Laser processing device and laser processing method

Abstract

A control unit of this laser processing device comprises an inclination angle calculation unit, a gap correction amount calculation unit, a processing condition correction amount calculation unit, a processing condition correction unit, and a device control unit. The inclination angle calculation unit calculates an inclination angle between a nozzle opening surface, which is a surface on the workpiece side of a processing nozzle, and a surface of a workpiece at a position for laser processing of the workpiece. The gap correction amount calculation unit calculates a gap correction amount for correcting a set gap amount between the nozzle opening surface and the surface of the workpiece by using the inclination angle and shape data of the processing nozzle. The processing condition correction amount calculation unit calculates a correction amount of a laser processing condition corresponding to the gap correction amount by using processing condition adjustment information indicating a relationship between a change amount of the gap amount and the correction amount of the laser processing condition. The processing condition correction unit corrects the laser processing condition by using the correction amount of the laser processing condition. The device control unit controls an axis movement control unit so that the gap amount after correction becomes the sum of the set gap amount and the gap correction amount.

Description

Laser Processing Apparatus and Laser Processing Method

[0001] The present disclosure relates to a laser processing apparatus and a laser processing method for processing a workpiece by irradiating the workpiece with laser light.

[0002] A laser processing apparatus is an apparatus that processes a workpiece by irradiating the workpiece with laser light emitted from a laser oscillator while supplying assist gas. Processing of the workpiece is performed by removing molten portions formed by the laser light using the assist gas. In this laser processing apparatus, stable and high-quality processing is desired.

[0003] In a laser processing apparatus, it is required to set the focal position of energy irradiation such as laser light to an optimal position according to the thickness of the workpiece to be cut, and to prevent the processing nozzle from coming into contact with the workpiece that has been distorted during cutting. For this reason, laser processing apparatuses perform scanning control that keeps the distance between the tip of the processing nozzle and the surface of the workpiece constant. Further, when the workpiece is a relatively thick steel plate, it is often welded after cutting, and a groove may be formed when cutting the steel plate. In order to allow the laser processing apparatus to be applied to such cutting modes, that is, to enable grooving for forming an inclined cut surface on the workpiece, the laser processing apparatus can incline the processing nozzle from a vertical state relative to the workpiece.

[0004] In addition, laser processing apparatuses can also perform drilling processing. In one example, a vent is formed in a cylindrical workpiece by drilling. Drilling processing includes straight-hole drilling, which forms a hole perpendicular to the surface of the workpiece, and inclined-hole drilling, which forms a hole inclined relative to the surface of the workpiece. When straight-hole drilling and inclined-hole drilling are mixed in a single workpiece, the position of the processing nozzle is controlled to be inclined while keeping the focal position of the laser light constant. At this time, if the processing nozzle comes into contact with the workpiece, there is a problem that the laser processing apparatus or the workpiece may be damaged.

[0005] Patent Document 1 discloses a laser processing apparatus that avoids contact between the processing nozzle and the workpiece. Specifically, in the laser processing apparatus described in Patent Document 1, a reference distance between the processing nozzle and the workpiece is calculated from the tip radius of the processing nozzle of the laser processing apparatus, the clearance between the processing nozzle and the surface of the workpiece, and the inclination angle between the processing nozzle and the workpiece. Then, in the laser processing apparatus described in Patent Document 1, the distance between the processing nozzle and the workpiece is adjusted so that it does not become smaller than the reference distance.

[0006] Japanese Patent Publication No. 2005-081434

[0007] However, the technology described in Patent Document 1 may result in a decrease in laser processing quality. For example, changing the position of the processing nozzle to avoid contact causes the focal point of the laser beam to shift from the surface of the workpiece, resulting in a decrease in laser processing quality. It is also conceivable that the decrease in laser processing quality can be prevented by changing to a processing nozzle of a different shape depending on the processing shape of the workpiece and applying sufficient pressure to the melting area with the laser beam. However, the technology described in Patent Document 1 also has the problem that it cannot control multiple processing nozzle shapes.

[0008] This disclosure has been made in view of the above, and aims to provide a laser processing apparatus that can change the angle between the surface of the workpiece and the nozzle opening surface of the processing nozzle, and that can suppress the deterioration of laser processing quality compared to conventional methods while avoiding contact between the processing nozzle and the workpiece.

[0009] To solve the above-mentioned problems and achieve the objective, the laser processing apparatus of this disclosure comprises a laser oscillator, a table, a processing head, a processing nozzle, an axis movement control unit, and a control unit. The laser oscillator emits laser light. The table holds the workpiece. The processing head irradiates the workpiece with laser light from the laser oscillator. The processing nozzle is provided on the laser light emission end side of the processing head and sprays assist gas at the position where the laser light irradiates the workpiece. The axis movement control unit drives the table or processing head in the directions of the mutually orthogonal X, Y, and Z axes, rotates the table or processing head about an inclination axis in the XY plane formed by the X and Y axes, and rotates the table or processing head about a rotation axis parallel to the Z axis. The control unit controls the laser oscillator and the axis movement control unit. The control unit includes an inclination angle calculation unit, a gap correction amount calculation unit, a processing condition correction amount calculation unit, a processing condition correction unit, and an apparatus control unit. The tilt angle calculation unit calculates the tilt angle between the nozzle opening surface (the workpiece-side surface of the processing nozzle) and the workpiece surface at the laser processing position of the workpiece. The gap correction amount calculation unit uses the tilt angle and the shape data of the processing nozzle to calculate a gap correction amount that corrects the set gap amount between the nozzle opening surface and the workpiece surface. The processing condition correction amount calculation unit uses processing condition adjustment information that shows the relationship between the change in gap amount and the correction amount of the laser processing conditions to calculate a correction amount of the laser processing conditions corresponding to the gap correction amount. The processing condition correction unit corrects the laser processing conditions using the correction amount of the laser processing conditions. The device control unit controls the axis movement control unit so that the corrected gap amount is the sum of the set gap amount and the gap correction amount.

[0010] The laser processing apparatus according to this disclosure is a laser processing apparatus capable of changing the angle between the surface of the workpiece and the nozzle opening surface of the processing nozzle, and has the effect of suppressing the deterioration of laser processing quality compared to conventional methods while avoiding contact between the processing nozzle and the workpiece.

[0011] Figure 1 shows an example of the configuration of a laser processing apparatus. Figure 1 shows an example of the configuration of the drive shaft of the laser processing apparatus shown in Figure 1. Figure 1 shows an example of the configuration of the shaft of the laser processing apparatus shown in Figure 1. Figure 1 shows an example of the procedure for a laser processing method. Figure 2 shows an example of the procedure for a laser processing method. Figure 3 shows an example of the execution of contact avoidance and the occurrence of processing defects by a conventional laser processing apparatus. Figure 4 shows an overview of the procedure for calculating the gap correction amount and correcting the nozzle position in a vertical processing nozzle used in a laser processing apparatus according to Embodiment 1. Figure 5 shows an example of the procedure for correcting the laser processing conditions in a vertical processing nozzle used in a laser processing apparatus according to Embodiment 1. Figure 6 shows an example of the configuration of the processing program generation unit of a laser processing apparatus according to Embodiment 1. Figure 7 shows an example of the configuration of the processing program generation unit. A flowchart showing an example of the processing procedure for the laser processing method according to the illustrated embodiment 1. A flowchart showing an example of the processing procedure for the laser processing method according to the illustrated embodiment 1. An example of the configuration of the inclined processing nozzle used in the laser processing apparatus according to the illustrated embodiment 2. An overview of the procedure for calculating the gap correction amount and correcting the nozzle position in the inclined processing nozzle used in the laser processing apparatus according to the illustrated embodiment 2. An example of the procedure for correcting the laser processing conditions in the inclined processing nozzle used in the laser processing apparatus according to the illustrated embodiment 2. An example of the laser processing conditions when laser processing using the vertical processing nozzle and inclined processing nozzle used in the laser processing apparatus according to the illustrated embodiment 3 A block diagram showing an example of the configuration of a computer system that realizes the control device of the laser processing apparatus according to illustrated embodiments 1 to 3.

[0012] The laser processing apparatus and laser processing method according to embodiments of this disclosure will be described in detail below with reference to the drawings.

[0013] First, we will explain the general configuration of a laser processing apparatus and the laser processing method. We will also use perpendicular hole drilling and inclined hole drilling as examples to explain the problems that arise when laser processing is performed when the workpiece surface and the nozzle opening surface are not parallel. Following this, we will describe an embodiment that can solve these problems.

[0014] Figure 1 shows an example of the configuration of a laser processing apparatus. The laser processing apparatus 10 is a device that laser processes a workpiece W by irradiating the workpiece W with a laser beam, which is laser light L.

[0015] The laser processing apparatus 10 comprises a table 11, a laser oscillator 12, a fiber optic cable 13, a processing head 14, a processing nozzle 15, a processing gas supply unit 16, gas piping 17, an axis movement control unit 18, and a control device 30.

[0016] Table 11 is on which the workpiece W is placed. Table 11 may also have a function for fixing the workpiece W. The shape of the workpiece W may be a flat plate, a cylindrical shape, or other three-dimensional shape.

[0017] The laser oscillator 12 emits laser light L. As an example, the type of laser oscillator 12 that generates the laser light L that the laser processing device 10 irradiates onto the workpiece W is either a fiber laser using a semiconductor laser or a CO2 laser. Also, an example of the wavelength of the laser light L emitted from the laser oscillator 12 is 1070 nm for a fiber laser. The laser light L may be a continuous wave or a pulsed wave.

[0018] The fiber cable 13 transmits the laser light L emitted from the laser oscillator 12 to the processing head 14.

[0019] The processing head 14 irradiates the workpiece W with laser light L from the laser oscillator 12 that has propagated through the fiber cable 13. Although not shown, the processing head 14 has a collimating optical system for parallelizing the laser light L and a focusing lens for focusing the laser light L. The position where the laser light L from the processing head 14 enters the workpiece W is called the processing point P. The processing point P is the position on the workpiece W where processing is being performed.

[0020] The processing nozzle 15 is located on the laser beam L exit end side of the processing head 14 and sprays assist gas at the point where the laser beam L irradiates the workpiece W. In one example, the processing nozzle 15 has an injection port that sprays assist gas around the exit point of the laser beam L of the processing head 14. In this example, a flow path 141 is provided inside the processing head 14 to guide the assist gas to the processing nozzle 15. The assist gas is used to remove molten material and cool the workpiece W during processing in the area including the processing point P of the workpiece W, as well as to suppress oxidation of the workpiece W or to prevent oxidation of the workpiece W. The type of assist gas is selected depending on the purpose of use.

[0021] The processing gas supply unit 16 supplies assist gas to the processing nozzle 15 via gas piping 17. In one example, the processing gas supply unit 16 is located outside the laser processing apparatus 10. The gas piping 17 is connected between the processing gas supply unit 16 and the processing head 14 so that the assist gas from the processing gas supply unit 16 is ejected from the processing nozzle 15.

[0022] The axis movement control unit 18 drives at least one of the machining head 14 and the table 11. In one example, the axis movement control unit 18 includes a drive shaft (not shown), which is a machining shaft directly or indirectly connected to the machining head 14 and the table 11, and a motor (not shown) that drives the drive shaft. The drive shaft is connected to the motor and transmits force from the motor directly or indirectly to the machining head 14 or the table 11. The motor is a motor such as a servo motor.

