JP2018144112A - Wire saw cutting method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire saw cutting method by which cutting efficiency is greatly improved and an operation time can be shortened.SOLUTION: When cutting a cutting object in such a manner that a wire saw 10, in which plural cutting beads 11 are additionally provided on a wire at a prescribed pitch, is bridged between plural guide pulleys and a drive pulley in an endless state, and the wire saw is pressed onto the cutting object, and at the same time, the wire saw is travelled, both or one of a pressing force of the cutting bead and a travel speed of the wire saw is set or adjusted so that an orientation direction of a synthetic vector C1 of a pressing force vector T1 of the cutting bead 11 and a travel speed vector F1 of the wire saw 10 approaches an optimum cutting direction vector of the cutting bead.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a wire saw cutting method and apparatus, and more particularly to a method and apparatus capable of greatly improving cutting efficiency and shortening work time.

  Recently, the decommissioning problem of nuclear power plants has attracted attention, but such decommissioning requires safe dismantling of reinforced concrete structures such as buildings and metal structures. Various methods such as blasting, water jets or cutting blades are known for dismantling buildings, but a cutting method using a wire saw has also been proposed for dismantling decommissioning buildings and power generation facilities.

  For example, a wire saw in which a plurality of ultra-hard beads are attached at a predetermined pitch is wound around a stainless steel heat exchanger, and the wire saw is run at a speed of 3 to 10 m / sec while applying a tension of 100 to 180 kgf to the wire saw. Although a method of cutting and disassembling a stainless steel heat exchanger is known (Patent Document 1), as expected when cutting and disassembling structures of different dimensions or materials under such setting conditions Efficient cutting is not possible, requiring a long working time in a radiation control area with a high radiation dose, and there is concern about radiation exposure.

  On the other hand, the present applicants made the shank of the cutting bead a shape having at least a curved surface shape that bulges in a convex shape so that the outer diameter increases toward the rear in the feed direction, and the curved surface of the shank A layer of cutting diamond is formed on the outer surface of the shape portion, and a wire saw formed by attaching a plurality of cutting beads to the wire at a predetermined pitch is spanned endlessly between a plurality of guide pulleys and a driving pulley, Proposes a technique to cut the cutting object by pressing it against the cutting object such as a reinforced concrete structure and running the wire saw at a speed that maximizes the torque of the drive motor within a range of 5 to 20 m / sec. (Patent Document 2).

JP 2005-153071 A Japanese Patent Laying-Open No. 2015-136853

  Although it has been confirmed that the wire saw cutting method described in Patent Document 2 can shorten the work time compared with the method described in Patent Document 1, the cutting theory is not clear and the material of the cut material is various such as concrete and various metals. In order to apply it to the cutting and dismantling of nuclear power plant structures of different sizes, etc., the wire saw cutting theory is analyzed in detail to establish appropriate conditions, and the cutting efficiency is greatly improved. It is desired to further reduce the cutting work time by extending the severable life of the wire used.

The present invention has been made in such a situation, and an object of the present invention is to provide a wire saw cutting method capable of shortening the working time by greatly improving the wire saw cutting efficiency and extending the wire life.

  Therefore, in the wire saw cutting method according to the present invention, a wire saw in which a plurality of cutting beads are attached to a wire at a predetermined pitch is spanned between a plurality of guide pulleys and a drive pulley in an endless manner. When pressing the wire against the object to be cut and running the wire saw to cut the object to be cut, the bead pressing force vector determined by the wire tension that becomes the cutting force of each cutting bead contacting the object to be cut and Focusing on the importance of the direction of the combined vector with the speed vector determined by the traveling speed of the wire saw, and for cutting so that the cutting beads approach the optimal cutting direction vector that efficiently cuts the object to be cut. Set or adjust bead pressing force and / or wire saw travel speed, preferably during cutting Characterized in that so as to arbitrarily set or adjusted.

  Moreover, the wire saw cutting device according to the present invention is an endless wire saw formed by attaching a plurality of cutting beads to a wire at a predetermined pitch in a wire saw cutting device that cuts an object to be cut with a wire saw, A plurality of guide pulleys for pressing the wire saw against an object to be cut and guiding the traveling of the wire saw; and a driving pulley having a minimum outer diameter that allows the wire saw to travel up to a maximum speed of 14 m / s; A drive motor capable of rotating the drive pulley so that the rotational torque of the drive pulley is constant and maximum between 3 and 14 m / s of the wire traveling speed, and a tension means for applying tension to the drive pulley; The combined vector of the pressing force vector T1 of the cutting beads and the traveling speed vector F1 of the wire saw Arbitrary without stopping the traveling during cutting of either or both of the pressing force of the cutting beads and the traveling speed of the wire saw so that the direction of C1 approaches the direction of the pressing force of the cutting beads to the cutting object And a controller that can be set or adjusted.

