JP2005081394A - Cutting method of steel wire wound on bobbin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting method of a steel wire wound on a bobbin, which can efficiently cut and remove a used steel wire wound on a bobbin without damaging the bobbin. <P>SOLUTION: Positions of a torch nozzle 11 and a bobbin 7 are relatively adjusted so that a shifting between a laser optical axis of the torch nozzle 11 of a laser machine 1 and the center axis of the bobbin comes to a designated shifting amount S. While the laser beam of a designated intensity is irradiated to a designated position of the wound wire and at a designated timing, at least one of the torch nozzle and the bobbin is moved relatively to the other in the axis direction of the bobbin so that the laser beam irradiation range goes across the wound wire 8. The laser beam irradiation range is continuously or intermittently shifted between one end and the other end in the width direction of the bobbin so that the laser irradiation range repeatedly goes across the wound wire to cut off the wound wire. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bobbin-wound steel wire cutting method in which a bobbin winding wire used for cutting a semiconductor wafer is cut and separated to recover and reuse the bobbin.

  In the field of manufacturing semiconductor basic materials, a silicon wafer is cut out from a silicon single crystal ingot using a wire saw machine. In the wire saw machine, as shown in FIG. 6, a cutting agent containing abrasive grains while feeding a thin wire 8 from a feeding bobbin 7 on one side to a winding bobbin 7 on the other side at a substantially constant speed. Is supplied to the wire 8 and the work 9 made of a silicon single crystal ingot is gradually fed toward the pass line of the wire 8 so that the work 9 is thinly cut in a direction perpendicular to the ingot axis.

  The used wire 8 is wound around the same bobbin 7 as at the time of shipment. However, since the bobbin 7 is a high-precision processed product with high price, only the wire 8 is discarded and the bobbin 7 is collected and reused. . In order to collect the bobbin 7, it is necessary to separate the used wire 8 from the bobbin 7.

  However, since the used wire 8 is wound around the bobbin 7 with the abrasive grains of the cutting agent attached, if the wire 8 is rewound by a normal wire feeding device, the wire guide and its peripheral members are worn. In actuality, the used wire 8 cannot be rewound, because it is damaged and falls into a state where it cannot be fed in a short time.

  Therefore, the wire 8 is gas-cut while being wound around the bobbin 7, the wire 8 is separated and peeled off from the bobbin 7, and the bobbin 7 is emptied and reused. ing. In such a conventional gas cutting method, as shown in FIG. 7 and FIG. 8, the flame of the gas burner 100 is applied to the winding wire 8 along the cutting line 74 crossing the winding wire 8 and heated and melted. Cut (melt).

In addition, the use of a laser cutting method instead of the conventional gas cutting method is an issue to be studied. The laser cutting method is described in, for example, Patent Document 1 and Patent Document 2, respectively.
Japanese Patent No. 3326138 Japanese Patent Laid-Open No. 10-137958

  However, in the conventional gas cutting method, since a large amount of spatter and dross are generated before the inner layer of the wound wire reaches the perforation, the surface of the bobbin is contaminated by the adhesion of these foreign substances. In addition, the conventional gas cutting method increases the amount of heat transferred to the bobbin via the winding wire, and the thermal damage received by the bobbin is significant, resulting in thermal distortion deformation and fusing damage (perforation) to the reel. There is also. Thus, according to the conventional gas cutting method, there is a risk of damage to the bobbin. Therefore, in order to collect a high-quality bobbin that can withstand reuse, a high level of skill is required of the operator.

  In addition, the laser cutting method of Patent Document 1 is a method in which the resin coating is peeled off from the roller surface for the printer by irradiation with YAG laser light, but the workpiece to be cut is a resin layer different from the metal wire. This cannot be applied to bobbin winding wire cutting.

  Further, the laser cutting method of Patent Document 2 is a method of cutting a metal material by irradiation with pulse YAG laser light using oxygen as an assist gas, but it is intended to eliminate the need for post-processing on the back surface. Since this is a cutting method that penetrates to the back side of the workpiece, it cannot be applied to the bobbin winding wire.

  The present invention has been made to solve the above problems, and is capable of cutting a bobbin-wound steel wire that can efficiently cut and remove a used steel wire wound around the bobbin without damaging the bobbin. Provide a method.

