JP2006346737A - Laser beam machine and laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a laser beam machine, which can eliminate adhesion of dross, requires no post-treatment for removing dross, and are excellent in productivity, and to obtain a laser beam machining method. <P>SOLUTION: The laser beam machine cuts an aluminum-made workpiece by irradiating the workpiece with a laser beam and supplying an assist gas to the workpiece. The laser beam machine comprises: a laser beam outputting means, which outputs the laser beam; an irradiating means, which guides the laser beam to the aluminum-made workpiece and irradiates the workpiece with the laser beam; an assist gas supplying means supplying, as an assist gas, a mixed gas of nitrogen and oxygen, in which mixing ratio of oxygen is 0.1-0.5 vol%, to the aluminum-made workpiece; and a control means for controlling cutting work in the laser beam machine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a laser processing apparatus and a laser processing method for efficiently laser processing aluminum.

  In general, in laser processing, there are appropriate types of assist gas and pressure depending on the type of material to be processed. That is, oxygen is used as an assist gas in processing mild steel, and nitrogen is used as an assist gas in stainless steel and aluminum processing to prevent discoloration due to oxidation of the cut surface. In the processing of titanium, it is preferable to use argon as an assist gas in order to prevent adhesion of dross (the melt residue adhering to the lower part of the cut surface).

JP 2001-239385 A

  By the way, in laser processing of aluminum, conventionally, air (air) or nitrogen is mainly used as an assist gas. When air is used as the assist gas, there is a problem that the cut surface becomes cloudy and a small amount of dross adheres. On the other hand, when nitrogen is used as the assist gas, a glossy cut surface can be obtained, but there is a problem that a large amount of dross adheres. In either case, a post-process for removing dross is necessary after laser processing, which causes a reduction in the efficiency of laser processing.

  Also, in conventional laser processing equipment, in order to improve cutting ability and cutting roughness while limiting oxidation of the cut surface in cutting of stainless steel, coated steel, aluminum or aluminum alloy, a mixed gas of oxygen and nitrogen Is used as an assist gas (see, for example, Patent Document 1). Patent Document 1 discloses that the oxygen content of the assist gas is more than 0 volume% and less than 8 volume%, preferably 150 ppm to 5 volume%.

  Here, the technique of the above-mentioned Patent Document 1 increases the cutting speed as compared with the cutting in the case of using 100% nitrogen as the assist gas, and in the cutting in the case of using 100% oxygen as the assist gas. The object is to reduce the surface roughness as compared with this, and in order to achieve this object, the effect can be obtained at an oxygen ratio in the above-mentioned range.

  However, the oxygen ratio shown in the above-mentioned Patent Document 1 cannot obtain an effect with respect to the problem of eliminating the adhesion of dross at the time of cutting in laser processing of aluminum. That is, the problem of dross adhesion at the time of cutting in laser processing of aluminum cannot be solved.

  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 and a laser processing method excellent in productivity that do not adhere dross and do not require a post-process for removing dross. And

  In order to solve the above-described problems and achieve the object, a laser processing apparatus according to the present invention irradiates an aluminum workpiece with a laser beam and supplies an assist gas to the aluminum workpiece. A laser processing apparatus for cutting a workpiece, a laser beam output means for outputting a laser beam, an irradiation means for directing and irradiating a laser beam to an aluminum workpiece, and a mixing ratio of oxygen as an assist gas An assist gas supply means for supplying a mixed gas of nitrogen and oxygen of 0.1 volume% to 0.5 volume% to the aluminum workpiece, and a control means for controlling the cutting process in the apparatus itself. It is characterized by providing.

  According to this invention, by using a mixed gas of nitrogen and oxygen with an oxygen concentration of 0.1 volume% to 0.5 volume% as the assist gas, dross at the time of laser processing of an aluminum workpiece It is possible to realize laser processing without adhesion. Thus, according to the present invention, it is possible to omit the process of removing the attached dross, which has been performed after laser processing in conventional laser processing, and to efficiently perform laser processing of an aluminum workpiece. There is an effect that it is possible.

  Embodiments of a laser processing method and a laser processing apparatus according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram schematically showing the overall configuration of the laser processing apparatus according to the first embodiment of the present invention. The laser processing apparatus according to the first embodiment supplies a laser oscillation unit 1 that oscillates a laser, a processing head 2, an optical unit 4 that includes a mirror, a lens, and the like, and changes the path of the laser, and an assist gas used during processing. Assist gas supply unit 8, assist gas adjustment unit 9 that adjusts the type and pressure of assist gas supplied to the machining head, control unit 11 that controls the entire apparatus, and machining table 12 that fixes the workpiece 7. And an input unit 13 for inputting various types of information. Further, the processing head 2 includes a processing lens 5 provided inside, and a processing nozzle 6 attached to the tip of the processing head 2.

