JP7816038B2 - Numerical control device, control method, program, and storage medium - Google Patents

Description

The present invention relates to a numerical control device, a control method, a program, and a storage medium.

The machine tool described in Patent Document 1 is horizontal, with the axial direction of the spindle being horizontal. When changing tools, the spindle moves from the start position to the return position, then to the machine origin, and then to the preparation position to prevent the tool from colliding with the workpiece or jig. The start position is the position of the spindle when workpiece machining is completed. The preparation position is the position of the spindle where the tool will not collide with the workpiece or jig. The machine origin is the position where the machine coordinate of the spindle in the axial direction is the origin dimension, and the machine coordinate of the spindle in the direction perpendicular to the axial direction is 0. The position of the origin dimension in the axial direction is the position where the spindle has made the greatest axial escape, and is determined depending on the structure of the machine tool. The preparation position is the position where the spindle is positioned in preparation for gripping the tool holder holding the tool in the magazine grip arm.

Patent No. 3044782

The spindle would first move from the return position to the machine origin and then to the preparation position, which created the problem of long tool change times.

The object of the present invention is to provide a numerical control device, control method, program, and storage medium that can shorten tool change time.

According to a first aspect of the present invention, a numerical control device for controlling a machine tool having a spindle on which tools are mounted, a magazine having multiple storage compartments for storing tools, and a table on which a workpiece is fixed is provided with a storage control unit that moves the spindle from an end position, which is the position of the spindle when machining of the workpiece is completed, to a first return position that is a position away from the end position in the axial direction of the spindle from the end position and where the attached tool attached to the spindle does not collide with the workpiece, a storage position where the attached tool is stored in the storage compartment of the magazine, and a preparation position that is between the first return position and the storage position and away from the storage position in a first orthogonal direction perpendicular to the axial direction, in the order of the first return position, the preparation position, and the storage position, and then to an extraction position that is positioned in a direction away from the magazine along the axial direction relative to the storage position and where the attached tool remains in the storage compartment and is extracted from the spindle. The machine tool is provided with at least a storage control unit that moves the spindle through the first return position, the preparation position, and the storage position in this order. a position detection unit that detects the position of the spindle in a direction perpendicular to the axial direction and a second orthogonal direction perpendicular to the first orthogonal direction, the storage control unit comprising a first instruction unit that instructs the spindle to move from the first return position to the standby position in the axial direction, a second instruction unit that instructs the spindle to move from the first return position to the standby position in the first orthogonal direction and the second orthogonal direction, a third instruction unit that instructs the spindle to move from the standby position to the storage position in the first orthogonal direction, and a first determination unit that determines whether the spindle has reached the standby position in the second orthogonal direction based on the detection result of the position detection unit, and the third instruction unit begins to output instructions as soon as the second instruction unit has completed outputting instructions and the first determination unit determines that the spindle has reached the standby position in the second orthogonal direction.

When the second indicator outputs an instruction for the spindle's movement in the first orthogonal direction and the second orthogonal direction, the spindle begins to accelerate its movement speed from 0 toward the standby position from the first return position. Once the instruction output is complete, the spindle typically begins to decelerate its movement speed so as to stop moving at the standby position. In contrast, in the present invention, the third indicator outputs an instruction immediately if the spindle has reached the standby position in the second orthogonal direction when the second indicator completes its output. That is, the second indicator and the third indicator are output consecutively as long as the spindle has reached the standby position in the second orthogonal direction. Therefore, the spindle does not decelerate its movement speed toward the standby position and continues moving toward the next storage position. For example, the spindle can move from the first return position to the storage position more quickly in the first orthogonal direction and the second orthogonal direction compared to when the third indicator outputs an instruction after the second indicator completes its output and an in-position check confirms that the spindle has reached the standby position. Therefore, numerical control devices can reduce tool change time.

The storage control unit of the first aspect includes a fourth instruction unit that instructs the spindle to move from the end position in the axial direction to the first return position, and a second determination unit that determines whether the spindle has reached the first return position in the axial direction based on the detection result of the position detection unit. The first instruction unit may start outputting instructions as soon as the fourth instruction unit completes outputting instructions, and the second instruction unit may start outputting instructions when the second determination unit determines that the spindle has reached the first return position in the axial direction.

When the fourth indicator outputs a command during axial movement of the spindle, the spindle begins accelerating its movement speed from 0 as it moves from the end position to the first return position. Once the command output is complete, the spindle typically begins decelerating its movement speed so as to stop moving at the first return position. In contrast, in the present invention, the first indicator outputs a command immediately after the fourth indicator completes output. That is, the fourth indicator and the first indicator are output consecutively. Therefore, the spindle does not decelerate its movement speed as it moves toward the first return position, but continues moving toward the next preparation position. For example, compared to when the fourth indicator completes output of a command and an in-position check confirms that the spindle has reached the first return position before outputting a command from the first indicator, the spindle can move axially from the end position to the preparation position more quickly. Therefore, the numerical control device can shorten tool change time.

The storage control unit of the first aspect may include a third determination unit that determines whether the spindle has reached the ready position in the axial direction based on the detection result of the position detection unit, and may start outputting instructions from the third indication unit as soon as the second indication unit has completed outputting instructions and the first determination unit determines that the spindle has reached the ready position in the second orthogonal direction, and the third determination unit further determines that the spindle has reached the ready position in the axial direction.

When the spindle moves in the first orthogonal direction and the second orthogonal direction, even if the second indicator has completed outputting an instruction, the third indicator will not output an instruction until the spindle has reached the preparation position in the axial direction. This ensures that the spindle can be reliably moved to the storage position.

In a first aspect, the machine tool further includes a mounting control unit that, when one of the storage units in the magazine that stores an unattached tool to be used in the next machining operation is located at a position corresponding to the storage position, moves the spindle from the extraction position, through the storage position, and then the preparation position, in that order, to a second return position that is axially spaced from a start position, which is the position of the spindle when machining of the workpiece begins with the unattached tool, and where the unattached tool will not collide with the workpiece, and then moves the spindle to the start position; the position detection unit of the machine tool further detects the position of the spindle in the first orthogonal direction, and the mounting control unit detects the storage position of the spindle in the first orthogonal direction. a fifth instruction unit that instructs the spindle to move from the ready position to the second return position in the first orthogonal direction; a sixth instruction unit that instructs the spindle to move from the ready position to the second return position in the first orthogonal direction; a seventh instruction unit that instructs the spindle to move from the ready position to the second return position in the axial direction and the second orthogonal direction; and a fourth determination unit that determines whether the spindle has reached the ready position in the first orthogonal direction based on the detection result of the position detection unit, and the sixth instruction unit may start outputting instructions as soon as output of instructions by the fifth instruction unit is completed, and the seventh instruction unit may start outputting instructions as soon as the fourth determination unit determines that the spindle has reached the ready position in the first orthogonal direction.

When the fifth indicator outputs an instruction for the spindle's movement in the first orthogonal direction, the spindle begins to accelerate its movement speed from 0 as it moves from the storage position toward the ready position. Once the instruction output is complete, the spindle typically begins to decelerate its movement speed so as to stop moving at the ready position. In contrast, in the present invention, the sixth indicator outputs an instruction immediately after the fifth indicator completes output. That is, the fifth indicator and the sixth indicator are output consecutively. Therefore, the spindle does not decelerate its movement speed toward the ready position, but continues moving toward the next, second return position. For example, compared to when the sixth indicator outputs an instruction after the fifth indicator completes output and an in-position check confirms that the spindle has reached the ready position, the spindle can move from the storage position to the second return position more quickly in the first orthogonal direction. Therefore, the numerical control device can shorten tool change time.

The mounting control unit of the first aspect may further include an eighth instruction unit that instructs the spindle to move from the second return position to the start position in the axial direction, and a fifth determination unit that determines whether the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction based on the detection results of the position detection unit. The eighth instruction unit may start outputting instructions as soon as the seventh instruction unit completes outputting instructions and the fifth determination unit determines that the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction.

When the seventh indicator outputs a command during the movement of the spindle in the second orthogonal direction, the spindle begins accelerating its movement speed from 0 from the preparation position toward the second return position. Once the command output is complete, the spindle typically begins decelerating its movement speed so as to stop movement at the second return position. In contrast, in the present invention, the eighth indicator outputs a command immediately if the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction upon completion of the command output by the seventh indicator. In other words, the seventh indicator and the eighth indicator are output consecutively as long as the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction. Therefore, the spindle continues moving toward the next start position without decelerating its movement speed toward the second return position. For example, compared to when the seventh instruction unit completes output of an instruction and an in-position check confirms that the spindle has reached the second return position before outputting an instruction from the eighth instruction unit, the spindle can move more quickly in the axial direction from the preparation position to the start position. This allows the numerical control device to shorten the tool change time.

