Laser processing machine

Abstract

This laser processing machine comprises: a laser head that emits laser; a gap sensor that is held integrally with the laser head and measures the distance to a workpiece; a drive mechanism that moves the laser head and the workpiece relative to each other; and a control device that controls the drive mechanism. The control device includes: a program control unit that generates command values for operating the drive mechanism so that the laser head and the workpiece move relative to each other according to a machining program; a distance adjustment unit that corrects the command values, generated by the program control unit, to keep the measurement value of the gap sensor at a predetermined value during the control by the program control unit; a foreign matter determination unit that determines, on the basis of the measurement value of the gap sensor, whether or not foreign matter is attached to the surface of the workpiece; and a removal control unit that, when the foreign matter determination unit determines that foreign matter is attached, interrupts the control by the program control unit and generates command values for operating the drive mechanism so that the foreign matter is irradiated with the laser.

Description

laser processing machine

[0001] The present invention relates to a laser processing machine.

[0002] Laser processing machines are used to perform processes such as cutting and welding by irradiating a workpiece with a laser by moving a laser head that emits a laser relative to the workpiece according to a processing program. If foreign matter adheres to the surface of the workpiece being processed by such a laser processing machine, the workpiece may not be heated as expected, and the processing may not be performed properly. As a typical example, when cutting a workpiece with a laser, piercing is performed first to form a through hole in the workpiece. During this piercing, melted workpiece material may splash around and adhere to the surface around the formed through hole as foreign matter (spatter).

[0003] In order to remove spatter that adheres due to piercing, it has been proposed to remove the spatter by irradiating a laser onto the area around the formed through hole where spatter may adhere after piercing, thereby ensuring that cutting processing can be performed starting from the through hole (see, for example, Patent Document 1).

[0004] Patent No. 7229441

[0005] Although spatter does not always adhere during piercing, performing an operation to remove spatter after piercing as described in Patent Document 1 causes the inconvenience of lengthening the processing time. Furthermore, the method of Patent Document 1 cannot deal with cases where spatter adheres to a position slightly distant from the workpiece during piercing or where foreign matter other than spatter adheres to the workpiece.

[0006] A laser processing machine according to one aspect of the present disclosure includes a laser head that emits a laser, a gap sensor that is held integrally with the laser head and measures the distance to a workpiece, a drive mechanism that moves the laser head and the workpiece relative to each other, and a control device that controls the drive mechanism. The control device has a program control unit that generates command values ​​to operate the drive mechanism so that the laser head and the workpiece move relative to each other in accordance with a processing program, a distance adjustment unit that, while controlled by the program control unit, corrects the command values ​​generated by the program control unit so as to maintain the measurement value of the gap sensor at a predetermined value, a foreign matter determination unit that determines whether or not a foreign matter is attached to the surface of the workpiece based on the measurement value of the gap sensor, and a removal control unit that, when the foreign matter determination unit determines that the foreign matter is attached, interrupts control by the program control unit and generates a command value to operate the drive mechanism so that the laser is irradiated onto the foreign matter.

[0007] 1 is a block diagram showing a configuration of a laser processing machine according to an embodiment of the present disclosure. FIG.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present disclosure will now be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing the configuration of a laser processing machine 1 according to an embodiment of the present disclosure.

[0009] The laser processing machine 1 processes a workpiece by irradiating it with a laser. The laser processing machine 1 includes a laser head 10, a gap sensor 20, a gas nozzle 30, a drive mechanism 40, and a control device 50.

[0010] The laser head 10 emits a laser beam. The laser beam can be generated by a laser oscillator 11 and supplied to the laser head 10 through an optical system such as an optical fiber.

[0011] The gap sensor 20 is held integrally with the laser head 10 and measures the distance from itself to the workpiece. The measurement value of this gap sensor 20 can be converted into the distance between the laser head 10 and the workpiece. The measurement position by the gap sensor 20 is a position close to the laser irradiation position by the laser head 10, and is a position where the material of the workpiece will not melt due to the laser being irradiated during measurement.

[0012] The gas nozzle 30 injects gas onto the workpiece. The gas nozzle 30 in the present disclosure injects gas to blow away foreign matter, but may also be used as a nozzle that injects assist gas used in laser processing. In other words, the gas injected by the gas nozzle 30 may be assist gas. The gas nozzle 30 may be held integrally with the laser head 10.

[0013] The drive mechanism 40 moves the laser head 10 and the workpiece relative to each other. That is, the drive mechanism 40 may be configured to move either the laser head 10 or the workpiece, or may be configured to move both the laser head 10 and the workpiece. The drive mechanism 40 may be configured to have four or more drive axes so as to enable two-dimensional relative movement in a planar direction along the workpiece surface to determine the laser irradiation position on the workpiece surface, relative movement in a height direction perpendicular to the workpiece surface to adjust the depth position of the laser focus in the workpiece, and rotational movement to determine the angular position of the gap sensor 20 relative to the laser head 10.

