Circular saw cutting machine

Abstract

To provide a circular saw cutting machine that can stably cut the material to be cut and shorten the cutting time. [Solution] The circular saw cutting machine 10 includes a sampling cutting control unit 82 that performs sampling cutting SC, which involves rotating the circular saw 24 at a predetermined rotational speed Nn and moving it in the cutting direction f at a predetermined movement speed Vn to cut the material to be cut 14, and detecting the cutting start position P1, the cutting end position P2, and the maximum load power Emax, which is the maximum value of the load power E of the circular saw rotation drive device 26; and an FB cutting control unit 84 that performs FB cutting FC, which involves changing the movement speed V of the circular saw between the cutting start position P1 and the cutting end position P2 from a predetermined movement speed Vn to a variable movement speed Vv at predetermined cycles t, with the predetermined movement speed Vn as the lower limit and the cutting load FB value Efb as the size of the cutting load FB value Efb, to cut the material to be cut 14.

Description

Technical Field

[0001] The present invention relates to a circular saw cutting machine for shortening the cutting time of a workpiece to be cut.

Background Art

[0002] In a circular saw cutting machine including a disk-shaped circular saw having a plurality of outer peripheral blades arranged in the circumferential direction, a circular saw rotation driving device including an electric motor for rotationally driving the circular saw, and a circular saw moving device for moving the circular saw in the cutting direction to cut into a metal workpiece to be cut, a circular saw cutting machine is known that detects the load current of the electric motor during cutting of the circular saw rotation driving device, that is, the load of the electric motor in cutting, and controls the moving speed (feed speed) of the circular saw to be cut into the workpiece to be cut based on the detected value. For example, the cutting machine described in Patent Document 1 is such. This Patent Document 1 discloses a technique for performing cutting by controlling the moving speed (feed speed) of the circular saw so that the load current of the electric motor becomes a reference load current that is optimal for cutting implementation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the control of the cutting machine described in the above-mentioned Patent Document 1 performs stable cutting by keeping the load of the electric motor in cutting constant by the reference load current. However, the combinations of the type, shape of the workpiece to be cut, and the circular saw are enormous, and an optimal reference load current corresponding to each variation in individual differences must be set. If it is difficult to set the optimal reference load current, the control of the moving speed (feed speed) of the circular saw cannot be appropriately performed, and there is a risk that the cutting time will become long.

[0005] This invention was made against the above circumstances, and its objective is to provide a circular saw cutting machine that can stably cut the material to be cut and shorten the cutting time. [Means for solving the problem]

[0006] The gist of the first invention is a circular saw cutting machine that cuts a workpiece by controlling the circular saw rotation drive device and the circular saw moving device, comprising: (a) a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base plate; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal workpiece, wherein the circular saw cutting machine cuts the workpiece by rotating the circular saw at a predetermined rotation speed and moving it in the cutting direction at a predetermined moving speed, and the cutting start position of the circular saw where the outer blades begin to cut into the workpiece, the cutting end position of the circular saw where the cutting state of the outer blades into the workpiece is released, and the circular saw rotation drive device Detected during cutting at the predetermined travel speed and the predetermined rotation speed. (c) In cutting the material to be cut after the sampling cut, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined speed in the cutting direction, and the speed of the circular saw between the cutting start position and the cutting end position is set at predetermined intervals to the maximum load power and Detected during cutting at the predetermined rotational speed (d) A feedback cutting control unit that performs feedback cutting by changing the predetermined moving speed to a variable moving speed in accordance with a cutting load feedback value calculated based on the load power, and cuts the material to be cut, is included, The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut, (e) The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit.

[0007] The gist of the second invention is a circular saw cutting machine that cuts a workpiece by controlling the circular saw rotation drive device and the circular saw moving device, comprising: (a) a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base plate; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal workpiece, wherein the circular saw cutting machine cuts the workpiece by rotating the circular saw at a predetermined rotation speed and moving it in the cutting direction at a predetermined moving speed, and the cutting start position of the circular saw where the outer blades begin to cut into the workpiece, the cutting end position of the circular saw where the cutting state of the outer blades into the workpiece is released, and the circular saw rotation drive device Detected during cutting at the predetermined travel speed and the predetermined rotation speed. (c) In cutting the material to be cut after the sampling cut, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined speed in the cutting direction, and the speed of the circular saw between the cutting start position and the cutting end position is set from the predetermined speed to the maximum load power at predetermined intervals. Detected during cutting at the predetermined rotational speed (d) A feedback cutting control unit that performs feedback cutting by varying the moving speed according to a variable value calculated based on the load power and the cutting load feedback value, and cuts the material to be cut, is included, The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut, (e) The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. (f) The cutting load feedback value is calculated as the value obtained by dividing the maximum load power by the load power, and the variable travel speed is the value obtained by multiplying the cutting load feedback value by the predetermined travel speed.

[0008] The gist of the third invention is a circular saw cutting machine that cuts a workpiece by controlling the circular saw rotation drive device and the circular saw moving device, comprising: (a) a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal workpiece, wherein the circular saw cutting machine cuts the workpiece by rotating the circular saw at a predetermined rotation speed and moving it in the cutting direction at a predetermined moving speed, and the cutting start position of the circular saw where the outer blades begin to cut into the workpiece, the cutting end position of the circular saw where the cutting state of the outer blades into the workpiece is released, and the circular saw rotation drive device Detected during cutting at the predetermined travel speed and the predetermined rotation speed. (c) In cutting the material to be cut after the sampling cut, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined speed in the cutting direction, and the speed of the circular saw between the cutting start position and the cutting end position is set from the predetermined speed to the maximum load power at predetermined intervals. Detected during cutting at the predetermined rotational speed (d) A feedback cutting control unit that performs feedback cutting by varying the moving speed according to a variable value calculated based on the load power and the cutting load feedback value, and cuts the material to be cut, is included, The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut, (e) The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. (g) In the feedback cutting described above, if the circular saw is located between the cutting start position and a position a predetermined distance from the cutting start position in the cutting direction, and between the cutting end position and a position a predetermined distance back in the opposite direction from the cutting end position in the cutting direction, the movement speed of the circular saw is set to the predetermined movement speed.