In a first aspect, the machine tool includes a cover that covers the periphery of the magazine, an opening formed in the cover and located between the storage position located inside the cover and the preparation position located outside the cover, through which the spindle can pass, a shutter that opens and closes the opening, an opening/closing drive unit that opens and closes the shutter, and an opening/closing detection unit that detects the opening/closing state of the shutter. The storage control unit includes a ninth instruction unit that instructs the opening/closing drive unit to open the shutter, and a sixth determination unit that determines whether the shutter is in the open state based on the detection result of the opening/closing detection unit. The storage control unit may instruct the ninth instruction unit to open the shutter when output of an instruction by any of the first instruction unit, the second instruction unit, or the fourth instruction unit begins, and may further begin output of an instruction by the third instruction unit as soon as the sixth determination unit determines that the shutter is in the open state. The numerical control device can confirm that the cover shutter is in the open state before outputting an instruction by the third instruction unit. Therefore, the spindle can reliably move to the storage position without colliding with the shutter.

In a first aspect, the machine tool includes a rotation detection unit that detects the rotational position of the spindle, and the storage control unit includes a tenth instruction unit that instructs the rotation of the spindle toward an orienting position, which is a rotational position of the spindle at which the attached tool can be stored in the storage unit, and a seventh determination unit that determines whether the rotational position of the spindle is at the orienting position based on the detection result of the rotation detection unit. When output of an instruction by any of the first instruction unit, the second instruction unit, or the fourth instruction unit begins, the tenth instruction unit instructs the rotation of the spindle toward the orienting position, and further, as soon as the seventh determination unit determines that the rotational position of the spindle is at the orienting position, the third instruction unit may begin outputting an instruction. The numerical control device can confirm that the rotational position of the spindle is at the orienting position before outputting an instruction by the third instruction unit. Therefore, the spindle moves to the storage position, allowing the attached tool to be securely gripped by the gripping arm.

According to a second aspect of the present invention, in order to control a machine tool having a spindle to which a tool is attached, a magazine having a plurality of storage compartments for storing tools, and a table for fixing a workpiece, a control method for a numerical control device includes a storage control step of moving the spindle from an end position, which is the position of the spindle when machining of the workpiece is completed, through a first return position that is a position away from the end position in the axial direction of the spindle from the end position and where the attached tool attached to the spindle does not collide with the workpiece, a storage position where the attached tool is stored in the storage compartment of the magazine, and a preparation position that is between the first return position and the storage position and is away from the storage position in a first orthogonal direction perpendicular to the axial direction, in the order of the first return position, the preparation position, and the storage position, and then to an extraction position that is located in a direction away from the magazine along the axial direction relative to the storage position and where the attached tool remains in the storage compartment and is extracted from the spindle, the storage control step A control method is provided for a machine, the control method comprising at least a first determination step of determining whether the spindle has reached the ready position in the second orthogonal direction based on detection results from a position detection unit that detects the position of the spindle in the axial direction and the position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and also orthogonal to the first orthogonal direction; a first instruction step of instructing the spindle to move from the first return position to the ready position in the axial direction; a second instruction step of instructing the spindle to move from the first return position to the ready position in the first orthogonal direction and the second orthogonal direction; and a third instruction step of instructing the spindle to move from the ready position to the retracted position in the first orthogonal direction, wherein output of the instruction in the third instruction step is initiated as soon as output of the instruction in the second instruction step is completed and the first determination step determines that the spindle has reached the ready position in the second orthogonal direction. Therefore, the second aspect achieves the same effects as the first aspect.

According to a third aspect of the present invention, in order to control a machine tool having a spindle to which a tool is attached, a magazine having multiple storage compartments for storing tools, and a table to fix a workpiece, a program for causing a numerical control device to function includes a storage control step for moving the spindle from an end position, which is the position of the spindle when machining of the workpiece is completed, to a first return position that is a position away from the end position in the axial direction of the spindle from the end position and where the attached tool attached to the spindle will not collide with the workpiece, a storage position where the attached tool is stored in the storage compartment of the magazine, and a preparation position that is between the first return position and the storage position and away from the storage position in a first orthogonal direction perpendicular to the axial direction, in the order of the first return position, the preparation position, and the storage position, and then to an extraction position that is located in a direction away from the magazine along the axial direction relative to the storage position and where the attached tool remains in the storage compartment and is extracted from the spindle. and a program for executing the following steps: a first determination step for determining whether the spindle has reached the ready position in the second orthogonal direction based on detection results from a position detection unit that detects the position of the spindle in the axial direction and the position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and also orthogonal to the first orthogonal direction; a first instruction step for instructing the spindle to move from the first return position to the ready position in the axial direction; a second instruction step for instructing the spindle to move from the first return position to the ready position in the first orthogonal direction and the second orthogonal direction; and a third instruction step for instructing the spindle to move from the ready position to the retracted position in the first orthogonal direction; and the program for starting output of instructions in the third instruction step as soon as output of instructions in the second instruction step is completed and the first determination step determines that the spindle has reached the ready position in the second orthogonal direction. Therefore, the third aspect achieves the same effects as the first aspect.

According to a fourth aspect of the present invention, there is provided a program for controlling a numerical control device that causes a computer to execute a storage control step of moving the spindle from an end position, which is the position of the spindle when machining of the workpiece is completed, to a first return position that is a position away from the end position in the axial direction of the spindle from the end position and where the attached tool attached to the spindle will not collide with the workpiece, a storage position where the attached tool is stored in the storage section of the magazine, and a preparation position that is between the first return position and the storage position and is away from the storage position in a first orthogonal direction perpendicular to the axial direction, and then to an extraction position that is located in a direction away from the magazine along the axial direction relative to the storage position and where the attached tool remains in the storage section and is extracted from the spindle, the program causing the computer to execute a storage control step of moving the spindle from the end position, which is the position of the spindle when machining of the workpiece is completed, to a first return position that is a position away from the end position in the axial direction of the spindle from the end position and where the attached tool attached to the spindle will not collide with the workpiece, a storage position where the attached tool is stored in the storage section of the magazine, and a preparation position that is a position between the first return position and the storage position and is away from the storage position in a first orthogonal direction perpendicular to the axial direction, and then to an extraction position that is located in a direction away from the magazine along the axial direction relative to the storage position and where the attached tool remains in the storage section and is extracted from the spindle, the program causing the computer to execute a storage control step of moving the spindle from the end position, which is and a storage medium storing a program for executing the following operations: a first determination step for determining whether the spindle has reached the ready position in the second orthogonal direction based on detection results from a position detection unit that detects the position of the spindle in the axial direction and the position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and orthogonal to the first orthogonal direction; a first instruction step for instructing the spindle to move from the first return position to the ready position in the axial direction; a second instruction step for instructing the spindle to move from the first return position to the ready position in the first orthogonal direction and the second orthogonal direction; and a third instruction step for instructing the spindle to move from the ready position to the retracted position in the first orthogonal direction; and the program for starting output of an instruction in the third instruction step upon completion of output of an instruction in the second instruction step and determination in the first determination step that the spindle has reached the ready position in the second orthogonal direction. Therefore, the fourth aspect achieves the same effects as the first aspect.

FIG. 2 is a perspective view of the machine tool 1 as seen from the front upper right. FIG. 2 is a perspective view of the machine tool 1 as seen from the lower front right. FIG. 2 is a perspective view of the machine tool 1 (magazine cover omitted) as seen from the upper right rear. FIG. 2 is a right side view of the machine tool 1 (magazine cover omitted). FIG. FIG. 10 is a diagram showing the return route of ATC operation. FIG. 2 is a block diagram showing the electrical configuration of the machine tool 1. 10 is a flowchart of an NC control process. 10 is a flowchart of a forward path execution process. 10 is a continuation of the flowchart of the forward path execution process. 10 is a flowchart of a return path execution process. 10 is a continuation of the flowchart of the return path execution process.

One embodiment of the present invention will be described. In the following description, the left-right, front-back, and up-down directions indicated by arrows in the figures will be used. The left-right, up-down, and front-back directions of the machine tool 1 correspond to the X-axis, Y-axis, and Z-axis directions of the machine tool 1, respectively. The machine tool 1 shown in Figure 1 is a horizontal type in which the main spindle 7 extends in the front-back direction (Z-axis direction), and is a column traverse type machine tool in which the column 5 moves in the X-axis and Z-axis directions.

The structure of the machine tool 1 will be explained with reference to Figures 1 to 4. The machine tool 1 includes a base 2, a column 5, an X-axis movement mechanism 11, a Z-axis movement mechanism 12, a Y-axis movement mechanism 13, a spindle head 6, a spindle 7 (see Figure 2), a control box 8, a rotary table 9, an ATC device 30 (see Figure 3), a magazine cover 10, etc.