[0014] The control device 50 controls the gas nozzle 30 and the drive mechanism 40. The control device 50 may be realized by one or more computers that include, for example, a memory, a processor, an input / output interface, and the like, and that execute appropriate control programs. The control device 50 includes a program control unit 51, a distance adjustment unit 52, a foreign matter determination unit 53, a removal control unit 54, and a confirmation control unit 55. Note that these components categorize the functions of the control device 50, and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0015] The program control unit 51 generates command values ​​to operate each drive axis of the drive mechanism 40 so that the laser head 10 and the workpiece move relative to each other in accordance with the machining program. More specifically, the program control unit 51 generates command values ​​to operate the drive mechanism 40 so that the gap sensor 20 is positioned ahead of the laser head 10 in the direction of movement relative to the workpiece. In other words, the planar position at which the laser is irradiated is the position at which the gap sensor 20 most recently measured the distance to the workpiece. The configuration of the program control unit 51 can be similar to that of a control device for a conventional laser processing machine.

[0016] The distance adjustment unit 52 corrects the command value generated by the program control unit 51 so as to maintain the measurement value of the gap sensor 20 at a predetermined value during control by the program control unit 51, that is, so as to maintain the depth position of the laser focus in the workpiece at a preset position optimal for processing. The configuration of the distance adjustment unit 52 can be the same as that in a control device of a conventional laser processing machine.

[0017] The foreign matter determination unit 53 determines whether or not a foreign matter is attached to the surface of the workpiece based on the measurement value of the gap sensor 20. Specifically, the foreign matter determination unit 53 can be configured to determine that a foreign matter is attached to the surface of the workpiece when the rate of decrease in the distance to the workpiece measured by the gap sensor 20 exceeds a preset threshold value.

[0018] When the foreign matter determination unit 53 determines that foreign matter is attached, the removal control unit 54 interrupts control by the program control unit 51 and generates a command value to operate the drive mechanism 40 so that the laser is irradiated onto the foreign matter. In other words, the removal control unit 54 specifies the planar position and height position of the laser head 10 relative to the workpiece so that the laser focal point is inside the foreign matter attached to the surface of the workpiece. In this way, the foreign matter attached to the workpiece is heated and removed from the surface of the workpiece.

[0019] The removal control unit 54 may set the height position of the laser head 10 according to the surface height of the workpiece estimated from the measurement value of the gap sensor 20 before the foreign matter determination unit 53 determined that a foreign matter is present, or may set the height position of the laser head 10 according to the measurement value of the gap sensor 20 at the position where a foreign matter is present. In other words, the removal control unit 54 may maintain the height position of the laser focus at a constant height that prevents the laser from melting the workpiece material at the estimated height of the workpiece surface, or may change the height position to a constant depth position from the surface of the foreign matter calculated from the measurement value of the gap sensor 20. Furthermore, when the laser is irradiated onto the foreign matter, the output of the laser may be adjusted so as not to melt the workpiece.

[0020] If the foreign matter determination unit 53 determines that foreign matter is attached immediately after the program control unit 51 performs piercing to create a through hole in the workpiece, the removal control unit 54 may be configured to generate a command value to operate the drive mechanism 40 so that the laser is irradiated along the entire outer circumference of the through hole. If the foreign matter is spatter generated during piercing, there is a risk that the spatter will be attached widely around the created through hole. Therefore, if foreign matter is detected attached immediately after piercing, removing the spatter from the entire circumference of the through hole more reliably prevents processing defects.

[0021] The removal control unit 54 may irradiate the foreign matter with the laser and at the same time cause the gas nozzle 30 to inject gas onto the foreign matter being irradiated with the laser. This facilitates removal of the foreign matter and more reliably prevents processing defects.

[0022] After the removal control unit 54 irradiates the foreign matter with a laser, the confirmation control unit 55 generates a command value to operate the drive mechanism 40 so that the gap sensor 20 measures the distance to the workpiece at the planar position where the foreign matter was present. This makes it possible to confirm whether the foreign matter has been removed. If it is determined that the foreign matter has not been removed, the removal control unit 54 may execute control to irradiate the foreign matter with a laser again. If it is determined that the foreign matter has been removed, the control by the program control unit 51 is resumed from the position where it was interrupted.

