Numerical control device, control method, and program

Abstract

To provide a numerical control device capable of shortening tool replacement time according to a return position, a control method, and a program.SOLUTION: After machining of a work fixed to a table 27 with a fixture, a CPU of a numerical control device moves a main shaft 20 to an R point, then moves it to a Y axis ATC original point via an ATC preparation position. In a state where the main shaft 20 is moved to the Y axis ATC original point, a tool mounted to the main shaft 20 and a tool stored in a magazine are exchanged and replaced on the basis of reciprocating movement in a Z axis direction of the main shaft 20. The CPU switches a front route of the main shaft 20 for moving from the R point to the ATC preparation position to either of a first route and a second route. The first route is a route to move the main shaft 20 from the R point to the ATC preparation position. The second is a route to move the main shaft 20 from the R point to the Y axis original point, and then moves the main shaft from the Y axis original point to the ATC preparation position.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a numerical control device, a control method, and a program.

Background Art

[0002] The machine tool described in Patent Document 1 is horizontal, and the axial direction of the main spindle is the horizontal direction. By arranging the tool changing area above the machining area, the machine size in the axial direction is suppressed. When performing tool change, after moving the main spindle from the current position to the return position so that the tool does not collide with the workpiece and the jig, it moves to the machine origin in the direction orthogonal to the axial direction and then moves to the tool change preparation position. The return position is set by the user at a position where the tool does not collide with the workpiece and the jig. The machine origin is the position where the maximum escape is made in the axial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Regardless of the return position set by the user, the main spindle once moves from the return position to the machine origin and then moves to the tool change preparation position, so there is a problem that the tool change time becomes long.

[0005] An object of the present invention is to provide a numerical control device, a control method, and a program capable of shortening the tool change time according to the return position.

Means for Solving the Problems

[0006] The numerical control device according to claim 1 includes a spindle for mounting a tool, a magazine provided in a region overlapping the machining region in the axial direction of the spindle for storing the tool, and after machining a workpiece fixed by a jig on a table, the spindle is moved to a return position where the tool mounted on the spindle does not collide with the workpiece and the jig, and then passes through a tool change preparation position that is in the same position as the tool change position in the axial direction within the region, and a forward path control unit that moves to the tool change position, and in the numerical control device including a tool change unit that exchanges the tool mounted on the spindle and the tool stored in the magazine based on the reciprocating movement of the spindle in the axial direction in a state where the forward path control unit has moved the spindle to the tool change position, the forward path control unit includes a forward path switching unit that switches the path for moving the spindle from the return position to the tool change preparation position to either a first path or a second path based on the return position, the first path is a path for directly moving the spindle from the return position to the tool change preparation position, and the second path is a path for moving the spindle from the return position to an origin position in a direction orthogonal to the axial direction and then moving from the origin position to the tool change preparation position. According to this, the numerical control device can switch the path based on the return position in the forward path for moving the spindle to the tool change position, so that it is possible to shorten the tool change time according to the return position and avoid the tool mounted on the spindle from colliding with the workpiece and the jig. Note that "directly" in the "path for directly moving the spindle from the return position to the tool change preparation position" of the first path means a path that involves movement in the axial direction and has no apex (corner) in the path.

[0007] The forward path switching unit of the numerical control device according to claim 2 may switch the path based on whether the return position is on the origin position side of the tool change preparation position in the axial direction. Since the path is switched based on whether the return position is on the origin position side with respect to the tool change preparation position in the axial direction, it is possible to shorten the tool change time according to the return position and avoid the tool mounted on the spindle from colliding with the workpiece and the jig.

[0008] The forward path switching unit of the numerical control device according to claim 3 may switch the path to the first path when the return position is on the side opposite to the origin position with respect to the tool change preparation position, and switch the path to the second path when the return position is on the origin position side with respect to the tool change preparation position. In the axial direction, when the return position is on the side opposite to the origin position with respect to the tool change preparation position as a reference, the path is switched to the first path, and when it is on the origin position side, the path is switched to the second path. Therefore, the tool change time can be shortened in the first path, and in both the first path and the second path, it is possible to avoid the tool mounted on the spindle from colliding with the workpiece and the jig.

[0009] The numerical control device according to claim 4 includes a return path control unit that moves the spindle to the command point after moving the spindle from the tool change position to the return position via the tool change preparation position. The return path control unit includes a return path switching unit that switches the path for moving the spindle from the tool change preparation position to the return position and then to the command point to either a third path or a fourth path based on the return position. The third path is a path in which the spindle directly moves from the tool change preparation position to the return position and then to the command point. The fourth path may be a path in which the spindle moves from the tool change preparation position to the return position in the axial direction, then moves to the command point in a direction orthogonal to the axial direction, and then moves to the command point. Thereby, the numerical control device can also switch the path based on the return position in the return path of moving the spindle from the tool change preparation position to the command point. Therefore, it is possible to shorten the tool change time according to the return position and avoid the tool mounted on the spindle from colliding with the workpiece and the jig. Note that the "directly" in the path of "the spindle directly moves from the tool change preparation position to the return position and then to the command point" of the third path means a path that involves movement in the axial direction and has no vertex (corner) in that path.