The base 2 is a roughly rectangular parallelepiped iron base that is long in the Z-axis direction. The X-axis movement mechanism 11 is provided at the rear of the top surface of the base 2, and supports the moving body 15 so that it can move in the X-axis direction. The Z-axis movement mechanism 12 is provided on the top surface of the moving body 15. The Z-axis movement mechanism 12 supports the column 5 so that it can move in the Z-axis direction. The column 5 is an upright pillar that extends in the vertical direction. The column 5 has a vertically elongated rectangular through-hole 5A (see Figure 3) on its front surface. The through-hole 5A passes through the column 5 in the front-to-rear direction. The frame cover 20 is attached to the front of the column 5. The frame cover 20 is a vertically elongated rectangular frame body when viewed from the front, and covers the space between the column 5 and the spindle head 6. The Y-axis movement mechanism 13 is provided on the front surface of the column 5, and supports the spindle head 6 so that it can move in the Y-axis direction. The X-axis movement mechanism 11, Z-axis movement mechanism 12, and Y-axis movement mechanism 13 are equipped with, for example, guides, ball screws, and motors (X-axis motor 11A, Z-axis motor 12A, Y-axis motor 13A), and the power of these motors is used to move the moving body 15, column 5, and spindle head 6, respectively, along the guides.

The spindle head 6 extends in the Z-axis direction and is movable in the Y-axis direction along the front surface of the column 5 by the Y-axis movement mechanism 13. The spindle head 6 is movable in the Y-axis direction between the machining area and the ATC area (see Figures 4 and 5). The machining area is located in the space on the base 2 side (below) of the Y-axis origin. The Y-axis origin is the position where the Y-axis machine coordinate is 0. The ATC area is located in the space on the opposite side (above) of the Y-axis origin from the machining area. The machining area is an area where machining of a workpiece W (see Figure 5) fixed to the rotary table 9 is performed. The ATC area is an area where tool changes are performed by the ATC device 30. The ATC area is located above the machining area in the Y-axis direction and overlaps with the machining area in the Z-axis direction.

The spindle head 6 is equipped with an upper cover 28 and an armor cover 85. The upper cover 28 is fixed to the rear end of the upper surface of the spindle head 6. The upper cover 28 is a metal plate that is roughly rectangular in front view and extends upward from the rear end of the upper surface of the spindle head 6. The armor cover 85 is fixed in a suspended state to the rear end of the lower surface of the spindle head 6. The armor cover 85 comprises multiple metal plates arranged in the vertical direction and telescopically expands and contracts in the vertical direction. The upper cover 28 moves up and down together with the spindle head 6, thereby always covering the area above the spindle head 6 on the front surface of the column 5. The armor cover 85 expands and contracts in the vertical direction in response to the up and down movement of the spindle head 6, always covering the area below the spindle head 6 on the front surface of the column 5.

The spindle 7 is mounted coaxially within the spindle head 6. The spindle head 6 rotatably supports the spindle 7. A motor holder box 27 (see Figure 3) is fixed to the rear of the spindle head 6. The motor holder box 27 extends rearward from the rear of the spindle head 6 and holds the spindle motor 26 inside. The motor holder box 27 protrudes rearward from the through-hole 5A of the column 5. The output shaft of the spindle motor 26 (see Figure 7) extends forward and is coaxially connected to the rear end of the spindle 7.

The spindle 7 has a tool mounting hole 40 and a holder retaining member 19 (see Figure 5). The tool mounting hole 40 is located at the tip (front end) of the spindle 7. The tool mounting hole 40 is a generally conical tool mounting hole 40 that widens toward the tip of the spindle 7. The holder retaining member 19 is located at the back of the tool mounting hole 40. A tool holder 90 (see Figure 5) is detachably attached to the tool mounting hole 40. The tool holder 90 holds a tool 91 at one end and has a tapered portion and a pull stud 93 (see Figure 5) at the other end. The tapered portion is generally conical and fits tightly into the tool mounting hole 40 of the spindle 7. The pull stud 93 protrudes axially from the top of the tapered portion. When the tapered portion is attached to the tool mounting hole 40, the holder retaining member 19 holds the pull stud 93, securing the tool holder 90 to the spindle 7.

A pair of support members 17, 18 are provided at the rear of the base 2. The support members 17, 18 are spaced apart from each other in the left-right direction and extend upward, supporting the control box 8 from below. The control box 8 houses a control panel (not shown) inside. The control panel controls the operation of the machine tool 1. A fixed base 16 is provided on the front top surface of the base 2. The rotary table 9 is fixed to the fixed base 16. The rotary table 9 is located in front of the spindle head 6. The workpiece W (see Figure 5) is fixed to the upper surface of the rotary table 9 with a jig (not shown), and the table can rotate 360° around a rotation axis parallel to the Y-axis direction.

A pair of support columns 21, 22 are provided on the front and left and right sides of the upper surface of the base 2. As shown in Figure 3, a connecting plate 23 is fixed between the upper parts of the opposing support columns 21, 22. The ATC unit 30 is fixed to the front of the connecting plate 23. Therefore, the ATC unit 30 is located between the column 5 and the rotary table 9 and above the spindle head 6 by the support columns 21, 22. The ATC unit 30 includes a tool magazine 31, a reducer 32, a magazine motor 33, etc. The tool magazine 31 includes a magazine base 37 and multiple grip arms 35. The magazine base 37 is approximately disk-shaped and is supported on the front of the connecting plate 23 so that it can rotate around an axis parallel to the Z-axis direction. The reducer 32 and magazine motor 33 are attached to the tool magazine 31. The output shaft (not shown) of the magazine motor 33 is connected to the rotation shaft (not shown) of the magazine base 37 via the reducer 32. The power of the magazine motor 33 is transmitted to the rotation axis of the magazine base 37 via the reducer 32. Multiple grip arms 35 are arranged in a row along the outer periphery of the magazine base 37 and extend radially outward. The tips of the grip arms 35 grip the tool holder 90 in the Y-axis direction perpendicular to the tool holder 90 when the tool holder 90 is laid horizontally. The shape of the grip arms 35 is not particularly limited, and they may be configured to grip the tool holder 90. The grip arms 35, which exchange tools with the spindle 7, move to ATC position C (see Figure 5) of the tool magazine 31. ATC position C is the lowest position of the tool magazine 31.

As shown in Figures 1 and 2, a magazine cover 10 is fixed to the front of the upper part of each of the support columns 21, 22. The magazine cover 10 is box-shaped and covers the periphery of the tool magazine 31. The magazine cover 10 prevents chips and cutting fluid splashes from adhering to the tool magazine 31. An opening 102 is provided in the bottom wall 101 of the magazine cover 10. The opening 102 is rectangular when viewed from the bottom, and is located directly below ATC position C, which is the lowest part of the tool magazine 31. A shutter 103 is provided in the opening 102. The shutter 103 opens and closes the opening 102 under the control of a control panel. When the shutter 103 is open, the spindle 7 passes through the opening 102 and can move to ATC position C.

An overview of the tool changing operation will be explained with reference to Figures 5 and 6. When the machine tool 1 is in a machining state cutting the workpiece W, the spindle 7 is located in the machining area. After machining using the tool 91 attached to the spindle 7 is completed, the machine tool 1 executes a tool changing operation. The tool changing operation includes a tool storing operation in which the used tool 91 is stored in the tool magazine 31, and a tool loading operation in which the next tool 92 to be used is loaded onto the spindle 7 and moved to a position where machining will begin. The path traveled by the spindle 7 when storing the tool is referred to as the outbound path, and the path traveled when loading the tool is referred to as the return path. Note that in this embodiment, "moving the spindle 7" is synonymous with "moving the spindle head 6."

The outbound path is the path along which the spindle 7 moves from the machining end position Q1 to the ATC origin position D (see Figure 5). The return path is the path along which the spindle 7 moves from the ATC origin position D to the machining start position Q2 (see Figure 6). The machining end position Q1 is the position of the spindle 7 when machining of the workpiece W is completed according to the NC program. The ATC origin position D is a reference point set in the ATC area for tool changes, and is a position to which the tool magazine 31 can rotate. The machining start position Q2 is the position of the spindle 7 when machining of the workpiece W begins according to the NC program, and is the target position to which the spindle 7 is moved after the tool change.

The forward path will now be explained. As shown in Figure 5, the machine tool 1 moves the spindle 7 from the machining end position Q1 in the +Z direction, passes through the first return position A1, and moves to the ATC preparation position B. The first return position A1 is set in the +Z direction away from the machining end position Q1, at a position where the tool 91 attached to the spindle 7 does not come into contact with the workpiece W or jig fixed on the rotary table 9. The first return position A1 is at the same coordinate as the machining end position Q1 in the X and Y directions. The ATC preparation position B is at the same coordinate as the ATC position C in the X and Z directions. The ATC position C is the position where the grip arm 35 of the tool magazine 31 grips the tool holder 90 holding the tool 91. The ATC preparation position B is at the -Y direction away from the ATC position C, at which the spindle 7 is positioned so that the grip arm 35 can grip and release the tool holder 90 in the Y direction.

Next, the machine tool 1 raises the spindle 7 from the ATC preparation position B to the ATC position C. At this time, the tool holder 90 attached to the spindle 7 engages from below with the empty grip arm 35 located directly below the tool magazine 31. In this state, the machine tool 1 moves the spindle 7 backward in the +Z direction from the ATC position C to the ATC origin position D. At this time, the tool holder 90 is withdrawn from the spindle 7. This completes the forward movement of the spindle 7 when storing tools.

