JP4741914B2 - Laser cutting method - Google Patents

Description

  The present invention recognizes the base material temperature of a portion to be cut while irradiating laser light toward the material to be cut and injecting an assist gas to cut the material to be cut, and cutting according to the recognized temperature. The present invention relates to a laser cutting method in which burning can be prevented by continuing, stopping cutting, or cooling the periphery of a portion to be cut.

  A laser cutting method may be employed when cutting a metal workpiece. In this laser cutting method, a laser cutting nozzle irradiates a laser beam from a laser cutting nozzle toward a material to be cut and injects an assist gas to evaporate or melt the base material, and eliminates the evaporated material and the molten material. And a material to be cut are moved relatively to form a continuous groove and cut.

  In particular, when the material to be cut is an iron-based metal, it is common to use high-purity oxygen gas as an assist gas in order to achieve good cutting. In other words, the laser beam is ejected from the injection port formed at the center of the laser cutting nozzle toward the material to be cut together with the assist gas made of oxygen gas, so that the base material at the portion irradiated with the laser beam is burned and assisted. By evaporating the gas, the evaporated material, the molten base material, the molten oxide and the like are removed from the base material to form a continuous groove, thereby cutting the material to be cut.

  When laser cutting iron-based metals, when the balance of laser output, cutting speed, assist gas flow rate, etc. is lost, a phenomenon called burning occurs in which the base metal near the irradiated portion of the laser beam melts or burns. When this phenomenon occurs, there arises a problem that uncontrollable depressions are generated around the planned cutting line and the quality of the cut surface is deteriorated. For this reason, several techniques for detecting the occurrence of burning have been proposed.

  For example, the technique described in Patent Document 1 measures the amount of light from an image of the surface of a material to be cut photographed through a nozzle by a CCD camera arranged inside a laser torch, and uses the measured amount of light as the current processing content (cutting). Or piercing), it is possible to determine whether or not the target processing is performed smoothly by comparing with a standard light amount value set in advance. Therefore, when the target processing is cutting, when the measured light quantity is larger than a preset light quantity, it is recognized that burning has occurred, and a signal indicating an abnormal cutting state is generated. .

JP-A-11-320149

  Since the above technique is used to determine whether the current cutting is normally performed or whether burning has occurred, when the occurrence of burning has been detected, the cutting is quickly stopped and the workpiece is cut. It is possible to minimize the problems that occur. However, since the product becomes defective at the same time as the burning occurs, the occurrence of the defect cannot be prevented even if the occurrence of the burning can be detected. For this reason, development of a laser cutting method in which burning does not occur during cutting is required.

  The object of the present invention is to recognize the possibility of burning by recognizing the temperature around the cutting site in the material to be cut during the progress of laser cutting. The object is to provide a laser cutting method capable of preventing burning by taking measures.

  The inventor of the present invention is pursuing a mechanism of occurrence of burning in laser cutting. As a result, it was confirmed that one of the causes when burning occurred was an increase in the temperature of the material to be cut.

  Usually, cutting specifications such as a cutting speed for a material to be cut having a specific material and plate thickness are set on the assumption that the material to be cut is in an atmospheric temperature state (cold). However, the speed at which cutting is possible increases as the temperature of the material to be cut increases. That is, the cutting performance of the material to be cut increases as the base material temperature increases. For this reason, in the material to be cut whose base material temperature has increased, the periphery of the material to be cut easily burns, and if it is cut at the cutting speed for the material to be cut in the cold state, it can be cut relatively. Cutting is slower than the speed.

  As described above, the balance between the cutting speed and the cutting performance of the material to be cut is lost, and burning occurs accordingly.

  Burning occurs on the surface of the material to be cut. That is, it occurs very easily when the surface temperature of the material to be cut rises above the temperature at which burning is likely to occur. Therefore, it is possible to prevent the occurrence of burning by recognizing how the surface temperature of the material to be cut is related to the temperature at which burning is likely to occur.