[0010] The gist of the fourth invention is a circular saw cutting machine that cuts a workpiece by controlling the circular saw rotation drive device and the circular saw moving device, comprising: (a) a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal workpiece, wherein the circular saw cutting machine cuts the workpiece by rotating the circular saw at a predetermined rotation speed and moving it in the cutting direction at a predetermined moving speed, and the cutting start position of the circular saw where the outer blades begin to cut into the workpiece, the cutting end position of the circular saw where the cutting state of the outer blades into the workpiece is released, and the circular saw rotation drive device Detected during cutting at the predetermined travel speed and the predetermined rotation speed. (c) In cutting the material to be cut after the sampling cut, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined speed in the cutting direction, and the speed of the circular saw between the cutting start position and the cutting end position is set from the predetermined speed to the maximum load power at predetermined intervals. Detected during cutting at the predetermined rotational speed (d) A feedback cutting control unit that performs feedback cutting by varying the moving speed according to a variable value calculated based on the load power and the cutting load feedback value, and cuts the material to be cut, is included, The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut, (e) The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. (h) The circular saw cutting machine is equipped with a load stop function that stops the machine when the load power exceeds a predetermined upper limit power, and the predetermined upper limit power is set by the sampling cutting control unit based on the maximum load power. Furthermore, the gist of the fifth invention is that, in any one of the first to fourth inventions, the sampling cut is performed when at least one of the following occurs: the material to be cut is replaced, the cutting conditions are changed, or the circular saw cutting machine is restarted from a start or stop. [Effects of the Invention]

[0011] According to the circular saw cutting machine of the first invention, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined movement speed in the cutting direction to cut the material to be cut, and the cutting start position of the circular saw is where the outer blade begins to cut into the material to be cut, the cutting end position of the circular saw is where the cutting state of the outer blade into the material to be cut is released, and the circular saw rotation drive device Detected during cutting at the predetermined travel speed and the predetermined rotation speed. A sampling cutting control unit performs sampling cutting to detect the maximum load power, which is the maximum value of the load power, and in cutting the material to be cut after the sampling cutting, the circular saw is rotated at a predetermined rotational speed and moved at a predetermined speed in the cutting direction, and the speed of the circular saw between the cutting start position and the cutting end position is set from the predetermined speed at predetermined intervals to the maximum load power and Detected during cutting at the predetermined rotational speed It includes a feedback cutting control unit that performs feedback cutting, which cuts the material to be cut by varying the moving speed according to a variable speed corresponding to a cutting load feedback value calculated based on the load power, The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut. The variable movement speed is set to be greater than the predetermined movement speed as the cutting load feedback value increases, with the predetermined movement speed being the lower limit. Thus, in the feedback cutting, the variable movement speed is set to be greater than the predetermined movement speed at which the material to be cut is stably cut, with the cutting load feedback value being greater as the cutting load on the material to be cut increases. The aforementioned The smaller the load compared to the maximum load state, the greater the speed is set to exceed the predetermined travel speed. Therefore, the material to be cut is cut stably and the cutting time is shortened. In addition, the amount of chips generated from the material being cut and jammed during cutting is reduced, which is expected to improve the lifespan of the circular saw.

[0012] According to the circular saw cutting machine of the second invention, the cutting load feedback value is calculated as the value obtained by dividing the maximum load power by the load power, and the variable travel speed is the value obtained by multiplying the cutting load feedback value by the predetermined travel speed. Thus, in the feedback cutting, the variable travel speed is calculated using a simple calculation formula such that the lower limit is the predetermined travel speed at which the material to be cut can be stably cut, and the larger the cutting load feedback value is, that is, the smaller the cutting load of the material to be cut is compared to the maximum load state, the greater the variable travel speed is than the predetermined travel speed.

[0013] According to the circular saw cutting machine of the third invention, in the feedback cutting, when the circular saw is located between the cutting start position and a position a predetermined distance from the cutting start position in the cutting direction, and between the cutting end position and a position a predetermined distance back in the opposite direction from the cutting end position, the movement speed of the circular saw is set to the predetermined movement speed. As a result, when the number of teeth of the outer blade that cut into the material to be cut is small, the variable movement speed is set to the predetermined movement speed, thereby suppressing chipping of the outer blade.

[0015] The 4 The circular saw cutting machine of the invention is equipped with a load stop function that stops the circular saw cutting machine when the load power exceeds a predetermined upper limit power, and the predetermined upper limit power is set by the sampling cutting control unit based on the maximum load power. As a result, the predetermined upper limit power is automatically set by the sampling cutting control unit during sampling cutting, eliminating the need for manual setting. According to the circular saw cutting machine of the fifth invention, the sampling cutting is performed when at least one of the following conditions is met: the material to be cut is replaced, the cutting conditions are changed, or the circular saw cutting machine is started or restarted from a stopped state. This allows the feedback cutting to be performed in an appropriate response to variations in the material to be cut, wear of the outer blade, changes in cutting conditions, and the starting or restarting of the circular saw cutting machine. [Brief explanation of the drawing]

[0016] [Figure 1] This figure illustrates the main components of a circular saw cutting machine according to one embodiment of the present invention. [Figure 2] This is a magnified view of a portion of the circular saw in Figure 1. [Figure 3]It is a flowchart for explaining an example of the control operation of sampling cutting performed by the sampling cutting control unit included in the electronic control device of FIG. 1. [Figure 4] It is a diagram for explaining the transition of the moving speed of the circular saw and the load power of the electric motor in sampling cutting, and is a diagram corresponding to the flowchart of FIG. 3. [Figure 5] It is a flowchart for explaining an example of the control operation of feedback cutting performed by the feedback cutting control unit included in the electronic control device of FIG. 1. [Figure 6] It is a diagram for explaining the transition of the moving speed of the circular saw and the load power of the electric motor in feedback cutting, and is a diagram corresponding to the flowchart of FIG. 5. [Figure 7] It is a diagram for explaining the difference in the measurement results depending on whether feedback cutting is performed or not regarding the cutting time required for cutting the workpiece to be cut. [Figure 8] It is a diagram for explaining the difference in the test results depending on whether feedback cutting is performed or not regarding the life of the circular saw.

Mode for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or deformed, and the dimensional ratios and shapes of each part are not necessarily drawn accurately.

