JP3643098B2 - Numerical controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a numerical control device that controls a processing machine that performs processing by rotating a workpiece.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a machine tool that has at least one linear movement axis and a table rotation movement axis, and further has one axis for tool head rotation or one axis for table rotation. For example, the table 1 as shown in FIG. 1 is driven in the X and Y axis directions orthogonal to each other, the tool 2 is driven in the Z axis direction orthogonal to the X and Y axes, and the tool is further rotated by the rotation axis A around the X axis. A 5-axis processing machine is known in which the table 1 is controlled by the rotation axis C around the Z axis and the workpiece 3 mounted and fixed on the table 1 is processed simultaneously with the rotation control of 2.
[0003]
As shown in FIG. 2, the tool 2 is driven in the orthogonal X, Y, and Z axis directions, and the table 1 is rotationally controlled by the rotation axis A around the X axis and the rotation axis C around the Z axis. Also known is a 5-axis processing machine in which a work 3 placed and fixed on 1 is processed by a tool 2.
[0004]
In order to perform an operation in which the tip of the tool 2 moves along an intended path at an intended speed while the rotation axes A and C rotate, conventionally, a minute line segment program is created by a CAM and a command is issued. There was a need to do.
[0005]
For example, in a machine tool having one axis (C axis) for rotating the table 1 as shown in FIG. 3 and one axis (A axis) for rotating the head of the tool 2, the table 1 is rotated as shown in FIG. When cutting the straight line L on the workpiece 3 on the table 1 while changing the tilt angle of the tool 2, it cannot be commanded as a single straight command block, and the following <conventional program command> As shown in the example, it is necessary to divide and command in a large number of blocks such as blocks N301 and N302. In FIG. 3, CO is the center of rotation of the C-axis, CS is the reference position of the C-axis, and the C-axis rotation position commanded by the program is controlled to be positioned at this reference position CS. Is. P is a control point of the tool 2, and this control point P is the rotation center of the tool 2.
<Conventional program command>
N200 G01 G90 XXc0 YYc0 ZZc0 A60.0 C30.0;
N301 XXc1 YYc1 ZZc1 A45.0 C90.0;
N302 XXc2 YYc2 ZZc2 A30.0 C150.0;
G01 is a cutting feed command, and G90 is an absolute command. With this program, each axis of the machine tool operates as shown in FIG. FIG. 5A shows the positioning position to the position of X axis = Xc0, Y axis = Yc0, Z axis = Zc0, A axis = 60 degrees, C axis = 30 degrees by the first block “N200”. This is the starting point of processing by the second block “N301”. FIG. 5B shows the end point of the second block “N301” and the start point of the third block “N301”. In accordance with the machining command of the second block “N301”, the cutting is performed linearly as shown by the solid line. FIG. 5C shows the end point of the third block “N301”, and the straight line L is cut according to the commands of the second and third blocks.
[0006]
However, if the machining of the straight line L is divided into about two blocks in this way, the straight line L cannot be cut with high accuracy. In fact, in order to perform machining with high accuracy, it is necessary to divide into a large number of blocks and command them. is there.
[0007]
FIG. 4 is a diagram drawn with the C-axis fixed for convenience. Actually, the C axis operates while rotating. 4 and 5 are views seen from the Z-axis + direction.
In the above description, a machine tool having one axis (C) for rotating the table and one axis (A) for rotating the tool head is described. However, other than A and C, it has two axes for rotating the table and rotating the table. The same applies to machine tools.
[0008]
[Problems to be solved by the invention]
As described above, in a machine tool having at least a table rotation axis, such as a machine tool having one axis for table rotation and one axis for tool head rotation, or two axes for table rotation, those rotation axes are In order to perform an operation of moving the tool tip at a commanded speed while rotating at a commanded speed, it is necessary to create and command a minute line segment program by the CAM. as a result,
(1). A CAM device is required.
(2). Since it becomes a command of many minute line segments, the program length becomes long. Therefore, a large capacity storage device is required.
(3). Since the program length becomes long, in the case of DNC operation (operation performed while transferring a program from an external device to a numerical controller (CNC)), it is necessary to transfer the external device to the CNC at high speed.
(4). Since there are many minute line commands, it takes time for the CNC to analyze the program, and smooth machining may not be possible.
(5). When the tool length is changed, it needs to be recreated from the program by CAM, which takes time.
There is a problem.
[0009]
Accordingly, the present invention is a numerical control device for a processing machine including a rotary shaft that drives a table or the like that holds a workpiece, solves the above-described problems, makes it easy to create a processing program, and the length of the processing program An object of the present invention is to provide a numerical control device that is short and can easily cope with a change in tool length.
[0010]
[Means for Solving the Problems]
The present invention controls a machine tool having at least one linear movement axis and at least one rotation movement axis of the table, and further controls a machine tool having a rotation movement axis for tilting the tool with respect to the table, and is fixed on the table. A numerical control device for continuously machining a workpiece with a tool, the tool direction as a movement path command of the linear movement axis, a relative movement speed command between the workpiece and the tool, and a direction of the tool with respect to the table In the coordinate system defined on the table, a movement command means for giving a movement command for the rotational movement axis to give a command, a means for defining a coordinate system on the table, and a movement path command for the linear movement axis First interpolation means for interpolating based on the relative movement speed command to obtain interpolation position information of the movement path; and Second interpolation means for obtaining interpolation position information of the rotational movement axis by interpolation based on the command and relative movement speed instruction, and correcting the interpolation position information from the first interpolation means based on the interpolation position information of the rotational movement axis A tool specified on the tool by driving the servo motor of each corresponding axis based on the corrected interpolation position information of the moving path and the interpolation position information of the rotational movement axis. It is a numerical control device that controls a tip point to move on a commanded movement path at a commanded speed.
[0011]
The means for correcting the interpolation position information from the first interpolation means is corrected in consideration of the set tool length correction amount and tool radius correction amount.
The tool direction is given as a movement command of the rotational movement position of the rotational movement axis, is given as a direction vector, or is given as a combination of a direction vector and a shift angle.
Further, the movement command means may be configured to command a movement path command for the linear movement axis on the coordinate system, assuming that the coordinate system defined on the table rotates with the table, and does not rotate with the table. In the case of a movement path command for a linear movement axis that is commanded based on a coordinate system that does not rotate with the table, the movement command means may move the movement path of the linear movement axis. There is also provided means for converting the command into a coordinate system that rotates the movement path command of the linear movement axis together with the table.