[0010] The return position of the numerical control device according to claim 5 may be a position offset by the tool length. Since the tip of the tool can be set as the return position, even if the tool lengths are different, it is possible to avoid the tool from colliding with the workpiece and the jig during the movement of the path.

[0011] The return position of the numerical control device according to claim 6 is a position offset by the tool length. The forward path control unit includes a first return position calculation unit that calculates the return position based on a control command of the NC program. The return path control unit may include a second return position calculation unit that recalculates the return position based on the control command of the NC program. In the return path, since it is highly likely that a tool different from the tool mounted on the spindle during the forward path is mounted on the spindle, the tool length may be different between the forward path and the return path. Since the tool length offset is applied to the return position, the position of the spindle changes if the tool lengths are different. Therefore, since the return path control unit recalculates the return position based on the control command of the NC program, it is possible to avoid the tool mounted on the spindle from contacting the workpiece and the jig at the return position.

[0012] The axial direction of the spindle of the numerical control device according to claim 7 may be the horizontal direction. It can be applied to a horizontal machine in which the axial direction of the spindle is the horizontal direction.

[0013] The control method according to claim 8, after machining a workpiece fixed by a jig on a table, moves the spindle on which the tool is mounted to a return position where the tool mounted on the spindle does not collide with the workpiece and the jig, and then passes through a tool change preparation position that is the same position as the tool change position in the axial direction of the spindle, and moves to the tool change position. In the control method of the numerical control device that exchanges the tool mounted on the spindle and the tool stored in the magazine based on the reciprocating movement in the axial direction of the spindle with the spindle moved to the tool change position, the forward path control step includes a forward path switching step of switching the path for moving the spindle from the return position to the tool change preparation position to either a first path or a second path based on the return position. The first path is a path for directly moving the spindle from the return position to the tool change preparation position, and the second path is a path for moving the spindle from the return position to an origin position in a direction orthogonal to the axial direction and then moving from the origin position to the tool change preparation position. The numerical control device can obtain the effect described in claim 1 by performing the above steps.

[0014] In the program according to claim 9, after processing the workpiece fixed by a jig on the table, the spindle to which the tool is attached is moved to a return position where the tool attached to the spindle does not collide with the workpiece and the jig, and then, via a tool change preparation position that is the same position as the tool change position in the axial direction of the spindle, it moves to the tool change position, and it includes an outward path control step of moving. In the state where the spindle is moved to the tool change position, based on the reciprocating movement of the spindle in the axial direction, in the program that causes a numerical control device to function to replace the tool attached to the spindle with the tool stored in the magazine, the computer is caused to execute an outward path switching step of switching the path for moving the spindle from the return position to the tool change preparation position to either a first path or a second path based on the return position. The first path is a path for directly moving the spindle from the return position to the tool change preparation position, and the second path is a path for moving the spindle from the return position to an origin position in a direction orthogonal to the axial direction and then moving from the origin position to the tool change preparation position. It is characterized by this. The computer of the numerical control device can obtain the effect described in claim 1 by executing the above steps.

Brief Description of the Drawings

[0015]

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Embodiments for Carrying Out the Invention

[0016] Embodiments of the present invention will be described. In this embodiment, the left and right, up and down, and front and back of the machine tool 1 will be described in the direction of the arrow shown in the figure. The machine tool 1 shown in FIG. 1 is a horizontal machine tool with the axial direction of the main shaft 20 being the horizontal direction. The left and right, up and down, and front and back of the machine tool 1 are the X-axis, Y-axis, and Z-axis.

[0017] Referring to FIGS. 1 and 2, the configuration of the machine tool 1 will be described. The machine tool 1 includes a base 2, a column 5, a saddle body 10, a spindle head 18, a spindle 20, and a tool changer (ATC device) 40.

[0018] The base 2 is provided at the lower part of the machine tool 1 and is a substantially rectangular iron base that is long in the front-rear direction in plan view. A pair of guide rails 3 are provided on the rear side of the upper surface of the base 2. The pair of guide rails 3 extend in the left-right direction and are spaced apart from each other in the front-rear direction. An X-axis motor 6 is provided between the pair of guide rails 3. A table 27 (see FIG. 3, omitted in FIGS. 1 and 2) on which a workpiece (not shown) is placed is provided on the front side of the upper surface of the base 2. A pair of left and right support members 51, 52 are fixed to the front sides of both the left and right sides of the upper surface of the base 2. A magazine 45 of the ATC device 40 described later is fixed to the upper end of each of the support members 51, 52.

