JP2008200712A - Method and apparatus for laser beam machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the generation of a moving path and the movement along the moving path, by which moving path, the shapes or their combinations in a laser beam cutting-off operation for cutting off a round hole, an elongated hole, a square hole, a corner loop portion, a micro joint portion, and a profile shape, etc. can be quickly and accurately cut off while avoiding mechanical shocks. <P>SOLUTION: An accelerating section 104 is provided expediently between a moving path section 102, in which the laser beam machining is not carried out, and a cutting-off path section 106, in which the laser beam machining is carried out. The accelerating section 104 is set such that the absolute values of the respective acceleration and the respective jerk in the cutting-off path section 106 is limited within an allowable value in both of the tangential direction and the normal direction of the path. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention condenses laser light and irradiates the workpiece, moves the processing head relative to the workpiece, scans the focal point on the workpiece, and performs cutting, welding, and marking. In particular, a technique for performing laser processing with a shape on a scanning locus by scanning a condensing point along a path such as an arc, an ellipse, or a line segment, etc. About.

  There are several types of laser processing apparatuses that perform laser cutting, laser welding, and laser marking. For example, the shape of the laser irradiation area on the workpiece is generated by the optical system and processing is performed according to the irradiation pattern, or the surface of the workpiece is scanned by a pulsed laser with an optical system using a galvanometer mirror Some of them perform shape processing. On the other hand, as a method employed in many laser processing apparatuses, there is a method in which laser processing is sequentially performed by condensing a laser beam on a workpiece and scanning the condensing point.

  A laser processing apparatus that scans a condensing point generally includes a numerical control device, and performs scanning by relatively moving the condensing point and the workpiece by a servo motor. The laser beam is guided from a laser oscillator to a laser processing head having a condensing optical system using an optical fiber or a reflecting mirror, and is irradiated to a condensing point together with an assist gas or a shield gas.

  The drive by the servo motor is required to have at least an XY two-axis configuration, but in most cases, a three-axis configuration including the Z axis is used to retract the processing head away from the workpiece. Further, in order to irradiate a three-dimensional workpiece with a laser beam from a desired direction, a plurality of drive shafts may be provided.

  In such a laser processing apparatus, the numerical control apparatus normally decodes an operation program based on the NC program or the teaching playback method, and outputs a movement command to the servo motor. Regardless of the program form, the program is mainly composed of movement command units called blocks or “command lines”. This block or “command line” is sequentially executed, and the movement command unit is executed in the form of a movement command from the current point to the destination. Further, the unit for moving to the destination includes means for specifying the moving route. As a movement path, there are a case where a shape such as a line segment (straight line), an arc or a circle is designated, and a case where a movement of each axis is designated. In the latter case, there are a case where each axis operates independently based on a designated speed, and a case where each axis is driven with its axis speed controlled so that the operation ends simultaneously when reaching the end point. . In addition, when designating a shape, it may be commanded over two blocks, but in this case as well, it can be considered as one shape as an operation command.

  On the other hand, individual shapes that are actually used as machining shapes in laser machining are overwhelmingly often designated as line segments, arcs, or circles, and rarely are designated as ellipses or spline curves. Therefore, most laser processing is performed by moving a locus obtained by combining a large number of three types of shapes, ie, line segments, arcs, and circles.

  For example, in the cutting process of sheet metal, the outline shape of a round hole, a long hole, a square hole, and an outer peripheral portion is described using the above three types of shapes, and the stroke of the workpiece is drawn in the manner of a stroke. It will be cut off. However, when a certain machining shape is separated from another machining shape, laser irradiation is temporarily stopped and the laser machining head is moved. In this case, the servo shaft is driven regardless of the above three types of shapes, but usually linear driving is often performed. An example of an actual NC program is shown below with a brief description of each line.

G00 X50. Y45.; Move to the point where laser processing starts and stop
G01 X50. Y50. R5. S1000 F8000; Laser machining with line segment to the point of (50,50)
G02 J-10.; Laser machining of perfect circle centered on Y coordinate -10 from current point
G00 X95. Y45; Move to the next laser processing start point (95,45) without laser irradiation

  In the current mainstream laser processing equipment, laser processing is basically performed by first stopping the processing head at the laser processing start point, then starting laser irradiation, and moving the processing head almost simultaneously with that to perform laser processing. After finishing the shape, the cycle of stopping the processing head and stopping the laser irradiation is repeated. In this method, the servo axis always stops temporarily at the start point and end point of a series of machining shapes. Therefore, for example, in Patent Document 1, when performing laser processing of a large number of shapes, the acceleration / deceleration time of the conventional processing method is shortened by turning on and off the laser beam while moving the servo axis without stopping the processing head. A laser processing apparatus is disclosed.

  On the other hand, laser processing has a problem that occurs because it is thermal processing. In the corner part of the trajectory, the machining speed must be reduced in order to obtain a precise trajectory shape. In such a case, if machining is performed with a constant laser output, the part that is moving at a low speed is covered. The amount of heat given to the workpiece increases, and a certain laser processing result may not be obtained. One method for avoiding this is corner loop machining. Since corner loop machining is often performed without stopping the movement of the machining head, this is also a type of laser machining that does not stop the machining head. There is a prior proposal for optimization of the locus of the corner loop (Patent Document 2).

  By connecting a series of laser processing head movements along a smooth path, the laser processing time can be shortened. For example, in Patent Document 2, the corner loop shape, which has been a simple arc in the past, is replaced with a shape in which two parabolas and a quarter arc are combined to shorten the machining time. However, if the commanded trajectory touches geometrically smoothly at the start point and end point of the command unit, the device cannot be operated smoothly. For example, as shown in FIG. 16 (a), when machining a sharp corner, even if the straight lines l1 and l2 and the arc c1 are machining paths that smoothly connect to each other at points t1 and t2, respectively, t1 and At t2, the acceleration in the normal direction of the arc suddenly changes, and the trajectory accuracy deteriorates due to a mechanical shock. This is the same when laser processing is performed by moving between the parts to be processed. For example, as shown in FIG. 16B, a plurality of (two in the illustrated example) round holes c2 and c3. When the cutting process is performed, the shortest movement path between the round holes is a line segment l3 indicated by a broken line, but the laser processing apparatus receives a large mechanical shock at the connection point t3 between l3 and the circle c3. Therefore, the shape accuracy of the round hole cannot be maintained. Therefore, there are proposals for processing with such a time change of acceleration, that is, the jerk is suppressed (Patent Document 3), and when the jerk is increased, a proposal for suppressing the acceleration is reduced (Patent Document 4). is there.

  From such a background, what kind of locus path is generated becomes a problem whether laser processing can be performed at high speed while maintaining shape accuracy. With respect to this problem, there are a proposal for generating a path for cutting off many round holes in laser cutting (Patent Document 5) and a proposal for generating a path for cutting a square hole (Patent Document 6). On the other hand, in a general machine tool, there is a proposal to smoothly connect and superimpose movement command values on path sections that follow each other of path paths that are not smoothly connected (see, for example, Patent Document 7). ).

JP-A-7-232288 JP 2004-9054 A JP-A-9-99384 JP-A-9-101814 Japanese Patent Laid-Open No. 8-1108048 JP-A-10-249563 JP 10-63329 A

  In the case of laser cutting, when the object to be processed is an extremely thin plate-like material having a thickness of 1 mm or less, for example, good laser cutting can be started without performing drilling processing before laser cutting, that is, so-called piercing processing. Is possible. On the other hand, in the case of a material having a thickness greater than that, the cutting result at the cutting start point is generally not good unless piercing is performed first. However, in laser cutting, one side of the cutting line is often cut off and unnecessary, so piercing is first performed on this unnecessary part, and drilling is performed while moving the processing head. Laser cutting with poor cutting results Since the starting part is eventually discarded, it can be said that there is no problem in the cutting result. Therefore, if laser cutting is started from an unnecessary portion in this way, laser cutting can be performed without stopping the processing head, resulting in a reduction in processing time. (See Patent Document 1).

  As described above, in order to realize a high-speed and smooth movement of the machining head that does not cause mechanical vibration, it is necessary to limit the jerk of the machining head. For that purpose, it is relatively easy if the movement path including the time of machining is constituted by a spline curve or a Bezier curve. However, these curves are complicated in shape and are difficult to form (program). Therefore, it is very useful that the movement path can be easily configured only from a straight line, a circle and an ellipse or a combination thereof.