Here, the work of the wire saw is analyzed. As shown in FIG. 1, the rotation speed (rpm) of the drive pulley is A, the force (kgf) for pulling the wire saw is F, the wire tension (kgf) is T, and the contact length of the wire saw to the object to be cut (m ) Is L, and the wire saw traveling speed (m / s) is V, the work amount of the wire saw for one second is W = F × V.
F is the total sum of the forces of the individual cutting beads that are in contact with the object to be cut to stop the wire saw.
Analyzing the vector representing the magnitude and direction of the force applied to the cutting beads that are in contact with the cutting object when the wire is running, 1) the vector of the force F of the force F that pulls the wire saw generated by the rotation of the drive pulley ( F1), 2) vector of force applied to each cutting bead by tension T applied to the wire (T1), 3) vector of force applied to the cutting object of each cutting bead generated by component force vector T1 (P1) 4) A vector (S1) of the component force in the running direction of each cutting bead generated by the component force vector T1, and a vector (C1) representing the direction and magnitude of the cutting force of each cutting bead is the F1 + S1 vector. (Cutting bead traveling direction) and a component force vector (P1) in which each cutting bead holds the object to be cut. This vector C1 serves as a cutting force of each cutting bead 11.
In FIG. 5, the cutting waste 12 generated by cutting the individual cutting beads 11 stays on the cutting surface of the object to be cut as the cutting progresses, and this becomes a force (k1) that hinders the progress of the individual cutting beads 11. .
Further, as shown in FIGS. 2A to 2C, when the cutting waste 12 generated by cutting stays on the cutting surface of the object to be cut as the cutting progresses, the cutting waste 12 and the cutting beads 11 are obtained. Heat and heat 13 are generated by the friction caused by this friction and the friction caused by the high-speed running of the cutting beads 11, which becomes a work loss of the wire saw. The total weight of the wire saw can be sufficiently ignored in view of the force required for cutting. However, in the case of underwater cutting, resistance (M) of a magnitude that cannot be ignored may be added.

That is, the work of the wire saw can be generally expressed by the following relational expression.
W = F × V = {(C1 × V + k1 × V) × number of beads} + heat generation due to friction Here, F is caused by T, and T is a synthetic force applied to each cutting bead contacting the object to be cut. It is approximately equal to the sum of (C1) and the force (k1) that hinders the progress of the cutting beads. In order for the work W given to the cutting distance L of the object to be cut to change to cutting, it is important to increase the combined force (C1).
To that end, 1) remove the accumulated cutting waste and reduce k1, 2) eliminate the accumulated cutting waste, rotate the cutting beads smoothly, and 3) increase the tension (T) to cut the cut surface. It can be understood that it is important to concentrate the component force in the direction, and 4) to reduce the traveling speed because the kinetic energy of each cutting bead is 1/2 · (C1 + k1) V ² . That is, if the pressing force of the cutting beads is increased, the traveling speed is decreased, the cutting waste is eliminated, and the frictional heat is reduced, the cutting energy can be dramatically converted.
However, if the pressing force of the cutting beads is increased infinitely and the traveling speed is reduced to zero as much as possible, the cutting bead is directed to the cutting object direction rather than the appropriate vector direction that produces efficient cutting bead cutting. The excessive collision phenomenon of the bead to the object to be cut occurs, which may cause breakage of the wire and excessive wear of the cutting bead. Therefore, it is important to match the traveling speed V and C1.

  In addition, the wire saw is pre-twisted and the cutting beads are rotated around the wire so that the diamond abrasive grains adhering to the entire circumference of the cutting beads are properly dropped as the cutting progresses to maintain the cutting ability. It is known that it is better to run while running.

  One of the features of the present invention is that cutting is performed so that the direction of the combined vector of the pressing force vector of the cutting bead and the traveling speed vector of the wire saw approaches the appropriate cutting direction of the cutting bead with respect to the cutting target. It is in the point that either or both of the pressing force of the beads and the traveling speed of the wire saw are set or adjusted, preferably arbitrarily set or adjusted during cutting.