  In the laser processing apparatus according to the present embodiment configured as described above, the laser beam 3 output from the laser oscillation unit 1 is guided to the processing head 2 by the optical unit 4 including a mirror and a lens. The laser beam 3 guided to the processing head 2 passes through the processing lens 5 in the processing head 2, is guided to the processing nozzle 6 attached to the tip of the processing head 2, and from the processing nozzle 6 to the processing table 12. The workpiece 7 is irradiated. At this time, the laser beam 3 is focused on the processing object 7 by the processing lens 5. Further, the machining head 2 and the machining table 12 are relatively moved by a drive mechanism (not shown) to perform machining of a desired shape.

  On the other hand, the assist gas 10 supplied from the assist gas supply unit 8 and passed through the assist gas adjustment unit 9 is guided into the machining head 2. Then, the assist gas guided to the inside of the processing head 2 is irradiated to the processing object 7 together with the laser beam 3 from the processing nozzle 6. These operations are controlled by the control unit 11.

  The assist gas supply unit 8 is a means for supplying the gas itself to be used. A gas cylinder such as oxygen or nitrogen, a combination of liquid oxygen and a vaporizer, a compressor for compressing and supplying air, and separating only nitrogen from the air For example, a nitrogen separation device to be supplied is used. In the present embodiment, a gas cylinder storing various assist gases is used as the assist gas supply unit 8.

  The assist gas adjustment unit 9 switches the type of the assist gas 10 supplied from the assist gas supply unit 8 and supplied to the processing head 2 according to the material and plate thickness of the workpiece 7 and adjusts the pressure. The laser beam 3 and the assist gas 10 appropriately selected and adjusted by the assist gas adjusting unit 9 are irradiated onto the processing object 7 together, so that a laser for cutting or drilling the processing object 7 for the first time. It can be carried out with good accuracy in good processing.

  FIG. 2 is a schematic configuration diagram mainly illustrating the configuration of the assist gas adjusting unit 9 in order to describe the assist gas supply method in the laser processing apparatus according to the present embodiment. The assist gas supply unit 8 includes an oxygen gas source 15A that is a storage and supply source of oxygen gas, a nitrogen gas source 15B that is a storage and supply source of nitrogen gas, an argon gas source 15C that is a storage and supply source of argon gas, In addition, a mixed gas in which nitrogen and oxygen are mixed in advance at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”, that is, the oxygen concentration of the mixed gas is “ A mixed gas source 15D that is a storage and supply source of a mixed gas of nitrogen and oxygen that is set to “0.1 volume% to 0.5 volume%” is provided. In the present embodiment, gas cylinders are provided as an example of these gas sources.

  The assist gas is sent from the gas sources 15A to 15D and sent to the assist gas adjusting unit 9 via the pipes 16A to 16D (hereinafter, the pipes 16A to 16D may be collectively referred to as the pipe 16). The pipes 16A to 16D are connected to gas type selection solenoid valves 17A to 17D, respectively. One end of each of the pipes 19A to 19D is connected to each of the gas type selection solenoid valves 17A to 17D, and the other ends of the pipes 19A to 19D are combined into one and connected to one end of the pipe 20. Yes.

  In addition, check valves 18A to 18D that allow gas to flow only in one direction are provided in the middle of the pipes 19A to 19D, respectively. The operation of the check valve 18 is as follows. The gas type selection solenoid valve 17 is directional in resistance to gas pressure, and is resistant to pressure from the pipe 16 side, but is weak to pressure from the pipe 19 side. For this reason, when the pressure on the pipe 19 side becomes high, the assist gas may flow backward from the pipe 19 to the pipe 16.

  Therefore, for example, when the gas type selection solenoid valve 17D is opened and the other gas type selection solenoid valves 17A to 17C are closed, a mixed gas of nitrogen and oxygen flows through the pipe 19D. At this time, if the pressure in the pipe 19D is higher than the pressure in the pipe 19A, a mixed gas of nitrogen and oxygen may flow into the pipe 16A from the pipe 19A. Therefore, in order to prevent this, a check valve 18 is provided so that no pressure is applied to the pipe 19 side of the gas type selection electromagnetic valve 17.

