JP2006055878A - Method for preventing re-sticking in laser beam cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing the re-sticking of a workpiece in laser beam cutting, when the workpiece is cut off by the laser beam. <P>SOLUTION: When the workpiece 1 is cut off by the laser beam, a bending force is preliminarily applied to a portion 3 to be cut-off of the workpiece 1. Then, the laser beam is irradiated on the portion 3 in such a state to cut off the workpiece 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for preventing re-adhesion during laser cutting for preventing re-adhesion of a material to be cut when the material to be cut is cut using a laser.

  Conventionally, a material to be cut such as a steel structure is sometimes cut using a laser. In general, laser cutting is performed by irradiating a laser toward a cutting portion of a material to be cut and injecting an assist gas such as nitrogen and blowing the material to be cut (melted dross) once melted from the cutting portion. (See Patent Document 1).

  By the way, there is a case where laser cutting must be performed in a state where a back side member such as a plate material is provided on the back side of the material to be cut. In such a case, the effect of the assist gas is weakened by the back member, so that the molten dross does not blow out sufficiently, and the material to be cut may be re-adhered due to the remaining molten dross. Conventionally, when re-adhesion occurs, the re-adhered part is hit manually with a hammer to separate the re-adhered part.

Japanese Patent No. 3463377

  However, such separation work of the refixed portion has the following problems.

  The work of hitting with a hammer is a heavy burden on the operator, and the separation work is performed in addition to the normal laser cutting work, resulting in an increase in work steps and deterioration in work efficiency.

  Furthermore, when the laser cutting operation is performed in an environment where it is very difficult for a person to enter (for example, a high radiation environment), it is necessary to cause the robot to perform a hammering operation. The strength that can withstand the impact force that is returned as a reaction and the control that corrects the adverse effect exerted on the positioning sensor of the robot by the impact force are required, which increases the cost of the robot and the cost of the cutting work.

  Accordingly, an object of the present invention is to solve the above-described problems and to re-adhere at the time of laser cutting that can prevent re-adhesion at the time of laser cutting of the material to be cut when cutting the material to be cut using a laser. It is to provide a prevention method.

  In order to achieve the above-mentioned object, the present invention applies a bending force to a cutting portion of the material to be cut in advance when cutting the material using a laser, and irradiates the cutting portion with the laser in that state. Cutting.

  In order to achieve the above-mentioned object, the present invention cuts the material to be cut using a laser in a state where a back side member such as a plate material is provided on the back side of the material to be cut at a distance from the material to be cut. At the time, a tapped hole is made in the vicinity of the cut portion of the material to be cut, a bolt is screwed into the tap hole, the tip of the bolt is further applied to the back side member to be further screwed, and a bending force is applied to the material to be cut. In this state, the cutting portion is irradiated with a laser and cut.

  According to the present invention, when cutting the material to be cut, a bending force is previously applied to the cutting portion of the material to be cut, and the cutting portion is irradiated with a laser in that state and cut immediately after cutting. Since the materials to be cut located on both sides of the cut portion move relative to each other, an excellent effect that re-adhesion can be prevented is exhibited.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view for explaining a method for preventing re-adhesion during laser cutting according to the present embodiment. FIG. 2 shows a front view of the material to be cut.

  In the present embodiment, the method for preventing re-adhesion at the time of laser cutting according to the present invention is applied to a laser cutting operation of a steel structure of a glass melting furnace performed when the glass melting furnace is dismantled.

  First, the schematic structure of the glass melting furnace will be described with reference to FIGS.

  The glass melting furnace 60 is mainly composed of a gantry 61 and a furnace main body 62 placed on the gantry 61, and the furnace main body 62 includes an inner casing 64 (see FIG. 11) that covers the furnace main body 62. The inner casing 64 is provided with an outer casing 65 that surrounds the side of the inner casing 64 with a space therebetween. Further, an upper heat radiating portion 68 made of a steel material is provided on the top surface of the top plate 66 of the inner casing 64. The upper heat radiating portion 68 is formed by combining a plurality of plate-like ribs 69 and 70 extending vertically upward from the upper surface of the top plate 66 of the inner casing 64 in a lattice shape in a top view.