  Therefore, in order to solve such a problem, the present invention provides a laser cutting method for cutting round holes, long holes, square holes, corner loop parts, micro joint parts, contour shapes, etc. This makes it possible to generate a trajectory path and execute a movement according to the trajectory path in order to perform laser cutting at high speed and with high accuracy while avoiding a typical shock. Alternatively, it enables generation of a trajectory path and execution of movement according to the trajectory path for laser marking with high speed and high accuracy while avoiding mechanical shocks, and a complicated shape such as a character. Similarly, in welding, a welding shape specified by a line, arc, ellipse, or a combination thereof is applied at high speed and high precision while avoiding mechanical shock. And an object in for laser welding, to provide a laser processing method and laser processing apparatus for enabling execution of the movement in accordance with the generation and the trajectory path of the trajectory path.

  In order to achieve the above-mentioned object, the invention according to claim 1 condenses the laser beam to irradiate the workpiece, and moves the machining head relative to the workpiece by a numerical controller. A laser processing method for performing laser processing by scanning a condensing point on a workpiece, and starting from a path section including a path for performing laser processing at a commanded tangential speed, which consists of a straight line, an arc, or an ellipse. A step of setting an acceleration section consisting of any one of a straight line, an arc and an ellipse having the same radius of curvature at a point prior to the path section for laser processing; and the path section from the start point of the acceleration section. In the first coordinate system describing the two consecutive sections including the above, each component of the tangential direction and the normal direction of the speed, acceleration, and jerk of the relative movement in the first coordinate system describing the sections, the first coordinate system Each axis Limiting at least one of the magnitudes of the absolute value of the component and the combined component of the axial components, and setting a movement path section in which laser processing toward the start point of the acceleration section is not performed, and the movement Regarding the path section, in the second coordinate system describing the movement path section, the tangential and normal components of the speed, acceleration and jerk of the relative movement, and each axis of the second coordinate system Restricts at least one of the magnitude value of the direction component and the combined value of the axial direction components, and superimposes the movement command in the acceleration section before the deceleration of the movement path section is completed. And a step of ending the deceleration of the moving path section before the end of the acceleration section, and providing a laser processing method.

  The invention according to claim 2 condenses the laser beam to irradiate the workpiece, and moves the machining head relative to the workpiece by means of a numerical control device, thereby setting the focal point on the workpiece. A laser processing method for performing laser processing by scanning, which is composed of a straight line, an arc, or an ellipse, and has the same radius of curvature at the end point of a path section including a path for laser processing at a commanded tangential speed. A step of setting a deceleration section composed of any one of a straight line, an arc, and an ellipse that are in contact with each other following a path section in which laser processing is performed, and two consecutive sections including the path section to the end point of the deceleration section In the first coordinate system describing these sections, the tangential and normal components of the relative movement speed, acceleration and jerk, the axial components of the first coordinate system, and Each axis Limiting at least one of the magnitudes of the absolute value of the composite component of the components, and setting a movement path section in which laser processing is not performed from the end point of the deceleration section to a path section in which the next laser processing is performed; In the second coordinate system describing the movement path section, the tangential direction and normal direction components of the relative movement speed, acceleration, and jerk, and the second coordinate system for the movement path section At least one of the absolute value of each axial direction component and the combined component of each axial direction component, and after the start of the deceleration section, the movement command of the movement path section is superimposed and commanded There is provided a laser processing method comprising the steps of:

  A third aspect of the present invention provides the laser processing method according to the first or second aspect, wherein the first coordinate system and the second coordinate system are the same coordinate system.

  The invention according to claim 4 is the laser processing method according to claim 2, further comprising a step of stopping laser irradiation at a contact point between a path section for performing the laser processing and the deceleration section. provide.

  The invention according to claim 5 is the laser processing method according to claim 1 or 2, wherein a command speed for instructing a speed between the acceleration section or the deceleration section and a moving path section in which the laser processing is not performed, Instructing the same jerk and acceleration, and further, setting a moving path end section having the same tangent length as the tangent length of the acceleration section or the deceleration section as the end of the moving path section not performing the laser processing. A laser processing method is provided.

  According to a sixth aspect of the present invention, in the laser processing method according to the first or second aspect, the length of the moving path section that does not perform laser processing sandwiched between the plurality of sections that perform laser processing is the deceleration section and the If it is shorter than the sum of the acceleration sections, the method further includes a step of adjusting a time required for the movement of the movement path section where the laser processing is not performed to be equal to a sum of the times required for the acceleration section and the deceleration section. A laser processing method is provided.

  The invention according to claim 7 is the laser processing method according to claim 1, wherein the laser processing method according to claim 1 performs processing along a circular path, wherein the circular path is viewed from a starting point of a moving path section composed of a line segment toward the circular path. The method further includes the step of setting the farthest point on the path as the start point of the path section for performing laser processing and setting the start point of the acceleration section before the path section for performing laser processing as the end point of the movement path section. A laser processing method is provided.

  Furthermore, the invention according to claim 8 is the laser processing method according to claim 1, wherein the cutting is performed along a path of a graphic composed of an arc and a line segment, and the movement is made of a line segment toward the path of the graphic. The farthest point on the arc of the path of the figure as seen from the starting point of the path section is set as the starting point of the path section for performing laser processing, and the starting point of the acceleration section before the path section for performing laser processing is set. Provided is a laser processing method further including a step of setting as a moving path section end point.

  The invention according to claim 9 is the laser processing method according to claim 1, 2 or 6, wherein the laser processing is performed using the loop type movement path section of the corner edge shape portion, and the laser processing toward the corner portion. On the extension of the section, a deceleration section, an acceleration section preceding the laser processing section starting from the corner portion, and a movement consisting of a line segment or an arc with the end point of the deceleration section and the start point of the acceleration section as the start point and the end point, respectively. There is provided a laser processing method further comprising a step of setting a path section.

  A tenth aspect of the present invention is the laser processing method according to the first, second, or sixth aspect, wherein the microjoining is performed, wherein a deceleration section is formed on an extension of the laser processing section toward the microjoint portion, and the microjoint Further comprising a step of setting an acceleration section preceding a laser processing section starting from a portion, and a movement path section composed of a line segment or an arc having an end point of the deceleration section and a start point of the acceleration section as a start point and an end point, respectively. A laser processing method is provided.

  The invention according to claim 11 is the laser processing method according to claim 5, further comprising the step of starting feedback control for maintaining a constant distance between the processing head and the workpiece in the acceleration section. Provide a method.

  The invention according to claim 12 condenses the laser beam to irradiate the work piece, and moves the machining head relative to the work piece by means of a numerical control device, thereby setting a condensing point on the work piece. A laser processing apparatus that performs laser processing by scanning, and has the same radius of curvature at the start point of a path section that includes a path for laser processing at a commanded tangential speed, and is composed of a straight line, an arc, or an ellipse. Means for setting an acceleration section consisting of any one of a straight line, a circular arc and an ellipse prior to a path section for laser processing, and two consecutive sections including the path section from the start point of the acceleration section, In the first coordinate system describing these sections, the tangential and normal components of the relative movement speed, acceleration and jerk, the axial components of the first coordinate system, and Each axis direction Means for restricting at least one of the magnitudes of the absolute values of the combined components and setting a movement path section that does not perform laser processing toward the start point of the acceleration section, and for the movement path section, the movement path section In the second coordinate system describing the tangential and normal components of the relative movement speed, acceleration and jerk, each axial component of the second coordinate system, and each axial direction Means for limiting at least one of the magnitudes of the absolute value of the composite component of the components and superimposing a movement command in the acceleration section before the deceleration of the movement path section is completed, and the acceleration section And a means for ending the deceleration of the moving path section before ending, and providing a laser processing apparatus.

  In the invention described in claim 13, the laser beam is condensed and irradiated to the workpiece, and the processing head is moved relative to the workpiece by the numerical control device, thereby the focal point on the workpiece is determined. A laser processing apparatus that performs laser processing by scanning, and has the same radius of curvature at the end point of a path section that includes a path for laser processing at a commanded tangential speed, and includes a straight line, an arc, or an ellipse. Means for setting a deceleration section composed of any one of a straight line, a circular arc and an ellipse following the path section for laser processing, and two consecutive sections including the path section to the end point of the deceleration section In the first coordinate system describing these sections, the tangential and normal components of the relative movement speed, acceleration and jerk, the axial components of the first coordinate system, and Each axis direction Means for restricting at least one of the magnitudes of the absolute value of the composite component of the minute, and setting a movement path section in which laser processing is not performed from the end point of the deceleration section to a path section for performing the next laser processing; In the second coordinate system describing the movement path section, the tangential direction and normal direction components of the relative movement speed, acceleration, and jerk, and the second coordinate system for the movement path section At least one of the absolute value of each axial direction component and the combined component of each axial direction component, and after the start of the deceleration section, the movement command of the movement path section is superimposed and commanded And a laser processing apparatus.