  A proportional control valve 21 is connected to the other end of the pipe 20, the other end of the proportional control valve 21 is connected to the pipe 22, and the machining head 2 is connected to the other end of the pipe 22 as a discharge unit. ing. Further, a nozzle 6 is provided at the tip of the processing head 2 as an injection port. The processing head 2 is provided with a pressure sensor 23.

  The assist gas is switched by the gas type control unit 25 of the control unit 11 by opening one of the gas type selection electromagnetic valves 17A to 17D and closing the other electromagnetic valve. Further, the pressure of the assist gas is adjusted by feedback control of the opening degree of the proportional control valve 21 based on the pressure value of the pressure sensor 23 by the pressure control unit 26 of the control unit 11.

  In the laser processing apparatus according to the present embodiment configured as described above, in the laser processing of aluminum that is a feature of the present invention, “nitrogen: oxygen = 99.5: 0.5 to 99.9 is used as an assist gas. : 0.1 (volume%) ”is used, and a mixed gas of nitrogen and oxygen mixed at a ratio of“ 0.1 (volume%) ”is used. Thereby, in the laser processing of aluminum, dross does not adhere to the processed object 7 after processing, and the cloudiness of the cut surface due to oxidation does not occur.

  Therefore, the laser processing apparatus according to the present embodiment does not require post-processes such as a dross removal process and an antioxidant treatment process, which are indispensable for laser processing of aluminum by the conventional laser processing apparatus. In addition, a laser processing apparatus capable of laser processing of aluminum with excellent quality has been realized.

  Moreover, in the laser processing apparatus concerning this Embodiment mentioned above, said mixed gas is used as assist gas. Thereby, the cut surface after laser processing of aluminum is not a cloudy surface but a glossy surface, and the influence of oxidation of the cut surface can be prevented.

  In the laser processing apparatus according to the above-described embodiment, nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. As a mixed gas storage / supply source, a gas cylinder filled with the above-mentioned mixed gas in advance is used. Thereby, the laser processing apparatus using the mixed gas described above as an assist gas can be realized with a very simple configuration.

  Next, an operation when performing laser processing with the laser processing apparatus according to the present embodiment described above will be described. Here, a case where laser processing of aluminum, which is a feature of the present invention, is described.

  First, the object 7 to be processed is fixed on the processing table 12 and set at a predetermined position by a driving mechanism (not shown). Next, a predetermined processing instruction is input using the input unit 13. The processing instruction may be directly input using the input unit 13 or may be configured to select a predetermined processing program incorporated in advance in the storage means in the control unit 11, for example.

  When a processing instruction is input or selected, processing is started according to the processing instruction, and the laser oscillation unit 1 outputs the laser beam 3 under the control of the control unit 11. The laser beam 3 output from the laser oscillation unit 1 is guided to the machining head 2 by the optical unit 4. The laser beam 3 guided to the processing head 2 passes through the processing lens 5 in the processing head 2, is condensed, and is guided to the processing nozzle 6 attached to the tip of the processing head 2. 6 to the processing object 7 on the processing table 12.

  Further, the supply of the assist gas is started together with the output of the laser beam 3, and a mixed gas of nitrogen and oxygen is sent from the mixed gas source 15D of the assist gas supply unit 8 as the assist gas. The assist gas sent from the mixed gas source 15D is sent into the assist gas adjusting unit 9 through the pipe 16D. Here, in the laser processing apparatus according to the present embodiment, when performing laser processing of aluminum, “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume) as an assist gas. %) ”And a mixed gas of nitrogen and oxygen mixed at a ratio of“

  Therefore, the control unit 11 opens the gas type selection electromagnetic valve 17D based on the processing instruction, and closes the other gas type selection electromagnetic valves 17A to 17C. Thereby, the assist gas sent to the inside of the assist gas adjusting unit 9 through the pipe 16D passes through the gas type electromagnetic valve 17D, and is sent to the proportional control valve 21 through the check valve 18, the pipe 19D, and the pipe 20. . At this time, the assist gas in the pipe 19D does not flow into the pipes 16A to 16C due to the function of the check valves 18A to 18C.

  The assist gas sent to the proportional control valve 21 is adjusted in pressure by the opening degree of the proportional control valve 21 and sent to the machining head 2 through the pipe 22. Here, in the machining head 2, the pressure of the assist gas is measured by the pressure sensor 23, and the pressure data is transmitted to the pressure control unit 26 of the control unit 11. The pressure control unit 26 feedback-adjusts the opening degree of the proportional control valve 21 based on the pressure data measured by the pressure sensor 23 so that the assist gas has a desired pressure.