[0019] Column 5 is movably mounted in the left - right direction (X - axis direction) via a sliding slider 4 on a pair of guide rails 3. Column 5 horizontally moves in the left - right direction by the drive of the X - axis motor 6. Column 5 is a substantially columnar structure formed of a casting. A large through - hole 7 is provided at the center of the front surface of Column 5. On both left and right sides of the front surface of Column 5, a pair of left - right guide rails 8 are provided. The guide rails 8 extend in the up - down direction. At the top of Column 5, a Y - axis motor 13 is provided. Inside Column 5, a feed screw 14 is provided. The feed screw 14 extends in the up - down direction, and its upper end is connected to the rotation axis (not shown) of the Y - axis motor 13.

[0020] The saddle body 10 is movably mounted in the up - down direction (Y - axis direction) via a sliding slider 9 (see Fig. 2) on a pair of left - right guide rails 8. At the lower end of the saddle body 10, a saddle base 11 is integrally provided. A large notch 12 is formed at the lower part of the saddle body 10, forming a hole between it and the saddle base 11. The rear end of the saddle base 11 extends inside the through - hole 7 of Column 5. A Z - axis motor 19 is fixed to the rear end of the saddle base 11. On the upper part of the saddle base 11, a pair of left - right guide rails 16 are provided. The pair of left - right guide rails 16 extend in the front - rear direction and are spaced apart from each other in the left - right direction. A nut 15 is fixed to the rear surface of the saddle body 10. The nut 15 is screwed onto the feed screw 14 that is rotationally driven by the Y - axis motor 13. Thereby, the saddle body 10 and the saddle base 11 move in the up - down direction together with the nut 15 in response to the rotational drive of the Y - axis motor 13.

[0021] The spindle head 18 is movably mounted in the front - rear direction via a sliding slider 17 on a pair of guide rails 16 on the upper part of the saddle base 11 and horizontally moves in the front - rear direction by the drive of the Z - axis motor 19. The spindle head 18 protrudes forward and retracts from the hole formed by the notch 12 at the lower part of the saddle body 10 and the saddle base 11. The feed screw 14 is provided at a position offset to the right from the center of the front surface. Therefore, when the saddle body 10 and the saddle base 11 rise, the spindle head 18 and the feed screw 14 do not interfere with each other. A spindle motor 21 is fixed to the rear end of the spindle head 18.

[0022] The main spindle 20 is rotatably supported by the main spindle head 18 and is rotationally driven by the main spindle motor 21. The main spindle 20 extends in the front-rear direction. The axial direction of the main spindle 20 is the Z-axis direction. A tapered hole for mounting a tool holder (not shown) is provided on the front end face of the main spindle 20. A tool is held by the tool holder. A known tool clamping device (not shown) is incorporated in the main spindle 20. The tool clamping device clamps the tool holder by clamping the pull stud of the tool holder mounted in the tapered hole.

[0023] The ATC device 40 includes a magazine 45 and ten gripping portions 50. The substantially cylindrical magazine 45 is supported in front of the upper part of the front surface of the column 5 by support members 51 and 52 in a posture with its axis oriented in the front-rear direction. The ten gripping portions 50 are radially arranged and supported along the outer periphery of the magazine 45. The gripping portion 50 includes a pot. A tool holder is detachably mounted in the pot. The magazine 45 can rotate and position the ten gripping portions 50 about the axis by a magazine motor 47 (see FIG. 5).

[0024] With reference to FIGS. 1 to 3, the machining area and the ATC area will be described. The machine origin is the position where the respective machine coordinates of the X-axis and the Y-axis are 0 and the machine coordinate of the Z-axis is at the origin dimension. The origin dimension of the Z-axis is the rear end of the machining area shown in FIG. 2 and is determined according to the structure of the machine tool 1. The machine origin of the X-axis is the X-axis origin (X = 0 mm), the machine origin of the Y-axis is the Y-axis origin (Y = 0 mm), and the machine origin of the Z-axis is the Z-axis origin (Z = origin dimension).

[0025] The machining area is provided in the space on the base 2 side (lower side) with respect to the Y-axis origin. The ATC area is provided in the space on the side opposite to the machining area (upper side) with respect to the Y-axis origin. The machining area is an area for machining the workpiece fixed to the table 27. The ATC area is an area for tool change. As shown in FIG. 3, the ATC area is provided above the machining area in the Y-axis direction and at a position overlapping the machining area in the Z-axis direction. Thereby, the machine tool 1 can make the machine size in the Z-axis direction more compact than a machine tool having the ATC area provided behind the machining area. Therefore, the machine tool 1 can reduce the installation area in a factory or the like.

[0026] Referring to FIGS. 3 and 4, the outline of the tool change operation will be described. In the machining state where the machine tool 1 machines a workpiece, the spindle 20 is located in the machining area. After the machining by the tool 23 mounted on the spindle 20 is completed, the machine tool 1 executes a tool change operation. The tool change operation includes a forward path and a return path for the path along which the spindle 20 moves. In this embodiment, "moving the spindle 20" is synonymous with "moving the spindle head 18".

[0027] The forward path is the path for moving the spindle 20 from the current position to the ATC origin (see FIG. 3), and the return path is the path for moving the spindle 20 from the ATC origin to the command point (see FIG. 4). The ATC origin is a reference point at the time of tool change provided in the ATC area and is a position where the magazine 45 can rotate. The command point is the target position for moving the spindle 20 after the tool change and can be set by G100 described later.