  A bobbin-wound steel wire cutting method according to the present invention is a bobbin-wound steel wire cutting method for cutting a used steel wire while being wound around a bobbin. (A) Laser light of a torch nozzle of a laser beam machine The torch nozzle and the bobbin are relatively aligned so that the shaft and the bobbin central axis have a predetermined shift amount S. (b) A laser beam having a predetermined intensity is applied to a predetermined portion of the wound steel wire at a predetermined timing. While irradiating, by moving at least one of the torch nozzle and the bobbin relative to the axial direction of the bobbin, the laser beam irradiation region crosses the wound steel wire from the one end in the width direction of the bobbin. The laser beam irradiation region is moved continuously or intermittently between the ends, and (c) the crossing of the wound steel wire is repeated in the laser beam irradiation region to cut the wound steel wire. It is characterized in.

  In the step (b), laser beam irradiation is started from the central portion in the bobbin width direction, the torch nozzle is moved toward one end portion in the bobbin width direction, and the laser beam irradiation region reaches the one end portion. At that point, the laser beam irradiation is interrupted, the torch nozzle is fed to the central portion in the bobbin width direction, the laser beam irradiation is restarted from the central portion in the bobbin width direction, and the torch nozzle is directed toward the other end in the bobbin width direction. The laser beam irradiation can be stopped when the laser beam irradiation region reaches the other end. By adopting such a center start one-way method from the initial stage to the middle stage of cutting, it is possible to ensure laser beam irradiation with excellent punchability and to reach the inner layer of the wound steel wire in a short time. be able to. Depending on the thickness of the wound steel wire, the first layer, the second layer, the third layer, etc., and the center start one-way method can be repeated in sequence. Finally, it is preferable to finish-cut using the following end start reciprocation method.

  In the step (c), the wound steel wire can be finished and cut by reciprocating the torch nozzle at least once between the end on one side and the end on the other side in the bobbin width direction. it can. By adopting such an end start reciprocating system in the latter stage of cutting, continuous finish cutting is ensured, and a relatively clean cut surface can be obtained from the outer layer to the inner layer of the wound steel wire. In the finish cutting, the number of reciprocations of the torch nozzle can be increased to 1.5 times, 2, 2.5 times, 3 times, etc. as the thickness of the wound steel wire increases. However, if the number of reciprocations of the torch nozzle is excessively increased, not only will the number of work steps increase and costs will increase, but the amount of heat transferred to the bobbin may increase, causing thermal deformation, and there is a risk of holes in the reel. is there. For this reason, the number of reciprocations of the torch nozzle in finish cutting is preferably up to 3 times, and most preferably 1 to 2 times.

  As the laser processing machine, a carbon dioxide laser processing machine having a gas supply mechanism for supplying a plurality of types of assist gas can be used. In this case, it is preferable to supply the assist gas which mixed 1 type or 2 types or more from the gas supply mechanism to the torch nozzle according to cutting conditions. Oxygen, nitrogen, and air can be used as the assist gas for the carbon dioxide laser beam machine, and a mixed gas thereof can be used, but it is most preferable to use a mixed gas of oxygen and nitrogen.

  Furthermore, it is preferable that the torch nozzle is provided with a protective member for protecting from laser reflected light. Steel wire for cutting semiconductor wafers is a high-carbon steel (C: 0.82%) thinly brass-plated, so it has high reflectivity, and the laser reflected light reflected from it is high-energy and dangerous. This is because the torch nozzle and its surrounding members are damaged. Usually, the reflectance of the metal material is as high as 95% or more at the wavelength of the YAG laser and 98% or more at the wavelength of the carbon dioxide laser. In addition, these materials have high thermal conductivity, and it is difficult for laser energy to enter the workpiece, so that they are not suitable for ordinary laser cutting. When a YAG laser is used, a pulse laser processing machine having a peak value of 5 kW or more and an average output of 500 W or more is required. Similarly, when a carbon dioxide laser is used, a processing machine having an average output number of kW is required. However, the cut finish surface of the workpiece by these devices is cut at the laser beam converging angle, and a sharp blade-like finish surface remains at the cut end of the back surface of the workpiece. Moreover, a residue may adhere to the back surface of the workpiece.

