JP2004330277A - Laser beam machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laser beam machining device which can predict abnormality in machining accurately. <P>SOLUTION: The laser beam machining device is equipped with a laser oscillator 200, a machining processor 100 for machining a workpiece 4 with a machining head 11 which radiates a laser beam from the laser oscillator 200, a reflected light detector 10 for detecting reflected light, and a controller 300. The controller 300 is provided with a reference light discriminating part 41 that sets a reference value for predicting generation of plasma on the basis of reflected light during the normal machining after the start of the machining process, a threshold value forming part 42 that calculates a threshold value for predicting generation of plasma on the basis of the reference value and reflected light intensity from the reflected light detector 10, and a machining condition controlling part 60 that, if plasma generation is predicted on the basis of its threshold value, controls the laser oscillator 200 and the machining processor 100 so as to change the machining condition of the workpiece 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus that easily and accurately predicts abnormal processing in laser processing.
[0002]
[Prior art]
Conventionally, the state of processing of a workpiece by a laser processing apparatus is monitored by visual observation of the operator of the laser processing apparatus, and the operator determines whether the processing is normal. Then, when it is determined that the machining process is abnormal during the machining process, the laser machining apparatus is stopped, the machining condition is changed, and the machining process is resumed. However, the determination of whether the processing is abnormal or normal differs depending on the operator, and it is difficult to perform stable processing.
[0003]
Further, when a burst (processing blow-up phenomenon after processing failure occurs due to plasma generation) occurs, it is necessary to stop the laser processing apparatus, return the processing path to the burst generation position, and start processing again. For this reason, in order to perform stable processing, it is necessary to automatically monitor the state of the processing, determine whether the processing is normal, and accurately detect the burst occurrence position.
[0004]
In the laser processing apparatus described in Patent Document 1, the reflected light at the time of good cutting during processing is detected and recorded, and the processing condition data at the time of good cutting is registered in advance. Then, the reflected light at the time of actual processing is detected, and this reflected light is compared with the processing condition data at the time of good cutting to determine whether or not the actual processing state is good cutting.
[0005]
In the laser processing apparatus described in Patent Document 2, processing of a workpiece is divided into a plurality of processing blocks, and processing is performed using a predetermined processing program for each processing block. Then, when an abnormality in the machining process is detected, the machining process is stopped, and the machining head is moved backward by a predetermined distance along the executed machining path. Thereafter, the machining process is resumed by returning to the point where the abnormality of the machining process has occurred.
[0006]
[Patent Document 1]
JP 2001-314922 A (first item)
[Patent Document 2]
JP-A-6-202722 (Section 6)
[0007]
[Problems to be solved by the invention]
However, according to the former prior art, there is an error in the processing condition data registered in advance for good cutting, and there is a problem that it is not possible to cope with the case where the state of laser processing changes due to replacement of parts such as a processing head. there were. In addition, there are various materials and plate thicknesses for the workpieces, and it is difficult to register the machining conditions at the time of good cutting for all the workpieces.
[0008]
Furthermore, according to the latter prior art, since a machining program is set for each machining block, it is possible to reverse the machining path within the same block when machining processing abnormality occurs. However, there is a problem in that it is impossible to reverse the machining path across other machining blocks for an abnormality in machining processing that occurs near the boundary between machining blocks.
[0009]
The present invention has been made in view of the above, and an object of the present invention is to obtain a laser processing apparatus that predicts abnormalities in processing without registering in advance processing conditions for good cutting.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, the laser processing apparatus according to the present invention includes a laser oscillation unit that outputs a laser and a processing head that irradiates laser light from the laser oscillation unit. In the laser processing apparatus comprising: a processing unit that processes a workpiece; a detection unit that detects reflected light from the workpiece; and a control unit that controls the laser oscillation unit and the processing unit. The unit includes a reference light determination unit that sets a reference value for each processing process for predicting plasma generation based on reflected light during normal processing after the start of processing, and plasma generation based on the reference value. A plasma threshold generation unit for calculating a threshold for predicting the plasma, and a plasma generation is predicted based on a comparison between the reflected light intensity from the detection unit and the threshold for predicting the plasma generation. If it is determined that Zuma generator, characterized in that a machining condition changing unit for controlling the laser oscillating unit and / or the processing unit to change the working conditions of the workpiece.
[0011]
According to this invention, since the reflected light during normal processing after the start of processing is acquired as reference light, there is no need to register processing condition data in advance. Furthermore, in order to store the position where the burst is predicted to occur and the processing path after the position where the burst is predicted to occur, internal coordinate values in the block immediately before the block where the laser processing apparatus stopped are also generated. Can do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a laser processing apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.