Thereby, cutting efficiency can be improved significantly, for example, since the building of a nuclear power plant can be demolished in a short time, the concern of radiation exposure can be eliminated.
Further, the cutting method of the present invention is not limited to the demolition of a building of a nuclear power plant, but can be applied to the demolition of a bridge, a large plant, a large building, and the like.
Note that the appropriate (optimal) cutting direction of the cutting beads varies depending on the physical properties of the object to be cut, and it is preferable to obtain in advance according to the physical properties of the object to be cut. By setting or adjusting the pressing force of the cutting beads and / or the traveling speed of the wire saw according to the situation, the direction of directing the combined vector of the pressing force vector of the beads and the traveling speed vector of the wire saw can be changed. It is also possible to approach the proper (optimal) cutting direction of the cutting beads.

  The pressing force of the cutting bead is determined by the tension of the wire saw and the number of cutting beads in contact with the cutting surface. The higher the tension of the wire saw, the greater the pressing force of the cutting bead on the object to be cut. can do. However, when the tension of the wire saw is increased, there is a concern about an accident due to the breakage of the wire. Therefore, the upper limit is preferably a size obtained by multiplying the breaking strength of the wire saw by the safety factor.

  For example, many wire saws currently in circulation have a rope diameter of about 5 mm, a cutting bead diameter of 9-12 mm, a cutting bead length of 2-8 mm, and a breaking strength of 2000 kgf. When such a wire saw is employed, it is preferable that the safety factor is 50%, the upper limit of the tension of the wire saw is 1000 kgf, and a large tension is applied within the range below that. In particular, it is preferable that the tension of the wire saw can be appropriately adjusted during cutting according to the cutting situation.

As the traveling speed of the wire saw is lower as described above, the cutting energy can be improved and the cutting waste adheres to the wire saw and is discharged, so that the traveling speed is set to 3 m / sec or more.
The traveling speed of 3 m / sec or more is that the cutting bead collides with the work piece excessively as a result of being directed too far below the suitable cutting direction vector of the cutting bead as described above. This is the lower limit speed limit at which excessive wear of the cutting beads occurs extremely.
It has been found that when the traveling speed exceeds 14 m / sec, a phenomenon that the wire saw cutting beads 11 are lifted from the cut surface of the object to be cut occurs as shown in FIG. That is, as shown in FIG. 3, the kinetic energy due to the traveling of the wire saw increases as the wire speed increases, but when the traveling speed exceeds 14 m / sec, the thermal energy increases dramatically, but the cutting It was found that energy did not increase substantially. Therefore, it is preferable to set the traveling speed of the wire saw to a speed selected from a range of 3 m / sec to 14 m / sec.

  Specifically, when the object to be cut is a metal, the traveling speed should be 10 m / sec or less, and the individual pressing force of the cutting beads should be 3 kgf / average or more. In the case of concrete, the traveling speed is 14 m. / Sec or less, and the pressing force of each cutting bead is preferably 1.5 kgf / piece or more on average.

  By the way, the cutting waste shows the behavior of the powder fluid, and if it stays between the cutting bead and the cut surface, the cutting bead and the staying cutting waste rub against each other to generate frictional heat, resulting in energy loss. In addition, when the amount of accumulated cutting waste increases, the optimum contact of the cutting beads is obstructed, or in the worst case, the cutting beads float on the cutting waste, such as the hydroplaning phenomenon of a car tire in the rain. Wake up. Accordingly, when the cutting efficiency is greatly improved and the amount of cutting per unit time is increased, the amount of cutting waste generated is also greatly increased, so how to discharge the cutting waste becomes important.

Therefore, the traveling path of the wire saw is covered with a dust collecting cover, air is fed from the front side of the wire saw traveling on the dust collecting cover, and the cutting waste staying on the cutting surface is separated from the cutting surface, so that the traveling side of the wire saw The air is sucked together with the cutting swarf that has been removed, and the cutting swarf is separated by a filter. Then, all or a part of the sucked air is returned to the dust collecting cover and used for the supply air. At this time, if the air feeding speed and suction speed are higher than the wire saw traveling speed so that the cutting waste is discharged smoothly, and the air suction amount is larger than the feeding amount, the air is collected. The area surrounded by the dust cover is decompressed, and dust such as cutting dust can be prevented from being scattered around.
In addition, a cutting agent is applied to the wire saw to cool and wash the wire saw and reduce the friction of the cutting beads. However, the cutting agent can be applied using the above-described supply air. Appropriate amounts of water, surfactant, and lubricant can be used as the cutting agent, and it is preferable to spray this onto the wire saw using the supply air.

