JPH1039913A - Nc data preparing method and nc device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an NC data preparing method and an NC device with which a servo motor can be controlled at desired feeding speed while utilizing linear acceleration/deceleration control characteristics after the interpolation of the NC device. SOLUTION: The table of relation between a remaining distance and the feeding speed expressing a desired feeding speed control curve is prepared. First of all, when a remaining distance x(j) is 0, feeding speed F(j) is found from this relation table and the combination data of the remaining distance x(j) and feeding speed F(j) are stored in a LIFO memory. Next, while using the last remaining distance x(j), feeding speed F(j) and time constant Ts, a remaining distance x(j+1) is newly calculated by the equality of x(j+1)=x(j)+F (j).Ts, the feeding speed is found from this relation table and the combination data of the both are stored in the LIFO memory. Then, after the calculation of the remaining distance and feeding speed and the storage of combination data into the LIFO data are repeated until the feeding speed found from the relation table gets coincident with the last speed, finally, the combination data of the remaining distance and feeding speed stored in the LIFO memory are successively read out backward and NC data are prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC data creating method and an NC apparatus for creating NC data for controlling a servomotor at a desired feed speed such as keeping a cutting load constant during machining of an NC machine tool. It is.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 1, for example, an NC device of an NC machine tool sequentially analyzes NC data and outputs position command information relating to the movement amount and feed speed of each axis. An analysis unit 1; an interpolator 2 that performs an interpolation operation on the position command information from the analysis unit 1 and outputs a servo command value;
The servo command value from the interpolator 2 is applied to each axis (X axis and Y axis in the figure).
And a plurality of servo circuits 4a and 4b for driving the servo motors 5a and 5b of each axis based on the servo command value of each axis from the distributor 3 respectively. In this NC device, for example,
As disclosed in JP-A-11764, an acceleration / deceleration control circuit is provided to prevent a shock due to a sudden change in speed caused by a step-like speed command of NC data from being transmitted to a machine. 5a and 5b are moved. There are two types of acceleration / deceleration control: an acceleration / deceleration method before interpolation and an acceleration / deceleration method after interpolation.

The acceleration / deceleration method before interpolation, as shown in FIG.
A pre-interpolation acceleration / deceleration control circuit 8 is provided between the data analysis unit 1 and the interpolator 2 so that the acceleration / deceleration control circuit 8 performs processing at regular intervals of interpolation along the tool path of NC data before performing interpolation / distribution processing. A speed error controlled by deceleration is calculated, and then interpolation points on a route separated by the product (distance) of the speed and the interpolation period are sequentially calculated. Therefore, a path error occurs due to acceleration / deceleration such as reduction in radius or corner droop. It is widely used for high-speed, high-precision machining. In this method, the data analysis unit 1 pre-reads the NC data and finds an end point speed at which a change in the tangential speed vector around the end point falls within an allowable value. Here, assuming that the allowable acceleration is A and the interpolation cycle is ΔT, the speed control by subsequently identifying the remaining distance is calculated by the following equation: F (i) = F (i−1) ± A × ΔT Therefore, the gradient is constant (α) as shown in FIG.
Is a straight line pattern. Note that even if the acceleration / deceleration of this method is performed, a slightly stepped step remains in the commanded speed of each axis after distribution, and the acceleration / deceleration method after interpolation which is usually less than that described below is also used in order to smooth the difference. See JP-A-6-282323).

On the other hand, in the post-interpolation acceleration / deceleration method, as shown in FIG. 3, post-interpolation acceleration / deceleration control circuits 9a and 9b are provided between the distributor 3 and the servo circuits 4a and 4b of each axis, respectively. After distributing the coordinate value of the interpolation point obtained by the NC data command speed to each axis, each axis performs acceleration / deceleration control for the axis speed command independently. Typical examples of this method include exponential acceleration / deceleration and linear acceleration / deceleration. As shown in FIG. 4, an exponential curve or linear (target) command speed is set at a preset time (acceleration / deceleration time constant). The pattern follows. FIG.
(A) and (b) are acceleration / deceleration control circuits 9 after X-axis interpolation, respectively.
FIG. 4 shows the speed patterns on the input side and output side of FIG.
(C) and (d) are acceleration / deceleration control circuits 9 after Y-axis interpolation, respectively.
3B shows a speed pattern on the input side and the output side of FIG. Also,
When performing such acceleration / deceleration control, it is necessary to perform tracking control by inputting a position command to the servo circuits 4a and 4b for each servo sampling cycle. 1- (a)
In the linear acceleration / deceleration, a position command controlled by acceleration / deceleration can be created by performing calculations according to Equation 1- (b).