  The assist gas adjusted to a desired pressure and sent to the machining head 2 is irradiated onto the workpiece 7 together with the laser beam 3 from the machining nozzle 6. As described above, a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” is supplied from the processing nozzle 6 at a desired pressure. Irradiated as an assist gas toward the workpiece 7.

  Then, in a state where the assist gas and the laser beam 3 are irradiated onto the processing object 7, the processing head 2 and the processing table 12 are relatively moved by a drive mechanism (not shown) to move the processing object 7. On the other hand, a desired shape is processed. The series of operations described above is controlled by the control unit 11.

  In the laser processing method using the laser processing apparatus configured as described above, the assist gas is mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. Since the mixed gas of nitrogen and oxygen is used, processing can be performed without causing dross to adhere to the processed object 7 after processing in laser processing of aluminum and without causing cloudiness of the cut surface.

  Therefore, in the laser processing method using the laser processing apparatus according to the present embodiment, post-processes such as a dross removing process and an anti-oxidation process which are essential in the laser processing of aluminum by the conventional laser processing method are unnecessary. Yes, laser processing of aluminum with excellent productivity and quality is possible.

  Further, in the laser processing method according to the present embodiment described above, since the above mixed gas is used as the assist gas, it is possible to obtain a glossy cut surface as a cut surface of the aluminum after the laser processing instead of a white turbid surface. In addition, it is possible to perform processing that prevents the influence of oxidation on the cut surface.

  In the laser processing method according to the present embodiment described above, nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. As a mixed gas storage / supply source, a gas cylinder filled with the above-mentioned mixed gas in advance is used. Thereby, laser processing using the above-mentioned mixed gas as an assist gas can be realized very easily.

  FIGS. 3A to 3C are views showing the nitrogen and the nitrogen purity changed in laser cutting of aluminum by the conventional laser processing apparatus (processing method) and the laser processing apparatus (processing method) according to the present embodiment. It is the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing a cutting process using the mixed gas with oxygen as an assist gas. 3-1 and FIGS. 3-5 to 3-8 show the conventional laser processing apparatus (processing method), and FIGS. 3-2 to 3-4 show the laser processing apparatus (processing) according to the present embodiment. Method).

  3-1 and 3-5 to 3-8, dross adheres to the aluminum after processing in the processing method using liquid nitrogen (nitrogen ratio of 99.9% or more) as an assist gas, which is a conventional processing method. (FIG. 3-1), and a case where a mixed gas having a nitrogen ratio of 99.3% or less, that is, an oxygen concentration of 0.7% or more is used as an assist gas (FIGS. 3-5 to 3) Even in -8), it can be seen that dross is attached to the processed aluminum. That is, dross adheres under the condition of the assist gas disclosed in Patent Document 1, in which the ratio of oxygen to nitrogen is “greater than 0% by volume and less than 8% by volume, preferably 150 ppm to 5% by volume”. In most cases, the effect of preventing the adhesion of dross cannot be obtained.

  On the other hand, from FIG. 3-2 to FIG. 3-4, laser cutting of aluminum by the laser processing apparatus (processing method) according to the present embodiment, that is, nitrogen purity 99.9% by volume (oxygen concentration 0.1% by volume) When a mixed gas having a nitrogen purity of 99.7% by volume (oxygen concentration of 0.3% by volume) and a nitrogen purity of 99.5 (oxygen concentration of 0.5% by volume) is used as an assist gas, It can be seen that dross is not attached. Thereby, it can be said that the effect of this invention that the adhesion | attachment of the dross to the aluminum after a process can be prevented is acquired.

  In addition, in order to clarify the difference in the state of dross adhesion to aluminum after cutting, after cutting the aluminum plate having a mixing ratio of nitrogen and oxygen in the mixed gas used for the assist gas and a thickness of 6 mm FIG. 4 shows the relationship between the maximum height of the dross attached to the aluminum. As apparent from FIG. 4, dross does not adhere to the cut aluminum only when the oxygen concentration in the assist gas is 0.1 vol% to 0.5 vol%. Moreover, as a result of observing the sample after processing shown in FIGS. 3-2 to 3-4, when an assist gas having an oxygen concentration of 0.1 volume% to 0.5 volume% was used, it became cloudy. It was confirmed that a glossy cut surface was obtained instead of a cut surface, and that the influence of oxidation could be prevented.