[0028] The forward path will be described. As shown in FIG. 3, the machine tool 1 moves the spindle 20 in the +Z-axis direction from the current position, passes through the R point described later, and moves to the ATC preparation position along the first path or the second path described later. The ATC preparation position is a position having the same coordinates as the ATC position described later in the Z-axis direction. The method for determining the first path and the second path in the forward path will be described later. Next, the machine tool 1 raises the spindle 20 from the ATC preparation position to the Y-axis ATC origin. The Y-axis ATC origin is a position having the same coordinates as the ATC origin in the Y-axis direction and corresponds to the ATC position (the "tool change position" of the present invention). At this time, the tool 23 mounted on the spindle 20 engages with the empty pot of the gripping portion 50 directly below the magazine 45 from below. Thus, the forward path is completed.

[0029] In this state, the machine tool 1 retracts the spindle 20 from the Y-axis ATC origin in the +Z-axis direction and moves it to the ATC origin. At this time, since the position of the tool 23 engaged with the pot of the gripping part 50 is fixed, the tool 23 is pulled out from the spindle 20. The machine tool 1 rotates the magazine 45 and then positions the gripping part 50 holding the next tool to be mounted directly below the magazine 45. At this time, the next tool faces the front of the spindle 20. In this state, as shown in FIG. 4, the machine tool 1 advances the spindle 20 at the ATC origin in the -Z-axis direction and moves it to the Y-axis ATC origin. Thereby, the next tool is mounted on the spindle 20. Thus, the tool change is completed.

[0030] The return path will be described. As shown in FIG. 4, when the next tool is mounted on the spindle 20, the machine tool 1 lowers the spindle 20 from the Y-axis ATC origin to the ATC preparation position. Next, after the machine tool 1 moves the spindle 20 from the ATC preparation position along the third path or the fourth path described later to the R point described later, it moves to the command point set by G100. The method for determining the third path and the fourth path in the return path will be described later. Thus, the return path is completed and a series of tool change operations are completed.

[0031] Referring to FIG. 5, the electrical configuration of the machine tool 1 will be described. The machine tool 1 includes a numerical control device 30, a spindle motor 21, an X-axis motor 6, a Y-axis motor 13, a Z-axis motor 19, a magazine motor 47, drive circuits 61 to 65, encoders 21A, 6A, 13A, 19A, 47A, an operation panel 25, etc.

[0032] The numerical control device 30 includes a CPU 31, a ROM 32, a RAM 33, a storage device 34, a communication I / F 35, an input / output interface 36, etc. The CPU 31 comprehensively controls the numerical control device 30. The ROM 32 stores various programs such as an NC control program. The NC control program executes the NC control process (see FIG. 6) described later. The RAM 33 stores various data during the execution of various processes. The storage device 34 is a non-volatile memory and stores various data in addition to the NC program for machining, for example. The communication I / F 35 can be connected to a terminal (not shown) by wire or wirelessly. The input / output interface 36 is connected to the operation panel 25 and the drive circuits 61 to 65.

[0033] The spindle motor 21 rotates the spindle 20 with a tool attached. The X-axis motor 6, the Y-axis motor 13, and the Z-axis motor 19 relatively move the workpiece and the spindle 20 in the X-axis, Y-axis, and Z-axis directions. The spindle motor 21, the X-axis motor 6, the Y-axis motor 13, the Z-axis motor 19, and the magazine motor 47 are servo motors. The drive circuit 61 controls the spindle motor 21 based on a control signal from the CPU 31. The drive circuit 62 controls the X-axis motor 6 based on a control signal from the CPU 31. The drive circuit 63 controls the Y-axis motor 13 based on a control signal from the CPU 31. The drive circuit 64 controls the Z-axis motor 19 based on a control signal from the CPU 31. The drive circuit 65 controls the magazine motor 47 based on a control signal from the CPU 31.

[0034] The encoder 21A detects the rotational position of the spindle motor 21 and transmits the detection signal to the drive circuit 61. The drive circuit 61 performs feedback control of the spindle motor 21 based on the detection signal. The encoder 6A detects the rotational position of the X-axis motor 6 and transmits the detection signal to the drive circuit 62. The drive circuit 62 performs feedback control of the X-axis motor 6 based on the detection signal. The encoder 13A detects the rotational position of the Y-axis motor 13 and transmits the detection signal to the drive circuit 63. The drive circuit 63 performs feedback control of the Y-axis motor 13 based on the detection signal. The encoder 19A detects the rotational position of the Z-axis motor 19 and transmits the detection signal to the drive circuit 64. The drive circuit 64 performs feedback control of the Z-axis motor 19 based on the detection signal. The encoder 47A detects the rotational position of the magazine motor 47 and transmits the detection signal to the drive circuit 65. The drive circuit 65 performs feedback control of the magazine motor 47 based on the detection signal. The operation panel 25 can display and input various information.

