not corrected to the desired irradiation position, because the direction of the relative movement is the irradiation direction.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to make it possible to correct the laser irradiation position on the processing surface in addition to correcting the gap amount. [Means for solving the problem]

[0009] The numerical control device of the present disclosure includes: A numerical control device that controls a machine tool that performs laser processing on a processing surface of the workpiece by moving a processing nozzle and a workpiece relative to each other and irradiating a laser from the processing nozzle toward the processing surface of the workpiece, a gap amount acquiring unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface; a normal calculation unit that calculates a normal direction of the processing surface; a movement amount calculation unit that calculates a normal direction movement amount as a movement amount for relatively moving the machining nozzle and the workpiece in the calculated normal direction to make the gap amount a desired gap amount; a gap correction unit that corrects the gap amount to the desired gap amount by relatively moving the machining nozzle and the workpiece in the normal direction based on the calculated normal direction movement amount; It has.

[0010] According to the numerical control device disclosed herein, when correcting the gap amount, the machining nozzle and the workpiece are moved relatively in the normal direction of the machining surface rather than in the laser irradiation direction, thereby correcting the gap amount and also correcting the irradiation position on the machining surface.

[0011] The numerical control program of the present disclosure is Computer, a numerical control device that controls a machine tool that performs laser processing on a processing surface of the workpiece by moving a processing nozzle and the workpiece relative to each other and irradiating a laser beam from the processing nozzle toward the processing surface of the workpiece; A numerical control program that functions as The computer further comprises: a gap amount acquiring unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface; a normal calculation unit that calculates a normal direction of the processing surface; a movement amount calculation unit that calculates a normal direction movement amount as a movement amount for relatively moving the machining nozzle and the workpiece in the calculated normal direction to make the gap amount a desired gap amount; a gap correction unit that corrects the gap amount to the desired gap amount by relatively moving the machining nozzle and the workpiece in the normal direction based on the calculated normal direction movement amount; Function as.

[0012] The numerical control program of the present disclosure allows a computer to function as the numerical control device of the present disclosure, thereby correcting the irradiation position on the processing surface as well as the gap amount, similar to the case of the numerical control device of the present disclosure. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a numerical control device according to a first embodiment. [Figure 2] FIG. 10 is a side view showing a state in which a laser is obliquely irradiated onto a processing surface. [Figure 3] FIG. 10 is a side view showing a case where the workpiece is displaced in the normal direction under the circumstances. [Figure 4] FIG. 10 is a side view showing gap correction in a comparative example. [Figure 5] FIG. 4 is a side view showing gap correction in the present embodiment. [Figure 6] FIG. 2 is a schematic view showing the numerical control device from a different perspective than that of FIG. 1. [Figure 7] FIG. 10 is a schematic diagram showing a numerical control device according to a second embodiment. [Figure 8] FIG. 10 is a side view showing a state in which the first machining surface is selected as the current machining surface. [Figure 9] FIG. 10 is a side view showing a state in which the second machining surface is selected as the current machining surface. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments and can be appropriately modified and implemented within the scope of the present disclosure.

[0015] [First embodiment] First, the configuration of a numerical control device 50 of this embodiment will be described with reference to Fig. 1. The numerical control device 50 controls a machine tool 90 based on commands based on numerical information. Hereinafter, the three mutually orthogonal directions will be referred to as the "X direction," "Y direction," and "Z direction." Specifically, for example, the X direction and the Y direction are two directions that intersect at right angles in a horizontal plane, and the Z direction is the vertical direction.

[0016] The machine tool 90 has a nozzle holder 71 that holds a machining nozzle 72 and a workpiece holder 81 that holds a workpiece 82. The machine tool 90 moves the nozzle holder 71 and the workpiece holder 81 relative to each other, thereby moving the machining nozzle 72 and the workpiece 82 relative to each other. Specifically, the relative movements include all or some of the following: relative movement in the X direction, relative movement in the Y direction, relative movement in the Z direction, relative movement around the X direction, relative movement around the Y direction, and relative movement around the Z direction. Each of these relative movements may be performed by moving the machining nozzle 72, by moving the workpiece 82, or by moving both the machining nozzle 72 and the workpiece 82.

[0017] The machine tool 90 performs laser machining by irradiating the workpiece 82 with a laser beam Lb from the machining nozzle 72. Hereinafter, the direction in which the laser beam Lb is irradiated by the machining nozzle 72 will be referred to as the "irradiation direction I." Hereinafter, the surface of the workpiece 82 onto which the laser beam Lb is irradiated will be referred to as the "machining surface S," the two-dimensional directions along the machining surface S will be referred to as the "machining surface directions sX, sY," and the normal direction to the machining surface S will be referred to as the "normal direction sZ." Hereinafter, the shortest distance between the tip of the machining nozzle 72 and the machining surface S, that is, the distance in the normal direction sZ, will be referred to as the "gap amount G."

