JP2017164773A - Safety device for laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety device for a laser beam machine, the safety device surely protecting a worker from exposure to laser and allowing for life prolongation of a laser oscillator without deteriorating productivity.SOLUTION: The safety device for a laser beam machine comprises: a door switch 106a which detects an open/closed state of a worker door for opening/closing an opening formed in a cover surrounding an optical head 10 and a table; a laser output part 41 which is arranged in a laser oscillator 40, and oscillates a laser beam to transmit the laser beam at a set output level to the optical head 10; and a control part 45 which reduces light source current to an excitation light source provided in the laser output part 41 to zero or reduces an output of the laser beam transmitted by the laser output part 41 to fall within a predetermined safe level while a power supply 46 of the laser oscillator 40 remains on when the door switch 106a detects an open state of the worker door.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a safety device for a laser processing machine, such as a laser processing machine, a water jet laser processing machine, a laser hardening machine, or a laser welding machine, which processes a workpiece by irradiating a laser beam.

  In particular, a laser processing machine for metal processing uses a powerful laser beam, and is usually classified as a class 4 apparatus defined in Japanese Industrial Standard JIS C 6802. For this reason, the laser processing machine has a cover that covers a table on which a workpiece is placed and an optical head that emits laser light so that harmful laser light is shielded. The cover is provided with an opening for taking in and out the workpiece and an operator door for opening and closing the workpiece. In general, a shutter for mechanically blocking the optical path of the laser beam is provided in conjunction with the opening of the operator door. It has been. When the operator opens the operator door for taking out the workpiece, the optical path of the laser beam is blocked by the shutter, so that the emission of the laser beam from the optical head is stopped and laser exposure does not occur. Yes.

  Normally, when a workpiece is sequentially processed by a laser processing machine, the laser oscillator of the laser processing machine is maintained in an operating state in the same manner as during processing when the workpiece is detached. This is because when the laser oscillator is turned off, the excitation light source is turned off and the chiller is also stopped. Therefore, it takes a relatively long time to return the laser beam output to the specified value when it is restarted. Because. In addition, if the laser oscillator is suddenly stopped, the power charged in the laser oscillator is forcibly released and may flow to the control board and be damaged. For this reason, the above-described shutter has been conventionally used as an effective means for blocking the emission of laser light from the optical head without stopping the operation of the laser oscillator.

  Patent Document 1 discloses a laser processing machine including a semiconductor laser device having a shutter that opens and closes an optical path of laser light. For safety, Patent Document 2 discloses a laser processing head having a shutter that mechanically blocks an optical path of laser light.

JP 2004-130336 A JP 2004-25216 A

  The conventional laser beam machine has a potential problem that an exposure accident occurs when the worker opens the worker door without noticing that the shutter has failed. In addition, the conventional laser processing machine continues to emit laser light in the same way as during processing even when the laser oscillator is not processing, such as when a workpiece is attached / detached. In the case of a laser, for example, the deterioration of the YAG rod is accelerated, and the failure rate of these components increases. In particular, there is a concern that the reliability of the operation of the shutter may be reduced due to a temperature increase due to laser light irradiation.

  The present invention has been made in view of the above circumstances, and is a safety device for a laser processing machine that reliably protects an operator from laser exposure and reduces the lifetime of a laser oscillator without reducing productivity. The purpose is to provide.

  In order to achieve the above-described object, according to the present invention, a laser oscillator, an optical head that irradiates the workpiece with laser light supplied from the laser oscillator, a table on which the workpiece is placed, an optical head and a table are provided. In a safety device of a laser processing machine, comprising a cover that surrounds and forms a processing chamber and shields laser light, a door switch that detects an open / closed state of an operator door that opens and closes an opening formed in the cover; A laser output unit disposed in the laser oscillator, which oscillates laser light and sends laser light of a set output level to the optical head; and a door switch opens the worker door. When the state is detected, the laser oscillator power is turned on and the current supplied to the laser output unit is set to 0 or the output of the laser beam transmitted by the laser output unit is predicted. Safety device for a laser processing machine comprising a control unit which is reduced to a value which falls within a safe level defined, is provided.

  According to the present invention, when the open state of the worker door is detected, the output of the laser beam is reduced to a safe level, so that the operator is prevented from being exposed to the laser while the laser oscillator is turned off. Therefore, when the machining is resumed, the output of the laser beam can be returned to the output level set for machining in a relatively short time. As a result, according to the present invention, it is possible to ensure the safety of the operator without reducing productivity. Further, even when the laser output unit is in operation, a time zone in which the output of the laser beam is reduced occurs, so that it is possible to realize a long life of the laser output unit.