Embodiment 2. FIG.
In the first embodiment described above, the storage and storage of a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. Although the case where the gas cylinder in which the above-described mixed gas is sealed in advance is used as the supply source has been described, in the present embodiment, the existing oxygen gas source and the nitrogen gas source are used, and the function of the assist gas adjusting unit 9 allows the “nitrogen” : Oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%) ”will be described as a case where a mixed gas of nitrogen and oxygen mixed at a ratio of“ oxygen ”is supplied as an assist gas.

  FIG. 5 is a diagram corresponding to FIG. 2, and is a schematic configuration diagram mainly showing the configuration of the assist gas adjustment unit 9 in order to explain the assist gas supply method in the laser processing apparatus according to the present embodiment. . The same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG.

  The assist gas supply unit 8 in the laser processing apparatus according to the present embodiment is different from the assist gas supply unit 8 in the first embodiment in that it does not have the nitrogen-oxygen mixed gas source 15D. In the case of this embodiment, for example, the compressed air source 15E is connected to the pipe 16D. The compressed air source 15E is, for example, a compressor.

  Further, the assist gas adjusting unit 9 in the laser processing apparatus according to the present embodiment is different from the assist gas adjusting unit 9 in the first embodiment in that an electropneumatic valve 30 is added in the middle of the pipe 19A, This is that the pipe 19B is connected and the oxygen concentration sensor 31 is added to the connection destination of the pipe 19A and the pipe 19B. That is, as shown in FIG. 5, the oxygen gas pipe 19 </ b> A merges with the nitrogen gas pipe 19 </ b> B via the electropneumatic valve 30 and is connected to the oxygen concentration sensor 31. The configuration of the piping and the like after the oxygen concentration sensor 31 is the same as that in the first embodiment (FIG. 4).

  As an assist gas for laser processing of aluminum, a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” is used. The use is also the same as in the first embodiment.

  And the control part 11 in the laser processing apparatus concerning this Embodiment differs from the control part 11 in Embodiment 1 in that the oxygen-nitrogen mixing ratio control part 32 is added. The oxygen / nitrogen mixing ratio control unit 32 controls the electropneumatic valve 30 and the oxygen concentration sensor 31 to adjust the mixing ratio of nitrogen and oxygen.

  Next, an operation when performing laser processing with the laser processing apparatus according to the present embodiment described above will be described. Here, a case where laser processing of aluminum, which is a feature of the present invention, is described.

  First, the object 7 to be processed is fixed on the processing table 12 and set at a predetermined position by a driving mechanism (not shown). Next, a predetermined processing instruction is input using the input unit 13. The processing instruction may be directly input using the input unit 13 or may be configured to select a predetermined processing program incorporated in advance in the storage means in the control unit 11, for example.

  When a processing instruction is input or selected, processing is started according to the processing instruction, and the laser oscillation unit 1 outputs the laser beam 3 under the control of the control unit 11. The laser beam 3 output from the laser oscillation unit 1 is guided to the machining head 2 by the optical unit 4. The laser beam 3 guided to the processing head 2 passes through the processing lens 5 in the processing head 2, is condensed, and is guided to the processing nozzle 6 attached to the tip of the processing head 2. 6 to the processing object 7 on the processing table 12.

  In addition, the supply of the assist gas is started together with the output of the laser beam 3. In order to supply the assist gas, first, the gas type selection electromagnetic valves 17A and 17B are opened by the gas type control unit 25 of the control unit 11, and the gas type selection electromagnetic valves 17C and 17D are closed. Thus, oxygen gas and nitrogen gas are mixed at the junction of the pipe 19 </ b> A and the pipe 19 </ b> B and reach the oxygen concentration sensor 31. Then, the oxygen concentration of the mixed gas in which oxygen gas and nitrogen gas are mixed is measured by the oxygen concentration sensor 31, and the measurement data is sent to the oxygen / nitrogen mixture ratio control unit 32.

  When the measurement data is received, the oxygen-nitrogen mixture ratio control unit 32 is configured so that the oxygen concentration of the mixed gas becomes “0.1 vol% to 0.5 vol%”, that is, nitrogen and oxygen are “nitrogen: Feedback control is performed on the electropneumatic valve 30 so as to adjust the flow rate of the oxygen gas so that the oxygen is mixed at a ratio of “oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. Do. A mixed gas of oxygen gas and nitrogen gas having a desired oxygen concentration, that is, assist gas is sent to the proportional control valve 21 through the pipe 20.

