WO2016185614A1 - Laser processing device and laser processing method - Google Patents

Abstract

This laser processing device (1) includes: a mechanism (4G) that processes a workpiece (W) by turning a spot (SP) on the surface of the workpiece (W) irradiated by laser light (LL) and moving the spot (SP) away from the position where irradiation of the laser light (LL) started as turning of the spot (SP) of the laser light (LL) progresses; and a control device (31) that increases, from the start to the end of processing of the workpiece (W), the energy of the laser light (LL) from that used when the processing of the workpiece (W) started.

Description

Laser processing apparatus and laser processing method

The present invention relates to a laser processing apparatus and a laser processing method for irradiating a workpiece, which is a workpiece, with a laser beam to process a hole in the workpiece.

Processing devices using lasers are known. Patent Documents 1 and 2 describe a technique for forming a hole in a workpiece while rotating a laser beam in a spiral shape.

JP 2014-217860 A JP 2007-136471 A

When forming a hole in a workpiece while rotating the laser beam in a spiral manner, if a hole is drilled in a workpiece with a resin sandwiched between metals, there may be a trace that the resin has melted in the portion of the metal that does not penetrate. Thus, depending on the type of workpiece and the machining method, the quality of the workpiece after machining may deteriorate.

An object of the present invention is to suppress a reduction in processing quality of hole processing in which a hole is formed in a workpiece with a laser beam.

The laser processing apparatus of the present invention rotates a spot of the laser light irradiated on the surface of the workpiece, and moves the workpiece away from the position where the laser beam irradiation is started as the rotation proceeds, and a mechanism for processing the workpiece, And an apparatus for increasing the energy of the laser beam from the start to the end of the workpiece processing than when the workpiece processing is started.

The present invention can suppress the deterioration of the processing quality of the hole processing in which a hole is formed in a workpiece with a laser beam.

The perspective view which shows the laser processing apparatus which concerns on Embodiment 1. FIG. Sectional drawing which shows an example of the workpiece | work which the laser processing apparatus which concerns on Embodiment 1 processes The top view for demonstrating the hole processing by the laser processing apparatus concerning Embodiment 1 The figure for demonstrating the conditions at the time of the laser processing apparatus which concerns on Embodiment 1 performing locus processing Sectional drawing for demonstrating the hole processing by the laser processing apparatus concerning Embodiment 1 Sectional drawing for demonstrating the hole processing by the laser processing apparatus concerning Embodiment 1 Sectional drawing for demonstrating the hole processing by the laser processing apparatus concerning Embodiment 1 The figure which shows the relationship between the energy of the laser beam and the moving speed of the spot of a laser beam when the laser processing apparatus which concerns on Embodiment 1 carries out hole processing The figure which shows the overlap of the spot of a laser beam in case the laser processing apparatus 1 which concerns on Embodiment 1 carries out hole processing The figure which shows the modification of the relationship with the energy of the laser beam in case the laser processing apparatus which concerns on Embodiment 1 carries out hole processing The figure which shows the modification of the relationship with the energy of the laser beam in case the laser processing apparatus which concerns on Embodiment 1 carries out hole processing The figure which shows the modification of the method in which the laser processing apparatus which concerns on Embodiment 1 moves the spot of a laser beam in locus processing Flowchart of laser processing method according to Embodiment 1

Hereinafter, the laser processing apparatus according to the embodiment will be described in detail with reference to the drawings. The present invention is not limited to the embodiments shown below.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a laser processing apparatus according to the first embodiment. The laser processing apparatus 1 according to the first embodiment rotates the spot SP of the laser beam LL irradiated on the surface of the workpiece W, and moves it away from the position where the irradiation of the laser beam LL is started as the rotation progresses. A mechanism 4G that processes the workpiece W, and a laser oscillation device 9 that is an apparatus that increases the energy of the laser beam LL from the start to the end of the processing of the workpiece W, compared to when the processing of the workpiece W is started. ,including.

The laser processing apparatus 1 performs processing such as cutting or drilling on the workpiece W. The processing head 4 includes a mechanism 4G and an optical system 7. The mechanism 4G changes the irradiation direction of the laser light LL. The optical system 7 included in the processing head 4 includes an fθ lens that forms an image of the laser light LL emitted from the mechanism 4G on the surface of the work W of the table 2 and a focus adjustment mechanism that adjusts the focus of the laser light LL. The structure and operation of the mechanism 4G will be described later. The dust collection duct 8 sucks dust generated when the workpiece W is processed by the laser beam LL emitted from the processing head 4.

