JP6548342B2 - Wire saw cutting method and apparatus thereof - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire saw cutting method and apparatus thereof, and more particularly to a method and apparatus capable of greatly improving cutting efficiency and shortening operation time.

  Recently, the problem of nuclear power plant decommissioning 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 jet or cutting blade are known for dismantling a building or the like, but a cutting method using a wire saw has also been proposed for dismantling buildings and dismantling power generation equipment.

  For example, a wire saw formed by attaching a plurality of super hard beads at a predetermined pitch is wound around a stainless steel heat exchanger, and while the wire saw is tensioned at 100 to 180 kgf, the wire saw is traveled at a speed of 3 to 10 m / sec. There is known a method of cutting and disassembling a stainless steel heat exchanger by causing the heat treatment (Patent Document 1), but it is expected when cutting and disassembling structures of different dimensions or structures of different materials under such setting conditions. And the need for long working hours in high radiation dose radiation controlled areas, and radiation exposure is a concern.

  On the other hand, the applicant made the shank of the cutting bead a shape having at least a part of a curved surface convexly bulging 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 a wire at a predetermined pitch is endlessly bridged between a plurality of guide pulleys and a driving pulley. We propose a technology that cuts this object by pressing this wire saw against a cutting object such as a reinforced concrete structure at such a speed that the torque of the drive motor is maximized within the range of 5 to 20 m / sec. (Patent Document 2, Patent Document 3).

  In addition, the present applicant has formed the first cutting bead in which the end surface in the feed direction is formed into a combination curved surface of the convex portion and the concave portion, and the second end surface which is opposite in the feed direction is formed into a combined curved surface shape with the convex portion and the concave portion. And an endless wire between a plurality of guide pulleys and a drive pulley, and pressing it against a cutting object such as a reinforced concrete structure. It came to propose the technique of making a saw travel at a speed within the range of 10 to 20 m / sec and cutting the object to be cut (Patent Document 4).

JP 2005-153071 A JP 2015-136853 A JP, 2015-136767, A Patent No. 583 1860

  It has been confirmed that the wire saw cutting methods described in Patent Documents 2 to 4 can shorten the working time as compared to the method described in Patent Document 1, but the cutting theory is not clear and the material of the cut is concrete or various metals In order to apply it to cutting and dismantling of nuclear power plant structures that are diverse and different in size, etc., wire saw cutting theory is analyzed in detail, appropriate conditions are established, and cutting efficiency is greatly improved It is desirable to further reduce the cutting operation time by extending the cuttable life of the wire used and also 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 cutting efficiency of the wire saw and extending the wire life.

  Therefore, in the wire saw cutting method according to the present invention, a wire saw formed by attaching a plurality of cutting beads at a predetermined pitch to a wire is endlessly bridged between a plurality of guide pulleys and a driving pulley. When pressing the wire saw against the object to be cut and traveling while rotating the wire saw around the central axis to cut the object to be cut, a convex curved surface that expands in diameter toward the front side in the traveling direction of the wire saw And using a plurality of cutting beads having a curved front edge along the direction of rotation of the wire saw, the pressing force vector of the cutting beads at the maximum load point of the cutting beads and the traveling speed vector of the wire saw So that the pointing direction of the synthesized vector approaches the optimum cutting direction vector of the cutting bead, With force and is characterized in that so as to both or to set one or adjustment of travel speed of the wire saw.

  In the wire saw cutting apparatus according to the present invention, a wire saw formed by attaching a plurality of cutting beads to a wire at a predetermined pitch is endlessly bridged between a plurality of guide pulleys and a driving pulley. In a wire saw cutting apparatus, in which the object to be cut is cut by a wire saw which is pressed while being pressed against the object to be cut and is run while rotating the wire saw around a central axis to cut the object to be cut Endless with a plurality of cutting beads attached to the wire with a predetermined pitch, which have a convex curved surface that expands toward the front side toward the rear side or has a curved front end edge along the wire saw rotation direction Wire saws, and a plurality of wire saws which are pressed against the object to be cut and which guide the traveling of the wire saws A guide pulley, a drive pulley having a minimum outer diameter that allows the wire saw to travel up to a maximum speed of 17 m / sec, a drive motor for rotationally driving the drive pulley, and tension applied to the drive pulley The drive motor is controlled so that the tension applying means and the rotational torque of the drive pulley become constant torque within the range of the wire saw traveling speed of 3 m / sec to 17 m / sec, and the maximum load of cutting beads Of the pressing force of the cutting bead and the traveling speed of the wire saw so that the pointing direction of the composite vector of the pressing force vector of the cutting bead and the traveling speed vector of the wire saw at the point approaches the optimal cutting direction vector of the cutting bead. Set any while keeping the traveling of the wire saw while cutting both or one or Characterized by comprising a controller capable of settling.