  According to the present invention, while maintaining the shape of the laser processing path, smoothly enter the laser processing path from the moving path without stopping or unnecessary deceleration while adding a certain limit to the jerk, or Since the laser processing path can be smoothly transferred to the movement path, high-speed and high-precision laser processing can be realized by a combination of simple path commands.

  Further, by making the first and second coordinate systems the same, the NC program can be simplified.

  By stopping the laser processing at the end point of the laser processing path, it is possible to move on the shortest path to the next laser processing path.

  The command speed for commanding the speed between the acceleration section or the deceleration section and the movement path section where the laser machining is not performed is commanded with the same jerk and acceleration, and the movement path having the same tangent length as the acceleration section or the deceleration section. By setting the end section to the end of the movement path section where laser processing is not performed, a special timing control means for controlling the start of the block on which the movement command is superimposed becomes unnecessary.

  If the length of the moving path section where laser processing is not performed between the sections where laser processing is performed is shorter than the sum of the deceleration section and acceleration section, it is necessary to move the moving path section where laser processing is not performed The time can be adjusted to be equal to the sum of the time taken for the acceleration and deceleration sections. Thereby, even when the processing paths that follow each other are close to each other, complicated processing is not involved.

  According to the present invention, in laser cutting for processing a round hole or a long hole, an NC that opens a piercing hole in an unnecessary portion by a simple algorithm without unnecessary deceleration and with a path limited to jerk. Since a program can be generated, high-speed and high-precision laser processing can be realized.

  Further, since the loop movement path or the micro joint machining part of the corner edge shape part can be realized by a simple algorithm and a path limited to the jerk, high-speed and high-precision laser machining can be realized.

  The distance between the machining head and the workpiece is measured, and during laser machining, feedback control is performed to keep the distance between the machining head and the workpiece constant. Since the distance between the workpiece and the workpiece is set, stable laser machining can be performed from the beginning of the machining path without unnecessary deceleration and stop, and high-speed and high-precision laser machining can be realized.

  As shown in FIG. 1, a laser processing apparatus 10 for carrying out the present invention may basically be a general laser processing apparatus, and includes a laser oscillator 12, a light guide optical system 14, a condensing optical system 16, and a scanning. It has a mechanism 18, a control device 20 and an automatic programming device 22. Hereinafter, each component and its function will be briefly described.

The laser oscillator 12 is a CO ₂ laser or a YAG laser, for example, and can output laser light of several watts to several kilowatts.

  The light guide optical system 14 includes a reflecting mirror or an optical fiber for guiding laser light to the processing head of the condensing optical system 16.

  The condensing optical system 16 includes a lens or a reflecting mirror having a curvature. The condensing optical system 16 also includes a processing nozzle 24 for blowing assist gas, and a processing head 26 having a position adjusting mechanism for adjusting the position of the condensing point and the workpiece in the laser beam optical axis direction. The processing head 26 further includes a distance sensor 28 that measures the distance to the workpiece. During laser processing, the distance between the processing head 26 and the workpiece is controlled to be constant based on the value measured by the distance sensor 28.

  The scanning mechanism 18 changes the position of the condensing point with respect to the workpiece. Specifically, the scanning mechanism 18 may move the machining head 26 or move the workpiece. Although it can take the form of an articulated robot, here, for the sake of simplicity, the machining head 26 is moved according to an orthogonal coordinate system.

  As shown in FIG. 2, the control device 20 includes a numerical control device 30 and a servo mechanism 32 for moving the scanning mechanism 18. The numerical controller 30 decodes an NC sentence such as a movement instruction sentence and issues a movement instruction to the servo mechanism 32. The servo mechanism 32 drives the scanning mechanism 18 by feedback control. The movement command for driving the scanning mechanism 18 is output to the servo motor command as a minute movement amount per unit time set in the numerical control device 30. This unit time is called an interpolation period, and is approximately 1 to 8 milliseconds. The unit of movement is usually 1 μm or 0.1 μm. In the movement command statement, an appropriate processing speed for performing laser processing can be designated. The speed can be specified by specifying the cutting speed in the movement command statement itself, by describing it in the form of machining conditions in the movement command statement and storing the machining speed in the machining conditions, or by setting the machining speed in advance. For example, there is a method of selecting a processing speed with an operation panel (not shown) provided in the numerical control device 30.

  Similarly, the speed of the moving path of the part not subjected to laser processing can be commanded by various methods. In the acceleration / deceleration for moving the scanning mechanism 18, the numerical control device 30 first plans a speed command as a movement command output in the interpolation cycle while considering the tangential acceleration and jerk limitations. The tangential speed is corrected so as not to exceed the limit for the acceleration in the normal direction in the arc path and the jerk in the normal direction for the connection point between the arc and the straight line. Instead of using the acceleration and jerk in the tangential and normal directions, the magnitude of the absolute value of each axial component of the first coordinate system or its combined component may be used. In this manner, the scanning mechanism is driven from the start point to the end point of a series of smoothly connected paths so that jerk, acceleration, and speed do not exceed the limit values. For each axis, jerk, acceleration and speed limit values are monitored.

  The laser processing apparatus described so far has been described as an integrated apparatus for performing laser processing. However, in order to obtain a desired shape, the laser processing apparatus further includes an automatic programming device 22 (FIG. 1) used online or offline. Also good. The automatic programming device 22 creates a movement command statement, that is, an NC program from graphic data. In laser cutting, the automatic programming device 22 generates an NC program from a desired shape by automatically calculating an approach path, a micro joint, a corner loop, a piercing command, and the like necessary for laser cutting based on instructions. . On the other hand, in automatic programming in laser marking, the automatic programming device can generate NC programs for characters and symbols. However, letters and symbols are also eventually described as figures consisting of line segments and arcs.

  The shape of a sheet metal product actually manufactured by laser cutting is described by a line segment and an arc, and is composed of a contour shape and a hole shape in the product. When laser cutting is performed, a plurality of products are arranged on the raw material plate, one point at a time, a method of cutting a desired shape, and a method of first cutting all the hole shapes and then cutting them out and then cutting the contour shape There is. In either method, the machining head cuts the product while alternately passing through a path section with a series of laser irradiations and a path section without laser irradiation.

  As for the point at which laser cutting is started, there is a case where it starts from one point of the cutting path, but since the processing result at the cutting start point is likely to be defective, a moving section (approach section) preceding the laser cutting path section is set. Conventionally, a part used as a product shape is a part cut after a predetermined time has elapsed from the start of laser processing (so-called approach processing).

  Hereinafter, an embodiment of the present invention will be described by taking an example of laser processing (cutting processing) of a metal sheet metal using the above-described laser processing apparatus.

  FIG. 3 is a diagram showing a relative movement path between the machining head and the workpiece in the first embodiment of the laser machining method according to the present invention. In the present embodiment, for convenience, an acceleration section 104 is set between a movement path section 102 indicated by a broken line where laser irradiation (processing) is not performed and a cutting path section 106 (here, an arc) where laser processing is performed indicated by a solid line. To do. Here, in the acceleration section 104, the absolute value of the acceleration and jerk is limited to within the allowable value for each of the tangential direction and normal direction of the path with respect to the cutting path section 106. Set to Therefore, the acceleration section 104 is an arc that touches with a radius of curvature close to the arc when the cutting path section 106 is an arc, and when the cutting path section 106 is a line segment, It becomes an arc with a large radius of curvature. This is because if the radius of curvature is different at the contact point between the acceleration section and the cutting path section, the additional speed in the normal direction increases even if the tangential speed is constant.

  In this embodiment, when cutting a round hole, the acceleration section 104 is formed on the circumference of the round hole, that is, the cutting path section 106. Further, a movement command in the acceleration section 104 is superimposed and commanded before the machining head deceleration in the movement path section 102 ends, and the movement path section 102 before the movement of the machining head in the acceleration section 104 ends. The deceleration at ends. On the other hand, in the conventional approach processing, as shown in FIG. 17, it is necessary to arrange the acceleration section in the round hole. Conventionally, when cutting the round hole c4, the acceleration section 15 where the machining head moved along the movement section 14 is transferred is not formed on the circumference of the round hole c4, but is arranged in the round hole c4. Conventionally, if this is not done, a part of the circumference of the round hole c4 will be cut twice, and the cut surface of that part cannot be avoided. The same can be said for approach processing to a cutting path section composed of line segments.

