JP6210456B2 - Long distance laser cutting device - Google Patents

Description

  The present invention is an improvement of a laser cutting device, and more specifically, it can cut an object at a distant position (up to several tens of meters), as well as an object with various distances from an irradiation head. The present invention relates to a long-distance laser cutting device that can automatically and efficiently adjust the focal position steplessly and that can ensure a sufficient focal length adjustment range.

  In recent years, laser cutting devices have been widely used for cutting metal materials and dismantling work on structures made of steel, concrete, or the like. When using the laser cutting device, the laser beam is focused on the object to be cut so that the irradiation energy density is maximized and the cutting groove width (kerf width) is minimized. It is common to set.

  However, in a long-distance irradiation type laser cutting apparatus that cuts a long-distance object at a position several meters or more away from the irradiation head, the focal position of the laser beam is set in a wide range according to the distance between the irradiation head and the cutting object. Although it is necessary to adjust over a range (a few meters to a few tens of meters), a laser cutting device that enables this has not been developed yet.

  Incidentally, as a conventional technique, for example, a laser cutting device has been developed that can cut from a thin plate to a thick plate using a lens having two condensing distances (see Patent Document 1). Since there are only two options for the focal length, the focal length cannot be adjusted steplessly (continuously) with respect to the cutting object placed at various positions outdoors.

  Further, as a conventional technique, the distance between the irradiation head and the object to be cut is measured by a laser distance meter or the like, and further, the optical system (movable lens, beam expander, etc.) in the irradiation head is placed on the optical path based on this measurement data. Also known is a laser cutting device in which the focal length can be adjusted steplessly by moving it back and forth (see, for example, Patent Documents 2 to 4).

  However, regarding the techniques according to the above-mentioned documents 2 to 4, it is assumed that the cutting object is fixed on the processing table, and the cutting process is performed by irradiating the laser beam from the irradiation head arranged close to the processing table. Therefore, the focus position adjustment range is limited to a short distance (a range of about 100 mm in References 2 and 3 and a range of about 300 to 600 mm in Reference 4) in any technique.

  On the other hand, a laser cutting apparatus for long-distance irradiation of 40 m or less has been conventionally known (see Patent Document 5). With regard to this apparatus, means for controlling the position of the optical system in the irradiation head is known. Therefore, it has been necessary to adjust the focal length by changing the position of the irradiation head itself by moving the arm that supports the irradiation head and the traveling means under the apparatus. Therefore, the adjustment range of the focal length is narrow and the adjustment cannot be performed efficiently.

JP 2006-192504 A JP 2008-215829 A JP 2010-82663 A JP2013-226590A JP 2014-91133 A

  Therefore, the present invention has been made in view of the above-described problems, and the object of the present invention is not only to cut an object at a distant position but also various distances from the irradiation head. It is an object of the present invention to provide a long-distance laser cutting apparatus that can automatically and continuously adjust the focal position of a target object in a stepless manner and that can sufficiently secure a focal length adjustment range.

  Means employed by the present inventor for solving the above-described problems will be described with reference to the accompanying drawings.

That is, the present invention is a fiber laser light source 1 that is used as a light source of the processing laser light L ₁ and has a light guide optical fiber 11 on the output side; And the front and rear fixed lenses 21a and 21a disposed on the optical axis as the condensing optical system 21, and the movable lens 21b disposed therebetween, and the movable lens 21b is disposed on the optical axis. An irradiation head 2 provided with a lens drive unit 22 that can be moved stepwise in the back and forth along the head; a head rotation mechanism 3 that rotates the irradiation head 2 forward and backward in a predetermined direction and rotation angle; and the irradiation head 2 A distance measuring device 4 capable of measuring the distance between the irradiation head 2 and the object to be cut W in a fixed state; connected to the distance measuring device 4 and the lens driving unit 22 of the irradiation head 2 by wire or wirelessly; And received from the distance measuring device 4 Constitute long-distance illumination laser irradiation apparatus from the control device 6 for controlling the lens driving unit 22 based on the distance data,
Further, the position control of the movable lens 21b based on the distance data enables the focal position F of the processing laser light L ₁ emitted from the irradiation head 2 to be automatically adjusted at a position 1 m or more away from the irradiation head 2. There are features.