Therefore, the laser cutting method according to the present invention, when cutting the該被cutting material by ejecting an assist gas irradiates laser light toward the workpiece, near of the cleavage site in the workpiece Is a laser cutting method of cutting the part to be cut after recognizing the temperature of the material, cutting the material to be cut in advance to obtain the plate thickness and material, the shape of the figure to be cut, the cutting time, and the cutting of the material Measuring the temperature of the material to be cut according to the cutting conditions including, recognizing the temperature measured in advance according to the cutting conditions for the material to be cut as the temperature in the vicinity of the site to be cut in the material to be cut; and precut stop temperature to stop the cut for the material to be cut, or may be set the cutoff start temperature for starting the cut for the workpiece, when it recognizes a temperature in the vicinity of the target cleavage sites in the workpiece, the Recognized temperature stops cutting Is higher than degrees, to start the cut with respect to the cutting member when the cutting for cutting material is stopped to cool by spraying cooling fluid to the cutting object, recognized temperature is lower than the cutoff start temperature It is characterized by.

Above chelating chromatography The cutting method, since the cut after recognizing the temperature in the vicinity of the cleavage site in the workpiece, if such there is a possibility that the temperature in the vicinity of the cleavage site generates a high burning Can stop cutting. For this reason, burning does not occur.

Also, by executing the cutting with respect to advance the cutting object, the plate thickness and material, the shape of the graphics to be cut, the cutting time, by measuring the temperature of the workpiece according to the cutting conditions including the blank layout for the material to be cut By setting it, the temperature of the material to be cut corresponding to each of the above conditions can be assumed. Therefore, when the cutting conditions for the target material to be cut are set, the temperature near the portion to be cut in the target material to be cut can be predicted.

  For this reason, predicting according to the cutting conditions for the target material to be cut, recognizing the temperature as the temperature in the vicinity of the part to be cut, and determining whether the recognized temperature is a temperature at which burning may occur. Can do. Therefore, by cutting the target material to be cut based on the above determination or by stopping the cutting, it is possible to make a good laser cutting without causing burning.

Also, in advance based on the temperature that a possibility that burning occurs, may be set the cutoff start temperature for starting the cut for cutting stop temperature, or workpiece stops cut against the cutting object, the cutting of the object When recognizing the temperature in the vicinity of the part to be cut in the material, if the recognized temperature is higher than the cutting stop temperature, the cutting of the cut material is stopped, or the cut is made when the recognized temperature is lower than the cutting start temperature. By starting the cutting of the material, a good laser cutting can be advanced without causing burning.

Further, in the forced cooling to isosamples injecting cooling fluid to stop the cutting to the cutting object, without causing burning, it is possible to proceed with good laser cutting.

  The best mode of the laser cutting method according to the present invention will be described below. The laser cutting method according to the present invention recognizes the temperature in the vicinity of the part to be cut in the material to be cut when laser cutting the material to be cut, and continues or stops the cutting in accordance with the recognized temperature. By smoothing or forcibly cooling, smooth cutting can be performed without causing burning.

  Burning occurs from the surface of the material to be cut. For this reason, the temperature of the material to be cut for determining whether or not burning occurs may be the surface temperature of the material to be cut. Therefore, by preliminarily measuring the temperature at which burning occurs and recognizing the surface temperature of the material to be cut, by determining whether the recognized temperature is above or below the temperature at which burning occurs, It is possible to determine whether or not burning is likely to occur.

  As a method of recognizing the temperature of the material to be cut, there is a method of measuring using a thermometer such as an infrared thermometer. This method is preferable because it is possible to recognize the surface temperature of the material to be cut near the actual cut site with high reliability. However, in this method, there may be a case where an accurate temperature cannot always be measured depending on the state of the surface of the material to be cut.

  Other methods for recognizing the temperature of the material to be cut include what type of cutting is being performed on the material to be cut, or what type of cutting has been performed on the material being cut. The material to be cut burns by examining the cutting schedule or cutting results such as what kind of cutting has already been made in the vicinity of the cutting line inside and what time has passed since the cutting was made. It is also possible to recognize whether there is a possibility of reaching the temperature or whether the material to be cut has reached the burning temperature.

  As described above, in order to recognize the temperature of the material to be cut according to the cutting schedule or the actual cutting result, various shapes of the material to be cut are cut, and the temperature of the material to be cut with time in the vicinity of the cutting line. It is possible to measure the change and obtain a value that can exhibit reliability from the measurement result.