The table 2 includes a first surface 2Ps on which the workpiece W is placed, a second surface 2Pr facing the first surface 2Ps, and side surfaces 2SA, 2SB, 2SC, 2SD that connect the first surface 2Ps and the second surface 2Pr. Have The shapes of the first surface 2Ps and the second surface 2Pr are both rectangular. The rectangle includes a square. For this reason, the shape of the table 2 is a rectangular parallelepiped.

The table 2 places the workpiece W on the machining area 2WA of the first surface 2Ps. The processing area 2WA is an area inside the outer edge 2EG of the first surface 2Ps. The processing head 4 cannot process an object outside the processing area 2WA. The table 2 moves in two directions: a first direction that is parallel to one side of the first surface 2Ps and the second surface 2Pr, and a second direction that intersects the first direction. The direction orthogonal to the first direction and the second direction is the third direction. In the first embodiment, the first direction and the second direction are orthogonal, that is, intersect at 90 degrees, but the first direction and the second direction may intersect at other than 90 degrees. In the following, the first direction is referred to as the X direction, the second direction is referred to as the Y direction, and the third direction is referred to as the Z direction. The first mirror 5M of the first mechanism 5 changes the irradiation direction of the laser light LL along the X direction which is the first direction, and the second mirror 6M of the second mechanism 6 changes the irradiation direction of the laser light LL to the first direction. It changes along the Y direction which is two directions. The first mirror 5M and the second mirror 6M are galvanometer mirrors.

In Embodiment 1, the processing head 4 is fixed to the stationary system of the laser processing apparatus 1, and the table 2 moves. Therefore, the driving devices 10 and 20 change the relative position between the machining head 4 and the table 2 by moving the table 2. In the first embodiment, the driving device 10 changes the relative position between the machining head 4 and the table 2 in the X direction. The drive device 20 changes the relative position between the machining head 4 and the table 2 in the Y direction. Hereinafter, the driving device 10 is appropriately referred to as a first driving device 10, and the driving device 20 is appropriately referred to as a second driving device 20.

The first drive device 10 includes a base 11, rails 12A and 12B, guide members 13A and 13B, a nut 14, a screw 15, and an actuator 16. The base 11 has rails 12A and 12B and an actuator 16 attached thereto and supports them. The rails 12A and 12B extend along the X direction. Both rails 12A, 12B are arranged parallel to each other. The guide member 13A is attached to the rail 12A and moves in the direction in which the rail 12A extends, that is, the X direction. The guide member 13B is attached to the rail 12B and moves in the direction in which the rail 12B extends.

The guide members 13A and 13B are attached to the base 21 of the second drive device 20. Since the guide members 13A and 13B move along the rails 12A and 12B, the base 21 also moves along the rails 12A and 12B.

The nut 14 is attached to the base 21 of the second drive device 20. The screw 15 is screwed into the nut 14. In Embodiment 1, the actuator 16 is an electric motor. A screw 15 is attached to the shaft of the actuator 16. As the screw 15 rotates, the nut 14 moves in the direction in which the screw 15 extends, so that the base 21 to which the nut 14 is attached moves in the direction in which the screw 15 extends. In the first embodiment, the extending direction of the screw 15 is the same X direction as the extending direction of the rails 12A and 12B. Therefore, when the screw 15 rotates, the base 21 moves along the rails 12A and 12B. The actuator 16 rotates the screw 15 to move the base 21 along the rails 12A and 12B.

The actuator 16 has an encoder 17. In the first embodiment, the encoder 17 is a rotary encoder. The encoder 17 detects the rotation angle of the shaft of the actuator 16, that is, the rotation angle of the screw 15. The actuator 16 is controlled by the first driver 30X.

The second drive unit 20 includes a base 21, rails 22A and 22B, guide members 23A and 23B, a nut 24, a screw 25, and an actuator 26. The base 21 is attached with rails 22A and 22B and an actuator 26 to support them. The rails 22A and 22B extend along the Y direction. Both rails 22A and 22B are arranged parallel to each other. The guide member 23A is attached to the rail 22A and moves in the direction in which the rail 22A extends, that is, the Y direction. The guide member 23B is attached to the rail 22B and moves in the direction in which the rail 22B extends.

The guide members 23A and 23B are attached to the table 2. Since the guide members 23A and 23B move along the rails 22A and 22B, the base 21 also moves along the rails 22A and 22B.

The nut 24 is attached to the base 21 of the second drive device 20. The screw 25 is screwed into the nut 24. In the first embodiment, the actuator 26 is an electric motor. A screw 25 is attached to the shaft of the actuator 26. As the screw 25 rotates, the nut 24 moves in the direction in which the screw 25 extends, so that the table 2 to which the nut 24 is attached moves in the direction in which the screw 25 extends. In the first embodiment, the extending direction of the screw 25 is the same Y direction as the extending direction of the rails 22A and 22B. Therefore, when the screw 25 rotates, the table 2 moves along the rails 22A and 22B. The actuator 26 moves the table 2 along the rails 22A and 22B by rotating the screw 25.