  Incidentally, the reflectivity of iron is 65% at the wavelength of the carbon dioxide laser, which is low compared with 95% of the reflectivity of gold. Furthermore, when steel that has been subjected to black coating or blackening treatment is used instead of iron, the reflectance is low. Also, the thermal conductivity is low. When the laser light is incident on the surface iron, iron alloy or steel, it reacts with oxygen to become iron oxide, and instantaneously reaches 2 to 3000 ° C. by the reaction heat at this time. This heat is transferred to the workpiece and the temperature rises. When the temperature of the workpiece increases, the reflectivity of the laser beam decreases, and the absorption rate increases accordingly. In the molten state, the absorption rate is 50%. Moreover, since the upper and lower sides of the workpiece are sandwiched between the covering materials, there is a heat retaining effect. Since laser cutting is thermal processing, the increase in absorption rate and the heat retention effect increase the efficiency of laser cutting. The surface temperature of the workpiece rises with the irradiation time of the laser beam, reaches the melting point of the workpiece and melts, and finally reaches the boiling point to perform drilling. Incidentally, the laser beam at the time of cutting attenuates in the thickness direction. This is because the laser beam is absorbed by the side wall which is the cut surface while being irregularly reflected in the cut groove. Due to this attenuation, the noble metal on the back side melts, but does not reach evaporation but remains as a melt.

  According to the present invention, after the bobbin is fixed to the jig, the laser cutting machine repeats the automatic control operation according to the initial setting program to cut the bobbin winding wire, so that individual differences can be made without depending on the skill level of the operator. A cutting process without any problem is realized. By the way, in the conventional method, considerable skill was required to cut the wire so as not to damage the bobbin (with dents etc.), resulting in considerable individual differences in work results depending on the skill of the operator. However, it was possible to completely eliminate such variations caused by the skill level.

  In addition, according to the present invention, even if the wire has poor linearity, welding does not occur due to the assist gas, and operations such as hitting with a hammer become unnecessary, and workability is better than conventional gas fusing methods. is there.

  In addition, according to the present invention, since the cutting width is narrowed, the amount of dross generated is smaller than that of conventional gas fusing, and the bobbin itself is not heated, so that the dross does not adhere to the bobbin.

  In addition, according to the present invention, the thermal effect at the time of cutting is not substantially received, the machining accuracy is high, and the bobbin is not damaged, so that the life of the bobbin is greatly extended.

  Further, according to the present invention, since the heated and melted portion is limited to only a narrow region, the temperature of both the wire and the bobbin is only slightly increased, and there is no danger of the operator getting burned. In addition, since the amount of assist gas oxygen used is optimized and the cutting width is narrow, the amount of oil smoke generated when the wire is blown is small, and the working environment is greatly improved as compared with the prior art.

  Furthermore, according to the present invention, since the time required for cutting per bobbin is shortened, the operation cost can be reduced to about 80% as compared with the conventional gas cutting method.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the carbonic acid laser processing machine 1 of this embodiment includes three assist gas supply sources 2, 3, and 4 that supply different gas types. The first gas supply source 2 is oxygen, the second gas supply source 3 is nitrogen, and the third gas supply source 4 is air as an assist gas via a gas supply pipe 21, 31, 41 through a laser torch unit. It supplies to 10 gas introduction parts 13 (refer FIG. 2, FIG. 3). The laser torch unit 10 having the assist gas introduction unit 13 is described in detail as a laser processing nozzle in which an optical system and a gas introduction unit are combined in, for example, Japanese Patent Application Laid-Open No. 2000-312986.

  The three gas supply pipes 21, 31, and 41 are connected to internal pipes 61, 62, and 63 of the laser device main body 60 through stop valves 25, 35, and 45, respectively. Pressure regulators 65a to 65d and solenoid valves 66a to 66d are provided in the internal pipes 61, 62, and 63, respectively.

  Further, branch pipes 22, 32, and 42 are branched from the gas supply pipes 21, 31, and 41, respectively, and communicate with the gas mixer 50. The branch pipes 22, 32, 42 are provided with stop valves 23, 33, 43 and pressure regulators 24, 34, 44, respectively. The downstream pipe of the gas mixer 50 is connected to the internal pipe 64 of the laser device main body 60. The internal pipe 64 is provided with a pressure regulator 65d and a solenoid valve 66d.