  For example, when a straight cut is performed on the material to be cut, the heat of the cut portion of the material to be cut is transmitted to the surroundings substantially evenly during the cutting, thereby raising the temperature of the material to be cut. At the same time, since the material to be cut is cooled by the atmosphere, the temperature in the vicinity of the cut portion is highest at the cut portion, becomes lower as it is separated from the cut portion, and falls with time.

  Therefore, it is possible to measure the temperature distribution corresponding to the distance from the cut portion in the material to be cut in advance and the temperature distribution corresponding to the elapsed time after the end of cutting. And, when trying to cut the material to be cut, if the cutting target line and the cutting material have already been cut, the temperature near the planned cutting line is set based on the temperature distribution from the already cut line. It is possible to recognize.

  When cutting a curved line (especially a circle) or a corner (especially an acute angle) with respect to the material to be cut, the center side of the circle and the acute angle side of the corner are separated from the base material as the cutting progresses, so the heat capacity is high. Get smaller. For this reason, it rises to a high temperature in a very short time, and as a result, the temperature of the part to be cut will rise during the cutting of a circle or an acute angle.

  Therefore, when a circle or an acute angle exists in the planned cutting line, it can be recognized as an extremely high temperature (a temperature at which burning is likely to occur) in the vicinity of these planned cutting lines.

  In the experiments of the present inventors, for example, when the material to be cut is a steel plate, the temperature at which burning occurs is about 70 ° C. Further, when the planned cutting line is a circle having a diameter of about 20 mm or less, the material to be cut rises to a temperature at which burning occurs while the circle is being cut. In addition, even when the planned cutting line has an acute angle of about 45 degrees or less, the material to be cut rises to a temperature at which burning occurs during the cutting.

  Further, when there is a line that has already been cut with respect to the material to be cut, the temperature within a range of 5 mm from the already cut line is the air cooling time that is cooled by the atmosphere after the cutting with respect to the already cut line is completed. In 10 minutes or less, it is not cooled to a temperature sufficiently lower than the temperature at which burning is generated, and it is cooled to a sufficiently low temperature when 10 minutes have elapsed.

  Therefore, when the planned cutting line exists within 5 mm from the existing cutting line (including the case where the planned cutting line crosses the existing cutting line), an attempt is made to cut the planned cutting line within 10 minutes after the completion of the cutting of the existing cutting line. Then, there is a possibility that burning will occur.

  Further, when the material to be cut is subjected to drilling (piercing) by a laser torch, the temperature in the range of about 10 mm radius from the piercing point is lower than the temperature at which burning occurs within 10 minutes after the end of piercing. However, it is not cooled to a sufficiently low temperature, and it is cooled to a sufficiently low temperature when 10 minutes have passed.

  Further, in the experiments of the present inventors, the temperature of the material to be cut that is likely to cause burning is a substantially constant temperature, although there are some differences depending on the material, and the temperature of the material to be cut exceeds the temperature at which burning occurs. Burning is likely to occur, and burning is less likely to occur below the temperature at which burning occurs.

  Therefore, it is preferable to experimentally measure the temperature at which burning occurs in the material to be cut in advance, and set the cutting stop temperature, cutting start temperature, and forced cooling temperature based on the measured temperatures. Since the temperature at which burning measured experimentally is a temperature at which burning is surely generated on the workpiece, cutting should not be performed on the workpiece. That is, the temperature at which the burning occurs is a temperature at which cutting should be stopped, and may also serve as a forced cooling temperature. Further, a temperature lower than the temperature at which the burning occurs is the cutting start temperature.

  The cutting stop temperature does not necessarily need to coincide with the temperature at which burning occurs, and it is preferable to set a temperature lower by about 5% to 10% than the temperature as the cutting stop temperature. Thus, by stopping cutting at a temperature lower than the temperature at which burning occurs, it is possible to reliably prevent the burning from occurring.

  The cutting start temperature is preferably set so that it is at least 10% to 20%, preferably about 50% lower than the temperature at which burning occurs, and does not share the same temperature as the cutting stop temperature. Thus, stable cutting can be continued by setting the cutting start temperature to a temperature sufficiently lower than the temperature at which burning occurs.