The actuator 26 has an encoder 27. In the first embodiment, the encoder 27 is a rotary encoder. The encoder 27 detects the rotation angle of the shaft of the actuator 26, that is, the rotation angle of the screw 25. The actuator 26 is controlled by the second driver 30Y.

The table 2 is attached to the first drive device 10 via the second drive device 20. The first drive device 10 moves the table 2 in the X direction via the second drive device 20, more specifically, the base 21, the actuator 26, the screw 25, and the nut 24. The second driving device 20 directly moves the table 2 in the Y direction. Since the rotation angle of the screw 15 that moves the table 2 in the X direction is proportional to the feed amount of the nut 14, the amount of movement of the table 2 in the X direction is obtained from the detection value of the encoder 17. Since the rotation angle of the screw 25 that moves the table 2 in the Y direction is proportional to the feed amount of the nut 24, the amount of movement of the table 2 in the Y direction is obtained from the detection value of the encoder 27.

In the first embodiment, at least one of the first driving device 10 and the second driving device 20 changes the relative position between the processing head 4 and the table 2, but the present invention is not limited to this. The relative position between the machining head 4 and the table 2 may be changed by moving the machining head 4 while the table 2 is stationary. Further, the relative position between the processing head 4 and the table 2 is changed by moving the table 2 in either the X direction or the Y direction and moving the processing head 4 in a direction different from the moving direction of the table 2. May be.

Next, the mechanism 4G will be described. The mechanism 4G includes a first mechanism 5 and a second mechanism 6. The first mechanism 5 includes a first mirror 5M and a first actuator 5A. The first mirror 5M reflects the laser beam LL emitted from the laser oscillation device 9 toward the second mechanism 6. The first actuator 5A changes the irradiation direction of the laser light LL toward the second mechanism 6 by changing the inclination of the first mirror 5M. The second mechanism 6 includes a second mirror 6M and a second actuator 6A. The second mirror 6M reflects the laser beam LL reflected by the first mirror 5M of the first mechanism 5 toward the table 2. The second actuator 6A changes the irradiation direction of the laser light LL toward the table 2 by changing the inclination of the second mirror 6M.

The first mirror 5M of the first mechanism 5 changes the irradiation direction of the laser light LL along the first direction. The second mirror 6M of the second mechanism 6 changes the irradiation direction of the laser light LL along the second direction. The first direction and the second direction intersect each other, and in the first embodiment, are orthogonal to each other. By operating at least one of the first mirror 5M and the second mirror 6M, the mechanism 4G can move the spot SP of the laser beam LL irradiated on the surface of the workpiece W. At this time, the mechanism 4G can move the spot SP along a straight line or a curve, and can also draw a circle on the spot SP or move the spot SP along a spiral.

In the first embodiment, the laser beam LL is a UV (Ultra Violet) laser or a carbon dioxide laser, but the type is not limited. The type of the laser beam LL is selected in accordance with the type and processing method of the workpiece W to be processed by the laser processing apparatus 1. In the first embodiment, the first actuator 5A and the second actuator 6A are electric motors. However, the first actuator 5A and the second mirror 6M need only be changed, and are not limited to electric motors.

In the first embodiment, the laser processing apparatus 1 is controlled by the control device 31. As shown in FIG. 1, the control device 31 includes a processing unit 32, a storage unit 33, and an input / output unit 34. The processing unit 32 is a processor such as a CPU (Central Processing Unit). The storage unit 33 is a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a storage device, or a storage device that combines these. The input / output unit 34 is an interface circuit that serves as an interface between the control device 31 and an external device connected to the control device 31.

The first actuator 5A, the second actuator 6A, the laser oscillation device 9, the encoders 17 and 27, the first driver 30X, the second driver 30Y, and the input device 35 shown in FIG. 1 are connected to the input / output unit 34. The processing unit 32 acquires the detection values of the encoders 17 and 27 and the information input from the input device 35 via the input / output unit 34. Further, the processing unit 32 transmits control signals to the first actuator 5A, the second actuator 6A, the laser oscillation device 9, the first driver 30X, and the second driver 30Y via the input / output unit 34.

The storage unit 33 stores a computer program for the control device 31 to execute processing for controlling the laser processing device 1. The processing unit 32 reads the computer program described above from the storage unit 33 and controls the laser processing apparatus 1. Specifically, the processing unit 32 moves the spot SP of the laser light LL irradiated on the surface of the workpiece W by controlling the first actuator 5A and the second actuator 6A of the mechanism 4G. Further, the processing unit 32 controls the laser oscillation device 9 to switch between irradiation of the laser beam LL and stop of irradiation, or change the energy of the laser beam LL.

