WO2024161490A1 - Laser machining device, laser machining method, and program - Google Patents

Abstract

Provided is a laser machining device comprising: a light guide unit that guides laser emitted from a light source to a machining surface of a workpiece; and a control unit that controls a displacement by each of an optical path displacement unit and an object displacement unit, the optical path displacement unit displacing an optical path of the laser guided by the light guide unit about the axis of a virtual cone along a conical surface thereof, the virtual cone having the optical axis of the optical path as the generatrix and a position that is on the optical axis and overlaps the machining surface as the vertex, the object displacement unit displacing the workpiece along an object plane that intersects with the axis of the virtual cone. The control unit forms the machining surface on the workpiece by simultaneously performing object control and optical path control, the object control causing the object displacement unit to displace the workpiece at a predetermined object angular velocity from an object start position along the circumference of a virtual circle, which is drawn so as to have the vertex of the virtual cone as the center and the same radius as an object arc, until an object end position is reached, the optical path control causing the optical path displacement unit to displace the optical path of the laser about the axis of the virtual cone at an optical angular velocity, which is the same as the object angular velocity, from an optical path start position until an optical path end position is reached.

Description

Laser processing device, laser processing method, and program

The present invention relates to a laser processing device that performs processing using a laser.

In recent years, a technology has been proposed in which a cylindrical irradiation area extending in the direction of the laser's optical axis is displaced in a direction intersecting the optical axis to form a machined surface on the surface side of the workpiece through which the irradiation area passes (Patent Document 1). This processing method is superior to mechanical processing methods in that it reduces mechanical damage and forms a smooth machined surface.

Patent No. 6562536

This type of processing method is also used in applications such as regenerating corners in workpieces that have corners formed by two adjacent end faces, such as cutting tools that have corners formed by the rake face and flank face. Specifically, a laser is irradiated so that the optical axis extends along the direction in which the rake face or flank face widens, and a new rake face or flank face can be formed at the corner by displacing the laser.

However, there are some workpieces for which laser processing is not necessarily practical. For example, a ball end mill is used to cut a truncated cone around its axis at a certain angle, forming a corner between the truncated cone surface and the base. At this corner, one of the surfaces (the relief surface) forms a complex curved shape that follows the truncated cone surface.

In this way, when the corners have surfaces with complex curved shapes, the optical axis of the laser and the workpiece cannot be displaced in a complex manner to form a suitable machined surface, which requires multi-axis machining, making the device configuration and control significantly more complex. For these reasons, there has been an issue that laser machining is not necessarily practical for machined surfaces with complex curved shapes.

The present disclosure has been made to solve these problems, and its purpose is to make it possible to perform laser processing even on surfaces with complex curved shapes while minimizing the complexity of the device configuration and control.

In order to solve the above problem, the first aspect of the present invention comprises a light guiding section that guides a laser irradiated from a light source to a processing surface of a workpiece, a light path displacement section that displaces the light path of the laser guided to the light guiding section about the axis of a virtual cone whose optical axis serves as a generating line and whose apex is a position on the optical axis that overlaps with the processing surface, and a control section that controls the displacement by the object displacement section that displaces the workpiece along an object plane that intersects with the axis of the virtual cone, and in the case where a cone frustum surface having a shape obtained by cutting a virtual truncated cone whose bottom surface extends along the object plane by a predetermined angle range about its axis, the control section displaces the virtual truncated cone surface from an object start position on the object plane where one end of an object arc formed by the processing surface around the bottom surface of the virtual truncated cone is the apex of the virtual cone, This laser processing device simultaneously performs object control, which causes the object displacement section to displace the object to be processed at a predetermined object angular velocity along the circumference of a virtual circle drawn with the same radius as the object arc, centered on the apex of the imaginary cone, until the other end of the object arc reaches an object end position where it overlaps with the apex of the virtual cone, and optical path control, which causes the optical path displacement section to displace the optical path of the laser at the same optical path angular velocity as the object angular velocity, from an optical path start position along the direction of extension of a line segment connecting the center of the object arc at the object start position and the apex of the virtual cone, around the axis of the virtual cone, until it reaches an optical path end position along the direction of extension of a line segment connecting the center of the object arc at the object end position and the apex of the virtual cone, in the object plan view, to form the processed surface by laser on the object to be processed.