  Here, to explain the maximum load point of the cutting bead, when the object 30 to be cut has a solid rectangular cross section, the corner portion where the wire saw strongly hits as shown in FIG. 10A at the start of the cutting. The cutting bead load is the largest, and the corner is the maximum load point P. As the cutting progresses, as shown in FIG. 10 (b), the corners are cut into a gradually round shape, with which the maximum load point P gradually moves toward the center. As the cutting progresses further, as shown in FIG. 10C, the upper half of the object to be cut gradually approaches the cross-sectionally semicircular shape, and the maximum load point P moves toward the apex of the semicircular shape. That is, the maximum load point P of the cutting bead changes according to the shape of the object to be cut, and moves from the corner to the center vertex in the case of a square shape, and the center vertex is the maximum load point P in the case of a circular shape. It becomes.

  Also, in the case of a cylindrical shape, as shown in FIG. 11 (a) at the beginning of cutting, the central apex becomes the maximum load point P and as cutting progresses, the width is wide as shown in FIG. 11 (b). Moving in the direction, the corners on both sides become the maximum load point P, and after the position of the maximum lateral width, the interval between the corners, that is, the interval of the maximum load points P becomes narrow as the lateral width of the cylinder decreases.

Furthermore, in the case of a square cylindrical shape, as shown in (a) of FIG. 12 at the beginning of cutting, the load is largest at the corner where the wire saw strikes strongly, the corner becomes the maximum load point P, and cutting progresses As a result, the maximum load P spreads substantially in the lateral direction and moves to the both side walls, and the maximum load point P moves downward along the both side walls.
As described above, it is understood that the maximum load point of the cutting tip needs to be determined by the shape of the object to be cut.

  Next, we analyze the work of the wire saw. As shown in FIG. 1, the rotation speed (rpm) of the drive pulley is A, the pulling force (kgf) for the wire saw is F, the wire tension (kgf) is T, the contact length of the wire saw to the object to be cut (m) When L) and the traveling speed (m / s) of the wire saw are V, the work amount per second of the wire saw is W = F × V. F can be thought of as the sum of the forces with which the individual cutting beads in contact with the object to be cut attempt to stop the travel of the wire saw.

  Analysis of the vector representing the magnitude and direction of the force applied to the cutting bead in contact with the object to be cut when the wire is traveling: 1) Vector of component force of the force F pulling the wire saw generated by the rotation of the driving pulley ( F1), 2) vector of component force (T1) applied to each cutting bead by tension T applied to the wire, 3) vector of component force applied to the cutting object of the individual cutting bead generated by component force vector T1 (T1) P1), 4) a vector of component forces (S1) in the traveling direction of the individual cutting beads generated by the component vector T1 and a vector (C1) representing the direction and magnitude of the cutting force of the individual cutting beads The F1 + S1 vector (cutting bead travel direction) and the component force vector (P1) that individual cutting beads hold the object to be cut . This vector (C1) acts as a cutting force that each cutting bead 11 has.

  Further, in FIG. 5, cutting chips 12 generated by cutting of the individual cutting beads 11 stay on the cutting surface of the object to be cut with the progress of cutting, and this force prevents the progress of the individual cutting beads 11 (k 1 ).