  When disassembling the glass melting furnace 60, as shown in FIG. 1, a plate-like rib 69 constituting the upper heat radiating portion 68 was divided into a plurality of portions in the longitudinal direction by ribs 70 orthogonal to the rib 69. The part is laser-cut for each partition part and disassembled finely. In this case, since there are other ribs 69 at intervals on the back side of the ribs 69 to be cut, the ribs 69 to be cut may be fixed again as described in the section “Background Art”. . Therefore, in order to prevent re-adhesion of the rib 69, the re-adhesion prevention method at the time of laser cutting according to this embodiment is used.

  The re-adhesion preventing apparatus and method at the time of laser cutting according to the present embodiment will be described below.

  In the present embodiment, another rib 69 (hereinafter referred to as the back side member 2) is provided on the back side of the rib 69 (hereinafter referred to as the material to be cut 1) located on the rightmost side in FIG. In this state, the workpiece 1 is cut using a laser. Specifically, in the material 1 to be cut, a plurality of sections partitioned in the longitudinal direction by ribs 70 orthogonal to the material 1 to be cut are along the orthogonal ribs 70 and the top plate 66 as shown in FIG. Laser cutting is performed along the cut portion 3 (cutting line). The back side of the material 1 to be cut is the side opposite to the side irradiated with the laser, and the front side is the side irradiated with the laser. Further, a part of the material 1 to be cut (that is, a part to be separated after cutting) surrounded by the cut portion 3 and the upper edge of the material 1 to be cut is used as a cutting piece 29, and the remaining part of the material 1 to be cut is a remaining piece. 30.

  First, based on FIG. 1, FIG. 3, and FIG. 10, the re-adhesion preventing device at the time of laser cutting according to the present embodiment will be described.

  The apparatus for preventing re-adhesion at the time of laser cutting according to the present embodiment includes a laser cutting means for cutting a material to be cut 1 using a laser, and a bending force for applying a bending force in advance to a cutting portion 3 of the material to be cut 1. Means.

  As shown in FIG. 1, the laser cutting means of the present embodiment includes a laser cutting device 6 having a laser torch 8 that irradiates a laser to the cutting location 3, and a laser torch 8 and also arranges the laser torch 8 at the cutting location 3. And a robot 9 that performs the operation.

  As shown in FIG. 3B, the laser cutting device 6 of this embodiment includes a laser generator (not shown) that is installed outside the building where the glass melting furnace 60 is installed, and generates the laser. A laser torch 8 is connected to the generator via an optical fiber and a gas tube 10 and irradiates a laser and injects an assist gas. In this embodiment, a YAG laser is used as the laser.

  As shown in FIGS. 3A and 10, the robot 9 of the present embodiment is provided above a building (not shown) where the glass melting furnace 60 is installed, and is movable in the horizontal direction. (Refer to FIG. 10), a leg portion 12 whose upper end portion is coupled to the crane portion 11 and is vertically stretchable, an arm 14 coupled to the lower end portion of the leg portion 12 and having a plurality of joints, and the arm 14 And a gripping portion 15 that grips a laser torch 8, a screw tap 23, a hexagon wrench 25, and the like which will be described later. A tool such as a laser torch 8 gripped by the gripping part 15 of the robot 9 is arranged and directed at an arbitrary work position of the glass melting furnace 60 by the crane part 11, the leg part 12 and the arm 14. In the present embodiment, since the laser cutting operation is performed in a high radiation environment (that is, an environment where no human enters or is extremely difficult to enter), the robot 9 is remotely operated.

  Next, as shown in FIG. 1, the bending force applying means of the present embodiment includes a tapped hole making means for making a tapped hole 16 in the vicinity of the cutting location 3 of the workpiece 1, and a bolt 20 screwed into the tapped hole 16. , And a screwing means for screwing the bolt 20.

  The tapped hole making means of this embodiment includes a prepared hole making means for making the prepared hole 21 of the tapped hole 16 and a thread cutting means for cutting a female screw in the prepared hole 21. As shown in FIGS. 3B and 3C, in this embodiment, the pilot hole drilling means is the laser cutting device 6, and the thread cutting means is the screw tap 23. That is, in this embodiment, the laser cutting device 6 serves as both cutting means and pilot hole making means.