  In the present invention, a telescope 5 having a zoom function is attached to the irradiation head 2 and connected to the control device 6 in a wired or wireless manner, and based on the distance data obtained from the distance measuring device 4. The zoom magnification of 5 can also be configured to be automatically adjustable by the control device 6.

  In that case, the control device 6 is provided with a focal position correction means capable of correcting and controlling the lens driving unit 22 manually or automatically according to the cutting state of the cutting object W monitored by the telescope 5. It is preferable to keep it.

Further, it is desirable that the focal position F of the processing laser beam L ₁ emitted from the irradiation head 2 is automatically adjusted at least within a range of 1 to 30 m from the irradiation head 2. .

  In the present invention, in the laser cutting device, a condensing optical system having a movable lens is provided in the irradiation head, and the movable lens of the condensing optical system is provided between the irradiation head obtained from the distance measuring device and the cutting object. By providing a lens drive unit and a control device for position control based on distance data, laser cutting can be easily performed by adjusting the focal point position even for an object at a distance of 1 m or more from the irradiation head. It becomes possible.

  Moreover, in the present invention, the adjustment of the focal length of the laser beam is automatically performed by the control device without moving the position of the irradiation head, so that even when the focal position is largely changed, it is efficiently shortened. You can complete the adjustment in time. Further, the adjustment of the focal length can be performed steplessly over a wide range of several meters to several tens of meters by controlling the position of the movable lens, so that a sufficient cutting area can be secured.

  Therefore, according to the present invention, not only can the cutting work be safely performed at a distance from the object to be cut, but also the cutting work by remote operation can be facilitated, and the cutting work of the thick steel plate and the large structure Since a long-distance laser cutting device that can be used for a wide range of applications such as dismantling can be provided, the practical utility value of the present invention is very high.

It is the schematic showing the laser cutting device in Example 1 of this invention.

“Example 1”
A first embodiment of the present invention will be described with reference to FIG . In the figure, what is indicated by reference numeral 1 is a fiber laser light source, and what is indicated by reference numeral 2 is an irradiation head. Also, what is indicated by reference numeral 3 is a head rotating mechanism, and what is indicated by reference numeral 4 is a distance measuring device. What is indicated by reference numeral 5 is a telescope, and what is indicated by reference numeral 6 is a control device.

[Configuration of laser cutting device]
First, in the laser cutting apparatus A of the present embodiment, a fiber laser light source 1 having a light guide optical fiber 11 on the output side is used as a light source of the processing laser light L ₁ , and the fiber laser light source 1 and the processing laser light are used. The irradiation head 2 of the laser beam L ₁ is connected by a cable connector 11a through a light guiding optical fiber 11 (see FIG. 1).

In this embodiment, the fiber laser light source _{1 serving as} the light source of the processing laser light L ₁ uses an output of 30 kW, an oscillation method: continuous light (CW), and a wavelength: 1.07 μm. As long as the fiber laser has the performance that can be used for the laser cutting process, those having different outputs, those having a pulsed oscillation system, and those having different wavelengths can be employed.

Further, the irradiation head 2, as well as arranged one after the pair of fixed lens 21a · 21a on the optical axis as a focusing optical system 21 of the processing laser beam L _1, the movable lens 21b between the fixed lens 21a · 21a Is arranged and configured. Furthermore, the irradiation head 2 incorporates a lens driving unit 22 for adjusting the movable lens 21b to move back and forth along the optical axis in a stepless manner.

Here, the condensing optical system of the irradiation head 2 will be briefly described. First, let d be the distance between the two lenses 21b and 21a, and let f1 and f2 be their focal lengths. When the front movable lens 21b is a concave lens and the rear fixed lens 21a is a convex lens (f1 <0, f2> 0), the combined focal length f of both is expressed by the following equation.
From this formula:
In the limit of d → 0,
It becomes. Also,
Then, f = ∞. That is, it can be changed to f = f0 to ∞ within the range of d = 0 to d∞. For example, if f1 = −0.4 m and f2 = 0.6 m, then d∞ = 1 m and f0 = 0.24 m. By changing d from 0 to 1 m, the focal length f can be varied from several tens of centimeters to infinity. You can see that. Further, the processing laser beam L _{1 is made} into a parallel light beam by the front fixed lens 21a, and the combined focal length is made variable by the movable lens 21b and the rear fixed lens 21a, so that the object to be cut over a wide distance range. The focal length F can be adjusted to W.

