JP7257372B2 - laser processing machine - Google Patents

Description

The present invention relates to a laser processing machine .

2. Description of the Related Art A laser processing machine that cuts a sheet metal (an example of a material) with a laser beam emitted from a laser oscillator to manufacture a product of a predetermined shape is widely used. 2. Description of the Related Art In a laser processing machine, it is necessary to appropriately control a laser beam irradiated onto a sheet metal according to processing conditions (see Patent Document 1, for example). The processing conditions include multiple conditions such as the cutting speed when cutting sheet metal with laser light, the laser output of the laser oscillator, the focal length of the focusing lens provided in the laser processing head, and the opening diameter of the laser irradiation nozzle. there is Individual conditions included in the processing conditions must be set to appropriate values according to the material and thickness of the sheet metal. Since the optimum conditions differ depending on the material and plate thickness of the work, the processing conditions are set for each combination of sheet metal material and plate thickness.

JP 2004-009085 A

In setting processing conditions, it is necessary to determine various conditions for a large number of materials and plate thicknesses and verify whether these conditions are appropriate. Therefore, setting the machining conditions requires a huge number of man-hours. Therefore, there is a demand for a technique capable of setting machining conditions with a smaller number of man-hours.

One aspect of the present invention is to provide a laser processing machine that can set processing conditions with a small number of man-hours.

One aspect of the present invention includes a laser processing unit that cuts a material using a laser beam emitted from a laser oscillator, and a control device that controls the laser processing unit according to processing conditions including a cutting speed. The unit includes a kerf width detector that detects the actual kerf width processed by the laser processing unit, and the controller uses a cutting speed theoretical formula for calculating a theoretical value of the cutting speed according to the material and plate thickness of the material. Based on the theoretical value calculation unit for calculating the theoretical value of the cutting speed, the parameter adjustment unit for adjusting the parameters constituting the theoretical cutting speed formula, and the cutting corrected by the parameter adjustment unit and a processing condition setting unit for setting processing conditions including the cutting speed calculated based on the speed theoretical formula, the cutting speed theoretical formula being a parameter that can be adjusted by the parameter adjusting unit, the average absorption of laser light to the material. The theoretical value calculation unit compares the average kerf width specified in the calculation of the cutting speed theoretical formula with the actual kerf width detected by the kerf width detection unit, A laser processing machine that learns a correction absorption rate based on the deviation between the average kerf width and the actual kerf width.

According to one aspect of the present invention, machining conditions can be set with a small number of man-hours.

FIG. 1 is a configuration diagram schematically showing a laser processing machine according to the first embodiment. FIG. 2 is a block diagram showing the configuration of a laser processing machine centering on an NC device. FIG. 3 is an explanatory view showing a cutting state of sheet metal by a laser beam. FIG. 4 is a flowchart for explaining the procedure for setting processing conditions. FIG. 5 is an explanatory diagram illustrating parameters related to laser light. FIG. 6 is an explanatory diagram for explaining the incident angle. FIG. 7 is a graph showing the relationship between plate thickness and average absorptance. FIG. 8 is an explanatory diagram for explaining the average kerf width. FIG. 9 is a graph showing the relationship between plate thickness and cutting speed. FIG. 10 is a graph showing the relationship between average absorptance and plate thickness. FIG. 11 is a graph showing the relationship between plate thickness and cutting speed when the average absorbance is corrected. FIG. 12 is an explanation showing an example of processing conditions. FIG. 13 is a graph showing the relationship between plate thickness and cutting speed when the material is stainless steel and the laser output is 6 kW. FIG. 14 is a graph showing the relationship between plate thickness and cutting speed when the average absorbance is corrected. FIG. 15 is a graph showing the relationship between plate thickness and cutting speed when the material is stainless steel and the laser output is 9 kW. FIG. 16 is a graph showing the relationship between plate thickness and cutting speed when the average absorbance is corrected. FIG. 17 is a graph showing the relationship between plate thickness and cutting speed when the material is aluminum and the laser output is 6 kW. FIG. 18 is a graph showing the relationship between plate thickness and cutting speed when the average absorptance is corrected. FIG. 19 is a graph showing the relationship between plate thickness and cutting speed when the material is aluminum and the laser output is 9 kW. FIG. 20 is a graph showing the relationship between plate thickness and cutting speed when the average absorbance is corrected. FIG. 21 is a block diagram showing the configuration of a laser processing machine according to the second embodiment.