[0023] Figure 2 is a perspective view showing an example of the configuration of the drive axes of the laser processing apparatus shown in Figure 1. In Figure 2, the X, Y, and Z axes are three axes perpendicular to each other. In one example, the X and Y axes are parallel to the horizontal direction. In one example, the Z axis is parallel to the vertical direction. The B axis is the axis that serves as the center when rotating the workpiece W on the table 11 around an axis parallel to the Y axis. The B axis is also called the inclination axis. The C axis is the axis that serves as the center when rotating the workpiece W on the table 11 around an axis parallel to the Z axis. The C axis is also called the rotation axis. Here, an example with a B axis is shown, but instead of a B axis, an A axis, which is the axis that serves as the center when rotating the workpiece W on the table 11 around an axis parallel to the X axis, may also be provided. In Figure 2, an example is shown in which the workpiece W is supported on the table 11 by a jig 111.

[0024] In the example shown in Figure 2, the machining head 14 has three drive axes and the table 11 has two drive axes. That is, the machining head 14 is provided with three drive axes (not shown) parallel to the X, Y, and Z axes, respectively. Each drive axis is connected to a motor (not shown) and transmits force from the motor directly or indirectly to the machining head 14. The table 11 is provided with two drive axes (not shown) which are the two rotation axes, the B axis and the C axis. Each drive axis is connected to a motor (not shown) and transmits force from the motor directly or indirectly to the table 11. Note that although Figure 2 shows a configuration where the machining head 14 has three drive axes and the table 11 has two drive axes, other configurations are also possible.

[0025] In this manner, the axis movement control unit 18 drives the table 11 or machining head 14 in the directions of the mutually orthogonal X, Y, and Z axes, rotating the table 11 or machining head 14 around the inclination axis in the XY plane formed by the X and Y axes, and rotating the table 11 or machining head 14 around the Z axis.

[0026] Returning to Figure 1, the control device 30 is a device that controls the laser oscillator 12, the processing gas supply unit 16, and the axis movement control unit 18. The control device 30 has a processing program generation unit 31 and a device control unit 33. The control device 30 corresponds to the control unit.

[0027] The processing program generation unit 31 generates a processing program that includes a processing path for laser processing based on workpiece shape data indicating the shape of the workpiece W and processing information including the position, diameter, and angle of holes to be formed in the workpiece W. The processing program is a computer program that processes the workpiece W by irradiating it with laser light L. In one example, the processing program generation unit 31 is composed of Computer Aided Design (CAD) / Computer Aided Manufacturing (CAM).

[0028] The device control unit 33 controls the operation of the laser oscillator 12, the processing gas supply unit 16, and the axis movement control unit 18 according to the laser processing conditions set by the user and the processing program generated by the processing program generation unit 31. Specifically, the device control unit 33 generates a laser output command according to the processing program and controls the laser oscillator 12 based on the laser output command. As a result, the laser beam L with the output based on the laser output command is output at the timing based on the laser output command. The device control unit 33 generates a gas supply command according to the processing program and controls the processing gas supply unit 16 based on the gas supply command. As a result, assist gas of the gas type and flow rate based on the gas supply command is supplied. The device control unit 33 generates axis commands according to the processing program and controls the axis movement control unit 18 based on the axis commands. As a result, the drive of the motors connected to the drive axes of the X, Y, Z, B, and C axes is controlled based on the axis commands, and the drive axes are driven. In other words, the movement of the processing head 14 in the X, Y, and Z axis directions and the rotation of the table 11 around the B and C axes are performed based on the axis commands. In one example, the device control unit 33 is composed of a computerized numerical control (CNC) device.

[0029] In this configuration, the laser processing apparatus 10 performs laser processing on a workpiece W fixed to a table 11 using a jig 111 by irradiating the workpiece W with laser light L, moving the processing head 14 horizontally, and also by rotating or tilting the table 11. This allows laser processing to be performed at any position on the workpiece W and at any angle to the workpiece W. Here, the laser processing is either cutting or drilling. Drilling includes trepanning, which cuts in a circular shape according to the hole diameter, and percussion processing, which is performed by irradiating with laser light L. Percussion processing is also called piercing. At this time, the laser processing apparatus 10 performs laser processing on the workpiece W at any position and angle using each drive shaft and the laser light L. Each drive shaft and the laser light L are controlled by a processing program, i.e., a processing program code, generated by the control device 30.

[0030] Figure 3 is a side view showing an example of the axial configuration of the laser processing apparatus shown in Figure 1. Figure 3 is a view of Figure 2 from the Y-axis direction. The gap amount Zd, which is the distance in the Z-axis direction between the nozzle opening surface 151 and the surface of the workpiece W, is generally set to a few millimeters or less. This allows sufficient pressure to be applied to the melting area by the laser beam L by the assist gas from the processing nozzle 15, and the melted area can be properly discharged to the back surface of the workpiece W.

[0031] When machining the surface of a workpiece W by irradiating it perpendicularly with laser light L, the B-axis, which is the tilt axis of the table 11, is driven so that the angle between the nozzle opening surface 151 and the surface of the workpiece W becomes 0 degrees, and the X-axis, Y-axis, Z-axis of the machining head 14 or the C-axis, which is the rotation axis of the table 11 is driven. When machining the surface of a workpiece W by tilting the laser light L, the B-axis of the table 11 is driven so that the angle between the nozzle opening surface 151 and the surface of the workpiece W becomes a predetermined value, and the X-axis, Y-axis, Z-axis of the machining head 14 or the C-axis of the table 11 is driven.

[0032] Here, we will describe a laser processing method using the laser processing apparatus 10 with this configuration. Here, we will use the case of drilling with the laser processing apparatus 10 as an example. Figures 4 and 5 are flowcharts showing an example of the procedure for the laser processing method.

[0033] First, a 3D model, which is data showing the 3D structure of a workpiece W with holes drawn at arbitrary positions, is input to the machining program generation unit 31 by the user (step S11). Next, the machining program generation unit 31 detects machining shape information, including the position, diameter, and angle of the holes in the 3D model (step S12). Subsequently, the machining program generation unit 31 generates a machining program, including a machining path for drilling, using the machining shape information (step S13).

[0034] Next, when the user sets the laser processing conditions in the control device 30, the control device 30 receives the set laser processing conditions as processing condition information (step S14). The laser processing conditions include the focus, output, frequency, and duty cycle of the laser beam L. Then, the device control unit 33 reads the generated processing program and the processing condition information (step S15).

[0035] Next, the user performs preparations for the machining process in order to start the machining (step S16). Preparations for the machining process include setting up the machining nozzle 15 on the machining head 14, setting the workpiece W on the table 11, and setting the machining origin. After that, the user starts executing the machining program (step S17).

[0036] The axis movement control unit 18 controls the position and orientation of the machining head 14 and table 11 according to the machining program generated by the machining program generation unit 31 (step S18). In the case of drilling, the machining nozzle 15 is positioned at the center of the target hole.

[0037] Next, a piercing process is performed to create through-holes that penetrate both sides of the workpiece W by irradiating it with a laser beam L for a short time (step S19). Specifically, once the processing nozzle 15 is positioned at a designated location, a piercing process is performed which involves melting the workpiece W by irradiating it with laser beam L and discharging the molten area by supplying assist gas. The piercing process is performed to secure a discharge path for the molten area during the trepanning process described later. In one example, the through-hole is formed in the center of the hole to be processed.

[0038] Subsequently, starting from the through-hole created by piercing, the laser beam L is irradiated while moving horizontally by the radius of the hole to be processed, and then trepanning is performed, irradiating the laser along the circumference of the hole (step S20). This completes one hole drilling process. In addition, in order to achieve a small hole diameter, drilling may be performed using only piercing without trepanning. Furthermore, although drilling has been used as an example here, the procedure is generally the same for laser cutting.

[0039] Next, it is checked whether all drilling in the workpiece W has been completed (step S21). If not all drilling has been completed (if the answer is No in step S21), the process returns to step S18, and steps S18 to S20 are repeatedly executed until all drilled holes are formed. If all drilling has been completed (if the answer is Yes in step S21), the execution of the processing program ends (step S22). This completes the laser processing method for drilling.

[0040] In drilling using the laser processing device 10, a single workpiece W may contain a mixture of holes perpendicular to the surface of the workpiece W and holes that are inclined. In laser processing, tracing control using a capacitance sensor is generally performed to control the gap amount Zd between the nozzle opening surface 151 of the processing nozzle 15 and the surface of the workpiece W. Since the capacitance sensor calculates the distance by measuring the capacitance between the nozzle opening surface 151 and the surface of the workpiece W, the capacitance becomes unstable when the angle between the nozzle opening surface 151 and the surface of the workpiece W changes. Therefore, when processing inclined holes, the measurement accuracy of the gap amount Zd decreases. If control is performed with an incorrect measurement of the gap amount Zd, the processing nozzle 15 and the workpiece W may come into contact, damaging the laser processing device 10 or the workpiece W.

[0041] In the technology described in Patent Document 1, contact is avoided by estimating the error from the tracking sensor and moving the position of the processing nozzle 15. However, since the measurement value of the tracking sensor changes even if dross from laser processing adheres to the processing nozzle 15, it is difficult to accurately estimate the error of the tracking sensor.

[0042] Assuming that the gap amount Zd between the nozzle opening surface 151 and the surface of the workpiece W can be accurately estimated, in order to avoid contact between the processing nozzle 15 and the workpiece W, at least one of the processing nozzle 15 and the workpiece W is usually moved in a direction that moves them apart. When the positions of the processing nozzle 15 and the workpiece W move apart, the focal position of the laser beam L changes. This change in the focal position of the laser beam L changes the laser power density, which degrades the laser processing quality.

[0043] Figure 6 illustrates an example of contact avoidance and the occurrence of processing defects in a conventional laser processing device. State A shows the normal vertical processing state. The gap amount in the Z-axis direction between the nozzle opening surface 151 of the processing nozzle 15 and the surface of the workpiece W is Zd, and the focal position of the laser beam L emitted from the processing head 14 is Zf. In this example, the optical axis is the same as the central axis Cn of the processing nozzle 15. In state A, the focal position Zf of the laser beam L is located on the surface of the workpiece W.

[0044] In state B, the workpiece W is tilted such that the machining nozzle 15 and the workpiece W come into contact with each other. Let the tilt angle of the workpiece W at this time be θv.

[0045] In state C, to avoid contact, the machining position is corrected so as to increase the distance between the machining nozzle 15 and the workpiece W in the Z-axis direction compared to state B. When the distance between the machining nozzle 15 and the workpiece W is increased for contact avoidance in this manner, the focal position Zf of the laser beam L deviates from the desired position. In this example, as shown in state A, the desired focal position Zf is on the surface of the workpiece W, but in state C, the focal position Zf is located between the nozzle opening surface 151 of the machining nozzle 15 and the surface of the workpiece W. In this way, when the focal position Zf of the laser beam L deviates from the desired position, the output density of the laser beam L decreases, so the workpiece W cannot be melted, which may cause machining defects. Although the focal position Zf of the laser beam L has been described herein, machining defects may also occur due to other laser machining conditions.

[0046] It should be noted that in the above description, drilling is taken as an example, but the same problem exists in any laser machining performed by changing the angle between the nozzle opening surface 151 and the surface of the workpiece W.

[0047] In view of the above, the following embodiments describe a laser machining apparatus 10 and a laser machining method that correct a machining position commanded when generating a machining program without using a scanning sensor, thereby avoiding contact between the machining nozzle 15 and the workpiece W and suppressing machining defects caused by correction of the machining position. However, it goes without saying that the same effect can be obtained even when a scanning sensor is used, in the case of machining content with few errors of the scanning sensor.