  Desirably, the movement of the last part of the movement path section 102 is such that the time when the movement of the movement path 102 is decelerated and the time when the acceleration section 104 ends and the time when the movement path 102 enters the cutting path section 106 coincides. The command and the movement command of the acceleration section 104 are superposed and commanded. This specific method will be described below with reference to FIG.

  As shown in FIG. 1, for convenience, a coordinate system S1 for instructing the movement path 102 and a coordinate system S2 for instructing the cutting path 106 are set. The movement path 102 can be described as moving linearly to the coordinates (X1, Y1) in the coordinate system S1, starting from the end point P of the cutting path processed immediately before the cutting path 106. On the other hand, the cutting path 106 is described on the coordinate system S2, and the starting point B of the cutting path 102 is a temporary origin. Next, the acceleration section 104 is set before the cutting path 106. Simply, if the jerk and acceleration of the tangential velocity at the starting point B or the constants for calculating them are determined, the tangential length or time required for acceleration can be calculated from a predetermined cutting speed. Therefore, an arc having the same radius of curvature as the cutting path section 102 and a length necessary and sufficient for acceleration is generated as the acceleration section 104. As a result, the acceleration section 104 is described as a movement from the point A to the point B, that is, a section moving with the radius R of the arc as a cutting path from the coordinates (X2, Y2) in the coordinate system S2, and the origin of the coordinate system S2 is The point B is changed to the point A as shown in FIG.

  From the above, the movement path 102 is changed so as not to go from the origin P to the coordinates (X1, Y1) but to the coordinates (X1-X2, Y1-Y2) in the coordinate system S1. Such generation of the acceleration section 104 and change of the movement path 102 may be instructed by the operator on the automatic programming device 22 described above, or may be automatically generated by the automatic programming device 22.

  In the movement path 102, at the beginning of movement, a movement command toward the coordinates (X1-X2, Y1-Y2) is given, and the machining head moves. The above-described numerical control device 30 can calculate the remaining time to the destination (point A) of the movement path 102 based on the moving speed and the jerk and acceleration that determine acceleration / deceleration. When the remaining travel time to the destination becomes equal to the time required for the acceleration section 104, the movement toward the origin of the acceleration section 104 is started. At this time, the numerical controller superimposes the movement command in the movement path section 102 and the movement command in the acceleration section 104 for each interpolation period, and outputs them to both the X and Y servo motors. In order to realize this, the numerical control device includes a movement command superimposing means for superimposing two coordinate system values and outputting them to the machine coordinate system, and a timing calculation control means for timing the start of the acceleration section. And have. (See FIG. 2).

  In this way, the processing head does not stop from the movement path section 102 to the cutting path section 106, and the jerk, acceleration, and speed of the processing head are all predetermined values in both the path tangential direction and the normal direction. Although described below, laser cutting can be performed at a predetermined cutting speed from the beginning of the cutting path section.

  The timing at which the end portion of the movement path section 102 starts to overlap with the acceleration section 104 is important, but basically, the deceleration stop of the movement path section 102, that is, the arrival of the destination in the coordinate system S1, is the end of the acceleration section 104. If it is before. Therefore, it is possible to add a slight margin here.

  Next, using the same concept as in FIG. 3, a moving method related to the end point of the cutting process will be described. Conventionally, when a round hole, a square hole, or a contour shape has been cut, the machining head stops at the end point of the cutting section, and at the same time, the laser output stops. Here, if a moving path section that is smoothly connected from the cutting section and is not subjected to laser processing is set, the processing head is moved without decelerating, and the laser output is stopped simultaneously with passing through the end point of the cutting section Since laser processing can be completed without decelerating the processing head, the processing time is shortened. However, it is difficult to generate the subsequent movement path section with the jerk, acceleration, and speed all limited within the allowable range. In particular, at the connection point between the arc and the line segment, or between the arcs having different radii of curvature, the tangential jerk, acceleration, and speed are all within the allowable range, but the normal acceleration May change greatly, that is, the absolute value of jerk may be abnormally large.

  Therefore, a convenient deceleration section composed of any one of a straight line, an arc, and an ellipse that are in contact with the same radius of curvature is set on the extension line of the end point of the cutting path section, following the path section on which laser processing is performed. Furthermore, the moving path section in which the laser processing toward the next cutting path section is not performed is set starting from the end point of the deceleration section. In this movement path section, the magnitudes of the absolute values of the tangential direction and normal direction speed, acceleration and jerk components of the path, the axial components of the coordinate system, or their combined components are limited. This will be specifically described below with reference to FIG.

  The cutting path section 106 and the subsequent deceleration section 108 similar to those in FIG. 3 are described in the same coordinate system S2 as in FIG. 3, and the moving path section following the deceleration section 108 to go to the next processing site after the processing is completed. 110 (illustrated by a broken line) is described in a coordinate system S1 similar to FIG. From the above limitation, if the cutting path 106 is an arc as shown in the figure, the shape of the deceleration section 108 is an arc having the same radius of curvature as the arc, and if it is a line segment, the line segment is an extension of the line segment in the same direction. It is preferable that

  Laser processing ends at a connection point C between the cutting path section 106 and the deceleration section 108, and the processing head smoothly stops at the end point D of the deceleration section 108 in the coordinate system S2. At the same time that the machining head passes through the end point C of the cutting path section 106 and enters the deceleration section 108 in the coordinate system S2, the movement of the machining head in the movement path section 110 toward the next start point P ′ is coordinate system S1. Is started. The movement command in the deceleration zone 108 in the coordinate system S2 and the movement command in the movement path zone 110 in the coordinate system S1 are commanded in a superimposed manner in the actual machine coordinate system. That is, for each interpolation cycle, the movement command for deceleration and the movement command for the movement path are added and distributed to the servo system of each axis.

  In this way, although the deceleration zone 108 is commanded with a simple arc and the movement path 110 is commanded with a simple line segment, the actual movement of the machining head is not limited to the arc or line segment or its simple It becomes a complex curve that is not a combination. However, at every moment from the deceleration section 108 to the travel path 110, jerk, acceleration and speed exceed the sum of the limit values of the cut path section and the travel path section in both the tangential direction and the normal direction. Can be maintained at no value. Therefore, the machining head can move from the cutting path section 106 to the movement path section 110 without receiving a mechanical impact, and when the machining head reaches the end point (point D) of the deceleration section 108 in the coordinate system S2, the machining head is processed. Since the head has already started moving on the movement path 110 in the coordinate system S1, it does not actually stop and the machining time can be shortened.

  The first embodiment of the present invention has been described above. According to this, the jerk in the normal direction, which could not be realized only by smoothly connecting the line segment or the arc between the moving path section and the cutting path section where the laser processing is not performed, is small below a predetermined value. While maintaining the value, the transition can be made without reducing the tangential speed. The limit values of jerk, acceleration, and speed in the movement path section and the cutting path section are set to half of the limit values allowed for the laser processing apparatus in mechanical design at least in the section where they are superimposed. In this case, even if each is added, the limit value of the laser processing apparatus is not exceeded, so that the path configuration is simplified. Further, by setting an acceleration section or a deceleration section before and after the cutting path, there is no restriction on the desired cutting shape. Since the acceleration section or the deceleration section and the end part or the start part of the movement path section commanded to be superimposed on each other are commanded as line segments or arcs, respectively, the NC program is created and the program created by the numerical controller Execution is easy.

Here, an example of an actual NC program in the first embodiment will be shown and the contents thereof will be described.
G00 X ₁ 40. Y ₁ 40. G02.9 X ₂ 10. Y ₂ 10. R10. S0 F8000;
In the above program example, the starting point of the laser machining section is the coordinates (50, 50), but since the radius of the round hole for cutting is 10, the automatic programming device sets the acceleration section 16 to the radius 10 It generates as 1/4 round, and according to this, the end point of the movement route section 102 is changed to (40, 40). The movement path 102 and the acceleration section 104 are simultaneously commanded in the same block, but “G02.9” in the program is a command to synchronize the timing at the end of deceleration in the movement path section 102 and the end of the acceleration section 104. Is a circular interpolation command. That is, it is calculated from the constants related to the jerk and acceleration of the laser machine and the command speed of the moving path, the constants related to the jerk and acceleration of the laser machine, and the command speed F8000 during machining. Circular interpolation toward X ₂ 10. Y ₂ 10. is started when the time taken by the acceleration section matches. The command values for the X ₁ and X ₂ coordinates are added at each interpolation cycle, and the command values for the Y ₁ and Y ₂ coordinates are also added at each interpolation cycle. In this way, the latter half of the movement route section and the acceleration section are commanded in an overlapping manner.