Embodiment

[0018] Figure 1 is a diagram illustrating the main parts of a swing-type circular saw cutting machine 10 according to one embodiment of the present invention. In Figure 1, the circular saw cutting machine 10 includes a material feed device 16 that feeds the material to be cut 14, supplied from a material feeding device (not shown) located on the back side of the circular saw cutting machine 10 shown in Figure 1, intermittently in the longitudinal direction by a predetermined predetermined dimension for each cut, that is, moves it in a direction parallel to the axis O1 of the material to be cut 14; a disc-shaped circular saw 24 that is rotatable around a rotation center C2 at the upper end of a tilting member 22 whose lower end is rotatable around a rotation center C1 by a support base 20 via a support shaft 18; a circular saw rotation drive device 26 that continuously rotates the circular saw 24; and a circular saw moving device 28 that moves the circular saw 24 toward the material to be cut 14 in order to cut into the metal material to be cut 14. In Figure 1, the material to be cut 14 is a round metal rod, arranged so as to have a longitudinal shape perpendicular to the plane of the paper. Note that the material to be cut 14 is not limited to a round rod shape and may have various cross-sectional shapes.

[0019] The above-mentioned material length-adjustable feeding device 16 comprises a work table 30 on which the material to be cut 14 is placed, a movable clamping device (not shown) that clamps the material to be cut 14 and moves it by a predetermined distance in a direction parallel to its axis O1, and a horizontal clamping device 32 and a vertical clamping device 34 that fix the position of the material to be cut 14 on the work table 30.

[0020] The horizontal clamping device 32 includes a hydraulic cylinder (not shown) having a piston that can reciprocate in a direction perpendicular to the axis O1 of the material to be cut and parallel to the upper surface (workpiece mounting surface) of the work table 30, i.e., in the direction of arrow a in Figure 1, and a clamping pad 38 fixed to the tip of a movable member 36 connected to the piston rod of the hydraulic cylinder and movable in the direction of arrow a. The horizontal clamping device 32 fixes the material to be cut 14 by clamping it between the clamping pad 38 and the backing plate 40 by operating the hydraulic cylinder to advance the clamping pad 38 toward the material to be cut 14. The backing plate 40 is fixedly positioned on the work table 30 on the opposite side of the material to be cut 14 from the clamping pad 38. The horizontal clamping device 32 releases the fixing of the material to be cut 14 when the material to be cut 14 is moved by the movable clamping device.

[0021] The vertical clamping device 34 includes a hydraulic cylinder 42 having a piston that can reciprocate in a direction perpendicular to the axis O1 of the material to be cut 14 and perpendicular to the upper surface of the work table 30 (the surface on which the material to be cut 14 is placed), i.e., in the direction of arrow b in Figure 1, on the side of the material to be cut 14 away from the work table 30, and a clamping pad 44 fixed to the tip of the piston rod of the hydraulic cylinder 42. The vertical clamping device 34 fixes the material to be cut 14 by clamping it between the clamping pad 44 and the work table 30 by operating the hydraulic cylinder 42 to advance the clamping pad 44 toward the material to be cut 14. The vertical clamping device 34 releases the fixing of the material to be cut 14 when the material to be cut 14 is moved by the movable clamping device. Fixing the material to be cut 14 by the vertical clamping device 34 is preferably performed after fixing the material to be cut 14 by the horizontal clamping device 32.

[0022] Figure 2 is an enlarged view of a part of the circular saw 24 shown in Figure 1. As shown in Figure 2, the circular saw 24 comprises a disc-shaped base plate 46 and a plurality of carbide tips 48 that are connected at regular intervals in the circumferential direction on the outer circumference of the base plate 46 and fixed to the base plate 46 by means of, for example, brazing. The carbide tips 48 constitute a plurality of outer blades of the circular saw 24 and correspond to the "outer blades" of the present invention. As shown in Figure 1, the base plate 46 is integrally fixed to a rotating shaft 50 and is supported by a tilting member 22 via the rotating shaft 50 so as to be rotatable around a rotation center C2. L in Figure 2 shows the rotational trajectory of the blade portion formed on the carbide tip 48 of the circular saw 24. Note that in Figure 1, the circular saw cover 52 that covers the circular saw 24 is shown partially cut out.

[0023] Returning to Figure 1, the circular saw rotation drive device 26 includes a rotating shaft 50 that rotatably supports the circular saw 24 around a rotation center C2, a circular saw drive motor 54 as a power source for rotationally driving the circular saw 24, and transmission members (not shown), such as pulleys and belts, for transmitting the rotation of the output shaft of the circular saw drive motor 54 to the rotating shaft 50. The circular saw drive motor 54 is fixed to the tilting member 22. The circular saw rotation drive device 26 rotates the circular saw 24 in the direction of arrow c by operating the circular saw drive motor 54 and transmitting the rotation of its output shaft to the rotating shaft 50 via the transmission members. The circular saw drive motor 54 is a so-called rotating electric machine driven by, for example, three-phase AC, and is controlled by the electronic control device 80 described later. The circular saw drive motor 54 corresponds to the "electric motor" of the present invention.

[0024] The circular saw moving device 28 drives a first support member 58, which is fixed to the upper surface of a machine base 56 integrated with a work table 30 that holds the workpiece 14, and a second support member 60, which is fixed to the upper part of a tilting member 22 that supports the circular saw 24, to move the circular saw 24 toward the workpiece 14 or toward the opposite side of the workpiece 14, so as to move them toward and away from each other. Specifically, the circular saw moving device 28 includes a hollow cylindrical support member 62 rotatably supported by a first support member 58 around a pivot center C3, an electrically driven servo motor 64 fixed to the end of the support member 62 opposite to the second support member 60 and having a ball screw-shaped rotation output shaft substantially concentric with the axis of the support member 62, and a cylindrical axial moving member 66, one end of which is screwed onto the outer circumference of the ball screw rotation output shaft and supported by the inner circumferential surface of the support member 62 so as to be movable in the axial direction but not rotatable around the axis, and the other end of which is supported by the second support member 60 so as to be rotatable around a pivot center C4 parallel to the pivot center C3. The circular saw moving device 28 tilts the tilting member 22 in the direction of arrow e in Figure 1 by operating the servo motor 64 and moving the axial moving member 66, which is connected to the upper part of the tilting member 22 via the second support member 60, in its axial direction, i.e., in the direction of arrow d in Figure 1. The servo motor 64 is controlled by the electronic control unit 80, which will be described later.