[0048] Embodiment 1. First, a correction process performed by a laser processing apparatus 10 and a laser processing method according to Embodiment 1 will be described. FIG. 7 is a diagram outlining a calculation procedure for a gap correction amount and a correction procedure for a nozzle position in a vertical processing nozzle used in the laser processing apparatus according to Embodiment 1. Here, it is assumed that the processing nozzle 15 is a substantially cylindrical vertical processing nozzle, and the surface of the workpiece W has no irregularities. Further, it is assumed that at the intersection of the surface of the workpiece W and the central axis Cn of the processing nozzle 15, there is a B-axis which is a rotation axis for rotating the workpiece W. The vertical processing nozzle is a processing nozzle suitably used when a cut surface formed by the laser beam L is perpendicular to the surface of the workpiece W. In one example, the vertical processing nozzle is a processing nozzle having a configuration in which a nozzle opening surface 151 is perpendicular to an optical axis, and assist gas is ejected in the optical axis direction. In this example, the optical axis is the same as the central axis Cn of the processing nozzle 15. In Embodiment 1, a profiling sensor is not used. That is, the gap amount Zd is not measured using a profiling sensor. In this specification, the gap refers to the distance between the nozzle opening surface 151 and the surface of the workpiece W on the central axis Cn of the cylindrical processing nozzle 15. Further, the gap amount refers to the distance between the nozzle opening surface 151 and the surface of the workpiece W on the central axis Cn of the cylindrical processing nozzle 15. That is, when a point where the nozzle opening surface 151 intersects the central axis Cn is defined as a nozzle origin On, the gap is the distance between the nozzle origin On on the central axis Cn and the surface of the workpiece W, and the gap amount is said distance.

[0049] State A is a state where there is no angle between the nozzle opening surface 151 and the surface of the workpiece W, that is, a state where the nozzle opening surface 151 and the surface of the workpiece W are parallel to each other. When performing vertical processing such as straight hole machining, laser processing is performed in this state. Laser processing is performed at a position on the surface of the workpiece W separated by the gap amount Zd from the nozzle opening surface 151 of the processing nozzle 15 in accordance with a specified value of the gap amount specified by a user. When laser processing is performed in this state, correction of the gap amount Zd is not performed.

[0050] State B is a state in which there is an angle between the nozzle opening surface 151 and the surface of the workpiece W, and the processing nozzle 15 and the surface of the workpiece W are in contact. The processing nozzle 15 and the workpiece W come into contact depending on the relationship between the radius r of the processing nozzle 15, the gap amount Zd, and the inclination angle θv of the workpiece W. This contact can cause damage to the laser processing device 10 or the workpiece W. In this example, the gap amount Zd has not been corrected.

[0051] State C is a state in which there is an angle between the nozzle opening surface 151 and the surface of the workpiece W, and the gap amount Zd is corrected. In state C, the gap correction amount ΔZ is calculated using the radius r of the processing nozzle 15 and the inclination angle θv of the workpiece W by the following equation (1). Then, by moving the processing nozzle 15 in the direction of the +Z axis, that is, away from the workpiece W, using this gap correction amount ΔZ, contact between the processing nozzle 15 and the workpiece W is avoided. By avoiding contact between the processing nozzle 15 and the workpiece W, stable laser processing becomes possible.

[0052] ΔZ=r・tanθv...(1)

[0053] As described above, without using a tracking sensor, the gap correction amount ΔZ can be calculated using the radius r of the machining nozzle 15 and the inclination angle θv of the workpiece W, when there is an angle between the nozzle opening surface 151 and the surface of the workpiece W. The radius r of the machining nozzle 15 and the inclination angle θv of the workpiece W can be determined from the shape of the machining nozzle 15 and the shape of the workpiece W. In other words, the gap correction amount ΔZ can be calculated using the shape of the machining nozzle 15 and the shape of the workpiece W after machining, when there is an angle between the nozzle opening surface 151 and the surface of the workpiece W. The corrected gap amount Zd' between the nozzle opening surface 151 and the surface of the workpiece W at this time is expressed by the following equation (2).

[0054] Zd'=Zd+ΔZ...(2)

[0055] It is also conceivable to input all the corrected gap amounts Zd' corresponding to the inclination angle θv in advance. However, creating a table of corrected gap amounts Zd' corresponding to all inclination angles θv is impractical, and considering implementation in the laser processing device 10, the calculation method shown in Figure 7 is preferable.

[0056] Figure 8 is a diagram illustrating an example of a procedure for correcting laser processing conditions in a vertical processing nozzle used in a laser processing apparatus according to Embodiment 1. Figure 8 shows a method for correcting laser processing conditions using the gap correction amount ΔZ calculated by the method shown in Figure 7, the correction result of the gap amount Zd using the gap correction amount ΔZ, and the method for correcting laser processing conditions. Here, an example of correcting the focal position Zf of the laser beam L is shown. When the nozzle origin On is defined as the point where the nozzle opening surface 151 intersects the central axis Cn of the processing nozzle 15, the focal position Zf of the laser beam L is defined as the position where the laser beam L focuses on the central axis Cn with respect to the nozzle origin On. In other words, the focal position Zf can also be defined as the distance between the nozzle origin On and the focal point of the laser beam L. The nozzle origin On is the origin when generating the processing path. Here again, the processing nozzle 15 is assumed to be a roughly cylindrical vertical processing nozzle. Furthermore, the example given is one in which the B axis, which is the axis of rotation for rotating the workpiece W, is located at the intersection of the surface of the workpiece W and the central axis Cn of the machining nozzle 15.

[0057] State A is a state in which the nozzle opening surface 151 and the surface of the workpiece W are parallel. The gap amount Zd is a value set by the user. Here, the focal position Zf is located on the surface of the workpiece W. In other words, the focal position Zf and the gap amount Zd are set to be equal. By adjusting the focus to be near the surface of the workpiece W, the output density of the laser light L increases. As a result, higher quality processing becomes possible. In this case, there is no contact between the processing nozzle 15 and the workpiece W, and normal vertical processing is possible. Note that the focal position Zf is not limited to being adjusted to the surface of the workpiece W, but can be set to any value such as the center in the thickness direction of the workpiece W. In other words, the gap amount Zd may be set so that the focal position Zf is not on the surface of the workpiece W. In this case, the focal position Zf and the gap amount Zd will be different values.

[0058] State B is the state in which the workpiece W has been rotated clockwise around the B axis by an inclination angle θv from state A. The state is shown in which one end of the nozzle opening surface 151 of the processing nozzle 15 that emits the laser beam L is in contact with the workpiece W. In this state, damage to the processing nozzle 15 or the workpiece W will occur, and the laser processing will be interrupted by the safety function of the laser processing device 10. In this state, the gap amount at the central axis Cn of the processing nozzle 15 is Zd, so the focal position Zf of the laser beam L is on the surface of the workpiece W. That is, the state in which the focal position Zf and the gap amount Zd are equal is maintained.

[0059] State C is a state in which the position of the machining nozzle 15 is corrected in the Z-axis direction from state B, using a gap correction amount ΔZ = r・tanθv calculated by the method shown in Figure 7, in order to avoid contact between the machining nozzle 15 and the workpiece W. The corrected gap amount Zd' is given by equation (2). The corrected gap amount Zd' is the distance in the Z-axis direction between the nozzle origin On of the nozzle opening surface 151 of the machining nozzle 15 and the workpiece W. In this case, unlike state B, the machining nozzle 15 does not come into contact with the workpiece W.

[0060] However, since the focal position Zf is not changed, as the machining nozzle 15 moves in the Z-axis direction, the focal position Zf moves from the surface of the workpiece W in the +Z-axis direction by a gap correction amount ΔZ. In other words, the correction of the position of the machining nozzle 15 causes the focal position Zf of the laser beam L to move away from the surface of the workpiece W. That is, the corrected gap amount Zd' becomes larger than the focal position Zf. This results in a decrease in machining quality when machining inclined holes.

[0061] State D is the state in which the focal position Zf of the laser beam L is adjusted using the gap correction amount ΔZ calculated from state C using the method shown in Figure 7. The corrected focal position Zf' is given by the following equation (3). As shown in equation (3), by correcting the focal position Zf, i.e., the focal length of the laser beam L, to a value equal to the gap correction amount ΔZ, the corrected focal position Zf' will be located at a point at a distance of the corrected gap amount Zd' from the nozzle opening surface 151 on the central axis Cn of the processing nozzle 15. In this example, the corrected focal position Zf' is equal to the corrected gap amount Zd', and the corrected focal position Zf' of the laser beam L becomes the surface of the workpiece W. As a result, even with the corrected gap amount Zd', the corrected focal position Zf' of the laser beam L becomes the desired position before the gap correction, making it possible to suppress a decrease in laser processing quality.

[0062] Zf'=Zd+ΔZ...(3)

[0063] The above procedure makes it possible to avoid contact between the processing nozzle 15 and the workpiece W while suppressing a decrease in laser processing quality when performing inclined processing with a vertical processing nozzle. Here, the focal position relative to the workpiece W during vertical processing such as perpendicular hole processing and the focal position relative to the workpiece W during inclined processing such as inclined hole processing are set to be the same. In the example in Figure 8, the focal position Zf was set to the surface of the workpiece W in both cases. However, in order to obtain good processing conditions, the focal position relative to the workpiece W during vertical processing and inclined processing may be set to different values. In this case, the correction amount α for inclined processing should be set in advance, as shown in the following equation (4).

[0064] Zf'=Zd+ΔZ+α...(4)

[0065] Here, we have shown the correction for the focal position Zf of the laser beam L, but in some cases, the deterioration of laser processing quality can be suppressed by adjusting other laser processing conditions. Other laser processing conditions include at least one of the following: the output of the laser beam L, pulse conditions, and the gas pressure of the assist gas. Pulse conditions include pulse width, pulse period, frequency, and duty cycle. Even when changing these processing conditions, the same procedure as above can be used for correction. That is, processing condition adjustment information showing the relationship between the change in gap amount and the correction amount of the target laser processing condition is obtained in advance. For example, the processing condition adjustment information is a function showing the relationship between the change in gap amount and the correction amount of the laser processing condition. When the gap correction amount ΔZ is calculated, the corresponding correction amount of the target laser processing condition is obtained from the processing condition adjustment information. Then, the target laser processing condition can be corrected according to this correction amount. In this case, the processing condition adjustment information may include a correction amount α to obtain good processing conditions, as shown in equation (4). Also, although the above explanation gave the example of correcting one laser processing condition, multiple laser processing conditions may be corrected.

[0066] In this way, by correcting the laser processing conditions according to the gap correction amount ΔZ, it is possible to correct the deviation in laser processing conditions caused by the correction of the gap amount Zd using the gap correction amount ΔZ. As a result, it becomes possible to perform laser processing with the same laser processing quality as when performing vertical processing with the nozzle opening surface 151 and the surface of the workpiece W being parallel.

[0067] The laser processing apparatus 10 according to Embodiment 1 has the same configuration as that shown in Figure 1. That is, the laser processing apparatus 10 according to Embodiment 1 has a generally cylindrical shape and is equipped with a processing nozzle 15 which is a vertical processing nozzle with a nozzle opening surface 151 perpendicular to the optical axis. Furthermore, in the laser processing apparatus 10 according to Embodiment 1, the processing nozzle 15 is used to correct the gap amount Zd and laser processing conditions as shown in Figure 8, so the function of the processing program generation unit 31 of the control device 30 is different from that of Figure 1. For this reason, the explanation of components that are the same as those in Figure 1 will be omitted, and the configuration of the processing program generation unit 31 will be described.

[0068] The processing program generation unit 31 calculates the position and orientation between the processing nozzle 15 and the workpiece W during laser processing, such as drilling, based on the shape of the processing nozzle 15, workpiece shape data showing the three-dimensional structure of the workpiece W on which an arbitrary processing shape is drawn, and the gap amount Zd between the nozzle opening surface 151 of the processing nozzle 15 and the surface of the workpiece W. If the nozzle opening surface 151 of the processing nozzle 15 and the surface of the workpiece W are at an angle that is not parallel, the processing program generation unit 31 calculates a gap correction amount ΔZ so that the processing nozzle 15 and the workpiece W do not come into contact, and generates a processing program that takes the gap correction amount ΔZ into consideration. Furthermore, the processing program generation unit 31 uses processing condition adjustment information showing the relationship between the change in the gap amount and the correction amount of the laser processing conditions to calculate a correction amount of the laser processing conditions corresponding to the gap correction amount ΔZ, and generates laser processing conditions that take the correction amount into consideration. The processing program generation unit 31 is composed of CAD / CAM.