  As shown in (a) to (c) of FIG. 2, when cutting chips 12 generated by cutting stay on the cutting surface of the object to be cut with the progress of cutting, the friction between the cutting chips 12 and the cutting beads 11 Also, the friction caused by the high speed travel of the cutting bead 11 generates heat 13 which results in the loss of work of the wire saw. The total weight of the wire saw is sufficiently large to ignore in view of the amount of force required to cut it. However, in the case of underwater cutting, a non-negligible resistance (M) may be added.

That is, the work of the wire saw can be roughly expressed by the following equation.
W = F × V = {(C1 × V + k1 × V) × number of beads} + frictional heat generation where F is attributable to T, and T is a synthetic force individually applied to the cutting beads in contact with the object to be cut It is approximately equal to the sum of (C1) and the force (k1) that impedes the advance of the cutting bead. 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 synthetic force (C1).

To do so, 1) eliminate stagnant cuttings to reduce k1, 2) eliminate stagnant cuttings, and smoothly rotate the cutting beads, 3) raise tension (T) to cut surfaces to concentrate the force component in the direction, 4) cutting beads individual kinetic energy because it is 1/2 · (C1 + k1) V 2, to reduce the running speed, it can be understood that it is important. In other words, if the pressing force of the cutting beads is increased, the traveling speed is decreased, cutting chips are eliminated, and the frictional heat is reduced, the energy can be dramatically converted into cutting energy.

  However, if the pressing force of the cutting bead is increased infinitely and the traveling speed is dropped to zero without limit, the direction of the composite vector of the pressing force vector of the cutting bead and the traveling speed vector of the wire saw is that of the cutting bead In order to direct the cutting object direction rather than the proper vector direction that produces efficient cutting, excessive collision of the cutting bead with the cutting object due to wire travel may occur, and in some cases, breakage of the wire or cutting bead The balance between the traveling speed V and the resultant force C1 is important because it causes excessive wear.

  In addition, the wire saw is pre-twisted and the cutting bead is rotated around the wire so that the diamond abrasive adhering to the entire circumference of the cutting bead drops off properly as the cutting progresses and maintains the cutting ability. It is already known that it is better to run while driving.

  One of the features of the present invention is that the direction of the composite of the pressing force vector of the cutting bead and the traveling speed vector of the wire saw is directed to the optimum cutting direction for the cutting object of the cutting bead. One or both of the pressing force of the cutting bead and the traveling speed of the wire saw may be set or adjusted, preferably at a point optionally set or adjusted during cutting.

  As a result, the cutting efficiency can be greatly improved and, for example, the building of the nuclear power plant can be disassembled in a short time, so that the concern of radiation exposure can be eliminated.

  In addition, the cutting method of the present invention is not limited to the dismantling of a building of a nuclear power plant, and can be applied to the dismantling of bridges, large plants, large buildings, and the like.

  Here, since the optimum cutting direction of the cutting bead differs depending on the physical property and shape of the object to be cut, it is previously determined according to the physical property and shape of the object to be cut, but the speed of cutting and the state of cutting observed during cutting By setting or adjusting the pressing force of the cutting bead and / or the traveling speed of the wire saw according to the direction of the composite vector of the pressing force vector of the bead and the traveling speed vector of the wire saw It can also be made to approach the proper (optimal) cutting direction of the beads.

  That is, the pressing force of the cutting bead against the object to be cut and / or the traveling speed of the wire saw may be arbitrarily set or adjusted while the traveling of the wire saw is maintained while cutting.

  Specifically, the optimum cutting direction vector of the cutting bead is set to be closer to the pressing force vector side so that cutting can be performed efficiently when the object to be cut is a material with high hardness such as CrMo material. In the case of a low hardness material, it is preferable to set the traveling speed vector side of the wire saw so as not to cause an excessive collision phenomenon of the cutting bead to the object to be cut. Also, when the object to be cut has a shape with a corner, the optimal cutting direction vector of the cutting bead should be closer to the traveling velocity vector side so that excessive collision of the cutting bead against the object to be cut does not occur. In order to perform cutting efficiently in the case of a shape without corners, it is preferable to set so as to approach the pressing force vector side.

  That is, the traveling speed of the wire saw is obtained by comparing the optimum cutting direction vector of the cutting bead with the optimum cutting direction vector for the cutting object of high hardness or high toughness for the cutting object of low hardness or low toughness. It is preferable to set the vector so that the optimum cutting direction vector for the cornered cutting object approaches the traveling speed vector of the wire saw as compared to the optimum cutting direction vector for the cornerless cutting object.