The return path will now be explained. The machine tool 1 rotates the tool magazine 31 and positions the grip arm 35, which holds the next tool 92 to be loaded, directly below the tool magazine 31. At this time, the next tool 92 is positioned in front of the spindle 7. In this state, as shown in Figure 6, the machine tool 1 moves the spindle 7, which is at ATC origin position D, forward in the negative direction of the Z axis to ATC position C. This loads the next tool 92 onto the spindle 7.

Once the next tool 92 is attached to the spindle 7, the machine tool 1 lowers the spindle 7 from the ATC position C to the ATC preparation position B. Next, the machine tool 1 moves the spindle 7 from the ATC preparation position B to the second return position A2, and then moves it to the machining start position Q2. The second return position A2 is set in the positive Z-axis direction away from the machining start position Q2, so that the tool 91 attached to the spindle 7 does not come into contact with the workpiece W or jig fixed on the rotary table 9. The second return position A2 is at the same coordinate in the X-axis and Y-axis directions as the machining start position Q2. This completes the return movement of the spindle 7 when attaching the tool, and completes the tool change operation sequence.

The electrical configuration of the machine tool 1 will be described with reference to Figure 7. The machine tool 1 includes a numerical control device 50, a spindle motor 26, an X-axis motor 11A, a Y-axis motor 13A, a Z-axis motor 12A, a magazine motor 33, a shutter motor 34, drive circuits 61-66, encoders 26A, 11B, 12B, 13B, 33A, and 34A, an operation panel 25, and the like.

The numerical control device 50 comprises a CPU 51, ROM 52, RAM 53, storage device 54, communication I/F 55, input/output interface 56, etc. The CPU 51 provides overall control of the numerical control device 50. The ROM 52 stores various programs, such as an NC control program. The NC control program executes the NC control process (see Figure 8), which will be described later. The RAM 53 stores various data during the execution of various processes. The storage device 54 is non-volatile memory, and stores, for example, NC programs for machining as well as various data. The communication I/F 55 can be connected to a terminal (not shown) via wired or wireless connection. The input/output interface 56 connects the operation panel 25 to the drive circuits 61-66.

The spindle motor 26 rotates the spindle 7 to which a tool is attached. The X-axis motor 11A, Z-axis motor 12A, and Y-axis motor 13A move the workpiece W and spindle 7 relatively in the X-axis, Z-axis, and Y-axis directions. The magazine motor 33 rotates the tool magazine 31. The shutter motor 34 opens and closes the shutter 103. The spindle motor 26, X-axis motor 11A, Z-axis motor 12A, Y-axis motor 13A, magazine motor 33, and shutter motor 34 are servo motors. The drive circuit 61 controls the spindle motor 26 based on a control signal from the CPU 51. The drive circuit 62 controls the X-axis motor 11A based on a control signal from the CPU 51. The drive circuit 63 controls the Z-axis motor 12A based on a control signal from the CPU 51. The drive circuit 64 controls the Y-axis motor 13A based on a control signal from the CPU 51. The drive circuit 65 controls the magazine motor 33 based on a control signal from the CPU 51. The drive circuit 66 controls the shutter motor 34 based on a control signal from the CPU 51.

Encoder 26A detects the rotational position of the spindle motor 26 and sends the detection signal to the drive circuit 61. The drive circuit 61 performs feedback control of the spindle motor 26 based on the detection signal and outputs the rotation angle of the spindle 7 corresponding to the rotational position to the CPU 51. Encoder 11B detects the rotational position of the X-axis motor 11A and sends the detection signal to the drive circuit 62. The drive circuit 62 performs feedback control of the X-axis motor 11A based on the detection signal and outputs the position of the spindle 7 in the X-axis direction corresponding to the rotational position to the CPU 51. Encoder 12B detects the rotational position of the Z-axis motor 12A and sends the detection signal to the drive circuit 63. The drive circuit 63 performs feedback control of the Z-axis motor 12A based on the detection signal and outputs the position of the spindle 7 in the Z-axis direction corresponding to the rotational position to the CPU 51. Encoder 13B detects the rotational position of the Y-axis motor 13A and sends the detection signal to the drive circuit 64. The drive circuit 64 performs feedback control of the Y-axis motor 13A based on the detection signal. Encoder 33A detects the rotational position of magazine motor 33 and sends this detection signal to drive circuit 65. Drive circuit 65 performs feedback control of magazine motor 33 based on the detection signal and outputs the position of main shaft 7 in the Y-axis direction corresponding to the rotational position to CPU 51. Encoder 34A detects the rotational position of shutter motor 34 and sends this detection signal to drive circuit 66. Drive circuit 66 performs feedback control of shutter motor 34 based on the detection signal and outputs the open/closed state of shutter 103 corresponding to the rotational position to CPU 51. Operation panel 25 is capable of displaying and inputting various information.

The command format for tool change operations will be explained below. Tool change operations can be set using control commands in the NC program. For example, commands such as G100 and M06 can be used as the command format. The coordinate value of the machining start position Q2 and the Z-axis coordinate values of the first return position A1 and second return position A2 are specified and included in the tool change command. Specific examples of G100 and M06 are as follows:
・G100T_L_X_Y_Z_R_
・M06T_L_X_Y_Z_R_
T, L, X, Y, Z, and R are addresses. T is a tool number, pot number, or group number. L specifies the T modal value after G100. The T modal value indicates the tool number or pot number to be replaced in subsequent tool change commands. X, Y, and Z are the X, Y, and Z coordinate values of the machining start position Q2. R is the Z-axis coordinate value of the first return position A1 and the second return position A2, which is the coordinate value of the position where the tool does not contact the workpiece or jig on the table. Furthermore, when positioning the spindle 7 to the first return position A1 and the second return position A2, the CPU 51 applies a tool length offset. The tool length offset is a correction of the Z-axis coordinate value so that the tip of the tool becomes the reference point. The tool length offset value is, for example, a value obtained by measuring in advance the length in the Z-axis direction between the tip of the tool and the machine coordinate position of the spindle 7 when the tool is held in the tool holder 90 and the tool holder 90 is attached to the spindle 7. The tool offset value may be specified as being included in the tool change command as described above, or may be set in advance by the user as a parameter and stored in the storage device 54 in association with the tool number.

The NC control process will be explained with reference to Figures 8 to 12. The user selects an NC program on the operation panel 25. When the CPU 51 receives an instruction to execute the NC program selected on the operation panel 25, it reads the NC control program from the ROM 52 and executes this process.

As shown in FIG. 8, the CPU 51 reads the selected NC program from the storage device 54 (S11). The CPU 51 interprets one block from the first line of the read NC program (S12). The CPU 51 determines whether the control command in the interpreted block is M30 (end command) (S13). If the interpreted control command is not M30 (S13: NO), the CPU 51 determines whether the interpreted control command is G100 or M06 (S14). If the interpreted control command is neither G100 nor M06 (S14: NO), the CPU 51 executes the interpreted control command (S15). The CPU 51 moves to the next block (S19) and returns to S12 to repeat the above process. If the control command in the interpreted block is G100 or M06 (S14: YES), the CPU 51 executes the forward path execution process (S16).

The forward path execution process will be described with reference to Figures 9 and 10. When the forward path execution process is performed, the spindle 7 is located at the machining end position Q1 where machining of the workpiece W is completed. As shown in Figure 9, the CPU 51 calculates the coordinate value of the first return position A1 based on the Z-axis coordinate value of the first return position A1, the coordinate value of the machining end position Q1, and the tool length offset value included in the control command (S21). The CPU 51 calculates a movement command for moving the spindle 7 from the machining end position Q1 to the first return position A1 based on the coordinate value of the machining end position Q1 and the coordinate value of the first return position A1 (S22). When moving the spindle 7, the CPU 51 outputs drive instructions as movement commands to the X-axis motor 11A, Z-axis motor 12A, and Y-axis motor 13A, which are servo motors, at each sampling period. When the servo motors receive a movement command, they begin accelerating, continue accelerating while the movement command continues, and maintain that speed when they reach maximum speed. When the movement command ends, they begin deceleration using a moving average filter and stop after deceleration. For this reason, the movement distance of the spindle 7 must be calculated taking into account the acceleration and deceleration of the servo motor. The CPU 51 calculates the number of sampling periods for which movement commands will continue to be output so that the distance the spindle 7 moves as the servo motor accelerates, drives at maximum speed, and decelerates and stops matches the distance between the machining end position Q1 and the first return position A1. The CPU 51 distributes and generates movement commands from the machining end position Q1 to the calculated number of sampling periods.