In addition, the tool tip point is set, the apex of the tool, the center of the hemisphere at the tip of the ball end mill tool, the cutting point on the hemisphere at the tip of the ball end mill tool, the center of the tip surface of the flat end mill tool, the flat end mill Although the cutting point on the tip surface of the tool is set as the tool tip point, any position of these tools and any position of other types of tools can be set as the tool tip point.
Furthermore, the present invention is also applied to a lathe, and a work gripping table that grips a work and is controlled to rotate by a C axis may be used instead of the table.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
First, regarding the principle of the present invention, as shown in FIG. 6, two rotational movements of a C axis that is a rotation axis around the Z axis for table rotation and an A axis that is a rotation axis around the X axis for tool head rotation. I will explain with a machine tool with a shaft. However, the same applies to axis configurations other than the A and C axes and machine tools having two axes for table rotation. The tool tip point Tp is a position designated on the tool, and in the following description, the tool tip point Tp will be described as the apex of the tool.
[0013]
In the tool tip point control mode, the workpiece coordinate system ΣW is stored by storing the origin position (Xw, Yw, Zw) of the workpiece coordinate system ΣW on the preset machine coordinate system ΣM. Further, the tool length correction amount H, which is the length from the rotation center (control point) P of the tool 2 to the tool tip point Tp, is stored.
[0014]
The position of the machining start point of the straight line to be machined, that is, the position (Xm, Ym, Zm) of the machine coordinate system ΣM of the control point P of the machining start point, the machine direction (A, C axis machine coordinate position (Am, Cm) )), The following formulas (1) to (3) are calculated from the tool length correction amount H to obtain the position (Xs, Ys, Zs) of the tool tip point Tp at the start of machining on the workpiece coordinate system ΣW. . For the rotation axis, the machine coordinate position (Am, Cm) is the machining start position (As, Cs). Further, the position (Xm, Ym, Zm, Am, Cm) of this machining start point is set as the position (Xo, Yo, Zo, Ao, Co) after the previous interpolation process used in the interpolation process described later, and the workpiece coordinate system ΣW The tool tip point position (Xs, Ys, Zs) at the start of the above machining is set as the position (Xj, Yj, Zj) after the previous interpolation process. Since the tool direction is a relative direction of the tool 2 with respect to the workpiece, it is represented by rotation angles Am and Cm of the A axis and the C axis representing the rotation of the tool 2 and the rotation of the table 1 (work 3).
Xs = Xm−Xw (1)
Ys = Ym−H * cos (Am) −Yw (2)
Zs = Zm−H * sin (Am) −Zw (3)
The position of the C axis at this time is stored as Cz.
Further, (Xr, Yr, Zr) is stored in a separate parameter as the rotation center position on the machine coordinate system.
[0015]
In the above-described example, the machine coordinate position (Xm, Ym, Zm) of the X, Y, and Z axes of the control point P for starting machining of the linear axis, the tool direction (machine coordinate position (Am, Cm) and the tool length correction amount H, the position (Xs, Ys, Zs) of the tool tip point Tp at the start on the workpiece coordinate system ΣW was obtained. The tool direction (machine coordinate position of the A axis and C axis ( Am, Cm)), the tool compensation vector V is obtained from the tool length compensation amount H, and the position of the control point P at the start of machining on the linear axis (X, Y, Z axis machine coordinate position (Xm, Ym, Zm)) Tool tip point control can also be started by moving the tool tip point to the position (Xs, Ys, Zs) of the tool tip point Tp on the workpiece coordinate system. Obtain the vector V shown in (6),
Vx = 0… (4)
Vy = H * cos (Am)… (5)
Vz = H * sin (Am)… (6)
The X, Y, and Z axes are moved by this vector V, and the workpiece as shown in equations (7) to (9) from the position (Xm, Ym, Zm) of the control point P on the machine coordinate system ΣM at that time. The tool tip position (Xs, Ys, Zs) at the start of machining on the workpiece coordinate system ΣW is obtained by subtracting the origin position (Xw, Yw, Zw) of the coordinate system ΣW.
Xs = Xm−Xw (7)
Ys = Ym−Yw (8)
Zs = Zm−Zw (9)
Thus, after determining the position (Xs, Ys, Zs) of the tool tip point Tp at the start of machining on the workpiece coordinate system ΣW, the subsequent program command is regarded as being commanded in the stored workpiece coordinate system ( In the program, such an instruction is given), and interpolation is performed based on the speed F commanded on the work coordinate system ΣW. That is, when the next block command is (Xe, Ye, Ze, Ae, Ce), the control point P (X, Y, Z, A, C axis to be moved at every interpolation period Δt as follows: Machine coordinate position) (Xc, Yc, Zc, Ac, Cc) is obtained.
[0016]
First, the interpolation point (Xi, Yi, Zi) on the workpiece coordinate system is interpolated based on the command speed F (first interpolation). The interpolation cycle is Δt and the previous interpolation point on the workpiece coordinate system ΣW is (Xj, Yj, Zj) ((Xs, Ys, Zs) = (Xj, Yj, Zj) as described above at the start of machining)
K1 = Δt * F (10)
(Length to be interpolated between Δt)
D = √ ((Xe−Xs)² + (Ye−Ys)² + (Ze−Zs)²... (11)
(Block length)
Then,
Xi = K1 * [(Xe−Xs) / D] + Xj (12)
Yi = K1 * [(Ye−Ys) / D] + Yj (13)
Zi = K1 * [(Ze−Zs) / D] + Zj (14)
For the A axis and C axis, interpolation is performed from the start position (As, Cs) to the command position (Ae, Ce) (second interpolation), and the interpolation point (Ai, Ci) is obtained. At this time, the position of the interpolation point (Ai, Ci) is the same as the movement from the tool tip point (Xs, Ys, Zs) at the start to the command end point position (Xe, Ye, Ze) on the X, Y, and Z axes. Proportional distribution.
That means
K2 = (√ ((Xi−Xs)² + (Yi−Ys)² + (Zi−Zs)²)] / [√ ((Xe−Xs)² + (Ye−Ys)² + (Ze−Zs)²)]… (15)
Then,
Ai = K2 * (Ae−As) + As… (16)
Ci = K2 * (Ce−Cs) + Cs… (17)
It becomes.
[0017]
For each interpolation process, correction is made by the amount of table rotation to convert the interpolation point (Xi, Yi, Zi) of the linear axis, and on the machine coordinate system ΣM by the following equations (18) to (20) X, Y, Z axis positions (Xa, Ya, Za) are obtained. In the equations (18) to (20), (Xr, Yr, Zr) is a rotation center position set as a separate parameter.
