JP2006224174A - Laser machining apparatus, and method for setting threshold of pulse energy - Google Patents

Laser machining apparatus, and method for setting threshold of pulse energy Download PDF

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JP2006224174A
JP2006224174A JP2005043556A JP2005043556A JP2006224174A JP 2006224174 A JP2006224174 A JP 2006224174A JP 2005043556 A JP2005043556 A JP 2005043556A JP 2005043556 A JP2005043556 A JP 2005043556A JP 2006224174 A JP2006224174 A JP 2006224174A
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laser beam
laser
energy
threshold value
measuring device
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JP2005043556A
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Japanese (ja)
Inventor
Kenichi Murano
Satoru Tamura
賢一 村野
悟 田村
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Sumitomo Heavy Ind Ltd
住友重機械工業株式会社
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Abstract

Provided is a laser processing apparatus capable of accurately determining a threshold value of pulse energy even when an optical apparatus for changing the average power of a pulse laser beam is inserted in a beam path.
A splitter 14 splits a pulse laser beam emitted from a laser light source 11 into a laser beam propagating along a measurement path and a laser beam propagating along a processing path. The holding table 28 holds the workpiece 16 on the processing path. The power measuring device 20 measures the average power of the laser beam propagating along the processing path over a certain period. The energy measuring device 17 measures the pulse energy of the laser beam propagating along the measurement path. The threshold value storage means 18a stores the threshold value of pulse energy. The control device 18 compares the measured value of the pulse energy measured by the energy measuring device with the threshold value stored in the threshold value storage means to determine the normality of the pulse energy.
[Selection] Figure 1

Description

  The present invention relates to a laser processing apparatus and a pulse energy threshold setting method, and more particularly to a laser processing apparatus and a pulse energy threshold setting method for processing a workpiece while monitoring the pulse energy of a pulse laser beam.

  FIG. 5 shows a block diagram of a laser processing apparatus disclosed in Patent Document 1 below. The pulse laser beam emitted from the laser oscillator 11 enters the partial reflection mirror 14 via the folding mirrors 12 and 13. The partial reflection mirror 14 reflects about 99% of the incident pulsed laser beam and transmits the remaining about 1%.

  The laser beam transmitted through the partial reflection mirror 14 enters the energy measuring device 17. The laser beam reflected by the partial reflection mirror 14 is condensed on the workpiece 16 by the machining lens 15. The energy measuring device 17 detects the pulse energy for each pulse and transmits the detection result to the control device 18.

  The control device 18 compares the detected pulse energy with a threshold value stored in advance in the memory 18a. When the detected pulse energy is lower than the threshold value, a detection signal is output to the trigger pulse generator 19. Upon receiving this detection signal, the trigger pulse generator 19 outputs a trigger pulse to the laser oscillator 11 to generate an additional laser pulse.

JP-A-9-253878

  Patent Document 1 does not describe a method for determining a threshold value of pulse energy. Usually, a beam shaping optical device such as a beam expander or a mask is inserted in the path of the laser beam from the laser oscillator 11 to the partial reflection mirror 14. Even if the average power of the laser beam output from the laser oscillator 11 is constant, when the beam shaping optical device is adjusted, the average power of the pulsed laser beam reaching the partial reflection mirror 14 changes. For this reason, even if the normality of the average power of the pulse laser beam output from the laser oscillator 11 is confirmed, it is determined whether or not the pulse energy detected by the energy measuring device 17 at that time is the original normal value. Can not.

  An object of the present invention is to perform laser processing capable of accurately determining a threshold value of pulse energy even when an optical device that varies the average power of a pulsed laser beam is inserted in the beam path. Is to provide a device. Another object of the present invention is to provide a method for determining the pulse energy threshold of this laser processing apparatus.

  According to one aspect of the present invention, a laser light source that emits a pulse laser beam, a laser beam that propagates a laser beam emitted from the laser light source along a measurement path, and a laser that propagates along a processing path A certain period of a branching device for branching into a beam, a holding base for holding a workpiece at a position where a laser beam propagating along the machining path is incident, and a laser beam propagating along the machining path Power measuring device for measuring the average power of the laser, energy measuring device for measuring the energy per pulse of the laser beam propagating along the measuring path, and threshold storage means for storing the threshold value of the pulse energy And a measured value of the pulse energy measured by the energy measuring device and a threshold value stored in the threshold value storage means, The laser processing apparatus is provided with a determining control apparatus in which the normality of the.