The first return position A1 is in the positive direction of the Z axis relative to the machining end position Q1. The CPU 51 executes steps S24 to S27 until it has output all distributed movement commands (S23: NO). The CPU 51 outputs a command to open the shutter 103. This command is output only on the first execution. The shutter motor 34 is driven, and starts opening the shutter 103 (S24). The CPU 51 outputs a command to start orientation. This command is output only on the first execution. The spindle motor 26 is driven, and starts rotating the spindle 7, pointing the rotational position of the spindle 7 toward the orientation position (S26). The orientation position is the position where the rotational position of the spindle 7 is 0° or 180°, and where the orientation of the spindle 7 and the tool 91 are aligned when the tool holder 90 is attached to the tool mounting hole 40 of the spindle 7. Orientation refers to the operation of rotating the spindle 7 and aligning the rotational position (rotation angle) of the spindle 7 with the orientation position. The CPU 51 outputs movement commands distributed in the Z-axis direction for each sampling period (S27). The spindle 7 moves in the positive direction of the Z-axis from the machining start position Q2 and begins moving backward to the first return position A1. When the CPU 51 has completed outputting all distributed movement commands (S23: YES), it proceeds to S28. The spindle 7 is moving to the first return position A1, and because distribution of the movement commands has been completed, it is about to start slowing down its movement speed.

The CPU 51 calculates the coordinate values of the ATC preparation position B (S28). The coordinate values of the ATC preparation position B are calculated from predefined default coordinate values and device-specific parameters. The CPU 51 calculates a movement command for moving the spindle 7 from the first return position A1 to the ATC preparation position B based on the coordinate values of the first return position A1 and the coordinate values of the ATC preparation position B (S29). The CPU 51 distributes and generates movement commands in each of the X-axis, Z-axis, and Y-axis directions so that the movement distance of the spindle 7, taking acceleration and deceleration into account, matches the distance between the first return position A1 and the ATC preparation position B.

The CPU 51 executes steps S32 to S34 until it has completed outputting all distributed movement commands in the X-, Z-, and Y-axis directions (S31: NO). The CPU 51 outputs the distributed movement commands for the Z-axis direction at each sampling period (S32). As a result, the movement command in the Z-axis direction from first return position A1 to ATC preparation position B is output consecutively following the movement command in the Z-axis direction from machining end position Q1 to first return position A1, for which distribution has just been completed. The main spindle 7 maintains maximum speed and continues movement toward ATC preparation position B without beginning to decelerate the movement speed toward first return position A1. In other words, the main spindle 7 continues movement in the Z-axis direction from machining end position Q1 to ATC preparation position B without performing an in-position check at first return position A1.

The output of movement commands in the Z-axis direction begins before the spindle 7 passes the first return position A1 in the Z-axis direction (S33: NO). The positions of the spindle 7 in the X-axis, Z-axis, and Y-axis directions are constantly monitored based on feedback control of the drive circuits 62-64 by encoders 11B, 12B, and 13B. When the spindle 7 passes the first return position A1 in the Z-axis direction (S33: YES), the CPU 51 outputs the distributed movement commands in the X-axis and Y-axis directions at each sampling period (S34). When the CPU 51 has completed output of all distributed movement commands in the X-axis, Z-axis, and Y-axis directions (S31: YES), it proceeds to S41. The spindle 7 is moving to the ATC preparation position B, and since distribution of movement commands has been completed, particularly in the Y-axis direction, the movement speed is about to begin slowing down.

As shown in FIG. 10, the CPU 51 calculates the coordinate values of ATC position C (S41). The coordinate values of ATC position C are calculated from predefined default coordinate values and device-specific parameters. Based on the coordinate values of ATC preparation position B and ATC position C, the CPU 51 calculates a movement command for moving the spindle 7 from ATC preparation position B to ATC position C (S42). Relative to ATC preparation position B, ATC position C is in the positive direction of the Y axis. The CPU 51 distributes and generates movement commands in the Y axis direction so that the movement distance of the spindle 7, taking acceleration and deceleration into account, matches the distance between ATC preparation position B and ATC position C.

The CPU 51 executes the processes of S44 to S49 until it has completed outputting all distributed movement commands (S43: NO). If the CPU 51 determines, based on feedback control, that the spindle 7 has not reached the ATC preparation position B in the Z-axis direction (S44: NO), it returns the process to S43. If the CPU 51 determines, based on feedback control, that the spindle 7 has not reached the ATC preparation position B in the X-axis direction (S46: NO), it returns the process to S43. If the CPU 51 determines, based on feedback control, that the shutter 103 has not yet been opened (S47: NO), it returns the process to S43. If the CPU 51 determines, based on feedback control, that the rotational position of the spindle 7 is not at the orient position (S48: NO), it returns the process to S43.

If the spindle 7 has reached the ATC preparation position B in both the Z and X axes (S44: YES, S46: YES), the shutter 103 has been opened (S47: YES), and the spindle 7 is in the orientation position (S48: YES), the CPU 51 outputs the distributed movement command in the Y axis direction for each sampling period (S49). Here, if the spindle 7 has reached the ATC preparation position B in both the Z and X axes before reaching the ATC preparation position B in the Y axis direction, is in the orientation position, and the shutter 103 has been opened, the movement command from the ATC preparation position B to the ATC position C in the Y axis direction is output consecutively following the movement command from the first return position A1 to the ATC preparation position B in the Y axis direction. The spindle 7 continues to move toward the ATC position C at maximum speed without starting to decelerate its movement speed toward the ATC preparation position B in the Y axis direction. That is, the spindle 7 continues to move in the Y-axis direction from the first return position A1 to the ATC position C without performing an in-position check at the ATC preparation position B. When the CPU 51 has completed outputting all movement commands distributed in the Y-axis direction (S43: YES), it proceeds to S51.

The CPU 51 moves the spindle 7 from the ATC preparation position B in the positive direction of the Y axis, and raises it to the ATC position C. The ATC position C corresponds to the pot position (storage position) of the grip arm 35 directly below the tool magazine 31. Therefore, when the spindle 7 rises to the ATC position C, the tool holder 90 holding the tool 91 attached to the spindle 7 engages with the empty pot from below.

The CPU 51 calculates the coordinate values of the ATC origin position D (S51). The coordinate values of the ATC origin position D are calculated from predefined default coordinate values and device-specific parameters. Based on the coordinate values of the ATC position C and the coordinate values of the ATC origin position D, the CPU 51 calculates a movement command for moving the spindle 7 from the ATC position C to the ATC origin position D (S52). The ATC origin position D is in the positive direction of the Z axis relative to the ATC position C. The CPU 51 distributes and generates a movement command in the Z axis direction so that the movement distance of the spindle 7, taking acceleration and deceleration into account, matches the distance between the ATC position C and the ATC origin position D.

The CPU 51 executes the processes of S54 to S56 until it has completed outputting all distributed movement commands (S53: NO). If the CPU 51 determines, based on feedback control, that the spindle 7 has not reached ATC position C in the Y-axis direction (S54: NO), it returns the process to S53. If the spindle 7 has reached ATC position C in the Y-axis direction (S54: YES), the CPU 51 outputs distributed movement commands in the Z-axis direction for each sampling period (S56). When the CPU 51 has completed outputting all distributed movement commands in the Z-axis direction (S53: YES), it proceeds to S57. The tool holder 90 holding the tool 91 is gripped by the grip arm 35, and is therefore withdrawn from the spindle 7 as the spindle 7 moves in the Z+ direction. Based on feedback control, the CPU 51 waits for the spindle 7 to reach the ATC origin position D in the Z-axis direction (S57: NO), and if it does reach it (S57: YES), ends the forward path execution process.

Returning to the flow of Figure 8, the CPU 51 performs processing to prepare the next tool 92 to be loaded (S17). The machine tool 1 rotates the tool magazine 31 and positions the grip arm 35 holding the next tool 92 directly below the tool magazine 31. Next, the CPU 51 executes the return pass execution processing (S18).

The return path execution process will be described with reference to Figures 11 and 12. When the return path execution process is performed, the spindle 7 is located at ATC origin position D. As shown in Figure 11, the CPU 51 calculates the coordinate values of ATC position C (S61). Based on the calculated coordinate values, the CPU 51 calculates a movement command for moving the spindle 7 from ATC origin position D to ATC position C (S62). ATC position C is located in the negative direction of the Z axis relative to ATC origin position D, and the CPU 51 distributes and generates movement commands in the Z axis direction. The CPU 51 outputs distributed movement commands in the Z axis direction at each sampling period (S64) until it has completed output of all distributed movement commands (S63: YES). When the CPU 51 has completed output of all distributed movement commands (S63: YES), it waits for the spindle 7 to reach ATC position C in the Z axis direction based on feedback control (S66: NO).

When the spindle 7 reaches ATC position C in the Z-axis direction (S66: YES), the CPU 51 calculates the coordinate value of ATC preparation position B (S67). Based on the calculated coordinate value, the CPU 51 calculates a movement command for moving the spindle 7 from ATC position C to ATC preparation position B (S68). ATC preparation position B is located in the negative Y-axis direction relative to ATC position C, and the CPU 51 distributes and generates movement commands in the Y-axis direction. The CPU 51 outputs the distributed movement commands in the Y-axis direction every sampling period (S71) until it has completed outputting all distributed movement commands (S69: NO). When the CPU 51 has completed outputting all distributed movement commands (S69: YES), the process proceeds to S81. The spindle 7 is moving in the negative Y-axis direction to ATC preparation position B, and because distribution of the movement commands has been completed, it is about to start decelerating its movement speed.

