JP3219115B2 - Block data processing method for numerical controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for distributing a moving amount of a program block of a numerical controller for controlling a machine tool to each axis.

[0002]

2. Description of the Related Art Conventionally, in a numerical control device for controlling a machine tool, each program block is distributed to each axis as a movement pulse at each distribution cycle. Here, the program block, the slide into dispensing movement pulse for each axis corresponding to the feed speed of each the distribution period for each distribution period, a pulse less than the feed speed of each end thereof dispensing cycle as excess pulse It may remain. If this surplus pulse is distributed to each axis as it is, the moving speed of each axis will decrease only for one distribution cycle that outputs the surplus pulse,
This can cause mechanical shock. As a method for solving this, to previously obtain a surplus pulse occurring in one block before the interpolation, open to the preceding methods is dispersed in distribution pulses distributes to in the block Hei 4-305707
It is shown. Using the method disclosed there ,
Even when an extra pulse is generated, the moving speed of each axis in each distribution cycle does not decrease for one distribution cycle. In addition, since the surplus pulses are obtained before interpolation, pulse distribution can be performed at high speed.

[0003]

However, in the actual machining program, the amount of movement per block is a block smaller than the amount of movement per distribution cycle corresponding to the feed speed of the block (hereinafter referred to as an extremely small block). There is.
For example, the distribution cycle is 1 msec, and the feed speed is 6 m / mi.
When n is set, the moving amount in one distribution cycle is 100 μm, but the moving amount per block is several μm in the machining program.
In some cases, a very small block having a size of m to several tens μm is included. When the NC data is created using the CAM, such a minimal block is generated by the NC during the processing of the CAM.
May be included in data. Therefore, in this case, FIG.
Since the moving amount of the minimum block such as N3 and N4 in the machining program shown in (1) is less than the moving amount in one distribution cycle, the blocks N3 and N4 become the surplus pulses as described above. In the prior art, the extra pulse was distributed and distributed and absorbed in the block where the extra pulse occurred. However, in the case of the above-mentioned minimal block, the block itself is an extra pulse, so the extra pulse in the block was used. Inability to absorb pulses. Therefore, in the related art, there is a problem that the feed speed is reduced in the very small block as shown in FIG. Therefore, an object of the present invention is to provide a pulse distribution method that does not cause a speed reduction even with such a very small block.

[0004] In order to solve the above problems, a first invention is to provide
In a block data processing method of a numerical control device having a function of processing a fraction generated by dividing a movement amount of one block of an NC program by a movement amount per distribution cycle,
Movement of one block in the C program, the case is a minimum block to be less than the amount of movement per distribution period corresponding to the feed speed of the distribution period <br/>, prior to processing of the fractional said The moving amount sequentially added until the added value of two or more blocks after the minimum block exceeds the moving amount per distribution cycle is replaced with the two or more blocks to be added, and a new block is formed. is there. The second invention is the block data processing method for a numerical control apparatus having a function of processing a fraction generated by dividing by the moving amount per distribution period the amount of movement of one block of the NC program in the NC program If the movement amount of one block is less than a predetermined value, the sum of two or more blocks after the minimum block exceeds the movement amount per distribution cycle prior to the processing of the fraction. The moving amount sequentially added up to the above is replaced with two or more blocks to be added, and a new block is obtained.

[0005]