[0023] As described above, in the laser processing machine 1 according to the present disclosure, the foreign matter determination unit 53 determines whether foreign matter is attached to the workpiece based on measurements by the gap sensor 20, and the removal control unit 54 executes the operation of irradiating the foreign matter with a laser to remove it only when necessary. Therefore, the laser processing machine 1 can remove not only spatter that may occur during piercing, but also foreign matter such as objects that have fallen from the outside. Furthermore, if there is no foreign matter, the laser processing machine 1 can perform laser processing without performing any extra operations, resulting in little delay in processing time.

[0024] The following supplementary notes are further disclosed regarding the above-described embodiments and modifications. (Supplementary Note 1) A laser processing machine (1) includes a laser head (10) that emits a laser, a gap sensor (20) that is held integrally with the laser head (10) and that measures the distance to a workpiece, a drive mechanism (40) that moves the laser head (10) and the workpiece relative to each other, and a control device (50) that controls the drive mechanism (40). The control device (50) includes a program control unit (51) that generates command values ​​for operating the drive mechanism (40) so that the laser head (10) and the workpiece move relative to each other in accordance with a processing program, and a program control unit (52) that generates command values ​​for operating the drive mechanism (40) so that the laser head (10) and the workpiece move relative to each other in accordance with a processing program. a distance adjustment unit (52) that corrects a command value generated by the program control unit (51) so as to maintain the measurement value of the gap sensor (20) at a predetermined value during control by 1), a foreign matter determination unit (53) that determines whether or not a foreign matter is attached to the surface of the workpiece based on the measurement value of the gap sensor (20), and a removal control unit (54) that, when the foreign matter determination unit (53) determines that a foreign matter is attached, interrupts control by the program control unit (51) and generates a command value to operate a drive mechanism (40) so that a laser is irradiated onto the foreign matter.

[0025] (Supplementary Note 2) In the laser processing machine (1) of Supplementary Note 1, the control device (50) may further include a confirmation control unit (55) that generates a command value for operating the drive mechanism (40) to cause the gap sensor (20) to measure the distance to the workpiece at the position where the foreign object was present, after the laser is irradiated onto the foreign object by the removal control unit (54).

[0026] (Supplementary Note 3) The laser processing machine (1) of Supplementary Note 1 or 2 may further include a gas nozzle (30) that injects gas onto the workpiece, and the removal control unit (54) may cause the gas nozzle (30) to inject gas onto the foreign matter that is irradiated with the laser.

[0027] (Supplementary Note 4) In the laser processing machine (1) of any of Supplementary Notes 1 to 3, if the foreign matter determination unit (53) determines that foreign matter is attached immediately after the program control unit (51) performs piercing to create a through hole in the workpiece, the removal control unit (54) may generate a command value to operate the drive mechanism (40) so that the laser is irradiated around the entire outer circumference of the through hole.

[0028] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the confirmation control unit is not an essential component. Furthermore, the order of each operation and the order of each process are shown as examples and are not limited to these.

[0029] REFERENCE SIGNS LIST 1 Laser processing machine 10 Laser head 20 Gap sensor 30 Gas nozzle 40 Driving mechanism 50 Control device 51 Program control unit 52 Distance adjustment unit 53 Foreign matter determination unit 54 Removal control unit 55 Verification control unit

Claims

1. A laser processing machine comprising: a laser head that emits a laser; a gap sensor that is held integrally with the laser head and measures the distance to a workpiece; a drive mechanism that moves the laser head and the workpiece relatively; and a control device that controls the drive mechanism, wherein the control device has: a program control unit that generates command values ​​to operate the drive mechanism so that the laser head and the workpiece move relatively in accordance with a processing program; a distance adjustment unit that, while controlled by the program control unit, corrects the command values ​​generated by the program control unit so as to maintain the measurement value of the gap sensor at a predetermined value; a foreign matter determination unit that determines whether or not a foreign matter is attached to the surface of the workpiece based on the measurement value of the gap sensor; and a removal control unit that, when the foreign matter determination unit determines that the foreign matter is attached, interrupts control by the program control unit and generates a command value to operate the drive mechanism so that the laser is irradiated onto the foreign matter.

2. The laser processing machine of claim 1, wherein the control device further has a confirmation control unit that generates a command value to operate the drive mechanism so that the gap sensor measures the distance to the workpiece at the position where the foreign object was present after the laser is irradiated onto the foreign object by the removal control unit.

3. A laser processing machine as described in claim 1 or 2, further comprising a gas nozzle for injecting gas onto the workpiece, wherein the removal control unit causes the gas nozzle to inject gas onto the foreign matter being irradiated with the laser.

4. A laser processing machine as described in any one of claims 1 to 3, wherein if the foreign matter determination unit determines that the foreign matter is attached immediately after the program control unit performs piercing to create a through hole in the workpiece, the removal control unit generates a command value to operate the drive mechanism so that the laser is irradiated around the entire outer circumference of the through hole.

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