JP4628129B2 - Laser processing method and apparatus - Google Patents

Description

  The present invention relates to a laser processing method for laser processing a hole surrounded by a closed curve, for example, on a plate-shaped workpiece, and a laser processing apparatus used for the laser processing method, and more specifically to perform hole processing on a workpiece. The present invention relates to a laser processing method and apparatus that does not adversely affect the cutout piece and the inner peripheral surface of the hole even when the cutout piece cut out from the workpiece drops and falls in the hole.

  Conventionally, as shown in FIG. 4, when the workpiece W supported by a plurality of skids or needle ridges 3 on the workpiece table 1 is irradiated with laser light from the laser processing head 5 to perform hole processing, the workpiece W is cut from the workpiece W. When the cut-out piece B that has been extracted falls in the hole 7, it falls off at an angle. As described above, when the cut piece B falls from the hole 7, the laser beam is irradiated to the vicinity of the contact position between the cut piece B and the inner peripheral surface of the hole 7. Is melted and the melt may adhere to the inner peripheral surface of the hole 7.

There exists patent document 1 as a prior example aiming at solving the said problem.
JP 2004-122217 A

  In the invention described in Patent Document 1, when laser processing a hole surrounded by a closed curve, a minute protrusion is formed during laser processing along the closed curve to separate a cut piece, and then The projection is processed.

  According to the invention described in Patent Document 1, although adhesion of the melt to the inner peripheral surface of the hole is reduced, laser processing is performed to remove minute protrusions after performing laser processing along a closed curve. There is a need, and further improvements are required in order to improve the efficiency of laser processing.

The present invention has been made in view of the conventional problems as described above. The laser processing head is irradiated with laser light from the laser processing head, and the laser processing head is moved relative to the work and surrounded by a closed curve. A laser processing method for laser processing a hole, wherein laser processing is started from within or outside the region surrounded by the closed curve, and the laser processing head reaches the closed curve position from the arrival position along the closed curve. Laser processing is performed, and after the laser processing head arrives again at the reaching position , the laser processing head from the reaching position along the closed curve performs laser processing between the processing position on the upper surface and the processing position on the lower surface of the workpiece. when passing through the distance corresponding to the difference caused by the traveling direction of the molten delay, der those characterized by zero laser output .

In addition, it supports a laser processing head that irradiates a workpiece with laser light from a laser oscillator, laser output control means that can control the output of laser light emitted from the laser processing head to the workpiece, and a workpiece to be laser processed. When the laser machining of the workpiece table relatively movable with respect to the laser processing head and the hole surrounded by the closed curve to the workpiece, the relative movement of the laser processing head along the closed curve, from the arrival position where the laser machining head to the closed curve position to start the laser processing from the area already or outside the area surrounding reaches the closed curve, the laser processing head, a processing position of the processing position and the lower surface of the upper surface of the workpiece passage detection means for detecting whether or not passing through the distance corresponding to the difference caused by the traveling direction of the molten delay of laser processing , The laser output control means simultaneously with the passage detection of the passage detecting means, it is characterized in that it comprises an operation control means for controlling the laser output zero.

Further, in the laser processing apparatus, the operation control means, characterized in that it comprises a function of controlling the speed increasing the relative moving speed of the work table to the passage detection simultaneously with the laser processing head of the passing detection means It is what.

  According to the present invention, when the hole surrounded by the closed curve is laser processed to separate the cutout piece from the work, the laser output is made substantially zero almost simultaneously with the dropout of the cutout piece being separated from the work. It is possible to prevent the cutout piece after being separated from being irradiated with a laser beam and prevent a part of the cutout piece from being melted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A laser processing apparatus 11 according to the present embodiment is conceptually and schematically shown in FIG. A laser processing head 15 that irradiates the workpiece W with the laser beam LB oscillated from the laser oscillator 13 is provided. The nozzle tip 17 provided in the laser processing head 15 is provided with a gap sensor (not shown) for detecting a gap between the surface of the workpiece W and the nozzle tip 17. By controlling the Z-axis motor 19 based on the detection, the gap between the workpiece W and the nozzle tip 17 is always controlled to be constant during laser machining of the workpiece W.

  Further, the laser processing apparatus 11 is provided with laser output control means 14 capable of controlling the output of the laser beam LB emitted from the laser oscillator 13 and irradiated from the laser processing head 15 to the workpiece W. The laser output control means 14 is composed of, for example, a shutter mechanism that can freely throttle and block laser light. However, the laser output control means may be configured to control the power supplied to the laser oscillator 13.

  The work W is supported on a work table 1 having a needle ridge 3 and the like. The work table 1 is configured to be movable in the X and Y axis directions relative to the laser machining head 15 by driving a servo motor 21 such as an X axis servo motor or a Y axis servo motor. The relative movement position of the workpiece W in the X and Y axis directions with respect to the laser processing head 15 is always detected by a position detecting means 23 such as a pulse encoder provided in the servo motor 21.

