JP2005169465A - Laser beam machining method, apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance machining accuracy in boring a hole of a prescribed shape on a workpiece. <P>SOLUTION: The controller 28 of a laser beam machining apparatus 10 controls the driving of each operating part such as a trepanning head 14, a workpiece supporting part 17, and an XY table 18, on the basis of a control program stored preliminarily in a storage section, controlling also a voltage application to a laser oscillator 12 to control the output level of a laser beam. While the laser beam outgoing from a machining nozzle 16 is emitted to the machining point of a workpiece 30 preset in a first machining process at the time of boring, the controller 28 moves the machining nozzle 16 along the contour of a hole to be machined, working a part fused by the laser beam so as to leave the part in a cutting groove. Then, in a second machining process, the controller 28 moves the machining nozzle 16 again along the contour of the hole, controlling so that the fused part left in the cutting groove in the first machining process is cut off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser processing method, a laser processing apparatus, and a laser processing program for processing so as to improve the processing accuracy of a processing surface when a processing object is irradiated with laser light to drill a through hole of an arbitrary shape. About.

  Conventionally, as processing using laser light (hereinafter referred to as laser processing), processing techniques such as welding, drilling or cutting are used in manufacturing processes in various fields such as machines, electronics, and semiconductor devices.

  For example, a solder paste is printed on a printed wiring board using a metal mask for screen printing. In such a metal mask, a large number of through holes corresponding to a large number of soldering locations are provided, and the contour shape of each through hole is formed in an arbitrary shape corresponding to the connection pattern of the soldering portion. .

  As a method for processing a metal mask, a method is used in which a metal mask, which is an object to be processed (work), is irradiated with laser light and a through hole corresponding to a soldered portion is formed with high accuracy.

  By the way, in the processing of an object to be processed by laser light, particularly in cutting or drilling, an oxidation product called dross is attached to the processed surface formed by the processing and the back surface with respect to laser light irradiation. In recent years, since high-precision processing is required, the adhesion of dross becomes an obstacle at the time of screen printing, so that the printing accuracy is lowered.

  When laser processing the metal mask, it is necessary to suppress the occurrence of dross in order to increase the printing accuracy of the solder paste by screen printing.

As a means for solving such a problem, for example, a method of removing dross attached to the back side of a processed surface formed by laser processing by emitting laser light and assist gas to a processing location is used. (For example, refer to Patent Document 1).
JP 2003-285191 A

  For example, when a through hole having a circular contour is drilled in a workpiece, laser light is emitted at the processing start position, and the nozzle is moved circularly so that the laser light follows the contour of the hole. Then, the laser beam irradiation position moves from the machining start position so as to have a predetermined radius of curvature. However, when the laser beam makes a round along the outline of the through hole to be machined, the laser beam returns to the irradiation start position again. Shaped through-holes can be opened.

  However, the circular removed portion cut by the laser beam immediately before the laser beam returns to the processing start position is tilted by the gas pressure or gravity of the assist gas, and the removed portion is cut just before the final portion is cut by the laser beam. Will fall. For this reason, in the conventional processing method, the removed portion is separated from the object to be processed so that the final cut portion is peeled off, and a portion that remains uncut (a jagged cut surface) is formed on the inner periphery of the through hole. Problem arises.

  Then, an object of this invention is to provide the laser processing method, the laser processing apparatus, and laser processing program which solved the said subject.

The invention according to claim 1 irradiates a processing object placed on a gantry with a laser beam, and moves an irradiation position of the laser beam with respect to an arbitrary processing point of the processing object. In a laser processing method for drilling a shape,
While irradiating the laser beam to a preset processing point of the workpiece, the laser beam is moved along the contour shape of the hole, and the melted portion melted by the laser beam is moved into the cutting groove. A first processing step for processing to leave,
The laser beam is moved again along the contour shape of the hole in succession to the first machining step, and a melted portion left in the cutting groove by the first machining step is cut by the laser beam. Processing steps,
It is characterized by performing.