  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 larger the tension of the wire saw, the larger the pressing force of the cutting bead against the object to be cut. can do. However, if the tension of the wire saw is increased too much, an accident due to breakage of the wire may be concerned. Therefore, it is preferable to set the size obtained by multiplying the breaking strength of the wire saw by the safety factor as the upper limit.

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

  The traveling speed of the wire saw can be improved to the cutting energy as the speed is lower as described above, and the cutting waste adheres to the wire saw and is discharged, so it is 3 m / sec or more. If the traveling speed is 3 m / sec or more, as described above, the cutting bead excessively collides with the object to be cut by facing excessively downward than the optimum cutting direction vector of the cutting bead. This is the lower limit speed at which extreme breakage or excessive wear of the cutting bead occurs.

  When the traveling speed exceeds 17 m / sec, as shown in (d) of FIG. 2, it was found that the phenomenon in which the cutting bead 11 of the wire saw is lifted from the cut surface of the object to be cut occurs. That is, as shown in FIG. 3, the kinetic energy by the traveling of the wire saw increases with the increase of the wire speed, but when the traveling speed exceeds 17 m / sec, the thermal energy increases dramatically, but cutting It turned out that energy does not increase substantially. Therefore, it is preferable to set the traveling speed of the wire saw to a speed selected from the range of 3 m / sec to 17 m / sec.

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

  By the way, the cuttings show the behavior of the powdery fluid, and if they stay between the cutting beads and the cutting surface, the cutting beads and the staying chips will rub against each other, generating frictional heat and causing energy loss. In addition, when the amount of retained chips increases, the optimum contact of the cutting beads may be impeded, or in the worst case, the cutting beads may rise above the chips, as in the case of hydroplaning of a car running tire when it rains. Wake up. Therefore, the cutting efficiency is greatly improved, and when the cutting amount per unit time is increased, the amount of generation of cutting chips is also greatly increased, so it becomes important how to discharge the cutting chips.

  Therefore, the traveling path of the wire saw is covered with a dust collection cover, air is supplied from the near side of the wire saw movement of the dust collection cover, cutting wastes staying on the cutting surface are separated from the cutting surface, and the traveling side of the wire saw After sucking the air together with the cuttings separated from the chip and separating the cuttings with the filter, all or a part of the suctioned air is returned to the inside of the dust collection cover to be used as the feeding air. At this time, if the feed speed and suction speed of air are set higher than the traveling speed of the wire saw so that cutting chips are discharged smoothly and the suction amount of air is made larger than the feed amount, collecting The area enclosed by the dust cover is depressurized, and dust such as cuttings can be prevented from scattering around.

  Moreover, while supplying a cutting agent to a wire saw and cooling and washing a wire saw and reducing friction of cutting beads, a cutting agent can also be given using the above-mentioned feed air. Suitable amounts of water, surfactants and lubricants may be used as the cutting agent, which may be blown onto the wire saw using feed 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.
In addition, the wire saw cutting method according to the present invention may be a pull-off method as shown in FIG. 4 or may be a push-off method as shown in FIG. It is good to do.

  The abrasive for cutting of the wire saw is preferably a diamond abrasive, but it may be another super hard abrasive. The cutting abrasive can be fixed to the shank of the cutting bead by sintering, plating or brazing.

When a cylindrical cutting bead as shown in FIG. 7 is adopted as the cutting bead, the traveling speed vector is expressed by μ × m. Where μ: frictional resistance of the object to be cut, m: pressing force with which the cutting bead presses the object to be cut.
The traveling speed vector is influenced by the magnitude of the pressing force m, and the pressing force vector is mainly influenced by the tension magnitude of the wire. The magnitude of the cutting force vector is determined by the traveling speed vector and the magnitude of the pressing force vector. Therefore, the cutting amount Δt of one cutting bead is determined by the force to hold the object to be cut of the cutting bead, that is, the wire tension. The cutting amount and cutting speed of the object to be cut by the wire saw are: cutting amount == Δt × number of cutting beads, cutting speed Σt / time.

