JP7373339B2 - laser processing machine - Google Patents

Description

The present invention relates to a laser processing machine.

2. Description of the Related Art Laser processing machines that cut sheet metal with a laser beam emitted from a laser oscillator to produce products having a predetermined shape are in widespread use. When a laser beam machine cuts a thick mild steel plate, excessive temperature rise of the material may cause burning, resulting in poor cutting. Patent Document 1 describes a laser processing machine configured to suppress the occurrence of burning.

Japanese Patent Application Publication No. 2015-91592

The degree of burning that may occur when cutting sheet metal varies depending on various conditions. It is not preferable to take measures to excessively suppress the occurrence of burning when only a small amount of burning occurs. Furthermore, it is also undesirable that when a large amount of burning occurs, measures to suppress the occurrence of burning are insufficient. It is required to take appropriate measures to suppress the occurrence of burning depending on the degree of burning.

An object of the present invention is to provide a laser processing machine that can appropriately take measures to suppress the occurrence of burning depending on the degree of burning.

The present invention provides a laser oscillator that emits a laser beam, a processing head that irradiates a sheet metal to be processed with the laser beam emitted by the laser oscillator, and a processing head that moves the processing head relative to a surface of the sheet metal. A laser processing unit that has a moving mechanism and cuts the sheet metal, and a plurality of sheet metals having different contents of compositional elements, depending on the copper content or a combination of the copper content and the manganese content. a storage unit that stores a setting table that classifies the sheet metal into a plurality of material types according to the material type and associates measures for suppressing the occurrence of burning for each of the plurality of material types, and a sheet metal processing unit that uses the laser processing unit to When attempting to cut, refer to the setting table, select a countermeasure corresponding to the material type of the sheet metal to be cut, and cut the sheet metal while applying the selected countermeasure to suppress the occurrence of burning. A laser processing machine is provided, which includes a control device that controls the laser beam processing machine to perform the following operations .

According to the laser processing machine of the present invention, it is possible to appropriately take measures to suppress the occurrence of burning depending on the degree of burning.

FIG. 1 is a diagram showing an example of the overall configuration of a laser processing machine according to an embodiment. FIG. 7 is a diagram showing a test shape used when verifying the number of occurrences of burning. This is a table summarizing the number of occurrences of burning verified with multiple materials. It is a table showing the content of compositional elements of a plurality of materials. FIG. 3 is a diagram showing a setting table showing measures for suppressing the occurrence of burning set for each material type, which is used by the laser processing machine of one embodiment. It is a figure which shows the example of the angle of the edge when cutting a sheet metal. FIG. 2 is a flowchart illustrating a process for selecting a measure to suppress the occurrence of burning when a laser processing machine according to an embodiment cuts a sheet metal. FIG.

Hereinafter, a laser processing machine according to an embodiment will be described with reference to the accompanying drawings. First, the overall configuration and operation of a laser processing machine 100, which is a laser processing machine of one embodiment, will be described using FIG. 1.

In FIG. 1, a laser processing machine 100 includes a laser oscillator 10 that generates and emits a laser beam, a laser processing unit 20, and a process fiber 12 that transmits the laser beam emitted from the laser oscillator 10 to the laser processing unit 20. Equipped with.

The laser processing machine 100 also includes an operation unit 40, an NC device 50, a processing program database 60, a processing condition database 70, an assist gas supply device 80, and a cooling water spray device 90. The NC device 50 is an example of a control device that controls each part of the laser processing machine 100.

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

The laser oscillator 10 emits a laser beam 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 a laser beam with a wavelength of 1060 nm to 1080 nm, and the DDL oscillator emits a laser beam with a wavelength of 910 nm to 950 nm. The carbon dioxide laser oscillator emits a laser beam with a wavelength of 10.6 μm.

The laser processing unit 20 includes a processing table 21 on which a sheet metal W to be processed is placed, a gate-shaped X-axis carriage 22, a Y-axis carriage 23, a collimator unit 30 fixed to the Y-axis carriage 23, and a processing head 35. has. The X-axis carriage 22 is configured to be movable on the processing table 21 in the X-axis direction. The Y-axis carriage 23 is configured to be movable on the X-axis carriage 22 in the Y-axis direction perpendicular to the X-axis. The X-axis carriage 22 and the Y-axis carriage 23 serve as moving mechanisms for moving the processing head 35 along the surface of the sheet metal W in the X-axis direction, the Y-axis direction, or any combination direction of the X-axis and the Y-axis. Function.