  As shown in FIG. 1, the bolt 20 of the present embodiment includes a bolt head 22 formed in a hexagonal shape, and a screw portion 24 in which a male screw is cut from the bolt head 22 to the tip of the bolt 20. The threaded portion 24 is formed so as to be longer than the distance between the material 1 to be cut and the back side member 2 and to have sufficient strength to apply a bending force to the cut portion 3.

  The screwing means of the present embodiment is a hexagon wrench 25 provided with a wrench head 26 that fits the bolt head 22 of the bolt 20 as shown in FIG. A magnetic force is applied to the wrench head 26 so that the bolt 20 can be joined.

  In the present embodiment, the screw tap 23 and the hexagon wrench 25 are gripped by the same robot 9 as the robot 9 that grips the laser torch 8, and are arranged at any work position in the glass melting furnace 60.

  Next, the method for preventing re-adhesion during laser cutting according to the present embodiment will be described with reference to FIGS.

  First, as shown in FIG. 4, the laser torch 8 is gripped by the gripping portion 15 of the robot 9, and the laser torch 8 forms a pilot hole 21 for the tap hole 16 in the vicinity of the cutting point 3 perpendicular to the workpiece 1. Free. In the present embodiment, only one pilot hole 21 is formed at the approximate center of the region surrounded by the cut portion 3. Next, as shown in FIG. 5, the laser torch 8 gripped by the gripping portion 15 of the robot 9 is replaced with a screw tap 23, and a female screw is cut into the prepared hole 21 perpendicularly to the workpiece 1 by the screw tap 23. Thus, the tap hole 16 is opened in the vicinity of the cutting location 3 of the workpiece 1.

  Next, as shown in FIG. 6, the screw tap 23 is replaced with a hexagon wrench 25, and the bolt 20 is screwed into the tap hole 16 with the hexagon wrench 25 until the tip of the bolt 20 abuts against the back member 2. From this state, when the bolt 20 is further screwed in by a predetermined screwing amount, the reaction force for screwing into the tap hole 16 that tries to move the workpiece 1 in the direction opposite to the screwing direction of the bolt 20, the rib 70 and the top plate The restraining force at the joint with 66 acts on the workpiece 1. These forces become a predetermined bending force corresponding to a predetermined screwing amount of the bolt 20 and are applied to the workpiece 1. Thereby, the material 1 to be cut is bent and deformed in a convex shape on the front side (see FIG. 7). In particular, a predetermined bending deformation occurs in the cut portion 3 due to the applied predetermined bending force.

  Next, in a state where this bending force is applied, the hexagon wrench 25 is changed to the laser torch 8, and the laser torch 8 starts cutting from the upper edge of the workpiece 1.

  At the time of this laser cutting, the workpieces 1 located on both sides of the cutting location 3 move relative to each other at the same time as heat is input by the laser. Specifically, as shown in FIG. 8, when the cut portion 3 is melted by the irradiated laser (that is, immediately after cutting), the remaining piece 30 side is released from the screwing reaction force and starts to be restored based on the joint portion. (The restored state is indicated by a solid line in FIG. 8). That is, the cut portion 3 of the remaining piece 30 starts to move toward the back side. On the other hand, since the cut piece 29 side is released from the restraining force, it starts to be restored based on the tap hole 16 (the restored state is indicated by a solid line in FIG. 8). That is, the cut portion 3 of the cut piece 29 moves toward the front side. That is, the bending force applied in advance acts as a shearing force that shifts the remaining piece 30 and the cutting piece 29 from each other immediately after cutting at the cutting point 3. Such relative movement of the remaining piece 30 and the cut piece 29 at the cutting point 3 is performed from immediately after cutting until the molten dross at the cutting point 3 is solidified, thereby preventing re-adhesion of the material 1 to be cut.

  Further, such laser cutting is performed along the entire circumference of the cutting location 3 to separate the cut piece 29 from the material 1 to be cut (see FIG. 9).