[0025] In cutting the material to be cut 14, first, the material to be cut 14 is supplied onto the work table 30 from a material feeding device (not shown) by a material fixed-length feeding device 16. Next, the material to be cut 14 is clamped and fixed by a horizontal clamping device 32 and a vertical clamping device 34. Then, the circular saw 24 is rotated at a predetermined rotational speed Nn [rpm] by a circular saw rotation drive device 26 (electric motor for circular saw drive 54). The predetermined rotational speed Nn is a set value determined in advance to ensure stable cutting even under the maximum load conditions of cutting the material to be cut 14, for example. Next, the circular saw 24 is moved from the standby position in the pre-cutting state shown in Figure 1 (hereinafter referred to as the home position P0) in the cutting direction f by a circular saw moving device 28 (servo motor 64) at a moving speed V [mm / min], and cutting is performed by cutting into the material to be cut 14. The cutting operation of the material to be cut 14 is performed by sampling cutting SC or feedback cutting (hereinafter referred to as FB cutting) FC, which will be described later. After the material to be cut 14 is cut, the circular saw 24 is returned to the home position P0 by the circular saw moving device 28 (servo motor 64), and thereafter the operation of supplying the material to be cut 14 onto the work table 30 is repeated.

[0026] The circular saw cutting machine 10 is equipped with an electronic control device 80 that controls the circular saw rotation drive device 26 (electric motor 54 for driving the circular saw) and the circular saw movement device 28 (servo motor 64). The electronic control device 80 includes a so-called microcomputer, and input signals are processed according to a pre-stored program. The electronic control device 80 may be configured identically to the control devices described above, such as the material length feeding device 16, the horizontal clamping device 32, and the vertical clamping device 34.

[0027] The electronic control unit 80 is supplied with various signals based on values ​​detected by various sensors (for example, the circular saw rotation speed sensor 90, the circular saw drive motor load power sensor 92, the servo motor 64, etc.) provided in the circular saw rotation drive unit 26 and the circular saw movement unit 28. These signals include, for example, the rotation speed N [rpm] of the circular saw 24, the load power E [kW] of the circular saw drive motor 54, and the movement position P [mm], which is the distance traveled by the circular saw 24 from its home position P0 and indicates its current position.

[0028] The electronic control unit 80 outputs an MG control command signal Smg to the electric motor 54 for driving the circular saw, which controls the rotational speed N of the circular saw 24, and a servo control command signal Ssv to the servo motor 64, which controls the movement position P and movement speed V of the circular saw 24.

[0029] The electronic control unit 80 functionally includes a sampling cutting control unit 82 that controls the sampling cutting SC, and a feedback cutting control unit (hereinafter referred to as the FB cutting control unit) 84 that controls the FB cutting FC.

[0030] Figure 3 is a flowchart illustrating an example of the control operation of the sampling cutting control unit 82 for the sampling cutting SC. The sampling cutting SC is performed by parallel processing of the cutting position detection routine in Figure 3(a) and the maximum load detection routine in Figure 3(b). Figure 4 is a diagram illustrating the changes in the movement speed V and load power E during the sampling cutting SC. The horizontal axis represents the movement position P, the upper vertical axis shows the movement speed V, and the lower vertical axis shows the load power E. Hereafter, the control operation of the sampling cutting control unit 82 will be explained in accordance with the processing steps of each routine in Figure 3, with reference to Figure 4.

[0031] The cutting position detection routine in Figure 3(a) and the maximum load detection routine in Figure 3(b) are activated, for example, when the material to be cut 14 is clamped by the horizontal clamping device 32 and the vertical clamping device 34, and the circular saw 24 is rotated at a predetermined rotational speed Nn by the circular saw rotation drive device 26 (circular saw drive motor 54), and are executed in parallel. First, in step S1 of the cutting position detection routine in Figure 3(a) (steps omitted hereafter), the circular saw 24 starts moving in the cutting direction f at a predetermined movement speed Vn. That is, a servo control command signal Ssv is output to the servo motor 64 so that the circular saw 24 moves from the home position P0 in the cutting direction f at a predetermined movement speed Vn. In Figure 4, the transition at the home position P0 corresponds to the processing in S1. The predetermined movement speed Vn is a predetermined setting value that can stably cut even under the maximum load conditions of cutting the material to be cut 14, depending on the material to be cut 14.

[0032] Next, in S2, it is determined whether or not the start of cutting is detected, that is, whether or not the carbide tip 48 of the circular saw 24 has started to cut into the workpiece 14. The determination of the detection of the start of cutting is performed, for example, based on whether or not the fluctuation width ΔE from the no-load (non-cutting) load power E1 of the load power E of the electric motor 54 for driving the circular saw is equal to or greater than a predetermined power Ecn. In FIG. 4, when the load power E rises to E2 and the cutting start is detected at the moving position P1 where ΔE = E2 - E1 ≧ Ecn. If the determination in S2 is negative, the determination in S2 is repeated.

[0033] If the determination in S2 is affirmative, in S3, P1, which is the moving position where the start of cutting is detected in S2, is stored as the cutting start position P1.

[0034] Next, in S4, it is determined whether or not the end of cutting is detected, that is, whether or not the cutting state of the carbide tip 48 of the circular saw 24 into the workpiece 14 has been eliminated. The determination of the detection of the end of cutting is performed, for example, based on whether or not the fluctuation width ΔE from the load power E1 of the load power E of the electric motor 54 for driving the circular saw is smaller than a predetermined power Ecn. In FIG. 4, when the load power E drops to E2 and the end of cutting is detected at the moving position P2 where ΔE = E2 - E1 < Ecn. If the determination in S4 is negative, the determination in S4 is repeated.

[0035] If the determination in S4 is affirmative, in S5, P2, which is the moving position where the end of cutting is detected in S4, is stored as the cutting end position P2, and in S6, the servo control command signal Ssv is output to the servo motor 64 so that the movement of the circular saw 24 stops, that is, the movement speed V becomes 0, and this routine is terminated. In FIG. 4, the transition at the cutting end position P2 corresponds to the processing of S5 and S6. By this routine (cutting position detection routine), the workpiece 14 is cut, and the cutting start position P1 and the cutting end position P2 are detected.