[0005]

X0 (k) = x0 (k-1) + Δt · {xi (k) −x0 (k−1)} / Ts (a) x0 (k) = x0 (k−1) + Δt · ｛xi (k) −xi (k−N)｝ / Ts (b) where x0 is a position command subjected to acceleration / deceleration control as an input to the servo circuit, xi is a position command before acceleration / deceleration control, and N is Ts /
The constant Δt, Ts is the acceleration / deceleration time constant, and Δt is the servo sampling period.

[0006]

By the way, it has been conventionally known that, in an NC machine tool, if a servomotor is controlled at a feed rate at which a cutting load becomes constant, it is effective to improve tool life and machining accuracy. ing. Further, for example, in the case of a pocket corner where the tool trajectory changes at right angles from the X-axis direction to the Y-axis direction as shown in FIG. 5, the cutting depth in the radial direction of the tool as shown by the broken line in FIG. Since the distance increases toward the end point of 0, it is also known that the feed speed at which the cutting load is constant becomes a curve shown by a solid line in FIG.

However, the conventional acceleration / deceleration control described above involves:
Neither method takes into account the cutting process, such as cutting load fluctuations due to changes in the depth of cut, and it is not possible to execute feed speed control with a constant cutting load at the pocket corners.
This is one of the causes of a reduction in machining accuracy due to a reduction in tool life and a variation in the amount of elastic deformation of the tool.

Therefore, in order to solve such a problem,
When creating NC data by CAD / CAM or the like, attempts have been made to create the NC data by changing the command speed stepwise in accordance with a desired feed speed control curve such as keeping the cutting load constant. However, since the relationship with the acceleration / deceleration control of the NC device is not sufficiently considered, the speed command to the servomotor also includes a stepwise change, and the desired feed speed control cannot be realized. It is.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a linear acceleration / deceleration control after interpolation of an NC device, particularly when a product of a feed rate and a time constant is a moving distance. Focusing on the fact that the feed rate changes linearly for each time constant, the present invention provides an NC data creation method and an NC apparatus that can control a servo motor at a desired feed rate using this property. is there.

[0010]

In order to achieve the above object, the invention according to claim 1 is directed to a method for preparing NC data by CAD / CAM or the like without changing a conventional NC device. It is something to change. Specifically, a relation table between the remaining distance and the feed speed, which represents a desired feed speed control curve, is prepared in advance. Then, first, the feed rate F (j) when the remaining distance x (j) is 0 is obtained from the above relation table,
The combination data of the remaining distance x (j) and the feed speed F (j) is represented by L
Store in IFO memory. Next, using the previous remaining distance x (j), the feed speed F (j), and the time constant Ts, a new remaining distance x (j +
1) is calculated from the following equation: x (j + 1) = x (j) + F (j) · Ts, and the feed rate is obtained from the above relational table.
The combined data of the two is stored in the LIFO memory.
The calculation of the remaining distance and the feed speed and the storage of the combination data in the LIFO memory are repeated until the feed speed obtained from the relation table matches the previous one, and then the remaining distance finally stored in the LIFO memory is obtained. NC data is sequentially read in reverse from the combination data of the feed speed and the feed speed.

The NC data created by such a method is
When the servomotor is controlled by using the C device, the feed speed changes in a polygonal line for each acceleration / deceleration time constant Ts, and approximates a desired feed speed control curve in a relation table between the remaining distance and the feed speed. Therefore, the servo motor can be controlled at a desired feed speed. Here, the desired feed speed is not limited to making the cutting load constant, but also includes, for example, increasing the feed speed by a so-called S-shaped curve in order to reduce vibration at the start of starting or the like. Also,
The point where the remaining distance is 0 means not only the end point where the amount of movement in one axial direction becomes 0 as in a pocket corner, but also
When the desired feed speed is the above-mentioned S-shaped curve, it means the first point where the feed speed becomes maximum. In other words, it means a change end point when the feed speed changes.