[0013]
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a configuration of a laser processing apparatus according to an embodiment of the present invention. The laser processing apparatus includes a processing unit 100 that performs processing on the workpiece 4, a laser oscillation unit 200 that provides a laser for performing processing on the workpiece 4, and controls the processing unit 100 and the laser oscillation unit 200. It consists of the control part 300 which performs.
[0014]
The processing unit 100 detects the reflected light from the workpiece 4 to detect the occurrence of plasma or burst (processing blow-up phenomenon after processing failure occurs due to plasma), the reflected light detection unit 10, the workpiece 4. A machining head 11 for irradiating a laser for machining, a machining table 12 for placing the workpiece 4, and a Z-axis motor 13 for moving the machining head 11 in the vertical (Z-axis) direction.
[0015]
The reflected light detection unit 10 receives reflected light from the workpiece 4 when the workpiece 4 is irradiated with laser from the processing head 11, and inputs the light to the detection processing unit 2. A detection processing unit 2 that detects the input reflected light and inputs a detection signal to the reflected light determination unit 40 is provided.
[0016]
The processing head 11 irradiates the workpiece 4 from the tip portion of the processing head 11 with a laser supplied from the laser oscillation unit 200. Further, the upper part of the machining head 11 is connected to a Z-axis motor 13. The Z-axis motor 13 moves the machining head 11 in the vertical direction in response to a control signal from the control unit 300. The processing table 12 is a table on which the workpiece 4 is placed, and performs the laser processing while moving the workpiece 4 in the X-axis direction and the Y-axis direction.
[0017]
The laser oscillation unit 200 generates laser light used for processing the workpiece 4 and outputs the laser light to the processing head 11 and is output from the oscillator 20 by a control signal from the control unit 300. A beam correction unit 21 that adjusts the beam diameter of the laser light is provided.
[0018]
The control unit 300 includes a storage unit 70 and an NC control unit (not shown). The NC control unit includes a reflected light determination unit 40, a processing machine drive unit 50, and a processing condition control unit 60.
[0019]
The reflected light determination unit 40 is connected to the detection processing unit 2 and monitors the reflected light of the workpiece 4 during the processing. The reflected light determining unit 40 detects a plasma burst detection reference value (reflected light intensity during normal processing) VC as a reference for comparison with the reflected light generated during processing of the workpiece 4. 41 and a threshold generation unit 42 for calculating and setting a threshold for predicting plasma generation and burst generation based on the plasma burst detection reference value VC.
[0020]
The processing machine driving unit 50 determines and controls the operations of the processing head 11 and the processing table 12 when it is predicted that plasma is generated or when a burst is predicted. The machining condition control unit 60 determines and controls how to modify the machining conditions when plasma is predicted to be generated or when burst is predicted to occur.
[0021]
The storage unit 70 includes a position storage unit 71, a machining path storage unit 72, and a sequence state storage unit 73. When the position storage unit 71 divides the information instructed in block units by the NC program stored in the control unit 300 into interpolation units that are the minimum units processed by the NC control unit, and it is predicted that a burst will occur Are stored in interpolation units (coordinate values of the machining head 11 with respect to the workpiece 4).
[0022]
The sequence state storage unit 73 divides the information instructed in block units by the NC program stored in the control unit 300 into interpolation units, which are the minimum units processed by the NC control unit, and is predicted to generate a burst. In this case, the sequence state (assist gas conditions necessary for processing, etc.) is stored in interpolation units. The machining path storage unit 72 calculates and stores the machining path from the time when the burst is predicted to occur based on the machine value and the sequence state to the time when the laser machining apparatus is stopped in an interpolation unit. The machining path calculation unit 80 calculates machining conditions and the like for performing the re-machining process from the position where the abnormal machining process has occurred.
[0023]
FIG. 2 is a diagram illustrating configurations of the reflected light detection unit 10 and the control unit 300. The light receiving unit 1 is installed above the processing head 11, and the detection processing unit 2 is connected to the light receiving unit 1. When the light receiving unit 1 receives the reflected light from the workpiece 4, this is input to the detection processing unit 2.