On the other hand, a head rotation mechanism 3 that rotates the irradiation head 2 forward and backward in a predetermined direction and rotation angle is provided below the irradiation head 2. Thereby, the processing laser beam L ₁ can be scanned linearly on the cutting object W. In this embodiment, the rotation angle and rotation speed of the head rotation mechanism 3 can be adjusted according to the cutting state.

  Furthermore, a distance measuring device 4 is fixed to the irradiation head 2, and the distance between the irradiation head 2 and the cutting object W can be measured by the fixed distance measuring device 4. In this embodiment, a laser distance meter (Tajima D510) is used as the distance measuring device 4, but other measuring devices can be used as long as the measurement results have a predetermined accuracy.

In this embodiment, the distance measuring device 4 and the lens driving unit 22 of the irradiation head 2 are connected to the control device 6 by wire, and the lens driving unit 22 (movable lens 21b) is based on the distance data received from the distance measuring device 4. Position). As a result, the focal length K is automatically adjusted so that the focal position F of the processing laser beam L ₁ matches the position of the cutting object W.

Incidentally, adjusted for the position control of the movable lens 21b by the lens driving unit 22b, the focal position F of the processing laser beam L ₁ is at a position away 1m or more from the irradiation head 2 (range focal length K is more than 1m) Although so as to be, to to include at least 1~30m the range between the shortest focal length K _S and the longest focal length K _L is desirable.

Furthermore, in this embodiment, a telescope 5 having a zoom function is attached to the irradiation head 2, and video data obtained from the telescope 5 is transmitted to a remote monitor located away from the laser cutting device A. By doing so, the beam diameter of the processing laser beam L _{1 on} the cutting target W and the cutting status of the cutting target W can be monitored.

  In the present embodiment, the telescope 5 is wired to the control device 6 so that the zoom magnification of the telescope 5 is automatically adjusted by the control device 6 based on the distance data obtained from the distance measuring device 4. It is composed. Thereby, even when the position of the cutting target W is far from the irradiation head 2, the cutting state can be monitored firmly.

  Further, in the present embodiment, the focus position correction capable of correcting and controlling the lens driving unit 22 by manual input in accordance with the cutting state of the cutting object W monitored by the telescope 5 (focal position shift due to thermal influence, etc.). Means are provided in the control device 6. Thereby, the position of the movable lens 21b can be finely adjusted so that the focal position F and the focal distance K are optimized.

[How to use laser cutting equipment]
Next, how to use the laser cutting apparatus A will be described below. First, before performing the cutting process, the measuring laser beam L2 is emitted from the distance measuring device 4, and the distance between the cutting object W and the irradiation head 2 is calculated. Then, the calculated distance data is transmitted to the control device 6, and the lens driving unit 22 is controlled to set the position of the movable lens 21b so that the focal position F is at the position of the cutting object W.

Then, after the above preparation is completed, the processing laser beam L ₁ is emitted toward the cutting object W. At this time, the light output from the fiber laser light source 1 is guided to the cable connector 11a through the light guide optical fiber 11, and passes through the condensing optical system composed of the fixed lenses 21a and 21a and the movable lens 21b. Is emitted from the lens window 23 and irradiated to the cutting object W.

The irradiation head 2 is rotated forward and backward at a predetermined direction and rotation angle by the head rotating mechanism 3 simultaneously with the emission of the processing laser light L ₁ . Thereby, the irradiated part of the cutting object W scanned with the processing laser beam L ₁ is melted and cut. Note that the direction and rotation angle when the irradiation head 2 is rotated by the head rotating mechanism 3 are set in advance before laser irradiation.

In the cutting process, the video data transmitted from the telescope 5 is output to a remote monitor to monitor the cutting status, change in beam diameter, and the like. Then, the focal point is corrected by controlling the position of the movable lens using the correcting means of the control device 6 as necessary, such as a shift of the focal position F due to the thermal influence of the optical system or a large thickness of the object W to be cut. Feedback to position control.