Xa = (Xw + Xi-Xr) * cos (-Ci + Cz)-(Yw + Yi-Yr) * sin (-Ci + Cz) + Xr ... (18)
Ya = (Xw + Xi−Xr) * sin (-Ci + Cz) + (Yw + Yi−Yr) * cos (-Ci + Cz) + Yr… (19)
Za = Zw + Zi… (20)
For each interpolation process, a tool length correction vector V (Vx, Vy, Vz) is calculated from the interpolated tool head rotation axis position (Ai) and the tool length correction amount H.
Vx = 0… (21)
Vy = H * cos (Ai)… (22)
Vz = H * sin (Ai)… (23)
For each interpolation process, the linear axis position (Xa, Ya, Za) on the machine coordinate system ΣM and the tool length correction vector V are added and corrected to obtain the position (Xc, Yc, Zc) of the control point P on the linear axis. ). Also, (Ai, Ci) is (Ac, Cc).
(Xc, Yc, Zc) = (Xa, Ya, Za) + (Vx, Vy, Vz)… (24)
As described above, the machine coordinate position (Xc, Yc, Zc, Ac, Cc) of the control point P is obtained.
[0018]
The difference between the linear axis control point position (Xc, Yc, Zc) and the linear axis control point position (Xo, Yo, Zo) in the previous interpolation processing is output to the servo as the linear axis movement amount. The difference between the interpolated rotation axis position (Ac, Cc) and the rotation axis position (Ao, Co) in the previous interpolation process is output to the servo as the movement amount of the rotation axis.
[0019]
The current control point position (Xc, Yc, Zc) is set to (Xo, Yo, Zo), and the current rotation axis interpolation position (Ac, Cc) is set to (Ao, Co) to prepare for the next interpolation.
If the next command is a tool tip control end command, the command obtained by the following equations (25) to (27) for the X, Y, and Z axes is a program command (Xp, Yp, Zp) Regardless, it corresponds to the following program command.
Xp = Xc−Xw (25)
Yp = Yc−Yw (26)
Zp = Zc−Zw (27)
As described above, accurate machining can be performed on the workpiece placed on the rotating table while interpolating with a simple NC program.
Here, for simplicity, the workpiece coordinate system ΣW is not considered for the A and C axes, but the calculation is performed with respect to the A and C axes in consideration of the workpiece coordinate system ΣW in the same manner as the X, Y, and Z axes. Is also possible.
[0020]
In the above description, the work coordinate system ΣW is stored at the time of starting the tool tip point control, a program is commanded on the stored work coordinate system ΣW, and the stored work coordinate system ΣW rotates with the table rotation. It is. In this system, since the workpiece coordinate system ΣW rotates with the table 1, if the shape to be machined is commanded as the path of the tool tip point Tp in the workpiece coordinate system ΣW, this path and the workpiece coordinate system The relationship with ΣW is fixed, but since the workpiece coordinate system ΣW rotates with the table 1, the shape machined for the workpiece 3 on the table 1 is the same as the shape commanded in the workpiece coordinate system ΣW. Become.
[0021]
However, it may be programmed on a fixed workpiece coordinate system. That is, the workpiece coordinate system ΣW does not rotate with the table rotation, and the program can be commanded on the workpiece coordinate system ΣW which is not affected by the table rotation.
[0022]
In this case, the position of the next block used in equations (10) to (15) is calculated by the following equations (28) to (30) instead of (Xe, Ye, Ze). (Xe1, Ye1, Ze1) is regarded as (Xe, Ye, Ze), and the processing after the equation (10) is performed. That is, as shown in FIG. 7, the position (Xe1, Ye, Ze) on the work coordinate system (work coordinate system rotating with the table) ΣW stored from the command position (Xe, Ye, Ze) on the non-rotated work coordinate system ΣWR Ye1, Ze1) is determined, and the position is regarded as a commanded position on the stored work coordinate system (work coordinate system rotating with the table) ΣW, and the processing from formula (10) is performed.
Xe1 = (Xw + Xe-Xr) * cos (Ce-Cz)-(Yw + Ye-Yr) * sin (Ce-Cz)-(Xw-Xr)… (28)
Ye1 = (Xw + Xe-Xr) * sin (Ce-Cz) + (Yw + Ye-Yr) * cos (Ce-Cz)-(Yw-Yr)… (29)
Ze1 = Ze (30)
Further, the tool direction may be specified by a direction vector such as I, J, K. A method of automatically calculating on the numerical controller (CNC) side what position the rotation axis should be interpolated based on the command by the direction vector may be adopted. In this case, the command for the next block is (Xe, Ye, Ze, Ae, Ce), but the command is (Xe, Ye, Ze, Ie, Je, Ke), and (Ie, Je, Ke) is A vector indicating the tool direction on the stored workpiece coordinate system is used. Then, the corresponding rotation axis position (Ae, Ce) is calculated from the direction vector (Ie, Je, Ke), and the above processing is performed using the calculated rotation axis position (Ae, Ce). Good.
[0023]
Further, the tool direction may be specified by a direction vector such as I, J, and K and a shift amount therefrom. When the tool tip point is a cutting point on the hemisphere at the tip of the ball end mill tool, the direction perpendicular to the workpiece surface is commanded by a direction vector of I, J, K as shown in FIG. 17, and the tool direction is set to I, J Therefore, it can be commanded with a shift angle Q in the tangential direction with respect to the program progression direction from the K direction. In that case, the command is (Xe, Ye, Ze, Ie, Je, Ke, Qe), (Ie, Je, Ke) is a vector indicating the vertical direction of the workpiece surface, and (Qe) is the programmed program progress The tangential shift angle with respect to the direction. Then, the corresponding rotation axis position (Ae, Ce) is calculated from (Ie, Je, Ke), (Qe) and the program progression direction, and the tool tip sphere is calculated from (Ie, Je, Ke) and the tool radius compensation amount D. Find the center. Then, the obtained tool tip sphere center may be used as the tool tip point in the above processing, and the above processing may be performed using the calculated rotational axis position (Ae, Ce).
[0024]
Here, regarding the shift angle Q, it is also possible to command the shift angle in the tangential direction with respect to the program progress direction as Q1, and the shift angle in the normal direction with respect to the program progress direction as Q2. In that case as well, the corresponding rotation axis position (Ae, Ce) is calculated, the tool tip sphere center is obtained from (Ie, Je, Ke) and the tool radius correction amount D, and the obtained tool tip sphere is obtained. The center may be the tool tip point in the above processing, and the above processing may be performed using the calculated rotation axis position (Ae, Ce).