  The assist gas sent to the proportional control valve 21 is adjusted in pressure by the opening degree of the proportional control valve 21 and sent to the machining head 2 through the pipe 22. Here, in the machining head 2, the pressure of the assist gas is measured by the pressure sensor 23, and the pressure data is transmitted to the pressure control unit 26 of the control unit 11. The pressure control unit 26 feedback-adjusts the opening degree of the proportional control valve 21 based on the pressure data measured by the pressure sensor 23 so that the assist gas has a desired pressure.

  The assist gas adjusted to a desired pressure and sent to the machining head 2 is irradiated onto the workpiece 7 together with the laser beam 3 from the machining nozzle 6. As described above, a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” is supplied from the processing nozzle 6 at a desired pressure. Irradiated as an assist gas toward the workpiece 7.

  Then, in a state where the assist gas and the laser beam 3 are irradiated onto the processing object 7, the processing head 2 and the processing table 12 are relatively moved by a drive mechanism (not shown) to move the processing object 7. On the other hand, a desired shape is processed. The series of operations described above is controlled by the control unit 11.

  When only oxygen gas or nitrogen gas is used as the assist gas, the necessary gas type selection electromagnetic valve 17 is appropriately opened and closed, the operation of the oxygen / nitrogen mixing ratio control unit 32 is stopped, and the electropneumatic valve 30 is opened. Just keep it in a state. Further, although the electropneumatic valve 30 is provided in the oxygen gas pipe 19A, an electropneumatic valve may be provided in the nitrogen gas pipe 19B.

  In the laser processing apparatus according to the present embodiment configured as described above, they are mixed in advance at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. Instead of using a gas cylinder of mixed gas of nitrogen and oxygen, a commonly used nitrogen cylinder and oxygen cylinder are used. Also in this case, similarly to the case of the first embodiment, laser processing of aluminum without adhesion of dross can be performed, and the same effect of the present invention as in the case of the first embodiment can be obtained. In this case, the running cost can be reduced because a gas cylinder of a mixed gas of nitrogen and oxygen previously mixed at the above ratio is not used.

Embodiment 3 FIG.
In the second embodiment, a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” is used as an electropneumatic valve. In the present embodiment, the function of the assist gas adjustment unit 9 is used without using a control mechanism, and “nitrogen: oxygen = 99.5: 0. The case where a mixed gas of nitrogen and oxygen mixed at a ratio of “5-99.9: 0.1 (volume%)” is supplied as an assist gas will be described.

  FIG. 6 is a diagram corresponding to FIG. 2, and is a schematic configuration diagram mainly showing the configuration of the assist gas adjusting unit 9 in order to explain the assist gas supply method in the laser processing apparatus according to the present embodiment. . The same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG.

  The assist gas supply unit 8 in the laser processing apparatus according to the present embodiment is different from the assist gas supply unit 8 in the first embodiment in that it does not have the nitrogen-oxygen mixed gas source 15D. In the case of this embodiment, for example, the compressed air source 15E is connected to the pipe 16D. The compressed air source 15E is, for example, a compressor.

  Further, the assist gas adjusting unit 9 in the laser processing apparatus according to the present embodiment is different from the assist gas adjusting unit 9 in the first embodiment in that it branches from the oxygen gas pipe 16A and passes through the regulator 39A and the orifice 38A. From the piping 40A leading to the gas type selection solenoid valve 35 and the piping 40B branching from the nitrogen gas piping 16B to the gas type selection solenoid valve 35 via the regulator 39B and the orifice 38B, and from the gas type selection solenoid valve 35 A point is that a pipe 37 connected to the pipe 20 via the check valve 36 is provided. In addition, the structure of piping etc. after the piping 20 is the same as that of the case of Embodiment 1 (FIG. 4).

  Here, the hole diameter of the orifice 38A through which oxygen gas passes and the orifice 38B through which nitrogen gas passes is such that the mixing ratio of nitrogen and oxygen is nitrogen: oxygen = 99.5: 0.5 to 99 under a predetermined gas pressure. .9: 0.1 (volume%), and the regulators 39A and 39B are adjusted so that a predetermined gas pressure is applied to the orifices 38A and 38B.

  Next, an operation when performing laser processing with the laser processing apparatus according to the present embodiment described above will be described. Here, a case where laser processing of aluminum, which is a feature of the present invention, is described.

  First, the object 7 to be processed is fixed on the processing table 12 and set at a predetermined position by a driving mechanism (not shown). Next, a predetermined processing instruction is input using the input unit 13. The processing instruction may be directly input using the input unit 13 or may be configured to select a predetermined processing program incorporated in advance in the storage means in the control unit 11, for example.