[0036] The predetermined power Ecn is a threshold value that has been determined and set in advance through design or experimentation so that the start and end of cutting of the material to be cut 14, i.e., the start and end of the cut made by the carbide tip 48 into the material to be cut 14, can be suitably detected by the fluctuation range of the load power E.

[0037] Next, the processing steps of the maximum load detection routine in Figure 3(b) will be explained. First, in S10, it is determined whether or not the start of disconnection has been detected. The determination of whether the start of disconnection has been detected is performed, for example, in the same way as the determination in S2 in Figure 3(a), or by referring to a flag that updates and reflects the determination result of S2. If the determination in S10 is negative, the determination in S10 is repeated.

[0038] If the judgment in S10 is affirmative, in S20 the maximum value of the load power E, i.e., the maximum load power Emax, is updated and stored.

[0039] Next, in S30, it is determined whether the movement of the circular saw 24 has stopped, i.e., whether the movement speed V has become 0. If the determination in S30 is negative, the process transitions to S20 and the processing of S20 is repeated. If the determination in S30 is positive, this routine is terminated. This routine (maximum load power detection routine) detects the maximum load power Emax shown in Figure 4.

[0040] In this manner, the sampling cutting control unit 82 rotates the circular saw 24 at a predetermined rotational speed Nn and moves it in the cutting direction f at a predetermined movement speed Vn to cut the material to be cut 14, while simultaneously performing a sampling cutting SC that detects the cutting start position P1, the cutting end position P2, and the maximum load power Emax.

[0041] The FB cutting control unit 84 performs FB cutting FC in which, when cutting the material to be cut 14 after sampling cutting SC, it rotates the circular saw 24 at a predetermined rotational speed Nn and moves it in the cutting direction f at a predetermined movement speed Vn, and changes the movement speed V of the circular saw 24 between the cutting start position P1 and the cutting end position P2 from the predetermined movement speed Vn to a variable movement speed Vv corresponding to the cutting load feedback value (hereinafter referred to as the cutting load FB value) Efb calculated at predetermined cycles t based on the maximum load power Emax and load power E, thereby cutting the material to be cut 14.

[0042] Figure 5 is a flowchart illustrating an example of the control operation of the FB cutting FC performed by the FB cutting control unit 84. Figure 6 is a diagram illustrating the changes in the movement speed V and load power E in the FB cutting FC. Similar to Figure 4, the horizontal axis represents the movement position P, the upper part of the vertical axis represents the movement speed V, and the lower part of the vertical axis represents the load power E. Hereafter, the control operation of the FB cutting control unit 84 will be explained following the processing steps in Figure 5, with reference to Figure 6.

[0043] The flowchart in Figure 5 is executed, for example, when cutting the material to be cut 14 after sampling cut SC, the material to be cut 14 is clamped by the horizontal clamping device 32 and the vertical clamping device 34, and the circular saw 24 is rotated at a predetermined rotational speed Nn by the circular saw rotation drive device 26 (electric motor for circular saw drive 54). First, in step (steps omitted below) S100, the circular saw 24 starts moving in the cutting direction f at a predetermined movement speed Vn. That is, similar to S1 in Figure 3, a servo control command signal Ssv is output to the servo motor 64 so that the circular saw 24 moves from the home position P0 in the cutting direction f at a predetermined movement speed Vn. In Figure 6, the transition at the home position P0 corresponds to the processing in S100.

[0044] Next, it is determined whether the circular saw 24 has moved to the variable speed start position P11 in S200. This determination is made, for example, by checking whether the moved position P is greater than or equal to the variable speed start position P11 (P≧P11). Here, the variable speed start position P11 is given as a position obtained by advancing a predetermined distance S in the cutting direction f from the cutting start position P1 (P11=P1+S), and if the predetermined distance S is 0, the variable speed start position P11 becomes the cutting start position P1. If the determination in S200 is denied, the determination in S200 is repeated.

[0045] If the determination in S200 is affirmative, in S300 the load power E is detected, and then in S400 the cutting load FB value Efb is calculated, and the variable movement speed Vv corresponding to the calculated cutting load FB value Efb is calculated, and a servo control command signal Ssv is output to the servo motor 64 so that the movement speed V becomes the variable movement speed Vv. The cutting load FB value Efb is calculated, for example, by applying the maximum load power Emax and the load power E to a pre-prepared map or calculation formula. The variable movement speed Vv is calculated based on a pre-prepared map or calculation formula, with a predetermined movement speed Vn as the lower limit, such that the greater the cutting load FB value Efb, the greater the movement speed Vv becomes than the predetermined movement speed Vn.

[0046] Preferably, the cutting load FB value Efb is calculated as the value obtained by dividing the maximum load power Emax by the load power E detected in S300, and the variable travel speed Vv is calculated as the value obtained by multiplying the cutting load FB value Efb by a predetermined travel speed Vn. That is, the variable travel speed Vv is calculated by the following equation (1), and according to the following equation (1), the variable travel speed Vv is calculated such that, with the predetermined travel speed Vn as the lower limit, the larger the cutting load FB value Efb is, the greater the variable travel speed Vv is than the predetermined travel speed Vn. Vv=Efb×Vn=(Emax / E)×Vn (1)

[0047] Next, in S500, it is determined whether a predetermined period t has elapsed since the processing in S400. If the determination in S500 is affirmative, the process proceeds to S300, and the processing from S300 onward is repeatedly executed. In Figure 6, the transition from the variable speed start position P11 to the variable speed end position P12, described later, corresponds to the above repeated execution. The predetermined period t is a sampling period that is set in advance so as to suitably reflect the variable movement speed Vv.

[0048] If the judgment in S500 is denied, in S600, it is determined whether the circular saw 24 has moved to the variable speed end position P12. This determination is made, for example, whether the moved position P is greater than or equal to the variable speed end position P12 (P≧P12). Here, the variable speed end position P12 is given as a position (P12=P1-S) that is returned a predetermined distance S in the opposite direction to the cutting direction f from the cutting end position P2. If the predetermined distance S is 0, the variable speed end position P12 becomes the cutting end position P2. If the judgment in S600 is denied, the process proceeds to S500, and the processing from S500 onward is repeated.