The control device 31 controls the actuator 16 via the first driver 30X and controls the actuator 26 via the second driver 30Y. The control device 31 controls the actuator 16 and the actuator 26 using the detection value of the encoder 17 and the detection value of the encoder 27. The detection value of the encoder 17 is the rotation angle of the shaft of the actuator 16 and the screw 15, and the detection value of the encoder 27 is the detection value of the encoder 27, that is, the rotation angle of the shaft of the actuator 26 and the screw 25.

The input device 35 is a device for inputting a command and data for operating the laser processing apparatus 1. The input device 35 includes an input unit 35I and a display unit 35M. In the first embodiment, the input unit 35I is a keyboard, a button, or a touch panel, but is not limited thereto. The display unit 35M is a liquid crystal display, but is not limited to this. The display unit 35 </ b> M can display information stored in the storage unit 33 of the control device 31 and information on errors that have occurred in the laser processing apparatus 1. The information displayed on the display unit 35M is not limited to these.

FIG. 2 is a cross-sectional view showing an example of a workpiece machined by the laser machining apparatus according to the first embodiment. In the first embodiment, the workpiece W that is a processing target of the laser processing apparatus 1 is a substrate to which an electronic component is attached, more specifically, a printed substrate. The laser processing apparatus 1 performs the hole processing for forming the hole H in the workpiece W by executing the laser processing method according to the first embodiment. The workpiece W is a multilayer substrate having a first layer WA, a second layer WB, and a third layer WC. The workpiece W has a structure in which a metal first layer WA and a metal third layer WC sandwich a resin second layer WB. In Embodiment 1, the metal of the first layer WA and the third layer WC is copper or a copper alloy, and the resin of the second layer WB is polyimide, but is not limited to these materials. The metal of the first layer WA and the third layer WC may be aluminum or an aluminum alloy, and the resin of the second layer WB may be a phenol resin.

穴 Drilling is roughly divided into two types. The first method is a method of condensing and processing the laser beam LL to approximately the diameter of the hole H to be processed. In the second method, the laser beam LL is condensed to a diameter smaller than the diameter of the hole H to be processed, and the laser beam LL is irradiated while changing the irradiation position of the laser beam LL by the first mirror 5M and the second mirror 6M of the mechanism 4G. In this method, the light LL is turned and processed to move away from the center of turning. Hereinafter, the processing by the second method is appropriately referred to as locus processing. The first method is used when the diameter of the hole H to be processed is small, and the second method is used when the diameter of the hole H to be processed is large. Since the laser beam LL needs to be collected and processed from the relationship of the energy density of the laser beam LL necessary for processing, the second method is used when the diameter of the hole H to be processed is large.

Carbon dioxide lasers are easy to obtain high output and easy to maintain, but there are some workpieces that are difficult to machine at the wavelength of carbon dioxide lasers. When copper is used as the metal of the first layer WA and the third layer WC of the workpiece W, the carbon dioxide laser has a low absorption rate for copper, so that it is difficult to process with the carbon dioxide laser. For this reason, when drilling the first layer WA and the third layer WC made of copper, a UV laser may be used. In addition, by covering the copper surface with a substance having a high absorption rate of carbon dioxide laser, the first layer WA and the third layer WC made of copper can be drilled with a carbon dioxide laser.

Since it is difficult to obtain a high output of the UV laser, the laser processing apparatus 1 condenses the laser light LL to increase the energy density, and operates the first mirror 5M and the second mirror 6M of the mechanism 4G. A hole may be formed by locus processing while changing the irradiation position of the laser beam LL. Specifically, the laser beam LL is squeezed with respect to the workpiece W by the fθ lens provided in the optical system 7 shown in FIG. Assume that the condensing point of the laser beam LL, that is, the diameter at the spot SP of the laser beam LL is 25 μm. In this case, the mechanism 4G of the laser processing apparatus 1 performs the locus processing so that the processing range of the diameter 25 μm by the spot SP overlaps little by little for each pulse of the laser beam LL, thereby making the hole H larger than the diameter 25 μm in the workpiece W. Can be processed.

There are two types of hole drilling in the substrate: blind hole drilling and through hole drilling. When processing a workpiece W using a UV laser, a hole is often processed up to the first layer WA and the second layer WB, and a blind hole is formed that stops at the surface of the third layer WC. When performing such blind hole processing, the laser processing apparatus 1 first focuses the laser beam LL on the surface of the first layer WA of the workpiece W, and processes the first layer WA by trajectory processing. Next, the laser processing apparatus 1 reduces the output of the laser beam LL to reduce the energy density of the laser beam LL with respect to the second layer WB. The energy density at this time is such that the second layer WB, which is resin, can be processed, but the third layer WC, which is copper, cannot be processed. As another method for reducing the energy density of the laser beam LL, the output of the laser beam LL is not decreased, and the focal position of the laser beam LL with respect to the workpiece W is shifted, thereby shifting the laser beam LL on the surface of the second layer WB. Increase the diameter to reduce the energy density. Only the second layer WB may be processed by reducing the energy density of the laser beam LL by such a method.