[0069] Figure 9 is a block diagram showing an example of the configuration of the processing program generation unit of the laser processing apparatus according to Embodiment 1. The processing program generation unit 31 includes a nozzle shape acquisition unit 321, a workpiece shape acquisition unit 322, a processing condition acquisition unit 323, a processing condition storage unit 324, a gap acquisition unit 325, a nozzle information storage unit 326, an inclination angle calculation unit 327, a gap correction amount calculation unit 328, a program generation unit 329, a processing condition adjustment information storage unit 330, a processing condition correction amount calculation unit 331, a processing condition correction unit 332, and a processing information output unit 333.

[0070] The nozzle shape acquisition unit 321 acquires nozzle shape data indicating the shape of the processing nozzle 15 used in the laser processing apparatus 10. Here, the nozzle shape data is information about the external shape of the processing nozzle 15, and also includes information about the size of the processing nozzle 15, such as its radius. In one example, the nozzle shape acquisition unit 321 may acquire nozzle shape data that is directly input by the user to the processing program generation unit 31 via input means such as a keyboard or mouse. In another example, the nozzle shape acquisition unit 321 may acquire nozzle shape data transmitted from another information processing device via a network. In yet another example, the nozzle shape acquisition unit 321 may acquire nozzle shape data stored on a portable storage medium such as a memory card. The nozzle shape data corresponds to the shape data of the processing nozzle 15.

[0071] The workpiece shape acquisition unit 322 acquires workpiece shape data, which is data showing the three-dimensional structure of a workpiece W with processed shapes such as cutting and drilling drawn at arbitrary positions. In one example, the workpiece shape data is a three-dimensional model with the processed shapes drawn. In another example, the workpiece shape acquisition unit 322 may acquire workpiece shape data that is directly input by the user to the processing program generation unit 31 via input means such as a keyboard or mouse. In yet another example, the workpiece shape acquisition unit 322 may acquire workpiece shape data transmitted from another information processing device via a network. In yet another example, the workpiece shape acquisition unit 322 may acquire workpiece shape data stored on a portable storage medium such as a memory card.

[0072] The processing condition acquisition unit 323 acquires processing condition information indicating the content of the laser processing conditions performed by the laser processing apparatus 10, and stores the acquired processing condition information in the processing condition storage unit 324. The processing condition information includes at least one selected from the group of the focal position, output, pulse width, pulse period, frequency, duty cycle, and gas pressure of the assist gas of the laser beam L. The processing condition acquisition unit 323 may also acquire processing condition information that is directly input by the user to the processing program generation unit 31 via input means such as a keyboard or mouse. In another example, the processing condition acquisition unit 323 may acquire processing condition information transmitted from another information processing device via a network. In yet another example, the processing condition acquisition unit 323 may acquire processing condition information stored on a portable storage medium such as a memory card.

[0073] The processing condition storage unit 324 stores processing condition information. As described above, the processing condition information is information that indicates the conditions during laser processing. In other words, the processing condition information includes information that indicates the laser processing conditions.

[0074] The gap acquisition unit 325 acquires the gap amount Zd, which is the distance between the nozzle opening surface 151 of the processing nozzle 15 and the surface of the workpiece W. As described above, the gap amount Zd is the distance between the nozzle opening surface 151 at the central axis Cn of the processing nozzle 15 and the surface of the workpiece W. The gap acquisition unit 325 acquires the set value of the gap amount Zd, which is directly input by the user to the processing program generation unit 31 via input means such as a keyboard or mouse. It is also possible to set the set value of the gap amount Zd to 0. In this case, it is also possible to adjust the gap amount Zd according to the processing content using an offset amount that can be set separately on the laser processing device 10 side.

[0075] The nozzle information storage unit 326 stores nozzle information that associates the shape parameters of the machining nozzle 15 used to calculate the gap correction amount ΔZ, and the correction amount calculation formula used to calculate the gap correction amount ΔZ, with nozzle shape data. In one example, the correction amount calculation formula is a function that expresses the gap correction amount ΔZ using the shape parameters of the machining nozzle 15 and the inclination angle θv, which is the angle between the nozzle opening surface 151 and the surface of the workpiece W. Another example of the shape parameters of the machining nozzle 15 in the case of a vertical machining nozzle is the radius r in the direction perpendicular to the central axis Cn of the machining nozzle 15.

[0076] The inclination angle calculation unit 327 calculates the inclination angle θv between the nozzle opening surface 151, which is the side of the processing nozzle 15 facing the workpiece W, and the surface of the workpiece W at the laser processing position of the workpiece W. Specifically, the inclination angle calculation unit 327 obtains the shape parameters of the processing nozzle 15 corresponding to the nozzle shape data from the nozzle information storage unit 326, and uses the workpiece shape data, nozzle shape data, and the shape parameters of the processing nozzle 15 to calculate the inclination angle θv, which is the angle between the nozzle opening surface 151 and the surface of the workpiece W when the workpiece W is inclined by the processing nozzle 15.

[0077] The gap correction amount calculation unit 328 uses the inclination angle θv and the shape data of the processing nozzle 15 to calculate a gap correction amount ΔZ that corrects the set gap amount Zd between the nozzle opening surface 151 and the surface of the workpiece W. Specifically, the gap correction amount calculation unit 328 obtains a correction amount calculation formula corresponding to the nozzle shape data from the nozzle information storage unit 326, and calculates the gap correction amount ΔZ by substituting the shape parameters of the processing nozzle 15 and the inclination angle θv into the correction amount calculation formula.

[0078] The program generation unit 329 generates processing paths in the areas where laser processing such as cutting and drilling is performed, from work shape data, which is data showing the three-dimensional structure of a workpiece W processed into an arbitrary shape. The program generation unit 329 also generates a processing program, which is a computer program for performing laser processing along the processing path while maintaining a corrected gap between the nozzle opening surface 151 and the surface of the workpiece W using a gap correction amount ΔZ. In one example, templates for processing programs for various types of processing, such as cutting and drilling, are prepared in advance. The template processing program is a program defined so that the processing head 14 moves along the processing path, using items included in the processing condition information as parameters. Here, it is assumed that the processing program references the laser processing conditions from the processing condition information. In other words, the program generation unit 329 generates a processing path for performing laser processing using a three-dimensional model showing the shape of the workpiece W processed into the desired shape, and generates a processing program that includes the processing path. The laser processing conditions used in this processing program are obtained from processing condition information associated with the processing position. Furthermore, the program generation unit 329 corrects the gap amount Zd at the laser processing position in the processing program using a gap correction amount ΔZ. This makes it possible to generate a processing program that performs laser processing while maintaining the distance between the processing nozzle 15 and the surface of the workpiece W with the corrected gap amount Zd' corrected using the gap correction amount ΔZ, even when the gap amount Zd is corrected, without manual intervention.

[0079] The processing condition adjustment information storage unit 330 stores processing condition adjustment information that calculates the correction amount for a predetermined laser processing condition among the laser processing conditions in order to suppress the deterioration of processing quality caused by the correction of the gap amount Zd using the gap correction amount ΔZ. For example, the processing condition adjustment information is information that shows the relationship between the amount of change in the gap amount and the correction amount of the laser processing condition that results in processing quality equal to or better than before the correction of the gap amount Zd when the gap amount Zd is corrected with the gap correction amount ΔZ. The processing condition adjustment information may be a calculation formula or may be data in a table format.

[0080] The processing condition correction amount calculation unit 331 uses the processing condition adjustment information acquired from the processing condition adjustment information storage unit 330 to calculate the correction amount of the laser processing conditions corresponding to the gap correction amount ΔZ calculated by the gap correction amount calculation unit 328.

[0081] The processing condition correction unit 332 generates corrected processing condition information by correcting the laser processing conditions using the correction amount of the laser processing conditions calculated by the processing condition correction amount calculation unit 331. The processing condition correction unit 332 stores the corrected processing condition information in the processing condition storage unit 324. The laser processing conditions to be corrected are predetermined and may be one or more. The processing condition correction unit 332 stores the corrected processing condition information in the processing condition storage unit 324 in association with the processing position. In one example, the processing condition correction unit 332 may generate multiple corrected processing condition information depending on the shape of the processing nozzle 15 and the inclination angle θv between the processing nozzle 15 and the workpiece W.

[0082] The machining information output unit 333 outputs the machining program and corrected machining condition information to the device control unit 33. If there are machining positions where the machining condition information is not corrected, the machining information output unit 333 also outputs the machining condition information to the device control unit 33.

[0083] Figure 10 shows an example of the relationship between input data and output data of the machining program generation unit. The input data to the machining program generation unit 31 is nozzle shape data, workpiece shape data, machining condition information, and the set value of the gap amount Zd between the machining nozzle 15 and the workpiece W. The output data from the machining program generation unit 31 is a machining program that includes the nozzle position considering the gap correction amount ΔZ, and corrected machining condition information according to the gap correction amount ΔZ. If it is necessary to switch laser machining conditions during laser machining, multiple corrected machining condition information may be output.

[0084] The following describes the processing performed by the processing program generation unit 31 when drilling holes using the laser processing device 10. The processing program generation unit 31 generates a processing program for drilling holes based on the workpiece shape data. The processing program generation unit 31 also calculates the gap correction amount ΔZ at each hole position from the nozzle shape data and corrects the gap amount at each hole position in the generated processing program. Furthermore, the processing program generation unit 31 generates and outputs a processing program that switches the laser processing conditions to be used at each hole position according to the gap correction amount ΔZ. The laser processing conditions to be switched may be prepared separately on the laser processing device 10 side, or they may be output by the processing program generation unit 31. In this way, the input data is converted into output data by the processing program generation unit 31.

[0085] In the first embodiment, the device control unit 33 of the laser processing apparatus 10 controls the operation of the laser oscillator 12, the processing gas supply unit 16, and the axis movement control unit 18 according to the processing program generated by the processing program generation unit 31 and the corrected processing condition information. Specifically, the device control unit 33 controls the axis movement control unit 18 so that the value of the corrected gap amount Zd' is the sum of the set gap amount Zd and the gap correction amount ΔZ. The device control unit 33 also controls the laser oscillator 12 and the processing gas supply unit 16 so that they conform to the corrected laser processing conditions indicated in the corrected processing condition information.

[0086] Next, the laser processing method will be described. Figures 11 and 12 are flowcharts showing an example of the processing procedure for the laser processing method according to Embodiment 1. First, the user inputs nozzle shape data indicating the shape of the processing nozzle 15 and workpiece shape data indicating the shape of the workpiece W into the processing program generation unit 31. As a result, the nozzle shape acquisition unit 321 acquires the nozzle shape data (step S31), and the workpiece shape acquisition unit 322 acquires the workpiece shape data (step S32).

[0087] Furthermore, the user sets the laser processing conditions in the processing program generation unit 31. The processing condition acquisition unit 323 then acquires the set laser processing conditions as processing condition information (step S33). The processing condition information is stored in the processing condition storage unit 324. Additionally, the user sets the gap amount Zd between the nozzle opening surface 151 and the surface of the workpiece W in the processing program generation unit 31. The gap acquisition unit 325 then acquires the set value of the gap amount Zd (step S34).