According to the above method, even when the movement amount of one block in the program is smaller than the movement amount of one distribution cycle corresponding to the feed speed at that time, the movement amount of the block is one movement period. Until the amount exceeds the moving amount, the moving amount of the next block is sequentially added, so that blocks less than the moving amount of one distribution cycle are removed, and the moving speed of the block having the smaller moving amount is reduced without lowering the feed speed. It is possible to perform interpolation and distribute the movement pulse to each axis.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart of the present invention, and shows a loop process for performing acceleration / deceleration interpolation and pulse distribution while reading a movement command block from a memory or the like. First, one movement command block is read. Next, when the very small block was stored when the block was read last time, the movement amount of the very small block is added to the movement amount of the currently read block to obtain a current movement command block. Next, the movement distance of the current movement command block is calculated. For example, the movement amounts of the X, Y, and Z axes are x, y,
In the case of z, the moving distance L is given by the following equation. L = (x ² + y ² + z ² ) ^1/2 (1) Next, the moving distance L is compared with a threshold value. The threshold value at this time may be a movement amount per distribution cycle corresponding to the feed speed at that time, or may be a preset value. If the moving distance L is equal to or greater than the threshold value, the minimum block area is cleared to 0 (zero), acceleration / deceleration interpolation and pulse distribution are performed, and the process returns to the next block reading process. Conversely, if the moving distance L is less than the threshold value, the current movement command block is stored in the minimal block area and the next block is read. The saved tiny block is added to the next read block. The above processing is repeated together with the acceleration / deceleration interpolation of the movement command block and the pulse distribution processing. For example, in a machining program as shown in FIG. 5, if the movement amount per one distribution cycle is 100 μm, the blocks N3 and N4 are extremely small blocks. Such a very small block is not always created faithfully to the actual micro-machined shape, and may be output as a fraction in the CAM calculation process. Therefore, there is a case where it is not necessary to move faithfully in response to such a movement command of the very small block. In such a case, in the present invention, the moving amount of the minimal block is added to the moving amount of the next block. If the movement amount of the next block obtained in this way has not yet exceeded the movement amount of one distribution cycle, the movement amount is added to the movement amount of the next block. Thus, when the movement amount of the block exceeds the movement amount of one distribution cycle, the interpolation of the block is performed as usual, and the movement pulse is distributed to each axis. In other words, when the program shown in FIG. 5 is given to the NC device, the conventional method results in a processing shape as shown in FIG. 6 and a pulse distribution as shown in FIG. By applying the method of the present invention, FIG.
Is converted into the program shown in FIG. That is, the blocks N3 and N4 are absorbed by N5 and are treated as a new block N3. As a result, the processing shape is given as shown in FIG.
By the conventional surplus pulse distribution method, as shown in FIG. 4, the feed speed is also substantially constant, so that a decrease in the speed can be prevented. As described above, as a method of determining a threshold value for determining whether or not the block is a minimum block, in addition to a method of setting a movement amount in one distribution cycle corresponding to a feed speed at that time as a threshold value, an NC parameter or the like is used. A method of giving a fixed threshold value is conceivable.

[0007]

As described above, according to the present invention, the next movement command block is read and added until the movement distance of the movement command block becomes larger than the threshold value. Even when a very small block shorter than the moving amount per interpolation cycle corresponding to the feed speed at that time is read, the very small block is incorporated into the long block and distributed, so that only the very small block is distributed in one distribution cycle. This has the effect that the feed speed does not decrease. This is particularly effective when the movement command data created by the CAM is directly given as a movement command of the NC device.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 shows an example of a movement command block according to the present invention.

FIG. 3 is a command shape according to the present invention.

FIG. 4 is a command speed according to the present invention.

FIG. 5 shows an example of a movement command block according to the related art.

FIG. 6 shows a command shape according to the prior art.

FIG. 7: Command speed according to the prior art

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-205709 (JP, A) JP-A-2-146607 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05B 19/18-19/46

Claims (2)

(57) [Claims] 1. A block data processing method for a numerical control apparatus having a function of processing a fraction generated by dividing by the moving amount per distribution period the amount of movement of one block of the NC program, one block in the NC program The travel distance of
In that case a minimum block to be less than the amount of movement per distribution period corresponding to the feed speed of the distribution period, prior to processing of the fractional addition value is the distribution period of 2 or more blocks of the minimum block later A block data processing method for a numerical control device, characterized in that a moving amount sequentially added until a moving amount per hit is exceeded is replaced with the two or more blocks to be added and a new block is provided. 2. A block data processing method for a numerical control apparatus having a function of processing a fraction generated by dividing by the moving amount per distribution period the amount of movement of one block of the NC program, one block in the NC program The travel distance of
If the value is less than a preset value, prior to the processing of the fraction, the moving amount sequentially added until the added value of two or more blocks after the minimum block exceeds the moving amount per distribution cycle, A block data processing method for a numerical controller, wherein a new block is used instead of the two or more blocks to be added.