In addition, in this aspect, the second aspect described below may be adopted.
In a second aspect, the control unit causes the optical path displacement unit to displace the optical path of the laser such that a position on the optical axis that overlaps with a boundary ridge between a truncated cone surface and a top surface of the virtual truncated cone becomes the apex of the virtual cone.

In addition, in each of the above aspects, the third aspect described below may be adopted.
In a third aspect, the light guiding unit includes a pair of wedge plates arranged coaxially with the axis of a cylindrical region through which a laser irradiated from a light source passes and spaced apart in the axial direction, a lens arranged coaxially with the axis of the cylindrical region downstream of the wedge plates in the optical path of the laser and refracting the laser after passing through the wedge plate toward the processing surface, and a rotation mechanism rotating the wedge plate around the axis of the cylindrical region to scan the laser after passing through the wedge plate in a circumferential direction, and the optical path displacement unit displaces the optical path of the laser guided to the light guiding unit along the conical surface of the virtual cone by rotating the wedge plate with the rotation mechanism.

In the laser processing device of the above aspect, the optical path of the laser is displaced along the conical surface of the imaginary cone, while the workpiece is displaced along the circumference of the imaginary circle. As a result, the laser is relatively displaced around the axis on the frustum surface of the imaginary frustum of the cone in the workpiece, while being aligned with the generatrix of the imaginary frustum of the cone, so that a machined surface that follows the frustum surface of the imaginary frustum is formed on the workpiece. In this way, the end face of a complex curved shape such as a frustum surface of a cone can be formed as the machined surface.

Here, the relative displacement of the laser with respect to the workpiece can be achieved by two-axis control of the optical path displacement section and the object displacement section, so even when the workpiece surface has a complex curved shape, laser processing can be achieved without requiring more multi-axis and complex control.

FIG. 1 is a block diagram showing a configuration of a laser processing apparatus according to an embodiment of the present disclosure. FIG. 1 is a front view showing a tip shape of an object to be processed in an embodiment of the present disclosure; FIG. 1 is a cross-sectional view showing a configuration of a light guide unit according to an embodiment of the present disclosure; 1A and 1B are a front view and a right side view, respectively, illustrating a state in which an object to be processed and a laser optical path are displaced in an embodiment of the present disclosure; A flowchart showing a processing procedure of a processing process according to an embodiment of the present disclosure. FIG. 1 is a front view illustrating a state in which the optical path of the laser and the workpiece are displaced in an embodiment of the present disclosure;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in
(1) Overall structure

As shown in FIG. 1, the laser processing device 1 includes a light source 10 that outputs a laser, a holding unit 20 that holds the workpiece 100, a light guiding unit 30 that guides the laser irradiated from the light source 10 to the processing surface 111 of the workpiece 100, an optical path displacement unit 40 that displaces the optical path of the laser guided to the light guiding unit 30, an object displacement unit 50 that displaces the workpiece 100, and a control unit 60 that controls the operation of the entire laser processing device 1.

In this embodiment, the workpiece 100 is a ball end mill with multiple corners 110 formed on the tip side (the lower end side in this embodiment) of a rod-like member, as shown in Figure 2. Each corner 110 is a blade made up of a truncated cone surface and a bottom surface in a shape obtained by cutting a virtual truncated cone around the axis by a predetermined angle range (specifically, a range of 90 degrees), and one surface (the relief surface) has a curved shape that follows the truncated cone surface.

The light source 10 is equipped with a laser oscillator that outputs a pulsed laser, a vibration regulator that adjusts the order of the laser's vibration frequency, an attenuator that adjusts the laser output, a beam expander that adjusts the diameter of the laser, and other components, and is configured so that the laser that has passed through these components is output via an optical lens. Of these, an Nd:YAG pulsed laser is used for the laser oscillator.

The holding part 20 holds the workpiece 100 with its tip positioned downward and the other surface (scooping surface) at the corner oriented along the target plane described below.