  According to another aspect of the present invention, there is provided an optical device that is disposed on a laser beam path between the laser light source and the branching unit and has a property of acting on the laser beam and reducing the power of the laser beam. A threshold condition setting method for a device added to the laser processing device, wherein the optical device is set to a state in which the optical device performs the same action as that for processing a workpiece, and the laser light source is A step of measuring laser power with the power measuring instrument and measuring pulse energy with the energy measuring instrument in a state where the workpiece is operated under the same conditions as when processing the workpiece; When the measured laser power is within the allowable range of the processing conditions, a threshold value is determined based on the measured pulse energy measured by the energy measuring device. Threshold condition setting method of the laser working apparatus and a step of storing the threshold in the threshold storage means.

  In order to measure the average power on the machining path, the influence of power fluctuations by various optical devices arranged in the laser beam path leading to the power measuring instrument is eliminated, and the pulse energy is determined based on the average power on the workpiece. The threshold value can be determined.

  FIG. 1 is a block diagram of a laser processing apparatus according to an embodiment. The laser light source 11 emits a pulse laser beam. As the laser light source 11, for example, a carbon dioxide laser oscillator or the like is used. The pulsed laser beam emitted from the laser light source 11 enters the partial reflection mirror (branching device) 14 via the beam shaping optical system 25. The beam shaping optical system 25 includes a beam expander 25a and a mask 25b. The beam expander 25a changes the beam diameter of the laser beam. A through hole is formed in the mask 25b. The central portion of the laser beam whose beam diameter has been converted by the beam expander 25a passes through the through hole, and the peripheral portion is shielded by the mask 25b. When the beam diameter is changed, the average power of the laser beam passing through the mask 25b changes.

  The partial reflection mirror 14 reflects most of the incident laser beam, for example, 90%, and transmits the remaining several%. The laser beam transmitted through the partial reflection mirror 14 propagates along the measurement path and enters the energy measuring device 17. The energy measuring device 17 measures energy per pulse (pulse energy) for each laser pulse. The measured value of the pulse energy is input to the control device 18 through the amplifier 23 having a variable gain in the form of an electric signal (specifically, voltage).

  The laser beam reflected by the partial reflection mirror 14 propagates along the machining path and enters the workpiece 16. A galvano scanner 21 and a processing lens 15 are arranged in the processing path. The galvano scanner 21 scans the laser beam in a two-dimensional direction. The processing lens 15 images the through hole of the mask 26 on the surface of the processing target 16. The workpiece 16 is held on a holding table 28 constituted by an XY stage or the like. The holding table 28 can move the workpiece 16 in a two-dimensional plane parallel to the surface.

  A power measuring instrument 20 is mounted on the holding table 28. The power measuring device 20 moves together with the workpiece 16. The laser beam propagating along the processing path can be incident on the power measuring device 20 by moving the power measuring device 20 by operating the holding table 28. The power measuring device 20 measures the power of the incident laser beam. When the laser beam to be measured is a pulse laser beam, an average power for a certain period, for example, 1 second is measured. The measured average power is input to the control device 18 via the amplifier 23.

  A temperature sensor 22 is attached to the energy measuring device 17. The temperature sensor 22 measures the temperature of the energy measuring device 17 and transmits the measurement result to the control device 18.

  A threshold value of pulse energy is stored in the threshold value memory 18a. The control device 18 reads the threshold value from the memory 18a, and compares the measured value of the pulse energy with the threshold value.

  The control device 18 transmits a control signal to the trigger pulse generator 19. The trigger pulse generator 19 transmits a trigger pulse to the laser light source 11 based on the received control signal. When receiving one trigger pulse, the laser light source 11 outputs one laser pulse.

  When the power of the laser beam emitted from the laser light source 11 or the setting of the beam shaping optical system 25 is changed, the pulse energy measured by the energy measuring device 22 changes. The dynamic range of the measured pulse energy is over 100 times. By adjusting the amplification factor of the amplifier 23 according to the assumed value of the pulse energy measured by the energy measuring device 22, it is possible to prevent the S / N ratio from being lowered.

  The energy measuring device 22 usually has temperature dependency. For this reason, it is preferable to perform temperature correction on the measurement result of the energy measuring device 22. Hereinafter, the temperature correction method will be described with reference to FIG.

  FIG. 2 shows the relationship between the voltage of the signal output from the energy measuring device 22, the temperature of the energy measuring device 22, and the pulse energy. The voltage of the signal output from the energy measuring device 22 is a value after being amplified by the amplifier 23. For example, when the output voltage is V1 (V) and the temperature measurement result is T1 (° C.), it is determined that the pulse energy is E11 (mJ). As shown in FIG. 2, the temperature of the energy measuring device 22 can be corrected by storing pulse energy in advance for a plurality of output voltages and temperatures. Note that temperature correction can be performed at an arbitrary output voltage and temperature by performing an interpolation calculation as necessary. Note that temperature correction can be performed even if a calculation formula for obtaining pulse energy from the output voltage and temperature is stored.