Instead of moving the processing head 35 along the surface of the sheet metal W, the processing head 35 may be configured to be fixed in position and the sheet metal W may be moved. The laser processing machine 100 only needs to include a movement mechanism that moves the processing head 35 relative to the surface of the sheet metal W.

The collimator unit 30 includes a collimation lens 31, a bend mirror 32, and a focusing lens 33. The collimation lens 31 converts the diverging laser beam emitted from the process fiber 12 into parallel light (collimated light). The bend mirror 32 reflects the laser beam converted into parallel light by the collimation lens 31 downward in the Z-axis direction. The focusing lens 33 focuses the laser beam reflected by the bend mirror 32 and converts it into convergent light.

A nozzle 36 having a circular opening 36a at its tip and emitting a laser beam from the opening 36a is attached to the processing head 35. The laser beam converted into convergent light by the converging lens 33 is emitted from the opening 36a of the nozzle 36 and irradiated onto the sheet metal W.

The assist gas supply device 80 supplies nitrogen, oxygen, a mixed gas of nitrogen and oxygen, or air to the processing head 35 as an assist gas. When processing the sheet metal W, the assist gas is blown onto the sheet metal W through the opening 36a. The assist gas discharges the molten metal within the kerf width where the sheet metal W is melted. In order to suppress the occurrence of burning, the cooling water spray device 90 may supply cooling water to the processing head 35 while cutting the sheet metal W, and spray the cooling water onto the sheet metal W from the opening 36a.

As a first verification, the inventor confirmed the cause of burning. A general structural rolled steel material (SS400) with a plate thickness of 25 mm was used as the sheet metal W, and 24 products of the same shape were continuously cut from one sheet metal W using the laser processing machine 100. When the cooling water was not sprayed, no burning occurred when cutting the first product, but burning occurred when cutting the final 24th product. When 24 products were continuously cut while spraying cooling water, no burning occurred from the 1st product to the 24th product.

According to the first verification, the cause of the burning is thought to be an increase in the temperature of the material due to the accumulation of heat generated when the sheet metal W is cut by a laser beam.

As a second verification, the inventor cut a thick plate of mild steel plate as the sheet metal W using the laser processing machine 100, and verified how burning was suppressed depending on the spray flow rate of cooling water. As shown in FIG. 2, piercings Ps were made in the sheet metal W using the laser processing machine 100, and the sheet metal W was cut into a substantially rectangular shape by cutting surfaces 1 to 4. The length of cut surfaces 1 to 4 is 50 mm.

Three types of materials were cut as sheet metal W: SS400, rolled steel for welded structures (SM490A), and rolled steel for building structures (SN490B). In both cases, the plate thickness is 28 mm. The processing conditions were as follows: the focal length of the focusing lens 33 was 190 mm, the laser output of the laser oscillator 10 was 9 kW, the oscillation frequency was 1 kHz, the duty was 75%, the assist gas pressure was 0.07 MPa, and the gap was 1.0 mm.

FIG. 3 shows the verification results for SS400, SM490A, and SN490B. When SS400 was cut by the laser processing machine 100, the number of burning occurrences was 2, 0, 1, and 3 on cut surfaces 1 to 4, respectively, for a total of 6 when cooling water was not sprayed. When the cooling water spray flow rate was set to the standard 20 cc/min, the number of burning occurrences on cut surfaces 1 to 4 was 0, 0, 0, and 1, respectively, for a total of 1. When the spray flow rate of the cooling water was set to a relatively high rate of 50 cc/min, the number of occurrences of burning on cut surfaces 1 to 4 was all 0, which was 0 in total. The inventor visually confirmed the number of burns that occurred on each cut surface. Note that the reason why the number of burns occurring on the cut surface 4 increases is that heat is accumulated on the cut surface 4 during cutting.