[0049] If the determination in S600 is affirmative, in S700 the movement speed V of the circular saw 24 is set to a predetermined movement speed Vn, that is, a servo control command signal Ssv is output to the servo motor 64 so that the movement speed V becomes the predetermined movement speed Vn. In Figure 6, the transition at the variable speed end position P12 corresponds to the processing in S700.

[0050] Next, in S800, it is determined whether the circular saw 24 has moved to the cutting end position P2. This determination is made, for example, by checking whether the moved position P is greater than or equal to the cutting end position P2 (P≧P2). If the determination in S800 is negative, the determination in S800 is repeated. If the predetermined distance S is 0, the determination in S600 and the determination in S800 are the same, so the determination in S800 is immediately affirmed.

[0051] If the judgment in S800 is affirmative, in S900, a servo control command signal Ssv is output to the servo motor 64 to stop the movement of the circular saw 24, that is, to set the movement speed V to 0, and this routine is terminated. In Figure 6, the transition at the cutting end position P2 corresponds to the processing in S900.

[0052] In FB cutting, as shown in Figure 6, the travel speed V is set to a predetermined travel speed Vn when the circular saw 24 is located between the cutting start position P1 and the variable speed start position P11, and between the variable speed end position P12 and the cutting end position P2, i.e., within a predetermined distance S. In the region enclosed by the predetermined distance S (indicated as the "variable travel speed Vv setting region" in the figure), the travel speed V is set to a variable travel speed Vv. If the number of carbide tips 48 that simultaneously cut into the material to be cut 14 (hereinafter referred to as the number of teeth) is small, for example, if the number of teeth that cut simultaneously is less than 2, increasing the travel speed V may cause chipping of the carbide tips 48 (the blade portion formed on them). Preferably, a predetermined distance S is set to suppress this. By setting a predetermined distance S, for example, at a travel position P where the number of teeth that cut simultaneously is less than 2, the increase in the travel speed V due to the variable travel speed Vv is suppressed, and the travel speed V is set to the predetermined travel speed Vn. The predetermined distance S is set in advance to a suitable value based on conditions such as the shape (size) of the material to be cut 14, the shape (size) of the carbide tip 48 (and the blade formed thereon), and the number of blades cutting simultaneously. As a result, when the number of blades of the carbide tip 48 cutting into the material to be cut 14 is small, the variable movement speed Vv is set to the predetermined movement speed Vn, thereby suppressing chipping of the carbide tip 48.

[0053] In this FB cutting process, the variable travel speed Vv is set to a predetermined travel speed Vn, which is the minimum travel speed required to stably cut the material to be cut 14. The greater the cutting load FB value Efb, i.e., the smaller the load on the material to be cut 14 during cutting is compared to the maximum load state, the greater the Vv is compared to the predetermined travel speed Vn. This ensures that the material to be cut 14 is cut stably and shortens the cutting time Tc.

[0054] Furthermore, as the cutting is performed while the variable travel speed Vv is varied, the chips generated from the material 14 being cut become a mixture of large and small chips. As a result, the amount of chips that get stuck is reduced, making it less likely for the saw blade to jam, which is expected to improve the lifespan of the circular saw blade 24.

[0055] Preferably, sampling cutting SC is performed when at least one of the following occurs: the material to be cut 14 is replaced, the cutting conditions are changed, or the circular saw cutting machine 10 is started or restarted from a stopped state. This ensures that FB cutting FC is performed in appropriate response to variations in the material to be cut 14, wear of the carbide tip 48 (the blade formed thereon), changes in cutting conditions, and the starting or restarting of the circular saw cutting machine 10.

[0056] Preferably, the electronic control device 80 is equipped with a load stop function that stops the circular saw cutting machine 10 when the load power E exceeds a predetermined upper limit power Elmt, and the predetermined upper limit power Elmt is set by the sampling cutting control unit 82 based on the maximum load power Emax. As a result, the predetermined upper limit power Elmt is automatically set by the sampling cutting control unit 82 during sampling cutting SC, eliminating the need for manual setting.

[0057] Figure 7 illustrates the difference in measurement results for cutting time Tc depending on whether or not FB cutting FC is performed. Measurement numbers 1 to 11 show the measurement results for cutting time Tc based on the shape of the material to be cut 14 and combinations of cutting conditions.

[0058] In Figure 7, the material shapes are indicated by ●, which represents a round bar. For measurement number 9, ○ represents a pipe, with an outer diameter of 45 mm and an inner diameter of 35 mm. For measurement numbers 10 and 11, ■ represents a square bar, and the material diameters (50×12, 12×50) indicate the lengths of the short and long sides, respectively. The column for detected values ​​shows the values ​​actually detected during the measurement. The column for FB pause range shows the set value of the predetermined distance S, which is 7 mm in all cases in this measurement. The maximum cutting speed ratio γ shows the ratio (γ = Vvmax / Vn) of the maximum speed Vv of the variable movement speed Vv detected during the measurement to the predetermined movement speed Vn. In the column for cutting time Tc, the column for FB cutting not performed (A) shows the measurement result when the same cutting as the sampling cut SC without FB cutting is performed, and the column for FB cutting performed (B) shows the measurement result when FB cutting is performed. As shown in Figure 7, in all measurement numbers 1 to 11, measurement results showing a reduction in cutting time Tc were obtained.

[0059] Figure 8 illustrates the difference in test results regarding the lifespan of the circular saw 24 depending on whether or not FB cutting FC was performed. For the circular saw 24 with 80 teeth, the test results performed on pipe material with an outer diameter of 44 mm and an inner diameter of 29 mm under the described cutting conditions are shown in Test Numbers 1 and 2.

[0060] In the column for the number of possible cuts (lifetime), the column for "FB cut not performed (C)" shows the number of possible cuts (lifetime) when the same cuts as the sample cut SC without FB cuts are performed, while the column for "FB cut performed (D)" shows the number of possible cuts (lifetime) when FB cuts are performed. As shown in Figure 8, in both test numbers 1 and 2, test results were obtained that confirmed an improvement in the number of possible cuts (lifetime).