G02 J ₂ -10. S1000 F8000;
Next, laser cutting of a round hole is executed in the coordinate system S2. Since there are an acceleration section and a deceleration section before and after, laser cutting at a constant speed proceeds in this machining path section without acceleration / deceleration.

G00 X ₁ 90. Y ₁ 40. G02.8 X ₂ 10. Y ₂ 10. R10. S0 F8000;
Subsequently, for the deceleration zone 108 (FIG. 4), the automatic programming device generates a quarter arc path having the same radius as the machining path, as in the acceleration zone. Although the starting point of the movement path section 110 moves by that amount, only the coordinates of the end point are shown in the block, so this is an implicit coordinate position change. “G02.8” is a code for superimposing a circular movement command of the coordinate system S2 on a movement command of the coordinate system S1, and the movement in the movement path section 110 and the deceleration section 108 is executed at the same time. The coordinate system S1 The movement commands for the coordinate system S2 are superposed for each interpolation cycle.

  Further, as described above, it is possible to describe on the same coordinate system without using two different coordinate systems, thereby avoiding the complexity of the NC program. In this case, for a section instructed to move in succession consisting of the movement path section 102 and the acceleration section 104 or the deceleration section 108 and the movement path section 110, the section is executed later before the section to be executed first ends. The execution of the section to be started is started. Therefore, the numerical control device decodes at least one block in advance for the blocks that are originally sequentially processed, and determines whether or not to superimpose the movement commands of the adjacent blocks. This will be described below with an example of an actual NC program.

G00 X40. Y40.;
G02.9 X10. Y10. R10. S0 F8000;
The numerical control device executes the movement command to (40, 40), but prior to that, the block that executes the next acceleration section starting with “G02.9” is decoded in advance. “G02.9” is a clockwise arc command, and is a code indicating an acceleration section in which the overlapping movement with the preceding block is performed. However, the superimposition timing starts the acceleration section so that the end time of the preceding block coincides with the time when the acceleration section starting with “G02.9” ends.

G02 J-10. S1000 F8000;
The round hole is then laser cut.

G02.8 X10. Y10. R10. S0 F8000;
G00 X90. Y40.;
Here, “G02.8” is also a clockwise arc command, and is a code indicating a deceleration zone in which the superimposed movement with the subsequent block is performed. Blocks that begin with “G02.8” decelerate to a stop while drawing an arc trajectory. On the other hand, a subsequent movement command is started, and the speed gradually increases. Since the movement commands of the two blocks are superimposed, the machining head does not actually stop and moves to the next machining point.

  In the practice of the present invention, a simple line segment, arc, or ellipse is used as the movement command unit, but it is necessary to superimpose the movement commands on these paths during acceleration / deceleration. Therefore, in order to facilitate the calculation process, a movement command for each interpolation period generated for each axis generated in the movement path section and a movement command for each interpolation period generated for each axis generated in the machining path section It is preferable to give a command to the servo motor system after adding up each axis. This is shown in FIG. 2 above.

  The timing calculation control means included in the numerical controller 30 in FIG. 2 is for controlling the timing at which the acceleration section 104 is started in the above-described embodiment. The method for controlling the timing is, for example, as follows. First, the remaining time of the movement path section 102 is sequentially calculated from the movement speed command value in the movement path section 102 and constants that determine the jerk and acceleration of the laser beam machine. Similarly to the machining speed command value, the acceleration section 104 preceding the machining path 106 can also calculate the time required for this from constants that determine the jerk and acceleration of the laser machine. Here, if the remaining time of the movement path 102 is started at the moment when the time required for the machining section is shorter than the time obtained by adding one interpolation period, the acceleration section 104 ends immediately after the end of the deceleration of the movement path 102, The machining head can enter the machining path 106.

However, the programming method for designating the superimposition of the movement command in the movement path section 102 and the acceleration section 104 or the deceleration section 108 and the movement path section 110 is not limited to the above. For example, the above NC program can be described and executed as follows.
G00 X40. Y40.;
G09.9 G02 X10. Y10. R10. S0 F8000;
G02 J-10. S1000 F8000;
G02 X10. Y10. R10. S0 F8000;
G09.1 G00 X90. Y40.;
Here, “G09.9” is an instruction code for designating the start of the block when the preceding movement path 102 starts decelerating and the feed speed reaches the value designated by the block. Further, “G09.1” is a code for instructing the movement route section 110 that can be executed at the same time as the preceding machining route section 106 is started.

  In the embodiment described above, in practice, even if the processing head enters the deceleration zone 108, the laser irradiation is continued to some extent, that is, the laser processing is often completed by performing some overlap. This is because a general numerical control device executes a movement command at an interpolation cycle. Therefore, when machining at extremely high speed, if an overlap part is not set in the machining path on the NC program, a series (one round) This is because the laser processing may not be completed.

  However, in a certain type of numerical control device, the laser output can be finely controlled by giving timing data for controlling a minute time from the start of the interpolation cycle to the laser oscillator. In a laser apparatus equipped with such a numerical control device, laser irradiation may be stopped at the contact point between the path section for performing laser processing and the deceleration section. By finishing the laser processing together with the end of the cutting path, it is possible to move to the next laser processing path more quickly.

  Next, a relative movement path between the machining head and the workpiece in the second embodiment of the laser machining method according to the present invention will be described with reference to FIG. In the second embodiment, when the jerk and acceleration that determine acceleration / deceleration in the movement path 202 and the jerk and acceleration in the acceleration section 204 use the same numerical value, the portion including the end of the movement path 202 is included. By disassembling 202a, it is possible to issue a command in the form of simultaneously executing the end portion 202a of the movement path and the acceleration section 204.

  The operation of the automatic programming device in the second embodiment is as follows. First, the automatic programming device obtains the length of the acceleration section 204 from the jerk and acceleration so as to have a length necessary and sufficient to reach a predetermined machining (cutting) speed. Next, the length (the distance between the point A ′ and the point B) of the terminal portion 202a of the preceding moving path section 202 is the length of the acceleration section 204 (the length of the arc line connecting the points A and B). ) Is divided into different blocks so that it has the same length as. Thereby, the last block 202a of the newly generated movement route section 202 and the acceleration section 204 have the same time required for movement. Therefore, it is only necessary to give a superimposition command so that the end 202a of the movement path section 202 and the acceleration section 204 are executed in the same block without using the timing control means, and the configuration of the numerical control device is simplified. Of course, this can also be applied to the deceleration zone.

  The third embodiment to be described next can be applied when independent machining paths are close to each other, for example, when a plurality of round holes as shown in FIG. 6 are arranged and cut at extremely close intervals. In the case of FIG. 6, when the same deceleration section 308a (arc line AB) as above is set in the preceding machining path 306a and the above-described acceleration section 304b (arc line CD) is set in the subsequent machining path 306b, execution of the deceleration section 308a is performed. There is a possibility that the execution of the movement section 310 between the deceleration section 308a and the acceleration section 304b will end before the process ends. If it does so, the state where three of the deceleration area 308a, the movement area 310, and the acceleration area 304b will overlap will arise, and this is not preferable because the control becomes complicated. Therefore, by decelerating the moving speed of the moving path 310 or adjusting the constant for acceleration / deceleration of the moving path 310, the total time required for the deceleration section 308a and the acceleration section 304b and the execution of the moving path section 310 are adjusted. It is effective to make the time taken to be approximately equal. If such a process is performed, a state in which three of the acceleration section, the deceleration section, and the movement path section are overlapped can be avoided, and the control of the execution start timing of each can be facilitated.

  FIG. 7 is a diagram showing another specific example according to the third embodiment. As shown in the figure, when the machining path is composed of two line segments 306c and a line segment 306d intersecting at an end point, the line segment 306c is extended for the same reason as in FIG. There may be a case where three of the deceleration section 308c, the acceleration section 304d obtained by extending the line segment 306d, and the movement path section 310c that connects the deceleration section 308c and the acceleration section 304d overlap. Therefore, by decelerating the moving speed of the moving path 310c or adjusting the constant for acceleration / deceleration of the moving path 310c, the total time required for the deceleration section 308c and the acceleration section 304d and the execution of the moving path section 310c. Can be made substantially equal.