(First embodiment)
A laser processing machine and a processing condition setting method according to the present embodiment will be described below. A laser processing machine 100 shown in FIG. 1 is a processing machine that cuts a material with a laser beam. The material to be processed is sheet metal W, for example. A laser processing machine 100 includes a laser oscillator 10 , a process fiber 12 and a laser processing unit 20 . The laser processing machine 100 also includes an assist gas supply device 40 , an operation display section 50 and an NC device 60 .

A laser oscillator 10 generates and emits laser light. As the laser oscillator 10, a laser oscillator that amplifies excitation light emitted from a laser diode and emits laser light of a predetermined wavelength, or a laser oscillator that directly uses the laser light emitted from the laser diode is suitable. The laser oscillator 10 is, for example, a solid-state laser oscillator, a fiber laser oscillator, a disk laser oscillator, or a direct diode laser oscillator (DDL oscillator).

A laser oscillator 10 emits laser light in the 1 μm band with a wavelength of 900 nm to 1100 nm. Taking a fiber laser oscillator and a DDL oscillator as examples, the fiber laser oscillator emits laser light with a wavelength of 1060 nm to 1080 nm, and the DDL oscillator emits laser light with a wavelength of 910 nm to 950 nm.

The process fiber 12 transmits laser light emitted from the laser oscillator 10 to the laser processing unit 20 .

The laser processing unit 20 cuts the sheet metal W using laser light transmitted by the process fiber 12 . The laser processing unit 20 has a processing table 21 on which the sheet metal W is placed, a gate-shaped X-axis carriage 22 , a Y-axis carriage 23 , and a collimator unit 30 . The X-axis carriage 22 is configured to be movable along the X-axis direction on the processing table 21 . The Y-axis carriage 23 is configured to be movable on the X-axis carriage 22 along the Y-axis direction perpendicular to the X-axis.

The collimator unit 30 irradiates the sheet metal W with the laser light transmitted by the process fiber 12 . The collimator unit 30 includes a collimator lens 31 into which the laser beam emitted from the exit end of the process fiber 12 is incident, and a laser beam emitted from the collimator lens 31 that is reflected downward in the Z-axis direction perpendicular to the X-axis and the Y-axis. It has a bend mirror 33 that allows The collimator unit 30 also has a focusing lens 34 that focuses the laser beam reflected by the bend mirror 33 . The collimator lens 31, the bend mirror 33, and the condenser lens 34 are arranged with their optical axes adjusted in advance.

The collimator unit 30 has a processing head 35 . A nozzle 36 for emitting laser light is detachably attached to the tip of the processing head 35 . A circular opening is provided at the tip of the nozzle 36 , and the laser beam converged by the converging lens 34 is irradiated onto the sheet metal W from the opening at the tip of the nozzle 36 .

The collimator unit 30 is fixed to the Y-axis carriage 23 that is movable in the Y-axis direction, and the Y-axis carriage 23 is provided on the X-axis carriage 22 that is movable in the X-axis direction. Therefore, the processing head 35, that is, the position where the sheet metal W is irradiated with the laser beam can be moved in the plane of the sheet metal W (in the X-axis direction and the Y-axis direction). Instead of moving the processing head 35 along the surface of the sheet metal W, the laser processing machine 100 may be configured to move the sheet metal W while the position of the processing head 35 is fixed. The laser processing machine 100 only needs to have a configuration in which the processing head 35 is moved relative to the surface of the sheet metal W. FIG.

The laser processing machine 100 configured as described above cuts the sheet metal W with a laser beam emitted from the laser oscillator 10 to manufacture a product having a predetermined shape.

The assist gas supply device 40 supplies nitrogen, oxygen, a mixed gas of nitrogen and oxygen, or air as an assist gas to the processing head 35 . During processing of the sheet metal W, the assist gas is blown onto the sheet metal W through the opening of the nozzle 36 . The assist gas discharges the molten metal within the kerf width where the sheet metal W is melted.

The operation display unit 50 is integrally composed of an operation unit operated by a user to input information to the NC unit 60 and a display unit for displaying information output from the NC unit 60 . By operating the operation display unit 50 , the user can input various information other than the material and thickness of the sheet metal W to the NC device 60 . Also, the user can grasp the processing conditions and the like from the information displayed on the operation display unit 50 .

The operation display section 50 may be configured so that the operation section and the display section are separate bodies. Further, the operation unit may be configured to input predetermined data generated by a separately installed computer (not shown) to the NC device 60 through communication.