  Further, the forced cooling temperature does not necessarily need to coincide with the temperature at which burning occurs, and can be set as appropriate. For example, when the forced cooling temperature is set to coincide with the temperature at which burning occurs, or when it is set to coincide with the cutting stop temperature, the material to be cut is stopped in a state where cutting to the material to be cut is stopped. It is possible to forcibly cool.

  When performing forced cooling on the material to be cut, without measuring the temperature of the material to be cut accompanying the forced cooling, by performing forced cooling for a preset time, the material to be cut dropped to the cutting start temperature, It is preferable that it can be recognized as. By performing the forced cooling operation in terms of time, it is possible to reliably resume the cutting of the workpiece.

  For this reason, while setting the device for forced cooling, measure the temperature drop of the material to be cut due to the operation of the device, and cut from the start of operation of the forced cooling device after the material to be cut reaches the forced cooling temperature It is preferable to set a sufficiently reliable time to drop to the starting temperature.

  As an apparatus for forced cooling, it is possible to use, for example, a device in which a nozzle is arranged around a laser torch and a cooling medium can be ejected from the nozzle toward a material to be cut. The cooling medium may be any material that can cool the material to be cut, and a fluid such as cooling water, compressed air, or an inert gas containing nitrogen gas can be selectively used.

  Next, examples of the present invention will be described. In this embodiment, the means for recognizing the temperature in the vicinity of the part to be cut in the material to be cut is a temperature set based on the distance from the cutting part and the elapsed time measured in advance by experiments. Further, based on the temperature at which burning was measured in advance, which was measured in advance, the cutting stop temperature at which cutting of the material to be cut was stopped was set as a temperature about 15% lower than the temperature at which burning occurred. The cutting start temperature at which cutting of the material to be cut was started was set as a temperature approximately 45% lower than the temperature at which burning occurs. The forced cooling temperature at which the material to be cut was forcedly cooled was set to a temperature that was approximately 15% lower than the temperature at which burning occurred. This forced cooling temperature is set as the same temperature as the cutting stop temperature.

  First, when the temperature at which burning occurs in the material to be cut was experimentally measured, it was about 70 ° C. to about 90 ° C. regardless of the thickness of the steel plate and the stainless steel plate. For this reason, the temperature at which burning occurs is set as 70 ° C., the cutting stop temperature and the forced cooling temperature are set as 60 ° C. lower by about 15% with reference to this temperature, and the cutting start temperature is lowered by about 45% 40 Set as ° C.

  Further, after the material to be cut was linearly cut, the temperature of the part separated from the cut portion (the upper edge of the cut surface) and the change in temperature with the passage of time were measured. In this case, the severest temperature condition is the cut portion itself. Also, when cutting the vicinity of the once cut part again, except for the case of crossing the already cut line, the position closest to the already cut line is 5 mm, and no further approach (for example, 3 mm) will occur. The change in temperature at a position 5 mm away from the cut part was measured.

  As a result, at this position, the room temperature is maintained until cutting is started, the temperature rises immediately after the end of cutting, and the highest temperature is about one and a half minutes after the end of cutting. Yes, the temperature at this time reached about 75 ° C. Thereafter, the temperature gradually decreased, reaching about 65 ° C. after 8 minutes and reaching about 60 ° C. after 10 minutes.

  Therefore, in this embodiment, when the already cut line is a straight line, it is recognized as a temperature corresponding to the cutting stop temperature and the forced cooling temperature until 10 minutes have passed at a position 5 mm from the already cut line. And after 10 minutes have passed, it recognizes as a temperature corresponding to the temperature which can be cut | disconnected also in the position 5 mm away from the already cut line.

  Further, after piercing the material to be cut, the temperature of the part separated from the piercing point and the change in temperature with the passage of time were measured. The piercing operation is a harsh operation that applies a lot of heat because the laser beam is irradiated onto the material to be cut and the assist gas is injected while the laser torch is stopped. For this reason, the change in temperature at a position 10 mm away from the piercing point was measured.