When SM490A was cut by the laser processing machine 100, when cooling water was not sprayed, the number of burns occurring on cut surfaces 1 to 4 was 2, 1, 0, and 6, respectively, for a total of 9. When the cooling water spray flow rate was set to the standard 20 cc/min, the number of burning occurrences on cut surfaces 1 to 4 was 0, 1, 0, and 6, respectively, for a total of 7. When the spray flow rate of the cooling water was set to a rather high rate of 50 cc/min, the number of burning occurrences on cut surfaces 1 to 4 was 0, 0, 0, and 1, respectively, for a total of 1.

When SN490B was cut by the laser processing machine 100, the number of burning occurrences was 1, 2, 3, and 3 on cut surfaces 1 to 4, respectively, for a total of 9 when cooling water was not sprayed. When the cooling water spray flow rate was set to the standard 20 cc/min, the number of burning occurrences on cut surfaces 1 to 4 was 1, 0, 2, and 2, respectively, for a total of 5. When the spray flow rate of the cooling water was set to a relatively high rate of 50 cc/min, the number of burning occurrences on cut surfaces 1 to 4 was 0, 0, 0, and 2, respectively, for a total of 2.

From FIG. 3, it can be seen that the more the cooling water spray flow rate is increased, the more the occurrence of burning can be suppressed. From the verification results of SS400, SM490A, and SN490B, it can be seen that the number of occurrences of burning differs depending on the material of the sheet metal W. In SS400, the occurrence of burning can be suppressed at a cooling water spray flow rate of 20 cc/min. However, in SM490A and SN490B, the cooling water spray flow rate of 20 cc/min is insufficient and needs to be 50 cc/min or more. That is, it can be seen that the appropriate spray flow rate of cooling water differs depending on the material of the sheet metal W.

Furthermore, as a third verification, the inventor used an X-ray analyzer to analyze the compositional elements of SS400, SM490A, and SN490B, and determined the relationship between the content of each element and the ease with which burning occurs. was verified. As shown in Figure 4, Cr (chromium), Mn (manganese), Ni (nickel), Cu (copper), and Mo (molybdenum) were selected from among the elements that could be detected by the X-ray analyzer. Indicates the content of FIG. 4 shows the thermal conductivity of each element.

As can be seen from FIG. 4, SS400 has a high content of Cu, which has a significantly higher thermal conductivity than that of other elements. In SM490A and SN490B, the Cu content is 0. SM490A and SN490B have a high content of Mn, whose thermal conductivity is significantly lower than that of other elements. In SS400, the Mn content is less than 1/2 of the content in SM490A and SN490B.

When a large amount of Cu, which has high thermal conductivity, is included, heat during cutting of the sheet metal W is easily conducted to the surrounding area, so that burning is less likely to occur. If a large amount of Mn, which has low thermal conductivity, is included, heat during cutting of the sheet metal W is difficult to conduct to the surrounding area, so that burning is likely to occur. As shown in FIG. 3, it can be understood that the reason why more burning occurs in SM490A and SN490B than in SS400 is due to the difference in content of Cu and Mn. The content of Cu and Mn contained in the material of the sheet metal W serves as an index of whether or not burning is likely to occur.

As described above, the following findings were found through the first to third verifications. The first verification indicates that excessive temperature rise of the material due to heat accumulation is the cause of burning. The second verification revealed that increasing the spray flow rate of cooling water is effective in suppressing the occurrence of burning, and the appropriate spray flow rate of cooling water differs depending on the material. According to the third verification, the content of elements (particularly Cu and Mn) contained in the material becomes an index of whether or not burning is likely to occur.

As shown in FIG. 5, in this embodiment, a plurality of sheet metals having different contents of compositional elements are classified into material types A to L. The materials A to L differ in the degree of ease with which burning occurs when the sheet metal is cut by the laser processing unit 20.

Material A has a Cu content of more than 0.20% and is a material that is unlikely to cause burning. Material B has a Cu content of 0.20% or less (and exceeds 0.10%) and is a material that is more likely to cause burning than material A. Material C has a Cu content of 0.10% or less and is a material that is more likely to cause burning than material B. Material D has a Cu content of 0.10% or less and a Mn content of 0.10% or more, and is a material that is more likely to cause burning than material C.