[0018] The processing nozzle 72 has a gap amount detection device 78 for detecting the gap amount G. The gap amount detection device 78 detects the gap amount G based on, for example, the electrostatic capacitance between the tip of the processing nozzle 72 and the workpiece 82.

[0019] The numerical control device 50 is configured to allow a user or the like to input a machining program, and controls the machine tool 90 based on the input machining program. The numerical control device 50 has an analysis unit 21, a processing unit 22, and a drive unit 27. The analysis unit 21 analyzes the input machining program. The processing unit 22 calculates the amount of movement of the nozzle holder 71 and the workpiece holder 81 to position the machining nozzle 72 and the workpiece 82 relative to each other as desired, based on the analysis result by the analysis unit 21. The drive unit 27 outputs an operation command to the machine tool 90 based on the calculation result by the processing unit 22.

[0020] The numerical control device 50 further has a gap amount acquisition unit 33 and a gap correction unit 36. The gap amount acquisition unit 33 acquires the gap amount G detected by the gap amount detection device 78 from the gap amount detection device 78. The gap correction unit 36 ​​performs feedback control or the like based on the gap amount G acquired by the gap amount acquisition unit 33, thereby correcting the gap amount G to a desired gap amount Go.

[0021] Next, the problems to be solved in this embodiment will be described with reference to FIGS.

[0022] As shown in FIG. 2, in laser processing, for example, in groove processing to form a V-shaped groove in cross section, the laser may be irradiated with the irradiation direction I inclined with respect to the normal direction sZ. In this case, the workpiece 82 and the processing nozzle 72 may deviate from the desired relative position, causing the gap amount G to deviate from the desired gap amount Go. In this state, when the relative position between the workpiece 82 and the processing nozzle 72 is controlled in the processing surface directions sX and sY, the relative position of the workpiece 82 with respect to the processing nozzle 72 deviates from the desired position 82o shown by the dashed line in FIG. 3 to the position (82) shown by the solid line in FIG. 3. In other words, the relative position between the processing nozzle 72 and the workpiece 82 deviates in the normal direction sZ from the desired relative position. Furthermore, because the irradiation direction I is inclined with respect to the normal direction sZ, this deviation in the normal direction sZ also causes the laser irradiation position P on the processing surface S to deviate from the desired irradiation position Po.

[0023] From this state, for example, as in the comparative example shown in Fig. 4, it is assumed that the gap amount G is corrected by relatively moving the machining nozzle 72 and the workpiece 82 in the irradiation direction I. In this case, the gap amount G is only corrected to the desired gap amount Go, and the irradiation position P on the machining surface S remains in a shifted position and is not corrected to the desired irradiation position Po because the direction of the relative movement is the irradiation direction I.

[0024] 1, the numerical control device 50 further includes a normal calculation unit 44 and a movement amount calculation unit 45. The normal calculation unit 44 recognizes the rotation angle θ of the workpiece 82 from a predetermined reference state based on the machining program, and calculates the normal direction sZ.

[0025] 2, the normal calculation unit 44 calculates the normal direction sZ based on a reference normal direction sZo, which is the normal direction sZ when the workpiece 82 is in a reference state, and a rotation angle θ of the workpiece 82 from the reference state based on the machining program. In other words, the direction obtained by rotating the reference normal direction sZo by the rotation angle θ becomes the normal direction sZ.

[0026] More specifically, for example, as shown in Figure 2, assume that the Z direction is the reference normal direction sZo and the workpiece 82 is rotated around the X direction. In this case, the unit vector (Xu, Yu, Zu) of the normal direction sZ, i.e., a vector with an absolute value of "1", can be expressed as in the following equation 1. The normal calculation unit 44 calculates this unit vector (Xu, Yu, Zu) to determine the normal direction sZ.

[0027]

number

[0028] The movement amount calculation unit 45 calculates a "normal direction movement amount V" as a relative movement amount in the normal direction sZ between the processing nozzle 72 and the workpiece 82 for correcting the gap amount G shown in Fig. 3 to the desired gap amount Go. Specifically, the normal direction movement amount V can be calculated from, for example, the difference between the gap amount G and the desired gap amount Go and the angle of the irradiation direction I with respect to the normal direction sZ.

[0029] The gap correction unit 36 ​​calculates the normal direction movement vector (Xv, Yv, Zv) by multiplying the unit vector (Xu, Yu, Zu) = (0, -sinθ, cosθ) shown in the above equation (1) by the normal direction movement amount V, as shown in the following equation (2).