The wire saw cutting method according to the present invention has a large effect when applied to dry cutting, but can also be applied to wet cutting.
Further, the wire saw cutting method according to the present invention may be a drawing method as shown in FIG. 4 or may be a push-off method as shown in FIG. 6 and is selected according to the situation of the dismantling site. It is good to do.

  The wire saw cutting abrasive grains are preferably diamond abrasive grains, but may be other super hard abrasive grains. The cutting abrasive grains can be fixed to the shank of the cutting beads by sintering, plating, or brazing.

It is a figure for demonstrating the wire saw cutting | disconnection theory which concerns on this invention. It is a figure for demonstrating the said cutting | disconnection theory. It is a figure which shows the relationship between the cutting energy and heat energy with respect to the kinetic energy of a wire, and a wire speed. It is a top view which shows the example which formed the outer periphery shape in the shape corresponding to electric field mode distribution. It is a schematic structure figure showing a preferred embodiment of a wire saw cutting device concerning the present invention. It is a figure which shows the behavior of the bead for cutting in the said embodiment. It is a schematic block diagram which shows 2nd Embodiment.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. 4 and 5 show a preferred embodiment of the wire saw cutting device according to the present invention. In the figure, the wire saw 10 is fixed to a wire having a breaking strength of 2000 kgf, for example, with 40 to 100 beads / m of cutting beads 11 having a bead diameter of φ10 mm (φ9 to 13 mm) and a shank length of 8 mm (2 to 8 mm) at intervals. Configured.

  The wire saw 10 is assembled endlessly with both ends connected, and the wire saw 10 is hung by a line to be cut on an object to be cut, for example, a reinforced concrete structure 30, and passes through the left and right guide pulleys 21 to the drive pulley 20. It is stretched endlessly and twisted.

A drive shaft of a drive motor 22 such as a servo motor that generates a constant rotational torque in a wide range of rotation is connected to the drive pulley 20 directly or via a reduction gear group, and a pulling mechanism 23 is connected to the drive pulley 20 as a shock absorber. 32, the drive motor 22 and the pulling mechanism 23 have a tension of the wire saw 10 within a range of 1000 kgf or less, and thereby the pressing force of one cutting bead 11 is 1.5 kgf or more. In addition, the controller 24 is controlled so that the traveling speed of the wire saw 10 becomes a speed selected from a range of 3 m / sec or more and 14 m / sec or less.
The shock absorber 32 prevents the pulling force T of the drive pulley 20 from pulsating due to wire travel, and controls the pulling device 32 so as to be maintained substantially constant at a predetermined pulling force.

Further, the object to be cut 20 is provided with a dust collecting cover 25 so as to cover the traveling path of the wire saw 10, and the dust collecting cover 25 has a feeding port 28 for feeding air into the dust collecting cover 25. A suction port 26 for sucking air in the dust collecting cover 25 is formed on the traveling side of the wire saw 10, and a dust removal device 27 such as a bag filter is provided in the suction port 26 to remove dust. A part of the later air is returned to the feeding port 28.
Here, the air feeding speed from the feeding port 28 and the air suction speed from the suction port 26 are set to be higher than the traveling speed of the wire saw 10, and the air suction amount is higher than the air feeding amount. Set to increase.

  Now, as shown in FIG. 5, when the combined vector of the pressing force vector P1 of the cutting bead 11 and the traveling speed vector F1 + S1 of the wire saw 10 is C1, the traveling speed vector of the wire saw 10 is changed from F1 + S1 to F1 ′ + S1. When it is lowered to, the combined vector C1 ′ approaches the direction of the pressing force. Further, when the pressing force of the cutting beads 11 is increased, similarly, the combined vector can be made closer to the direction of the pressing force.

Therefore, air is fed from the feed port 28 into the dust collecting cover 25, and air is sucked from the suction port 26 to discharge the cutting waste 12, and at the same time, the controller 24 reduces the rotational speed of the drive motor 22 by the controller 24. Further, by controlling the tension T of the pulling mechanism 23 so as to increase, the cutting target 30 can be cut efficiently and in a short time, and the cutting beads 12 are discharged from the cutting surface in sequence, so that the cutting beads are removed. Smooth rotation, elimination of bead wear, reduction of bead wear due to cutting waste, and longer cutting bead life.
According to the experiments by the present inventors, a 1 m × 1 m concrete block with 30 mmφ × 10 reinforcing bars was cut at a wire tension of 100 kg and a traveling speed of the wire saw 10 of 9 m / s. It was confirmed that dry cutting was possible.