[0025]
Further, when the tool tip point is a cutting point on the tip surface of the flat end mill tool, the tool direction is commanded by an I, J, K direction vector or a rotation axis position as shown in FIG. The distance between the point and the center of the tool tip is commanded with the tool radius compensation amount D. When the tool direction is commanded with I, J, K direction vectors, the command is (Xe, Ye, Ze, Ie, Je, Ke), and (Ie, Je, Ke) is a vector indicating the tool direction. Then, the corresponding rotation axis position (Ae, Ce) is calculated from (Ie, Je, Ke), and (Ie, Je, Ke) is calculated on the surface created by (Ie, Je, Ke) and the direction of travel of the program command. The position of the center of the tool tip surface is obtained as a point that is distanced from the tool tip by a tool radius correction amount D in the vertical direction. Then, the obtained tool tip surface center may be used as the tool tip point in the above processing, and the above processing may be performed using the calculated rotation axis position (Ae, Ce).
[0026]
FIG. 8 is a block diagram of a numerical controller (CNC) 100 according to an embodiment for carrying out tool tip point control according to the present invention. The CPU 11 is a processor that controls the numerical controller 100 as a whole. The CPU 11 reads out a system program stored in the ROM 12 via the bus 20 and controls the entire numerical control device according to the system program. The RAM 13 stores temporary calculation data, display data, and various data input by the operator via the display / MDI unit 70. The CMOS memory 14 is configured as a non-volatile memory that is backed up by a battery (not shown) and that retains the memory state even when the numerical controller 100 is turned off. In the CMOS memory 14, a machining program read via the interface 15, a machining program input via the display / MDI unit 70, and the like are stored. The ROM 12 is pre-stored with various system programs for executing processing in an edit mode and processing for automatic operation required for creating and editing a machining program.
[0027]
Various machining programs such as machining programs for executing the present invention can be input via the interface 15 or the CRT / MDI unit 70 and stored in the CMOS memory 14.
[0028]
The interface 15 enables connection between the numerical controller 100 and an external device 72 such as an adapter. A machining program, various parameters, and the like are read from the external device 72 side. Further, the machining program edited in the numerical control apparatus 100 can be stored in the external storage means via the external device 72. The PMC (programmable machine controller) 16 is a sequence program built in the numerical controller 100, and sends a signal to an auxiliary device of a machine tool (for example, an actuator such as a robot hand for tool change) via the I / O unit 17. Output and control. In addition, it receives signals from various switches on the operation panel provided on the machine tool body, performs necessary signal processing, and then passes them to the CPU 11.
[0029]
The display / MDI unit 70 is a manual data input device having a display, a keyboard, and the like. The interface 18 receives commands and data from the keyboard of the display / MDI unit 70 and passes them to the CPU 11. The interface 19 is connected to an operation panel 71 having a manual pulse generator and the like.
[0030]
The axis control circuits 30 to 34 for each axis receive the movement command amount for each axis from the CPU 11 and output the command for each axis to the servo amplifiers 40 to 44. In response to this command, the servo amplifiers 40 to 44 drive the servo motors 50 to 54 of the respective axes. The servo motors 50 to 54 for each axis have a built-in position / speed detector, and position / speed feedback signals from the position / speed detector are fed back to the axis control circuits 30 to 34 to perform position / speed feedback control. . In FIG. 8, the position / velocity feedback is omitted.
[0031]
The servo motors 50 to 54 drive the X, Y, Z, A, and C axes of the machine tool, and drive and control the 5-axis machine tool shown in FIGS. The spindle control circuit 60 receives a spindle rotation command and outputs a spindle speed signal to the spindle amplifier 61. The spindle amplifier 61 receives the spindle speed signal and rotates the spindle motor 62 at the commanded rotational speed. The position coder 63 feeds back a feedback pulse to the spindle control circuit 60 in synchronization with the rotation of the spindle motor 62 to perform speed control.
[0032]
The configuration of the numerical control device 100 as described above is not different from the configuration of the conventional numerical control device, and the numerical control device 100 drives and controls a 5-axis processing machine as shown in FIGS. Perform tip point control.
Therefore, an example of machining by tool tip point control by controlling a 5-axis machining machine of the type shown in FIG.
[0033]
<When work coordinate system ΣW rotates with table>
First, as shown in FIG. 6, the origin position (Xw, Yw, Zw) of the workpiece coordinate system ΣW in the machine coordinate system ΣM is set and the workpiece coordinate system ΣW is set and stored. Further, the rotational center position (Xr, Yr, Zr) of the table 1 (work 3) in the machine coordinate system ΣM is set and stored as a parameter. In the example described below, Xw = Xr and Yw = Yr are used, but they are not necessarily equal.
[0034]
Then, a machining program command in the tool tip point control mode of machining for the rotating workpiece 3 is created in the set workpiece coordinate system ΣW. The workpiece coordinate system ΣW is stored at the start of the tool tip point control. During the tool tip point control, the workpiece coordinate system ΣW rotates with the table, that is, the workpiece coordinate system ΣW is attached to the table 1. It will be.
[0035]
Therefore, as shown in FIG. 9, it is assumed that the following machining program command is issued to machine the straight line L on the rotating workpiece 3.
<Example of Program of the Present Invention 1—Work Coordinate System ΣW Rotates with Table>
N100 G54 H01 C30.0;: Work coordinate system selection, tool length compensation number designation
N101 G90 G00 X0.0 Y150.0 Z86.603 A 60.0 C 30.0; Positioning to the start point
N200 G43.4;: Tool tip point control start
N301 G01 X-86.603 Y-50.0 Z0.0 A 30.0 C 150.0 F5000; Cutting command for straight line L
N400 G49;: Tool tip point control end
In block N100, the numerical controller 100 stores and sets the workpiece coordinate system (G54 workpiece coordinate system origin position: Xw, Yw, Zw) at that time, and stores the tool length compensation amount H corresponding to the tool compensation number 01. To do. Here, the tool length correction amount H is 100.0, and the workpiece coordinate system ΣW and the rotation center position (Xw, Yw, Zw) = (Xr, Yr, Zr) = (200.0, 200.0, 100.0).
[0036]
In block N101, “G90” is an absolute command code, “G00” is a positioning command code, and the position of the control point P on the workpiece coordinate system ΣW is “X0.0 Y150.0 Z86.603 A 60.0. C 30.0 ".
[0037]
The command on the workpiece coordinate system ΣW is converted to the machine coordinate system ΣM, and the machine coordinate position (Xm, Ym, Zm, Am, Cm) is as follows.