  The invention described in claim 2 is characterized in that the output of the laser beam in the first processing step is weaker than the output of the second processing step.

  The invention described in claim 3 is characterized in that the object to be processed is a metal mask used for screen printing.

The invention according to claim 4 irradiates the processing object placed on the gantry with laser light, and moves the irradiation position of the laser light to an arbitrary processing point of the processing object. In a laser processing device that drills a shape,
While irradiating the laser beam to a preset processing point of the workpiece, the laser beam is moved along the contour shape of the hole, and the melted portion melted by the laser beam is moved into the cutting groove. First processing means for processing to leave,
The laser beam is moved again along the contour shape of the hole continuously to the first processing means, and the melted portion left in the cutting groove is cut by the laser light by the first processing means. Processing means;
It is provided with.

  The invention described in claim 5 is characterized by comprising laser light output control means for setting the output of the laser light of the first processing means to be weaker than the output of the second processing means.

  A sixth aspect of the invention is characterized in that a computer executes the laser processing method according to any one of the first to third aspects.

  According to the present invention, the laser beam is moved along the contour shape of the hole while irradiating the processing portion of the processing object with the laser beam in the first processing step, and the melted portion melted by the laser beam is cut into the cutting groove. Next, the nozzle is moved again along the outline shape of the through hole in the second processing step, and the molten portion left in the cutting groove in the first processing step is cut with a laser beam. This prevents the oxidation product called dross from adhering to the back surface of the object to be processed, and the uncut portion (saw-toothed cut surface) that has been scraped off at the final cutting position for cutting the removed portion by laser processing. The hole processing accuracy can be increased by not leaving the hole on the inner peripheral surface.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a laser processing apparatus according to the present invention. In this embodiment, a case where a metal mask used for screen printing is laser processed will be described as an example.

  As shown in FIG. 1, a laser processing apparatus 10 includes a laser oscillator 12, a trepanning head 14, a processing nozzle 16, a work support unit 17, an XY table (base) 18, and an X-direction linear motor 20. And a Y-direction linear motor 22, a Z-axis drive unit 24, a stone surface plate 26, an assist gas emission device 27, and a control device 28.

  The control device 28 is composed of a microcomputer or the like, and drives and controls each operation unit such as the trepanning head 14, the work support unit 17, and the XY table 18 based on a control program stored in advance in the storage unit, and also the laser oscillator 12 The output level of the laser beam is controlled by controlling the voltage application to the laser beam.

  The laser beam generated by the laser oscillator 12 is irradiated to the metal mask material 30 clamped on the XY table 18 through the inside of the processing nozzle 16 via an optical system unit 31 including a mirror and a lens. Drilling is performed at an arbitrary processing position based on the processed data.

  Assist gas is supplied to the processing nozzle 16 from an assist gas emission device 27. And the process nozzle 16 is provided so that assist gas may be sprayed with respect to the process point of the metal sheet material 30 as a process target (work).

  The trepanning head 14 moves the machining nozzle 16 in the XY direction so as to drill a hole in the metal sheet material 30 placed on the XY table 18, and this nozzle movement trajectory has a contoured shape of the through hole. It becomes.

  The X-direction linear motor 20 and the Y-direction linear motor 22 can be set at a plurality of machining locations of the metal sheet material 30 at high speed and with high accuracy. Since the Z-axis drive unit 24 can move in the vertical direction, the machining nozzle 16 is moved up and down with respect to the metal sheet material 30 to adjust the imaging position of the laser beam. Each mechanism described above is installed on the stone surface plate 26 in a stable state.

FIG. 2 is a perspective view for explaining the internal configuration of the trepanning head 14.
As shown in FIG. 2, the trepanning head 14 is used for a base 32, a holder 34 that holds the machining nozzle 16, a displacement sensor 36 that detects the displacement of the holder 34, and a head that guides the holder 34 in the XY directions. An XY table 38, an X-direction motor 39 that drives the holder 34 in the X direction, and a Y-direction motor 40 that drives the holder 34 in the Y direction are included.