[0035] The command format for the tool change operation will be described. The tool change operation can be set by a control command in the NC program. As the command format, for example, commands such as G100 and M06 can be used. Specific examples of G100 and M06 are as follows. ·G100 T_L_X_Y_Z_R_ ·M06 T_L_X_Y_Z_R_ T, L, X, Y, Z, and R are addresses. T is the tool number, pot number, or group number. L designates the T modal value after G100. X, Y, and Z are the coordinate values of the X, Y, and Z of the command point. R is the coordinate value of the return position (R point) of the Z-axis, which is the coordinate value of a position where the tool does not contact the workpiece and the jig on the table. Regarding the positioning of the spindle 20 to the R point, the CPU 31 operates by multiplying with the tool length offset. The tool length offset is to correct the coordinate value of the Z-axis so that the tip of the tool becomes the reference point.

[0036] Referring to FIGS. 6 to 14, the NC control process will be described. The user selects an NC program on the operation panel 25. When the CPU 31 receives an operation to execute the NC program selected on the operation panel 25, it reads the NC control program from the ROM 32 and executes this process.

[0037] As shown in FIG. 6, the CPU 31 reads the selected NC program from the storage device 34 (S11). The CPU 31 interprets one block from the first line of the read NC program (S12). The CPU 31 determines whether the control command of the interpreted block is M30 (end command) (S13). If the interpreted control command is not M30 (S13: NO), the CPU 31 determines whether the interpreted control command is G100 or M06 (S14). If it is neither G100 nor M06 (S14: NO), the CPU 31 executes the interpreted control command (S15). The CPU 31 moves to the next block (S21), returns to S12, and repeats the above process. If the control command of the interpreted block is G100 or M06 (S14: YES), the CPU 31 executes the forward path determination process.

[0038] Referring to FIG. 7, the forward path determination process will be described. When the interpreted control command is G100, the CPU 31 acquires the coordinate value of the R point from the R address of G100 (S31). In order for the CPU 31 to determine the forward path from the current position to the ATC origin, in the Z-axis direction, it determines whether the R point is closer to the machine origin side than the ATC preparation position (S32). The ATC preparation position is stored in advance in the storage device 34. When the R point is located on the side opposite to the machine origin side (Z-axis - direction side) with respect to the ATC preparation position (S32: NO), the CPU 31 determines the first path (S33). When the R point is located on the machine origin side (Z-axis + direction side) with respect to the ATC preparation position (S32: YES), the CPU 31 determines the second path (S34). Specific examples of the first path and the second path will be described later. The CPU 31 stores the determined path in the RAM 33 (S35). The CPU 31 ends the forward path determination process, returns to the flow in FIG. 6, and executes the return path determination process (S17).

[0039] Referring to FIG. 8, the return path determination process will be described. The CPU 31 re-acquires the coordinate value of the R point from the R address of G100 (S41). Regarding the reason for re-acquiring the R point, in the return path, since it is highly likely that a next tool different from the tool 23 mounted on the main shaft 20 during the forward path is mounted on the main shaft 20, the tool length may be different between the forward path and the return path. As described above, since the tool length offset is applied to the R point, if the tool length is different, the position of the main shaft 20 also changes. Therefore, it is advisable for the CPU 31 to re-acquire the coordinate value of the R point based on the tool length of the next tool newly mounted on the main shaft 20 during tool change.

[0040] Here, for the tool length in the forward path, if there is a tool length correction command (G43H) before the current G100, the tool length of the tool number specified by the H address may be acquired. Note that the tool length of the tool number specified by the T address of the previous G100 may simply be acquired. On the other hand, for the tool length in the return path, if there is a tool length correction command (G43 H) at the same time as the current G100 command (i.e., when described in one block such as "G100T_X_Y_Z_R_G43H"), the tool length of the tool number specified by the H address may be acquired. Regarding this as well, the tool length of the tool number specified by the T address of the current G100 may simply be acquired.

[0041] In order for the CPU 31 to determine the return path from the ATC origin to the command point, in the Z-axis direction, it is determined whether the R point re-acquired in S41 is closer to the machine origin side than the ATC preparation position (S42). If the R point is located on the side opposite to the machine origin side with respect to the ATC preparation position (S42: NO), the CPU 31 determines the third path (S43). If the R point is located closer to the machine origin side than the ATC preparation position (S42: YES), the CPU 31 determines the fourth path (S44). Specific examples of the third path and the fourth path will be described later. The CPU 31 stores the determined path in the RAM 33 (S45). The CPU 31 ends the return path determination process and returns to the flow of FIG. 6. Subsequently, the CPU 31 executes the forward path execution process (S18).

[0042] Referring to FIG. 9, the forward path execution process will be described. The CPU 31 refers to the path stored in the RAM 53 and determines whether the forward path is the first path (S51).