[0061] As described above, the circular saw cutting machine 10 of this embodiment cuts the material to be cut 14 by rotating the circular saw 24 at a predetermined rotational speed Nn and moving it in the cutting direction f at a predetermined movement speed Vn, and the sampling cutting control unit 82 performs sampling cutting SC to detect the cutting start position P1 of the circular saw 24 when the carbide tip 48 starts to cut into the material to be cut 14, the cutting end position P2 of the circular saw 24 when the state in which the carbide tip 48 cuts into the material to be cut 14 is released, and the maximum load power Emax which is the maximum value of the load power E of the circular saw rotation drive device 26 (circular saw drive motor 54), and the cutting after sampling cutting SC The system includes an FB cutting control unit 84 that performs FB cutting FC, in which the circular saw 24 is rotated at a predetermined rotational speed Nn while being moved in the cutting direction f at a predetermined movement speed Vn, and the movement speed V of the circular saw between the cutting start position P1 and the cutting end position P2 is varied from the predetermined movement speed Vn to a variable movement speed Vv corresponding to the cutting load FB value Efb calculated at predetermined cycles t, thereby cutting the material to be cut 14. The variable movement speed Vv is set with the predetermined movement speed Vn as the lower limit, and the larger the cutting load FB value Efb, the greater the movement speed Vn becomes. As a result, in FB cutting FC, the variable movement speed Vv is set with the predetermined movement speed Vn as the lower limit, and the larger the cutting load FB value Efb, i.e., the smaller the cutting load on the material to be cut 14 is compared to the maximum load state. Therefore, the material to be cut 14 is cut stably and the cutting time Tc is shortened. Furthermore, since the amount of chips generated during cutting that become jammed into the saw blade is reduced, an improvement in the lifespan of the circular saw can be expected.

[0062] Furthermore, according to the circular saw cutting machine 10 of this embodiment, the cutting load FB value Efb is calculated as the value obtained by dividing the maximum load power Emax by the load power E, and the variable travel speed Vv is the value obtained by multiplying the cutting load FB value Efb by a predetermined travel speed Vn. Thus, in FB cutting FC, the variable travel speed Vv is calculated using a simple calculation formula, with a predetermined travel speed Vn that can stably cut the material to be cut 14 as the lower limit, and is set to be greater than the predetermined travel speed Vn as the cutting load FB value Efb is larger, that is, as the load on the material to be cut 14 during cutting is smaller compared to the maximum load state.

[0063] Furthermore, according to the circular saw cutting machine 10 of this embodiment, in FB cutting FC, when the circular saw 24 is positioned between the cutting start position P1 and the variable speed start position P11, and between the variable speed end position P12 and the cutting end position P2, the movement speed V of the circular saw 24 is set to a predetermined movement speed Vn. As a result, when the number of teeth of the carbide tip 48 cutting into the material to be cut 14 is small, the variable movement speed Vv is set to the predetermined movement speed Vn, thereby suppressing chipping of the carbide tip 48.

[0064] Furthermore, according to the circular saw cutting machine 10 of this embodiment, sampling cutting SC is performed when at least one of the following conditions is met: the material to be cut 14 is replaced, the cutting conditions are changed, or the circular saw cutting machine 10 is started or restarted from a stopped state. This ensures that FB cutting FC is performed in an appropriate response to variations in the material to be cut 14, changes in cutting conditions, and the start or restart of the circular saw cutting machine 10.

[0065] Furthermore, according to the circular saw cutting machine 10 of this embodiment, the electronic control device 80 is equipped with a load stop function that stops the circular saw cutting machine 10 when the load power E exceeds a predetermined upper limit power Elmt, and the predetermined upper limit power Elmt is set by the sampling cutting control unit 82 based on the maximum load power Emax. As a result, the predetermined upper limit power Elmt is automatically set by the sampling cutting control unit 82 during sampling cutting SC, eliminating the need for manual setting.

[0066] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the present invention is not limited to this embodiment and can be implemented in other forms.

[0067] For example, in the embodiment described above, the cutting load FB value Efb was calculated as the value obtained by dividing the maximum load power Emax by the load power E. However, it is not limited to this, and for example, it may be calculated as the difference between the maximum load power Emax and the load power E. In accordance with the cutting load FB value Efb calculated as the difference, the variable travel speed Vv may be set such that, with a predetermined travel speed Vn as the lower limit, the greater the cutting load FB value Efb, the greater the Vv exceeds the predetermined travel speed Vn.

[0068] Furthermore, in the above-described embodiment, a carbide saw blade was used in which a carbide tip 48 was fixed to the outer circumference of the base metal 46 by brazing. However, the invention is not limited to this, and the saw blade may also be used in which a tip made of, for example, ceramic is fixed to the outer circumference of the base metal 46, or a cutting edge is formed integrally with the base metal 46 on the outer circumference, and the saw blade can be reused by sharpening the cutting edge each time it reaches the end of its lifespan.

[0069] Furthermore, although the circular saw cutting machine 10 in the above-described embodiment was of the swing type, it is not limited to this, and may be of the horizontal sliding type, vertical sliding type, etc.

[0070] Furthermore, although the above-described embodiment involved cutting one of the materials to be cut 14, the present invention is also applicable when, for example, multiple materials to be cut 14 are fixed in a parallel arrangement and multiple materials to be cut 14 simultaneously. In addition, the materials to be cut 14 may be made of various materials such as aluminum alloy, general steel, alloy steel, or stainless steel.

[0071] Furthermore, in the above-described embodiment, the circular saw moving device 28 was equipped with a ball screw mechanism having a ball screw shaft and a servo motor 64 that rotates it, but it is not limited to this, and may also be equipped with, for example, a rack and pinion mechanism having a rack and pinion and a servo motor 64 that drives it.