  The internal pipe 64 and the three internal pipes 61 to 63 communicate with one collective pipe 67 inside the laser apparatus main body 60. As shown in FIG. 2, the collective pipe 67 communicates with the gas introduction part 13 of the laser torch unit 10 outside the apparatus main body 60 so that the assist gas is ejected from the tip of the torch nozzle 11. The assist gas is injected from the nozzle 11 coaxially with the carbon dioxide laser beam.

  In the laser torch unit 10, a tip 12 is detachably attached to the tip of the torch nozzle 11. The main body of the torch nozzle 11 has a water cooling jacket structure, for example. The tip 12 is made of a high heat conductive heat-resistant alloy (for example, copper alloy) that can easily exchange heat with the main body of the torch nozzle 11.

  A condenser lens 14 is provided immediately upstream of the gas introduction unit 13, and a laser beam 16 is sent to the condenser lens 14 from a laser oscillator (not shown) via an optical system. The laser beam 16 that has passed through the condenser lens 14 has a beam diameter reduced to, for example, 1.0 mm, and is irradiated to the irradiation point 73.

  As shown in FIG. 3, the torch unit 10 (excluding the torch nozzle 11) is double protected from the laser reflected light 16a. This is because the body member of the bobbin 7 is also made of aluminum (a general-purpose bobbin material is made of an iron alloy), so that it is necessary to devise so that the laser reflected light 16 a does not return to the torch unit 10. In the present embodiment, a stainless steel plate having a predetermined thickness is used as the first protective member 15a, and an aluminum foil having a predetermined thickness is used as the second protective member 15b.

  As shown in FIG. 3, when the torch unit 10 is positioned at a predetermined laser irradiation position with respect to the bobbin 7 (use positions UP1 to UP3 in FIG. 5 described later), the laser optical axis 16 and the bobbin central axis 71 are The position is shifted so that a predetermined shift amount S is obtained. This is because if the vertex 72 is irradiated with laser light, the reflected light 16a reflected from the vertex 72 may significantly damage the torch unit 10. Therefore, it is preferable that the irradiation point 73 be as far away from the vertex 72 as possible. However, if the shift amount S is excessively increased, the center angle θ in the figure (the angle formed by the line connecting the irradiation point 73 and the bobbin center point with the bobbin center line 71) becomes too large, and the amount of energy incident on the winding wire 8. Therefore, the shift amount S is preferably in a range where the central angle θ does not exceed 30 °.

  The shift amount S is appropriately determined according to various conditions such as the bobbin size (the outer diameter of the winding wire 8) and the surrounding work environment. For example, when the bobbin diameter is 254 mm, the shift amount S can be 20 mm, and when the bobbin diameter is 300 mm, the shift amount S can be 25 mm.

  An embodiment of the laser cutting method will be described with reference to FIGS.

  As shown in FIG. 5A, the bobbin 7 on which the used saw wire 8 is wound is placed between a pair of left and right clamps 19 on the pedestal 18, and the bolt shaft 17 is attached to the hole of the clamp 19 and the bobbin 7. It was inserted into the center hole and fastened with a nut (not shown). The bobbin 7 was fixed on the pedestal 18 so that the axis was horizontal.

  Next, at least one of the torch unit 10 and the pedestal 18 was moved, and the laser cutting system 1 and the bobbin 7 were relatively aligned. The relative alignment between the two is performed by fixing the pedestal 18 so as not to move to a predetermined position in advance, and by setting the home position HP of the torch unit 10 at a predetermined position in advance. This is possible with a simple operation by simply aligning with the home position HP.

  In the bobbin 7, the bundle width center of the bobbin winding wire 8 is located immediately below the first use position UP1, and one end in the bundle width direction of the bobbin winding wire 8 is located directly below the second use position UP2. The winding wire 8 was mounted on the pedestal 18 so that the other end in the bundle width direction was positioned immediately below the third use position UP3.

  After the relative alignment between the bobbin 7 and the torch unit 10, the auto control switch of the laser beam machine 1 is turned on to shift to a fully automatic cutting operation by computer NC control. The fully automatic cutting operation will be described with reference to FIG. In the timing chart of FIG. 5B, the thin line represents the period during which laser cutting is performed, and the broken line represents the period during which laser cutting is interrupted or stopped and the torch unit is idled.