[0024]
The reflected light determination unit 40 is connected to the detection processing unit 2, and the reference light determination unit 41 of the reflected light determination unit 40 performs normal processing according to the reflected light detection signal sent from the detection processing unit 2 during normal processing. A plasma burst detection reference value VC during processing is detected. Then, the threshold value generation unit 42 of the reflected light determination unit 40 calculates and sets a reference value (threshold value) for predicting plasma generation or burst generation based on the plasma burst detection reference value VC.
[0025]
The processing machine drive unit 50 and the processing condition control unit 60 are connected to the reflected light determination unit 40, and the processing machine drive unit 50 performs plasma based on the results obtained by the reference light determination unit 41 and the threshold value generation unit 42. The operations of the machining head 11 and the machining table 12 are determined and controlled when the occurrence of this is predicted or when the occurrence of a burst is predicted.
[0026]
At this time, the processing condition control unit 60 determines and controls how to correct the processing conditions when it is predicted that plasma is generated or when burst is predicted.
[0027]
Next, a processing procedure of the laser processing apparatus according to the first embodiment of the present invention will be described. FIG. 3 is a flowchart showing a processing procedure of the laser processing apparatus for performing plasma generation prediction according to the embodiment of the present invention.
[0028]
When the laser processing apparatus starts processing the workpiece 4, the light receiving unit 1 receives the reflected light from the workpiece 4 (step S100). FIG. 4 is a diagram showing the intensity of reflected light from the workpiece 4 observed during laser processing. In FIG. 4, the horizontal axis indicates the processing time, and the vertical axis indicates the reflected light intensity. Immediately after the processing of the workpiece 4 is started, a drilling process of the workpiece 4 called a piercing process is performed by a laser. The reflected light intensity becomes the highest during the piercing process, and the reflected light intensity becomes the minimum immediately after the end of the piercing process. This state is shown at time a in FIG.
[0029]
Thereafter, when the cutting process of the workpiece 4 by the laser is started, the reflected light intensity shows a stable value, and this is used as the reflected light intensity at the time of normal processing. The reflected light in the stable state becomes the plasma burst detection reference light, and the value of the reflected light intensity of the plasma burst detection reference light is set as the plasma burst detection reference value VC (step S110). Further, a plasma detection threshold value VP is calculated as a determination reference value for predicting plasma generation based on the plasma burst detection reference value VC (step S120).
[0030]
Here, the calculation method of the plasma detection threshold VP is set in advance. For example, the value of the reflected light intensity when the reflected light intensity is five times the plasma burst detection reference value VC is set as the plasma detection threshold value VP. Further, whether or not the generation of plasma is predicted may be determined based on the increasing / decreasing tendency of the reflected light. For example, it is predicted that plasma is generated when the increasing rate of the reflected light intensity increases at a predetermined rate or more.
[0031]
In FIG. 4, it is determined that the reflected light intensity reaches the plasma detection threshold VP at time b, and that plasma generation is predicted here (step S130). In this way, the determination as to whether or not plasma generation is predicted is made based on the plasma detection threshold VP. Here, when it is predicted that plasma is generated, measures such as reducing the cutting processing speed are performed by the processing machine control drive unit and the processing condition control unit 60 (step S140), thereby avoiding the generation of plasma.
[0032]
FIG. 5 is a flowchart showing a processing procedure of the laser processing apparatus that performs burst generation prediction according to the embodiment of the present invention. After step S140, the processing is continued in a state where the cutting speed of the workpiece 4 is reduced, and the reflected light from the workpiece 4 is continuously received. Here, the physical phenomenon of the burst may be shifted at a speed faster than the plasma generation suppression speed due to the reduction in the cutting speed.
[0033]
The burst detection threshold value VB is calculated as a judgment reference value for predicting the occurrence of a burst based on the plasma burst detection reference value VC and the plasma detection threshold value VP (step S200).
[0034]
Here, the calculation method of the burst detection threshold value VB is set in advance. For example, the value of the reflected light intensity when the reflected light intensity becomes 10 times the plasma burst detection reference value VC or 3 times the plasma detection threshold value VP is set to be the burst detection threshold value VB. . Further, the determination of whether or not the occurrence of a burst is predicted may be made based on the increasing / decreasing tendency of the reflected light. For example, it is predicted that a burst will occur when the rate of increase in reflected light intensity increases at a predetermined rate or more.
[0035]
Next, it is determined whether or not the value of the reflected light intensity is greater than the burst detection threshold value VB (step S210). In FIG. 4, the reflected light intensity reaches the burst detection threshold VB at time c, and it is predicted that a burst will occur here. As described above, whether or not a burst has occurred is determined based on the plasma burst detection reference value VC and the plasma detection threshold value VP.