[0088] Next, the inclination angle calculation unit 327 determines the nozzle shape from the input nozzle shape data and obtains the shape parameters of the processing nozzle 15 corresponding to the nozzle shape from the nozzle information in the nozzle information storage unit 326 (step S35). The inclination angle calculation unit 327 also uses the nozzle shape data, the shape parameters of the processing nozzle 15, and the workpiece shape data to calculate the inclination angle θv between the nozzle opening surface 151 and the surface of the workpiece W (step S36). In one example, the inclination angle calculation unit 327 uses the shape data of the processing nozzle 15 and a three-dimensional model showing the shape of the workpiece W processed to the desired shape to calculate the inclination angle θv from the shape of the processing position of the workpiece W. In other words, the inclination angle calculation unit 327 uses a three-dimensional model of the processing nozzle 15 generated from the nozzle shape data and the shape parameters of the processing nozzle 15, and a three-dimensional model of the workpiece W, which is the workpiece shape data, to calculate the inclination angle θv between the nozzle opening surface 151 and the surface of the workpiece W on a computer system. The inclination angle θv is determined according to the angle of the cutting surface in the three-dimensional model of the workpiece W with respect to the surface of the workpiece W. This allows the inclination angle θv to be obtained using data used to generate the machining program. For example, if the workpiece is a hole, the inclination angle θv is calculated using the position, diameter, and angle of the hole obtained from the workpiece shape data. Step S36 corresponds to the inclination angle calculation step in which the control device 30 calculates the inclination angle θv between the nozzle opening surface 151, which is the workpiece W side of the machining nozzle 15, and the surface of the workpiece W at the laser machining position of the workpiece W.

[0089] Subsequently, the gap correction amount calculation unit 328 obtains shape parameters of the processing nozzle 15 corresponding to the nozzle shape obtained from the input nozzle shape data, and a correction amount calculation formula for calculating the gap correction amount ΔZ from the nozzle information of the nozzle information storage unit 326 (step S37). The gap correction amount calculation unit 328 also uses the acquired correction amount calculation formula to calculate the gap correction amount ΔZ corresponding to the inclination angle θv between the nozzle opening surface 151 and the surface of the workpiece W and the shape parameters of the processing nozzle 15 (step S38). Step S38 corresponds to the gap correction amount calculation process in which the control device 30 calculates the gap correction amount ΔZ to correct the set gap amount between the nozzle opening surface 151 and the surface of the workpiece W using the inclination angle θv and the shape data of the processing nozzle 15.

[0090] Next, the program generation unit 329 generates a processing program that includes a processing path for laser processing based on the workpiece shape data (step S39). The program generation unit 329 also corrects the gap amount Zd at the laser processing position in the processing program using a gap correction amount ΔZ (step S40). The corrected gap amount Zd' is obtained by correcting the gap amount Zd with the gap correction amount ΔZ.

[0091] Subsequently, the processing condition correction amount calculation unit 331 calculates the correction amount of the laser processing conditions corresponding to the gap correction amount ΔZ based on the processing condition adjustment information (step S41). Step S41 corresponds to the processing condition correction amount calculation process in which the control device 30 calculates the correction amount of the laser processing conditions corresponding to the gap correction amount ΔZ using processing condition adjustment information that shows the relationship between the change in the gap amount and the correction amount of the laser processing conditions.

[0092] The processing condition correction unit 332 generates corrected processing condition information by correcting the processing condition information in the processing condition storage unit 324 using the calculated correction amount for the laser processing conditions (step S42). Step S42 corresponds to the processing condition correction process in which the control device 30 adjusts the laser processing conditions using the correction amount for the laser processing conditions.

[0093] The processing information output unit 333 then outputs the processing program and the corrected processing condition information to the device control unit 33. The device control unit 33 then reads the processing program and the corrected processing condition information (step S43).

[0094] When processing multiple locations on the workpiece W, the gap correction amount ΔZ and the correction amount for the laser processing conditions are calculated for each location. Then, the gap amount Zd is corrected in the laser processing section of the processing program for each location, and corrected processing condition information is generated for each location.

[0095] Subsequently, similar to the processes from step S16 to step S17 in Figure 4, the user prepares for the machining process and starts executing the machining program (steps S44 to S45).

[0096] Next, the device control unit 33 controls the position and orientation of the processing head 14 and table 11 according to the processing program (step S46). The device control unit 33 also switches the laser processing conditions to corrected processing condition information, which is the laser processing condition corresponding to the gap correction amount ΔZ (step S47). After that, piercing is performed, followed by trepanning, similar to the process from steps S19 to S20 in Figure 5 (steps S48 to S49). Although drilling is shown as an example here, other processing methods are performed using the same procedure. Steps S46 to S49 correspond to the device control process in which the control device 30 controls the axis movement control unit 18 so that the corrected gap amount is the sum of the set gap amount and the gap correction amount ΔZ.

[0097] Subsequently, the device control unit 33 determines whether all processing has been performed (step S50). If not all processing has been performed (if the answer is No in step S50), the processes from steps S46 to S49 are repeated. If all processing has been performed (if the answer is Yes in step S50), the execution of the processing program ends (step S51), and the laser processing method ends.

[0098] As described above, in Embodiment 1, in a laser processing apparatus 10 having a vertical processing nozzle as the processing nozzle 15, the processing program generation unit 31 performs the following: recognition of the shape of the processing nozzle 15, calculation of a gap correction amount ΔZ for the gap between the processing nozzle 15 and the workpiece W to avoid contact, generation of a processing program including a processing path using the calculated gap correction amount ΔZ, and generation of corrected processing condition information. By performing laser processing with a processing program based on the processing path generated considering the gap correction amount ΔZ and the corrected processing condition information, it becomes possible to perform laser processing of higher quality than conventional methods while avoiding contact between the processing nozzle 15 and the workpiece W. For example, even when the position of the processing nozzle 15 is changed to avoid contact during inclined processing, from a state where the focal position Zf of the laser beam L during vertical processing is set on the surface of the workpiece W, laser processing can be performed without the focal position Zf' of the laser beam L shifting from the surface of the workpiece W.

[0099] Embodiment 2. Figure 6, state A of Embodiment 1, shows a case where the processing nozzle 15 can be installed substantially perpendicular to the surface of the workpiece W. In other words, it shows a case where the central axis Cn of the processing nozzle 15 can be installed almost perpendicular to the surface of the workpiece W. Since the nozzle opening surface 151 of the processing nozzle 15 is perpendicular to the central axis Cn, the assist gas is blown out perpendicular to the nozzle opening surface 151, and the assist gas is also blown perpendicularly onto the surface of the workpiece W. In such a case, when performing laser processing, sufficient pressure can be applied to the melting area by the laser beam L by the assist gas from the processing nozzle 15. As a result, the melting area can be appropriately discharged to the back side of the workpiece W.

[0100] On the other hand, state C in Figure 6 shows a case where the processing nozzle 15 is installed at an angle to the surface of the workpiece W. In this case, the assist gas from the processing nozzle 15 is blown at an angle that is not perpendicular to the surface of the workpiece W. Therefore, if the inclination angle θv becomes large, the flow of assist gas from the processing nozzle 15 is deflected at the surface of the workpiece W, and sufficient pressure cannot be applied to the melting area by the laser beam L. Note that the inclination angle θv is the angle between the nozzle opening surface 151 and the surface of the workpiece W, but it is also the angle of the central axis Cn of the processing nozzle 15 with respect to the normal to the surface of the workpiece W.

[0101] To solve these problems, Embodiment 2 uses a tilting nozzle, which is a processing nozzle 15 inclined with respect to the central axis Cn, where the nozzle opening surface 151 is tilted. Figure 13 is a diagram showing an example of the configuration of a tilting nozzle used in a laser processing apparatus according to Embodiment 2. In Embodiment 2, a processing nozzle 15a is used instead of the processing nozzle 15 of Embodiment 1. The processing nozzle 15a is a tilting nozzle.

[0102] The optical axis of the processing head 14 is assumed to coincide with the central axis Cn of the processing nozzle 15a. As shown in Figure 13, the processing nozzle 15a is a nozzle having a nozzle opening surface 151 that is inclined at an angle not perpendicular to the central axis Cn. Specifically, the processing nozzle 15a has a first cylindrical portion 152 whose diameter is constant in the direction perpendicular to the central axis Cn, and a second cylindrical portion 153 provided at the end of the first cylindrical portion 152 on the side from which the laser beam L is emitted, and having a nozzle opening surface 151 that is inclined at an angle not perpendicular to the central axis Cn. The nozzle opening surface 151 of the second cylindrical portion 153 is inclined at an angle θc with respect to the plane perpendicular to the central axis Cn of the processing nozzle 15a. This angle θc is called the nozzle inclination angle θc. The diameter of the second cylindrical portion 153 decreases along the nozzle opening surface 151. In such a processing nozzle 15a, the nozzle opening surface 151 can be made nearly parallel to the surface of the workpiece W when the workpiece W is rotated around the B axis and tilted. This allows sufficient pressure to be applied to the melting area by the laser beam L using assist gas, thereby suppressing the deterioration of laser processing quality in tilted processing.

[0103] The laser processing apparatus 10 according to Embodiment 2 has the same configuration as that in Embodiment 1, except for the processing nozzle 15a. In other words, in Embodiment 1, the processing nozzle 15 was a nozzle for vertical processing, but in Embodiment 2, the processing nozzle 15a is a nozzle for inclined processing.

[0104] If the proportion of angled machining is greater than perpendicular machining in the shape to be machined of the workpiece W, or if the machining quality of angled machining cannot be sufficiently obtained with a normal vertical machining nozzle, then it is advisable to use an angled machining nozzle. Here, the nozzle inclination angle θc of the angled machining nozzle used should ideally be the same as the inclination angle θv of the workpiece W, but even if they are different, as described above, the effect of improving machining quality can be obtained if sufficient pressure is applied.

[0105] Embodiment 2 shows an example of shape parameters and a correction amount calculation formula used to calculate the gap correction amount ΔZ for avoiding contact between the processing nozzle 15a and the workpiece W when using the above-described inclined processing nozzle. Embodiment 2 also shows an example of correction of laser processing conditions in conjunction with the correction of the gap amount Zd.

[0106] Figure 14 is a diagram illustrating the procedure for calculating the gap correction amount and the nozzle position correction procedure for the inclined machining nozzle used in the laser processing apparatus according to Embodiment 2. Here, the inclined machining nozzle, which is the processing nozzle 15a, has a shape in which a generally cylindrical processing nozzle is beveled at an arbitrary position, and the surface of the workpiece W is assumed to be smooth. Furthermore, the rotation axis B is assumed to be at the intersection of the surface of the workpiece W and the central axis Cn of the processing nozzle 15a. In Embodiment 2, a tracking sensor is not used.

[0107] The inclined machining nozzle is a machining nozzle 15a that is suitably used when forming a cut surface having an inclination angle that is not perpendicular to the surface of the workpiece W. In one example, the nozzle opening surface 151 of the inclined machining nozzle is inclined at a nozzle inclination angle θc that is not perpendicular to the central axis Cn of the machining nozzle 15a. As a result, the machining nozzle 15a has a configuration in which the assist gas is blown out at an angle with respect to the central axis Cn.

[0108] In the following description, the nozzle origin On used for generating the machining path is defined as the position on a virtual plane perpendicular to the central axis Cn of the machining nozzle 15a passing through the boundary between the first cylindrical portion 152 and the second cylindrical portion 153, where the central axis Cn passes. Furthermore, the gap amount Zd between the machining nozzle 15a and the workpiece W is defined as the distance between the nozzle opening surface 151 at the central axis Cn of the inclined machining nozzle and the surface of the workpiece W.

[0109] State A is a state in which the nozzle opening surface 151 and the surface of the workpiece W are parallel. The surface of the workpiece W, which is inclined at an inclination angle θv, and the nozzle opening surface 151 of the machining nozzle 15a are parallel. When performing inclined machining, machining is performed in this state. The amount of gap between the machining nozzle 15a and the surface of the workpiece W is controlled according to the gap setting value set by the user. Since the nozzle opening surface 151 and the surface of the workpiece W are parallel, the gap amount Zd is the same at any position on the nozzle opening surface 151.