  Next, a threshold value determination method will be described with reference to FIG. Refer to FIG. 1 as necessary.

  FIG. 3 shows a flowchart of the threshold value determining method. First, in step S1, the beam shaping optical system 25 is set to the same state as in actual processing. Specifically, the beam diameter conversion magnification of the beam expander 25a, the relative positional relationship between the beam expander 25a and the mask 25b, and the like are made the same as those during actual processing. In step S2, a pulse laser beam is emitted from the laser light source 11 under the same conditions as in actual processing. In step S3, the power measuring device 20 is arranged in the machining path, the average power of the pulse laser beam is measured, and the pulse energy is measured for each laser pulse by the energy measuring device 17 on the observation path.

  In step S4, it is determined whether or not the measured average power is within an allowable range. If the measured average power is within the allowable range, in step S5, a threshold value is determined based on the measured value of pulse energy. The threshold value is, for example, about 70% lower than the average value of many measured values of pulse energy. The determined threshold value is stored in the threshold value memory 18a.

  When the average power measured in step S4 is out of the allowable range, in step S6, various optical devices are inspected and reset.

  In the method according to the embodiment, in step S3, the average power is measured on the machining path on which the workpiece 16 is arranged, and in step S4, the normality is confirmed. Therefore, the output power from the laser light source 11, the optical axis adjustment of the beam shaping optical system 25, the beam diameter conversion magnification of the beam expander 25a, etc. are guaranteed to be in a normal state, and the pulse energy in the normal state is reduced. A threshold can be set. The same effect can be obtained when an optical device that has a characteristic of acting on the laser beam and reducing its power is arranged in addition to the beam shaping optical system 25 or instead of the beam shaping optical system 25. . In the case where such an optical device is arranged, in step S1, the optical device is set to a state in which the same action as that during processing is applied to the laser beam.

  Next, with reference to FIG. 4, a method of performing laser processing using the laser processing apparatus according to the embodiment will be described. Refer to FIG. 1 as necessary.

  The beam shaping optical system 25 is adjusted to the same state as in actual processing, and the threshold value is set by the method shown in FIG. The workpiece 16 is placed on the holding table 28 shown in FIG. The pulse laser beam is emitted from the laser light source 11 and the galvano scanner 21 is driven, and the pulse laser beam is incident on a desired position of the workpiece 16.

  FIG. 4 shows the time change of the measured value of pulse energy during processing. The horizontal axis represents the elapsed time, and the vertical axis represents the measured value of pulse energy. The control device 18 compares the measured value of the pulse energy with the threshold value Jth for each laser pulse. When a laser pulse PL equal to or lower than the threshold value Jth is detected, for example, an additional laser pulse is applied to the same position of the workpiece 16. Thereby, generation | occurrence | production of processing defect can be prevented.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

It is a block diagram of the laser processing apparatus by an Example. It is a graph which shows the conversion table | surface which calculates | requires pulse energy from the output voltage and temperature of an energy measuring device. It is a flowchart which shows the method of determining the threshold value of the laser processing apparatus by an Example. It is a graph which shows an example of the time series of pulse energy measured with an energy measuring device. It is a block diagram of the conventional laser processing apparatus.

Explanation of symbols

11 Laser light source 14 Partial reflection mirror (branching device)
DESCRIPTION OF SYMBOLS 15 Processing lens 16 Processing object 17 Energy measuring device 18 Control apparatus 18a Memory for threshold value 19 Trigger pulse generator 20 Power measuring device 21 Galvano scanner 22 Temperature sensor 23 Amplification variable amplifier 25 Beam shaping optical system 28 Holding stand

Claims (4)