[0036]
When the reflected light intensity value is larger than the burst detection threshold value VB and a burst is predicted to occur, the NC control unit processes the information instructed in block units by the NC program stored in the control unit 300. The unit is divided into interpolation units, and the machine value (coordinate value of the machining head 11 with respect to the workpiece 4) in this interpolation unit is stored in the position storage unit. Further, the sequence state (assist gas conditions necessary for processing, etc.) at this time is stored in interpolation units by the sequence state storage unit (step S220).
[0037]
Thereafter, the laser processing apparatus is stopped (step S230). Note that there is a delay time from the stop control process of the normal laser processing apparatus to the actual stop of the laser processing apparatus. Here, when the recovery work of the laser processing apparatus is necessary, the operator of the laser processing apparatus performs the recovery work (step S240), and resumes the laser processing after the recovery work is completed.
[0038]
Even if the value of the reflected light intensity is smaller than the burst detection threshold VB, if the reflected light intensity is greater than the predetermined value (step S250), there is a possibility that normal processing has not been performed, and therefore step S220 and Similarly, the machine value and sequence state are stored in interpolation units (step S260). When the value of the reflected light intensity is smaller than the burst detection threshold value VB, it is not necessary to stop the laser processing apparatus, and the process is directly shifted to the reprocessing process.
[0039]
Next, the procedure of the rework process after the burst occurrence prediction (after the burst occurrence) will be described. FIG. 6 is a flowchart showing the procedure of the reprocessing process of the laser processing apparatus. In this reprocessing process, first, the processing path from the time when the burst is predicted to occur based on the machine value and sequence state acquired in step S220 or step S260 in FIG. 5 to the time when the laser processing apparatus is stopped is interpolated. And stored by the machining path storage unit.
[0040]
Normally, the control unit 300 can manage the machining path only in units of NC blocks. Therefore, the machining path (movement information) for the workpiece 4 of the machining head 11 in the currently executed block is divided into interpolation units as internal coordinate values. Generate and manage.
[0041]
For this reason, when one block process is completed, the control unit 300 manages only the internal coordinate value of the block to be processed next. On the other hand, in the embodiment of the present invention, even when the processing path from the time when the burst is predicted to the time when the laser processing apparatus is stopped straddles between blocks from one block to another block. The internal coordinate values in the block immediately before the block where the laser processing apparatus is stopped are also generated again.
[0042]
As described above, the machining conditions from the time when the burst is predicted to occur (when the burst detection threshold VB is detected) to the stop of the laser machining apparatus are calculated again in units of interpolation information (step S300). Further, the machining path calculation unit 80 recalculates the machining conditions and the like for performing the re-machining process from the position where the abnormal machining process has occurred (step S305).
[0043]
Here, the relationship between the beam diameter and the beam spot diameter, which is one of the processing conditions, will be described. FIG. 7 is a diagram for explaining the relationship between the beam diameter output from the laser oscillation unit 200 and the beam spot diameter irradiated from the tip of the processing head 11. In FIG. 7, the beam diameters Φ1 and Φ2 represent the diameter dimensions of a beam (hereinafter referred to as an output beam) output from the laser oscillation unit 200 to the processing head 11, and the beam spot diameters φ1 and φ2 are the tips of the processing head 11. The diameter dimension of a beam (hereinafter referred to as an irradiation beam) irradiated from the portion to the workpiece 4 is shown.
[0044]
The lens 3 is installed inside the machining head 11, and collects the output beam to change the beam diameter Φ1 of the output beam to the beam spot diameter φ1 of the irradiation beam, and the beam diameter Φ2 of the output beam to the irradiation beam. The lens 3 has a beam spot diameter φ2, and the lens 3 decreases the beam spot diameter of the irradiation beam as the beam diameter of the output beam increases. Here, the relationship of (beam spot diameter φ1) <(beam spot diameter φ2) is established with respect to the relationship of (beam diameter φ1)> (beam diameter φ2). Therefore, in order to reduce the beam spot diameter of the irradiation beam on the workpiece 4, it is necessary to increase the beam diameter of the output beam, and in order to increase the beam spot diameter of the irradiation beam on the workpiece 4, the output beam It is necessary to reduce the beam diameter.
[0045]
In step S300, after recalculating the interpolation information from when the burst is predicted to occur until the stop of the laser processing apparatus, laser beam processing is performed by increasing the beam diameter in order to avoid duplicate processing of the workpiece 4. The beam spot diameter is controlled to be small (step S310). And the process which reversely progresses the process path | route from when it is estimated that a burst generate | occur | produces in the state which made the beam spot diameter small until a laser processing apparatus stops is started (step S320).