[0043] The case of the first path (S51: YES) will be described. As shown in FIGS. 3 and 11, the CPU 31 moves the spindle 20 from the current position in the +Z-axis direction and retracts it to the R point (S52). The R point is a return point, and is set at a position where the tool 23 mounted on the spindle 20 does not contact the workpiece and the jig fixed on the table 27. As described above, in the Z-axis direction, the R point is located on the side opposite to the machine origin side with respect to the ATC preparation position (see FIG. 11). In this case, no matter where the spindle 20 is moved in the +Z-axis direction from the R point, the tool 23 does not contact the workpiece and the jig. Therefore, the CPU 31 moves the spindle 20 from the R point toward the ATC preparation position in all directions of the X-axis, Y-axis, and Z-axis (S53). Since the CPU 31 directly moves the spindle 20 to the ATC preparation position without passing through anywhere between the R point and the ATC preparation position, the moving time can be shortened compared with the case of passing through the machine origin side. Note that "directly move" means a path that involves movement in the Z-axis direction and has no apex (corner) in the path, and includes, for example, a path with a slightly curved movement path.

[0044] After moving the spindle 20 to the ATC preparation position, the CPU 31 moves the spindle 20 in the +Y-axis direction and raises it to the Y-axis ATC origin (S54). The Y-axis ATC origin has the same coordinate value as the ATC origin in the Y-axis direction. The Y-axis ATC origin corresponds to the pot position of the gripping portion 50 directly below the magazine 45. Therefore, when the spindle 20 rises to the Y-axis ATC origin, the tool 23 mounted on the spindle 20 is mounted from below to the empty pot. Thus, the movement of the first path is completed.

[0045] The case of the second path (S51: NO) will be described. As shown in FIGS. 3 and 12, the CPU 31 moves the spindle 20 from the current position in the +Z-axis direction and retracts it to the R point (S55). As described above, in the Z-axis direction, the R point is located closer to the machine origin side than the ATC preparation position (see FIG. 12). In this case, there is a possibility that the workpiece and the jig are located between the R point and the ATC preparation position. Therefore, if the spindle 20 is directly moved from the R point toward the ATC preparation position as in the first path, there is a possibility of contacting the workpiece and the jig. Therefore, the CPU 31 moves the spindle 20 from the R point in the +X-axis or -X-axis direction together with the +Y-axis direction and raises it to the Y-axis origin (S56). After the spindle 20 reaches the Y-axis origin and the X-axis moves to the ATC preparation position, the CPU 31 moves from the Y-axis origin in the -Z-axis direction and advances to the ATC preparation position (S57). In this way, by moving the spindle 20 from the R point via the Y-axis origin to the ATC preparation position, it is possible to prevent the tool 23 mounted on the spindle 20 from contacting the workpiece and the jig. After moving the spindle 20 to the ATC preparation position, the CPU 31 moves the spindle 20 in the +Y-axis direction and raises it to the Y-axis ATC origin (S58). The tool 23 mounted on the spindle 20 is mounted from below onto the empty pot. Thus, the movement of the second path is completed.

[0046] Returning to the flow of FIG. 6, after the CPU 31 raises the spindle 20 to the Y-axis ATC origin, it executes ATC (tool change) (S19). The CPU 31 moves the spindle 20 from the Y-axis ATC origin to the ATC origin. Thereby, the tool 23 is pulled out from the spindle 20. The machine tool 1 rotates the magazine 45 and positions the gripping portion 50 that holds the next tool to be mounted directly below the magazine 45. The CPU 31 moves the spindle 20 at the ATC origin to the Y-axis ATC origin. Thereby, the next tool is mounted on the spindle 20, and the ATC of S19 is completed. Next, the CPU 31 executes a return path execution process (S20).

[0047] Referring to FIG. 10, the return path execution process will be described. The CPU 31 refers to the path stored in the RAM 53 and determines whether the return path is the third path (S61).

[0048] The case of the third path (S61: YES) will be described. As shown in FIGS. 4 and 13, the CPU 31 moves the spindle 20 in the -Y direction from the Y-axis ATC origin and descends to the ATC preparation position (S62). In the Z-axis direction, the R point is located on the side opposite to the machine origin side with respect to the ATC preparation position (see FIG. 13). In this case, no workpiece and jig are located between the ATC preparation position and the R point. Therefore, the CPU 31 moves the spindle 20 from the ATC preparation position to the R point in all directions of the X-axis, Y-axis, and Z-axis (S63). Since the CPU 31 directly moves the spindle 20 to the R point without passing through anywhere between the ATC preparation position and the R point, the moving time can be shortened compared to the case of passing through the machine origin side. Note that "directly move" means a path that involves movement in the Z-axis direction and has no apex (corner) in the path, and includes, for example, a path with a slightly curved movement path. After the CPU 31 moves the spindle 20 to the R point, it moves to the command point set by G100 (S64). Thus, the movement of the third path is completed.

[0049] The case of the fourth path (S61: NO) will be described. As shown in FIGS. 4 and 14, the CPU 31 moves the spindle 20 in the -Y direction from the Y-axis ATC origin and descends to the ATC preparation position (S65). In the Z-axis direction, the R point is located on the machine origin side with respect to the ATC preparation position (see FIG. 14). In this case, there is a possibility that a workpiece and a jig are located between the ATC preparation position and the R point. Therefore, the CPU 31 moves the spindle 20 in the +Z direction and retreats to the Z-axis R point (S66). The Z-axis R point is a position having the same coordinates as the R point in the Z-axis direction.

