Numerical controller and numerical control program

Abstract

The irradiation position of the laser beam on the processing surface can be corrected together with the correction of the gap amount. A numerical controller controls a machine tool. The machine tool performs relative movement between the machining nozzle (72) and the workpiece (82), and performs laser machining on a machining surface (S) of the workpiece (82) by irradiating laser light from the machining nozzle (72) toward the machining surface (S). The numerical controller acquires a gap amount (G) that is the shortest distance from the machining nozzle (72) to the machining surface (S). The numerical controller calculates a normal direction (sZ) of the machining surface (S), and calculates a normal direction movement amount (V) for moving the machining nozzle (72) and the workpiece (82) relative to each other in the normal direction (sZ) so that the clearance amount (G) becomes a desired clearance amount (Go). The numerical controller corrects the clearance amount (G) to a desired clearance amount (Go) by relatively moving the machining nozzle (72) and the workpiece (82) in the normal direction (sZ) on the basis of the calculated normal direction movement amount (V).

Description

Technical Field

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

[0002] Some machine tools perform laser processing on a processing surface by irradiating a processing nozzle with a laser beam toward the processing surface of the workpiece while relatively moving the processing nozzle and the workpiece.

[0003] In a numerical control device that controls such a machine tool, a "gap amount" that is the shortest distance from a machining nozzle to a machining surface is detected, and the gap amount is corrected to a desired gap amount by feedback control based on the detected gap amount.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-111661 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present inventors have focused on the following problems that may occur: Hereinafter, the two-dimensional direction along the processing surface is referred to as the "processing surface direction", the direction perpendicular to the processing surface is referred to as the "normal direction", and the irradiation direction of the laser from the processing nozzle is referred to as the "irradiation direction".

[0009] In laser processing, for example, in the case of groove processing to form a V-shaped groove in cross-section, the laser is sometimes irradiated with the irradiation direction tilted relative to the normal direction. In this case, the workpiece and the processing nozzle sometimes deviate from the desired relative position, causing the gap amount to deviate from the desired gap amount. In this state, if the relative position of the workpiece and the processing nozzle is controlled in the processing surface direction, the relative position of the processing nozzle and the workpiece deviates from the desired relative position in the normal direction. In addition, the irradiation direction is tilted relative to the normal direction, so due to the deviation of the normal direction, the irradiation position of the laser on the processing surface also deviates from the desired irradiation position.

[0010] Even if the processing nozzle and the workpiece are moved relative to each other in the irradiation direction to correct the gap amount from this state, the gap amount is only corrected to the desired gap amount. Since the direction of the relative movement is the irradiation direction, the irradiation position of the laser on the processing surface is maintained in a deviated position and is not corrected to the desired irradiation position.

[0011] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to enable correction of the irradiation position of a laser beam on a processing surface together with correction of the gap amount.

[0012] Means for solving problems

[0013] The numerical control device disclosed in the present invention controls a machine tool, wherein the machine tool performs relative movement between a machining nozzle and a workpiece and irradiates a laser from the machining nozzle to a machining surface of the workpiece, thereby laser machining the machining surface.

[0014] The numerical control device comprises:

[0015] a gap amount acquisition unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface;

[0016] A normal line calculation unit, which calculates the normal line direction of the processing surface;

[0017] 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 so that the gap amount becomes a desired gap amount; and

[0018] The gap correction unit 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.

[0019] According to the numerical control device disclosed in the present invention, when correcting the gap amount, the processing nozzle and the workpiece are relatively moved in the normal direction of the processing surface instead of in the irradiation direction of the laser, thereby being able to correct the irradiation position on the processing surface together with the correction of the gap amount.

[0020] The numerical control program disclosed in the present invention enables a computer to function as a numerical control device, and the numerical control device controls a machine tool, and the machine tool performs relative movement between a processing nozzle and a workpiece, and irradiates a laser from the processing nozzle toward a processing surface of the workpiece, thereby performing laser processing on the processing surface.