Xm = 0.0 + 200.0 = 200.0… (31)
Ym = 150.0 + 200.0 = 350.0… (32)
Zm = 86.603 + 100.0 = 186.603… (33)
Am = 60.0… (34)
Cm = 30.0… (35)
Then, each axis of the machine tool is moved to the above position by the command of the block of N101. This state is shown in FIG.
[0038]
The command “G43.4” in the block N200 is a tool tip point control start command, and thereafter, the movement locus of the tool tip point Tp is commanded as a program until the end of the tool tip point control. The tool tip point Tp = (Xs, Ys, Zs) at the start is obtained from the current control point P, the tool direction (Am, Cm), and the tool length correction amount H by the command of “G43.4” of N200. If the current control point P (machine position) is (Xm, Ym, Zm) = (200.0, 350.0, 186.603), the tool direction is (A60.0, C30.0), and the tool length compensation amount H is 100.0, then From the formulas (1) to (3), the tool tip position Tp = (Xs, Ys, Zs) is (X0.0,
Y100.0, Z0.0).
Xs = Xm−Xw = 200.0−200.0 = 0.0 (36)
Ys = Ym−H * cos (Am) −Yw = 350.0−100.0 * cos (60.0) −200.0 = 100.0… (37)
Zs = Zm−H * sin (Am) −Zw = 186.603−100.0 * sin (60.0) −100.0 = 0.0… (38)
The above value is also set to (Xj, Yj, Zj), and the machine coordinate position (Xm, Ym, Zm, Am, Cm) of the control point P is set to (Xo, Yo, Zo, Ao, Co). Also, the C axis position 30.0 is Cz.
[0039]
The state at this time is the state of FIG. 10A, and the tool 2 is positioned at the machining start position of the straight line L.
“G01” in the block of N301 is a cutting feed command, the tool tip point Tp = (Xs, Ys, Zs) is (X-86.603, Y-50.0, Z0.0), and the tool direction is (A30.0, C150). .0) is a command for cutting at a feed rate F of 5000 mm / min up to the target value.
[0040]
For the X, Y, and Z axes, from the tool tip point Tp (Xs, Ys, Zs) at the start to (X0.0, Y100.0, Z0.0), the command position (Xe, Ye, Ze) = (X- 86.603, Y-50.0, Z0.0) is interpolated to obtain the interpolation point (Xi, Yi, Zi). That is, the interpolation points (Xi, Yi, Zi) are obtained by performing calculations of equations (10) to (14). If the interpolation cycle Δt = 1msec,
K1 = 1msec * 5000mm / min = 0.083mm… (39)
D = √ ((-86.603−0.0)² + (-50.0−100.0)² + (0.0−0.0)²) = 173.205… (40)
Xi = 0.083 * (86.603 / 173.205) + Xj = 0.042 + Xj… (41)
Yi = 0.083 * (150.0 / 173.205) + Yj = 0.072 + Xj… (42)
Zi = 0.0… (43)
For the A axis and C axis, interpolation is performed from the current position (A60.0, C30.0) to the command position (A 30.0, C150.0) to obtain the interpolation point (Ai, Ci). At this time, the position of the interpolation point (Ai, Ci) is changed from the position (Xs, Ys, Zs) at the start of machining of the tool tip point Tp to the command end point position (X0.0, Y100.0, Z0.0). Xe, Ye, Ze) (X-86.603, Y-50.0 Z0.0) and the same proportional distribution. That is, from equation (15),
K2 = (√ ((Xi−0.0)² + (Yi−100.0)² + (Zi−0.0)²)] / [√ ((-86.603−0.0)² + (-50.0−100.0)² + (0.0−0.0)²)]… (44)
Then, from equations (16) and (17)
Ai = K2 * (30.0−60.0)… (45)
Ci = K2 * (150.0−30.0)… (46)
It becomes.
[0041]
For example, when the interpolation points (Xi, Yi, Zi) of the X, Y, and Z axes are (−43.302, 25.0, 0.0), Ai = 45.0, Ci = 90.0 (see FIG. 10B).
[0042]
Interpolation position (Xa, Ya. Za) on the machine coordinate system ΣM where the tool tip point Tp actually moves from the interpolation point (Xi, Yi, Zi) of the X, Y, Z axis and the interpolation position (Ci) of the C axis Is calculated by calculating the equations (18) to (20). For example, as shown in FIG. 10B, when the interpolation position of the C axis is Ci = 90.0, the position of the interpolation point of the X, Y, Z axis is (Xi, Yi, Zi) = (− 43.302, 25.0, 0.0), and by performing the equations (18) to (20) as shown below, the interpolation position (Xa, Ya. Za) of the tool tip point Tp on the machine coordinate system ΣM = (175.0, 243.302, 100.0) is obtained.
Xa = (-43.302) * cos (-90.0 + 30.0) -25.0 * sin (-90.0 + 30.0) + 200.0 = 200.0 ... (47)
Ya = (-43.302) * sin (-90.0 + 30.0) + 25.0 * cos (-90.0 + 30.0) + 200.0 = 250.0… (48)
Za = 0.0 + 100.0 = 100.0… (49)
Further, a tool length correction vector V is obtained from the interpolation position (Ai) of the A axis.
When Ai = 45.0, the tool length correction vector V is (0.0, 70.711, 70.711) from the equations (21) to (22).
Vx = 0.0… (50)
Vy = 100 * cos (45.0) = 70.711… (51)
Vz = 100 * sin (45.0) = 70.711… (52)
Therefore, the calculation of Expression (24) is performed to add the tool length correction vector V to the interpolation position (Xa, Ya. Za) of the tool tip point Tp on the obtained machine coordinate system ΣM, and the machine coordinate system ΣM is obtained. The position (Xc, Yc, Zc) of the control point P is obtained.
Xc = 200.0 + 0.0 = 200.0 (53)
Yc = 250.0 + 70.711 = 320.711… (54)
Zc = 100.0 + 70.711 = 170.711… (55)
The difference between the control point Tp (Xc, Yc, Zc) of the X, Y, Z axis in the previous interpolation cycle and the previous control point Tp (Xo, Yo, Zo) is calculated as the X, Y, Z axis in the current interpolation cycle. Is output to the axis control circuits 30 to 32 for the X, Y, and Z axes. At the same time, the difference between the interpolation position (Ao, Co) of the A and C axes in the previous interpolation cycle and the interpolation point (Ai, Ci) = (Ac, Cc) of the A and C axes in the current interpolation cycle is The movement amounts of the A and C axes in the interpolation cycle are output to the A axis and C axis control circuits 33 and 34. Further, the current position (Xc, Yc, Zc) of the control point P is (Xo, Yo, Zo), and the tool direction (Ac, Cc) is (Ao, Co).