According to a second aspect of the present invention, a conventional NC device is modified so that the NC device itself has a function of creating interpolation data using acceleration / deceleration control characteristics. More specifically, as an NC device that controls a servo motor at a desired feed speed based on NC data (including interpolation data), a relation table between a remaining distance and a feed speed representing a desired feed speed control curve is provided. Are prepared in advance and prepared, and interpolation data generating means having a LIFO memory is provided. Then, the interpolation data creating means sets the remaining distance x (j) to 0 when creating the interpolation data.
The feed speed F (j) at the time is obtained from the relation table created by the above-mentioned remaining distance / feed speed relation table creating means, and the combination data of the remaining distance x (j) and the feed speed F (j) is stored in the LIFO memory. Next, using the previous remaining distance x (j), the feed speed F (j), and the time constant Ts, the remaining distance x (j + 1) is newly calculated as follows: x (j + 1) = x (j ) + F (j) · Ts and the feed rate is obtained from the above relational table.
The combined data of the two is stored in the LIFO memory, and the calculation of the remaining distance and the feed speed and the storage of the combined data in the LIFO memory are repeated until the feed speed obtained from the relation table matches the previous one. Finally, it is provided to sequentially read in reverse from the combination data of the remaining distance and the feed speed stored in the LIFO memory and create interpolation data.

According to the NC device having such a configuration, the interpolation data is created by the interpolation data creation means. In the interpolation data, the feed speed changes in a polygonal line at every acceleration / deceleration time constant Ts, and the remaining distance is obtained. It is designed to approximate a desired feed speed control curve in the relationship table between the feed speed and the feed speed, so that if the servo motor is controlled based on the interpolation data, it is possible to control at a desired feed speed.

The invention according to claim 3 applies the invention according to claim 2 to feed speed control in which the cutting load is kept constant. That is, in the above-described remaining distance / feed speed relation table creating means, a tool path analyzing unit that analyzes data such as a pick amount and a corner angle other than the end point calculation, and shape data such as a tool radius and a tool object radius are stored in advance. And a relationship table between the remaining distance and the feed speed, which represents a feed speed control curve with a constant cutting load, based on the analysis data and the shape data.

As a result, the feed speed control with a constant cutting load is realized even at the pocket corners and the like, so that the tool life is improved and the reduction in machining accuracy due to the variation in the amount of elastic deformation of the tool is suppressed. Become. In addition, in the past, considering the corner portion where the cutting load is most applied to the tool, machining was performed with the feed speed kept low, but since the cutting speed constant feed speed control can command the best feed speed, Processing time can also be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7 shows an NC apparatus A of an NC machine tool which uses both the acceleration / deceleration control before interpolation and the acceleration / deceleration control after interpolation. The NC apparatus A sequentially analyzes the NC data 10 and outputs position command information relating to the movement amount and feed speed of each axis.
A data analysis unit 11, an acceleration / deceleration control circuit 12 for controlling acceleration / deceleration of the feed speed from the analysis unit 11, an acceleration / deceleration command value from the acceleration / deceleration control circuit 12, and acceleration / deceleration from the data analysis unit 11. An interpolator 13 that performs an interpolation operation based on the movement amount of each axis input by bypassing the deceleration control circuit 12 and outputs a servo command value, and outputs a servo command value from the interpolator 13 to each axis (X axis in the figure). And the distributor 1 for distributing the signals to the
4 is an acceleration / deceleration control circuit 1 for each axis for performing acceleration / deceleration control of the servo command value (specifically, for the speed command) of each axis from 4
5a, 15b, and servo circuits 16a, 16b of the respective axes for driving the servo motors 17a, 17b of the respective axes based on the servo command values subjected to the acceleration / deceleration control by the respective acceleration / deceleration control circuits 15a, 15b. I have. By the operation of the servo motors 17a, 17b of each axis, the feed mechanisms 18a, 1
8b performs a feeding operation.