[0021] The numerical control program also causes the computer to function as:

[0022] a gap amount acquisition unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface;

[0023] A normal line calculation unit, which calculates the normal line direction of the processing surface;

[0024] 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 so that the gap amount becomes a desired gap amount; and

[0025] The gap correction unit 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.

[0026] According to the numerical control program of the present disclosure, a computer can be made to function as the numerical control device of the present disclosure. Thus, as in the case of the numerical control device of the present disclosure, the irradiation position on the processing surface can be corrected together with the correction of the gap amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram showing a numerical control device according to the first embodiment.

[0028] Figure 2 This is a side view showing a state where a processing surface is irradiated with a laser beam at an angle.

[0029] Figure 3 This is a side view showing how the workpiece deviates in the normal direction in this situation.

[0030] Figure 4 It is a side view showing backlash correction in a comparative example.

[0031] Figure 5 It is a side view showing backlash correction in this embodiment.

[0032] Figure 6 So with Figure 1 A schematic diagram showing a numerical control device from different perspectives.

[0033] Figure 7 It is a schematic diagram showing a numerical control device according to a second embodiment.

[0034] Figure 8 It is a side view showing a state in which the first processing surface is selected as the current processing surface.

[0035] Fig. 9 It is a side view showing a state where the second processing surface is selected as the current processing surface. DETAILED DESCRIPTION

[0036] 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 at all, and can be implemented with appropriate changes within the scope of the present disclosure.

[0037] [First embodiment]

[0038] First, refer to Figure 1The structure of the numerical control device 50 of this embodiment is described. The numerical control device 50 controls the machine tool 90 by instructions based on numerical information. Hereinafter, the three directions orthogonal to each other are referred to as "X direction", "Y direction" and "Z direction". Specifically, for example, the X direction and the Y direction are two directions orthogonal to each other in the horizontal plane, and the Z direction is a vertical direction.

[0039] The machine tool 90 includes a nozzle holding portion 71 that holds a processing nozzle 72 and a workpiece holding portion 81 that holds a workpiece 82. The machine tool 90 moves the processing nozzle 72 and the workpiece 82 relative to each other by moving the nozzle holding portion 71 and the workpiece holding portion 81 relative to each other. Specifically, the relative movement includes all or part of the relative movement in the X direction, the relative movement in the Y direction, the relative movement in the Z direction, the relative movement around the X direction, the relative movement around the Y direction, and the relative movement around the Z direction. Each of these relative movements can be performed by moving the processing nozzle 72, by moving the workpiece 82, or by moving both the processing nozzle 72 and the workpiece 82.

[0040] The machine tool 90 performs laser processing by irradiating the laser light Lb from the processing nozzle 72 to the workpiece 82. Hereinafter, the direction in which the laser light Lb is irradiated by the processing nozzle 72 is referred to as the "irradiation direction I". In addition, in the following, the surface of the workpiece 82 irradiated with the laser light Lb is referred to as the "processing surface S", the two-dimensional directions along the processing surface S are referred to as the "processing surface directions sX, sY", and the normal direction of the processing surface S is referred to as the "normal direction sZ". In addition, in the following, the shortest distance between the front end of the processing nozzle 72 and the processing surface S, that is, the distance in the normal direction sZ is referred to as the "gap amount G".

[0041] The machining nozzle 72 includes a gap amount detecting device 78 for detecting the gap amount G. The gap amount detecting device 78 detects the gap amount G based on, for example, the electrostatic capacitance between the tip of the machining nozzle 72 and the workpiece 82 .

[0042] The numerical control device 50 is configured to allow a user or the like to input a machining program, and to control the machine tool 90 according to the input machining program. The numerical control device 50 includes 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 movement amount of the nozzle holding unit 71 and the workpiece holding unit 81 for bringing the machining nozzle 72 and the workpiece 82 into the desired relative position based on the analysis result of the analysis unit 21. The drive unit 27 outputs an operation command to the machine tool 90 based on the calculation result of the processing unit 22.