It is a perspective view which shows an example of the laser processing machine to which this invention is applied. It is typical sectional drawing of the optical head of the said laser beam machine. It is a block diagram which shows the component of the safety device of the laser beam machine by embodiment, and the component of the laser beam machine related to it. It is a figure which shows typically the relationship between the light source current with respect to the excitation light source with which the laser output part of the said safety device is provided, and the output of the laser beam sent from a laser output part. It is a flowchart which shows the flow until laser exposure is prevented by the said safety device.

Hereinafter, a safety device for a laser beam machine according to an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of a water jet laser processing machine (hereinafter referred to as “laser processing machine”) including a safety device for a laser processing machine according to the present invention as a component. The laser processing machine 100 in FIG. 1 is suitable for metal drilling and cutting. However, it can be easily understood from the following description that the present invention can be applied to laser processing machines for various uses such as quenching of metals, welding, drilling and cutting of resin materials, and marking. It will be.

  Referring to FIG. 1, a laser processing machine 100 is provided with a table 108 for mounting a work, and a linear movement relative to the table 108 in the three orthogonal directions of the X, Y, and Z axes. The optical head 10 and a laser oscillator 40 (not shown in FIG. 1) are provided. The laser processing machine 100 also includes a rectangular parallelepiped cover 102 that surrounds the optical head 10 and the table 108 to form a processing chamber. An opening 104 is formed on the front surface of the cover 102 so that an operator can access the table 108 and the optical head 10. The cover 102 also has an operator door 106 that can slide in the left-right direction (X-axis direction) for opening and closing the opening 104. The worker door 106 includes a door switch 106a for detecting the open / closed state.

  An operation panel 110 for the laser processing machine 100 is attached to the front side wall of the cover 102. The operation panel 110 has a display 112 and various operation buttons 114 for displaying parameters indicating the state and operation of the laser processing machine 100, icons for teaching an operation method for an operator, and the like. The display 112 can be a touch panel that allows various operations to the laser processing machine 100 when an operator touches an icon with a finger. The operation panel 110 has a built-in control device, and controls the laser processing machine 100 according to an operator's input and a program stored in the control device. The operation panel 110 can be set by inputting the output of laser light used for processing. Note that the control device is not built in the control panel 110 but may be stored in another place of the machine.

  An optical head 10 shown as an example in FIG. 2 includes a laser irradiation head 16 which is disposed in a housing 12 and receives laser light from a laser oscillator 40 via an optical fiber cord 40a and irradiates the collimation lens 18. doing. The laser light from the laser irradiation head 16 is converted into parallel rays by the collimation lens 18, reflected by the first mirror 20 toward the second mirror 22, and directed toward the focus lens 24 by the second mirror 22. Reflected. The laser light focused by the focus lens 24 is irradiated through the nozzle head 26 to the workpiece W that is usually placed on the table 108 outside the housing 12. At this time, the optical axis of the laser beam irradiated by the optical head 10 is substantially parallel to the Z axis. The optical head 10 also has motors 20a and 22a as mirror orientation changing means for adjusting the direction of laser light emitted from the optical head 10. Furthermore, the optical head 10 also includes a camera 32 that monitors the positional relationship between the laser light emitted from the nozzle 26b and the nozzle 26b by forming the second mirror 22 from a dielectric multilayer film.

  The optical head 10 illustrated in FIG. 2 is of a type in which the laser light emitted from the nozzle 26 b is surrounded by a water column 34 ejected from the same nozzle 26 b and travels while being totally reflected by the inner wall of the water column 34. It is. Therefore, the ultrapure water supply device 30 is connected to the nozzle head 26 via the conduit 28.

  Next, the laser oscillator 40 of the laser processing machine 100 illustrated in FIG. 3 will be described below. 3 includes a laser output unit 41, a chiller 42, a shutter 43 that blocks and opens an optical path of laser light from the laser output unit 41 to the optical head 10, an output meter 44, and a control unit 45. The power supply unit 46 and an optical fiber cord 40a (not shown in FIG. 3) for guiding laser light to the optical head 10 are provided. The power supply unit 46 supplies power to the laser output unit 41 and the chiller 42 via the control unit 45.

  The laser output unit 41 in FIG. 3 is configured as an Nd: YAG solid-state laser resonator. Therefore, although not shown in the figure, an Nd: YAG rod, an excitation light source, a collector, a total reflection mirror, and an output mirror are included therein. Etc.

  Since the calorific values from the laser output unit 41 and the output meter 44 are considerably large, a refrigerant pipe from the chiller 42 is connected to the laser output unit 41 and the output meter 44 in order to cool them. While the laser oscillator 40 is in an energized state, the chiller 42 operates so as to supply a constant amount of refrigerant to the laser output unit 41 and the output meter 44 regardless of whether processing is performed or not.

  By the way, the safety device for a laser beam machine according to the embodiment of the present invention includes a door switch 106 a provided on the worker door 106 of the cover 102, a laser output unit 41, a control unit 45, and a shutter 43. Contains.