  When the pressing force is large, the force is concentrated on the front lower end portion 100 of the cutting bead, and the abrasive grains at that portion become more worn. In addition, a force (falling force) 101 which causes the cutting bead to fall in the direction of the object to be cut is generated, and the cutting bead is easily caught on the object to be cut. The abrasive grains of the lower part main part 102 of the cutting bead are affected by the overturning force 101 and cause more heat generation than cutting. In fact, since the front lower end 100 of the cutting bead is heavily worn, it is required not to raise the tension of the wire saw too much.

On the other hand, the inventor of the present invention has focused on the following points.
By setting the shape of the cutting bead to a shape that can arbitrarily set one cutting amount Δt and widen the setting range of tension, the setting range of cutting vector can be expanded, and various metal materials can be used. It is possible to set cutting vectors adapted to various physical properties up to concrete.

In addition, cutting chips are properly removed so that the abrasive grains of the cutting beads can be properly pressed against the object to be cut.
Furthermore, by increasing the number of cutting beads per meter of wire saw and lowering the traveling speed of the wire saw, the cutting amount per unit time can be increased even if the traveling speed of the wire saw is decreased, and the cutting beads Heat generation due to friction with the object to be cut is reduced, and the running energy per cutting bead is converted to cutting energy rather than heat generation, combined with the proper setting of the cutting vector and the appropriate pressing of the cutting bead mentioned above Can.

  It is important to prevent the abrasive grains on the cutting beads from being worn by contact with the side wall of the cut surface of the object to be cut, and to prevent the adhesion of impurities to the abrasive grains during metal cutting.

  Therefore, if the cutting bead has a shape as shown in FIG. 8, the abrasive grains are properly cut in any direction from the direction close to the pressing force vector to the direction close to the traveling speed vector. When the cutting vector is directed to the lower side too much, the cutting bead tends to float on the object without being caught by the object to be cut, and this action causes the cutting suitable for the physical properties of the object to be cut. A vector can be created, and thus an appropriate cutting amount Δt can be set.

  However, as shown in FIG. 8, cutting chips cut by the individual cutting beads are present in the traveling direction of the cutting beads, and the cutting chips inhibit the traveling of the wire saw and cause unnecessary wear of the abrasive grains. This causes problems such as heat generation due to friction, which will cause the generation of a proper cutting vector to be impeded. Always clean.

  By these measures, the cutting amount Δt per cutting bead can be properly set, and it is considered that the cutting speed as a whole of the wire saw in which the cutting bead is fixed continuously at a constant pitch can be improved. .

  In other words, while the present invention is based on the idea of increasing the tension of the wire saw and cutting at low speed, it can be said that the conventional method was based on the idea of lowering the tension of the wire saw and cutting at high speed. .

  In this case, if the number of cutting beads per unit meter is increased even if the traveling speed of the wire saw is reduced, the total work load as the wire saw can be increased by the number of work × cutting beads. In this point, in the conventional method, in order to increase the total work amount, the traveling speed of the wire saw has to be further increased, which is different from the problem of wire breakage and excessive heat generation.

  That is, according to the present invention, the diameter of the cutting bead is in the range of 9 to 12 mm, the length of the cutting bead is in the range of 2 to 8 mm, and the number of cutting beads per unit meter is Number of 60 or more and 250 or less, wire breaking strength of 2000 kgf, speed of wire saw within 3 to 17 m / s, cutting target per cutting bead by wire tension (T) It is possible to propose a specific condition that the average pressing force of 1.5 kgf or more.

FIG. 9 shows another example of the shape of the cutting bead used in the wire saw cutting method according to the present invention. In this example, the front end face of the cutting bead 11 in the wire saw traveling direction has a shape in which the convex end face 40a and the concave end face 40b are continuous with a smooth curved surface, and the object to be cut is the convex end face 40a. When it is cut, cutting chips are radially discharged by the concave surface 40b where the cutting edges are smoothly continued, and cutting chips are efficiently discharged. As a result, the cutting chips inhibit the running of the wire saw and waste of abrasive grains is wasted. In this case, problems such as heat generation due to friction are less likely to occur, so the cutting amount Δt per cutting bead can be properly set as in the above case, and the cutting bead has a constant pitch. Can improve the cutting speed as a whole and continuously fixed wire saw.
Although the convex end face and the concave end face are used, the cutting bead 11 has a shape having a smooth curved front end edge along the rotation direction of the wire saw 10 in consideration of the radial scraping function of the cutting chips. do it.