[0043]
As described above, the workpiece 3 is moved to the position commanded by the block N301 while being driven to the X, Y, Z, A, and C axis interpolation positions by performing the interpolation process, and the workpiece 3 is cut. FIG. 10C shows a state in which the processing has been completed after reaching the processing end position.
[0044]
“G49” in the block of N400 is a code for the end of tool tip point control. When this code is read, the last interpolation point (Xc, Yc, Zc) for the control point P is expressed by the equations (25)-( 27) is converted into a work coordinate system, and is regarded as a program command (Xp, Yp, Zp), and corresponds to the subsequent program command.
Xp = Xc−Xw = 200.0−200.0 = 0.0… (56)
Yp = Yc−Yw = 386.603−200.0 = 186.603… (57)
Zp = Zc−Zw = 150.0−100.0 = 50.0… (58)
Thereby, the cutting of the straight line L is completed as shown in FIG. In the conventional cutting of the straight line L described with reference to FIGS. 3 to 5, in the above-described <conventional program example>, it has been described that the straight line L is cut in two blocks “N301” and “N302”. Since these two blocks cannot perform high-precision straight line processing, more blocks are actually required. However, as described above, the present invention may be an instruction of one block “N301” as shown in <Example 1 of the program of the present invention> and FIGS.
[0045]
In the above-described example, the tool direction is indicated by the position of the A axis indicating the rotation angle of the tool 2 and the position of the C axis indicating the rotation of the table. However, the tool direction is expressed as I, J, K. It is also possible to specify a specific direction vector and automatically calculate at which position the rotation axis should be interpolated on the numerical controller side.
[0046]
In this case, in the above program, N301 commands A30.0 C150.0, which is the direction of X: -0.866, Y: -0.5, Z: 0.577 on the stored work coordinate system. It is. Therefore, I-0.866 J-0.5 K0.577 is commanded instead of A30.0 C150.0, and the actual movement direction of the A-axis and C-axis from this I, J, K direction is A30.0.
It may be calculated by the numerical control device that it is C150.0.
[0047]
<When workpiece coordinate system ΣW is fixed>
Next, an embodiment in which programming is performed on a fixed work coordinate system ΣWR without rotating with the table will be described. That is, an embodiment will be described in which the workpiece coordinate system ΣWR does not rotate with the table rotation, and the program is commanded on the workpiece coordinate system ΣWR which is not affected by the table rotation.
[0048]
The program command for machining the straight line L is as follows, as in <Program example 1 of the present invention> described above.
<Program Example 2 of the Present Invention-Fixing Work Coordinate System ΣW>
N100 G54 H01 C30.0;: Work coordinate system selection setting, tool length compensation number designation
N101 G90 G00 X0.0 Y150.0 Z86.603 A 60.0 C 30.0;
: Positioning to the start point
N200 G43.4;: Tool tip point control start
N301 G01 X0.0 Y100.0 Z0.0 A 30.0 C 150.0 F5000;
: Straight line L cutting command
N400 G49;: Tool tip point control end
This “program example 2” is different from “program example 1” in the “N301” block.
"G01 X-86.603 Y-50.0 Z0.0 A 30.0 C 150.0 F5000"
However, in “Program Example 2”,
“G01 X0.0 Y100.0 Z0.0 A 30.0 C 150.0 F5000”
Only the command of this block is different and the others are the same.
[0049]
Since the command of the block “N301” in this “program example 2” is commanded at the tool tip position Tp on the fixed work coordinate system ΣWR, the work coordinates that rotate this position with the rotation of the table 1 If converted to a position on the system, the processing thereafter is the same as the processing in the first program example.
[0050]
That is, the workpiece coordinate system that rotates together with the table 1 by performing the following calculation represented by the equations (28) to (30) with respect to the position commanded in this block (the processing end target position) (Xe, Ye, Ze). The upper position (Xe1, Ye1, Ze1) is obtained, and the position (Xe1, Ye1, Ze1) is regarded as a command position on the workpiece coordinate system ΣWR that rotates with the table 1, and in the subsequent processing, (Xe1, Ye1, Ze1) may be used instead of (Xe, Ye, Ze).
Xe1 = (Xw + Xe-Xr) * cos (Ce-Cz)-(Yw + Ye-Yr) * sin (Ce-Cz)-(Xw-Xr)
= 0.0 * cos (120.0) −100.0 * sin (120.0)
= -86.603… (59)
Ye1 = (Xw + Xe−Xr) * sin (Ce-Cz) + (Yw + Ye−Yr) * cos (Ce-Cz) − (Yw−Yr)
= 0.0 * sin (120.0) + 100.0 * cos (120.0)
= -50.0… (60)
Ze1 = Ze = 0.0… (61)
As described above, the converted position (Xe1, Ye1, Ze1) = (− 86.603, -50.0, 0.0) is the command “X-86.603 Y-50.0 Z0.0” of the block “N301” of “Program Example 1”. The subsequent processing operations are the same as those described in the first program example.
[0051]
FIG. 11 is a flowchart of tool tip point control executed by the processor 11 of the numerical controller 100.
[0052]
When the processor 11 reads “G43.4” of the tool tip point control command from the program, the processor 11 starts the processing shown in FIG. As shown in the previous program examples 1 and 2, before the tool tip point control command “G43.4” is read, the workpiece coordinate system ΣW (Xw, Yw, Zw), tool length correction amount H Is specified and stored. Further, it is assumed that the tool has already been positioned at the machining start position by the tool tip point control.
[0053]
When the tool tip point control command “G43.4” is read, the position (Xm, Ym, Zm) of the current control point P being positioned, the rotation angles Am, Cm of the A axis and C axis, and the tool length By calculating the equations (1) to (3) from the correction amount H, the tool tip point position (Xs, Ys, Zs) at the start of machining on the workpiece coordinate system ΣW is obtained (step S1).
[0054]
The position (Xm, Ym, Zm, Am, Cm) is stored as the position (Xo, Yo, Zo, Ao, Co) at the time of the previous interpolation, and one tool tip position (Xs, Ys, Zs) is stored. Stored as the previous interpolation position (Xj, Yj, Zj). Further, (Am, Cm) is stored as (As, Cs), and Cm is stored as Cs (step S2).