[0043] The numerical control device 50 further includes 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 based on the gap amount G acquired by the gap amount acquisition unit 33, thereby correcting the gap amount G to the desired gap amount Go.

[0044] Next, refer to Figure 2 to Figure 4 , the issues to be solved in this embodiment are explained.

[0045] like Figure 2 As shown, in laser processing, for example, in the case of groove processing to form a V-shaped groove in cross-section, the laser is sometimes irradiated with the irradiation direction I tilted relative to the normal direction sZ. In this case, the workpiece 82 and the processing nozzle 72 may deviate from the desired relative position, and the gap amount G may deviate from the desired gap amount Go. In this state, when the relative position of 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 relative to the processing nozzle 72 changes from Figure 3 The desired position 82° shown by the dashed line Figure 3 The position (82) indicated by the solid line in the middle is deviated. That is, the relative position between the processing nozzle 72 and the workpiece 82 deviates from the desired relative position along the normal direction sZ. In addition, the irradiation direction I is inclined relative to the normal direction sZ. Therefore, due to the deviation of the normal direction sZ, the irradiation position P of the laser on the processing surface S also deviates from the desired irradiation position Po.

[0046] From this state, for example Figure 4 As in the case of the comparative example shown in FIG. 1 , the machining nozzle 72 and the workpiece 82 are relatively moved in the irradiation direction I to correct the gap amount G. In this case, by correcting only the gap amount G to the desired gap amount Go, the irradiation position P on the machining surface S is not corrected to the desired irradiation position Po while being maintained at a deviated position because the direction of the relative movement is the irradiation direction I.

[0047] In order to solve the above problems, Figure 1 As shown, the numerical control device 50 further includes a normal line calculation unit 44 and a movement amount calculation unit 45. The normal line 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 line direction sZ.

[0048] Specifically, if Figure 2 As shown, the normal line calculation unit 44 calculates the normal line direction sZ based on the reference normal line direction sZo, which is the normal line direction sZ when the workpiece 82 is in the reference state, and the rotation angle θ of the workpiece 82 from the reference state based on the machining program. That is, the reference normal line direction sZo is rotated by the rotation angle θ to become the normal line direction sZ.

[0049] More specifically, for example, Figure 2 As shown, the Z direction is the reference normal direction sZo, and the workpiece 82 is rotated about the X direction. The unit vector (Xu, Yu, Zu) of the normal direction sZ in this case, that is, a vector with an absolute value of "1", can be expressed as shown in the following mathematical formula 1. The normal calculation unit 44 calculates the normal direction sZ by calculating the unit vector (Xu, Yu, Zu).

[0050] [Mathematical formula 1]

[0051]

[0052] The movement amount calculation unit 45 calculates Figure 3 The gap amount G shown is corrected to the desired gap amount Go, which is the "normal direction movement amount V" of the relative movement amount of the machining nozzle 72 and the workpiece 82 in the normal direction sZ. Specifically, the normal direction movement amount V can be obtained, for example, based on the difference between the gap amount G and the desired gap amount Go and the angle of the irradiation direction I relative to the normal direction sZ.

[0053] As shown in the following mathematical formula 2, the gap correction unit 36 ​​calculates the normal direction movement vector (Xv, Yv, Zv) as the value obtained by multiplying the unit vector (Xu, Yu, Zu) = (0, -sinθ, cosθ) shown in the above mathematical formula 1 by the normal direction movement amount V.

[0054] [Mathematical formula 2]

[0055]

[0056] The gap correction unit 36 ​​acts on the driving unit 27 to relatively move the machining nozzle 72 and the workpiece 82 in the X direction, the Y direction, and the Z direction by the amount of each component of the normal direction movement vector (Xv, Yv, Zv). Figure 5 As shown, the machining nozzle 72 and the workpiece 82 are relatively moved in the normal direction sZ by the normal direction movement amount V. Thus, the gap amount G is corrected to the desired gap amount Go, and the irradiation position P of the laser on the machining surface S is also corrected to the desired irradiation position Po.