  The base 32 is held at the tip of the optical system unit 31, and the processing nozzle is driven by driving the holder 34 in the XY directions by the head X-direction motor 39 and the Y-direction motor 40 provided on the lower surface of the base 32. 16 is moved in the horizontal direction. For example, when a circular through hole is drilled by irradiating the metal sheet material 30 with a laser beam, the through hole having the radius is formed in the metal sheet material 30 by causing the processing nozzle 16 to move circularly with a predetermined radius. Can do.

FIG. 3 is a longitudinal sectional view showing the configuration of the machining nozzle 16 and the work support unit 17.
As shown in FIG. 3, the tip 16 a of the machining nozzle 16 formed in a conical shape is accommodated in the internal space 42 a of the upper work support 42. The work support unit 17 includes an upper work support 42 and a lower work support 44, and a lower work support 44 is provided below the upper work support 42 so as to face each other.

  The metal sheet material 30 is mounted between the upper work support 42 and the lower work support 44. Further, since the metal sheet material 30 is clamped on the XY table 18, when the processing point 46 is moved, an arbitrary processing point 46 is moved to the optical axis 47 of the laser beam, that is, the processing nozzle 16 by the XY table 18. Is moved in the XY directions so as to coincide with the axis O of the.

  The lower end of the upper work support 42 has a contact portion 42b that contacts the upper surface of the metal sheet material 30. A hollow portion 42c into which the machining nozzle 16 is inserted is vertically moved along the axis O at the center of the contact portion 42b. It penetrates in the direction.

  Further, the lower work support 44 is supported by the Z-axis moving mechanism 48 so as to be movable up and down. The lower work support 44 is raised during processing and presses the lower surface of the metal sheet material 30 to be sandwiched between the work support upper part 42. An upper portion of the lower work support 44 is provided with an abutting portion 44a that comes into contact with the lower surface of the metal sheet material 30. Inside the lower work support 44, metal powder scattered by processing and cut pieces (removed) A hollow portion 44b for collecting the portion) is provided. Further, on the outer periphery of the lower work support 44, together with the air in the hollow portion 44b, an exhaust pipe 50 for collecting the metal powder scattered by processing and the cut pieces (removed portion) in a collection unit (not shown). Is connected.

  When the drilling process for the processing point is completed, the lower work support 44 is lowered and separated from the metal sheet material 30, and the metal sheet material 30 is moved so that the next processing point faces the irradiation position (axis O) of the laser beam. Move horizontally.

FIG. 4 is a configuration diagram illustrating an example of a computer system of the control device 28.
As shown in FIG. 4, the computer system of the control device 28 includes an input device 52, an output device 54, a drive device 56, a recording medium 58, an auxiliary storage device 60, a memory device 62, and an arithmetic processing device. 64 are connected to each other by a bus B.

  The input device 52 includes a keyboard and a mouse that are operated by a user of the computer system. The output device 54 has a display (not shown) for displaying various windows and data necessary for operating the computer system.

  The recording medium 58 is set in the drive device 56, and various electronic data (such as drilling data) necessary for laser processing can be input to the control device 28. Further, the auxiliary storage device 60 accumulates input or set control information data. The memory device 62 includes a first machining process at each machining location of the workpiece input from the input device 52 by the user of the laser machining apparatus 10 and a second machining process performed continuously in the first machining process. Stores the control program in which is set. That is, the memory device 62 moves the nozzle along the contour shape of the hole while irradiating the laser beam emitted from the nozzle to the processing point of the processing target set in advance in the first processing step. A control program (first processing means) for processing so that the melted portion melted by light remains in the cutting groove, and the nozzle is moved again along the contour shape of the hole continuously after the first processing step, A control program (second processing means) for cutting the melted portion left in the cutting groove by the laser beam with the laser beam is stored.