  In the above embodiment, the timing of laser irradiation at the start of the machining path section has not been described in detail. In the case of laser cutting, piercing is usually performed at the start of laser cutting in a processing path that forms a desired shape. For example, when laser processing a thin sheet metal of about 1 mm of mild steel, if a laser beam of several kilowatts is irradiated, a hole can be immediately opened in the sheet metal and cutting can be started. do not have to.

  However, when the laser output is low or the plate thickness is thick, it is necessary to select the laser light irradiation conditions and perform laser drilling on the same spot for a certain period of time to perform drilling. Once a hole is opened in the workpiece and a flow of laser beam and assist gas is formed, continuous cutting can be performed. Moreover, if the laser output is sufficiently high even if the plate thickness is somewhat thick, even if laser irradiation is started during the movement of the processing head, it is possible to start a cutting process by opening a hole. However, in this case, the shape of the piercing part is often worse than when the piercing process is stopped once. Therefore, if the laser processing is started after decelerating, the deterioration of the piercing portion can be alleviated to some extent. In addition, the quality of the piercing process depends on various factors such as the size of the beam spot at the focal point and the material of the workpiece. Determining at which point on the processing path such piercing processing is performed, and further, decelerating or stopping is an important issue that affects the processing time of laser cutting.

  When the piercing process is performed on the cutting path, the cutting time is shortened, so that the processing time is shortened. However, the finish after the cutting of the piercing portion is not bad. Therefore, in many cases, an approach portion is set and piercing is performed on an unnecessary portion of the workpiece. In this way, even if the laser cutting is started while moving the machining head without stopping, the shape of the cut part is not adversely affected.

  A fourth embodiment described next with reference to FIG. 8 is for performing piercing processing on an unnecessary portion of a workpiece when the present invention is applied to round hole cutting processing. Usually, an automatic programming device functions to connect a large number of round hole cutting parts in series via a movement path in accordance with an operator's instruction or automatically. Here, as shown in FIG. The shapes 406a and 406b are cut continuously. First, the farthest point B from the point P on the machining path 406a when the current position of the machining head is the point P is obtained. Similar to the first embodiment described above, an acceleration section 404a (arc line AB) and a deceleration section 408a (arc line BC) are set on the same circumference. Accordingly, the movement path section 402a in this case is determined as a movement command block to the starting point A of the acceleration section 404a. Further, the end point C of the deceleration section 408a is a start point for moving to the next arc (machining path 406b). In this way, the movement path of the machining head when machining two round holes is determined.

  In actual cutting, the acceleration section 406a and the end portion of the moving path 402a that precedes the acceleration section 406a are commanded so as to overlap with each other. Therefore, the actual locus of the machining head becomes a curve 403a that is somewhat offset inside the machining path 406a. . For example, by starting laser irradiation from a point after 2/3 of the acceleration section 404a has elapsed, cutting can be started from a point D inside the round hole (processing path 406a). According to this method, it is possible to reliably perform piercing processing on an unnecessary portion of the workpiece with an extremely simple algorithm.

  FIGS. 9A to 9D are diagrams showing a process of determining a locus when a plurality of round holes (processing paths 406a to 406d) are continuously cut by applying the method of FIG. . First, from the starting point P, the processing order of the round holes is designated manually or automatically (FIG. 9A). Here, it is assumed that the processing is performed in the order of the round holes 406a, 406b, 406c, and 406d.

  Next, as shown in FIG. 9B, the farthest point Ba on the circumference of the first round hole (406a) viewed from the start point P is obtained, and the acceleration interval for the round hole 406a is obtained by the same procedure as in FIG. 404a and the deceleration area 408a are produced | generated and a movement path | route is determined.

  Further, the same processing is performed for the second round hole 406b. That is, as shown in FIG. 9C, the farthest point on the circumference of the second round hole 406b seen from the end point Ca of the deceleration zone 408a in the round hole 406a is obtained and Bb is obtained by the same procedure as in FIG. An acceleration section 404b and a deceleration section 408b for the hole 406b are generated, and a movement route is determined.

  Thereafter, this is sequentially repeated to determine the movement path and the cutting path for the round holes 406c and 406d (FIG. 9D).

  The fifth embodiment to be described next with reference to FIG. 10 relates to the processing of a long hole frequently used at the site of sheet metal processing together with a round hole, and the concept is similar to that of the above-described fourth embodiment. Yes. Here, when the starting point P of the movement path 502 is set as a starting point, an acceleration section is set before starting processing from the farthest point on the long hole-shaped processing path 506 viewed from the starting point P. Is also possible. However, in the outline of the elongated hole shape, starting the machining path from a point on the circumference of the semicircle has fewer inflection points peculiar to the elongated hole than starting the machining path from a point on the line segment. It is preferable from the meaning. Actually, when the slot to be machined next is determined by some method, the automatic proramming apparatus obtains the end point B on the farthest semicircle as viewed from the current position P. Next, an arc AB connected with the same radius as the semicircle is created as an acceleration section 504. The movement route section 502 is a block for issuing a movement command to the starting point A of the acceleration section 504.

  In the sixth embodiment described below with reference to FIG. 11, the present invention is applied to a case where a loop type moving path is cut at a corner edge portion. In the sixth embodiment, it is assumed that the corner edge portion defined by the machining paths 606a and 606b is to be machined, and at that time, the machining head passes through a loop type movement path (a path composed of line segments 608, 602, and 604). To do. Here, when the material part including the loop type moving path may be discarded, the moving path may be cut by continuously irradiating the laser, but when the above part is also required as a product, Laser irradiation is stopped at the vertex Q of the corner, and the laser beam is again irradiated from the moment when the laser beam is stopped and the laser beam is stopped and the line Q 608, 602 and 604 is reached again. Such a processing method will be described in detail below.

  Actually, in the sixth embodiment, as shown in FIG. 11, a deceleration zone 608 is set on the extension of the first machining zone 606a preceded by the automatic programming device. Next, the acceleration section 604 is set by extending the front of the start point Q of the second machining section 606b. Further, the end point R of the deceleration zone 608 and the start point S of the acceleration zone 604 are connected as a travel route zone 602. Thus, the shape of the loop path defined by the deceleration section, the movement path section, and the acceleration section is determined by the superimposed movement command for the deceleration section and the movement path section, and the superimposed movement command for the movement path section and the acceleration section. In each of the deceleration section, the movement path section, and the acceleration section, both jerk and acceleration are limited within a predetermined range.

  Specifically, the five sections from the first machining path section 606a to the second machining path section 606b via the deceleration section 608, the movement path section 602, and the acceleration section 604 are divided into three blocks, that is, (first machining section 606a + They are classified into a deceleration zone 608), a movement route zone 602, and (acceleration zone 604 + second machining zone 606b), and the jerk is limited to a predetermined range for each of them. Therefore, continuous movement is performed at the joints (points R and S) between the blocks. The deceleration section 608 and the acceleration section 604 are set longer than the distance required for deceleration and acceleration, respectively, and the speed in the movement path section 602 is calculated backward from the time required for the deceleration section and the acceleration section. Alternatively, the process of the movement route section 602 may be completed before the process of the acceleration section 604.

A specific example of the NC program in the sixth embodiment is shown below. In the following programs, “S1000” and “S0” command laser output 1000 W and laser off, respectively, and “P3” indicates that the B3 block of the “G100” command ends with the block “N3”. .
N1 G01 X10. Y10. S1000;
N2 G01 X15. Y10. S0 G100 X14. Y12. P3;
N3 G01 X15. Y10.;
N4 G01 X0. Y-4 S1000;

  Also in the sixth embodiment, since both jerk and acceleration are limited for each of the deceleration section, the movement path section, and the acceleration section as described above, the loop path on which these movements are superimposed also has jerk and acceleration. Both are kept below a certain value. Accordingly, there is no inflection point such as a contact point between a line segment and an arc, and no sudden acceleration change occurs, so that mechanical shock is not applied to the laser processing machine, and high-speed driving is possible. .