[0030]

number

[0031] The gap correction unit 36 ​​operates the drive unit 27 to move the processing nozzle 72 and the workpiece 82 relatively in the X, Y, and Z directions by the amount of each component of this normal direction movement vector (Xv, Yv, Zv). As a result, the processing nozzle 72 and the workpiece 82 move relatively in the normal direction sZ by the normal direction movement amount V, as shown in Fig. 5. As a result, the gap amount G is corrected to the desired gap amount Go, and the laser irradiation position P on the processing surface S is also corrected to the desired irradiation position Po.

[0032] 6, the numerical control device 50 shown above is mainly composed of, for example, a computer Cp and a numerical control program 50p. The computer Cp has a CPU, RAM, ROM, etc. The numerical control program 50p is a program for causing the computer Cp to function as the numerical control device 50 in cooperation with the computer Cp. The numerical control program 50p has an analysis program 21p, a processing program 22p, a drive program 27p, a normal calculation program 44p, a movement amount calculation program 45p, a gap amount acquisition program 33p, and a gap correction program 36p.

[0033] The analysis program 21p causes the computer Cp to function as the analysis unit 21. The processing program 22p causes the computer Cp to function as the processing unit 22. The drive program 27p causes the computer Cp to function as the drive unit 27. The normal calculation program 44p causes the computer Cp to function as the normal calculation unit 44. The movement amount calculation program 45p causes the computer Cp to function as the movement amount calculation unit 45. The gap amount acquisition program 33p causes the computer Cp to function as the gap amount acquisition unit 33. The gap correction program 36p causes the computer Cp to function as the gap correction unit 36.

[0034] The configuration and effects of this embodiment are summarized below.

[0035] The normal calculation unit 44 calculates the normal direction sZ of the machining surface S. The movement amount calculation unit 45 calculates a "normal direction movement amount V" for moving the machining nozzle 72 and the workpiece 82 relatively in the calculated normal direction sZ to set the gap amount G to the desired gap amount Go. The gap correction unit 36 ​​corrects the gap amount G to the desired gap amount Go by moving the machining nozzle 72 and the workpiece 82 relatively in the normal direction sZ by the calculated normal direction movement amount V. In this way, when correcting the gap amount G, by moving the machining nozzle 72 and the workpiece 82 relatively in the normal direction sZ rather than in the irradiation direction I, not only the gap amount G but also the irradiation position P on the machining surface S can be corrected.

[0036] The normal calculation unit 44 calculates the normal direction sZ based on a reference normal direction sZo, which is the normal direction sZ when the workpiece 82 is in a predetermined reference state, and the rotation angle θ of the workpiece 82 from the reference state based on the machining program. Therefore, the normal direction sZ can be calculated simply and efficiently.

[0037] The numerical control device 50 is mainly composed of a computer Cp and a numerical control program 50p, and the numerical control program 50p causes the computer Cp to function as the numerical control device 50. Therefore, the numerical control device 50 of this embodiment can be implemented using the computer Cp.

[0038] [Second embodiment] Next, a second embodiment will be described with reference to Figures 7 to 9. This embodiment will be described based on the first embodiment, focusing on differences from the first embodiment, and descriptions of the same or similar aspects to the first embodiment will be omitted as appropriate.

[0039] In this embodiment, multiple surfaces of the workpiece 82 are laser-machined. Therefore, as shown in Fig. 7, the workpiece 82 has multiple machining surfaces S. For this reason, the numerical control device 50 further has a current machining surface change unit 43. The current machining surface change unit 43 selects one of the multiple machining surfaces S as the current machining surface Sc based on the preset shape of the workpiece 82 and the rotation angle θ of the workpiece 82 from the reference state.

[0040] Specifically, for example, the workpiece 82 has a quadrangular prism shape with rectangular end faces on the X-direction side. That is, as shown in Fig. 8, the workpiece 82 has a rectangular shape when viewed in the X-direction. When viewed in the X-direction, the workpiece 82 has a first machining surface S1 as the machining surface S on one long side, a second machining surface S2 as the machining surface S on one short side, a third machining surface S3 as the machining surface S on the opposite side of the first machining surface S1, and a fourth machining surface S4 as the machining surface on the opposite side of the second machining surface S2.

[0041] More specifically, for example, similar to the example shown in the first embodiment, a case is assumed in which the Z direction is the reference normal direction sZo and the workpiece 82 is rotated around the X direction. Here, a state in which the "first normal direction sZ1", which is the normal direction sZ of the first machining surface S1, is the reference normal direction sZo, is defined as a "reference state", and the angle of the first normal direction sZ1 with respect to the reference normal direction sZo is defined as the "rotation angle θ of the workpiece 82".