  Laser light emitted from the laser output unit 41 is focused by a fiber incident coupling lens (not shown) disposed in front of an incident end (not shown) of the optical fiber cord 40a and introduced into the optical fiber cord 40a. Is done. The shutter 43 is disposed in the optical path of the laser light between the emission end of the laser output unit 41 and the fiber incidence coupling lens. The shutter 43 can take a blocking position for blocking the optical path and an open position for opening the optical path. In FIG. 3, the blocking position is indicated by a solid line, and the open position is indicated by an imaginary line. The shutter 43 is a plate having a pivot, and is a type that is rotated by a motor 47 about the pivot. The shutter 43 includes a reflecting surface that reflects the laser beam received from the laser output unit 41 toward the output meter 44 when the shutter 43 is in the blocking position.

  The control unit 45 includes a shutter control unit 48 and an output control unit 49. The shutter control unit 48 controls the shutter driving motor 47 based on a signal from a door switch 106 a provided on the worker door 106 of the cover 102. More specifically, when the door switch 106a detects the open state of the worker door 106, the shutter control unit 48 moves the shutter 43 to the blocking position by the motor 47 and holds the position, and the door switch 106a moves to the worker door. When a closed state of 106 is detected, the motor 47 is configured to move the shutter 43 to the open position and hold the position.

  The output control unit 49 controls the current (hereinafter referred to as “light source current”) supplied to the excitation light source of the laser output unit 41, thereby changing the output of the laser light emitted from the laser output unit 41 from 0 to a specified maximum output. It is comprised so that it may control between. The output control unit 49 is also configured to monitor the output of the laser light reflected to the output meter 44 by the shutter 43 disposed at the cutoff position when the laser oscillator 40 is started and started. When the output of the laser light reaches a specified output, the shutter control unit 48 moves the shutter 43 to the open position by the motor 47 and holds it at that position.

  Here, referring to FIG. 4 schematically showing the relationship between the current supplied to the laser output unit 41 in this embodiment, that is, the light source current and the output of the laser beam (hereinafter sometimes referred to as “laser beam output”). The laser light output increases as the light source current increases as a whole, although the light source current has a temporary drop in the vicinity of 20 A, and reaches a maximum value at 30 A. FIG. 4 also shows that the laser beam output is zero until the light source current is about 8A. Thus, it is noted that there is a region of light source current that does not produce laser light output. In the example of FIG. 4, the laser light output is at a safe level equivalent to class 1 when the light source current is about 10 A or less, and at a dangerous level when it exceeds about 10 A.

  When the door switch 106a detects that the operator door 106 of the cover 102 is in the open state, the output control unit 49 of the control unit 45 in the present embodiment sets the value of the light source current to 0 or the laser beam output in advance. To a value that falls within a safe level. However, at this time, it is important that the power supply unit 46 of the laser oscillator 40 is kept on, that is, the power supply unit is not turned off. In the present embodiment, the value of the light source current to be reduced may be set to 5A, for example. This is because the laser light output when the light source current is 5 A is 0 and is at a safe level. In the present embodiment, the value of the light source current to be reduced may be set to 9A, for example. This is because the laser light output when the light source current is 9 A is not 0, but is at a safe level as shown in FIG. Of course, the value of the light source current may be set to zero.

  Thus, in this embodiment, when the door switch 106a detects that the operator door 106 of the cover 102 is in the open state, the output control unit 49 of the control unit 45 does not reduce the light source current to zero. Reduce the light output to a safe level. By doing so, the safety for the worker is ensured, but the time until the laser light output returns to a level suitable for processing is compared when the light source current is set to 0 when processing is resumed. Then, it becomes possible to shorten considerably. In addition, since a time zone in which the laser beam output is reduced occurs, the life of the laser output unit 41 can be extended as compared with the conventional laser output unit that always transmits a high output laser beam. Is possible. Further, when the shutter 43 is in the shut-off position, the output of the laser light irradiated to the shutter 43 and the output meter 44 is lowered, so that the temperature rise of the shutter 43 and the output meter 44 is suppressed, and their life is extended. Can also be realized.

  In the present embodiment, the chiller 42 is always operating while the laser oscillator 40 is in the energized state. Therefore, unless the power supply unit 46 of the laser oscillator 40 is turned off, it is not necessary to consider the time required to restart the chiller 42 when resuming the machining.

  In addition, since the safety device of the laser beam machine according to the present embodiment also includes the shutter 43, when the operator door 106 of the cover 102 is opened, not only the laser light output is reduced to a safe level, The optical path of the laser beam is also blocked. Therefore, double safety against laser exposure is ensured.