Thereafter, the next block is read to determine whether or not the tool tip point control end command (G49) is reached (steps S3 and S4). Since the cutting command is programmed after the tool tip point control command (G43.4), this command is read, and the process proceeds to step S5, where the command position (Xe, Ye, Ze) and step read in this block are read. Based on the current tool tip position (Xs, Ys, Zs) obtained in S1 and the command speed F, the expressions (10) and (11) are calculated, the length K1 to be moved during the interpolation cycle, and the block The machining length D commanded in step S5 is obtained (step S5).
[0055]
Using the obtained K1, D, command position (Xe, Ye, Ze), current position (Xs, Ys, Zs), position (Xj, Yj, Zj), equations (12) to (14) The calculation is performed to obtain the interpolation point position (Xi, Yi, Zi) (step S6). Further, the proportional constant K2 is obtained by performing the calculation of the expression (15) (step S7), and the calculations of the expressions (16) and (17) are performed by using the obtained proportional constant K2, and the interpolation of the A and C axes is performed. Points Ai and Ci are obtained (step S8).
[0056]
Based on the calculated rotation angle Ci of the table 1, the calculation of the equations (18) to (20) is performed, and the interpolation point position (Xi, Yi, Zi) is rotated by this rotation amount, and the tool tip position on the machine coordinate system (Xa, Ya, Za) is obtained (step S9).
Further, from the rotation angle Ai of the A axis that is the obtained tool inclination, the calculations of equations (21) to (23) are performed to obtain the tool length correction vector V (Vx, Vy, Vz) (step S10). The tool length correction vector V (Vx, Vy, Vz) is added to the tool tip point position (Xa, Ya, Za) on the coordinate system (formula (24)), and the position of the control point P on the machine coordinate system ( Xc, Yc, Zc) is obtained (step S11).
[0057]
(Xi, Yi, Zi) is stored as (Xj, Yj, Zj), and (Ai, Ci) is stored as (Ac, Cc) (step S12) to prepare for the next interpolation process. Then, the current position (Xo, Yo, Zo) is subtracted from the position (Xc, Yc, Zc) of the control point P obtained by interpolation, and the value is obtained as the X, Y, Z axis servo motors 50, 51, 52. Is output as a command to. Further, the current positions Ao and Co are subtracted from the interpolation positions Ac and Cc of the A and C axes, and the values are output as commands to the servo motors 53 and 54 of the A and C axes (step S13).
[0058]
Next, the position (Xc, Yc, Zc) of the control point P and the interpolation positions Ac, Cc of the A and C axes are stored as the current position (Xo, Yo, Zo) and the current positions Ao, Co (step) In step S14, it is determined whether the end point position of the block has been reached (step S15). If not reached, the process returns to step S6, and the processes in and after step S6 are performed.
[0059]
Thereafter, the processing of step S6 to step S16 is repeatedly executed, and each axis is driven and controlled by interpolation to the command position. When it is determined in step S15 that the command position in this block has been reached, this end point position ( Xe, Ye, Ze, Ae, Ce) is stored as the start position of the next block (step S16), the process returns to step S3, and the processes after step S3 are executed. If the machining block continues and the tool tip point control end command is not read, the processing from step S3 is repeatedly executed. When the tool tip point control end code is read, the process proceeds from step S4 to step S17. (Xp, Yp, Zp) is obtained by calculating the equations (25) to (27), and this is used as a program command to end the tool tip point control process.
[0060]
As described above, when the position of the tool tip point control program is commanded in the fixed workpiece coordinate system ΣWR that does not rotate with the table, the command position (Xe, Ye read out in step S5). , Ze) is converted into a position (Xe1, Ye1, Ze1) on the coordinate system ΣW that rotates with the workpiece by the equations (28) to (30), and this position (Xe1, Ye1, Ze1) is converted into the command position (Xe, The processing shown in FIG. 11 may be executed instead of Ye, Ze).
[0061]
Further, when the method of correcting the tool correction vector V first is adopted, only the process of step S1 is different. In this case, the current position (Xm, Ym, Zm) of the control point P on the machine coordinate system of the X, Y, Z axes, the current position (Am, Cm) of the A, C axes are read, and the A, C axes are read. From the current position (Am, Cm) and the tool correction amount H, the calculation of equations (4) to (6) is performed to obtain the tool correction vector V, and the X, Y, and Z axes are moved by this vector. Then, the positions of the X, Y, and Z axes after the movement are read, and this is used as the current position (Xm, Ym, Zm) of the control point P, and the calculations of the equations (7) to (9) are performed. The tool tip point position (Xs, Ys, Zs) at the start of machining on ΣW may be obtained. The other processes are the same as those shown in FIG.
[0062]
  In the above-described embodiment, a machine tool having one axis (C) for rotating the table and one axis (A) for rotating the tool head has been described. It can be similarly applied to a machine tool having two axes. Further, as shown in FIG. 19, the present invention can be applied to a machine tool that has only the table rotation axis C and does not have the tool head rotation axis A. In this case, all the command values, current values, etc. for the A-axis should be “0” or a fixed value..
  Furthermore, the present invention can realize 5-axis machining on a lathe. For example, the figure20As shown, the present invention can also be applied to a lathe in which the workpiece 3 is rotated about the C axis and the tool 2 is rotated about the B axis.
  Figure20The 5-axis machining machine with a lathe shown in FIG. 1 fixes the workpiece 3 on the workpiece gripping base 4 with a jig, drives the tool 2 in the X, Y, and Z-axis directions by orthogonal linear movement axes, and uses the B-axis. Is configured to rotate around the Y axis. This figure20The lathe machine shown in Fig. 1 uses only the B axis for rotating the tool 2 in place of the A axis for rotating the tool head in the 5-axis machine shown in Fig. 1 described above. The present invention can be applied by using the B axis instead of the A axis.
[0063]
The tool tip point Tp is a position designated on the tool 2, and in the above description, the tool tip point Tp has been described as the apex of the tool. However, the tool tip point Tp is shown in FIGS. As shown in FIG. 4, various positions on the tool 2 are set as the tool tip point Tp.
[0064]
12 is a diagram showing a case where the tool tip point Tp is at the tool tip, FIG. 13 is a diagram where the tool tip point Tp is at the center of the hemisphere at the tip of the ball end mill tool, and FIG. 15 is a cutting point on the hemisphere at the tip of the end mill tool, FIG. 15 is a case where the tool tip point Tp is the center of the tip surface of the flat end mill tool, and FIG. It is a figure which shows the case where it is a point.