The NC device 60 is a control device that controls each part of the laser processing machine 100 . As shown in FIG. 2, the NC device 60 has a machining control section 70, a machining condition holding section 80, a machining program holding section 85, and a machining condition processing unit 90 as functional configurations. .

The machining control unit 70 reads the machining program from the machining program holding unit 85 and reads the machining conditions corresponding to the material and thickness of the sheet metal W to be machined from the machining condition holding unit 80 . The processing control section 70 controls the laser oscillator 10 and the laser processing unit 20 based on the processing program and processing conditions. By the processing control unit 70 controlling the laser oscillator 10 and the laser processing unit 20, the sheet metal W is processed according to the processing conditions.

The processing condition holding unit 80 holds processing conditions for cutting the sheet metal W. As shown in FIG. The processing conditions include a cutting speed when cutting the sheet metal W with a laser beam. In addition to this, the processing conditions include the nozzle diameter, which is the opening diameter of the nozzle 36, the laser output of the laser oscillator 10, the pulse conditions (frequency, duty) of the laser light, the type and pressure of the assist gas, and the focal length of the focusing lens 34. and so on. The machining conditions held by the machining condition holding unit 80 are used by the machining control unit 70 .

The machining program holding unit 85 holds a machining program for cutting the sheet metal W. As shown in FIG. The machining program held by the machining program holding unit 85 is used by the machining control unit 70 .

The machining condition processing unit 90 sets the machining conditions held by the machining condition holding unit 80 . The machining condition processing unit 90 includes a theoretical value calculator 91 , a parameter adjuster 92 and a machining condition setter 93 .

The theoretical value calculator 91 calculates the theoretical value of the cutting speed based on the theoretical cutting speed formula for calculating the theoretical value of the cutting speed according to the material and thickness of the sheet metal W. The cutting speed theoretical formula will be described with reference to FIG. In FIG. 3, the incident diameter of the laser light (laser beam) incident on the converging lens 34 is D, and the sheet metal W is irradiated with the laser light converged by the converging lens 34 .

PL (W) (W=J/s) is the laser output, A is the laser absorptance, which is the absorptivity of the laser beam to the sheet metal W, and Em is the melting energy, which is the energy for melting (including evaporation) of the sheet metal W. J/cm3), the kerf width is Wk (mm), and the sheet metal thickness is tc (mm). The theoretical value of the cutting speed (hereinafter referred to as "theoretical cutting speed") Vc (cm/s) is defined as follows from the theoretical cutting speed formula shown in Equation (1).

Vc=PL×A/(Em×Wk×tc) (1)
Equation (1) assumes that all the energy is absorbed in the cutting front of the cutting kerf and that there is no heat conduction loss through the sheet metal W. Also, equation (1) assumes that the molten metal in the cutting kerf is completely evacuated by the assist gas.

As shown in formula (1), the theoretical formula for cutting speed is composed of parameters of laser output PL, laser absorptivity A, melting energy Em, kerf width Wk, and plate thickness tc. It can be seen that the theoretical cutting speed Vc is proportional to the laser output PL and laser absorptance A, and inversely proportional to the melting energy Em, kerf width Wk and plate thickness tc.

The parameter adjuster 92 adjusts the laser absorptance A among the parameters constituting the cutting speed theoretical formula to correct the cutting speed theoretical formula.

The machining condition setting unit 93 sets the cutting speed of the machining condition based on the cutting speed theoretical formula corrected by the parameter adjusting unit 92 .

A procedure for setting machining conditions by the machining condition processing unit 90 will be described below with reference to FIG. This processing condition setting procedure is started when the user operates the operation display unit 50 to execute a predetermined operation item (for example, "setting of processing conditions").

In step S10, the theoretical value calculator 91 acquires information necessary for setting processing conditions. The information acquired by the theoretical value calculator 91 includes information on the laser beam, information on the sheet metal W, and information on the processing conditions.

As shown in FIG. 5, the information about the laser light includes the minimum condensing radius r0 (mm), the Rayleigh length Zr (mm), the constant representing the quality of the laser light, and the like. The minimum condensing radius r0 is the radius of the light beam that is the minimum (its diameter d) at the focal position of the converging lens 34 (the focal length f of the converging lens 34). The Rayleigh length Zr is the distance between the position where the cross-sectional area of the light beam is twice the cross-sectional area at the focal length f and the focal position of the light beam. A constant representing the quality of laser light is, for example, BPP (mm·mrad). BPP is called a beam parameter product, and is the product of the minimum condensing radius r0 and the divergence angle α of the laser light after the focal length f.