As shown in FIG. 12, the CPU 51 calculates the coordinate value of the second return position A2 based on the Z-axis coordinate value of the second return position A2, the coordinate value of the machining start position Q2, and the tool length offset value included in the control command (S81). Based on the calculated coordinate values, the CPU 51 calculates a movement command for moving the spindle 7 from the ATC preparation position B to the second return position A2 (S82). The CPU 51 distributes and generates movement commands in the X-axis, Z-axis, and Y-axis directions so that the movement distance of the spindle 7, taking acceleration and deceleration into account, matches the distance between the ATC preparation position B and the second return position A2.

The CPU 51 executes steps S84 through S88 until it has completed outputting all distributed movement commands in the X-, Z-, and Y-axis directions (S83: NO). The CPU 51 outputs the distributed movement commands for the Y-axis direction at each sampling period (S84). As a result, the movement command from ATC preparation position B to second return position A2 in the Y-axis direction is output consecutively following the movement command from ATC position C to ATC preparation position B in the Y-axis direction for which distribution has been completed. The spindle 7 maintains maximum speed and continues movement toward second return position A2 in the Y-axis direction without starting to decelerate the movement speed toward ATC preparation position B. In other words, the spindle 7 continues movement from ATC position C to second return position A2 in the Z-axis direction without performing an in-position check at ATC preparation position B.

The output of the movement command in the Y-axis direction begins before the spindle 7 passes the ATC preparation position B in the Y-axis direction (S86: NO). Based on feedback control, when the spindle 7 passes the ATC preparation position B in the Y-axis direction (S86: YES), the CPU 51 outputs a command to close the shutter 103. Note that this command is output only the first time it is executed. The shutter motor 34 is driven, and the shutter 103 begins to close (S87). The CPU 51 outputs the distributed movement commands in the X-axis and Z-axis directions for each sampling period (S88). When the CPU 51 has completed output of all distributed movement commands in the X-axis, Z-axis, and Y-axis directions (S83: YES), the process proceeds to S92. The spindle 7 is moving to the second return position A2, and since distribution of the movement command has been completed, particularly in the Z-axis direction, the movement speed is about to begin slowing down.

The CPU 51 calculates the coordinate values of the machining start position Q2 (S92). The coordinate values of the machining start position Q2 are included in the control command. Based on the coordinate values, the CPU 51 calculates a movement command to move the spindle 7 from the second return position A2 to the machining start position Q2 (S93). The machining start position Q2 is in the negative direction of the Z axis relative to the second return position A2. The CPU 51 distributes and generates movement commands in the Z axis direction so that the movement distance of the spindle 7, taking acceleration and deceleration into account, matches the distance between the second return position A2 and the machining start position Q2.

The CPU 51 executes the processes of S96 to S98 until it has completed outputting all distributed movement commands (S94: NO). If the CPU 51 determines, based on feedback control, that the spindle 7 has not reached the second return position A2 in the X-axis direction (S96: NO), it returns the process to S94. If the CPU 51 determines, based on feedback control, that the spindle 7 has not reached the second return position A2 in the Y-axis direction (S97: NO), it returns the process to S94.

If the spindle 7 has reached the second return position A2 in both the X and Y axes (S96: YES, S97: YES), the CPU 51 outputs the distributed movement command for the Z axis direction at each sampling period (S98). If the spindle 7 reaches the second return position A2 in both the X and Y axes before reaching the second return position A2 in the Z axis direction, the movement command from the second return position A2 in the Z axis direction to the machining start position Q2 is output consecutively following the movement command from the ATC preparation position B to the second return position A2 in the Z axis direction. The spindle 7 maintains maximum speed and continues moving toward the machining start position Q2 without starting to decelerate its movement speed toward the second return position A2 in the Z axis direction. That is, the spindle 7 continues moving from the ATC preparation position B to the machining start position Q2 in the Z axis direction without performing an in-position check at the second return position A2. When the CPU 51 has completed outputting all of the movement commands distributed in the Z-axis direction (S94: YES), it proceeds to S99. Based on feedback control, the CPU 51 waits for the spindle 7 to reach the machining start position Q2 in the Z-axis direction (S99: NO), and when it has reached the position (S99: YES), it ends the return path execution process.

Returning to the flow in Figure 8, the CPU 51 has completed the series of tool change operations for G100, so it moves on to the next block (S19) and interprets that next block (S12). If the interpreted next block is M30 (S13: YES), the CPU 51 terminates this processing.

As explained above, when a movement command toward ATC preparation position B is output for movement of the spindle 7 in the + direction of the Y axis, the spindle 7 begins to accelerate its movement speed from 0 from the first return position A1 toward ATC preparation position B. Once distribution of the movement command is complete, the spindle 7 typically begins to decelerate its movement speed so as to stop movement at ATC preparation position B. A movement command toward ATC position C is immediately issued if the spindle 7 has reached ATC preparation position B in the X axis direction when distribution of the movement command toward ATC preparation position B is complete. In other words, a movement command in the Y axis direction toward ATC preparation position B and a movement command in the Y axis direction toward ATC position C are output consecutively as long as the spindle 7 has reached ATC preparation position B in the X axis direction. Therefore, the spindle 7 continues to move toward the next ATC position C without decelerating its movement speed in the Y axis direction toward ATC preparation position B. For example, compared to when distribution of a movement command toward ATC preparation position B is completed and an in-position check confirms that the spindle 7 has reached ATC preparation position B before outputting a movement command toward ATC position C, the spindle 7 can move more quickly in the Y-axis direction from first return position A1 to ATC position C. Therefore, the numerical control device 50 can shorten the tool change time.

When a movement command toward first return position A1 is output for movement of the spindle 7 in the +Z direction, the spindle 7 begins accelerating its movement speed from 0 from the machining end position Q1 toward first return position A1. Once the output of the movement command is complete, the spindle 7 typically begins decelerating its movement speed so as to stop movement at first return position A1. The movement command toward ATC preparation position B in the Z direction is output immediately after the output of the movement command toward first return position A1 is completed. In other words, the movement command toward first return position A1 in the Z direction and the movement command toward ATC preparation position B are output consecutively. Therefore, the spindle 7 continues moving toward the next ATC preparation position B without decelerating its movement speed toward first return position A1. For example, compared to when outputting a movement command toward the first return position A1 is completed, and an in-position check is performed to confirm that the spindle 7 has reached first return position A1 before outputting a movement command toward the ATC preparation position B, the spindle 7 can move more quickly in the Z-axis direction from the machining end position Q1 to the ATC preparation position B. Therefore, the numerical control device 50 can shorten the tool change time.

When moving the spindle 7 in the + direction of the Y axis, even if the output of a movement command toward ATC preparation position B is completed, a movement command toward ATC position C will not be output until the spindle 7 reaches ATC preparation position B in the Z axis direction. Therefore, the spindle 7 can reliably move to ATC position C.

When a movement command toward ATC preparation position B is output for movement of the spindle 7 in the negative Y-axis direction, the spindle 7 begins to accelerate its movement speed from 0 from ATC position C toward ATC preparation position B, and once the command output is complete, it typically begins to decelerate its movement speed so as to stop movement at ATC preparation position B. The movement command toward second return position A2 is output as soon as the output of the movement command toward ATC preparation position B is complete. In other words, the movement command toward ATC preparation position B and the movement command toward second return position A2 are output consecutively. Therefore, the spindle 7 does not decelerate its movement speed toward ATC preparation position B, and continues moving toward the next second return position A2. For example, compared to when outputting a movement command toward the ATC preparation position B is completed, and an in-position check is performed to confirm that the spindle 7 has reached the ATC preparation position B before outputting a movement command toward the second return position A2, the spindle 7 can move from the ATC position C to the second return position A2 in the Y-axis direction more quickly. Therefore, the numerical control device 50 can shorten the tool change time.

When a movement command toward the second return position A2 is output for the spindle 7 moving in the negative Z-axis direction, the spindle 7 begins accelerating its movement speed from 0 as it moves from the ATC preparation position B toward the second return position A2. Once the command output is complete, the spindle 7 typically begins decelerating its movement speed so as to stop moving at the second return position A2. The movement command toward the machining start position Q2 is output immediately if the spindle 7 has reached the second return position A2 in the X- and Y-axis directions when the movement command toward the second return position A2 is complete. In other words, the movement command toward the second return position A2 and the movement command toward the machining start position Q2 are output consecutively as long as the spindle 7 has reached the second return position A2 in the X- and Y-axis directions. Therefore, the spindle 7 continues moving toward the next machining start position Q2 without decelerating its movement speed toward the second return position A2. For example, compared to when outputting a movement command toward the second return position A2 is completed, and an in-position check is performed to confirm that the spindle 7 has reached the second return position A2 before outputting a movement command toward the machining start position Q2, the spindle 7 can move from the ATC preparation position B to the machining start position Q2 in the Z-axis direction more quickly. Therefore, the numerical control device 50 can shorten the tool change time.