Material E has a Cu content of 0.05% or less and a Mn content of 0.10% or more, and is a material that is more likely to cause burning than material D. Material F has a Cu content of 0.05% or less and a Mn content of 0.50% or more, and is a material that is more likely to cause burning than material E. Material G has a Cu content of 0.05% or less and a Mn content of 0.75% or more, and is a material that is more likely to cause burning than material F. Material H has a Cu content of 0.05% or less and a Mn content of 1.00% or more, and is a material that is more likely to cause burning than material G.

Material I has a Cu content of 0.0% and a Mn content of 1.00% or more, and is a material that is more likely to cause burning than material H. Material J has a Cu content of 0.0%, a Mn content of 1.00% or more, and a content of elements other than Fe (iron) of 1.0% or more, and has a higher burning resistance than Material I. This is a material that is likely to cause this. Material K has a Cu content of 0.0%, a Mn content of 1.00% or more, and a content of elements other than Fe of 2.0% or more, and is more likely to cause burning than material J. The material is easy to use. Material L has a Cu content of 0.0%, a Mn content of 1.00% or more, and a content of elements other than Fe of 3.0% or more, and is more likely to cause burning than material K. The material is easy to use.

As shown in Fig. 5, it is set whether or not to take measures to suppress the occurrence of burning, depending on the materials A to L. If measures are taken, specific measures to suppress the occurrence of burning are set. It is set. The first measure to suppress the occurrence of burning is to spray cooling water. The second measure is to spray cooling water after temporarily stopping the cutting of the sheet metal W at the edge of the product. The third measure is to adjust the machining condition parameters. In FIG. 5, a column with a hyphen means that no countermeasure is taken.

As a first measure, the spray flow rate of cooling water is set to 20 cc/min for material B, and the spray flow rate of cooling water is set to 40 cc/min for material C. For materials D to L, the spray flow rate of cooling water is set to 60 cc/min.

In the second measure, the spray flow rate and spray time of the cooling water are set in accordance with the angle of the edge when the relative movement of the processing head 35 is temporarily stopped when cutting the edge of the product. has been done. The second measure is set for material types E to L, which are some of the plurality of material types A to L.

FIG. 6 shows an example of the angle of the edge of the product. When the product is hexagonal, one interior angle is 120 degrees. When the product is a square, one interior angle is 90 degrees. When the product is a right triangle, one interior angle is 60 degrees.

For material E, if the angle of the edge of the product is 120 degrees or less, the spray flow rate of cooling water is set to 60 cc/min and the spray time is set to 0.1 second. For material F, if the edge angle of the product is 90 degrees or less, the spray flow rate of cooling water is set to 60 cc/min and the spray time is set to 0.2 seconds. For material G, if the edge angle of the product is 60 degrees or less, the cooling water spray flow rate is set to 60 cc/min and the spray time is set to 0.5 seconds. For materials H to L, if the edge angle of the product is 45 degrees or less, the cooling water spray flow rate is set to 60 cc/min and the spray time is set to 1.0 seconds.

Adjustment of processing condition parameters, which is the third measure, includes reducing the laser output of the laser beam emitted by the laser oscillator 10, increasing the cutting speed when cutting the sheet metal W, and increasing the amount of assist gas supplied by the assist gas supply device 80. Including reduction of gas pressure. The third measure is set for material types I to L, which are some of the plurality of material types A to L. Specifically, a reduction in laser output is set for material types I to L, an increase in cutting speed is set for material types K and L, and a reduction in gas pressure of assist gas is set for material type L.

Adjustment of processing condition parameters is usually used for laser processing, and among the processing conditions that are preset for each material type or plate thickness stored in the processing condition database 70, reduction of laser output, increase of cutting speed, It may be at least one of reducing the gas pressure of the assist gas. Adjustment of the processing condition parameters may be a combination of any two of the following: reducing the laser output, increasing the cutting speed, and reducing the gas pressure of the assist gas. If only one is used, it is preferable to reduce the laser output. When using two, it is preferable to reduce the laser output and increase the cutting speed.