The above-described blind hole processing does not process the first layer WA and the second layer WB every time one hole H is processed, but after all the holes have been processed for the first layer WA, Is changed, and the second layer WB is drilled for all the holes H. By doing in this way, since the frequency | count of switching of processing conditions decreases, the fall of productivity is suppressed.

As the locus processing, there is one in which only the outer periphery of the hole H of the first layer WA is processed to leave the central portion and the central portion is removed together when the second layer WB is processed. In the case of this trajectory machining, the productivity is high because the machining is performed only on the outer periphery, but when the second layer WB is machined, the central part is skipped and removed, so it may be unclear whether the central part can be removed reliably. There is sex. Moreover, if the center part skipped when the 2nd layer WB was processed cannot fully collect dust, the frequency which cleans the laser processing apparatus 1 will increase, and the fall of productivity may be caused.

For this reason, there is a trajectory machining that processes from the center along a trajectory along the spiral. When the trajectory machining along the spiral is performed, the laser machining apparatus 1 first positions the laser beam LL at the center C of the hole H, and moves away from the center C while rotating the laser beam LL from this point. The laser beam LL is moved. In the locus processing, the mechanism 4G first positions the laser beam LL at the center C of the hole H, and then moves the spot SP of the laser beam LL along the spiral. Immediately after the laser beam LL starts to move, the speed at which the spots SP move is low, so that the overlapping ratio of the spots SP increases. As a result, a trace of the second layer WB melting may remain in the third layer WC in contact with the second layer WB. As described above, in the case of locus processing in which the laser beam LL is moved along the spiral, the third layer WC in the center portion of the hole H may be excessively processed. In particular, when the repetition frequency of the laser oscillation device 9 is increased in order to improve productivity, a large amount of laser light LL is irradiated onto the workpiece W in a short time, so that the center portion may be excessively processed due to the effect of heat storage. Increases nature.

In the hole machining, there is a method in which the start of the spiral trajectory is shifted from the center C in order to avoid excessive machining of the central portion of the third layer WC. Further, in the hole processing for moving the laser beam LL from the center C toward the outer periphery, the amount of movement in the radial direction for each turn when the laser beam LL moves along the spiral is increased so that the laser at the center portion. There is a method of reducing the number of irradiation with the light LL. However, according to these methods, the first layer WA may remain in the center of the hole H depending on the conditions, and it is difficult to select conditions that match the specifications of the workpiece W.

The locus machining is not performed after confirming the completion of positioning by the mechanism 4G for each pulse. In executing the locus machining, the laser processing apparatus 1 operates the mechanism 4G while operating the mechanism 4G in a state where the laser oscillation device 9 generates pulses of the laser beam LL continuously from the machining start point to the machining end point. Process. For this reason, in the locus machining, it is difficult to change the machining pitch in one spiral locus.

In the first embodiment, the mechanism 4G of the laser processing apparatus 1 turns the spot SP of the laser beam LL irradiated on the surface of the workpiece W and moves away from the position where the irradiation of the laser beam LL is started as the turning progresses. To move the workpiece W. The laser oscillation device 9 increases the energy of the laser light LL between the start and end of processing of the workpiece W, compared to when the processing of the workpiece W is started. By such locus processing, the laser processing apparatus 1 causes the third layer WC to be excessive in the center portion of the hole H when drilling, more specifically, blind hole processing, in the third layer WC of the workpiece W. To prevent the machining quality from being lowered. Further, since the laser processing apparatus 1 processes the first layer WA from the central portion, the central portion of the first layer WA can be reliably removed.

FIG. 3 is a plan view for explaining hole processing by the laser processing apparatus according to the first embodiment. FIG. 4 is a diagram for explaining conditions when the laser machining apparatus according to Embodiment 1 executes locus machining. 5 to 7 are cross-sectional views for explaining hole processing by the laser processing apparatus according to the first embodiment.

When the mechanism 4G of the laser processing apparatus 1 performs the hole processing on the first layer WA of the workpiece W by the locus processing, the position of the spot SP of the laser beam LL at the start of processing is set to the center of the hole H to be formed. Position to C. If positioning is completed, the laser processing apparatus 1 will start the hole processing by locus processing. Specifically, the laser oscillation device 9 starts irradiating the laser beam LL, and the mechanism 4G operates the first mirror 5M and the second mirror 6M to spiral the spot SP of the laser beam LL on the surface of the workpiece W. Move along. By such processing, the spot SP of the laser beam LL is swung along the spiral.