The information about the sheet metal W includes the material such as mild steel, stainless steel or aluminum, the sheet thickness tc, and the like. A plurality of plate thicknesses tc are prepared for one material.

The information on processing conditions is information on processing conditions other than the cutting speed, such as laser output, processing focus, nozzle diameter, type and pressure of assist gas, and nozzle gap. Here, the processing focus is the distance between the upper surface of the sheet metal W and the focus position in the vertical direction (thickness direction of the sheet metal W). The nozzle gap is the gap between the nozzle 36 in the processing head 35 and the upper surface of the sheet metal W.

These pieces of information are input to the NC unit 60 by the user operating the operation display unit 50, for example. Alternatively, these pieces of information are generated by a computer and input to the NC device 60 through communication. The theoretical value calculator 91 acquires the information input to the NC device 60 in this way.

In step S11, the theoretical value calculator 91 calculates the incident angle φin for each plate thickness tc. In FIG. 6, the cutting front is indicated by F and the processing focus by fp. The angle between the direction of incidence of the laser beam and the direction orthogonal to the cutting front F is the angle of incidence φin. Here, the incident angle φin is generally the angle formed by the laser beam and the perpendicular to the surface irradiated with the laser beam. The angle formed with F is the incident angle φin. The incident angle φin is calculated from the optical properties of laser light. Let rT be the beam radius on the upper surface of the sheet metal W, and rB be the beam radius on the lower surface of the sheet metal W. As shown in FIG. The incident angle φin is represented by Equation (2).

φin=arctan(tc/(rT+rB)) (2)
In step S12, the theoretical value calculator 91 calculates the average absorption rate Aave for each plate thickness tc. The average absorptance Aave indicates the laser absorptivity A with respect to the incident angle φin calculated in step S11. The theoretical value calculator 91 calculates the average absorptance Aave based on the refractive index of the sheet metal W, the absorption coefficient of the sheet metal W, and the incident angle φin for each plate thickness tc. By this calculation, the average absorptance Aave for each plate thickness tc is obtained as shown in FIG.

In step S13, the theoretical value calculator 91 calculates the average kerf width Wk_ave for each plate thickness tc. As shown in FIG. 8, the average kerf width Wk_ave is calculated from the optical characteristics of laser light. Specifically, the average kerf width Wk_ave is determined by the beam diameter (rT×2) on the upper surface of the sheet metal W, the beam diameter (rB×2) on the lower surface of the sheet metal W, and the beam diameter (r0×2) at the focal position. Based on this, it is represented by the formula ( 3 ).

Wk_ave=2×(rT+r0+rB)/3 (3)
In step S14, the theoretical value calculator 91 calculates the theoretical cutting speed Vcal for each plate thickness tc. The theoretical cutting speed Vcal (m/min) is represented by Equation (4) in accordance with the basic equation shown in Equation (1).

Vcal=PL×Aave/(Em×Wk_ave×tc×1000×60) (4)
In step S15, the parameter adjuster 92 acquires cutting data. The cutting data is obtained by cutting the sheet metal W under optimum conditions and experimentally obtaining the optimum value of the cutting speed for a predetermined plate thickness tc (hereinafter referred to as the "optimum cutting speed"). The cutting data is input to the NC device via the operation display unit 50, for example. Alternatively, the cutting data is generated by a computer and input to the NC device 60 through communication. The parameter adjuster 92 acquires the information input to the NC device 60 in this way.

In step S16, the parameter adjuster 92 compares the optimum cutting speed with the theoretical cutting speed Vcal. In FIG. 9, the relationship between the plate thickness tc and the theoretical cutting speed Vcal is indicated by a solid line, and the optimum cutting speed for a given plate thickness tc is plotted by circles. The theoretical cutting speed Vcal deviates from the optimum cutting speed at several plate thicknesses tc. The parameter adjustment section 92 displays the comparison result on the operation display section 50 . The comparison result displayed on the operation display unit 50 is a graph showing the relationship between the plate thickness tc and the cutting speed as shown in FIG. The parameter adjustment unit 92 may obtain the difference between the optimum cutting speed and the theoretical cutting speed Vcal for each plate thickness tc as a comparison result.