[0110] In the machining program, the gap amount between the nozzle origin On at the central axis Cn and the surface of the workpiece W is taken into consideration. Therefore, a correction of the gap amount Zd due to the nozzle shape of the machining nozzle 15a is taken into consideration. The correction amount Zn due to the nozzle shape is expressed by the following equation (5), using the radius r of the machining nozzle 15a and the nozzle inclination angle θc of the nozzle opening surface 151 of the machining nozzle 15a. The nozzle inclination angle θc is the angle of the nozzle opening surface 151 with respect to a virtual plane perpendicular to the central axis Cn of the boundary between the first cylindrical portion 152 and the second cylindrical portion 153. This virtual plane corresponds to the XY plane.

[0111] Zn=r・tanθc...(5)

[0112] In state A, the gap between the nozzle origin On and the surface of the workpiece W is controlled to be Zd + Zn. Furthermore, it is possible to bring the nozzle opening surface 151 and the surface of the workpiece W into close proximity over a wide area, allowing the assist gas to be applied to the melting area by the laser beam L without diverting to the surface of the workpiece W. As a result, stable processing becomes possible. Note that when laser processing is performed in this state, no correction is made to the gap amount Zd + Zn.

[0113] State B is a state in which there is an angle between the nozzle opening surface 151 and the surface of the workpiece W, and the processing nozzle 15a is in contact with the surface of the workpiece W. Specifically, the inclination angle θv of the surface of the workpiece W is 0 degrees, and the tip of the processing nozzle 15a is in contact with the surface of the workpiece W. The processing nozzle 15a and the workpiece W come into contact depending on the relationship between the radius r of the processing nozzle 15a, the gap amount Zd, the inclination angle θv of the workpiece W, and the nozzle inclination angle θc of the processing nozzle 15a. This contact can cause damage to the laser processing device 10 or the workpiece W. In this example, correction is made by the nozzle shape, but the gap amount is not corrected by the rotation of the workpiece W.

[0114] State C is a state in which there is an angle between the nozzle opening surface 151 and the surface of the workpiece W, and the gap amount is corrected. In state C, the gap correction amount ΔZ is calculated according to the following equation (6) using the radius r of the processing nozzle 15a, the gap amount Zd, the inclination angle θv of the workpiece W, and the nozzle inclination angle θc of the processing nozzle 15a. Then, by using this gap correction amount ΔZ to move the nozzle position in the direction of the +Z axis, that is, away from the workpiece W, contact between the processing nozzle 15a and the workpiece W is avoided. By avoiding contact between the processing nozzle 15a and the workpiece W, stable laser processing becomes possible.

[0115] ΔZ=r・|tanθc−tanθv| ...(6)

[0116] As described above, without using a tracking sensor, the gap correction amount ΔZ for the gap amount Zd + Zn between the nozzle origin On and the surface of the workpiece W when machining a workpiece W at an inclination angle θv using an inclined machining nozzle can be calculated using the radius r of the machining nozzle 15a, the gap amount Zd, the inclination angle θv of the workpiece W, and the nozzle inclination angle θc of the machining nozzle 15a. The radius r and nozzle inclination angle θc of the machining nozzle 15a and the inclination angle θv of the workpiece W can be determined from the shape of the machining nozzle 15a and the shape of the workpiece W. In other words, the gap correction amount ΔZ for the gap amount Zd + Zn between the nozzle origin On and the surface of the workpiece W when machining a workpiece W at an inclination angle θv using an inclined machining nozzle can be calculated using the shape of the machining nozzle 15a, the shape of the workpiece W after machining, and the gap amount Zd.

[0117] Furthermore, although this explanation uses a nozzle for inclined machining with a nozzle inclination angle θc as an example, when the nozzle inclination angle θc is 0 degrees, it becomes a vertical machining nozzle as described in Embodiment 1. In this case, the correction amount Zn due to the nozzle shape becomes 0 from equation (5). Also, the gap correction amount ΔZ becomes r・tanθv from equation (6), which is the same as equation (1). In other words, the gap correction amount calculation unit 328 can calculate the gap correction amount ΔZ using the radius r in the direction perpendicular to the central axis Cn of the machining nozzles 15, 15a, the nozzle inclination angle θc, and the inclination angle θv of the workpiece W. As a result, the corrected gap amount Zd' becomes Zd + ΔZ, which is the same form as that obtained in Embodiment 1. Thus, the corrected gap amount Zd' in Embodiment 2 can be expressed as Zd + Zn + ΔZ by using the nozzle inclination angle θc, and can be used for both vertical machining nozzles and inclined machining nozzles.

[0118] It is also conceivable to input in advance all the gap amounts Zd + Zn + ΔZ between the nozzle origin On and the surface of the workpiece W, corresponding to the workpiece W tilt angle θv and nozzle tilt angle θc. However, creating a table of gap amounts corresponding to all nozzle tilt angles θc for all workpiece W tilt angles θv is impractical, and considering implementation in the laser processing apparatus 10, the calculation method shown in Figure 14 is preferable.

[0119] Figure 15 is a diagram illustrating an example of a procedure for correcting laser processing conditions in a tilting nozzle used in a laser processing apparatus according to Embodiment 2. Figure 15 shows a method for correcting laser processing conditions using the correction amount Zn and gap correction amount ΔZ calculated by the nozzle shape method shown in Figure 14, and the position correction result using the correction amount Zn and gap correction amount ΔZ. Here, an example of correcting the focal position Zf of the laser beam L among the laser processing conditions is shown. Here again, the tilting nozzle, which is the processing nozzle 15a, is assumed to be a shape that is roughly cylindrical and cut at an angle at an arbitrary position. The correction of the gap amount Zd is performed by moving the processing nozzle 15a in the Z-axis direction. Furthermore, an example is given in which the B axis, which is the rotation axis that rotates the workpiece W, is at the intersection of the central axis Cn of the processing nozzle 15a and the surface of the workpiece W. The workpiece W rotates clockwise or counterclockwise around the B axis. Furthermore, here too, the nozzle origin On used for generating the machining path is defined as the position through which the central axis Cn of the machining nozzle 15a passes on a virtual plane perpendicular to the central axis Cn of the machining nozzle 15a passing through the boundary between the first cylindrical portion 152 and the second cylindrical portion 153.

[0120] State A is the state in which the nozzle opening surface 151 and the surface of the workpiece W are parallel. The gap amount Zd is a value set by the user. In Figure 15, since the nozzle opening surface 151 and the surface of the workpiece W are parallel, the gap amount Zd is the same at any position on the nozzle opening surface 151. If the nozzle opening surface 151 and the surface of the workpiece W are not parallel, the gap amount Zd is the distance in the Z-axis direction between the nozzle opening surface 151 and the surface of the workpiece W on the central axis Cn of the nozzle passing through the nozzle origin On. Note that the gap amount between the nozzle origin On and the surface of the workpiece W along the central axis Cn is Zd + Zn, which further takes into account the correction amount Zn due to the nozzle shape shown in equation (5).

[0121] Here, the position on the central axis Cn of the processing nozzle 15a, moved by a distance of gap amount Zd from the nozzle opening surface 151, is set to be equal to the focal position Zf of the laser beam L. In other words, the gap amount Zd is set so that the focal position Zf of the laser beam L is on the surface of the workpiece W. By adjusting the focal position Zf to be near the surface of the workpiece W, the output density of the laser beam L can be increased, enabling higher quality processing. In this case, there is no contact between the processing nozzle 15a and the workpiece W, and normal inclined machining is possible. Note that the focal position Zf is not limited to being adjusted to the surface of the workpiece W, but can be set to any value, such as the center in the thickness direction of the workpiece W. In other words, the gap amount Zd may be set so that the focal position Zf is not on the surface of the workpiece W.

[0122] State B is the state in which the workpiece W is rotated counterclockwise by an inclination angle θv from state A. This causes the processing nozzle 15a and the workpiece W to come into contact. In this state, damage to the processing nozzle 15a or the workpiece W occurs, and the laser processing is interrupted by the safety function of the laser processing device 10. In this state, the gap amount at the central axis Cn of the processing nozzle 15a is Zd, so the focal position Zf of the laser beam L is located on the surface of the workpiece W.

[0123] State C is a state in which, from state B, the nozzle position is corrected in the Z-axis direction using the method shown in Figure 14, i.e., the gap correction amount ΔZ calculated by equation (6), in order to avoid contact between the inclined machining nozzle and the workpiece W. The corrected gap amount Zd' between the corrected nozzle origin On and the surface of the workpiece W is given by the following equation (7). The corrected gap amount Zd' is the distance between the nozzle origin On and the workpiece W at the central axis Cn of the machining nozzle 15a. Therefore, the corrected gap amount Zd' also includes the correction amount Zn due to the shape of the inclined machining nozzle shown in equation (5). In this case, unlike state B, the inclined machining nozzle does not come into contact with the workpiece W.

[0124] Zd'=Zd+Zn+ΔZ...(7)

[0125] However, since the focal position Zf is not changed, as the machining nozzle 15a moves in the Z-axis direction, the focal position Zf moves from the surface of the workpiece W in the +Z-axis direction by a gap correction amount ΔZ. In other words, on the central axis Cn of the machining nozzle 15a, the position moved by a distance of gap amount Zd' from the nozzle origin On is on the surface of the workpiece W, but the focal position Zf of the laser beam L moves away from the surface of the workpiece W. This results in a decrease in laser machining quality when performing vertical hole machining in state C.

[0126] State D is the state in which the focal position Zf of the laser beam L has been adjusted from state C using the method shown in Figure 14, that is, using the gap correction amount ΔZ calculated by equation (6). The corrected focal position Zf' is given by the following equation (8). However, in equation (8), the reference point for the focal position Zf and the corrected focal position Zf' is the intersection of the central axis Cn and the nozzle opening surface 151. Therefore, the difference between the position of the nozzle origin On on the central axis Cn and the position of the nozzle opening surface 151 is corrected using a correction amount Zn due to the nozzle shape. As shown in equation (8), by correcting the focal position Zf', i.e., the focal length of the laser beam L, the focal position Zf' will be located at a point at a distance of the corrected gap amount Zd' from the nozzle origin On on the central axis Cn of the processing nozzle 15a. In this example, the corrected focal position Zf' of the laser beam L is the surface of the workpiece W.

[0127] Zf'=Zd+Zn+ΔZ...(8)

[0128] The above procedure makes it possible to avoid contact between the processing nozzle 15a and the workpiece W while suppressing a decrease in laser processing quality when performing vertical processing with the processing nozzle 15a. Here, the focal position relative to the workpiece W is the same for vertical processing such as perpendicular hole processing and for inclined processing such as inclined hole processing. In the example in Figure 15, the focal position Zf is set to the surface of the workpiece W in both cases. However, in order to obtain good processing conditions, the focal position relative to the workpiece W may be set to different values ​​for vertical processing and inclined processing. In this case, the correction amount β for vertical processing should be set in advance, as shown in the following equation (9).

[0129] Zf'=Zd+Zn+ΔZ+β...(9)

[0130] Here, we have shown the correction for the focal position Zf of the laser beam L, but in some cases, the deterioration of laser processing quality can be suppressed by adjusting other laser processing conditions. Other laser processing conditions include the output of the laser beam L, pulse conditions, and gas pressure. Pulse conditions include pulse width, pulse period, frequency, and duty cycle. Even when changing these processing conditions, the same procedure as above can be used for correction. That is, processing condition adjustment information showing the relationship between the change in gap amount and the correction amount of the target laser processing condition is obtained in advance. For example, the processing condition adjustment information is a function showing the relationship between the change in gap amount and the correction amount of the laser processing condition. When the gap correction amount ΔZ is calculated, the corresponding correction amount of the target laser processing condition is obtained from the processing condition adjustment information. Then, the target laser processing condition can be corrected according to this correction amount. In this case, the processing condition adjustment information may include a correction amount β to obtain good processing conditions, as shown in equation (9). Also, although the above explanation gave the example of correcting one laser processing condition, multiple laser processing conditions may be changed.