For material I, the laser output is set to be reduced by 1.0%. Material J is set to reduce the laser output by 3.0%. By reducing the laser output, the temperature rise of the sheet metal W can be suppressed, and therefore the occurrence of burning can be suppressed.

For material K, settings are made such that the laser output is reduced by 3.0% and the cutting speed of the sheet metal W is increased by 1.0%. If the cutting speed of the sheet metal W is increased, the temperature rise of the sheet metal W can be suppressed, and therefore the occurrence of burning can be suppressed. For material L, settings were made to reduce the laser output by 3.0%, increase the cutting speed of the sheet metal W by 1.0%, and further reduce the gas pressure of the assist gas by 1.0%. There is. Increasing the gas pressure of the assist gas (oxygen) increases the amount of gas supplied to the molten metal, promoting the oxidation reaction and making it easier for burning to occur. On the other hand, if the gas pressure of the assist gas is lowered, the reaction heat due to oxidation can be reduced, thereby suppressing the occurrence of burning.

The NC device 50 stores a setting table showing measures for suppressing the occurrence of burning associated with each material type shown in FIG. 5 described above. The NC device 50 is a storage unit that stores a setting table. The setting table may be stored in a storage unit other than the NC device 50, and the NC device 50 may refer to the setting table stored in the storage unit.

A process in which the laser processing machine 100 cuts the sheet metal W while taking measures to suppress the occurrence of burning will be explained using the flowchart shown in FIG. In FIG. 7, when starting the process, the operator inputs the component amount of the sheet metal W (mild steel plate) to be processed into the NC device 50 in step S1. The amount of components input to the NC device 50 may be only Cr, Mn, Ni, Cu, and Mo. Note that the operator can check the amount of ingredients in the sheet metal using the mill sheet. Here, manual input is performed by the operator, but it may be configured such that an X-ray analyzer automatically analyzes the amount of each element in the sheet metal W and supplies the result to the NC device 50. Alternatively, the component amounts may be written in advance in the processing program used to cut the sheet metal W, which is stored in the processing program database 60, and the NC device 50 may refer to the component amounts.

In step S2, the NC device 50 determines whether the amount of each component corresponds to any of the registered material types A to L. If each component amount corresponds to one of the registered material types A to L (YES), the NC device 50 reads the setting conditions of the corresponding material type in step S3. The setting conditions are the setting conditions for measures to suppress the occurrence of burning. In step S4, the NC device 50 controls the laser processing machine 100 to cut the sheet metal W to be processed using the processing program stored in the processing program database 60. At this time, the NC device 50 refers to the processing condition database 70, selects processing conditions corresponding to the predetermined material type and plate thickness, and cuts the sheet metal W by applying both the processing conditions and the setting conditions. The laser processing machine 100 is controlled as follows.

The operator checks whether or not burning has occurred in step S5. Instead of the operator visually checking whether or not burning has occurred, the cross section of the sheet metal W may be photographed with a camera to automatically determine whether or not burning has occurred. If burning has not occurred in step S5 (NO), the process of cutting the sheet metal W ends.

If the amount of each component does not correspond to any of the registered material types A to L in step S2 (NO), the operator adds a new material type to the setting table and corresponds to the new material type in step S6. Register the setting conditions that were set. The NC device 50 or the operator executes the processes of steps S3 to S5. Note that if the material type and setting conditions are newly registered in step S6, the setting conditions of the newly registered material type are read in step S3.

If burning has occurred in step S5 (YES), the operator stops the machining, or the NC device 50 automatically stops the machining. When it is automatically determined by a camera or sensor whether or not burning has occurred, when it is determined that burning has occurred, the NC device 50 may stop the processing in response to the determination.

In step S7, the operator changes the countermeasure stored in the setting table corresponding to the currently selected material type to a setting condition that further suppresses the occurrence of burn, and the NC device 50 changes the countermeasure stored in the setting table corresponding to the currently selected material type to a setting condition that further suppresses the occurrence of burn. Update configuration tables in response to operations. The NC device 50 or the operator executes the processes of steps S3 to S5 so as to continue cutting the sheet metal W in which burning has occurred, or to change the sheet metal W to be processed and cut the changed sheet metal W. Note that if the setting table is updated in step S7, the changed setting conditions are read in step S3.