  The arithmetic processing unit 64 creates a laser processing program based on the setting information stored in the memory device 62. And the arithmetic processing unit 64 controls the laser oscillator 12, the assist gas emission device 27, the trepanning head 14, and the XY table 18 by the created laser processing program, and controls the metal sheet material 30 that is the processing target. Drill holes.

Here, the procedure of the control process executed by the control device 28 will be described with reference to the flowchart shown in FIG.
As shown in FIG. 5, the control device 28 reads the XY coordinate data (Xn, Yn) of the machining point n from the memory device 62 in S11. In the next S12, the XY table 18 is driven to move the machining point n to the machining position.

  In S13, it is confirmed whether the XY coordinate data (Xn, Yn) of the processing point n coincides with the optical axis 47 of the laser beam (the axis O of the processing nozzle 16). In S13, when the XY coordinate data (Xn, Yn) of the processing point n does not coincide with the optical axis 47 of the laser beam (the axis O of the processing nozzle 16), the process returns to S12 and the XY table 18 is driven. When the machining point n coincides with the optical axis 47 of the laser beam, the process proceeds to S14, and the drilling data of the first machining process corresponding to the machining point n is read from the recording medium 58, and the machining necessary for the machining point n is performed. Data (laser processing position data corresponding to the hole shape, laser beam output, feed rate, etc.) is created.

  In S15, the machining data created in S14 is set. Subsequently, the process proceeds to S <b> 16, and the applied voltage to the laser oscillator 12 is controlled to irradiate the processing point n of the metal sheet material 30 with the laser beam. In S17, the XY table 18 of the trepanning head 14 is driven to move the machining nozzle 16 in the XY direction. The movement trajectory of the machining nozzle 16 in the X and Y directions coincides with a preset hole shape, and arbitrary drilling is performed on the machining point n of the metal sheet material 30.

  In S18, it is confirmed whether or not the first processing step is completed. For example, when processing a hole having a circular contour, laser light is emitted at the processing start position, and the laser light is moved in a circular shape along the contour of the hole. Then, the laser beam irradiation position moves from the processing start position so as to have a predetermined radius of curvature. When the laser light makes a round along the contour of the hole to be processed, the laser beam returns to the irradiation start position again. The machining process ends.

  In S18, when the first processing step is not completed, the process returns to S15, and the processes of S15 to S18 are repeated. In S18, when the first machining process for the machining point n is completed, the process proceeds to the second machining process. That is, in the first drilling process, when the laser light makes a round along a preset hole-shaped contour, the nozzle movement locus becomes the contour shape of the drilling process.

  In this first processing step, the output of the laser beam is set to be weaker than the normal output level, so the removed portion is not completely cut and the molten portion remains in the cut groove. And the cutting groove will be in the state welded by the fusion | melting part.

  In S19, the drilling data of the second machining process corresponding to the machining point n is read from the recording medium 58, and machining data necessary for the machining point n (laser machining position data corresponding to the hole shape, laser beam output, feed rate, etc.) ).

  In S20, the machining data created in S19 is set. Note that when the machining data in the second machining process is set to be the same as the machining data in the first machining process, the processes of S19 and S20 may be omitted.

  Subsequently, the process proceeds to S <b> 21, and the applied voltage to the laser oscillator 12 is controlled to irradiate the processing point n of the metal sheet material 30 with the laser beam. In S22, the XY table 18 of the trepanning head 14 is driven to move the machining nozzle 16 in the XY direction. The movement trajectory of the machining nozzle 16 in the XY direction coincides with the movement trajectory of the first machining step, and an arbitrary drilling process is performed on the machining point n of the metal sheet material 30.