As shown in FIG. 3, the light guide 30 includes a cylindrical main body 31 that surrounds a cylindrical region through which the laser irradiated from the light source 10 passes, a pair of wedge plates 35 and 37 that are arranged coaxially with the axis 33 of the main body 31 within the cylindrical region and spaced apart in the direction of the axis 33, and a lens 39 that is arranged further downstream in the optical path than the wedge plate 37 on the downstream side of the optical path.

Of these, the wedge plates 35 and 37 are configured so that the wedge plate 37 on the downstream side of the optical path can be displaced to any position along the axis 33 (see the arrow in the figure), and this allows the spacing between the pair of wedge plates 35 and 37 to be changed as desired. In this embodiment, the wider the spacing between the pair of wedge plates 35 and 37, the farther radially from the axis 33 the position where the laser passes through becomes.

The lens 39 is an optical lens that is arranged coaxially with the axis 33 of the main body 31 and refracts the laser that has passed through the wedge plates 35 and 37 toward the processing surface 111 of the workpiece 100.

The optical path displacement unit 40 is an actuator that rotates the main body unit 31 around the axis 33 upon receiving a command from the control unit 60, and in conjunction with this rotation, it rotates the wedge plates 35 and 37 arranged within the main body unit 31 around the axis 33.

Here, rotating the wedge plates 35, 37 means that the laser that has passed through the wedge plates 35, 37 is scanned in the circumferential direction on a plane that intersects with the optical axis. In this way, the laser that has passed through the wedge plates 35, 37 passes further through the lens 39, where it is refracted at an angle that corresponds to the radial position relative to the axis 33 of the optical axis.

As a result, as shown in FIG. 4, the laser is displaced around its axis 230 along the conical surface 220 of a virtual cone 200 whose generating line is the optical axis and whose apex 210 is a position on the optical axis where it overlaps with the processing surface 111 (see arrow a in the same figure).

The object displacement unit 50 is an actuator that displaces the holding unit 20 along an object plane (see FIG. 4(a)) perpendicular to the axis 230 of the virtual cone 200, and displaces the workpiece 100 held by the holding unit 20.

(2) Processing by the control unit 60 Next, the processing executed by the control unit 60 according to a program stored in the built-in memory 61 will be described with reference to Fig. 5. This processing is started when a start command is received from an interface (operation device or communication device) not shown.

In this embodiment, as shown in FIG. 2, one surface (flank) forming a corner 110 of the workpiece 100, i.e., a curved shape that follows the frustum surface of the imaginary frustum of a cone, is formed as the machining surface 111.

When this processing is started, first, the workpiece 100 is positioned at the target start position 100s (s110). As shown in FIG. 6, the target start position 100s is a position on the target plane that intersects with the axis 230 of the virtual cone 200, where one end 113 of the target arc that the processing surface 111 forms around the bottom surface of the virtual truncated cone is the apex 210 of the virtual cone 200. Here, the position where the optical axis of the laser overlaps with the boundary ridge between the truncated cone surface and the top surface of the virtual truncated cone is set as the apex 210 of the virtual cone 200 (see FIG. 3(b)), and subsequent processing is performed based on this setting.

Next, object control to displace the workpiece 100 and optical path control to displace the optical path of the laser are started simultaneously (s120).

As shown in FIG. 6, the target control is a control for displacing the workpiece 100 from the target start position 100s until it reaches the target end position 100e, and is performed by a command to the target displacement unit 50. Here, the target end position 100e is the position on the target plane where the other end 115 of the target arc overlaps with the apex 210 of the virtual cone 200.

Then, the target displacement unit 50 is controlled so that the target start position 100s and the target end position 100e are displaced at a predetermined target angular velocity along the circumference of a virtual circle 120 that is drawn with the same radius as the target arc and centered on the apex 210 of the virtual cone 200 (see arrow b in the figure).