The pre-interpolation acceleration / deceleration control circuit 12 is an embodiment of the present invention in addition to the original function of controlling the feed speed from the data analysis unit 11 while monitoring the remaining distance of the interpolator 13. As an embodiment, an interpolation data creation function for creating interpolation data independently of the NC data 10 is provided. That is, as shown in FIG. 8, the pre-interpolation acceleration / deceleration control circuit 12 includes a tool path analysis unit 21 for analyzing end point calculation and data such as a pick amount (cut allowance) and a corner angle. A shape data storage unit 22 in which shape data such as an object radius is stored in advance, and a remaining distance and feed representing a feed speed control curve with a constant cutting load based on the analysis data (including the end point calculation result) and the shape data. A remaining distance / feed speed relationship table creating unit 23 for creating a relationship table with speed;
(Last InFast Out) An interpolation data creation unit 25 as an interpolation data creation unit having a memory 24.

The above-mentioned remaining distance / feed speed relation table creating unit 23
In preparing a relation table between the remaining distance and the feed rate, which represents a feed rate control curve with a constant cutting load, first, the radial depth of cut t (xi) is obtained at an arbitrary remaining distance xi. For example, in the right angle corner (so-called pocket corner portion) shown in FIG. 9, when φ <0 °, t (xi) = t0 0 ° ≦ φ <90 ° t (xi) = t0 + R0 (1-COSφ When φ ≧ 90 °, t (xi) = R + {R ² − (R−t 0 + xi) ² }. Here, t0 is a removal allowance (radial depth of cut in a steady state), R0 is a workpiece radius, and R is a tool diameter. Also,

[0020]

[Number 2] ^{φ = COS -1 {(R0 2} + D0 2 -R 2) / (2 · D0
· R0)} + θ θ = also holds the relational expression ^{TAN -1 {(Y0-xi)} / Y0} Y0 = R0 + t0-R D0 = √ {Y0 2 + (Y0-xi) 2}.

Next, the cutting load is substantially equal to the cutting sectional area per unit time, that is, the cutting depth t (xi) at the remaining distance xi and the feed speed F (xi) as F (xi) .t (xi). Since it is proportional, a feed rate with a constant cutting load at the remaining distance xi can be obtained by Fi = F (xi) = F0.t0 / t (xi). Eventually, a delay due to the corrected linear acceleration / deceleration control (time constant = Ts) after machining is predicted, and the correction is performed by the following correction formula xi = xi−Fi · Ts / 2, and (xi, Fi) is corrected. A relation table between the remaining distance and the feed speed as shown in FIG. 10 is created by the combination. Therefore, the desired feed speed control curve (the cutting load in the present embodiment) according to the invention according to claim 2 is obtained by the remaining distance / feed speed relationship table creating unit 23, the tool path analyzing unit 21, and the shape data storage unit 22. A remaining distance / feed speed relation table creating means 26 is provided which prepares in advance a relation table between the remaining distance and the feed speed representing a constant feed speed control curve).

The interpolation data creating unit 25 creates interpolation data using the relation table between the remaining distance and the feed speed created by the remaining distance / feed speed relation table creating unit 23.
The creation of the interpolation data is performed according to the flowchart shown in FIG.

That is, in creating interpolation data,
At the given end point (point where the remaining distance is 0), it is necessary to output in accordance with the feed speed obtained from the relation table. First, the feed speed F (j) when the remaining distance x (j) is 0 is stored. It is obtained from the distance-feed speed relation table (steps S1 and S2), and the combination data (x (j), F (j), F (j)) of the remaining distance x (j) and the feed speed F (j).
(j)) is stored in the LIFO memory 24 (step S).
4).

Next, the previous remaining distance x (j) and the feed speed F
Using (j) and the time constant Ts, the remaining distance x (j + 1) is newly calculated from the following equation x (j + 1) = x (j) + F (j) · Ts, and the counter j is incremented. At the same time (step S5), the feed speed corresponding to the new remaining distance is obtained from the remaining distance / feed speed relationship table, and the combination data is similarly stored in the LIFO memory 24. here,
When the feed speed is obtained from the remaining distance / feed speed relationship table, as shown in FIG. 11, for the remaining distance x (j), x (i) ≦ x (j) ≦ x (i + 1) from the above relationship table. Section,
The feed speed F (j) when the remaining distance is x (j) is calculated by the following Expression 3.