In step S17, the parameter adjuster 92 sets a corrected absorptance Aave_am for adjusting the average absorptance Aave. By replacing the average absorption rate Aave in the cutting speed theoretical formula with this corrected absorption rate Aave_am, the cutting speed theoretical formula can be corrected (equation (5)). That is, by adjusting the average absorptance Aave, the cutting speed theoretical formula can be corrected.

Vcal=PL×Aave_am/(Em×Wk_ave×tc×1000×60) (5)
The corrected absorption rate Aave_am for each plate thickness tc is input to the NC device 60 by the user operating the operation display unit 50 . Alternatively, the corrected absorption rate Aave_am for each plate thickness tc is input to the NC device 60 from an external computer. The parameter adjuster 92 sets the corrected absorption rate Aave_am for each plate thickness tc from the information thus input to the NC device 60 .

For example, the user operates the operation display unit 50 to input an adjustment amount such as "+10%" or "-10%." When "+10%" is input, the parameter adjustment unit 92 sets a value that is 10% higher than the theoretical average absorption rate Aave as the corrected absorption rate Aave_am. On the other hand, if "-10%" is specified, the parameter adjuster 92 sets a value obtained by subtracting 10% from the average absorptance Aave as the corrected absorptance Aave_am. In FIG. 10, the average absorptance Aave before adjustment is indicated by a dashed line, and the average absorptance Aave after adjustment, that is, the corrected absorptance Aave_am is indicated by a solid line.

In step S18, the parameter adjuster 92 determines whether or not to end the adjustment of the corrected absorption rate Aave_am. For example, when there are cut data for N times, the processing of steps S16 and S17 is repeated for all the cut data. When the adjustment is finished, an affirmative determination is made in step S18, and the process proceeds to step S19. On the other hand, if the adjustment is not finished, a negative determination is made in step S18, and the process returns to step S16.

In step S19, the parameter adjustment unit 92 replaces the average absorption rate Aave in the theoretical cutting speed formula with the corrected absorption rate Aave_am set in step S17, thereby reconstructing the theoretical cutting speed formula (see formula (5) ). In FIG. 11, the theoretical cutting speed Vcal obtained from the theoretical cutting speed formula reconstructed from the corrected absorption rate Aave_am is indicated by a solid line, and the optimum cutting speed is plotted by circles. As can be seen from FIG. 11, the theoretical cutting speed Vcal corrected by the corrected absorption rate Aave_am accurately matches the optimum cutting speed.

When the cutting speed theoretical formula is reconstructed in this way, the processing condition setting unit 93 associates the processing conditions acquired in step S10 with the cutting speed theoretical formula corrected by the parameter adjusting unit 92, and , is stored in the processing condition holding unit 80 . Based on the information stored in the processing condition holding unit 80, the processing condition setting unit 93 sets the processing conditions corresponding to the material and thickness of the sheet metal W, that is, the processing method, processing focus, correction absorption rate, laser output, cutting. Velocity, gas pressure, nozzle gap, etc. can be set. As shown in FIG. 12 , the set processing conditions are displayed on the operation display section 50 . Since the processing conditions according to this embodiment are generalized by the cutting speed theoretical formula, processing speeds corresponding to various laser outputs can be set at once.

Specific examples will be described below. First, cutting data on the optimum cutting speed was collected for a plurality of sheet metals W having different materials and thicknesses tc. The material of the sheet metal W is stainless steel and aluminum. Further, the plate thickness tc of the sheet metal W is 3 mm to 25 mm for both stainless steel and aluminum. Also, the laser outputs are 6 kW and 9 kW.

On the other hand, the known physical property values of the sheet metal W (refractive index, absorption coefficient, and melting energy Em), and parameters that can be defined by experimental conditions (minimum light collection radius r0, processing focus fp, incident angle φin, and average kerf width Wk_ave ), the average absorptance Aave for each plate thickness tc is calculated. Then, the theoretical cutting speed Vcal for each plate thickness tc was obtained and compared with the cutting data.

In FIG. 13, the material of the sheet metal W is stainless steel, and the laser output PL is 6 kW. Further, in FIG. 15, the material of the sheet metal W is stainless steel, and the laser output PL is 9 kW. In both FIGS. 13 and 15, the solid line is the theoretical cutting speed Vcal for each plate thickness tc, and the circular marks are cutting data (optimum cutting speed) for each plate thickness tc.