FIG. 6 shows a second embodiment, in which the same reference numerals as those in FIG. 4 denote the same or corresponding parts. In this example, the wire saw 10 is stretched in the push-off direction by the four guide pulleys 21 and the drive pulley 20, and can be cut by the push-off method in this way.
According to the experiments by the present inventors, when a block of carbon steel for mechanical structure S35C having a size of 30 cm × 30 cm was cut, it was confirmed that the block could be cut in 25 minutes. In the case of a metal material, heat generation increases, so it is preferable to spray cooling water with the nozzle 29.

DESCRIPTION OF SYMBOLS 10 Wire saw 11 Cutting bead 12 Cutting waste 20 Drive pulley 21 Guide pulley 22 Drive motor 23 Pulling mechanism 24 Controller 30 Cutting object

Claims (7)

A wire saw in which a plurality of cutting beads are attached to a wire at a predetermined pitch is passed between a plurality of guide pulleys and a drive pulley in an endless manner, pressing the wire saw against the object to be cut and running the wire saw. When cutting the object to be cut,
In such a manner that the orientation direction of the combined vector (C1) of the pressing force vector (T1) of the cutting bead (11) and the traveling speed vector (F1) of the wire saw approaches the optimum cutting direction vector of the cutting bead (11). A wire saw cutting method characterized by setting or adjusting both or one of the pressing force of the cutting beads (11) to the cutting object and the traveling speed of the wire saw (10).   Claim that the pressing force of the cutting beads (11) to the cutting object and / or the traveling speed of the wire saw (10) are arbitrarily set or adjusted while maintaining the traveling of the wire saw during cutting. Item 10. A wire saw cutting method according to Item 1.   The diameter of the cutting bead (11) is in the range of 9 to 12 mm, the length is in the range of 2 to 8 mm, and the traveling speed of the wire saw (10) with a breaking strength of the wire of 2000 kgf is 3 to 14 m / The wire saw cutting method according to claim 1, wherein an average pressing force to the cutting object per cutting bead (11) by a speed in the range of s and wire tension (T) is 1.5 kgf or more.   When cutting mainly a metal cutting object, the traveling speed of the wire saw (10) is 10 m / sec or less, and the cutting object (11) per cutting bead (11) of the wire saw (10) The wire saw cutting method according to claim 3, wherein the average pressing force is 3 kgf or more.   When cutting mainly a concrete cutting object, the traveling speed of the wire saw (10) is 14 m / sec or less, and the cutting object (11) per cutting bead (11) of the wire saw (10). The wire saw cutting method according to claim 3, wherein the average pressing force is 1.5 kgf or more.   Cover the traveling path of the wire saw (10) to be cut, cover with the dust cover (25), suck air from the traveling side of the wire saw (10) of the dust cover (25), and suck after dust removal Return a part of the air to the wire saw (10) front side to feed air to the dust cover (25), and make the air suction speed and feed speed faster than the wire saw (10) travel speed. The wire saw cutting method according to claim 1, wherein the air suction amount is made larger than the feeding amount. In a wire saw cutting device that cuts an object to be cut with a wire saw,
An endless wire saw (10) formed by attaching a plurality of cutting beads (11) to a wire at a predetermined pitch;
A plurality of guide pulleys (21) for pressing the wire saw (10) against the object to be cut (30) and guiding the traveling of the wire saw (10);
A drive pulley (20) having a minimum outer diameter that allows the wire saw (10) to travel up to a maximum speed of 14 m / sec;
A drive motor (22) capable of rotating the drive pulley (20) so that the rotational torque of the drive pulley (20) is constant and maximum between a traveling speed of the wire of 3 to 14 m / sec;
Tension means (23) for applying tension to the drive pulley (20);
The directing direction of the combined vector (C1) of the pressing force vector (T1) of the cutting bead (11) and the traveling speed vector (F1) of the wire saw (10) is directed to the cutting object of the cutting bead (11). Either or both of the pressing force of the cutting beads (11) and the traveling speed of the wire saw (10) are set or adjusted while maintaining the traveling of the wire saw during cutting so as to approach the direction of the pressing force. A controller (24) to obtain;
A wire saw cutting device comprising:

Images