  The movement of the laser processing head 15 and the workpiece W in the X and Y axis directions is relative, and one of the laser processing head 15 and the workpiece W may be moved in the X and Y axis directions. Moreover, it is good also as a structure which moves one side of the laser processing head 15 or the workpiece | work W to an X-axis direction, and the other to a Y-axis direction. By the way, since this kind of laser processing apparatus is well-known, more detailed description is abbreviate | omitted.

  Further, the laser processing device 11 is provided with a control device 25 such as a CNC for controlling the laser processing device 11. The control device 25 is provided with program analysis means 29 for analyzing a machining program for laser machining input from the input means 27, and based on the analysis of the program analysis means 29, the laser oscillator 13, laser Operation control means 31 for controlling operations of the output control means 14, the Z-axis motor 19, the servo motor 21 and the like is provided.

  Further, the control device 25 is provided with passage detection means (comparison detection means) 33. When the hole surrounded by the closed curve is laser processed on the workpiece W, the passage detection unit 33 starts laser processing with a position within or outside the area surrounded by the closed curve as a start position, and performs relative movement. Thus, it is detected whether or not the laser processing head 15 has passed the arrival position at which the laser processing head 5 has reached the closed curve position when the laser processing head 15 is moved along the closed curve. . The passage detection means 33 outputs a command signal to the operation control means 31 after a lapse of a short time from the detection of the passage or after a slight movement from the arrival position.

  When the command signal is input, the operation control unit 31 controls the operation of the laser output control unit 14 to make the laser output substantially zero or zero, and controls the operation of the servo motor 21. The relative moving speed of the laser processing head 15 along the closed curve is controlled in a non-stop state. That is, the relative moving speed is controlled so as to decelerate or increase, or to maintain a constant speed.

  The slight time or the slight movement distance after the laser processing head 15 passes the arrival position is stored in advance in the storage means 35 based on trial laser processing performed in advance before laser processing of the workpiece W is started. The data is used. Note that the short time or the slight movement distance stored in advance in the storage means 35 is data based on data previously tested based on the material, thickness, processing conditions, etc. of the workpiece W, or data based on past processing results. Is desirable.

  In the above configuration, for example, as shown in FIG. 2A, when laser processing is performed on the workpiece W along a closed curve 41 having an appropriate shape, a portion of a region surrounded by the closed curve 41 (cutout piece) ) When 43 is scrapped, the laser processing start position P is set on the cutout piece 43. When the cutout piece 43 is a product, the start position P is set outside the area surrounded by the closed curve 41.

  When a machining program for performing laser machining of the workpiece W along the closed curve 41 is input from the input unit 27 to the control device 25, the machining program is analyzed by the program analysis unit 29 provided in the control device 25. Then, each operation unit of the laser processing apparatus 11 is controlled under the control of the operation control means 31, and laser processing is started from the start position P under preset processing conditions. Then, when laser processing proceeds and the laser processing head 15 reaches the position of the closed curve 41 by relative movement with respect to the workpiece W, laser processing is performed in the direction of the arrow from the arrival position S along the closed curve 41. is there.

  When laser processing is performed along the closed curve 41 under preset appropriate processing conditions (intermediate position T from reaching the arrival position S to the arrival position S again), the passage detection means (comparison detection means) 33 Thus, detection (detection) of whether or not the laser processing head 15 has reached the arrival position S again is performed. For this detection, for example, it is determined whether or not the same coordinate value is included in the machining program when the laser machining head 15 is moved relative to the workpiece W, and the command value is the coordinate of the arrival position S. In the case of the same value, it can be detected that the laser processing head 15 has reached the arrival position S again.

  When the passage detecting means 33 detects that the laser processing head 15 has reached the arrival position S, the position U has passed a short time or a short movement distance stored in the storage means 35 in advance. Processing conditions are changed. That is, at the elapsed position U, the laser output is controlled to be substantially zero or zero as shown in FIG. That is, when the laser output control means 14 including a shutter mechanism is operated, the laser beam LB oscillated from the laser oscillator 13 is cut off.

  Further, at the elapsed position U where the laser machining head 15 has moved slightly from the arrival position S, the rotation of the servo motor 21 is appropriately controlled in a non-stop state, and the relative movement speed of the laser machining head 15 with respect to the workpiece W is increased. It is controlled to a predetermined speed. Further, an assist gas pressure control means (not shown) is controlled to reduce the pressure of the assist gas ejected from the laser processing head 15 to the workpiece W. Thereafter, the relative movement speed is reduced at the position V and stopped at the position E.

  As described above, the control in the non-stop state at the elapsed position U is performed so as to pass at an appropriate speed without stopping at the elapsed position U. In this case, it is desirable to slightly increase the speed as shown in FIG. That is, even if the laser output is controlled to be substantially zero or zero at the elapsed position U, for example, when the laser beam is interrupted by a shutter mechanism or the like, a very short time is required until the laser output becomes zero. The portion where the workpiece W is irradiated with the laser light in this minute time is a portion that has already been subjected to laser processing, and is cut twice.