[0131] The configuration of the laser processing apparatus 10 according to Embodiment 2 is the same as that described in Figure 9 of Embodiment 1. However, as described above, in Embodiment 2, the processing nozzle 15a is a nozzle for inclined processing and has a different shape from the nozzle for vertical processing in Embodiment 1. For this reason, the shape parameters of the processing nozzle 15a in the nozzle information of the nozzle information storage unit 326 include the radius r of the first cylindrical portion 152 and the nozzle inclination angle θc of the nozzle opening surface 151. The gap correction amount calculation unit 328 calculates the gap correction amount ΔZ using the radius r in the direction perpendicular to the central axis Cn of the processing nozzle 15a, the nozzle inclination angle θc which is the angle of the nozzle opening surface 151 with respect to the XY plane, and the inclination angle θv between the workpiece W and the nozzle opening surface 151. In other words, the difference from Embodiment 1 is that equations (5) to (6) are used in the calculation of the gap correction amount ΔZ by the gap correction amount calculation unit 328. This makes it possible to calculate the gap correction amount ΔZ that prevents contact between the workpiece W and the machining nozzle 15a, according to the inclination angle θv of the workpiece W surface and the nozzle inclination angle θc, without using a tracking sensor.

[0132] Furthermore, the laser processing method according to Embodiment 2 is the same as that described in Figures 11 and 12 of Embodiment 1. However, in step S38, the gap correction amount calculation unit 328 uses the radius r in the direction perpendicular to the central axis Cn of the processing nozzle 15a and the nozzle inclination angle θc, which is the angle of the nozzle opening surface 151 with respect to the XY plane, as shape parameters of the processing nozzle 15a, and calculates the gap correction amount ΔZ from equation (6). Also, in step S40, the program generation unit 329 corrects the gap amount Zd using equation (7) and calculates the corrected gap amount Zd'.

[0133] In Embodiment 2, the laser processing apparatus 10 having a nozzle for inclined processing performs the following in the processing program generation unit 31: recognition of the shape of the processing nozzle 15a, calculation of the gap correction amount ΔZ for the gap between the processing nozzle 15a and the workpiece W to avoid contact, generation of a processing program including a processing path using the gap correction amount ΔZ, and generation of corrected processing condition information. By performing laser processing with a processing program based on the processing path generated considering the gap correction amount ΔZ and the corrected processing condition information, it becomes possible to perform laser processing of higher quality than conventional methods, even during inclined processing, while avoiding contact between the processing nozzle 15a and the workpiece W.

[0134] Embodiment 3. The laser processing apparatus 10 of Embodiment 3 has the same configuration as those in Embodiments 1 and 2, but performs laser processing by manually or automatically switching between a plurality of processing nozzles 15, 15a with different shapes. In one example, the processing shape of the workpiece W to be processed may include both perpendicular holes and inclined holes, and the inclined holes may include processing holes with various inclination angles. In this case, good processing quality can be obtained when a perpendicular hole is laser processed using a normal vertical processing nozzle, but the processing quality may decrease when an inclined hole is laser processed using a vertical processing nozzle. Conversely, good processing quality can be obtained when an inclined hole is laser processed using an inclined processing nozzle, but the processing quality may decrease when a perpendicular hole is laser processed using an inclined processing nozzle. Therefore, Embodiment 3 describes a laser processing apparatus 10 and a laser processing method that can change the nozzle according to the inclination angle of the processing hole. It is desirable to prepare inclined processing nozzles that correspond to all inclination angles θv, but this is not practical. For this reason, here we will describe the case in which two nozzles, a vertical processing nozzle and an inclined processing nozzle, are switched. However, the number of machining nozzles 15, 15a to be switched is not limited to two. If the number of machining nozzles 15, 15a is three or more, multiple inclined machining nozzles with different nozzle inclination angles θc are provided.

[0135] Figure 16 shows an example of laser processing conditions when using a vertical processing nozzle and an inclined processing nozzle used in a laser processing apparatus according to Embodiment 3. Here, the laser processing apparatus 10 is assumed to have two types of processing nozzles 15 and 15a: a processing nozzle 15 which is a vertical processing nozzle having a nozzle opening surface 151 with a nozzle inclination angle of 0 degrees, and a processing nozzle 15a which is an inclined processing nozzle having a nozzle opening surface 151 with a nozzle inclination angle of θc degrees. The radius of the vertical processing nozzle in the direction perpendicular to the central axis Cn is r. The radius of the first cylindrical portion 152 of the inclined processing nozzle in the direction perpendicular to the central axis Cn is also r.

[0136] Figure 16 defines the types of processing nozzles 15 and 15a used, depending on the inclination angle θv of the surface of the workpiece W with respect to the XY plane, centered on the B axis, which is an axis parallel to the Y-axis. When the inclination angle θv of the surface of the workpiece W is 0 ≤ θv < θc / 2, a vertical processing nozzle is used, as shown in states A and B. In state B, as explained in Embodiment 1, the gap amount between the processing nozzle 15 and the surface of the workpiece W is corrected using the gap correction amount ΔZ shown in equation (1) so that the gap amount Zd' shown in equation (2) is obtained. Furthermore, the correction amount of the laser processing conditions corresponding to the gap correction amount ΔZ is calculated from a function showing the relationship between the change in the gap amount Zd and the correction amount of the laser processing conditions to be corrected, and the target laser processing conditions are corrected using this correction amount of the laser processing conditions.

[0137] When the inclination angle θv of the surface of the workpiece W is θc / 2 ≤ θv ≤ θc, an inclined machining nozzle is used as shown in states C and D. In states C and D, as explained in Embodiment 2, the gap between the machining nozzle 15a and the surface of the workpiece W is corrected using the gap correction amount ΔZ shown in equation (6) so that the gap amount Zd' shown in equation (7) is obtained. Furthermore, the correction amount for the laser machining conditions corresponding to the gap correction amount ΔZ is calculated from a function showing the relationship between the change in the gap amount Zd and the correction amount of the laser machining conditions to be corrected, and the target laser machining conditions are corrected using this correction amount for the laser machining conditions.

[0138] Note that the example shown in Figure 16 is just one example, and the angle at which the processing nozzles 15 and 15a are switched does not necessarily have to be θc / 2. In the case of drilling, the angle at which the processing nozzles 15 and 15a are switched can be changed as long as it is an angle that can obtain the necessary laser processing quality for both perpendicular and inclined hole processing. In this example, a nozzle for vertical processing and a nozzle for inclined processing were shown, but depending on the processing content, multiple processing nozzles 15, including processing nozzles 15 with shapes other than those shown in these examples, may be used. In that case, the correction amount is calculated using a calculation formula appropriate for the processing nozzle 15 being used.

[0139] The configuration of the laser processing apparatus 10 according to Embodiment 3 is the same as that described in Figure 9 of Embodiment 1. However, as described above, in Embodiment 3, the laser processing apparatus 10 has a plurality of processing nozzles 15, 15a. For this reason, the nozzle information storage unit 326 stores nozzle information for the plurality of processing nozzles 15, 15a provided in the laser processing apparatus 10. In the example of Figure 16, the nozzle information storage unit 326 stores nozzle information for the vertical processing nozzle, which associates the shape parameters of the processing nozzle 15 and the correction amount calculation formula used to calculate the gap correction amount ΔZ with the nozzle shape of the vertical processing nozzle, and nozzle information for the inclined processing nozzle, which associates the shape parameters of the processing nozzle 15a, including the nozzle inclination angle θc, and the correction amount calculation formula used to calculate the gap correction amount ΔZ with the nozzle shape of the inclined processing nozzle. The nozzle information also includes nozzle selection conditions, which are the conditions under which each processing nozzle 15, 15a is selected. An example of a nozzle selection condition is the range of the inclination angle θv of the surface of the workpiece W in which each machining nozzle 15, 15a is selected. The range of the inclination angle θv of the surface of the workpiece W may be defined using the nozzle inclination angle θc, as shown in the example in Figure 16.

[0140] Furthermore, the laser processing method according to Embodiment 3 is the same as that described in Figures 11 and 12 of Embodiment 1 and the one described in Embodiment 2.

[0141] Furthermore, the gap correction amount calculation unit 328 and the machining condition correction amount calculation unit 331 refer to the nozzle selection conditions of the nozzle information and select machining nozzles 15, 15a that can be used with the inclination angle θv of the surface of the workpiece W calculated by the inclination angle calculation unit 327, and obtain nozzle information for the selected machining nozzles 15, 15a from the nozzle information storage unit 326.

[0142] Here, we will explain how to generate a machining program that changes the machining nozzles 15 and 15a. When machining holes with various inclination angles are mixed, for example, a machining program can be generated in which machining positions that can be machined with a vertical machining nozzle are machined first, a machining nozzle change procedure is included to change from a vertical machining nozzle to an inclined machining nozzle, and the remaining machining positions are machined with an inclined machining nozzle.

[0143] In the processing nozzle changing procedure, if the processing nozzles 15 and 15a are to be changed manually, one possible method is to stop the processing program once, provide a waiting time for the operator to change the processing nozzles 15 and 15a, and restart the processing program. Alternatively, if the laser processing device 10 is equipped with a mechanism for automatically changing the processing nozzles 15 and 15a, the processing program can be designed to move the processing head 14 to the position where the processing nozzles 15 and 15a are to be changed, issue a command to the laser processing device 10 to automatically change the processing nozzles 15 and 15a, and then resume processing. However, the embodiment 3 is not limited by such a processing nozzle changing procedure. Furthermore, if changing the processing nozzles 15 and 15a multiple times is more efficient in terms of processing time, etc., than processing all positions that can be processed with a single processing nozzle 15 and 15a first, the processing nozzle changing procedure may include changing the processing nozzles 15 and 15a multiple times.

[0144] By using the above method, it becomes possible to perform high-quality and stable laser processing, such as drilling holes at various inclination angles, using a minimum number of processing nozzles 15, 15a, while avoiding contact between the processing nozzles 15, 15a and the workpiece W.

[0145] The processing nozzle change procedure shown above is just one example, and may be modified depending on whether or not contact occurs due to the workpiece W's inclination angle θv and the processing quality. While it is conceivable to input all gap amounts corresponding to the nozzle inclination angle θc in advance, creating a table of gap amounts corresponding to all nozzle inclination angles θc is impractical. Furthermore, while it is conceivable to prepare inclined processing nozzles with corresponding nozzle inclination angles θc for every processing nozzle 15, 15a and workpiece W inclination angle θv, this is impractical in terms of workability and profitability. Considering implementation in the laser processing apparatus 10, it is desirable to calculate the gap correction amount ΔZ and the laser processing condition correction amount using the method illustrated in Figure 16.

[0146] In Embodiment 3, in a laser processing apparatus 10 that processes by switching between multiple processing nozzles 15, 15a of different shapes, the processing program generation unit 31 recognizes the shapes of the processing nozzles 15, 15a, calculates the gap correction amount ΔZ for the gap between the processing nozzles 15, 15a and the workpiece W to avoid contact, generates a processing program including a processing path using the gap correction amount ΔZ, and generates corrected processing condition information. By performing laser processing with a processing program based on the processing path generated considering the gap correction amount ΔZ and the corrected processing condition information, it becomes possible to perform laser processing of higher quality than conventional methods while avoiding contact between the processing nozzles 15, 15a and the workpiece W. Furthermore, when processing in the order of the processing holes that appear in the shortest processing path, the type of processing hole to be processed may differ from the previous processing hole. In this case, it is necessary to switch the processing nozzles 15, 15a each time. However, by creating a processing path that drills holes of the same type together, the total time required to switch the processing nozzles 15, 15a can be shortened.