  As described above, the bending force applied to the cut portion 3 is for preventing re-adhesion, and the remaining piece 30 and the cut piece 29 are relatively moved at least during the period from immediately after cutting until the molten dross solidifies. Must be set to a value that can be Therefore, the screwing amount of the bolt 20 for securing such a bending force is such that the distance between the bolt 20 and the cutting location 3, the rigidity of the workpiece 1, the thickness of the workpiece 1, and the workpiece 1 is appropriately set in consideration of the solidification rate of 1.

  As described above, the method for preventing re-adhesion at the time of laser cutting according to the present embodiment applies a bending force to the cutting portion 3 of the workpiece 1 in advance when cutting the workpiece 1 and cuts the laser in that state. By irradiating the portion 3 and cutting it, the cut portion 3 is displaced, and re-adhesion at the time of laser cutting in the workpiece 1 can be prevented.

  Therefore, separation work by a hammer or the like is not necessary, the burden on the operator can be reduced, and laser cutting work can be performed more efficiently.

  Further, even when laser cutting is performed using the robot 9 in an environment where it is difficult for humans to enter, such as in a high radiation environment, it is not necessary to cause the robot 9 to perform a hammering operation, and the impact force that returns as a reaction is reduced. Since it is not necessary to add control to correct the adverse effect exerted on the positioning sensor of the robot due to the strength that can be withstood or the impact force, the cost of the robot 9 and the work cost can be kept low, and the laser cutting work can be reduced. It can be done easily.

  Further, in this embodiment, by screwing the bolt 20 into the approximate center of the region surrounded by the cutting point 3, a bending force can be evenly applied to each side of the cutting point 3, and the screwing amount of the bolt 20 is minimized. Can be limited.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  In this embodiment, although the form which screwed the volt | bolt 20 to the tap hole 16 vacated in the approximate center of the area | region enclosed by the cutting | disconnection location 3 was demonstrated, this invention is not limited to this, The position which screw | threads a bolt, and the number of volt | bolts Various things are possible.

  For example, as shown in FIG. 12, a plurality of tapped holes (shown by dotted lines in FIG. 12) are formed in a portion 42 (hereinafter referred to as a cut piece) 42 to be separated after the workpiece 41 is cut. (Not shown) may be provided at predetermined intervals, and a bolt 45 may be screwed into each of the tap holes to apply a bending force to the cut portion 44.

  In the embodiment of FIG. 12, the same effect as that of the above-described embodiment of FIG. 1 can be obtained. Further, by using a plurality of bolts 45, the bolts 45 can be arranged close to the cutting portion 44, and the material 41 to be cut is obtained. Even when it is difficult to apply a bending force with a single bolt such as when the cutting piece 42 is large or when the cutting piece 42 is large, the bending force can be reliably applied to the cut portion 44.

  Furthermore, as another embodiment in the case where the cut piece is large, a bolt may be appropriately tightened and tightened during cutting or for each predetermined cutting point (for example, each side when the cutting point is square). In this embodiment, the same effect as that of the above-described embodiment of FIG. 1 can be obtained. Further, since the cut piece is large, the bending force applied to the cut portion is reduced as the material to be cut is cut. Even in such a case, the bending force can be increased by appropriately tightening and tightening the bolts to ensure a sufficient bending force.

  In the embodiment of FIG. 1, the form in which the bolt 20 is screwed into the cut piece 29 side of the workpiece 1 has been described, but the present invention is not limited to this, and the bolt is screwed into the remaining piece 30 side of the workpiece 1. You may do it.

  In the present embodiment, the form in which the bolt 20 is screwed into the tap hole 16 in which the female thread is cut by the screw tap 23 has been described. However, the present invention is not limited to this. For example, a biting portion that can cut the female screw is formed at the tip. The drilled screw may be screwed into the pilot hole. That is, a drill screw may be used as a threading means and a bolt. In this case, it is not necessary to cut the female screw with a screw tap, and the efficiency of the laser cutting work can be further improved.

  In the embodiment of FIG. 1, the embodiment in which the tap hole 16 is formed in the workpiece 1 when actually performing the cutting operation on the upper heat radiating portion 68 has been described. However, the present invention is not limited to this. When constructing a steel structure that is to be cut, a member to be cut may be provided with a pilot hole or a tapped hole in advance, and more preferably, a tapped hole in advance. And a bolt may be inserted into the tapped hole.