  When a processing instruction is input or selected, processing is started according to the processing instruction, and the laser oscillation unit 1 outputs the laser beam 3 under the control of the control unit 11. The laser beam 3 output from the laser oscillation unit 1 is guided to the machining head 2 by the optical unit 4. The laser beam 3 guided to the processing head 2 passes through the processing lens 5 in the processing head 2, is condensed, and is guided to the processing nozzle 6 attached to the tip of the processing head 2. 6 to the processing object 7 on the processing table 12.

  In addition, the supply of the assist gas is started together with the output of the laser beam 3. In order to supply the assist gas, first, the gas type selection electromagnetic valve 35 is opened by the gas type control unit 25 of the control unit 11, and the gas type selection electromagnetic valves 17A to 17D are closed. As a result, the oxygen gas and the nitrogen gas are mixed at the joining portion of the pipe 40A and the pipe 40B, passed through the gas type selection electromagnetic valve 35, and led to the pipe 37.

  Here, the oxygen gas is adjusted to a predetermined pressure by the regulator 39A in the pipe 40A and passes through the orifice 38A. On the other hand, the nitrogen gas is adjusted to a predetermined pressure by the regulator 39B in the pipe 40B and passes through the orifice 38B. Thereby, oxygen gas and nitrogen gas are in a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” based on the setting of the hole diameters of the orifices 38A and 38B. The mixed gas is passed through the gas type selection solenoid valve 35 and the check valve 36 as a mixed gas (assist gas) and led to the pipe 37.

  The assist gas led to the pipe 37 is sent to the proportional control valve 21 via the pipe 20, and the pressure of the assist gas sent to the proportional control valve 21 is adjusted by the opening degree of the proportional control valve 21. To the machining head 2. Here, in the machining head 2, the pressure of the assist gas is measured by the pressure sensor 23, and the pressure data is transmitted to the pressure control unit 26 of the control unit 11. The pressure control unit 26 feedback-adjusts the opening degree of the proportional control valve 21 based on the pressure data measured by the pressure sensor 23 so that the assist gas has a desired pressure.

  The assist gas adjusted to a desired pressure and sent to the machining head 2 is irradiated onto the workpiece 7 together with the laser beam 3 from the machining nozzle 6. As described above, a mixed gas of nitrogen and oxygen mixed at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)” is supplied from the processing nozzle 6 at a desired pressure. Irradiated as an assist gas toward the workpiece 7.

  Then, in a state where the assist gas and the laser beam 3 are irradiated onto the processing object 7, the processing head 2 and the processing table 12 are relatively moved by a drive mechanism (not shown) to move the processing object 7. On the other hand, a desired shape is processed. The series of operations described above is controlled by the control unit 11.

  When only oxygen gas or nitrogen gas is used as the assist gas, the gas type selection electromagnetic valve 35 may be closed and the necessary gas type selection electromagnetic valve 17 may be opened and closed as appropriate.

  In the laser processing apparatus according to the present embodiment configured as described above, they are mixed in advance at a ratio of “nitrogen: oxygen = 99.5: 0.5 to 99.9: 0.1 (volume%)”. Instead of using a gas cylinder of mixed gas of nitrogen and oxygen, a commonly used nitrogen cylinder and oxygen cylinder are used. Also in this case, similarly to the case of the first embodiment, laser processing of aluminum without adhesion of dross can be performed, and the same effect of the present invention as in the case of the first embodiment can be obtained.

  In this case, since the gas cylinder of the mixed gas of nitrogen and oxygen mixed in advance at the above ratio is not used, the running cost can be reduced as in the case of the second embodiment. Further, when compared with the laser processing apparatus according to the second embodiment, the mixing ratio of oxygen gas and nitrogen gas is fixed, but a special control unit for controlling the mixing ratio is not required, so the apparatus configuration is simplified. The initial cost can be reduced.

  As described above, the laser processing apparatus according to the present invention is useful for efficient laser processing, and is particularly suitable for laser processing of aluminum.