  In the second processing step, the output of the laser beam is set to a normal output level, and the melted portion left in the cutting groove remaining in the first processing step is melted and removed by the second laser beam. The

  In S23, it is confirmed whether or not the second processing step is completed. In S23, when the 2nd processing process is not complete | finished, it returns to said S20 and repeats the process of S20-S23. In S23, when the second machining step for the machining point n is completed, the process proceeds to S24, and it is confirmed whether or not the drilling machining for all set machining points is completed.

  If a machining point that has not been machined still remains in S24, the process proceeds to S25, 1 is added to the counter value n, the process returns to S11, and the processes of S11 to S24 are repeated. In S24, when the drilling for all the machining points is completed, the process proceeds to S26, the workpiece replacement is displayed, and the current process is terminated.

Here, the processing state of the first processing step will be described with reference to FIGS. 6 and 7.
6A and 6B are diagrams showing a processing state of the first processing step, where FIG. 6A is a longitudinal sectional view viewed from a direction orthogonal to the moving direction of the laser beam, and FIG. 6B is a longitudinal sectional view viewed from the moving direction of the laser beam. is there. (A) and (B) are figures which show the processing state of the 1st processing process. 7A and 7B are diagrams showing the processing state of the first processing step, where FIG. 7A shows a laser light irradiation surface (front surface), and FIG. 7B shows a back surface.

  In this first processing step, for example, when circular drilling is performed, as shown in FIGS. 6A and 6B, the output of the laser beam is set to be weaker than the normal output level. The removal portion 78 is not completely cut. The melted portion 70 melted by the laser light has a curved shape with respect to the direction orthogonal to the moving direction of the processing nozzle 16, and a part of the melted portion 70 scatters below the cutting groove 72, and the hollow portion 44 b of the lower work support 44. It is recovered through.

  The laser beam output in the first processing step is set to be weaker than the normal output level using parameters such as the thickness, material, and feed rate of the metal sheet material 30 as parameters, and a part of the melted portion 70 is It is set so as to remain in the cutting groove 72. Therefore, when the processing point n is viewed from the laser light irradiation side (front side), a continuous circular groove 74 is formed as shown in FIG. However, when the processing point n is viewed from the back side through which the laser beam passes, as shown in FIG. 7B, the melted portion 70 protrudes intermittently and an intermittent groove 76 is formed.

  In addition, the melted portions 70 are partially scattered in the cut grooves 72 after the laser beam passes, and the cut grooves 72 are fixed by being gradually cooled. Therefore, even if the first processing step is completed, the removed portion 78 located inside the circular shape is welded to the metal sheet material 30 by the molten portion 70 solidified without falling.

Next, the processing state of the second processing step will be described with reference to FIGS.
8A and 8B are diagrams showing a processing state in the second processing step, where FIG. 8A is a longitudinal sectional view as seen from a direction orthogonal to the moving direction of the laser beam, and FIG. 8B is a longitudinal sectional view as seen from the moving direction of the laser beam. is there. 9A and 9B are diagrams showing the processing state of the second processing step, where FIG. 9A shows the laser light irradiation surface (front surface), and FIG. 9B shows the back surface.

  In the second processing step, the output of the laser beam is set to a normal output level, and the melted portion 70 remaining in the first processing step is caused by the laser beam as shown in FIGS. 8A and 8B. It melts and scatters into the hollow part 44 b of the lower work support 44. Since the melted portion 70 remains only intermittently, most of the melted portion 70 is heated to a molten state and scattered below the cutting groove 72 when irradiated with laser light.

  Therefore, when the processing point n is viewed from the laser light irradiation side (front side), as shown in FIG. 9A, a continuous circular groove 74 is formed. As shown in B), a circular groove 80 is formed. Therefore, when the second machining step is completed, the removal portion 78 located inside the circular grooves 74 and 80 is cleanly cut and the drilling process is completed.

  As described above, by irradiating the laser beam twice and cutting in stages, the dross on the back surface side can be reduced, and the final cutting groove in the cutting groove 72 is cut off as in the prior art. This prevents the cutting from being left on the inner periphery of the hole (a jagged cut surface), and the processing accuracy of the cutting groove 72 can be further increased. Thereby, since the metal sheet obtained by drilling a large number of holes in the metal sheet material 30 has a high processing accuracy of each hole, the printing accuracy when the solder paste is printed by screen printing becomes higher. .