[0057] like Figure 6As shown, 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, a RAM, a ROM, etc. The numerical control program 50p is a program for making the computer Cp function as the numerical control device 50 by cooperating with the computer Cp. The numerical control program 50p includes: an analysis program 21p, a processing program 22p, a driver program 27p, a normal line calculation program 44p, a movement amount calculation program 45p, a gap amount acquisition program 33p, and a gap correction program 36p.

[0058] 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 driver program 27p causes the computer Cp to function as the driver unit 27. The normal line calculation program 44p causes the computer Cp to function as the normal line 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.

[0059] The structure and effects of this embodiment are summarized below.

[0060] The normal line calculation unit 44 calculates the normal line direction sZ of the processing surface S. The movement amount calculation unit 45 calculates the "normal line direction movement amount V" for relatively moving the processing nozzle 72 and the workpiece 82 in the calculated normal line direction sZ so that the gap amount G becomes the desired gap amount Go. The gap correction unit 36 ​​relatively moves the processing nozzle 72 and the workpiece 82 in the normal line direction sZ by the calculated normal line direction movement amount V, thereby correcting the gap amount G to the desired gap amount Go. In this way, when correcting the gap amount G, by relatively moving the processing nozzle 72 and the workpiece 82 in the normal line direction sZ instead of relatively moving them in the irradiation direction I, in addition to the gap amount G, the irradiation position P on the processing surface S can also be corrected.

[0061] The normal line calculation unit 44 calculates the normal line direction sZ based on the reference normal line direction sZo which is the normal line 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 line direction sZ can be calculated simply and efficiently.

[0062] 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 the present embodiment can be implemented using the computer Cp.

[0063] [Second embodiment]

[0064] Next, refer to Figure 7 to Figure 9 The second embodiment will be described. This embodiment is based on the first embodiment, and the description will be mainly focused on the points that are different therefrom, and the description of the same or similar points as the first embodiment will be appropriately omitted.

[0065] In this embodiment, laser processing is performed on multiple surfaces of the workpiece 82. Figure 7 As shown, the workpiece 82 has a plurality of machined surfaces S. Therefore, the numerical control device 50 further includes a current machined surface changing unit 43. The current machined surface changing unit 43 selects one of the plurality of machined surfaces S as the current machined surface Sc based on the preset shape of the workpiece 82 and the rotation angle θ of the workpiece 82 from the reference state.

[0066] Specifically, for example, the workpiece 82 is in the shape of a quadrangular prism with both end faces on the X-direction side being rectangular. Figure 8 As shown, the workpiece 82 is rectangular when viewed in the X direction. When viewed in the X direction, the workpiece 82 has: a first processing surface S1 as a processing surface S on a long side, a second processing surface S2 as a processing surface S on a short side, a third processing surface S3 as a processing surface S on the opposite side of the first processing surface S1, and a fourth processing surface S4 as a processing surface on the opposite side of the second processing surface S2.

[0067] More specifically, for example, here, as in the example shown in the first embodiment, it is assumed that the Z direction is the reference normal direction sZo and the workpiece 82 is rotated around the X direction. And, here, the state in which the normal direction sZ of the first machined surface S1, i.e., the "first normal direction sZ1", is the reference normal direction sZo is set as the "reference state", and the angle of the first normal direction sZ1 relative to the reference normal direction sZo is set as the "rotation angle θ of the workpiece 82".