In FIGS. 13 and 15, there is no large deviation between the theoretical cutting speed Vcal and the cutting data, and the results of the two are almost the same. However, each laser output PL has a slight deviation at plate thicknesses of 3 to 6 mm. Therefore, the average absorption coefficient Aave is adjusted with respect to the plate thickness tc so as to reduce the error between the cutting data and the theoretical cutting speed Vcal. FIG. 14 shows the adjustment result for FIG. 13, and FIG. 16 shows the adjustment result for FIG. As shown in FIGS. 13 and 15, it can be seen that the corrected theoretical cutting speed formula (corrected theoretical cutting speed Vcal) accurately matches the cutting data. In order to improve the correction accuracy of the theoretical cutting speed Vcal (cutting speed theoretical formula), it is desirable to repeat the cutting experiment as much as possible and use a large amount of cutting data to improve the adjustment accuracy of the average absorption rate Aave. . Thereby, laser cutting can be stabilized.

In FIG. 17, the material of the sheet metal W is aluminum, and the laser output PL is 6 kW. Further, in FIG. 19, the material of the sheet metal W is aluminum, and the laser output PL is 9 kW. In both FIGS. 17 and 19, the solid line is the theoretical cutting speed Vcal for each plate thickness tc, and the circle marks are cutting data (optimum cutting speed) for each plate thickness tc.

17 and 19, there is no large deviation between the theoretical cutting speed Vcal and the cutting data, but there is a slight deviation depending on the plate thickness tc. Therefore, the average absorption coefficient Aave is adjusted with respect to the plate thickness tc so as to reduce the error between the cutting data and the theoretical cutting speed Vcal. FIG. 18 shows the adjustment result for FIG. 17, and FIG. 20 shows the adjustment result for FIG. As shown in FIGS. 18 and 20 , it can be seen that the corrected theoretical cutting speed formula (corrected theoretical cutting speed Vcal) accurately matches the cutting data.

In the theoretical formula for the cutting speed, the average absorptivity Aave of the sheet metal W is a physical property value that depends on the wavelength of 1 μm of the fiber laser. 99”. Similarly, in the case of aluminum, the average absorption coefficient Aave of the sheet metal W was obtained from the refractive index "1.02" and the absorption coefficient "9.43".

Thus, the average absorptance Aave in the cutting speed theoretical formula is based on theoretical physical property values. Therefore, when the sheet metal W is actually laser-processed, the average absorption rate Aave varies due to factors such as the surface condition of the sheet metal W. Therefore, in the present embodiment, the accuracy of the theoretical cutting speed formula is improved by adjusting the average absorption rate Aave as a correction parameter to correct the theoretical cutting speed formula.

As described above, in the laser processing machine 100 of the present embodiment, the NC device 60 has a theoretical value calculation section 91, a parameter adjustment section 92, and a processing condition setting section. The theoretical value calculator 91 calculates the theoretical cutting speed Vcal based on the theoretical cutting speed formula for calculating the theoretical value of the cutting speed according to the material of the sheet metal W and the plate thickness tc. The parameter adjuster 92 adjusts the parameters forming the cutting speed theoretical formula to correct the cutting speed theoretical formula. The machining condition setting unit 93 sets machining conditions including the cutting speed calculated based on the cutting speed theoretical formula corrected by the parameter adjusting unit 92 . The cutting speed theoretical formula includes an average absorptance Aave (absorptivity of laser light to the sheet metal W) as a parameter that can be adjusted by the parameter adjuster 92 .

According to this configuration, the cutting speed can be generalized with respect to the material and the plate thickness tc by the cutting speed theoretical formula, so the cutting speed corresponding to the material and the plate thickness tc of the sheet metal W can be calculated from the cutting speed theoretical formula can be done. Therefore, as shown in FIG. 12 , the processing conditions including the cutting speed can be set from the cutting speed theoretical formula. As a result, it is possible to save the trouble of creating individual processing condition files for each combination of the material quality and plate thickness tc. As a result, the laser processing machine 100 can set processing conditions with a shorter man-hour.

Further, by adjusting the average absorptance Aave in this cutting speed theoretical formula, the cutting speed theoretical formula can be corrected. As a result, the deviation existing in the theoretical cutting speed can be adjusted, so that the optimum cutting speed can be set as the processing condition.

In the example shown in FIG. 12 , the processing conditions are associated with the post-adjustment average absorptance Aave (that is, the corrected absorptance Aave_am). However, since the absorption rate of the sheet metal W differs depending on the material, material manufacturer, or material production country, the corrected absorption factor Aave_am can be stored in a separate table for each combination of material, material manufacturer, and material production country. be. In this case, in addition to the corrected absorptance Aave_am, the material maker and material production country may be entered in the table.