On the other hand, optical path control is a control for displacing the optical path of the laser from the optical path start position 300s until it reaches the optical path end position 300e, and is performed by a command to the optical path displacement unit 40. Here, the optical path start position 300s is a position where the optical axis of the laser is along the extension direction of the line segment connecting the center 117 of the target arc at the target start position 100s and the apex 210 of the virtual cone 200, as shown in FIG. 6. Also, the optical path end position 300e is a position where the optical axis of the laser is along the extension direction of the line segment connecting the center 117 of the target arc at the target end position 100e and the apex 210 of the virtual cone 200.

Then, the optical path displacement unit 40 is controlled so that the optical path is displaced around the axis 230 of the virtual cone 200 at the same optical path angular velocity as the target angular velocity between the optical path start position 300s and the optical path end position 300e.

After the object control and light path control are started, the system waits until these controls are completed (s130: NO), and when they are completed (s130: YES), the processing process ends. By simultaneously executing the object control and light path control in this way, the processing surface 111 is formed on the workpiece 100 by the laser.

(3) Modifications Although the embodiments of the present invention have been described above, it goes without saying that the present invention is in no way limited to the above-described embodiments, and various modifications can be made as long as they fall within the technical scope of the present invention.

For example, in the above embodiment, the light guide unit 30 is configured by a pair of wedge plates 35, 37 and a lens 39. However, the light guide unit 30 is not limited to the above configuration as long as it can displace the optical path of the laser around the axis 230 along the conical surface 220 of the virtual cone 200.

In addition, in the above embodiment, the laser processing device 1 is equipped with each of the components, but the laser processing device 1 may also be realized by, for example, mounting the light source 10, the light guide unit 30, and the control unit 60 (or a program for causing the control unit of the machine tool to execute the processing) on a general-purpose machine tool equipped with the holding unit 20 and actuators corresponding to the light path displacement unit 40 and the target displacement unit 50.

In the above embodiment, the position where the optical axis of the laser overlaps with the boundary ridge between the truncated cone surface and the top surface of the virtual truncated cone is set as the apex 210 of the virtual cone 200. However, the apex 210 of the virtual cone 200 may be set at another position (for example, the upstream end of the optical path) in the range from the upstream end of the optical path to the downstream end of the optical path on the processing surface 111.

(4) Effects In the laser processing device 1 according to the above embodiment, the optical path of the laser is displaced along the conical surface 220 of the virtual cone 200, while displacing the workpiece 100 along the circumference of the virtual circle 120. As a result, the laser is relatively displaced around the axis on the frustum surface of the virtual frustum of the workpiece 100 while being aligned along the generatrix of the virtual frustum of the cone, so that a processing surface 111 along the frustum surface of the virtual frustum of the cone is formed on the workpiece 100. In this way, an end face of a complex curved shape such as a frustum surface of a cone can be formed as the processing surface 111.

Here, the relative displacement of the laser with respect to the workpiece 100 can be achieved by two-axis control of the optical path displacement unit 40 and the object displacement unit 50, so even if the workpiece surface 111 has a complex curved shape, laser processing can be achieved without requiring further multi-axis control.

In addition, in the laser processing device 1 of the above embodiment, the laser after passing through the wedge plates 35, 37 is refracted by the lens 39 toward the processing surface 111, so that the laser from the light source 10 can be scanned in the circumferential direction by rotating the wedge plates 35, 37, thereby displacing the optical path of the laser around the axis 230 along the conical surface 220 of the virtual cone 200.

In addition, in the above embodiment, if the laser processing device 1 is realized by mounting the light source 10, the light guide unit 30, and the control unit 60 on a general-purpose machine tool, the laser processing device 1 of the above embodiment can be realized at low cost by simply mounting some of the components on the general-purpose machine tool.

The laser processing device disclosed herein can perform laser processing even on surfaces with complex curved shapes while minimizing the complexity of the device configuration and control.

1...laser processing device, 10...light source, 20...holding section, 30...light guide section, 31...main body section, 33...axis, 35...wedge plate, 37...wedge plate, 39...lens, 40...light path displacement section, 50...target displacement section, 60...control section, 61...built-in memory, 100...processing target, 100e...target end position, 100s...target start position, 110...corner, 111...processing surface, 113...one end, 115...other end, 117...center, 120...virtual circle, 200...virtual cone, 210...apex, 220...cone surface, 230...axis, 300e...light path end position, 300s...light path start position.