[0046]
In addition, the laser processed part that was laser processed during normal processing and the part that was laser processed when the occurrence of a burst was predicted had different processing cut widths, so the reflected light when traveling backward through the processing path was monitored. As a result, the position where the abnormal processing has occurred is accurately found (step S330).
[0047]
FIG. 8 is a diagram for explaining the process of reversing the machining path and the beam spot diameter when resuming the machining. In FIG. 8, a portion h of the workpiece 4 indicates a portion that has been subjected to normal machining processing, and indicates that a burst has occurred in the vicinity of the portion i of the workpiece 4. A portion j of the workpiece 4 indicates a portion that has been processed until the laser processing apparatus actually stops after the occurrence of the burst (after the prediction of the occurrence of the burst). That is, in the normal processing, the processing head 11 is fixed and the workpiece 4 moves from the right to the left (the negative direction of the Y axis) in the drawing, and the processing is performed in order from the left portion to the right portion of the workpiece 4. The
[0048]
On the other hand, in the process of reversing the machining path, the machining head 11 is fixed and the workpiece 4 moves from the right to the left (the Y axis plus direction) in the drawing. Here, since the reflected light intensity is monitored while performing the process of proceeding in the reverse direction of the machining path, it is possible to accurately detect the boundary position between the part that has been processed normally and the part that has been processed abnormally. .
[0049]
In addition, there is a portion where normal processing has been performed after the laser processing apparatus is actually stopped after it is predicted that a burst will occur. In the process of proceeding in the reverse direction of the machining path, the workpiece 4 is moved by changing the beam spot diameter to be smaller than that when the part h of the workpiece 4 (the part where the normal machining process has been performed) is processed. As a result, even if the machining head 11 passes through the part that has been subjected to the normal machining process while reversing the machining path, it is possible to avoid overlapping machining of the part that has undergone the normal machining process.
[0050]
Then, after reversing the machining path, the beam spot diameter is returned from the boundary position between the normally machined portion and the abnormally machined portion detected by monitoring the reflected light intensity to the beam spot diameter where normal processing is performed (step S340). ), The processing is resumed (step S350).
[0051]
In the present embodiment, the case where the same light receiving unit 1 is used for plasma detection and burst detection has been described. However, plasma detection and burst detection are performed so that the light wavelength generated by processing is limited. Separate light receiving portions 1 may be provided.
[0052]
In the present embodiment, the case where the light receiving unit 1 is provided above the processing head 11 has been described. However, if the light receiving unit 1 is in the vicinity of the optical path of the laser beam, the light receiving unit 1 is provided in the tip of the processing head 11 or in the laser oscillation unit 200. Also good.
[0053]
Further, in the present embodiment, a case has been described in which reprocessing is performed by reversing the processing path when plasma generation or burst generation is predicted. However, when plasma is actually generated or burst occurs. Sometimes, the rework process may be performed by reversing the machining path.
[0054]
As described above, according to the embodiment, plasma generation and burst generation are predicted without using the threshold database, so that accurate plasma generation and burst generation can be predicted without being affected by the material and thickness of the workpiece 4. It can be carried out. In addition, in order to accurately predict plasma generation and burst generation based on reflected light during normal processing after the start of processing processing, even if the components of the light receiving unit 1 are replaced, the effects of component replacement are affected. The generation of plasma can be predicted. Furthermore, after the laser processing apparatus is stopped due to the predicted burst occurrence, the internal coordinate values in the block immediately before the block where the laser processing apparatus stopped are also generated again. Even when the machining path up to the stop of the machining apparatus spans from one block to another, it is possible to accurately perform the rework process from the position where the abnormal machining process has occurred. .
[0055]
【The invention's effect】
As described above, according to the present invention, in order to predict plasma generation and burst generation based on reflected light during normal processing after the start of processing, when component parts are replaced or processed Even if the material and the plate thickness of the object are different, there is an effect that the plasma generation and the burst generation can be accurately predicted. Furthermore, after the laser processing apparatus is stopped due to the predicted occurrence of a burst, the internal coordinate values in the block immediately before the block where the laser processing apparatus stopped can be generated again, so that the burst is predicted to occur. Even if the machining path from when the laser machine is stopped to when the laser machining apparatus is stopped extends from one block to another, it is possible to accurately perform the re-machining process from the position where the abnormal machining process has occurred. There is an effect that it becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a laser processing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a reflected light detection unit of a laser processing apparatus.