  In the above-described embodiment, the case of drilling a metal sheet used for screen printing is given as an example. However, the present invention is not limited to this, and can be applied to drilling other workpieces (workpieces). Of course.

  In the above embodiment, the case of processing a circular hole is given as an example. However, the present invention is not limited to this, and the present invention can be applied to processing holes of other shapes (for example, a square, a triangle, etc.). Of course.

It is a block diagram which shows one Example of the laser processing apparatus which becomes this invention. 4 is a perspective view for explaining an internal configuration of a trepanning head 14. FIG. FIG. 3 is a longitudinal sectional view showing configurations of a processing nozzle 16 and a work support unit 17. 3 is a configuration diagram illustrating an example of a computer system of a control device 28. FIG. It is a flowchart for demonstrating the procedure of the control processing which the control apparatus 28 performs. It is a figure which shows the process state of a 1st process process, (A) is a longitudinal cross-sectional view seen from the direction orthogonal to the moving direction of a laser beam, (B) is a longitudinal cross-sectional view seen from the moving direction of a laser beam. It is a figure which shows the process state of a 1st process process, (A) is a laser beam irradiation surface (front surface), (B) is a figure which shows a back surface. It is a figure which shows the processing state of a 2nd process process, (A) is a longitudinal cross-sectional view seen from the direction orthogonal to the moving direction of a laser beam, (B) is a longitudinal cross-sectional view seen from the moving direction of a laser beam. It is a figure which shows the process state of a 2nd process process, (A) is a laser beam irradiation surface (front surface), (B) is a figure which shows a back surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 12 Laser oscillator 14 Trepanning head 16 Processing nozzle 17 Work support part 18 XY table 27 Assist gas ejection apparatus 28 Control apparatus 30 Metal sheet material 38 XY table 42 for heads Upper work support 44 Lower work support 46 Processing point 56 Drive device 58 Recording medium 62 Memory device 64 Arithmetic processing device 70 Melting portion 72 Cutting groove 74, 80 Circular groove 76 Intermittent groove 78 Removal portion

Claims (6)

Laser processing that irradiates a laser beam to a processing object placed on a gantry and moves the irradiation position of the laser beam to an arbitrary processing point of the processing object to perform drilling processing of an arbitrary shape In the method
While irradiating the laser beam to a preset processing point of the workpiece, the laser beam is moved along the contour shape of the hole, and the melted portion melted by the laser beam is moved into the cutting groove. A first processing step for processing to leave,
The laser beam is moved again along the contour shape of the hole in succession to the first machining step, and a melted portion left in the cutting groove by the first machining step is cut by the laser beam. Processing steps,
The laser processing method characterized by performing.   2. The laser processing method according to claim 1, wherein the output of the laser beam in the first processing step is weaker than the output of the second processing step.   The laser processing method according to claim 1, wherein the processing object is a metal mask used for screen printing. Laser processing that irradiates a laser beam to a processing object placed on a gantry and moves the irradiation position of the laser beam to an arbitrary processing point of the processing object to perform drilling processing of an arbitrary shape In the device
While irradiating the laser beam to a preset processing point of the workpiece, the laser beam is moved along the contour shape of the hole, and the melted portion melted by the laser beam is moved into the cutting groove. First processing means for processing to leave,
The laser beam is moved again along the contour shape of the hole continuously to the first processing means, and the melted portion left in the cutting groove is cut by the laser light by the first processing means. Processing means;
A laser processing apparatus comprising:   6. The laser processing apparatus according to claim 5, further comprising laser light output control means for setting the output of the laser light of the first processing means to be weaker than the output of the second processing means. A laser processing program for causing a computer to execute the laser processing method according to claim 1.

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