The numerical control device 50 can confirm that the shutter 103 of the magazine cover 10 is in the open state before outputting a movement command toward ATC position C in the +Y axis direction. Therefore, the spindle 7 can reliably move to ATC position C.

The numerical control device 50 can confirm that the rotational position of the spindle 7 is at the orient position before outputting a movement command toward ATC position C in the positive Y-axis direction. Therefore, the spindle 7 moves to ATC position C, ensuring that the attached tool can be securely gripped by the gripping arm.

In the above description, the tool magazine 31 is an example of a "magazine" in the present invention. The tool 91 is an example of an "attached tool" in the present invention. The machining end position Q1 is an example of an "end position" in the present invention. The Z-axis direction is an example of an "axial direction" in the present invention. The grip arm 35 is an example of a "storage section" in the present invention. The ATC position C is an example of a "storage position" in the present invention. The ATC preparation position B is an example of a "preparation position" in the present invention. The ATC origin position D is an example of a "punching position" in the present invention. The CPU 51 that executes the forward path execution process is an example of a "storage control section" in the present invention. The Y-axis direction is an example of a "first orthogonal direction" in the present invention. The X-axis direction is an example of a "second orthogonal direction" in the present invention. In feedback control based on the detection signals of encoders 11B, 12B, and 13B, drive circuits 62, 63, and 64 output to numerical control device 50 the position of spindle 7 in the X-axis, Z-axis, and Y-axis directions corresponding to the rotational positions of the drive axes of X-axis motor 11A, Z-axis motor 12A, and Y-axis motor 13A. These drive circuits are an example of a "position detection unit" of the present invention. CPU 51 that executes the process of S32 is an example of a "first instruction unit" of the present invention. CPU 51 that executes the process of S34 is an example of a "second instruction unit" of the present invention. CPU 51 that executes the process of S49 is an example of a "third instruction unit" of the present invention. CPU 51 that executes the process of S46 is an example of a "first determination unit" of the present invention.

The CPU 51 that executes the process of S27 is an example of the "fourth instruction unit" of the present invention. The CPU 51 that executes the process of S33 is an example of the "second judgment unit" of the present invention. The CPU 51 that executes the process of S44 is an example of the "third judgment unit" of the present invention. The next tool 92 is an example of the "unmounted tool" of the present invention. The machining start position Q2 is an example of the "start position" of the present invention. The CPU 51 that executes the return path execution process corresponds to the "mounting control unit" of the present invention. The CPU 51 that executes the process of S71 is an example of the "fifth instruction unit" of the present invention. The CPU 51 that executes the process of S84 is an example of the "sixth instruction unit" of the present invention. The CPU 51 that executes the process of S88 is an example of the "seventh instruction unit" of the present invention. The CPU 51 that executes the process of S86 is an example of the "fourth judgment unit" of the present invention. The CPU 51 that executes the process of S98 is an example of the "eighth instruction unit" of the present invention. The CPU 51 that executes the processes of S96 and S97 is an example of the "fifth judgment unit" of the present invention. The magazine cover 10 is an example of a "cover" in the present invention. The shutter motor 34 is an example of an "open/close drive unit" in the present invention. In feedback control based on the detection signal of the encoder 34A, the drive circuit 66 outputs the open/close state of the shutter 103 corresponding to the rotational position of the drive shaft of the shutter motor 34 to the numerical control device 50. This is an example of an "open/close detection unit" in the present invention. The CPU 51 that executes the process of S24 is an example of a "ninth instruction unit." The CPU 51 that executes the process of S47 is an example of a "sixth determination unit." In feedback control based on the detection signal of the encoder 26A, the drive circuit 61 that outputs the rotation angle of the main shaft 7 corresponding to the rotational position of the drive shaft of the main shaft motor 26 to the numerical control device 50 is an example of a "rotation detection unit" in the present invention. The CPU 51 that executes the process of S26 is an example of a "tenth instruction unit." The CPU 51 that executes the process of S48 is an example of a "seventh determination unit."

The present invention is not limited to the above embodiment and various modifications can be made. The machine tool 1 is a horizontal machine tool, but it may also be a vertical machine tool in which the axial direction of the spindle is vertical. The machine tool 1 moves the column 5 in the X-axis direction, the spindle 7 in the Z-axis direction, and the spindle 7 in the Y-axis direction, thereby moving the workpiece W and tool 91 relatively in the X-axis, Y-axis, and Z-axis, but other structures are also possible. For example, the column 5 may be moved in two axes, the X-axis and the Z-axis, and the spindle 7 may be moved in the Y-axis direction.

The Z-axis coordinate values of the first return position A1 and the second return position A2 may not be included in the tool change command, but may be specified by user-settable parameters. When positioning the spindle 7 to the first return position A1 and the second return position A2, the CPU 51 may operate without applying a tool length offset. While the machine tool 1 opens and closes the shutter 103 of the magazine cover 10 by driving the shutter motor 34, it may also be opened and closed by driving an air cylinder (not shown). In this case, the CPU 51 of the numerical control device 50 may perform determination processing in S47 based on the results of detection of the open/closed state of the shutter 103 by an open/close sensor.

When the CPU 51 outputs a command to move from the machining start position Q2 in the Z-axis direction to the first return position A1 in S27, it outputs a command to open the shutter 103 in S24, but this timing is not limited. For example, when the CPU 51 outputs a command to move from the first return position A1 in the Z-axis direction to the ATC preparation position B in S32, it may output a command to open the shutter 103. Alternatively, when the CPU 51 outputs a command to move from the first return position A1 in the X-axis and Y-axis directions to the ATC preparation position B in S34, it may output a command to open the shutter 103.

When the CPU 51 outputs a command to move from the machining start position Q2 in the Z-axis direction to the first return position A1 in S27, it outputs a command to start orienting the spindle 7 in S26, but this timing is not limited to this. For example, the CPU 51 may output a command to start orienting the spindle 7 when it outputs a command to move from the first return position A1 in the Z-axis direction to the ATC preparation position B in S32. Alternatively, the CPU 51 may output a command to start orienting the spindle 7 when it outputs a command to move from the first return position A1 in the X-axis and Y-axis directions to the ATC preparation position B in S34.

1 Machine tool 7 Spindle 10 Magazine cover 11B, 12B, 13B, 26A, 34A Encoder 30 ATC device 31 Tool magazine 34 Shutter motor 35 Grip arm 50 Numerical control device 51 CPU
91 Tool 92 Next tool 102 Opening 103 Shutter A1 First return position A2 Second return position B ATC preparation position C ATC position D ATC origin position Q1 Machining end position Q2 Machining start position W Workpiece

Claims (11)