Here, a numerical basis for cutting the object to be cut away by the processing laser beam L ₁ will be briefly described. First, a beam spot diameter d (m) at a focal position when a laser having a beam diameter D (m) is condensed by a lens having a focal length f (m) is obtained by the following equation.
Here, λ is a wavelength, and M2 is a parameter indicating quality. Since BPP = 10mm · mrad from actual data, M2 = 30 is obtained. When λ = 1.07 μm and D = 0.1 m, considering the spread at the focal point 30 m ahead, f = 30 (m), and substituting these, d = 0.011 m. Therefore, the beam area at the focal point is S = 1 cm ² . If a 30 kW laser is irradiated without loss, the laser energy density at the focal point is P = 30 kW / 1 cm ² = 30 kW / cm ² . And it is said that the condition that the steel material melts by laser irradiation is 6-10 kW / cm2, and the above result is well above that, so even if some optical loss is taken into consideration, it is considered possible to melt and cut the steel material sufficiently. It is done. Further, at a short distance (f <30 m), the beam diameter becomes smaller, so that cutting becomes easier.

  The present invention is generally configured as described above. However, the present invention is not limited to the illustrated embodiment, and various modifications are possible within the scope of the claims. For example, As for the correction means of the control device 6, not only a manual input method but also a method of automatically performing correction control based on video data obtained from the telescope 5 can be adopted.

  Further, regarding the connection method between the control device 6 and the lens driving unit 22 of the irradiation head 2, the distance measuring device 4, and the telescope 5, it is possible to adopt wireless connection instead of wired connection. As for the condensing optical system of the irradiation head 2, the front and rear fixed lenses 21 a and 21 a and the movable lens 21 b can also be constituted by a plurality of lens groups.

  Moreover, an elevation angle adjusting mechanism for adjusting the vertical direction of the irradiation head 2 can be provided, or a vertical rotating mechanism can be provided for the head rotating mechanism 3. Furthermore, in order to remotely control the position of the irradiation head 2, a traveling device can be provided and any of the above belongs to the technical scope of the present invention.

  Recently, the demand for laser cutting devices is increasing not only in the metal processing field but also in applications such as decommissioning of decommissioning furnaces. Under such circumstances, the long-distance laser irradiation apparatus of the present invention is a useful technique that can safely and efficiently cut thick concrete and steel materials constituting a large structure from a remote location. The above utility value is very high.

1 Fiber laser light source
11 Optical fiber for light guide
11a Cable connector 2 Irradiation head
21 Condensing optics
21a Fixed lens
21b Movable lens
22 Lens drive
23 Laser window 3 Head rotation mechanism 4 Distance measuring device 5 Telescope 6 Control device A Laser cutting device W Cutting object L ₁ Laser beam for processing L ₂ Laser beam for measurement F Focus K Focal length

Claims (4)

A fiber laser light source (1) used as a light source for the processing laser light (L ₁ ) and having a light guide optical fiber (11) on the output side; and a light guide light for the fiber laser light source (1) The front and rear fixed lenses (21a) and (21a) connected via the fiber (11) and disposed on the optical axis as the condensing optical system (21), and the movable lens (21b) disposed therebetween And an irradiation head (2) provided with a lens driving section (22) capable of steplessly moving the movable lens (21b) back and forth along the optical axis; A head rotation mechanism (3) that rotates forward and backward in the direction and rotation angle; and a distance in which the distance between the irradiation head (2) and the cutting object (W) can be measured while being fixed to the irradiation head (2) A distance measuring device connected to the distance measuring device (4) and the lens driving unit (22) of the irradiation head (2) by wire or wirelessly; And a control device (6) for controlling the lens driving unit (22) based on the distance data received from the device (4).
Further, by the position control of the movable lens (21b) based on the distance data, the focal position (F) of the processing laser beam (L ₁ ) emitted from the irradiation head (2) is separated from the irradiation head (2) by 1 m or more. Long-distance laser cutting device characterized by being automatically adjusted at different positions.   A telescope (5) having a zoom function is attached to the irradiation head (2), and is connected to the control device (6) by wire or wirelessly. The telescope is also based on the distance data obtained from the distance measuring device (4). The long-distance laser cutting device according to claim 1, wherein the zoom magnification of the scope (5) is automatically adjusted by the control device (6).   The control device (6) has a focal position correction means capable of correcting and controlling the lens drive unit (22) manually or automatically according to the cutting state of the cutting object (W) monitored by the telescope (5). The long-distance laser cutting device according to claim 2, further comprising: The focal position (F) of the processing laser beam (L ₁ ) emitted from the irradiation head (2) is automatically adjusted at least within a range of 1 to 30 m from the irradiation head (2). The long-distance laser cutting device according to any one of claims 1 to 3.