At timing t ₀ , a command signal is sent from the controller (not shown) of the laser cutting system to the power supply circuit of the torch moving mechanism (not shown). Accordingly, the torch unit 10 moves from the home position HP toward the first use position UP1 (bobbin width center). During the period from timing t ₀ to timing t ₁ , the torch unit 10 is idle fed.

At timing t ₁ , laser beam irradiation was started from the torch nozzle 11 to cut the bundle wire 8. The cutting operation interval of the first layer is from the first use position UP1 to the second use position UP2, the cutting operation period was from the timing t ₁ to timing t _2.

Laser light irradiation was interrupted at timing t ₂ , and the torch unit 10 was preliminarily fed from the second usage position UP 2 to the first usage position UP 1 (period from timing t ₂ to timing t ₃ ).

Laser irradiation was resumed at timing t ₃ , and cutting was performed by irradiating laser light from the first usage position UP1 to the third usage position UP3 (period from timing t ₃ to timing t ₄ ).

The laser beam irradiation was interrupted at timing t ₄ , and the torch unit 10 was returned to the home position HP while being fed from the third use position UP 3 (period from timing t ₄ to timing t ₅ ).

After a predetermined time (period t ₅ ~t ₆₎ elapses, at the timing t _6, were idle feed move to the torch unit 10 from the home position HP first use position UP1. It resumes the laser light irradiation timing t _7, and performs a disconnect is irradiated with a laser beam from the first use position UP1 to the second use position UP2 (period from the timing t ₇ to the timing t _8).

Interrupting the laser light irradiation timing t _8, and the torch unit 10 from the second use position UP2 to the first use position UP1 idle feed and (period from the timing t ₈ to the time t _9).

It resumes the laser light irradiation timing t _9, and performs a disconnect is irradiated with a laser beam from the first use position UP1 to a third use position UP3 (period from the timing t ₉ to the time t _10).

Interrupting the laser light irradiation timing t _10, and returned to the home position HP while idle feeding the torch unit 10 from the third use position UP3 (period from the timing t ₁₀ to the timing t _11).

After a predetermined time (period t ₁₁ ~t ₁₂₎ elapses, at the timing t _12, were idle feed move to the torch unit 10 from the home position HP second use position UP2. Next, the torch unit 10 was raised, and the height level of the torch nozzle was increased by about 20 mm from that in the first and second layers.

Resumes the laser light irradiation timing t _13, the torch unit 10 is moved from the second use position UP2 to the third use position UP3 through the first use position UP1, further third use position UP3 From the second use position UP2 through the first use position UP1 to the third use position UP3. During this time, the first use position UP1 is passed through to the second use position UP2. executing the cutting by continuously irradiating a laser beam (the period from the timing t ₁₃ to the timing t _16). Thus, the winding wire 8 was finished and cut by moving the torch unit 10 once and a half reciprocatingly between the end on one side and the end on the other side in the bobbin width direction.

Stop the laser light irradiation timing t _16, and returned to the home position HP while idle feeding the torch unit 10 from the third use position UP3 (period from the timing t ₁₆ to the timing t _17).

Next, the processed bobbin 7 is removed from the pedestal 18 and conveyed to another place, and the cut wire 8 is peeled off from the bobbin 7. On the other hand, the unprocessed bobbin 7 is attached to the base 18. After replacing the bobbin 7 in this way, the automatic cutting operation was resumed at the reset predetermined timing t ₀ , and the next winding wire 8 was cut in the same manner as described above.

One cycle time t _{0 to} t ₁₇ of the cutting process of this example was about 3 minutes when the bobbin size was 254 mm in diameter and about 3 minutes when the bobbin size was 300 mm in diameter.

  The cutting conditions of this example are shown below.