  As a result, at the above position, the room temperature is maintained until piercing is started, the temperature gradually increases from the start of preheating of the piercing, and the temperature reaches about 70 ° C. almost simultaneously with the end of the piercing. did. Thereafter, the temperature gradually decreased, reaching about 65 ° C. after 8 minutes and reaching about 60 ° C. after 10 minutes.

  Therefore, in this embodiment, it is recognized as a temperature corresponding to the cutting stop temperature and the forced cooling temperature until 10 minutes have passed at a position where the distance from the piercing point is 10 mm. And after 10 minutes have passed, it is recognized as the temperature corresponding to the cuttable temperature.

  In addition, when the planned cutting line for the material to be cut was a circle and two sides having acute corners, cutting was performed to measure the temperature at the center of the circle, the temperature inside the corner, and the temperature drop. As described above, on the center side of the circle and the inside of the corner, a piece having a small heat capacity is formed as the cutting progresses, resulting in severe cutting.

  As a result, it has been found that a circle with a diameter of 20 mm or less or an acute angle with an angle of 45 degrees or less exceeds 70 ° C., which is the temperature at which burning occurs during cutting. For this reason, when the planned cutting line is the circle or the acute angle, it is recognized as a temperature corresponding to the cutting stop temperature and the forced cooling temperature when cutting to approximately half the position of the circle and one side of the acute angle. Furthermore, after the above-described circle or acute angle is cut, it is handled in the same manner as when the already cut line is a straight line.

  As described above, in this embodiment, considering the positional relationship between the planned cutting line set for the material to be cut and the previous cutting line within the past 10 minutes with respect to the planned cutting line, The temperature is recognized as the temperature corresponding to the cutting stop temperature and the forced cooling temperature, and is recognized as the temperature corresponding to the cutting possible temperature at other portions.

  Next, an example of an apparatus for performing the laser cutting method according to the present invention will be briefly described with reference to the drawings. FIG. 1 is a diagram schematically illustrating the configuration of a laser cutting device. FIG. 2 is a diagram illustrating an example of a cooling device that forcibly cools a material to be cut. FIG. 3 is a block diagram of a control system of the laser cutting device.

  The laser cutting device A shown in FIG. 1 is a cutting device controlled by a numerical control (NC) device, and after storing a program of a planned cutting line for the material to be cut B in advance, by executing this program, It is comprised so that a desired shape can be cut | disconnected.

  In the figure, the laser cutting device A comprises a saddle 2a placed on a pair of rails 1 laid in parallel and two garters 2b, 2c arranged in a direction orthogonal to the rails 1. The frame 2 is configured by connecting the saddle 2a and the garters 2b and 2c, the traveling motor 3 is attached to the position corresponding to the rail 1 of the saddle 2a, and the laser oscillator 4 is mounted on the upper portion of the garter 2c. is doing.

  A laser beam path 5 is formed starting from the emission port 4a of the laser oscillator 4. This laser beam path 5 is formed between the laser oscillator 4 and the laser torch 7, and the position of the laser torch 7 in the frame 2 Regardless, an inversion mirror 6 is provided for maintaining a constant distance between the laser torch 7 and the laser oscillator 4.

  The laser torch 7 is mounted on a carriage 8 provided so as to be capable of traversing along the garter 2 b constituting the frame 2. Therefore, by controlling the rotation of the traverse motor 9 provided on the carriage 8, it is possible to traverse in the direction orthogonal to the rail 1 along the garter 2b.

  Since the carriage 8 is configured to traverse along the garter 2b, the laser beam path 5 is also configured using the garter 2b. That is, the laser beam path 5 returns from the laser platinum existing exit 4a along the garter 2b in the opposite direction of the laser oscillator 4 and is inverted by the inverting mirror 6 and again along the garter 2b along the exit 4a of the laser oscillator 4. It is configured to be able to enter the laser torch 7 after changing its direction to

  In the laser light path 5 configured as described above, the mirrors 10a to 10c are provided at the portions where the direction is changed, and the reversing mirror 6 is provided with a pair of mirrors 6a and 6b at opposing positions. The reversing mirror 6 is configured to move along the garter 2b with a movement amount ½ of the movement amount of the carriage 8.