  Further, by drawing such a loop-type moving path, laser processing can be performed at a constant cutting speed even in the corner portion. Therefore, even in the vicinity of the corner apex, laser processing under a certain condition can be realized, and a uniform cutting result can be obtained. On the other hand, in a processing method in which the corner portion is temporarily stopped or decelerated, the laser irradiation to the corner portion is large and the heat input by the laser increases, so that a uniform laser processing result cannot be obtained. Although there is an attempt to change the laser output according to the speed to make the heat input constant, the processing by the loop path can easily maintain the quality of the processing result of the corner portion. Therefore, it is effective not only for cutting but also for welding and marking.

12 (a) to 12 (d), there are two blocks, that is, (first machining section 606a + deceleration section 608) and (acceleration section 604 + second machining section 606b) as in the sixth embodiment shown in FIG. It is a graph which shows the locus | trajectory of the position of a process head, ie, the actual shape, speed, acceleration, and jerk of a loop type path | route part in the case of mutually orthogonally crossing. In particular, as shown in FIG. 12 (c), the magnitude of the acceleration of each block is limited within a range of ± 1 × 10 ⁻⁵ m / s ² , and as shown in FIG. The magnitude of the jerk of the block is limited to a range of ± 1 × 10 ⁻⁷ m / s ³ . Therefore, it can be seen that the jerk is within a certain range after the superimposition, and the acceleration is a continuous value.

  The seventh embodiment to be described next with reference to FIG. 13 relates to a so-called microjoint portion, and sets a deceleration zone and an acceleration zone at both the laser cutting end point and the laser cutting start point of the microjoint portion. The automatic programming device automatically generates a path in which the end point and the start point are connected by a machining path.

  In general micro joint processing, for example, as shown in FIG. 13A, in order to form the micro joint portion 70, the laser cutting path is temporarily ended at the end point (end point) A of the first processing path 706a, and then the next This starts again from the end point (start point) B of the approach path 703 that is substantially orthogonal to the second machining path 706b. In order to realize such a cutting path, as shown in FIG. 13B, a deceleration section 708a is set on the extension of the line segment 706a, and an acceleration section 704a is set before the micro joint approach path 703. ing. In this example, the laser cutting is finished at a constant speed until reaching the micro joint portion 70 (end point A) from the line segment 706a, loop path movement including the deceleration section 708a and the acceleration section 704a is performed, and the start point B of the approach path 703 is reached. Piercing is performed while moving the machining head. Further, after processing the approach path 703, loop path movement including the deceleration section 708b and the acceleration section 704b is performed, and the second processing path 706b is cut. In this way, it is possible to prevent concentration of laser heat input due to acceleration / deceleration with respect to the micro joint portion 70 and to obtain a good cutting result. Each machining path is discontinuous. However, by superposing the deceleration section or acceleration section according to the present invention and the movement path, the machining head without mechanical shock that maintains the limit to jerk can be used. Movement can be realized and high-speed machining is possible.

  Here, with reference to FIG. 14, movement of the machining head in the Z direction, that is, retraction and approach of the machining head from the workpiece will be described. For example, as described with reference to FIG. 3, in the movement path section 102 (line segment PA) that moves from one processing path section to the next processing path section, interference with the workpiece is avoided and the processing has already been completed. In order to avoid the influence on the part, the machining head is generally retracted away from the workpiece. For example, when the workpiece is a flat plate placed on the XY plane, the machining head is retracted in the Z direction (Z-position increases) in the movement path section (between PAs) as shown in FIG. When approaching the machining path, the workpiece is again approached. Here, since the workpiece is not necessarily a strict plane, a distance sensor that normally detects the distance between the machining head and the workpiece is used. The distance sensor is generally a capacitance type sensor that detects a capacitance between a nozzle of the machining head and a metal plate as a workpiece.

  A general distance sensor can detect when the distance between the machining head and the workpiece is about 8 mm or less, and the distance between the machining head and the workpiece is fed back by a numerical controller and a servo motor system. Be controlled. If the positional relationship between the workpiece and the laser focal point is not constant, there are many cases where laser processing is defective. Depending on the processing form, however, severe positional accuracy of ± 0.3 mm or less may be required. A certain amount of time is required to set the Z-axis by feedback control within this accuracy. In the conventional laser processing method, the three axes XYZ move toward the start point of the processing path or the start point of the approach path, and the distance between the processing head and the workpiece can be detected by the distance sensor. It is switched to feedback control by. Therefore, at the starting point of the machining path or the like, the machining head is necessarily stopped at the XY plane coordinates.

  In the example shown in FIG. 14, the automatic programming device makes a path so that the Z-axis decreases from before the start point A of the added acceleration section 104 and enters the detection range Z1 (for example, within 8 mm) of the distance sensor after the start point A. Generate. Then, during execution of the acceleration section 104, the distance between the machining head and the workpiece is feedback-controlled. Therefore, while the distance between the machining head and the workpiece is controlled to a predetermined value, the machining head does not stop moving continuously in a plane, and therefore does not spend time on the movement.

  In the embodiment described so far, the machining speed in the machining path section in which the acceleration section or the deceleration section is set before and after is a constant speed. However, as known in the art, when a circular arc or a bent portion having a small curvature radius exists in the machining path, the machining path may be appropriately decelerated so as not to impair the shape accuracy of the machining path. In particular, when moving the machining head of a laser beam machine, if the cutting speed specified by the acceleration performance is insufficient, the speed may continue to increase even after moving from the acceleration zone to the machining path zone. The deceleration may be started from the machining path section before the deceleration section.

  FIGS. 15A and 15B are graphs illustrating this. The graphs G1 and G2 show speed changes in the coordinate systems S1 and S2 described with reference to FIG. 3, respectively, the command speed V1 in the machining section is 10 m / min, and the command speed V2 in the movement path section is 30 m / min. . FIG. 15A shows a case where the command speed is reached in the acceleration section. On the other hand, FIG. 15B shows a case where the command speed V1 is not reached in the acceleration section and the speed is further increased in the machining section. In FIG. 15B, since the command speed in the coordinate system S2 does not become zero only in the deceleration zone, the command speed is decelerated from before entering the deceleration zone. However, even in the case as shown in FIG. 15B, if the minimum value V3 of the command speed in the machining path section is equal to or greater than a predetermined value, a machining result according to the machining at the command speed can be obtained. There is no. In the present invention, since the jerk in the tangential direction of the route section is limited (the jerk is a finite value), the command speed starts to change from a constant value (for example, H1 and H2 in FIG. 15A). (Part), the speed graph is not a polygonal line but a curved line as shown.

  In the above embodiment, when the movement path is indicated by a line segment, the actual movement does not necessarily follow the path on the line segment unless there is a restriction such as a restriction on the position of the point to be pierced. Instead, the path suitable for the movement of each axis may be followed. The above-described processing of the corner loop portion and the micro joint portion corresponds to this.

  As described above, the present invention is a technique in which laser processing can be performed without stopping as much as possible after limiting the speed, acceleration, and speed of movement of the laser processing head. In addition to the direct energy saving effect by shortening the processing time, the economic and environmental effects by reducing acceleration and deceleration are also great. Therefore, application in laser processing of cutting, welding, and marking is expected.

It is a block diagram which shows the basic composition of the laser processing apparatus which concerns on this invention. It is a block diagram which shows the structure of the control apparatus of the laser processing apparatus of FIG. It is a figure explaining the movement method of the process head which concerns on the 1st Embodiment of this invention, Comprising: It is a figure explaining the transition from a movement area to an acceleration area. FIG. 4 is a diagram for explaining the transition from the deceleration zone to the next movement zone in relation to FIG. 3. It is a figure explaining the movement method of the processing head which concerns on the 2nd Embodiment of this invention. It is a figure explaining the movement method of the processing head which concerns on the 3rd Embodiment of this invention. It is a figure explaining the other specific example of the moving method of the process head which concerns on the 3rd Embodiment of this invention. It is a figure explaining the movement method of the processing head which concerns on the 4th Embodiment of this invention. (A) It is a figure explaining the locus | trajectory of the process head in the case of cut | disconnecting a some round hole continuously, Comprising: It is a figure which shows the process sequence of a round hole, (b) It produced | generated about the 1st round hole It is a figure which shows the farthest point, an acceleration area, and a deceleration area, and is a figure which shows the state which performed the process similar to (c) and (b) about the 2nd round hole, (d) The process similar to (b) It is a figure which shows the state which performed for the 3rd and 4th round hole. It is a figure explaining the movement method of the processing head which concerns on the 5th Embodiment of this invention. It is a figure explaining the movement method of the processing head which concerns on the 6th Embodiment of this invention. (A) It is a graph which shows the locus | trajectory of the position of a processing head, (b) It is a graph which shows the speed of a processing head, (c) It is a graph which shows the acceleration of a processing head, (d) The jerk of a processing head It is a graph which shows. (A) It is a figure explaining the process path of a micro joint part, (b) It is a figure explaining the movement path | route of the process head for implement | achieving the process path of (a). It is a graph explaining the movement of the Z direction of a process head. (A) It is a graph which shows the moving speed of the process head in two coordinate systems, It is a figure similar to (b) and (a), Comprising: It is a graph which shows the case where the command speed of a process path area does not become a constant value. . (A) It is a figure explaining the conventional movement path | route in the case of performing a corner process, (b) It is a figure explaining the conventional movement path | route in the case of processing two round holes. It is a figure explaining the movement path | route in the conventional approach process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 20 Control apparatus 30 Numerical control apparatus 32 Servo mechanism 102 Movement path area 104 Acceleration area 106 Processing path area 108 Deceleration area