[0042] As shown in Fig. 8, the current machining surface change unit 43 selects the first machining surface S1 as the current machining surface Sc when the rotation angle θ of the workpiece 82 is between -45° and 45°. On the other hand, as shown in Fig. 9, when the rotation angle θ of the workpiece 82 is between 45° and 135°, the current machining surface change unit 43 selects the second machining surface S2 as the current machining surface Sc. Furthermore, when the rotation angle θ of the workpiece 82 is between 135° and 225°, the current machining surface change unit 43 selects the third machining surface S3 as the current machining surface Sc. Furthermore, when the rotation angle θ of the workpiece 82 is between 225° and 315°, the current machining surface change unit 43 selects the fourth machining surface S4 as the current machining surface Sc.

[0043] 7 calculates the normal direction sZ of the selected current machining surface Sc. The movement amount calculation unit 45 calculates the normal direction movement amount V to make the gap amount G in the calculated normal direction sZ equal to the desired gap amount Go. The gap correction unit 36 ​​moves the machining nozzle 72 and the workpiece 82 relative to each other in the normal direction sZ of the current machining surface Sc by the calculated normal direction movement amount V. As a result, as in the first embodiment, the gap amount G is corrected to the desired gap amount Go, and the irradiation position P is corrected to the desired irradiation position Po.

[0044] According to this embodiment, the current machining surface change unit 43 selects one of the multiple machining surfaces S as the current machining surface Sc based on the rotation angle θ of the workpiece 82. The normal calculation unit 44 calculates the normal direction sZ of the current machining surface Sc. The gap correction unit 36 ​​moves the machining nozzle 72 and the workpiece 82 relatively in the normal direction sZ of the current machining surface Sc. Therefore, even if the workpiece 82 has multiple machining surfaces S, such as when the workpiece 82 is a square pipe, it can be handled without changing the settings for the machining surfaces S.

[0045] [Other embodiments] The above-described embodiment can be modified, for example, as follows: Instead of being mainly composed of the computer Cp and the numerical control program 50p, the numerical control device 50 may be composed of a device dedicated to numerical control. [Explanation of symbols]

[0046] 44 Normal calculation unit 45 Travel amount calculation section 50 Numerical Control Device 50p Numerical Control Program 72 Processing nozzle 82 Work 90 Machine tools Cp Computer G gap amount Go Desired gap amount S Machining surface sZ normal direction sZo Reference normal direction θ Workpiece rotation angle

Claims

1. A numerical control device that controls, based on a processing program, a machine tool that performs laser processing of a processing surface by performing relative movement between a workpiece having multiple processing surfaces and a processing nozzle and irradiating a laser from the processing nozzle toward the processing surface of the workpiece, a current machining surface change unit that selects one of the plurality of machining surfaces as a current machining surface based on a rotation angle of the workpiece; a gap amount acquiring unit that acquires a gap amount as the shortest distance from the processing nozzle to the current processing surface; a normal calculation unit that calculates the normal direction of the current machining surface based on a reference normal direction as a normal direction of the current machining surface when the workpiece is in a predetermined reference state and a rotation angle of the workpiece from the reference state based on the machining program; a movement amount calculation unit that calculates a normal direction movement amount as a movement amount for relatively moving the machining nozzle and the workpiece in the calculated normal direction to make the gap amount a desired gap amount; a gap correction unit that corrects the gap amount to the desired gap amount by linearly moving the processing nozzle and the workpiece relative to each other in the normal direction based on the normal direction movement amount calculated by the movement amount calculation unit while maintaining the irradiation direction in which the laser is irradiated from the processing nozzle in a direction oblique to the normal direction; A numerical control device having:

2. Computer, a numerical control device that controls, based on a machining program, a machine tool that performs laser processing on a machining surface by moving a workpiece having a plurality of machining surfaces relative to a machining nozzle and irradiating a laser beam from the machining nozzle toward the machining surface of the workpiece; A numerical control program that functions as The computer further comprises: a current machining surface change unit that selects one of the plurality of machining surfaces as a current machining surface based on a rotation angle of the workpiece; a gap amount acquiring unit that acquires a gap amount as the shortest distance from the processing nozzle to the current processing surface; a normal calculation unit that calculates the normal direction of the current machining surface based on a reference normal direction as a normal direction of the current machining surface when the workpiece is in a predetermined reference state and a rotation angle of the workpiece from the reference state based on the machining program; a movement amount calculation unit that calculates a normal direction movement amount as a movement amount for relatively moving the machining nozzle and the workpiece in the calculated normal direction to make the gap amount a desired gap amount; a gap correction unit that corrects the gap amount to the desired gap amount by linearly moving the processing nozzle and the workpiece relative to each other in the normal direction based on the normal direction movement amount calculated by the movement amount calculation unit while maintaining the irradiation direction in which the laser is irradiated from the processing nozzle in a direction oblique to the normal direction; A numerical control program that functions as a

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