[0147] Furthermore, the laser processing apparatus 10 includes at least one of a vertical processing nozzle having a nozzle opening surface 151 perpendicular to the central axis Cn of the processing nozzle 15, and an inclined processing nozzle having a nozzle opening surface 151 that is inclined at an angle not perpendicular to the central axis Cn of the processing nozzle 15a. The gap correction amount calculation unit 328 and the processing condition correction amount calculation unit 331 select the processing nozzles 15, 15a to be used for laser processing according to the relationship between the inclination angle θv between the surface of the workpiece W and the nozzle opening surface 151 of the processing nozzles 15, 15a and the nozzle inclination angle θc of the inclined processing nozzle. This makes it possible to select the type of processing nozzle 15, 15a that can maintain the desired laser processing quality while avoiding contact between the processing nozzles 15, 15a and the workpiece W during laser processing of the workpiece W, whether vertical or inclined processing.

[0148] Furthermore, the gap correction amount calculation unit 328 calculates the gap correction amount ΔZ by referring to nozzle information that associates shape parameters with a correction amount calculation formula for calculating the gap correction amount ΔZ for each shape of the processing nozzles 15, 15a. This makes it possible to calculate an appropriate gap correction amount ΔZ according to the inclination angle θv for each shape of the processing nozzles 15, 15a, even when there are multiple types of processing nozzles 15, 15a. As a result, it becomes possible to perform laser processing with the desired laser processing quality while avoiding contact between the processing nozzles 15, 15a and the workpiece W.

[0149] The control device 30 in the laser processing apparatus 10 according to Embodiments 1 to 3 can be implemented by an information processing device, for example. The hardware configuration when the control device 30 is implemented by a computer system which is an information processing device will be described below. The computer system functions as the control device 30 when a program, which is a computer program describing the processing in the control device 30, is executed on the computer system. Figure 17 is a block diagram showing an example of the configuration of a computer system that implements the control device of the laser processing apparatus according to Embodiments 1 to 3. As shown in Figure 17, this computer system includes a control unit 901, an input unit 902, a storage unit 903, a display unit 904, a communication unit 905, and an output unit 906, which are connected via a system bus 907.

[0150] In Figure 17, the control unit 901 is, in one example, a processor such as a CPU (Central Processing Unit), and executes a program that describes the processing in the control device 30 of Embodiments 1 to 3. The input unit 902 is, in one example, composed of a keyboard, mouse, etc., and is used by the user of the computer system to input various information. The storage unit 903 includes various types of memory such as RAM (Random Access Memory) and ROM (Read Only Memory), and storage devices such as a hard disk, and stores the program that the control unit 901 should execute, necessary data obtained in the process of processing, etc. The storage unit 903 is also used as a temporary storage area for the program. The display unit 904 is composed of a display, liquid crystal display panel, etc., and displays various screens to the user of the computer system. In one example, the input unit 902 and the display unit 904 may be configured as a touch panel in which the input unit 902 and the display unit 904 are integrally formed. The communication unit 905 is a receiver and transmitter that perform communication processing. The output unit 906 is a printer, speaker, etc. Note that Figure 17 is just one example, and the configuration of the computer system is not limited to the example shown in Figure 17.

[0151] Here, we will describe an example of the operation of a computer system until a program becomes executable. In a computer system with the above configuration, for example, a program is installed in the storage unit 903 from a CD-ROM or DVD-ROM set in a CD (Compact Disc)-ROM drive or DVD (Digital Versatile Disc)-ROM drive (not shown). When the program is executed, the program read from the storage unit 903 is stored in the main memory area of ​​the storage unit 903. In this state, the control unit 901 performs processing as the control device 30 of embodiments 1 to 3 according to the program stored in the storage unit 903.

[0152] In the above description, a program describing the processing in the control device 30 is provided using a CD-ROM or DVD-ROM as the recording medium. However, the system is not limited to this, and depending on the configuration of the computer system, the capacity of the program to be provided, a program provided via a transmission medium such as the Internet via the communication unit 905 may also be used.

[0153] The device control unit 33, nozzle shape acquisition unit 321, workpiece shape acquisition unit 322, machining condition acquisition unit 323, gap acquisition unit 325, inclination angle calculation unit 327, gap correction amount calculation unit 328, program generation unit 329, machining condition correction amount calculation unit 331, and machining condition correction unit 332 shown in Figures 1 and 9 are realized by the execution of a program stored in the storage unit 903 shown in Figure 17 by the control unit 901 shown in Figure 17. The nozzle shape acquisition unit 321, workpiece shape acquisition unit 322, machining condition acquisition unit 323, and gap acquisition unit 325 are also realized by the input unit 902 or communication unit 905 shown in Figure 17. Furthermore, the output unit 906 shown in Figure 17 is also used to realize the machining information output unit 333. The machining condition storage unit 324, nozzle information storage unit 326, and machining condition adjustment information storage unit 330 are realized by the storage unit 903 shown in Figure 17.

[0154] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention.

[0155] 10 Laser processing apparatus, 11 Table, 12 Laser oscillator, 13 Fiber cable, 14 Processing head, 15, 15a Processing nozzle, 16 Processing gas supply unit, 17 Gas piping, 18 Axis movement control unit, 30 Control device, 31 Processing program generation unit, 33 Apparatus control unit, 111 Jig, 141 Flow path, 151 Nozzle opening surface, 152 First cylindrical part, 153 Second cylindrical part, 321 Nozzle shape acquisition unit, 322 Workpiece shape acquisition unit, 323 Processing condition acquisition unit, 324 Processing condition storage unit, 325 Gap acquisition unit, 326 Nozzle information storage unit, 327 Inclination angle calculation unit, 328 Gap correction amount calculation unit, 329 Program generation unit, 330 Processing condition adjustment information storage unit, 331 Processing condition correction amount calculation unit, 332 Processing condition correction unit, 333 Processing information output unit, Cn Center axis, L: laser beam, On: nozzle origin, P: machining point, W: workpiece.

Claims

1. The laser cutting system comprises: a laser oscillator that emits laser light; a table on which a workpiece is placed; a cutting head that irradiates the workpiece with the laser light from the laser oscillator; a cutting nozzle provided on the laser light emission end side of the cutting head and spraying assist gas at the position where the laser light is irradiated onto the workpiece; an axis movement control unit that drives the table or the cutting head in the directions of mutually orthogonal X, Y, and Z axes, rotates the table or the cutting head about an inclination axis in the XY plane formed by the X and Y axes, and rotates the table or the cutting head about a rotation axis parallel to the Z axis; and a control unit that controls the laser oscillator and the axis movement control unit, wherein the control unit includes an inclination angle calculation unit that calculates the inclination angle between the nozzle opening surface, which is the workpiece-side surface of the cutting nozzle, and the surface of the workpiece at the laser cutting position of the workpiece. A laser processing apparatus comprising: a gap correction amount calculation unit that calculates a gap correction amount to correct a set gap amount between the nozzle opening surface and the surface of the workpiece using the inclination angle and the shape data of the processing nozzle; a processing condition correction amount calculation unit that calculates a correction amount for the laser processing conditions corresponding to the gap correction amount using processing condition adjustment information that shows the relationship between the change in the gap amount and the correction amount for the laser processing conditions; a processing condition correction unit that corrects the laser processing conditions using the correction amount for the laser processing conditions; and a device control unit that controls the axis movement control unit so that the corrected gap amount becomes the sum of the set gap amount and the gap correction amount.

2. The laser processing apparatus according to claim 1, characterized in that the laser processing conditions are at least one of the focal position of the laser beam, output power, pulse width, pulse period, frequency, duty cycle, and gas pressure of the assist gas.

3. The laser processing apparatus according to claim 2, characterized in that when the processing condition correction amount calculation unit adjusts the focal position of the laser beam, the correction amount of the focal position is equal to the gap correction amount.

4. The laser processing apparatus according to any one of claims 1 to 3, characterized in that the gap correction amount calculation unit calculates the gap correction amount using the radius in a direction perpendicular to the central axis of the processing nozzle, the inclination angle of the nozzle opening surface with respect to the XY plane, and the inclination angle between the surface of the workpiece and the nozzle opening surface.

5. The laser processing apparatus according to any one of claims 1 to 4, characterized in that the inclination angle calculation unit calculates the inclination angle from the shape of the processing position of the workpiece using the shape data of the processing nozzle and a three-dimensional model showing the shape of the workpiece processed to a desired shape.

6. The laser processing apparatus according to any one of claims 1 to 5, wherein the control unit further comprises a program generation unit that generates a processing path for performing laser processing using a three-dimensional model showing the shape of the workpiece processed to a desired shape, and generates a processing program including the processing path, and the program generation unit corrects the gap amount at the position in the processing program where the laser processing is performed using the gap correction amount.

7. The laser processing apparatus according to any one of claims 1 to 6, characterized in that the processing nozzle is a vertical processing nozzle having a nozzle opening surface perpendicular to the central axis of the processing nozzle, or an inclined processing nozzle having a nozzle opening surface inclined at an angle not perpendicular to the central axis.

8. A laser processing apparatus according to any one of claims 1 to 7, wherein the apparatus comprises a plurality of processing nozzles, and the gap correction amount calculation unit calculates the gap correction amount by referring to nozzle information which associates shape parameters with a correction amount calculation formula for calculating the gap correction amount for each shape of the processing nozzle when the processing nozzle is changed.

9. The laser processing apparatus according to claim 8, wherein the processing nozzle comprises a vertical processing nozzle having a nozzle opening surface perpendicular to the central axis of the processing nozzle, and an inclined processing nozzle having a nozzle opening surface inclined at a nozzle inclination angle that is not perpendicular to the central axis, and the gap correction amount calculation unit and the processing condition correction amount calculation unit select the processing nozzle to be used for laser processing according to the relationship between the inclination angle between the surface of the workpiece and the nozzle opening surface of the processing nozzle and the nozzle inclination angle of the inclined processing nozzle.

10. A laser processing method using a laser processing apparatus comprising: a laser oscillator that emits laser light; a table on which a workpiece is placed; a processing head that irradiates the workpiece with the laser light from the laser oscillator; a processing nozzle provided on the laser light emission end side of the processing head and spraying assist gas at the position where the laser light is irradiated onto the workpiece; an axis movement control unit that drives the table or the processing head in the directions of mutually orthogonal X, Y, and Z axes, rotates the table or the processing head about an inclination axis in the XY plane formed by the X and Y axes, and rotates the table or the processing head about a rotation axis parallel to the Z axis; and a control unit that controls the laser oscillator and the axis movement control unit, wherein the control unit performs an inclination angle calculation step of calculating the inclination angle between the nozzle opening surface, which is the workpiece-side surface of the processing nozzle, and the surface of the workpiece at the laser processing position of the workpiece, A laser processing method characterized by comprising: a gap correction amount calculation step in which the control unit calculates a gap correction amount to correct a set gap amount between the nozzle opening surface and the surface of the workpiece using the inclination angle and the shape data of the processing nozzle; a processing condition correction amount calculation step in which the control unit calculates a correction amount for the laser processing conditions corresponding to the gap correction amount using processing condition adjustment information that shows the relationship between the amount of change in the gap amount and the correction amount for the laser processing conditions; a processing condition correction step in which the control unit adjusts the laser processing conditions using the correction amount for the laser processing conditions; and a device control step in which the control unit controls the axis movement control unit so that the corrected gap amount is the sum of the set gap amount and the gap correction amount.

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