As shown in FIG. 4, at the time of drilling by turning, the locus LS of the spot SP of the laser beam LL is from the center C of the hole H to be formed to the outer periphery HE of the hole H shown in FIG. , Spiral or spiral. The spiral locus LS is set with the movement amount Δd to the outside in the radial direction DD as a parameter for each rotation. When the movement amount Δd in the radial direction DD is relatively small, the spot SP of the laser beam LL circulates a plurality of times from the center C of the hole H to the outer periphery HE and reaches the outer periphery HE. When the movement amount Δd in the radial direction DD is relatively large, the spot SP of the laser beam LL is smaller in the center of the hole H than the case where the movement amount Δd in the radial direction DD is relatively small. From C to the outer periphery HE.

When the hole processing by the locus processing is started, the spot SP of the laser beam LL moves outside the radial direction DD by a movement amount Δd while turning around the center C. In the process, as shown in FIGS. 5 and 6, the first layer WA of the workpiece W is melted and removed, and a processed portion U is formed. From the processed portion U, the second layer WB is exposed. The spot SP of the laser beam LL moves to the outside of the radial direction DD while turning, and reaches the outer periphery HE of the hole H at the position PE of the locus LS. The spot SP of the laser beam LL repeats turning a plurality of times at the position of the outer periphery HE of the hole H. Thereafter, the laser oscillation device 9 stops the laser beam irradiation, and the hole processing by the trajectory processing is completed. When the hole machining is completed, a hole H is formed in the first layer WA of the workpiece W as shown in FIG.

As described above, immediately after the spot SP of the laser beam LL starts moving, the moving speed of the spot SP is low, so that the overlapping ratio of the spots SP increases. In this case, the laser processing apparatus 1 performs hole processing by reducing the energy of the laser beam LL. That is, the laser oscillation device 9 of the laser processing apparatus 1 increases the energy of the laser light LL when the speed of movement of the spot SP of the laser light LL is larger than when the speed of movement is low.

By such processing, the laser processing apparatus 1 can suppress deterioration in processing quality due to excessive processing of the third layer WC. As the hole machining by the locus machining progresses, that is, as the number of rounds of the spot SP of the laser beam LL increases, the moving speed of the spot SP increases and the overlapping ratio of the spots SP decreases. In this case, the laser processing apparatus 1 continues the hole processing by increasing the energy of the laser beam LL from that at the start of the hole processing. By such processing, the laser processing apparatus 1 can reliably remove the first layer WA even when the moving speed of the spot SP of the laser beam LL increases.

FIG. 8 is a diagram showing the relationship between the laser beam energy and the moving speed of the laser beam spot when the laser processing apparatus according to the first embodiment performs hole processing. PS in FIG. 8 is the number of pulses of the laser light LL irradiated onto the workpiece W. PSs indicates the number of pulses at the timing when the laser processing apparatus 1 starts drilling. PSc indicates the number of pulses at which the energy E of the laser beam LL is made larger than that at the start of drilling. PSe indicates the timing when the hole processing by the laser processing apparatus 1 is completed.

As shown in FIG. 8, the moving speed Vc of the spot SP of the laser beam LL increases immediately after the laser processing apparatus 1 starts drilling until a certain number of pulses PS is reached or until a certain time t elapses. To do. The moving speed Vc is a peripheral speed. In the first embodiment, the laser processing apparatus 1 irradiates the workpiece W with the laser beam LL having the first energy E1 until the pulse number PSc, and the workpiece W receives the laser beam LL having the second energy E2 after the pulse number PSc. Irradiate. At the timing of the pulse number PSc, the diameter of the processed portion U is Dc as shown in FIGS. After the number of pulses PSc, the laser processing apparatus 1 rotates the spot SP along the spiral while irradiating the workpiece W with the laser beam LL of the second energy E2, and the outer diameter HE of the hole H, that is, the diameter D When the position is reached, the spot SP is circulated a plurality of times at the position. The energy E of the laser beam LL is preferably maximized at the outer periphery HE of the hole H. By doing in this way, the laser processing apparatus 1 can remove the 1st layer WA of outer periphery HE reliably.

FIG. 9 is a diagram showing laser beam spot overlap when the laser processing apparatus 1 according to the first embodiment performs hole processing. The timing at which the laser processing apparatus 1 increases the energy E of the laser beam LL than when the processing is started may be a timing at which the overlap ke of the spots SP of the adjacent laser beams LL becomes equal to or greater than a predetermined value. it can. The size of the overlap ke can be obtained from the moving speed Vc of the spot SP of the laser beam LL and the diameter ds of the spot SP. The pulse number PSc at which the energy E of the laser beam LL is changed is determined when determining the machining condition of the workpiece W, and is stored in the storage unit 33 of the control device 31 shown in FIG.