[0050] Then, the CPU 31 moves the spindle 20 in the Y-axis direction and the X-axis direction from the Z-axis R point while keeping the Z-axis unchanged, so as to move to the R point (S67). That is, by moving from the ATC preparation position via the Z-axis R point to the R point, it is possible to prevent the tool 23 attached to the spindle 20 from contacting the workpiece and the jig. After the CPU 31 moves the spindle 20 to the R point, it moves to the command point set by G100 (S68). Thus, the movement of the fourth path is completed.

[0051] Returning to the flow of FIG. 6, since the CPU 31 has completed a series of tool change operations of G100, it moves to the next block (S21) and interprets the next block (S12). If the interpreted next block is M30 (S13: YES), the CPU 31 ends this process.

[0052] In the above description, the R point is an example of the "return position" of the present invention. The ATC area is an example of the "area overlapping with the machining area" of the present invention. The ATC position (Y-axis ATC origin) is an example of the "tool change position" of the present invention. The ATC preparation position is an example of the "tool change preparation position" of the present invention. The CPU 31 that executes the process of S16 in FIG. 6 is an example of the "forward path switching section" of the present invention. The CPU 31 that executes the process of S17 is an example of the "return path switching section" of the present invention. The CPU 31 that executes the process of S18 is an example of the "forward path control section" of the present invention. The CPU 31 that executes the process of S19 is an example of the "tool change section" of the present invention. The CPU 31 that executes the process of S20 is an example of the "return path control section" of the present invention. The NC control program is an example of the "program" of the present invention. The CPU 31 that executes the process of S31 in FIG. 7 is an example of the "first return position calculation section" of the present invention. The CPU 31 that executes the process of S41 in FIG. 8 is an example of the "second return position calculation section" of the present invention.

[0053] As described above, the numerical control device 30 of the present embodiment includes a spindle 20 and a magazine 45. The spindle 20 mounts a tool. The magazine 45 stores tools and is provided in an ATC area that overlaps with the machining area in the Z-axis direction, which is the axial direction of the spindle 20. After machining a workpiece fixed by a jig on the table 27, the CPU 31 of the numerical control device 30 moves the spindle 20 to the R point and then moves it to the Y-axis ATC origin via the ATC preparation position. In a state where the spindle 20 is moved to the Y-axis ATC origin, based on the reciprocating movement of the spindle 20 in the Z-axis direction, the tool mounted on the spindle 20 and the tool stored in the magazine 45 are exchanged. In the numerical control device 30 having the above configuration, the CPU 31 switches the path of the forward movement of the spindle 20 from the R point to the ATC preparation position to either the first path or the second path based on the R point. The first path is a path for moving the spindle 20 from the R point to the ATC preparation position. The second path is a path for moving the spindle 20 from the R point to the Y-axis origin and then from the Y-axis origin to the ATC preparation position. Thereby, the numerical control device 30 can avoid the tool mounted on the spindle 20 from colliding with the workpiece and the jig while shortening the tool change time according to the R point in the forward movement of the spindle 20 from the R point to the ATC preparation position.

[0054] The present invention is not limited to the above embodiment, and various modifications are possible. Although the machine tool 1 is a horizontal machine tool, it may be a vertical machine tool in which the axial direction of the spindle is the vertical direction.

[0055] The machine tool 1 moves the workpiece and the tool relatively in the X-axis, Y-axis, and Z-axis directions by moving the column 5 in the X-axis direction, the spindle 20 in the Z-axis direction, and the saddle body 10 and the saddle base 11 in the Y-axis direction. However, other structures may be used. For example, the column 5 may be moved in two axial directions, the X-axis direction and the Z-axis direction, and the spindle 20 may be moved in the Y-axis direction.

[0056] In the NC control process of FIG. 6, the forward path determination process and the return path determination process are executed in S16 and S17. Both the forward path and the return path are determined first, and then the spindle 20 is moved along the determined forward path and return path. For example, the forward path determination process may be executed before moving along the forward path, and the return path determination process may be executed before moving along the return path.