Claims (13)

Laser processing that condenses laser light and irradiates the workpiece, and performs laser processing by scanning the condensing point on the workpiece by moving the processing head relative to the workpiece with a numerical controller. A method,
Acceleration consisting of either a straight line, arc, or ellipse that has the same radius of curvature and touches the starting point of a path section that includes a path for laser processing at the commanded tangential speed. Setting the section prior to the path section for laser processing;
For two consecutive sections including the path section from the start point of the acceleration section, the tangential direction and normal line of the speed, acceleration, and jerk of the relative movement in the first coordinate system describing the sections. A laser heading toward the start point of the acceleration section, limiting at least one of the magnitudes of the absolute values of the direction components, the axial components of the first coordinate system, and the combined components of the axial components A step of setting a movement route section not to be processed;
Regarding the movement path section, in the second coordinate system describing the movement path section, the components of the tangential direction and normal direction of the speed, acceleration and jerk of the relative movement, At least one of the magnitudes of the absolute values of each axial component and the combined component of each axial component is limited, and the movement command in the acceleration section is superimposed before the deceleration of the movement path section is completed. Commanding steps,
Ending deceleration of the travel path section before the acceleration section ends;
A laser processing method comprising: Laser processing that condenses laser light and irradiates the workpiece, and performs laser processing by scanning the condensing point on the workpiece by moving the processing head relative to the workpiece with a numerical controller. A method,
Deceleration consisting of a straight line, arc, or ellipse that consists of a straight line, arc, or ellipse and that touches the end point of the path section that includes the path for laser processing at the commanded tangential speed with the same radius of curvature. Setting a section following a path section for laser processing;
With respect to two consecutive sections including the path section to the end point of the deceleration section, the tangential direction and method of the relative movement speed, acceleration, and jerk in the first coordinate system describing the sections. Limiting at least one of the magnitudes of the absolute values of each component in the linear direction, each axial component in the first coordinate system, and the combined component of each axial component, from the end point of the deceleration section, A step of setting a movement path section not performing laser processing toward a path section for performing the next laser processing;
Regarding the movement path section, in the second coordinate system describing the movement path section, the components of the tangential direction and normal direction of the speed, acceleration and jerk of the relative movement, At least one of the magnitudes of the absolute values of each axial direction component and the combined component of each axial direction component is limited, and the movement command of the movement path section is superposed and commanded after the start of the deceleration section. Steps,
A laser processing method comprising:   The laser processing method according to claim 1, wherein the first coordinate system and the second coordinate system are the same coordinate system.   The laser processing method according to claim 2, further comprising a step of stopping laser irradiation at a contact point between a path section for performing the laser processing and the deceleration section.   Command the command speed for commanding the speed of the acceleration section or the deceleration section and the moving path section where the laser machining is not performed with the same jerk and acceleration, and the same tangent as the tangent length of the acceleration section or the deceleration section The laser processing method according to claim 1, further comprising a step of setting a moving path end section having a length to an end of the moving path section where the laser processing is not performed.   When the length of the movement path section not performing laser processing sandwiched between the plurality of sections performing laser processing is shorter than the sum of the deceleration section and the acceleration section, the movement of the movement path section not performing the laser processing 3. The laser processing method according to claim 1, further comprising a step of adjusting a time required for the time to be equal to a sum of times required for the acceleration section and the deceleration section. The laser processing method according to claim 1, wherein processing is performed along a circular path,
The farthest point on the circular path as seen from the starting point of the moving path section consisting of the line segment toward the circular path is set as the starting point of the path section for performing laser processing, and the path section for performing laser processing is set. The laser processing method which further includes the step which sets the starting point of the previous acceleration area as a movement path | route area end point. The laser processing method according to claim 1, wherein the laser processing method cuts and drills along a path of a graphic composed of an arc and a line segment,
A path that is set at the farthest point on the arc of the path of the graphic as a starting point of the path section for performing laser processing, as viewed from the start point of the movement path section that is composed of line segments that are directed to the path of the graphic, and that is used for laser processing The laser processing method further including the step which sets the start point of the acceleration area before the area as a movement path | route area end point. The laser processing method according to claim 1, 2 or 6, wherein the laser processing is performed using a loop type movement path section of a corner edge shape portion,
A line with a deceleration section on the extension of the laser processing section toward the corner, an acceleration section preceding the laser processing section starting from the corner section, an end point of the deceleration section, and a start point of the acceleration section, respectively. The laser processing method which further has the step which sets the movement path | route area which consists of minutes or a circular arc. The laser processing method according to claim 1, 2, or 6, wherein micro joint processing is performed,
A deceleration section on the extension of the laser processing section toward the micro joint part, an acceleration section preceding the laser processing section starting from the micro joint section, an end point of the deceleration section, and a start point of the acceleration section, respectively, as a start point and an end point The laser processing method further includes the step of setting the movement path | route area which consists of a line segment or circular arc to perform.   The laser processing method according to claim 1, further comprising a step of starting feedback control for maintaining a constant distance between the processing head and the workpiece in the acceleration section. Laser processing that condenses laser light and irradiates the workpiece, and performs laser processing by scanning the condensing point on the workpiece by moving the processing head relative to the workpiece with a numerical controller. A device,
Acceleration consisting of either a straight line, arc, or ellipse that has the same radius of curvature and touches the starting point of a path section that includes a path for laser processing at the commanded tangential speed. Means for setting a section in advance of a path section for laser processing;
For two consecutive sections including the path section from the start point of the acceleration section, the tangential direction and normal line of the speed, acceleration, and jerk of the relative movement in the first coordinate system describing the sections. A laser heading toward the start point of the acceleration section, limiting at least one of the magnitudes of the absolute values of the direction components, the axial components of the first coordinate system, and the combined components of the axial components Means for setting a movement route section not to be processed;
Regarding the movement path section, in the second coordinate system describing the movement path section, the components of the tangential direction and normal direction of the speed, acceleration and jerk of the relative movement, At least one of the magnitudes of the absolute values of each axial component and the combined component of each axial component is limited, and the movement command in the acceleration section is superimposed before the deceleration of the movement path section is completed. Means for commanding,
Means for ending deceleration of the travel path section before the acceleration section ends;
A laser processing apparatus comprising: Laser processing that condenses laser light and irradiates the workpiece, and performs laser processing by scanning the condensing point on the workpiece by moving the processing head relative to the workpiece with a numerical controller. A device,
Deceleration consisting of a straight line, arc, or ellipse that consists of a straight line, arc, or ellipse and that touches the end point of the path section that includes the path for laser processing at the commanded tangential speed with the same radius of curvature. Means for setting the section following the path section for laser processing;
With respect to two consecutive sections including the path section to the end point of the deceleration section, the tangential direction and method of the relative movement speed, acceleration, and jerk in the first coordinate system describing the sections. Limiting at least one of the magnitudes of the absolute values of each component in the linear direction, each axial component in the first coordinate system, and the combined component of each axial component, from the end point of the deceleration section, Means for setting a movement path section that does not perform laser processing toward a path section for performing the next laser processing;
Regarding the movement path section, in the second coordinate system describing the movement path section, the components of the tangential direction and normal direction of the speed, acceleration and jerk of the relative movement, At least one of the magnitudes of the absolute values of each axial direction component and the combined component of each axial direction component is limited, and the movement command of the movement path section is superposed and commanded after the start of the deceleration section. Means,
A laser processing apparatus comprising:

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