When the laser processing apparatus 1 forms a hole H having a diameter of 100 μm on the workpiece W by hole processing by trajectory processing, the laser light LL is focused to a diameter of 25 μm by the fθ lens provided in the optical system 7. When the mechanism 4G processes the outer periphery HE of the hole H, the operation amount and the operation speed of the first mirror 5M and the second mirror 6M are determined so that the overlap ke is 5 μm. The spiral trajectory LS moves 15 μm in the radial direction DD every time the spot SP of the laser beam LL makes one revolution. That is, the movement amount Δd is 15 μm. With respect to the locus LS set in this way, the operation amount and the operation speed of the first mirror 5M and the second mirror 6M are calculated and stored in the storage unit 33 of the control device 31. The pulse number PSc for increasing the energy E of the laser beam LL is equal to the pulse number PS when the overlap ke of the spot SP of the laser beam LL is smaller than the overlap ke at the start of processing and larger than the overlap ke at the outer periphery HE. Is set. The set pulse number PSc is stored in the storage unit 33 of the control device 31. The energy E of the laser beam LL is set so that the energy E2 when the outer periphery HE is processed is maximized, and the energy E1 from the start of processing to the number of pulses PSc is ½ of the energy E2. The energy E1, E2 is stored in the storage unit 33 of the control device 31. The control device 31 drills the workpiece W by trajectory machining using the operation amount, operation speed, pulse number PSc, and energy E1, E2 of the first mirror 5M and the second mirror 6M stored in the storage unit 33.

When the laser oscillation device 9 is a Q switch system, the control device 31 of the laser processing device 1 changes the energy of the laser light LL by changing the gate width of the Q switch. In the hole machining by the locus machining, the control device 31 controls the laser oscillation device 9 with the gate width that becomes the energy E1 from the machining start to the pulse number PSc. The control device 31 controls the laser oscillation device 9 with the gate width of energy E2 after the pulse number PSc. When processing the outer periphery HE of the hole H, the control device 31 controls the laser oscillation device 9 so that the energy E becomes maximum. When processing the outer periphery HE of the hole H, the control device 31 does not determine the number of pulses PS of the laser beam LL, and stops the irradiation of the laser beam LL when the control of the first mirror 5M and the second mirror 6M is completed. To do.

10 and 11 are diagrams showing modifications of the relationship with the energy of the laser beam when the laser processing apparatus according to the first embodiment performs hole processing. In the above-described example, the laser oscillation device 9 of the laser processing apparatus 1 increases the energy E of the laser beam LL in two steps of energy E1 and E2 from the start to the end of processing, but increases the energy E stepwise. It is not limited to two stages. The laser oscillation device 9 may change the energy E of the laser beam LL in three stages of E1, E1u, and E2, as shown in FIG. In this case, the energy changes from energy E1 to energy E2 at the number of pulses PSc1, and changes from energy E1u to energy E2 at the number of pulses PSc2. The energy E2 is energy when the output of the laser oscillation device 9 is maximum. Since the energy E of the laser beam LL is increased stepwise, the control of the laser oscillation device 9 can be simplified.

The laser oscillation device 9 of the laser processing device 1 may continuously increase the energy E of the laser beam LL as shown in FIG. In this case, the laser processing apparatus 1 increases the energy E as the number of pulses PS increases from the start of processing, and sets the maximum value Emax of the energy E at the number of pulses PSc. That is, the energy E of each pulse of the laser beam LL is determined so that the maximum value Emax is obtained at the outer periphery HE of the hole H. The pulse number PSc can be set to the pulse number at the timing when the spot SP of the laser beam LL reaches the outer periphery HE of the hole H, but is not limited thereto. As described above, the number of pulses PS when the overlap ke of the spot SP of the laser beam LL is smaller than the overlap ke at the start of processing and larger than the overlap ke at the outer periphery HE may be used. By continuously increasing the energy E of the laser beam LL, the energy E of the laser beam LL can be easily controlled in accordance with the moving speed Vc of the spot SP of the laser beam LL.

FIG. 12 is a diagram showing a modification of the method for moving the laser beam spot in the locus processing by the laser processing apparatus according to the first embodiment. In the above description, the mechanism 4G of the laser processing apparatus 1 moves the spot SP of the laser beam LL along the spiral. That is, the mechanism 4G continuously changes the position of the spot SP in the radial direction DD so that when the spot SP of the laser beam LL makes one round around the center C, the spot SP moves by the movement amount Δd in the radial direction DD. I let you.