  1. A laser light source for emitting a pulsed laser beam;
    A branching device for branching the laser beam emitted from the laser light source into a laser beam propagating along a measurement path and a laser beam propagating along a processing path;
    A holding table that holds a workpiece at a position where a laser beam propagating along the processing path is incident;
    A power measuring device for measuring an average power of a laser beam propagating along the processing path for a certain period;
    An energy measuring device for measuring energy per pulse of the laser beam propagating along the measurement path;
    Threshold storage means for storing a pulse energy threshold;
    A laser processing apparatus comprising: a control device that compares a measured value of pulse energy measured by the energy measuring device with a threshold value stored in the threshold value storage means to determine normality of the pulse energy. .
  2.   The laser processing apparatus according to claim 1, further comprising an optical device disposed on a path of the laser beam between the laser light source and the branching device and having a characteristic of reducing the power of the laser beam.
  3. And a temperature sensor for measuring the temperature of the energy measuring device,
    The laser processing apparatus according to claim 1, wherein the control device corrects a measurement value measured by the energy measuring device based on a temperature measured by the temperature sensor.
  4. A laser light source for emitting a pulsed laser beam;
    A branching device for branching the laser beam emitted from the laser light source into a laser beam propagating along a measurement path and a laser beam propagating along a processing path;
    A holding table that holds a workpiece at a position where a laser beam propagating along the processing path is incident;
    A power measuring device for measuring an average power of a laser beam propagating along the processing path for a certain period;
    An energy measuring device for measuring energy per pulse of the laser beam propagating along the measurement path;
    Threshold storage means for storing a pulse energy threshold;
    A control device for comparing the measured value of the pulse energy measured by the energy measuring device with the threshold value stored in the threshold value storage means to determine the normality of the pulse energy;
    Threshold condition of a laser processing apparatus, which is disposed on a laser beam path between the laser light source and the splitter, and has an optical device that acts on the laser beam and has a characteristic of reducing the power of the laser beam A setting method,
    The optical device is set to a state where the laser beam is subjected to the same action as when processing the workpiece, and the laser light source is operated under the same conditions as when processing the workpiece. Measuring laser power with a power meter and measuring pulse energy with the energy meter;
    When the laser power measured by the power measuring device is within an allowable range of processing conditions, a threshold value is determined based on a measured value of pulse energy measured by the energy measuring device, and the threshold value A threshold value condition setting method for a laser processing apparatus, comprising: storing a threshold value in a storage means.
JP2005043556A 2005-02-21 2005-02-21 Laser machining apparatus, and method for setting threshold of pulse energy Pending JP2006224174A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008238247A (en) * 2007-03-28 2008-10-09 Hitachi Via Mechanics Ltd Laser energy measuring system and laser beam machining apparatus
US7985942B2 (en) 2004-05-28 2011-07-26 Electro Scientific Industries, Inc. Method of providing consistent quality of target material removal by lasers having different output performance characteristics
JP2014500148A (en) * 2010-11-18 2014-01-09 ブンデスドルッケライ・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング Laser apparatus and method for processing an article with a laser with controllable pulse energy
JP2014516411A (en) * 2011-04-19 2014-07-10 レイキャン テクノロジー カンパニー リミテッド(ス チョウ) Method and apparatus for scintillation pulse information acquisition
KR101451007B1 (en) * 2012-03-06 2014-10-17 스미도모쥬기가이고교 가부시키가이샤 Laser processing apparatus and laser processing method
JP2015223591A (en) * 2014-05-26 2015-12-14 住友重機械工業株式会社 Laser processor and laser oscillation method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0395184U (en) * 1990-01-11 1991-09-27
JPH11192570A (en) * 1997-10-28 1999-07-21 Matsushita Electric Ind Co Ltd Device and method of laser beam machining
JPH11320148A (en) * 1998-05-06 1999-11-24 Denso Corp Method and equipment for laser welding monitoring

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0395184U (en) * 1990-01-11 1991-09-27
JPH11192570A (en) * 1997-10-28 1999-07-21 Matsushita Electric Ind Co Ltd Device and method of laser beam machining
JPH11320148A (en) * 1998-05-06 1999-11-24 Denso Corp Method and equipment for laser welding monitoring

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7985942B2 (en) 2004-05-28 2011-07-26 Electro Scientific Industries, Inc. Method of providing consistent quality of target material removal by lasers having different output performance characteristics
JP2008238247A (en) * 2007-03-28 2008-10-09 Hitachi Via Mechanics Ltd Laser energy measuring system and laser beam machining apparatus
JP4514767B2 (en) * 2007-03-28 2010-07-28 日立ビアメカニクス株式会社 Laser energy measuring device and laser processing device
JP2014500148A (en) * 2010-11-18 2014-01-09 ブンデスドルッケライ・ゲゼルシャフト・ミト・ベシュレンクテル・ハフツング Laser apparatus and method for processing an article with a laser with controllable pulse energy
JP2014516411A (en) * 2011-04-19 2014-07-10 レイキャン テクノロジー カンパニー リミテッド(ス チョウ) Method and apparatus for scintillation pulse information acquisition
US9772408B2 (en) 2011-04-19 2017-09-26 Raycan Technology Co., Ltd. (Su Zhou) Method and device for extracting scintillation pulse information
KR101451007B1 (en) * 2012-03-06 2014-10-17 스미도모쥬기가이고교 가부시키가이샤 Laser processing apparatus and laser processing method
JP2015223591A (en) * 2014-05-26 2015-12-14 住友重機械工業株式会社 Laser processor and laser oscillation method

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