It is a schematic block diagram which shows typically the whole structure of the laser processing apparatus concerning Embodiment 1 of this invention. FIG. 3 is a schematic configuration diagram mainly illustrating a configuration of an assist gas adjusting unit in order to explain an assist gas supply method in the laser processing apparatus according to the first embodiment; It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the conventional laser processing apparatus (processing method). It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the laser processing apparatus (processing method) concerning Embodiment 1. FIG. It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the laser processing apparatus (processing method) concerning Embodiment 1. FIG. It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the laser processing apparatus (processing method) concerning Embodiment 1. FIG. It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the conventional laser processing apparatus (processing method). It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the conventional laser processing apparatus (processing method). It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the conventional laser processing apparatus (processing method). It is the figure which showed the photograph of the cut surface which showed the adhesion state of the dross with respect to the aluminum after a process at the time of performing the cutting process of aluminum with the conventional laser processing apparatus (processing method). It is a characteristic view showing the relationship between the mixing ratio of nitrogen and oxygen in the mixed gas used for the assist gas and the maximum height of dross attached to aluminum after the aluminum plate is cut. FIG. 10 is a schematic configuration diagram mainly illustrating a configuration of an assist gas adjusting unit in order to explain an assist gas supply method in the laser processing apparatus according to the second embodiment; FIG. 9 is a schematic configuration diagram mainly illustrating a configuration of an assist gas adjusting unit in order to explain an assist gas supply method in a laser processing apparatus according to a third embodiment;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillation part 2 Processing head 3 Laser beam 4 Optical part 5 Processing lens 6 Processing nozzle 7 Processing object 8 Assist gas supply part 9 Assist gas adjustment part 10 Assist gas 11 Control part 12 Processing table 13 Input part 15A Oxygen gas source 15B Nitrogen gas source 15C Argon gas source 15D Nitrogen oxygen mixed gas source 15E Compressed air source 16A, 16B, 16C, 16D Piping 17A, 17B, 17C, 17D Gas type selection solenoid valve 18A, 18B, 18C, 18D Check valve 19A, 19B, 19C, 19D Piping 20 Piping 21 Proportional control valve 22 Piping 23 Pressure sensor 25 Gas type control unit 26 Pressure control unit 30 Electropneumatic valve 31 Oxygen concentration sensor 32 Oxygen / nitrogen mixing ratio control unit 35 Gas type selection solenoid valve 36 Check valve 37 Piping 38A, 38B Orifice 39A, 39B Regulator 40A, 40B Piping

Claims (7)

A laser processing apparatus that performs cutting of the aluminum workpiece by irradiating the aluminum workpiece with a laser beam and supplying an assist gas to the aluminum workpiece,
Laser beam output means for outputting the laser beam;
Irradiation means for directing and irradiating the laser beam to the aluminum workpiece;
Assist gas supply means for supplying a mixed gas of nitrogen gas and oxygen gas having a mixing ratio of oxygen gas of 0.1 volume% to 0.5 volume% as the assist gas to the aluminum workpiece;
Control means for controlling cutting processing in the own device;
A laser processing apparatus comprising: The assist gas supply means includes a mixed gas storage / supply means for storing a mixed gas of nitrogen gas and oxygen gas mixed in advance at a mixing ratio of oxygen gas of 0.1 volume% to 0.5 volume%. The laser processing apparatus according to claim 1. The laser processing apparatus according to claim 2, wherein the storage / supply unit is a gas cylinder. As the assist gas supply means,
Nitrogen gas storage and supply means for storing and supplying nitrogen gas;
Oxygen gas storage and supply means for storing and supplying oxygen gas;
The mixing ratio of the oxygen gas between the nitrogen gas supplied from the nitrogen gas storage / supply means and the oxygen gas supplied from the oxygen gas storage / supply means is 0.1 volume% to 0.5 volume%. Mixing means for mixing with,
The laser processing apparatus according to claim 1, comprising: Oxygen concentration measuring means for measuring the oxygen concentration of the mixed gas mixed by the mixing means,
Adjusting the mixing means so that the mixing ratio of oxygen gas in the mixed gas is 0.1 volume% to 0.5 volume% based on the measurement result in the oxygen concentration measuring means;
The laser processing apparatus according to claim 4. Nitrogen gas regulation means for regulating the amount of nitrogen gas supplied from the nitrogen gas storage / supply means;
Oxygen gas regulating means for regulating the amount of oxygen gas supplied from the oxygen gas storage / supply means;
With
The mixing means is configured such that the nitrogen gas supplied by being regulated by the nitrogen gas regulating means and the oxygen gas regulated and supplied by the oxygen gas regulating means are mixed at a volume ratio of 0.1 volume of oxygen gas. % To 0.5% by volume,
The laser processing apparatus according to claim 4. A laser processing method for cutting the aluminum workpiece by irradiating the aluminum workpiece with a laser beam and supplying an assist gas to the aluminum workpiece,
Using a mixed gas of nitrogen gas and oxygen gas having a mixing ratio of oxygen gas of 0.1 volume% to 0.5 volume% as an assist gas;
A laser processing method characterized by the above.