JP2005081358A - Laser pulse monitoring method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To guarantee working quality to the workpiece to be worked by pulse lasers, and also to perform normal monitoring to the number of laser pulses and laser rising time by one sensor in a self-process. <P>SOLUTION: The number of lasers to be outputted to the number of laser application command pulses which irradiate the workpiece to be worked is monitored, further, the period from the rising time of the command for the application of pulses which irradiate the workpiece to be worked to the rising time of the pulses obtained by converting laser output into analog voltage by using a means of converting the same into voltage and thereafter by binarizing the analog voltage is measured, so that the service life of the lasers can be detected. Thus, the machining quality of laser machining to the workpiece to be worked is guaranteed, and further, loss on the production can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser pulse monitoring method for confirming laser processing quality in a self-process when a workpiece is irradiated with a laser by a laser processing apparatus or the like to perform hole processing or marking processing.

FIG. 4 shows a conventional method for laser processing a workpiece using a pulsed laser such as a CO ₂ laser. First, the processing method and procedure set by the laser pulse irradiation command output means 101 are transferred to the laser output control means 102 of the laser power source, and the laser beam emitted is emitted from the objective lens 104 by oscillating the processing laser 103. The aperture is narrowed down, and processing such as drilling is performed on the workpiece 106 by the laser spot 105. Here, in order to monitor the processing failure, some% of the laser energy is sent to the light detection means 107 such as a pyro detector by the beam splitter 108, and the voltage is converted by the heat quantity / voltage conversion means 109 such as an amplifier. If this value exceeds the value generated by the reference voltage generation means 111 such as a D / A converter by the preset reference voltage command means 110, the laser energy is regarded as being stably output and binary It is pulsed by the digitizing means 112 and counted by the pulse integrating means 115 such as a counter. Finally, a processing failure is determined by comparing the integrated number of pulses N with the number of pulses n set by the laser pulse irradiation command output means 101 using an arithmetic unit or the like, and the display means 116 notifies the laser processing failure. It was.
Japanese Patent Laid-Open No. 10-263859

  In the above conventional method, since the output waveform state of the processing laser 103 cannot be monitored, there is a problem in that it is impossible to detect an energy peak shortage and an irradiation time shortage caused by the life of the laser. Because laser processing can be performed as desired not only by the absolute amount of energy but also by the combination of peak value and time, it is not possible to detect processing defects due to laser life by simply measuring laser pulses or measuring laser energy. was there.

  As a technique for solving such problems, as a method for monitoring and determining both processing quality and laser defects during the own process, in the case of a waveform control type laser device, determination is made by comparing the laser output waveform with the reference waveform. The invention which performs is proposed (refer patent document 1). However, the present invention must make a comparative determination using the laser output waveform, and is not a simple and low-cost method.

  Therefore, in order to solve these problems, the present invention provides a laser lifetime in addition to the comparison with the integrated actual irradiation laser pulse number N with respect to the irradiation command pulse number n set by the laser pulse irradiation command output means 101. 2, the irradiation command pulse set by the laser pulse irradiation command output means 101, the actual irradiation voltage waveform converted by the laser heat quantity / voltage conversion means 109, and the binarization means 112 are formed. By comparing the actual irradiation pulse and measuring the time ΔT from the laser irradiation command pulse rising start time dt to the binarized pulse rising start time dT, the laser processing quality and the laser life can be simultaneously measured in the own process. A method / device for monitoring is provided.

  In order to solve the above-described problems, the laser pulse monitoring method / device of the present invention includes a step of converting a laser heat amount into a voltage value, and a reference voltage value necessary for laser processing such as preset hole processing and marking. Comparing the binarized data, a step of integrating the binarized data, a step of comparing the integrated number N of the integrated data with a preset number n of laser irradiation command pulses, N If both numerical values of n and n do not match, the process is determined to be a processing failure, and the time ΔT from the rise start time dt of the laser irradiation command pulse to the rise start time dT of the binarized voltage value is measured. And a step of determining that the laser lifetime is reached when ΔT is greater than a preset reference time.