In the present embodiment, the theoretical formula for cutting speed is constructed using the laser output PL of the laser oscillator 10, the average absorption rate Aave, the melting energy Em, the average kerf width Wk_ave, and the plate thickness tc of the material as parameters. Specifically, the cutting speed theoretical formula is as shown in formula (4) above.

According to this configuration, since the cutting speed can be generalized by the cutting speed theoretical formula, the cutting speed corresponding to the material of the sheet metal W and the plate thickness tc can be calculated by the cutting speed theoretical formula. As a result, machining conditions can be set with a shorter man-hour.

As shown in equation (4), the parameters constituting the theoretical cutting speed Vcal include the laser power PL, the melting energy Em, and the average kerf width Wk_ave in addition to the average absorption rate Aave.

The laser output PL has an upper limit depending on the performance of the laser oscillator 10 . Therefore, correction cannot be performed beyond the upper limit of the performance of the laser oscillator 10 . Moreover, when performing correction beyond the upper limit, a combination with other parameters is required. Therefore, it is unsuitable as a parameter to be adjusted by the parameter adjusting section 92 .

Also, changing the kerf width affects the outer shape of the product. Therefore, the average kerf width Wk_ave cannot be simply changed. Therefore, it is unsuitable as a parameter to be adjusted by the parameter adjusting section 92 .

On the other hand, for the average absorption Aave, the parameter is percentage. Therefore, when setting the corrected absorption rate Aave_am, the input is easy for the user to understand, and the correction can be performed easily. In addition, when correcting the average absorption rate Aave, different plate thicknesses tc can be handled, which is highly convenient. For this reason, it is preferable to use the average absorption rate Aave as the adjustment parameter.

Although it is considered best to use the average absorptivity Aave whose percentage is a parameter, it is also possible to adjust the melting energy Em and correct the cutting theoretical formula.

In addition, in the embodiment described above, it is assumed that the laser processing machine 100 uses nitrogen as the assist gas. However, oxygen can also be used as the assist gas. When using oxygen as the assist gas, it is necessary to consider the oxidation reaction energy. When the oxidation reaction energy is E02, the theoretical cutting speed Vcal (m/min) is expressed by Equation (6).

Vcal=(PL*Aave+E02)/(Em*Wk_ave*tc*1000*60) (6)

In addition, the laser processing machine 100 of this embodiment further has an operation display unit 50 operated by the user to input information. In this case, the parameter adjustment section 92 adjusts the average absorption rate Aave according to the information input to the operation display section 50 .

According to this configuration, deviations occurring in the theoretical cutting speed Vcal can be compensated according to the information input by the user. Thereby, the optimum cutting speed can be set as the processing condition.

In the above-described embodiment, the user himself/herself adjusts the average absorption rate Aave. However, the parameter adjuster 92 may adjust the average absorption rate Aave so that the theoretical cutting speed Vcal approaches the optimum cutting speed.

According to this configuration, it is possible to automatically compensate for the deviation between the optimum cutting speed and the theoretical cutting speed. As a result, the optimum cutting speed Vcal can be automatically set for the machining conditions.

Incidentally, in the present embodiment, the situation in which the processing conditions are initially set in the processing condition holding unit 80 has been described. However, the processing condition processing unit 90 may perform the setting method described above when updating the initially set processing conditions.

(Second embodiment)
A laser processing machine 100 according to the second embodiment will be described below. The laser processing machine 100 according to the second embodiment differs from that of the first embodiment in that it monitors the processing state and corrects the cutting speed theoretical formula based on this information. .

In FIG. 21, the laser oscillator 10 has an output monitor 15 that monitors the output of laser light. The laser processing unit 20 also has an output measuring section 25 , a processing monitoring section 26 and a kerf width detecting section 27 . The output measuring unit 25 measures the output of the laser beam actually applied to the processing point. The machining monitoring unit 26 is attached to the machining head 35, measures the light emitted during machining, and determines the quality of the machining. The kerf width detection unit 27 includes imaging means such as a camera attached to the processing head 35, and measures the actual kerf width actually processed based on the captured image of the processing point.

In the laser processing machine 100 having such a configuration, the parameter adjusting section 92 corrects the laser output PL in the cutting speed theoretical formula according to the laser output monitored by the output monitoring section 15 of the laser oscillator 10 . Then, the machining condition setting unit 93 resets the machining conditions including the cutting speed based on the cutting speed theoretical formula corrected by the parameter adjusting unit 92 . This makes it possible to reflect the deterioration of the laser oscillator 10 over time, the decrease in output due to failure of the laser diode, etc. in the processing conditions (cutting speed theoretical formula).