In the modification, the mechanism 4G of the laser processing apparatus 1 causes the circular motion that makes one round around the center C to be the spot SP, and then moves it by the movement amount Δd in the radial direction DD, and makes one round around the center C. Make a circular motion. This is repeated up to the outer periphery HE of the hole H. That is, in the modification, the mechanism 4G moves the spot SP stepwise in the radial direction DD by the movement amount Δd every time the spot SP of the laser beam LL makes one round around the center C. Thus, even if the spot SP of the laser beam LL is moved along the trajectories LS1, LS2, LS3, LS4, and LS5, the laser processing apparatus 1 can drill the workpiece W by the trajectory processing.

FIG. 13 is a flowchart of the laser processing method according to the first embodiment. The laser processing method according to the first embodiment is realized by the control device 31 shown in FIG. The flowchart shown in FIG. 13 is an example in which the energy E of the laser beam LL increases stepwise. The control device 31 positions the position where the workpiece W is irradiated with the laser light LL at the center C of the hole H to be formed in the workpiece W. In step S101, the control device 31 controls the laser oscillation device 9 to start irradiating the workpiece W placed on the table 2 with the laser beam LL and the spot SP of the laser beam LL at the center C. Rotate around. That is, the control device 31 turns the spot SP of the laser beam LL and moves it away from the position where the irradiation of the laser beam LL starts, that is, the center C as the turning of the spot SP progresses.

The control device 31 reads out the pulse number PSc at the timing of increasing the energy E of the laser beam LL from the storage unit 33 and compares it with the current pulse number PS. If the current number of pulses PS is not the number of pulses PSc, the control device 31 determines in step S102 that it is not time to change the energy E of the laser beam LL (step S102, No). In this case, the control device 31 causes the laser oscillation device 9 to continue irradiation with the laser light LL with the current energy E in step S103.

If the current number of pulses PS is the number of pulses PSc, the control device 31 determines in step S102 that it is time to change the energy E of the laser beam LL (step S102, Yes). In this case, the control device 31 increases the energy E of the laser beam LL in step S104. That is, the control device 31 increases the energy E of the laser beam LL between the start and end of processing of the workpiece W, compared to when the processing of the workpiece W is started. Specifically, the control device 31 causes the laser oscillation device 9 to irradiate the laser beam LL with an energy E larger than the current energy E.

In step S105, the control device 31 determines whether or not the spot SP of the laser beam LL has reached the outer periphery HE of the hole H. When the spot SP has not reached the outer periphery HE of the hole H (No in step S105), in step S106, the laser oscillation device 9 is continuously irradiated with the laser beam LL with the energy E increased in step S104. When the spot SP has reached the outer periphery HE of the hole H (Yes in step S105), in step S107, the control device 31 sets the energy E of the laser beam LL as the maximum value and makes a plurality of spots of the laser beam LL go around. Then, the laser oscillation device 9 is controlled to stop the irradiation with the laser beam LL. Through such processing, a hole H is formed in the first layer WA of the workpiece W. When the hole H is formed, the laser processing apparatus 1 performs the hole processing on the second layer WB at the position of the hole H.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 laser processing device, 2 table, 4 machining head, 4G mechanism, 5 first mechanism, 5A first actuator, 5M first mirror, 6 second mechanism, 6A second actuator, 6M second mirror, 7 optical system, 8 Dust collection duct, 9 laser oscillation device, 10 first drive device, 20 second drive device, 31 control device, 32 processing unit, 33 storage unit, 34 input / output unit, 35 input device, H hole, HE outer periphery, LL laser Light, SP spot, U processed part, W workpiece, WA first layer, WB second layer, WC third layer.

Claims (5)

A mechanism for processing the workpiece by rotating a spot of the laser beam irradiated on the surface of the workpiece and moving the laser beam away from a position where the irradiation of the laser beam is started as the rotation progresses;
An apparatus for increasing the energy of the laser beam between the start and end of processing of the workpiece, compared to when the processing of the workpiece is started;
A laser processing apparatus comprising: The device is
2. The laser processing apparatus according to claim 1, wherein the energy of the laser light is increased when the moving speed of the spot is higher than when the moving speed is low. The device is
The laser processing apparatus according to claim 1, wherein the energy of the laser light is increased stepwise. The device is
The laser processing apparatus according to claim 1, wherein the energy of the laser beam is continuously increased. Irradiating the surface of the workpiece with laser light;
The laser beam spot is swung, and moved away from the position where the irradiation of the laser beam is started as the turning proceeds, and the energy of the laser beam is changed from the start to the end of machining the workpiece. A process of making the workpiece larger than when machining of the workpiece was started,
Stopping the laser light irradiation;
A laser processing method comprising:

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