Claims (5)

a light guide unit that guides a laser irradiated from a light source to a processing surface of an object to be processed;
a control unit that controls the displacement by a light path displacement unit that displaces the light path of the laser guided to the light guiding unit around the axis of a virtual cone surface having an optical axis as a generating line and an apex at a position on the optical axis that overlaps with the processing surface, and an object displacement unit that displaces the processing object along an object plane that intersects with the axis of the virtual cone,
In the case where a frustum surface having a shape obtained by cutting a virtual frustum of a cone whose bottom surface spreads along the target plane by a predetermined angle range around its axis is formed as the processed surface,
The control unit is
a target control that displaces the object to be machined at a predetermined target angular velocity by the target displacement section on the target plane from a target start position where one end of the target arc formed by the machining surface around the bottom surface of the virtual truncated cone becomes the apex of the virtual cone along a circumference of a virtual circle drawn with the same radius as the target arc and centered on the apex of the virtual cone, until the other end of the target arc overlaps with the apex of the virtual cone;
an optical path control that causes the optical path displacement unit to displace the optical path of the laser at an optical path angular velocity equal to the target angular velocity, from an optical path start position along an extension direction of a line segment connecting the center of the target arc at the target start position and the apex of the virtual cone, around an axis of the virtual cone, until the optical axis of the laser reaches an optical path end position along an extension direction of a line segment connecting the center of the target arc at the target end position and the apex of the virtual cone, in the target planar view;
and forming the laser processed surface on the workpiece by simultaneously carrying out the steps.
Laser processing equipment. the control unit causes the optical path displacement unit to displace the optical path of the laser, with a position on the optical axis that overlaps with a boundary ridge between a truncated cone surface and a top surface of the virtual truncated cone being set as a vertex of the virtual cone.
The laser processing device according to claim 1. The light guide unit includes a pair of wedge plates arranged coaxially with the axis of the cylindrical region and spaced apart in the axial direction within a cylindrical region through which a laser irradiated from a light source passes, a lens arranged coaxially with the axis of the cylindrical region downstream of the wedge plates in the optical path of the laser, and refracting the laser after passing through the wedge plate toward the processing surface, and a rotation mechanism that rotates the wedge plate around the axis of the cylindrical region to scan the laser after passing through the wedge plate in a circumferential direction,
The optical path displacement unit displaces an optical path of the laser guided to the light guiding unit along a conical surface of the virtual cone by rotating the wedge plate with the rotation mechanism.
The laser processing device according to claim 1. a light guide unit that guides a laser irradiated from a light source to a processing surface of an object to be processed;
an optical path displacement unit that displaces the optical path of the laser guided to the light guide unit about its axis along a conical surface of a virtual cone whose apex is a position on the optical axis that overlaps with the processing surface, the virtual cone having an optical axis as a generating line;
an object displacement unit that displaces the object along an object plane that intersects with an axis of the virtual cone;
A laser processing method for forming the processed surface on the object to be processed by a laser processing apparatus comprising:
In the case where a frustum surface having a shape obtained by cutting a virtual frustum of a cone whose bottom surface spreads along the target plane over a predetermined angle range around its axis line is formed as the processed surface,
a target control that displaces the object to be machined at a predetermined target angular velocity by the target displacement section on the target plane from a target start position where one end of the target arc formed by the machining surface around the bottom surface of the virtual truncated cone becomes the apex of the virtual cone along a circumference of a virtual circle drawn with the same radius as the target arc and centered on the apex of the virtual cone, until the other end of the target arc overlaps with the apex of the virtual cone;
and simultaneously performing an optical path control in which the optical path displacement unit displaces the optical path of the laser at an optical path angular velocity equal to the target angular velocity, from an optical path start position along the extension direction of a line segment connecting the center of the target arc at the target start position and the apex of the virtual cone, around the axis of the virtual cone, until the optical axis of the laser reaches an optical path end position along the extension direction of a line segment connecting the center of the target arc at the target end position and the apex of the virtual cone, in the target planar view.
Laser processing method. A program for causing a computer to function as the control unit described in claim 1.

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