  In the present invention, the processing method and procedure set by the laser pulse irradiation command output means are transferred to the laser output control means and the time measurement means, and the laser output control means oscillates the processing laser to process the workpiece. In the laser processing apparatus, a part of the laser energy supplied to the processing laser is sent to the light detection means, and the numerical value converted by the heat quantity / voltage conversion means is pulsed by the binarization means. When the value obtained by integrating the pulses is lower than the preset value of the reference voltage command means, it is determined that the laser processing is defective, and is transferred from the laser pulse irradiation command output means to the laser output control means. The difference ΔT between the rising start time dt of the irradiation command pulse and the rising start time dT of the pulse binarized by the binarizing means Measured by measuring means, and judging the laser lifetime by comparing the ΔT and the reference time.

  According to the present invention, in addition to measuring the number of laser processing defects, by monitoring the rising start time of the actual laser irradiation pulse with respect to the rising start time of the laser irradiation command pulse, the laser processing defects and the laser life can be determined. This can be done in real time with just one sensor. As a result, machining loss can be prevented in advance, and maintenance of quality performance of laser machining and improvement of productivity can be realized at low cost.

  According to the present invention, in addition to measuring the number of laser processing defects, by monitoring the rising start time of the actual laser irradiation pulse with respect to the rising start time of the laser irradiation command pulse, the laser processing defects and the laser life can be determined. This can be done in real time with just one sensor. As a result, machining loss can be prevented in advance, and maintenance of quality performance of laser machining and improvement of productivity can be realized at low cost.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3 (the same reference numerals are used for those having the same functions as the conventional means shown in FIG. 4). .

FIG. 1 shows an embodiment of the present invention in which a laser beam such as laser drilling or marking is performed on a workpiece using a pulse laser such as a CO ₂ laser.

  In FIG. 1, 101 is a laser pulse irradiation command output means, and here, an irradiation command is issued for laser output information. That is, output information of laser processing is given from the laser pulse irradiation command output means 101 to the laser output control means 102. The laser output control means 102 controls the output of the laser power source based on the command from the laser pulse irradiation command output means 101. Then, a laser control signal, that is, laser processing information is given to the processing laser 103, and the processing laser 103 performs laser processing according to the irradiation command based on the processing information. The processing laser 103 is optically focused through the objective lens 104 to form a laser spot 105, and the workpiece 106 is subjected to processing such as hole processing and marking processing. 107 is a light detector such as a pyrodetector that extracts and detects part of the laser energy emitted from the processing laser 103 by a beam splitter 108, and 109 converts the laser heat transferred from the light detector 107 into a voltage. The laser energy is converted into an analog value of voltage by the heat quantity / voltage conversion means. Reference voltage 110 is a reference voltage command means that can arbitrarily set a reference voltage used for determining a processing failure. Reference voltage 111 is a reference voltage generating means that uses a D / A converter or the like. The reference voltage value (analog value) from the reference voltage generation means 111 and the voltage value (analog value) converted by the laser heat amount voltage conversion means 109 are each pulsed by the binarization means 112 and compared. . Reference numeral 115 denotes pulse integration means for integrating the pulsed numerical values. 116 is a display means for displaying a laser processing defect based on the comparison result, 113 is a time measuring means, and binarization means from the rise start time dt of the laser irradiation command pulse issued by the laser pulse irradiation command output means 101. The time ΔT until the rise start time dT of the pulse binarized by 112 is measured. 114 compares the ΔT measured by the time measuring means 113 with a predetermined reference time, and if ΔT is greater than the reference time, the laser life determining means 117 determines that the laser life is 117, It is a display means.

  Next, the operation of the laser pulse monitoring method / apparatus of the laser processing apparatus will be described.

  First, regarding the processing failure determination, the laser output information set by the laser pulse irradiation command output unit 101 is transferred to the laser output control unit 102 such as a laser power source and the time measurement unit 113. In accordance with the laser processing information transferred to the laser output control means 102, the laser power control means 102 controls the laser power source to oscillate the processing laser 103. As a result, the laser beam is focused by the objective lens 104, and the laser spot 105 performs processing such as drilling and marking of the workpiece 106.