FIG. 3 is a flowchart showing a processing procedure of a laser processing apparatus that performs plasma generation prediction.
FIG. 4 is a diagram showing the intensity of reflected light from a workpiece observed during laser processing.
FIG. 5 is a flowchart showing a processing procedure of a laser processing apparatus that performs burst generation prediction.
FIG. 6 is a flowchart showing a re-processing procedure of the laser processing apparatus.
FIG. 7 is a diagram showing the relationship between the beam diameter output from the laser oscillation unit and the beam spot diameter irradiated from the tip of the processing head.
FIG. 8 is a diagram for explaining a beam spot diameter when processing is resumed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light-receiving part, 2 Detection processing part, 3 Lens, 4 Workpiece, 10 Reflected light detection part, 11 Processing head, 12 Processing table, 13 Z-axis motor, 20 Z-axis motor, 21 Beam correction part, 30 Control apparatus main body , 40 Reflected light determination unit, 41 Reference light determination unit, 42 Threshold generation unit, 50 Processing machine drive unit, 60 Processing condition control unit, 70 Storage unit, 71 Position storage unit, 72 Processing path storage unit, 73 Sequence state storage unit 80 machining path calculation unit, 100 machining processing unit, 200 laser oscillation unit, 300 control unit.

Claims (10)

A laser oscillation unit that outputs a laser; a processing unit that processes a workpiece by a processing head that irradiates laser light from the laser oscillation unit; a detection unit that detects reflected light from the workpiece; In a laser processing apparatus comprising a laser oscillation unit and a control unit that controls the processing unit,
The controller is
A reference light determining unit that sets a reference value for each processing process for predicting the generation of plasma based on reflected light at the time of normal processing after the start of the processing process;
A plasma threshold value generator for calculating a threshold value for predicting plasma generation based on the reference value;
Plasma generation is predicted based on a comparison between the intensity of reflected light from the detection unit and a threshold value for predicting the plasma generation, and when it is determined that the plasma is generated, the processing conditions of the workpiece are changed. A processing condition changing unit for controlling the laser oscillation unit and / or the processing unit;
A laser processing apparatus comprising: The laser processing apparatus according to claim 1, wherein the plasma threshold generation unit calculates a threshold for predicting generation of plasma based on the reference value and an increase rate of reflected light intensity. The control unit, a burst threshold generation unit that calculates a threshold for predicting the occurrence of a burst that is a blow-up phenomenon after processing failure occurs due to plasma based on the reference value;
A burst occurrence prediction unit that predicts burst occurrence based on a comparison between the reflected light intensity from the detection unit and a threshold value for predicting the burst occurrence;
The laser processing apparatus according to claim 1, further comprising: The laser processing apparatus according to claim 3, wherein the burst threshold generation unit calculates a threshold for predicting occurrence of a burst based on the reference value and an increase rate of reflected light intensity. The control unit stores a position predicted by the burst occurrence prediction unit that a burst is generated,
A machining path storage unit that stores a machining path after the position where the occurrence of the burst is predicted to occur, and
When the burst occurrence prediction unit predicts that a burst will occur, control is performed to reverse the machining path based on the position where the occurrence of the burst is predicted and the machining path. Item 5. The laser processing apparatus according to Item 3 or 4. The said processing path memory | storage part divides | segments and memorize | stores the said processing path | route into the interpolation unit which is the minimum unit of the information commanded from a control part, It is characterized by the above-mentioned. Laser processing equipment. The control unit detects a position where the abnormal machining process has occurred while reversing the machining path, calculates information for performing a new machining process using the detected position where the abnormal machining process has occurred, 7. The laser oscillation unit and the processing unit are controlled so as to resume the processing from the position where the abnormal processing has occurred based on information for performing a new processing. The laser processing apparatus as described in any one. The information for performing the new processing is calculated by being divided into interpolation units, which are minimum units of information commanded from the control unit. The laser processing apparatus as described. The said control part detects the position which the abnormal machining process generate | occur | produced based on the reflected light intensity detected while reverse | reversing the said process path | route, The any one of Claims 3-8 characterized by the above-mentioned. Laser processing equipment. The control unit controls the laser of the laser oscillation unit so as to reduce a beam spot diameter of a laser that processes the workpiece after the processing path is reversed and the processing is resumed. The laser processing apparatus according to any one of claims 3 to 9.

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