  A cover 11 made of an expandable bellows or a cylindrical body is disposed in a linear portion from the exit 4a of the laser oscillator 4 to the laser torch 7 in the laser light path 5, and the laser light is exposed by the cover 11. And dust in the air is prevented from entering the laser beam path 5.

  The control panel 12 incorporates an NC device for controlling the laser cutting device A. The input device 13 including a keyboard and switches provided on the operation panel 12a and the display 14 are used for the material of the material B to be cut, After the material is taken by inputting information such as thickness and the figure to be cut, the control is started to sequentially control the emission of the laser light by the traveling motor 3, the transverse motor 9, and the laser oscillator 4. It is possible to perform the cutting | disconnection with respect to the to-be-cut material B by this.

  As shown in FIG. 2, a cooling nozzle 21 for cooling the material to be cut B is attached to the tip of the laser torch 7, and this cooling nozzle 21 is connected to an air compressor (not shown) via an electromagnetic valve 22. Has been. Therefore, by controlling the opening and closing of the electromagnetic valve 22, the compressed air is jetted toward the material to be cut B, whereby the vicinity of the laser torch 7 in the material to be cut B, that is, in the material to be cut B. It is possible to forcibly cool the vicinity of the cutting site.

  Next, the control system of the laser cutting apparatus A will be described with reference to the block diagram of FIG.

  In the figure, reference numeral 31 denotes a control device, and a thickness of the processing part 31a, a program storage part 31b in which a preset cutting program is written, and a workpiece B input from the input device 13 And a temporary storage unit 31c for temporarily storing data such as cutting conditions.

  Reference numeral 32 denotes a temperature recognition unit for recognizing the temperature of the material to be cut B, and the reference for recognizing the temperature in the material to be cut B described in the first embodiment (that is, when the already cut line is a straight line, It is recognized as a temperature corresponding to the cutting stop temperature and the forced cooling temperature until 10 minutes have passed at a position 5 mm from the already cut line, and after 10 minutes have passed, it can be cut even at a position 5 mm away from the already cut line. Recognized as a temperature corresponding to the temperature, after the piercing is performed, at a position where the distance from the piercing point is 10 mm, it is recognized as a temperature corresponding to the cutting stop temperature and the forced cooling temperature until 10 minutes have passed. After a minute has passed, the point is recognized as the temperature corresponding to the temperature that can be cut, and when the planned cutting line is a circle with a diameter of 20 mm or less, or an acute angle with an angle of 45 degrees or less, it is cut to about half the circle and one side of the acute angle. When The temperature is recognized as the temperature corresponding to the cutting stop temperature and the forced cooling temperature, and thereafter the point that is recognized in the same manner as in the case where the already cut line is a straight line) is stored, and cutting is performed with the operation of the laser cutting device A. Coordinate data at a position 5 mm away from the already cut line is sequentially stored for 10 minutes, and compared with the coordinate data of the current laser torch 7, the coordinate data of the vicinity of the current laser torch 7 on the workpiece B is compared. It has a function of recognizing temperature.

  In the laser cutting apparatus A configured as described above, a program for a figure to be cut from the material to be cut B is stored in the program storage unit 31b, and the thickness and cutting speed of the material B to be cut from the input device 13 are cut. When the information is input and operated, the laser torch 7 moves to the piercing point in the material B to be cut according to the cutting program, and at the same time, the temperature recognizing unit 32 is positioned 10 mm apart from the piercing point. Integration of coordinate data and time.

  When the piercing for the workpiece B is completed, the laser torch 7 moves from the piercing point onto the target graphic and starts cutting. Along with the cutting of the target graphic, the temperature recognition unit 32 stores the coordinate data at positions separated by 5 mm on both sides from the cut portion. Therefore, the position of the coordinate data stored in the temperature recognition unit 32 is such that the current temperature is recognized as the cutting stop temperature and the forced cooling temperature. Therefore, when the coordinate data of the scheduled cutting line read from the program storage unit 31b overlaps the coordinate data stored in the temperature recognition unit 32, the temperature in the vicinity of the scheduled cutting line in the material to be cut B is cut. It will be recognized as the stop temperature and the forced cooling temperature.