  FIG. 5 is a flowchart schematically showing a flow until laser exposure is prevented by the safety device for a laser beam machine according to the embodiment of the present invention. Explaining with reference to this figure, after the work W is set on the table 108 and the operator door 106 of the cover 102 is closed, the laser processing machine 100 is turned on (S10), and the laser oscillator 40 is activated in advance. Processing is started with the set laser beam output (S20). When the processing is interrupted and the processing state of the workpiece W is confirmed, or when the processing is completed and the operator door 106 of the cover 102 is opened for replacement of the workpiece W (S30), the light source current is reduced and the laser is reduced. Not only does the light output drop to a safe level (S40), but the shutter 43 blocks the optical path almost simultaneously (S50). As a result, the operator is not exposed to the laser (S60). On the other hand, if the worker door 106 remains closed, the worker is naturally not exposed to the laser. In step S40, the light source current is reduced but not reduced to 0 so that the laser light output is reduced to a safe level.

  Although not shown in FIG. 5, when the confirmation of the machining state of the workpiece and the attachment / detachment of the workpiece are completed, the opened operator door 106 is closed and the start button of the operation panel 110 is pressed, the shutter 43 is opened. The laser beam output is immediately restored to a preset laser beam output, and laser processing is resumed.

  In the above-described embodiment, when the worker door 106 is opened, not only the laser light output is reduced to a safe level but also the shutter 43 blocks the optical path, thereby ensuring double safety against laser exposure. It was done. However, in the present invention, an embodiment without a shutter is also possible as a component of the safety device of the laser processing machine.

  Although the laser output unit 41 in the above-described embodiment is configured as an Nd: YAG solid-state laser resonator, the present invention is not limited thereto, and in the present invention, various types of solid-state lasers can be used as the laser output unit. A gas laser such as a carbon dioxide laser can also be used.

DESCRIPTION OF SYMBOLS 10 Optical head 40 Laser oscillator 41 Laser output part 42 Chiller 43 Shutter 44 Output meter 100 Laser processing machine 102 Cover 106 Worker door 106a Door switch 108 Table 110 Operation panel

In order to achieve the above-described object, according to the present invention, a laser oscillator, an optical head that irradiates a workpiece with laser light supplied from the laser oscillator, a table on which the workpiece is placed, an optical head and a table are surrounded. In the safety device of the laser processing machine that includes a cover that partitions the processing chamber and shields the laser beam, a door switch that detects an open / closed state of an operator door that opens and closes an opening formed in the cover; A laser output unit disposed in the laser oscillator, which oscillates laser light and sends laser light of a set output level to the optical head, and is sent from the laser output unit to the optical head A shutter disposed in the optical path of the laser beam, which can take an open position for opening the optical path and a blocking position for blocking the optical path, and is in the blocking position A shutter having a reflective surface for reflecting over The light, when the shutter is taking a position for blocking the optical path, and an output meter for detecting the output level of the laser beam reflected by the reflecting surface of the shutter, a door switch operator When the open state of the door is detected, the current supplied to the laser output unit is reduced to 0 or the value of the laser beam output from the laser output unit is reduced to a value that falls within a predetermined safe level while the laser oscillator is turned on. And a control unit that moves the shutter to a position that blocks the optical path and monitors the output level of the laser light of the output meter , and a safety device for a laser processing machine.

Claims (4)

A laser oscillator; an optical head that irradiates the workpiece with laser light supplied from the laser oscillator; a table on which the workpiece is placed; and the optical head and the table surrounding the table to form a processing chamber and to emit laser light. In a safety device for a laser processing machine comprising a cover for shielding,
A door switch for detecting an open / closed state of an operator door that opens and closes an opening formed in the cover;
A laser output unit disposed in the laser oscillator, wherein the laser output unit oscillates a laser beam and sends a laser beam having a set output level to the optical head;
When the door switch detects the open state of the operator door, the current supplied to the laser output unit is 0 while the laser oscillator is turned on, or the output of the laser beam sent by the laser output unit is A safety device for a laser processing machine, comprising: a control unit that reduces the value to a value that falls within a predetermined safe level.   The safety device for a laser processing machine according to claim 1, wherein the control unit is disposed in the laser oscillator. A shutter disposed in an optical path of a laser beam sent from the laser output unit to the optical head, wherein the shutter can take an open position for opening the optical path and a blocking position for blocking the optical path; Has
3. The safety device for a laser processing machine according to claim 1, wherein when the door switch detects an open state of the worker door, the control unit moves and holds the shutter to a blocking position.   When the laser oscillator is powered on, a chiller that cools the laser output unit is always in operation, and the control unit further sets the setting when the door switch detects the closed state of the operator door. The safety device for a laser processing machine according to any one of claims 1 to 3, wherein a state in which the laser beam having the output level is transmitted from the laser output unit is maintained.

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