Explanation of Symbols

[0057] 20 Spindle 27 Table 30 Numerical Control Device 31 CPU 45 Magazine

Claims

1. A spindle for mounting a tool, A magazine provided in an ATC area located above the machining area and having an axial position of the spindle overlapping with the machining area for storing tools, After machining a workpiece fixed by a jig on a table, even if the spindle is moved in a direction orthogonal to the axial direction, the tool mounted on the spindle moves to a return position in the axial direction where the tool does not collide with the workpiece and the jig, and then passes through a tool change preparation position located at the boundary between the machining area and the ATC area and being at the same position as the tool change position in the ATC area in the axial direction, and a forward path control unit that moves to the tool change position, A tool change unit that exchanges the tool mounted on the spindle with the tool stored in the magazine based on the reciprocating movement of the spindle in the axial direction with the spindle moved to the tool change position by the forward path control unit, In a numerical control device comprising: The forward path control unit includes a forward path switching unit that switches a path for moving the spindle from the return position to the tool change preparation position to either a first path or a second path based on the return position, The first path is a path for directly moving the spindle from the return position to the tool change preparation position, The second path is a path for moving the spindle from the return position to an origin position that is at the same position as the return position in the axial direction and is located at the boundary between the machining area and the ATC area, and then moving from the origin position to the tool change preparation position, The forward path switching unit switches the path to the first path when the return position is on the side opposite to the machine origin from the tool change preparation position in the axial direction, and switches the path to the second path when the return position is on the machine origin side from the tool change preparation position, A numerical control device characterized by the above.

2. A return path control unit is provided for moving the spindle to a command point after moving the spindle from the tool change position through the tool change preparation position to the return position, The return path control unit includes a return path switching unit that switches a path for moving the spindle from the tool change preparation position to the return position and then to the command point to either a third path or a fourth path based on the return position, The third path is a path for directly moving the spindle from the tool change preparation position to the return position and then moving to the command point, The fourth path is a path in which the main spindle is moved from the tool change preparation position to a position where the positions in the direction orthogonal to the tool change preparation position and the axial direction are the same, and the positions in the axial direction are the same as those of the return position, and then moved to the return position, and then moved to the command point. The return path switching unit When the return position is on the side opposite to the machine origin with respect to the tool change preparation position, switches the path to the third path. When the return position is on the machine origin side with respect to the tool change preparation position, switches the path to the fourth path. The numerical control device according to claim 1, characterized in that.

3. The return position is a position offset by the tool length. The numerical control device according to claim 1 or 2, characterized in that.

4. The return position is a position offset by the tool length, and The forward path control unit includes a first return position calculation unit that calculates the return position based on a control command of the NC program. The return path control unit includes a second return position calculation unit that recalculates the return position based on the control command of the NC program. The numerical control device according to claim 2, characterized in that.

5. The axial direction of the main spindle is a horizontal direction. The numerical control device according to any one of claims 1 to 4, characterized in that.

6. It is provided in an ATC area located above the machining area and where the axial position of the main spindle on which the tool is mounted overlaps with the machining area, and includes a magazine for storing tools. In a control method of a numerical control device that, after machining a workpiece fixed by a jig on a table, moves the main spindle in a direction orthogonal to the axial direction of the main spindle, and after moving to a return position in the axial direction where the tool mounted on the main spindle does not collide with the workpiece and the jig, passes through a tool change preparation position that is located at the boundary between the machining area and the ATC area and is the same position as the tool change position in the ATC area in the axial direction, and moves to the tool change position, and in a state where the main spindle is moved to the tool change position, exchanges the tool mounted on the main spindle and the tool stored in the magazine based on the reciprocating movement of the main spindle in the axial direction. The forward path control step includes a forward path switching step of switching the path for moving the main spindle from the return position to the tool change preparation position to either the first path or the second path based on the return position. The first path is a path for directly moving the spindle from the return position to the tool change preparation position. The second path is a path for moving the spindle from the return position to an origin position that is in the same position as the return position in the axial direction and is located at the boundary between the machining area and the ATC area, and then moving from the origin position to the tool change preparation position. The forward path switching step switches the path to the first path when the return position is on the side opposite to the machine origin from the tool change preparation position in the axial direction, and switches the path to the second path when the return position is on the machine origin side from the tool change preparation position. A control method characterized by the above.

7. An ATC area is provided above the machining area and the axial position of the spindle on which the tool is mounted overlaps with the machining area, and is provided with a magazine for storing tools. After machining the workpiece fixed by the jig on the table, even if the spindle is moved in a direction orthogonal to the axial direction of the spindle, the spindle moves to the return position in the axial direction where the tool mounted on the spindle does not collide with the workpiece and the jig, and then passes through the tool change preparation position that is located at the boundary between the machining area and the ATC area and is in the same position as the tool change position in the ATC area in the axial direction, and moves to the tool change position. In a program that causes a numerical control device to function to exchange the tool mounted on the spindle and the tool stored in the magazine based on the reciprocating movement of the spindle in the axial direction in a state where the spindle is moved to the tool change position, In a computer, In the forward path control step, based on the return position, execute a forward path switching step for switching the path for moving the spindle from the return position to the tool change preparation position to either the first path or the second path. The first path is a path for directly moving the spindle from the return position to the tool change preparation position. The second path is a path for moving the spindle from the return position to an origin position that is in the same position as the return position in the axial direction and is located at the boundary between the machining area and the ATC area, and then moving from the origin position to the tool change preparation position. When the return position is on the side opposite to the machine origin from the tool change preparation position in the axial direction, the forward path switching step switches the path to the first path, and when the return position is on the machine origin side from the tool change preparation position, the forward path switching step switches the path to the second path. A program characterized by the above.

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