It is a figure for demonstrating the wire saw cutting theory which concerns on this invention. It is a figure for demonstrating the said cutting theory. It is a figure which shows the relationship between the kinetic energy of a wire, and the cutting energy and thermal energy with respect to 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 block diagram which shows the preferable embodiment of the wire saw cutting device which concerns on this 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. It is a figure for demonstrating the problem in the case of using the conventional cylindrical shaped cutting bead. It is a figure which shows the example of the shape of the bead for cutting in the wire saw cutting method which concerns on this invention. It is a figure which shows the other example of the shape of the bead for cutting in the wire saw cutting method which concerns on this invention. It is a figure for demonstrating the maximum load point of the bead for cuttings with respect to a solid square cutting object. It is a figure for demonstrating the maximum load point of the bead for cuttings with respect to a cylindrical cutting object. It is a figure for demonstrating the maximum load point of the bead for cutting with respect to a rectangular-tube cutting target object.

  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 a wire saw cutting device according to the present invention. In the figure, the wire saw 10 has, for example, an interval of 60 to 250 pieces / m for the bead diameter of φ10 mm (φ9 to 13 mm) and shank length 8 mm (2 to 8 mm) with a breaking strength of 2000 kgf wire. The cutting bead 11 is formed in a convex curved surface such that the outer diameter gradually increases from the front side to the rear side in the traveling direction of the wire saw 10.

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

  A drive shaft of a drive motor 22 such as a servomotor which generates a constant rotational torque in a wide range of rotation range is connected to the drive pulley 20 directly or through a reduction gear group, and a tension mechanism 23 is a shock absorber for the drive pulley 20. 32 and the drive motor 22 and the pulling mechanism 23 have a tension within the range of 1000 kgf or less of the wire saw 10, whereby the pressing force of one cutting bead 11 is as large as 1.5 kgf or more. Also, the controller 24 controls the traveling speed of the wire saw 10 to be a speed selected from the range of 3 m / sec to 17 m / sec.

  The controller 24 has a function to detect and display the tension of the wire saw 10 and the traveling speed of the wire saw 10, and the operator operates the knob while viewing the tension and the traveling speed during the cutting operation. The control signal to 22 and the pulling mechanism 23 is given to change the torque of the drive motor 22 and the tension of the wire saw 10. The shock absorbing device 32 prevents the pulling force T of the drive pulley 20 from pulsating due to the traveling of the wire, and is controlled so as to be maintained substantially constant at a predetermined pulling force.

Further, the object to be cut 20 is provided with a dust collection cover 25 to cover the traveling path of the wire saw 10, and the dust collection cover 25 has a feed port 28 for feeding air into the dust collection cover 25. The suction port 26 for suctioning the air in the dust collection cover 25 is formed on the traveling side of the wire saw 10, and the suction port 26 is provided with a dust removing device 27 such as a bag filter. A portion of the air afterward is returned to the feed port 28.
Here, the feeding speed of air from the feeding port 28 and the suction speed of air from the suction port 26 are set to be higher than the traveling speed of the wire saw 10, and the suction quantity of air is higher than the feeding quantity of air. It is set to be more.

  Now, as shown in FIG. 5, assuming that the composite 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 F1 + S1 to F1 'to F1' + S1. The resultant vector C1 'approaches the direction of the pressing force. In addition, when the pressing force of the cutting bead 11 is increased, the combined vector can be brought closer to the direction of the pressing force.