A numerical control device for controlling a machine tool having a spindle on which a tool is attached, a magazine having a plurality of storage sections for storing the tools, and a table on which a workpiece is fixed,
From the end position which is the position of the spindle when the processing of the workpiece is completed,
a first return position that is a position away from the end position in the axial direction of the spindle, and in which the tool attached to the spindle does not collide with the workpiece;
a storage position in which the attached tool is stored in the storage section of the magazine;
and a preparation position which is between the first return position and the storage position and is a position away from the storage position in a first orthogonal direction which is orthogonal to the axial direction, after the spindle passes through the first return position, the preparation position, and the storage position in this order,
a storage control unit that moves the spindle to a removal position that is located in a direction away from the magazine along the axial direction relative to the storage position and in which the attached tool remains in the storage section and is removed from the spindle;
The machine tool includes at least
a position of the main shaft in the axial direction;
a position detection unit that detects a position of the main shaft in a second orthogonal direction that is orthogonal to the axial direction and orthogonal to the first orthogonal direction,
The storage control unit
a first instruction unit that instructs movement of the spindle in the axial direction from the first return position to the preparation position;
a second instruction unit that instructs movement of the spindle from the first return position to the preparation position in the first orthogonal direction and the second orthogonal direction;
a third instruction unit that instructs movement of the spindle from the preparation position to the storage position in the first orthogonal direction;
a first determination unit that determines whether the spindle has reached the preparation position in the second orthogonal direction based on a detection result of the position detection unit,
a third instruction unit that starts outputting instructions as soon as the first determination unit determines that the second instruction unit has completed outputting instructions and that the spindle has reached the preparation position in the second orthogonal direction. The storage control unit
a fourth instruction unit that instructs movement of the main shaft from the end position to the first return position in the axial direction;
a second determination unit that determines whether the spindle has reached the first return position in the axial direction based on a detection result of the position detection unit,
Upon completion of the output of the instruction by the fourth instruction unit, start output of the instruction by the first instruction unit;
2. The numerical control device according to claim 1, wherein the second determining unit starts outputting an instruction from the second indicating unit when the second determining unit determines that the spindle has reached the first return position in the axial direction. The storage control unit
a third determination unit that determines whether the spindle has reached the preparation position in the axial direction based on a detection result of the position detection unit,
2. The numerical control device according to claim 1, wherein the output of an instruction by the third instruction unit is started as soon as the second instruction unit has completed outputting an instruction and the first determination unit has determined that the spindle has reached the preparation position in the second orthogonal direction, and the third determination unit has determined that the spindle has reached the preparation position in the axial direction. The storage control unit
a third determination unit that determines whether the spindle has reached the preparation position in the axial direction based on a detection result of the position detection unit,
3. The numerical control device according to claim 2, wherein the output of an instruction by the third instruction unit is started as soon as the output of an instruction by the second instruction unit is completed and the first determination unit determines that the spindle has reached the preparation position in the second orthogonal direction, and the third determination unit determines that the spindle has reached the preparation position in the axial direction. In a state where the storage section for storing an unattached tool that is a tool to be used in the next processing among the plurality of storage sections of the magazine is arranged at a position corresponding to the storage position,
and a mounting control unit that moves the spindle from the extraction position to the storage position and then to the preparation position, and then moves the spindle to a second return position that is a position away from a start position, which is a position of the spindle at the start of machining of the workpiece with the unattached tool, in the axial direction and where the unattached tool does not collide with the workpiece, and then moves the spindle to the start position.
The position detection unit of the machine tool further detects the position of the spindle in the first orthogonal direction,
The mounting control unit
a fifth instruction unit that instructs movement of the spindle from the stored position to the preparation position in the first orthogonal direction;
a sixth instruction unit that instructs movement of the spindle from the preparation position to the second return position in the first orthogonal direction;
a seventh instruction unit that instructs movement of the spindle from the preparation position to the second return position in the axial direction and the second orthogonal direction;
a fourth determination unit that determines whether the spindle has reached the preparation position in the first orthogonal direction based on a detection result of the position detection unit,
immediately after the fifth instruction unit has completed outputting instructions, the sixth instruction unit starts outputting instructions;
5. The numerical control device according to claim 3, wherein the seventh instruction unit starts outputting an instruction as soon as the fourth determination unit determines that the spindle has reached the preparation position in the first orthogonal direction. The mounting control unit
an eighth instruction unit that instructs movement of the main spindle from the second return position to the start position in the axial direction;
a fifth determination unit that determines whether the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction based on a detection result of the position detection unit,
6. The numerical control device according to claim 5, wherein the output of an instruction by the eighth instruction unit is started as soon as the fifth determination unit determines that the output of an instruction by the seventh instruction unit is completed and the spindle has reached the second return position in the first orthogonal direction and the second orthogonal direction. The machine tool comprises:
a cover that covers the periphery of the magazine;
an opening formed in the cover, the opening being between the storage position located inside the cover and the preparation position located outside the cover, through which the main shaft can pass;
a shutter that opens and closes the opening;
an opening/closing drive unit that opens and closes the shutter;
an open/close detection unit that detects the open/close state of the shutter,
The storage control unit
a ninth instruction unit that instructs the opening/closing drive unit to open the shutter;
a sixth determination unit that determines whether the shutter is in an open state based on a detection result of the open/close detection unit,
instructing the ninth instruction unit to open the shutter when output of an instruction by any one of the first instruction unit, the second instruction unit, or the fourth instruction unit is started;
5. The numerical control device according to claim 4, further comprising: a third instruction unit that starts outputting an instruction as soon as the sixth determination unit determines that the shutter is in the open state. the machine tool includes a rotation detection unit that detects a rotation position of the spindle,
The storage control unit
a tenth indicator that indicates rotation of the spindle toward an orient position that is a rotation position of the spindle at which the attached tool can be stored in the storage section; and
a seventh determination unit that determines whether the rotation position of the spindle is at the orient position based on the detection result of the rotation detection unit,
When output of an instruction by any one of the first instruction unit, the second instruction unit, or the fourth instruction unit is started, an instruction is given to rotate the spindle toward the orient position by the tenth instruction unit,
5. The numerical control device according to claim 4, further comprising: a third instruction unit that starts outputting an instruction as soon as the seventh determination unit determines that the rotational position of the spindle is at the orient position. In order to control a machine tool having a spindle on which a tool is attached, a magazine having a plurality of storage sections for storing the tools, and a table on which a workpiece is fixed,
From the end position which is the position of the spindle when the processing of the workpiece is completed,
a first return position that is a position away from the end position in the axial direction of the spindle, and in which the tool attached to the spindle does not collide with the workpiece;
a storage position in which the attached tool is stored in the storage section of the magazine;
and a preparation position which is between the first return position and the storage position and is a position away from the storage position in a first orthogonal direction which is orthogonal to the axial direction, after the spindle passes through the first return position, the preparation position, and the storage position in this order,
a control method for a numerical control device, comprising: a storage control step of moving the spindle to a removal position where the attached tool remains in the storage section and is removed from the spindle, the removal position being located in a direction away from the magazine along the axial direction with respect to the storage position,
The storage control step includes:
a first determination step of determining whether or not the spindle has reached the preparation position in the second orthogonal direction based on detection results of a position detection unit that is provided in the machine tool and that detects at least a position of the spindle in the axial direction and a position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and also orthogonal to the first orthogonal direction;
a first instruction step of instructing movement of the spindle in the axial direction from the first return position to the preparation position;
a second instruction step of instructing movement of the spindle from the first return position to the preparation position in the first orthogonal direction and the second orthogonal direction;
a third instruction step of instructing movement of the spindle from the preparation position to the storage position in the first orthogonal direction,
a control method characterized in that output of an instruction by the third instructing step is started as soon as output of an instruction by the second instructing step is completed and the first judging step judges that the spindle has reached the preparation position in the second orthogonal direction. In order to control a machine tool having a spindle on which a tool is attached, a magazine having a plurality of storage sections for storing the tools, and a table on which a workpiece is fixed,
From the end position which is the position of the spindle when the processing of the workpiece is completed,
a first return position that is a position away from the end position in the axial direction of the spindle, and in which the tool attached to the spindle does not collide with the workpiece;
a storage position in which the attached tool is stored in the storage section of the magazine;
and a preparation position which is between the first return position and the storage position and is a position away from the storage position in a first orthogonal direction which is orthogonal to the axial direction, after the spindle passes through the first return position, the preparation position, and the storage position in this order,
a storage control step of moving the spindle to a removal position where the attached tool remains in the storage section and is removed from the spindle, the program causing a numerical control device to function, the program comprising:
On the computer,
In the storage control step,
a first determination step of determining whether or not the spindle has reached the preparation position in the second orthogonal direction based on detection results of a position detection unit that is provided in the machine tool and that detects at least a position of the spindle in the axial direction and a position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and also orthogonal to the first orthogonal direction;
a first instruction step of instructing movement of the spindle in the axial direction from the first return position to the preparation position;
a second instruction step of instructing movement of the spindle from the first return position to the preparation position in the first orthogonal direction and the second orthogonal direction;
a third instruction step of instructing movement of the spindle from the preparation position to the storage position in the first orthogonal direction,
a program for starting output of an instruction in the third instructing step as soon as output of an instruction in the second instructing step is completed and as soon as the first judging step judges that the spindle has reached the preparation position in the second orthogonal direction. In order to control a machine tool having a spindle on which a tool is attached, a magazine having a plurality of storage sections for storing the tools, and a table on which a workpiece is fixed,
From the end position which is the position of the spindle when the processing of the workpiece is completed,
a first return position that is a position away from the end position in the axial direction of the spindle, and in which the tool attached to the spindle does not collide with the workpiece;
a storage position in which the attached tool is stored in the storage section of the magazine;
and a preparation position which is between the first return position and the storage position and is a position away from the storage position in a first orthogonal direction which is orthogonal to the axial direction, after the spindle passes through the first return position, the preparation position, and the storage position in this order,
a program for controlling a numerical control device that causes a computer to execute a storage control step of moving the spindle to a removal position that is positioned in a direction away from the magazine along the axial direction with respect to the storage position, and in which the attached tool remains in the storage section and is removed from the spindle,
On the computer,
In the storage control step,
a first determination step of determining whether or not the spindle has reached the preparation position in the second orthogonal direction based on detection results of a position detection unit that is provided in the machine tool and that detects at least a position of the spindle in the axial direction and a position of the spindle in a second orthogonal direction that is orthogonal to the axial direction and also orthogonal to the first orthogonal direction;
a first instruction step of instructing movement of the spindle in the axial direction from the first return position to the preparation position;
a second instruction step of instructing movement of the spindle from the first return position to the preparation position in the first orthogonal direction and the second orthogonal direction;
a third instruction step of instructing movement of the spindle from the preparation position to the storage position in the first orthogonal direction,
a storage medium storing a program for starting output of an instruction in the third instructing step as soon as output of an instruction in the second instructing step is completed and the first judging step judges that the spindle has reached the preparation position in the second orthogonal direction.