[0025]

## EQU3 ## F (j) = F (i) + {F (i + 1) -F (i)}. Multidot.x (j)
−x (i)｝ / {x (i + 1) −x (i)} Then, the feed speed obtained by calculating the remaining distance and the feed speed and storing the combined data in the LIFO memory 24 from the relation table. Matches the previous one (F (j) =
F (j-1)) (step S3). After a while
The counter j is decremented (step S6). Finally, the remaining distance x (j) and F (j) are sequentially read in reverse from the combination data (x (j), F (j)) of the remaining distance and the feed speed stored in the LIFO memory 24. ), The position or the movement amount is obtained to create and output interpolation data (step S8). Then, when the counter j becomes 0 or less (j <0) (step S
7) That is, when the reading of all the combination data stored in the LIFO memory 24 is completed, the creation of the interpolation data is completed.

Thus, the acceleration / deceleration control circuit 12 before interpolation
The interpolation data created by the interpolation data creation section 25 is input to the post-interpolation acceleration / deceleration control circuits 15a and 15b of each axis via the interpolator 13 and the distributor 14.
After acceleration / deceleration control is performed at a and 15b, the signals are sent to the servo circuits 16a and 16b as servo command values. At this time, in the interpolation data, the feed speed F (j) is obtained from the relationship table between the remaining distance and the feed speed, which represents the feed speed control curve with a constant cutting load, for each time constant Ts of the post-interpolation acceleration / deceleration control. Therefore, the servo motors 17a and 17b of the respective axes are adjusted and controlled in a polygonal line shape approximating a feed speed control curve with a constant cutting load (see FIG. 6), for example, as shown in FIG. become. As a result, the tool life can be improved, and a decrease in machining accuracy due to a change in the amount of elastic deformation of the tool can be suppressed. Also, in the past, considering the corner part where the cutting load is applied most to the tool, machining was performed with the feed speed kept low, but since the cutting speed constant feed speed control can command the best feed speed,
Processing time can also be reduced.

FIG. 14 shows a speed pattern when the cutting load constant control (solid line) of the embodiment of the present invention and the high-speed high-precision control (broken line) of the conventional example are performed in the pocket corner portion.
Reference numeral 5 indicates a shape error. In FIG. 14, the reference point change pattern of the cutting load constant control of the present invention is plotted by using a two-dot chain line for a change pattern of the cutting depth in the radial direction of the tool and a one-dot chain line for a constant cutting volume as a reference. These are indicated by dotted solid lines. As can be seen from FIG.
The speed pattern of the example of the present invention is much closer to the constant cutting volume speed pattern than that of the conventional example, and an ideal speed pattern can be obtained. Further, as can be seen from FIG. 15, in the example of the present invention, the shape error at the corner portion is reduced to about half as compared with the conventional example.

It should be noted that the present invention is not limited to the above embodiment, but includes various other embodiments. For example, in the above embodiment, the NC device using both the pre-interpolation acceleration / deceleration control and the post-interpolation acceleration / deceleration control has been described.
The present invention can be similarly applied to the NC device of the post-interpolation acceleration / deceleration system shown in FIG.

Also, the NC data creation method of the present invention
Without changing the C device itself, N
This can be applied to the case where the C data 10 is created.
That is, in the process of preparing the NC data 10, a relation table between the remaining distance and the feed speed, which represents a desired feed speed control curve such as keeping the cutting load constant, is prepared in advance, and FIG.
The NC data may be created according to the same flowchart as in the second embodiment. FIG. 16 shows an example of NC data created by this method for controlling the feed rate at a constant cutting load at a right-angled corner.

Further, the present invention is not limited to an NC machine tool having a two-axis servomotor as in the above embodiment, but is also applicable to an NC machine tool having a three-axis or more servomotor. It goes without saying that you can do it.

[0031]

As described above, according to the NC data generating method and the NC apparatus of the present invention, the feed speed changes in a polygonal line for each acceleration / deceleration time constant, and the desired value in the relation table between the remaining distance and the feed speed is obtained. Since it will approximate the feed rate control curve,
Desired feed speed control can be reliably realized, and has a practically excellent effect.

In particular, when the present invention is applied to the feed rate control with a constant cutting load as in the invention according to the third aspect, it is possible to improve the tool life and suppress a decrease in machining accuracy due to a change in the amount of elastic deformation of the tool. At the same time, it is possible to shorten the machining time by instructing the best feed speed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an NC apparatus of an acceleration / deceleration system before interpolation.

FIG. 2 is a speed pattern diagram of acceleration / deceleration control before interpolation.