Therefore, air is fed from the feed port 28 into the dust collection cover 25 and suctioned from the suction port 26 to discharge the cuttings 12, and at the same time, the controller 24 reduces the rotational speed of the drive motor 22. Also, the cutting object 30 can be efficiently cut in a short time by controlling the tension T of the pulling mechanism 23 to be large, and the cutting beads are sequentially discharged from the cutting surface 12 Smoothly rotated, the bead wear was eliminated, and the bead wear due to cutting chips was also reduced, and the cutting life of the cutting bead was also extended.
According to the experiments of the present inventors, a 1 m x 1 m concrete block with 30 mm diameter x 10 bars arranged is cut at a wire tension of 100 kg and a traveling speed of 9 m / s of the wire saw 10, 15 minutes It has been confirmed that dry cutting is possible.

FIG. 6 shows a second embodiment, in which the same reference numerals as 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 pulleys 20, and it is also possible to cut in this way by the push-off method.
According to the experiments of the present inventors, when a block of 30 cm × 30 cm of carbon steel for machine structure S35C was cut, it was confirmed that the cutting can be performed in 25 minutes. In the case of a metal material, the heat generation is increased, so it is preferable to spray the cooling water by the nozzle 29.

DESCRIPTION OF SYMBOLS 10 wire saw 11 bead for cutting 12 cutting waste 20 drive pulley 21 guide pulley 22 drive motor 23 pulling mechanism 24 controller 30 cutting object

Claims (6)

A wire saw obtained by attaching a plurality of cutting beads to a wire at a predetermined pitch is endlessly bridged between a plurality of guide pulleys and a driving pulley, and the wire saw is pressed against the object to be cut. When traveling while cutting around the axis while cutting around the axis,
For cuttings that have a convexly curved surface that increases in diameter toward the rear in the direction of travel of the wire saw (10) or has a curved front edge along the direction of rotation of the wire saw (10) Directing the composite vector (C1) of the pressing force vector (T1) of the cutting bead (11) and the traveling speed vector (F1) of the wire saw at the maximum load point of the cutting bead (11) using the bead (11) The pressing force of the cutting bead (11) against the cutting object and / or the traveling speed of the wire saw (10) are set so that the direction approaches the optimum cutting direction of the cutting bead (11) for the cutting object While setting or adjusting,
The diameter of the cutting bead (11) is in the range of 9 to 12 mm, the length of the cutting bead (11) is in the range of 2 to 8 mm, the number of cutting beads (11) per unit meter Number of 60 or more and 250 or less, wire breaking strength of 2000 kgf, speed of wire saw (10) within 3 to 17 m / s, bead for cutting by wire tension (T) (11) 1 A wire saw cutting method characterized in that an average pressing force on an object to be cut per piece is 1.5 kgf or more. The wire saw runs with the optimum cutting direction of the cutting bead (11) compared to the optimum cutting direction for the high hardness or high toughness cutting object for the low hardness or low toughness cutting object The cutting direction of the wire saw approaches the direction in which the velocity vector (F1) is directed , and the optimum cutting direction for the cutting object with the corners is compared with the optimum cutting direction for the cutting object without the corners . The wire saw cutting method according to claim 1, wherein the wire saw is set to approach a pointing direction .   To set or adjust arbitrarily while keeping the traveling of the wire saw (10) while cutting the pressing force of the cutting bead (11) against the cutting object and / or the traveling speed of the wire saw (10) The wire saw cutting method according to claim 1.   When cutting a metal cutting object, the traveling speed of the wire saw (10) is 10 m / sec or less, and the average per one cutting object of cutting beads (11) of the wire saw (10) The wire saw cutting method according to claim 1, wherein the pressing force is 3 kgf or more.   When cutting a concrete cutting object, the traveling speed of the wire saw (10) is 14 m / sec or less, and the average per cutting object of the cutting bead (11) of the wire saw (10) The wire saw cutting method according to claim 1, wherein the pressing force is 1.5 kgf or more. Cover the traveling path of the wire saw (10) in the object to be cut with a dust collection cover (25), suction air from the traveling side of the wire saw (10) of the dust collection cover (25) some feeds feeding air to the dust collection cover (25) back to the wire saw (10) running front side, the speed of the air is faster than the traveling speed of the wire saw (10), feeding the amount of suction air The wire saw cutting method according to claim 1, wherein the wire saw is made to be larger than a supply amount.

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