1) Bundle wire: Brass wire plated on 0.16mm diameter steel wire (carbon content 0.82%)
: Abrasive (average 1.7 g / kg) adhering 2) Assist gas: Initially 120 liters / minute of air, mixed gas of 0.45 MPa and oxygen 20 liters / minute, 0.45 MPa
: Oxygen (purity 99.8% or more) 20 liters / minute at the end, 0.45 MPa alone 3) Laser peak output: 4 kW
4) Beam diameter: 1.0mm
5) Torch moving speed: 430 mm / min (first to second layers)
: 1000 mm / min (finishing layer)

  According to the present invention, it is possible to efficiently cut and remove a used steel wire (saw wire) cut out of a semiconductor wafer wound around a bobbin without damaging the bobbin. According to the present invention, since the time required for cutting per bobbin is shortened, the operation cost can be reduced to about 80% as compared with the conventional gas cutting method.

The block circuit diagram which shows the laser cutting device used for the method of this invention. The block circuit diagram which shows the principal part of the laser cutting apparatus used for the method of this invention. The side surface schematic diagram which shows the torch part and bobbin of the laser cutting apparatus used for the method of this invention. The front schematic diagram when cut | disconnecting a bobbin winding steel wire using the method of this invention. (A) is a figure which shows a bobbin winding steel wire typically in order to demonstrate this invention method, (b) is a timing chart explaining operation | movement when a bobbin winding steel wire is cut | disconnected by this invention method. The schematic diagram when cutting out a semiconductor wafer with a saw machine. The figure which shows the conventional gas cutting method seeing from the side. The figure which shows the conventional gas cutting method seeing from the front.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laser processing machine 2, 3, 4 ... Gas supply source 7 ... Bobbin, 8 ... Saw wire (steel wire), 9 ... Work 10 ... Laser torch unit, 11 ... Torch nozzle, 12 ... Tip tip 13 ... Gas introduction part, 14 ... Condensing lens 15a ... Protective member (stainless steel plate), 15b ... Protective member (aluminum foil)
DESCRIPTION OF SYMBOLS 16 ... Irradiation light (laser optical axis), 16a ... Reflected light 17 ... Shaft, 18 ... Base, 19 ... Clamp 21, 31, 41 ... Gas supply pipe 22, 32, 42 ... Branch pipe 23, 33, 43 ... Stop valve 24, 34, 44 ... pressure regulators 25, 35, 45 ... stop valve 50 ... gas mixer 60 ... laser device body 61-64, 67 ... internal piping 65a-65d ... pressure regulators 66a-66d ... solenoid valve 71 ... Bobbin center line 72 ... vertex 73 ... irradiation point 74 ... cutting line

Claims (5)

In a bobbin-wound steel wire cutting method for cutting a used steel wire while being wound around a bobbin,
(A) The torch nozzle and the bobbin are relatively aligned so that the laser optical axis of the torch nozzle of the laser processing machine and the bobbin central axis have a predetermined shift amount S;
(B) A laser beam is obtained by relatively moving at least one of the torch nozzle and the bobbin in the axial direction of the bobbin while irradiating a predetermined portion of the wound steel wire with a laser beam having a predetermined intensity at a predetermined timing. The laser beam irradiation region is moved continuously or intermittently from one end to the other end in the width direction of the bobbin so that the irradiation region crosses the wound steel wire,
(C) A method for cutting a bobbin-wound steel wire, wherein the laser beam irradiation region is repeatedly traversed by a wound steel wire to cut the wound steel wire. In the step (b), laser beam irradiation is started from the center portion in the bobbin width direction, the torch nozzle is moved toward one end portion in the bobbin width direction, and the laser beam irradiation region reaches the one end portion. Then, the laser beam irradiation is interrupted, the torch nozzle is fed to the central portion in the bobbin width direction, the laser beam irradiation is started again from the central portion in the bobbin width direction, and the torch nozzle is moved to the other side in the bobbin width direction. 2. The method according to claim 1, wherein the laser beam irradiation is stopped when the laser beam irradiation region reaches the other end portion. In the step (c), the wound steel wire is finished and cut by reciprocating the torch nozzle at least once between one end in the bobbin width direction and the other end. The method according to claim 1 or 2. The laser processing machine has a gas supply mechanism for supplying a plurality of types of assist gas, and supplies assist gas mixed with one or more types from the gas supply mechanism to the torch nozzle according to cutting conditions. The method according to any one of claims 1 to 3. The method according to claim 1, wherein the torch nozzle is provided with a protective member for protecting from laser reflected light.

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