FIG. 3 is a block diagram of an NC apparatus of an acceleration / deceleration system after interpolation.

FIG. 4 is a speed pattern diagram of post-interpolation acceleration / deceleration control.

FIG. 5 is a schematic view showing a pocket corner portion.

FIG. 6 is a diagram showing a change in a cutting amount at a pocket corner portion and a constant cutting load feed speed.

FIG. 7 is a block diagram of an NC device that uses both an acceleration / deceleration method before interpolation and an acceleration / deceleration method after interpolation.

FIG. 8 is a block diagram of a portion of the acceleration / deceleration control circuit before interpolation that exhibits an interpolation data creation function.

FIG. 9 is a diagram for explaining a cutting amount at a right angle corner portion.

FIG. 10 is a diagram showing a relation table between a remaining distance and a feed speed.

FIG. 11 is a diagram for explaining a method of calculating a feed speed F (j) when the remaining distance is x (j).

FIG. 12 is a flowchart of creating interpolation data.

FIG. 13 is a diagram showing a change in the feed rate of the cutting load constant control of the present invention in a corner portion.

FIG. 14 is a diagram showing a speed pattern when the cutting load constant control of the example of the present invention and the high-speed and high-precision control of the conventional example are performed in the pocket corner portion.

FIG. 15 is a diagram showing a shape error.

FIG. 16 is a diagram showing an example of NC data created by the method of the present invention.

[Explanation of symbols]

 A NC unit 21 Tool path analysis unit 22 Shape data storage unit 23 Remaining distance / feed speed relationship table creation unit 24 LIFO memory 25 Interpolation data creation unit (interpolation data creation unit) 26 Remaining distance / feed speed relationship table creation unit

Claims (3)

[Claims] 1. An NC data creating method for creating NC data for controlling a servo motor at a desired feed speed, wherein a relationship table between a remaining distance and a feed speed representing a desired feed speed control curve is prepared in advance. First, the feed speed F (j) when the remaining distance x (j) is 0 is obtained from the above relation table, and the combination data of the remaining distance x (j) and the feed speed F (j) is stored in the LIFO memory. Next, the previous remaining distance x (j), feed speed F (j) and time constant T
Using s, the remaining distance x (j + 1) is newly calculated from the following equation x (j + 1) = x (j) + F (j) · Ts, and the feed rate is obtained from the above relation table.
The combined data of the two is stored in the LIFO memory, and the calculation of the remaining distance and the feed speed and the storage of the combined data in the LIFO memory are repeated until the feed speed obtained from the relation table matches the previous one. And NC data is sequentially read in reverse from the combination data of the remaining distance and the feed speed stored in the LIFO memory. 2. An NC device for controlling a servo motor at a desired feed speed based on NC data, wherein a relationship table between a remaining distance and a feed speed representing a desired feed speed control curve is prepared and prepared in advance. And an interpolation data creating means having a LIFO memory. The interpolation data creating means, when creating the interpolation data,
First, the feed speed F (j) when the remaining distance x (j) is 0 is obtained from the relationship table created by the above-described remaining distance / feed speed relationship table creating means.
The combination data of the remaining distance x (j) and the feed speed F (j) is represented by L
The remaining distance x (j + 1) is stored in the IFO memory, and then the remaining distance x (j + 1) is calculated using the previous remaining distance x (j), the feed speed F (j), and the time constant Ts.
Is calculated from the following equation x (j + 1) = x (j) + F (j) · Ts, and the feed rate is obtained from the above relational table.
The combined data of the two is stored in the LIFO memory, and the calculation of the remaining distance and the feed speed and the storage of the combined data in the LIFO memory are repeated until the feed speed obtained from the relation table matches the previous one. NC is provided so as to sequentially read in reverse order from the combination data of the remaining distance and the feed speed stored in the LIFO memory and finally create interpolation data.
apparatus. 3. The remaining distance / feed speed relation table creating means includes a tool path analysis unit for analyzing data such as a pick amount and a corner angle in addition to end point calculation, and a shape data such as a tool radius and a tool object radius in advance. A shape data storage unit that stores therein, and is provided so as to create a relation table between a remaining distance and a feed speed that expresses a feed speed control curve with a constant cutting load based on the analysis data and the shape data. The NC according to claim 2,
apparatus.