  In this case, when the relative movement of the laser processing head 15 with respect to the workpiece W is stopped, the laser light is concentrated and irradiated at one point in the minute time, so that it is not desirable to stop. Therefore, it is desirable to increase the relative moving speed of the laser processing head 15 with respect to the workpiece to avoid concentrating on one point.

  By the way, when laser processing of the workpiece W is performed, as shown in FIG. 3, when the traveling direction of laser processing is an arrow direction, the lower surface WL is melted with respect to the melting position (processing position) P1 of the upper surface WU of the workpiece W. The position (processing position) P2 tends to be delayed. Therefore, there is a difference H in the direction of laser processing between the processing position P1 on the upper surface WU of the workpiece W and the processing position P2 on the lower surface WL.

  Therefore, when laser processing is performed along the closed curve 41, even when the laser processing head 15 reaches the reaching position S, the workpiece W and the cutout piece 43 are slightly connected in the lower portion of the workpiece W. The cut piece 43 is cut and separated from the workpiece W when the elapsed position U is reached. That is, the distance from the arrival position S to the elapsed position U is substantially equal to the difference H.

  Accordingly, the laser output is controlled to be substantially zero or zero almost simultaneously with the cutting piece 43 being cut and separated from the workpiece W and dropped, and the relative moving speed of the laser processing head 15 with respect to the workpiece W is appropriately set in a non-stop state. Therefore, the laser beam LB is not irradiated to the cutout piece 43 falling from the workpiece W, and melting of a part of the dropped cutout piece 43 is suppressed. It is. Further, the cutout of the cutout piece 43 from the workpiece W is performed by one-step laser processing, and the hole surrounded by the closed curve can be efficiently processed.

  By the way, in the above description, the laser processing head 15 moves relative to the workpiece W, reaches the reaching position S and slightly passes through this reaching position S during laser processing along the closed curve 41. It has been described later that the laser output is substantially zero or zero, and the relative moving speed of the laser processing head 15 with respect to the workpiece W is appropriately controlled in a non-stop state.

  However, the following configuration is also possible. That is, the gap sensor provided at the nozzle tip 17 of the laser processing head 15 always detects the gap between the workpiece W and the nozzle tip 17 and performs laser processing along the closed curve 41 to drill the workpiece W. When the cutout piece 43 starts to fall, the laser output is almost zero or zero when the detected value of the gap sensor changes more than a predetermined value compared to the normal change range of the detected value. It is also possible to control the relative moving speed of the laser processing head 15 with respect to the workpiece W. Even in such a method, the same effects as described above can be obtained.

1 is a conceptual and schematic explanatory diagram of a laser processing apparatus according to an embodiment of the present invention. It is operation | movement explanatory drawing in the case of drilling. It is explanatory drawing which shows the shift | offset | difference state of the processing position of the upper surface of a workpiece | work at the time of laser processing, and a lower surface. It is explanatory drawing which shows the problem at the time of the hole processing by the conventional laser processing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Work table 11 Laser processing apparatus 14 Laser output control means 15 Laser processing head W Work LB Laser beam

Claims (4)

A laser processing method of irradiating a laser beam from a laser processing head to a workpiece and moving the laser processing head relative to the workpiece to laser-process a hole surrounded by a closed curve, the laser processing head being surrounded by the closed curve Laser processing was started from within or outside the region, laser processing was performed along the closed curve from the arrival position where the laser processing head reached the closed curve position, and the laser processing head reached the arrival position again . Thereafter, when the laser processing head passes a distance corresponding to a difference caused by a melting delay in the laser processing progress direction between the processing position on the upper surface and the processing position on the lower surface from the arrival position along the closed curve. A laser processing method characterized by setting the laser output to zero.   2. The laser processing method according to claim 1, wherein the relative moving speed of the laser processing head with respect to the workpiece is controlled in a non-stop state simultaneously with setting the laser output to zero. A laser processing head for irradiating a workpiece with laser light from a laser oscillator, a laser output control means capable of controlling the output of laser light irradiated to the workpiece from the laser processing head, and supporting the workpiece to be laser processed, When laser processing a workpiece table relatively movable with respect to the laser processing head and a hole surrounded by a closed curve on the workpiece, the laser processing head is moved along the closed curve by the closed curve. laser from the laser processing head to the closed curve position from the enclosed area already or regions outside the start of the laser processing reaches the arrival position, the laser processing head, the processing position and the lower surface of the working position of the upper surface of the workpiece a passage detecting means for detecting whether or not passing through the distance corresponding to the difference caused by the traveling direction of the molten delay in processing, this Said laser output control means simultaneously with the passage detection of the passage detecting means, the laser processing apparatus characterized by comprising an operation control means for controlling the laser output zero.   4. The laser processing apparatus according to claim 3, wherein the operation control unit has a function of increasing and controlling a relative moving speed of the work table with respect to the laser processing head simultaneously with detection of the passage of the passage detection unit. A laser processing apparatus.

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