  Here, in order to monitor processing defects, some% of the laser energy is sent to the light detection means 107 such as a pyrodetector by the beam splitter 108 and converted into a voltage by the heat quantity / voltage conversion means 109 such as an amplifier. If this value is arbitrarily set by the reference voltage command means 110 and exceeds the value emitted by the reference voltage generation means 111 such as a D / A converter, the laser energy is regarded as being stably output. I can do it. The actual irradiation laser output value converted into the voltage is pulsed by the binarizing means 112 and counted by the pulse integrating means 115 such as a counter. Finally, the processing failure is determined by comparing the integrated pulse number N with the pulse number n set by the laser pulse irradiation command output means 101 using an arithmetic unit or the like. That is, when the numerical values of N and n do not match, it is determined that the processing is defective.

  Furthermore, as shown in FIGS. 2 and 3, the laser lifetime is measured by the laser pulse irradiation command output means 101 and the rise start time of the laser irradiation command pulse transferred to the time measurement means 113 as shown in FIGS. The time ΔT = dT−dt from the time dt until the pulse rising start time dT binarized by the binarizing means 112 is measured by the time measuring means 113, and ΔT1 is compared with ΔT when the reference time is ΔT1. Thus, the laser lifetime can be determined using the laser lifetime determination unit 114 such as a signal processing unit. As a result, even if a rise delay ΔT2 as shown in FIG. 3 with respect to the normal waveform of FIG. 2 occurs, detection becomes possible. That is, when laser processing is operating normally with respect to the pulse command, the waveform by actual irradiation shows a waveform as shown in the middle of FIG. The laser beam rises slightly after the start time dt of the irradiation command, and is ready for processing from the time dT when the reference voltage is reached. On the other hand, when the rise of the laser oscillation is greatly delayed, the rise delay time ΔT2 = dT−dt exceeds the reference time determined as the laser lifetime, and it is determined that the laser lifetime has been reached.

  Furthermore, in addition to the display means 116 for displaying the laser processing failure, the laser life display means 117 is installed in the same manner, so that the laser processing failure and the laser life can be notified in real time.

1 is a configuration explanatory diagram of a laser pulse monitoring device according to an embodiment of the present invention. FIG. It is an actual irradiation waveform schematic diagram with respect to the irradiation command pulse at the time of normal processing. It is an actual irradiation waveform schematic diagram with respect to the irradiation command pulse at the time of a laser defect. It is structure explanatory drawing of the conventional laser pulse monitoring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Laser pulse irradiation command output means 102 Laser output control means 103 Processing laser 106 Workpiece 107 Photodetection means 109 Heat quantity / voltage conversion means 110 Reference voltage command means 113 Time measurement means

Claims (3)

A step of converting the laser heat amount into a voltage value, a step of comparing the voltage value with a reference voltage value required for laser processing set in advance, and a step of binarizing, and a step of integrating the binarized data, A step of comparing the integrated number N of the integrated data with a preset number n of laser irradiation command pulses, a step of determining that the numerical values of N and n do not match, and a laser irradiation. A step of measuring a time ΔT from the rise start time dt of the command pulse to the rise start time dT of the binarized voltage value, and when the ΔT is larger than a preset reference time, the laser life is And a step of determining. A laser pulse monitoring method comprising: 2. The laser pulse monitoring method according to claim 1, wherein the quality of laser processing and the determination of laser life are displayed. Laser processing in which the processing method and procedure set by the laser pulse irradiation command output means are transferred to the laser output control means and the time measurement means, and the workpiece is processed by oscillating the processing laser by the laser output control means. In the apparatus, a part of the laser energy supplied to the processing laser is sent to the light detecting means, and the numerical value converted by the heat quantity / voltage converting means is pulsed by the binarizing means, and the pulses are integrated. When the numerical value is lower than the preset value of the reference voltage command means, it is determined that the laser processing is defective and the rise of the irradiation command pulse transferred from the laser pulse irradiation command output means to the laser output control means. The time ΔT from the start time dt to the rise start time dT of the pulse binarized by the binarization means is measured. In measured, the laser pulse monitoring apparatus characterized by determining a laser lifetime by comparing the ΔT and the reference time.

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