  When it is recognized that the temperature in the vicinity of the scheduled cutting line is the cutting stop temperature and the forced cooling temperature, the drive signals from the control device 31 to the traveling motor 3, the traversing motor 9, and the laser oscillator 4 are stopped, and the laser torch 7 is in the original position. Hold. Further, an opening signal is output to the electromagnetic valve 22, the electromagnetic valve 22 is opened, and compressed air is jetted from the cooling nozzle 21 toward the material to be cut B so as to face the laser torch 7 on the material to be cut B. Forcibly cool.

  Furthermore, when the laser torch 7 is stopped and the elapsed time of the coordinate data stored in the temperature recognition unit 32 that overlaps the coordinate data of the scheduled cutting line becomes 10 minutes, the scheduled time on the material B to be cut Recognizing that the temperature in the vicinity of the cutting line is the cutting start temperature, the control device 31 outputs a drive signal to the traveling motor 3, the traverse motor 9, and the laser oscillator 4, and the laser torch 7 cuts the planned cutting line. Resume. Further, the open signal that has been output to the electromagnetic valve 22 is stopped, the electromagnetic valve 22 is closed, and the injection of compressed air from the cooling nozzle 21 is stopped.

  The coordinate data stored in the temperature recognizing unit 32 is sequentially deleted when 10 minutes have elapsed since the start of storage. That is, the position 10 mm away from the piercing point with respect to the material to be cut B and the position 5 mm away from the cut portion are affected by the temperature associated with piercing or cutting after 10 minutes have passed after cutting. If it disappears, it will be recognized as a cutting start temperature. Accordingly, the cutting of the workpiece B is continued without stopping the laser torch 7.

  In addition, when the planned cutting line read from the program storage unit 31b has a circle with a diameter of 20 mm or less or an acute angle with an angle of 45 degrees or less, the circle and the acute angle are recognized on the program, and the half of the circle and the acute angle When one side is cut, it is recognized as the cutting stop temperature and the forced cooling temperature. As a result, the movement of the laser torch 7 is stopped and the operation of the laser oscillator 4 is stopped. The compressed air is injected from the cooling nozzle 21 to forcibly cool the material B to be cut. Then, after 10 minutes have passed since the laser torch 7 stopped, the laser torch 7 is restarted and cutting is resumed.

  The laser cutting method of the present invention configured as described above is advantageous in that it is possible to prevent the occurrence of burning and perform smooth and stable cutting without actually measuring the temperature of the material to be cut.

It is a figure which illustrates the structure of a laser cutting device roughly. It is a figure explaining the example of the cooling device which forcedly cools a to-be-cut material. It is a block diagram of the control system of a laser cutting device.

A Laser cutting device B Material to be cut 1 Rail 2 Frame 2a Saddle 2b, 2c Garter 3 Traveling motor 4 Laser oscillator 4a Emission port 5 Laser optical path 6 Reverse mirror 6a, 6b Mirror 7 Laser torch 8 Carriage 9 Traverse motor 10a-10c Mirror 11 Cover DESCRIPTION OF SYMBOLS 12 Control panel 12a Operation panel 13 Input device 14 Display 21 Cooling nozzle 22 Solenoid valve 31 Control apparatus 31a Calculation part 31b Program storage part 31c Temporary storage part 32 Temperature recognition part

Claims (1)

When cutting the該被cutting material by ejecting an assist gas irradiates laser light toward the workpiece, after recognizing the temperature in the vicinity of the cleavage site in the workpiece, the object cleavage site A laser cutting method for cutting
Cut the material to be cut in advance, measure the plate thickness and material, the shape of the figure to be cut, the cutting time, the temperature of the material to be cut according to the cutting conditions including the cutting for the material to be cut, and Recognizing the temperature measured in advance according to the cutting conditions as the temperature in the vicinity of the part to be cut in the cut material,
And the cutting stop temperature for stopping the cutting of the workpiece to be cut in advance, or the cutting start temperature for starting the cutting of the workpiece to be cut ,
When the temperature near the part to be cut in the material to be cut is recognized, if the recognized temperature is higher than the cutting stop temperature , the cutting of the material to be cut is stopped and the cooling fluid is injected to the material to be cut. The laser cutting method is characterized in that when the detected temperature is lower than the cutting start temperature, the cutting of the material to be cut is started .

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