Note that the laser output correction is not limited to the laser output monitored by the output monitoring unit 15 of the laser oscillator 10, and information obtained from the output measuring unit 25 of the laser processing unit 20 may be used.

In addition, the parameter adjustment unit 92 learns the corrected absorption rate Aave_am based on the result of the processing quality determination by the processing monitoring unit 26 . For example, when the machining monitoring unit 26 determines that the machining is defective, the parameter adjusting unit 92 corrects the average absorptance Aave and learns the corrected absorptance Aave_am that provides a good machining result. Then, the machining condition setting unit 93 resets the machining conditions including the cutting speed based on the cutting speed theoretical formula corrected by the parameter adjusting unit 92 . This makes it possible to reflect the deterioration of the laser oscillator 10 over time, the decrease in output due to failure of the laser diode, etc. in the processing conditions (cutting speed theoretical formula).

On the other hand, the theoretical value calculator 91 compares the average kerf width Wk_ave specified in the calculation of the cutting speed theoretical formula with the actual kerf width detected by the kerf width detector 27 . Then, when there is a deviation between the average kerf width Wk_ave and the actual kerf width, for example, when the actual kerf width is more than twice the average kerf width Wk_ave, the theoretical value calculation unit 91 changes the operation display unit 50 to Control and output an alarm. The theoretical value calculator 91 may also learn the corrected absorption rate Aave_am based on the deviation between the average kerf width Wk_ave and the actual kerf width.

As described above, according to the present embodiment, it is possible to learn the processing results for the sheet metal W. FIG. By correcting the parameters of the cutting speed theoretical formula based on this learning result, it is possible to correct the theoretical value of the cutting speed according to the actual situation such as aging of the laser processing machine 100 . Thereby, the adjustment of the laser processing machine can be automatically performed.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention. For example, the laser processing machine may perform control such that the laser beam has an optimum trajectory when cutting the workpiece .

REFERENCE SIGNS LIST 100 laser processing machine 10 laser oscillator 12 process fiber 20 laser processing unit 30 collimator unit 34 focusing lens 35 processing head 36 nozzle 40 assist gas supply device 50 operation display unit 60 NC device 70 processing control unit 80 processing condition holding unit 85 processing program holding unit Section 90 Machining Condition Processing Unit 91 Theoretical Value Calculating Section 92 Parameter Adjusting Section 93 Machining Condition Setting Section 93

Claims (3)

a laser processing unit that cuts a material using a laser beam emitted from a laser oscillator;
A control device for controlling the laser processing unit according to processing conditions including cutting speed,
The laser processing unit is
a kerf width detection unit that detects an actual kerf width processed by the laser processing unit;
The control device is
a theoretical value calculation unit that calculates the theoretical value of the cutting speed based on a theoretical cutting speed formula for calculating the theoretical value of the cutting speed according to the material and plate thickness of the material;
a parameter adjustment unit that adjusts the parameters that make up the theoretical cutting speed formula and corrects the theoretical cutting speed formula;
a processing condition setting unit that sets the processing conditions including the cutting speed calculated based on the cutting speed theoretical formula corrected by the parameter adjustment unit ;
The theoretical formula for cutting speed has, as a parameter that can be adjusted by the parameter adjusting unit, a correction absorptance for adjusting the average absorptivity of the laser beam to the material,
The theoretical value calculation section compares the average kerf width specified in the calculation of the cutting speed theoretical formula with the actual kerf width detected by the kerf width detection section, and determines the average kerf width and the actual kerf width. Learning the corrected absorption rate based on the deviation from
Laser processing machine. The laser processing unit further includes a processing monitoring unit that determines the quality of processing by the laser processing unit,
The parameter adjusting unit learns the corrected absorption rate based on the processing quality determination result by the processing monitoring unit.
The laser processing machine according to claim 1. When the theoretical value of the cutting speed is Vcal, the laser output of the laser oscillator is PL, the melting energy that is the energy for melting the material is Em, the average kerf width is Wk_ave, and the plate thickness of the material is tc,
The corrected absorption rate is a percentage of Aave_am given by the formula:
Vcal=PL*Aave_am/(Em*Wk_ave*tc*1000*60)
3. The laser processing machine according to claim 1 or 2.

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