[0065]
【The invention's effect】
The present invention is a numerical control device for a machine tool having at least one axis for table rotation, and further having one axis for table rotation and one axis for tool head rotation, or two axes for table rotation. Yes, when performing machining in which the tool tip moves along the desired path at the desired speed while these rotary axes rotate, the program length can be shortened and the tool length is changed. There is no need to recreate a program from the CAM, and the machining cycle time can be shortened.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram of a 5-axis machine having one axis for rotating a table and one axis for rotating a tool head.
FIG. 2 is an explanatory diagram of a 5-axis processing machine in which a table is rotationally controlled by a rotation axis A around an X axis and a rotation axis C around a Z axis.
FIG. 3 is an explanatory diagram of a main part of a machine tool having one axis (C axis) for rotating the table and one axis (A axis) for rotating the head of the tool.
FIG. 4 is an explanatory diagram of a conventional example in the case of cutting a straight line on a workpiece on a table while rotating the table and changing the tilt angle of the tool.
FIG. 5 is an operation explanatory diagram of straight line processing according to a conventional example.
FIG. 6 is a diagram illustrating the principle when a machine tool having one axis (C) for rotating the table and one axis (A) for rotating the tool head is controlled by the numerical control device according to the embodiment of the present invention. It is.
FIG. 7 is a principle explanatory diagram of another processing method according to the embodiment;
FIG. 8 is a block diagram of one embodiment of the present invention.
FIG. 9 is an explanatory diagram of linear cutting according to the embodiment.
FIG. 10 is an operation explanatory view of straight line machining according to the same embodiment.
FIG. 11 is an operation flowchart of the embodiment.
FIG. 12 is a diagram showing a case where the tool tip is at the tool tip.
FIG. 13 is an explanatory diagram when the tool tip point is at the center of a hemisphere at the tip of the ball end mill tool.
FIG. 14 is an explanatory diagram when the tool tip point is a cutting point on a hemisphere at the tip of the ball end mill tool.
FIG. 15 is an explanatory diagram when the tool tip point is the center of the tip surface of the flat end mill tool.
FIG. 16 is an explanatory diagram when the tool tip point is a cutting point on the tip surface of the flat end mill tool.
FIG. 17 is an explanatory diagram when the shift amount is specified by a direction vector when the tool tip point is a cutting point on the tip surface of the ball end mill tool.
FIG. 18 is an explanatory diagram when the shift amount is specified by a direction vector when the tool tip point is a cutting point on the tip surface of the flat end mill tool.
FIG. 19 is a diagram showing an example of a machine tool that has only a table rotation axis to which the present invention is applicable and does not have a tool head rotation axis.
FIG. 20 shows the present invention.It is explanatory drawing of the 5-axis processing machine by the applied lathe.
[Explanation of symbols]
1 table
2 tools
3 Work
4 Work gripper
100 Numerical controller
P control point
CO rotation center
CS C axis reference position

Claims (12)

In a numerical controller for controlling a machine tool having at least one linear movement axis and at least one rotary movement axis of a table, and continuously machining a workpiece fixed on the table with a tool,
A movement command means for providing a movement path command for the linear movement axis, a relative movement speed command for the workpiece and the tool, and a movement command for the rotary movement axis for giving a tool direction as a direction of the tool with respect to the table;
Means for defining a coordinate system on the table;
First interpolation means for interpolating the movement path command of the linear movement axis based on the relative movement speed command in a coordinate system defined on the table to obtain interpolation position information of the movement path;
Second interpolation means for interpolating the movement command of the rotational movement axis based on the movement path command and the relative movement speed command to obtain interpolation position information of the rotational movement axis;
Means for correcting the interpolation position information from the first interpolation means based on the interpolation position information of the rotational movement axis;
A tool tip point designated on the tool is driven by driving a servo motor of each axis corresponding to the corrected interpolation position information of the moving path and the interpolation position information of the rotational movement axis. A numerical control device characterized by moving on a commanded movement route at a commanded speed. The numerical control device according to claim 1, wherein the machine tool further includes a rotational movement axis that inclines the tool relative to the table in addition to the rotational movement axis of the table . The numerical control device according to claim 1, wherein the machine tool is provided with a rotational movement axis that inclines the table relative to the tool in addition to the rotational movement axis of the table. The means for correcting the interpolation position information from the first interpolation means corrects by taking into account the set tool length correction amount, tool radius correction amount, or both. Numerical control unit. The numerical control device according to claim 1, wherein the tool direction is given as a movement command for a rotational movement position of a rotational movement shaft. The numerical control device according to claim 1, wherein the tool direction is given as a direction vector. The movement command means commands the movement path command of the linear movement axis based on the coordinate system on the assumption that the coordinate system defined on the table rotates together with the table. The numerical control device according to claim 1. The movement command means converts the movement path command of the linear movement axis, which is commanded based on a coordinate system that does not rotate with the table, into a coordinate system that rotates with the table, and converts the linear movement axis command. The numerical control apparatus according to claim 1, wherein a shaft movement path command is used. The numerical control apparatus according to claim 1, wherein the tool tip point is a vertex of the tool. The numerical control device according to any one of claims 1 to 8, wherein the tool tip point is a center of a hemisphere at a tip of a ball end mill tool or a cutting point on a hemisphere at a tip of a ball end mill tool. The numerical control device according to any one of claims 1 to 8, wherein the tool tip point is a center of a tip surface of the flat end mill tool or a cutting point of a tip surface of the flat end mill tool. In a numerical control device for controlling a machine tool having at least one linear movement axis and at least one rotation axis, and continuously machining a workpiece fixed on a workpiece gripping table rotated by the rotation axis with a tool,
A movement path command for the linear movement axis, a relative movement speed command for the workpiece and the tool, and a movement command for the rotation shaft for giving a tool direction as a direction of the tool with respect to a work gripper rotated by the rotation shaft Movement command means;
Means for defining a coordinate system on a work gripper that is rotated by the rotation axis;
First interpolation for obtaining interpolation position information of the movement path by interpolating the movement path command of the linear movement axis on the basis of the relative movement speed command in a coordinate system defined on a workpiece gripping table rotated by the rotation axis Means,
Second interpolation means for interpolating the movement command of the rotation axis based on the movement path command and the relative movement speed command to obtain interpolation position information of the rotation axis;
Means for correcting the interpolation position information from the first interpolation means based on the interpolation position information of the rotation axis;
A tool tip point designated on the tool is commanded by driving the motor of each corresponding axis based on the corrected interpolation position information of the moving path and the interpolation position information of the rotating shaft. A numerical control device characterized in that it moves at a commanded speed on a moving route.

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