[0072] It should be noted that the above is merely one embodiment, and although other examples are not provided, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, without departing from its spirit. [Explanation of symbols]

[0073] 10: Circular saw cutting machine 14: Material to be cut 24: Circular saw 26: Circular saw rotary drive device 28: Circular saw moving device 46: Base metal 48: Carbide tip (outer edge) 54: Electric motor for driving circular saw (electric motor) 82: Sampling and Cutting Control Unit 84: FB Cutting Control Unit (Feedback Cutting Control Unit) E: Load power Efb: Cutting load FB value (cutting load feedback value) Elmt: Predetermined upper limit power Emax: Maximum load power f: Cutting direction FC:FB disconnection (feedback disconnection) Nn: predetermined rotational speed P1: Cutting start position P2: Cutting end position S: Predetermined distance SC: Sampling cutoff t: predetermined period V: Movement speed Vn: Predetermined movement speed Vv: Variable movement speed

Claims

1. A circular saw cutting machine comprising: a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal material to be cut, wherein the machine cuts the material to be cut by controlling the circular saw rotation drive device and the circular saw moving device, A sampling cutting control unit performs sampling cutting, which rotates the circular saw at a predetermined rotational speed and moves it in the cutting direction at a predetermined movement speed to cut the material to be cut, and detects the cutting start position of the circular saw where the outer blade begins to cut into the material to be cut, the cutting end position of the circular saw where the cutting state of the outer blade into the material to be cut is released, and the maximum load power which is the maximum value of the load power detected during cutting at the predetermined movement speed and predetermined rotational speed of the circular saw rotation drive device. The system includes a feedback cutting control unit that, in cutting the material to be cut after the sampling cut, rotates the circular saw at a predetermined rotational speed while moving it at a predetermined speed in the cutting direction, and changes the speed of the circular saw between the cutting start position and the cutting end position at predetermined intervals according to a cutting load feedback value calculated based on the maximum load power and the load power detected during cutting at the predetermined rotational speed, thereby performing feedback cutting to cut the material to be cut. The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut. The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. A circular saw cutting machine characterized by the following features.

2. A circular saw cutting machine comprising: a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal material to be cut, wherein the machine cuts the material to be cut by controlling the circular saw rotation drive device and the circular saw moving device, A sampling cutting control unit performs sampling cutting, which rotates the circular saw at a predetermined rotational speed and moves it in the cutting direction at a predetermined movement speed to cut the material to be cut, and detects the cutting start position of the circular saw where the outer blade begins to cut into the material to be cut, the cutting end position of the circular saw where the cutting state of the outer blade into the material to be cut is released, and the maximum load power which is the maximum value of the load power detected during cutting at the predetermined movement speed and predetermined rotational speed of the circular saw rotation drive device. The system includes a feedback cutting control unit that, in cutting the material to be cut after the sampling cut, rotates the circular saw at a predetermined rotational speed while moving it at a predetermined speed in the cutting direction, and varies the speed of the circular saw between the cutting start position and the cutting end position from the predetermined speed to a variable speed corresponding to a cutting load feedback value calculated at predetermined intervals based on the maximum load power and the load power detected during cutting at the predetermined rotational speed, thereby performing feedback cutting to cut the material to be cut. The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut. The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. The cutting load feedback value is calculated as the value obtained by dividing the maximum load power by the load power, and the variable travel speed is the value obtained by multiplying the cutting load feedback value by the predetermined travel speed. A circular saw cutting machine characterized by the following features.

3. A circular saw cutting machine comprising: a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal material to be cut, wherein the machine cuts the material to be cut by controlling the circular saw rotation drive device and the circular saw moving device, A sampling cutting control unit performs sampling cutting, which rotates the circular saw at a predetermined rotational speed and moves it in the cutting direction at a predetermined movement speed to cut the material to be cut, and detects the cutting start position of the circular saw where the outer blade begins to cut into the material to be cut, the cutting end position of the circular saw where the cutting state of the outer blade into the material to be cut is released, and the maximum load power which is the maximum value of the load power detected during cutting at the predetermined movement speed and predetermined rotational speed of the circular saw rotation drive device. The system includes a feedback cutting control unit that, in cutting the material to be cut after the sampling cut, rotates the circular saw at a predetermined rotational speed while moving it at a predetermined speed in the cutting direction, and varies the speed of the circular saw between the cutting start position and the cutting end position from the predetermined speed to a variable speed corresponding to a cutting load feedback value calculated at predetermined intervals based on the maximum load power and the load power detected during cutting at the predetermined rotational speed, thereby performing feedback cutting to cut the material to be cut. The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut. The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. In the feedback cutting described above, if the circular saw is positioned between the cutting start position and a position a predetermined distance from the cutting start position in the cutting direction, and between the cutting end position and a position a predetermined distance back in the opposite direction from the cutting end position in the cutting direction, the moving speed of the circular saw is set to the predetermined moving speed. A circular saw cutting machine characterized by the following features.

4. A circular saw cutting machine comprising: a disc-shaped circular saw having a plurality of outer blades arranged in the circumferential direction on the outer circumference of a base metal; a circular saw rotation drive device including an electric motor for rotating the circular saw; and a circular saw moving device for moving the circular saw in a cutting direction to cut into a metal material to be cut, wherein the machine cuts the material to be cut by controlling the circular saw rotation drive device and the circular saw moving device, A sampling cutting control unit performs sampling cutting, which rotates the circular saw at a predetermined rotational speed and moves it in the cutting direction at a predetermined movement speed to cut the material to be cut, and detects the cutting start position of the circular saw where the outer blade begins to cut into the material to be cut, the cutting end position of the circular saw where the cutting state of the outer blade into the material to be cut is released, and the maximum load power which is the maximum value of the load power detected during cutting at the predetermined movement speed and predetermined rotational speed of the circular saw rotation drive device. The system includes a feedback cutting control unit that, in cutting the material to be cut after the sampling cut, rotates the circular saw at a predetermined rotational speed while moving it at a predetermined speed in the cutting direction, and varies the speed of the circular saw between the cutting start position and the cutting end position from the predetermined speed to a variable speed corresponding to a cutting load feedback value calculated at predetermined intervals based on the maximum load power and the load power detected during cutting at the predetermined rotational speed, thereby performing feedback cutting to cut the material to be cut. The predetermined rotational speed and predetermined moving speed are set in advance according to the material to be cut. The variable travel speed is set to be greater than the predetermined travel speed as the cutting load feedback value increases, with the predetermined travel speed being the lower limit. The circular saw cutting machine is equipped with a load stop function that stops the circular saw cutting machine when the load power exceeds a predetermined upper limit power. The predetermined upper limit power is set by the sampling cutoff control unit based on the maximum load power. A circular saw cutting machine characterized by the following features.

5. The sampling cut is performed when at least one of the following conditions is met: the material to be cut is replaced, the cutting conditions are changed, or the circular saw cutting machine is started or restarted from a stopped state. A circular saw cutting machine according to any one of features 1 to 4.

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