  In the embodiment of FIG. 1, the embodiment has been described in which the bolt 20 screwed into the tap hole 16 is applied to the back member 2 and further screwed to apply bending force to the cut portion 3. It is not limited, It is possible to give bending force to a cutting location by various methods.

  For example, a tap hole may be formed in the vicinity of the cut location, a bolt may be screwed into the tap hole, and the screwed bolt may be continuously pulled in a direction opposite to the direction in which the bolt is screwed to apply the bending force. Further, a bending force may be applied by continuously pressing the vicinity of the cut portion from the laser irradiation surface side with a jig or the like. Further, when the laser irradiation surface of the material to be cut faces downward in the vertical direction, for example, when cutting the ceiling plate or the like by irradiating the laser from below, a weight is joined to the lower surface of the ceiling plate, A bending force may be applied to the cut portion by the weight of the weight. Note that the method of applying a bending force is more effective when the laser is cut in the embodiment of FIG. 1 or the embodiment in which the above-described weight is joined than the embodiment in which the above-described bolt is continuously pulled or pressed with a jig or the like. This is preferable because an aggressive driving force is not required to apply the force. In particular, the embodiment of FIG. 1 is more preferable because the direction of the laser irradiation surface of the material to be cut is not selected.

  In the present embodiment, the embodiment in which the method for preventing re-adhesion at the time of laser cutting according to the present invention is applied when the cut piece 29 is separated from the workpiece 1 by laser cutting has been described. However, the present invention is not limited to this. However, for example, when slitting is performed on the material to be cut by laser cutting, the method for preventing re-adhesion at the time of laser cutting according to the present invention may be applied.

  In the present embodiment, the form in which the material 1 to be cut by laser is a plate-like rib made of steel has been described. However, the present invention is not limited to the shape of the material to be cut. A side plate of a cylindrical tank may be used.

  In the present embodiment, a YAG laser is used as the laser. However, the present invention is not limited to this, and for example, a carbonic acid laser may be used.

  Further, in the embodiment of FIG. 1, an operation of making the pilot hole 21 of the tap hole 16, an operation of cutting a female screw into the pilot hole 21, an operation of screwing the bolt 20 into the tap hole 16, and laser irradiation to the cutting portion 3. However, the present invention is not limited to this, and part or all of these operations may be performed manually.

The perspective view for demonstrating the re-adhesion prevention method at the time of the laser cutting of the to-be-cut material by one Embodiment which concerns on this invention is shown. The front view of a to-be-cut material and the cutting location 3 of the to-be-cut material is shown. (A) shows the perspective view of a robot. (B) shows a side view of the laser cutting device, (c) shows a side view of the screw tap, and (d) shows a side view of the hexagon wrench. The top view of the state which opened the prepared hole of the tap hole in the to-be-cut material is shown. The top view of the state which cut the internal thread in the pilot hole of the tap hole of a to-be-cut material is shown. The top view of the state which screwed the volt | bolt in the tap hole until the front-end | tip of a volt | bolt hits a back side member is shown. FIG. 7 is a plan view of a state where a bolt is further screwed from the state of FIG. The enlarged plan view of the cutting location after laser cutting is shown. The top view of the state which cut | disconnected all the cutting locations is shown. The work site of the laser cutting operation which can apply the re-adhesion prevention method at the time of laser cutting of this embodiment is shown. FIG. 11 shows a detailed perspective view of FIG. 10. The other embodiment which concerns on this invention is shown, and the to-be-cut material and the bolt screwed in the to-be-cut material are shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material to be cut 2 Back side member 3 Cut location 16 Tap hole 20 Bolt

Claims (2)

  When cutting a material to be cut using a laser, a bending force is applied in advance to the cut portion of the material to be cut, and the laser is irradiated to the cut portion in that state for cutting. Re-fixing prevention method. When cutting the material to be cut using a laser in a state where a back side member such as a plate material is provided at a distance from the material to be cut on the back side of the material to be cut, in the vicinity of the cutting portion of the material to be cut A tapped hole is drilled, a bolt is screwed into the tapped hole, the tip of the bolt is applied to the back side member and further screwed to impart a bending force to the material to be cut, and in this state, the laser is irradiated to the cutting location And a method for preventing re-adhesion during laser cutting.

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