[0068] like Figure 8 As shown in FIG. 1 , when the rotation angle θ of the workpiece 82 is between −45° and 45°, the current machined surface changing unit 43 selects the first machined surface S1 as the current machined surface Sc. Fig. 9 As shown, when the rotation angle θ of the workpiece 82 is 45° to 135°, the second processing surface S2 is selected as the current processing surface Sc. In addition, when the rotation angle θ of the workpiece 82 is 135° to 225°, the third processing surface S3 is selected as the current processing surface Sc. In addition, when the rotation angle θ of the workpiece 82 is 225° to 315°, the fourth processing surface S4 is selected as the current processing surface Sc.

[0069] Figure 7The normal line calculation unit 44 shown in the figure calculates the normal line direction sZ of the selected current processing surface Sc. The movement amount calculation unit 45 calculates the normal line direction movement amount V for making the calculated gap amount G in the normal line direction sZ become the desired gap amount Go. The gap correction unit 36 ​​moves the processing nozzle 72 and the workpiece 82 relatively in the normal line direction sZ of the current processing surface Sc by the calculated normal line direction movement amount V. Thereby, as in the case of 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.

[0070] According to the present embodiment, the current processing surface changing unit 43 selects one of the multiple processing surfaces S as the current processing surface Sc according to the rotation angle θ of the workpiece 82. The normal line calculation unit 44 calculates the normal line direction sZ of the current processing surface Sc. The gap correction unit 36 ​​moves the processing nozzle 72 and the workpiece 82 relative to each other in the normal line direction sZ of the current processing surface Sc. Therefore, even in the case where the workpiece 82 has multiple processing surfaces S, such as when the workpiece 82 is a square tube, it is possible to cope with the situation without changing the setting of the processing surface S.

[0071] [Other embodiments]

[0072] The above-described embodiment can be modified as follows, for example: The numerical control device 50 may be composed of a device dedicated to numerical control instead of being mainly composed of the computer Cp and the numerical control program 50p.

[0073] Explanation of symbols

[0074] 44 Normal calculation unit

[0075] 45 Movement amount calculation unit

[0076] 50 Numerical control device

[0077] 50p Numerical Control Program

[0078] 72 Processing Nozzle

[0079] 82 Workpieces

[0080] 90 Machine Tools

[0081] Cp Computer

[0082] G Clearance

[0083] Go Expected Clearance

[0084] S machining surface

[0085] sZ normal direction

[0086] sZo base normal direction

[0087] θ is the rotation angle of the workpiece.

Claims

1. A numerical control device for controlling a machine tool, wherein the machine tool performs relative movement between a machining nozzle and a workpiece and irradiates a laser from the machining nozzle to a machining surface of the workpiece, thereby laser machining the machining surface, characterized in that: The numerical control device comprises: a gap amount acquisition unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface; A normal line calculation unit, which calculates the normal line 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 so that the gap amount becomes a desired gap amount; as well as The gap correction unit 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.

2. The numerical control device according to claim 1, characterized in that: The numerical control device controls the machine tool according to the machining program. The normal line calculation unit calculates the normal line direction based on a reference normal line direction that is the normal line direction 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.

3. The numerical control device according to claim 1 or 2, characterized in that: The workpiece has a plurality of processing surfaces. The numerical control device comprises: a current machined surface changing unit which selects one of the plurality of machined surfaces as the current machined surface according to the rotation angle of the workpiece; The normal line calculation unit calculates the normal line direction of the current processed surface. The gap correction unit moves the machining nozzle and the workpiece relative to each other in a normal direction of the current machining surface.

4. A numerical control program that causes a computer to function as a numerical control device, the numerical control device controlling a machine tool, the machine tool performing relative movement between a machining nozzle and a workpiece, and irradiating a laser from the machining nozzle toward a machining surface of the workpiece, thereby laser machining the machining surface, characterized in that: The numerical control program also causes the computer to function as: a gap amount acquisition unit that acquires a gap amount as the shortest distance from the processing nozzle to the processing surface; A normal line calculation unit, which calculates the normal line 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 so that the gap amount becomes a desired gap amount; as well as The gap correction unit 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.

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