Instead of the operator changing the setting conditions of the setting table and the NC device 50 updating the setting table, the NC device 50 may automatically change the setting table as follows. Taking material type E as an example, assume that burning occurs when cutting a sheet metal W of material type E while suppressing the occurrence of burning under the conditions set in the setting table. At this time, the NC device 50 sets any one of the plurality of measures for the next material type F to the material type E, which suppresses the occurrence of burning more strongly. Further, the NC device 50 may set all of the plurality of measures for material type F to material type E. That is, when burning occurs, the NC device 50 may automatically strengthen measures to suppress the occurrence of burning.

Through the process shown in FIG. 7, the laser processing machine 100 can cut the sheet metal W while suppressing the occurrence of burning by appropriately taking measures to suppress the occurrence of burning depending on the degree of burning. In the example of FIG. 5, by implementing the above-described first measure, the occurrence of burning when cutting the sheet metal W of material types B to L is suppressed. By taking the above-mentioned second measure, the occurrence of burning when cutting the edge of the product by cutting the sheet metal W of material types E to L is suppressed. By implementing the third measure described above, the occurrence of burning when cutting the sheet metal W of material types I to L is more effectively suppressed.

The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the gist of the present invention. The material of the sheet metal W is not limited to SS materials such as SS400, SM materials such as SM490A, and SN materials such as SN490B. The sheet metal W may be made of stainless steel, and even if burning occurs when cutting stainless steel using nitrogen as an assist gas, measures can be taken to similarly suppress the occurrence of burning.

In order to suppress the occurrence of burning, only the first measure, only the second measure, or only the third measure may be taken. Any two of the first to third measures may be combined.

10 Laser oscillator 12 Process fiber 20 Laser processing unit 21 Processing table 22 X-axis carriage (moving mechanism)
23 Y-axis carriage (moving mechanism)
30 collimator unit 31 collimation lens 32 bend mirror 33 focusing lens 35 processing head 36 nozzle 36a opening 40 operation section 50 NC device (storage section, control device)
60 Processing program database 70 Processing condition database 80 Assist gas supply device 90 Cooling water spray device 100 Laser processing machine W Sheet metal

Claims (3)

a laser oscillator that emits a laser beam;
A laser that cuts the sheet metal, the laser having a processing head that irradiates the sheet metal to be processed with a laser beam emitted by the laser oscillator, and a movement mechanism that moves the processing head relatively to the surface of the sheet metal. processing unit,
A plurality of sheet metals with different contents of compositional elements are classified into a plurality of material types according to the copper content or a combination of the copper content and the manganese content, and the plurality of material types are classified. a storage unit that stores a setting table that associates measures to suppress the occurrence of burning for each material type;
When the laser processing unit is to cut a sheet metal, the setting table is referred to, a countermeasure is selected corresponding to the material type of the sheet metal to be cut, and the selected countermeasure is applied to suppress the occurrence of burning. a control device for controlling the sheet metal to be cut while cutting the sheet metal;
A laser processing machine equipped with Further comprising a cooling water spray device that sprays cooling water onto the sheet metal while cutting the sheet metal,
In the setting table, a spray flow rate of cooling water is associated with each material type of the plurality of material types as a measure for suppressing the occurrence of burning of the cooling water sprayed by the cooling water spraying device,
The control device selects a cooling water spray flow rate corresponding to the material type of the sheet metal to be cut, and controls the cooling water spray device to spray the cooling water at the selected spray flow rate. 1. The laser processing machine according to 1. The setting table includes, for each of the plurality of material types, whether or not to reduce the laser output of the laser beam emitted by the laser oscillator, and whether to reduce the laser output as a measure to suppress the occurrence of burning. The adjustment of machining condition parameters including the degree of reduction in time is associated with
The control device determines whether or not to reduce the laser output in accordance with the material type of the sheet metal to be cut, and controls the laser oscillator to provide the unreduced laser output or the reduced laser output. The laser processing machine according to claim 1.

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