JPH0728519A - Block data processing method for numerical controller - Google Patents

Abstract

PURPOSE:To provide the pulse distributing method which is free from the reduction of speed regardless of a minimum block when a movement instruction (minimum block) where the extent of movement of one block does not reach the extent of movement per distribution period corresponding to the feed speed is included in NC data processed and outputted by CAD. CONSTITUTION:With respect to the block data processing method for numerical controller which has the function which divides the movement command value of one block of an NC program by the extent of movement per distribution period and processes generated fractions, the extent of movement, which is obtained by successively adding the extents of movement of the minimum block and two or more following blocks until the addition value exceeds the extent of movement per distribution period, is taken as the extent of movement of one new block instead of that of these two or more added blocks before the processing of fractions in the case of the minimum block whose extent of movement in the NC program does not reach the extent of movement per distribution period corresponding to the feed speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of distributing a movement 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 as a movement pulse to each axis at every distribution cycle. Here, if the movement pulse of each axis corresponding to the feed speed at that time is distributed from the program block for each distribution cycle, a pulse that does not reach the feed speed at that time may remain as a surplus pulse at the end. . If this surplus pulse is distributed to each axis as it is, the moving speed of each axis will decrease only during one distribution cycle in which the surplus pulse is output, which causes a shock to the mechanical device. As a method for solving this, Japanese Patent Laid-Open No. 4-305707 has introduced a method in which a surplus pulse generated in one block is obtained before interpolation and is distributed by being distributed to preceding distribution pulses in the block. By using this method, even if an extra pulse occurs, the moving speed of each axis in each distribution cycle does not decrease for one distribution cycle. Further, since the surplus pulse is obtained before interpolation, pulse distribution can be performed at high speed.

[0003]

However, in the actual machining program, when the amount of movement per block is smaller than the amount of movement per distribution cycle corresponding to the feed speed of the block (hereinafter referred to as a "minimum block"). There is.
For example, the distribution cycle is 1 msec and the feed rate is 6 m / mi.
When n is set, the movement amount for one distribution cycle is 100 μm, but the movement amount per block is several μ in the machining program.
There is a case where a minimum block having a size of m to several tens of μm is included. When the NC data is created using the CAM, such a minimal block is NC in the process of processing the CAM.
May be included in the data. Therefore, in this case, FIG.
Since the movement amount of the minimum blocks such as N3 and N4 in the machining program shown in (1) is less than the movement amount of one distribution cycle, the blocks N3 and N4 become the above-mentioned surplus pulses. In the conventional technique, the surplus pulse is dispersed and distributed and absorbed in the block in which the surplus pulse is generated, but in the case of the above-mentioned minimum block, since the block itself is the surplus pulse, the surplus pulse is The pulse cannot be absorbed. Therefore, in the conventional technique, there is a problem that the feed rate is reduced in the extremely 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 decrease even if such a minimal block is present.

[0004]

In order to solve the above problems, a first invention is a function of processing a fraction generated by dividing a movement command value for one block of an NC program by a movement distance per distribution cycle. In the block data processing method of the numerical controller having the above, when the moving amount of one block in the NC program is a minimum block less than the moving amount per distribution cycle corresponding to the feed speed at that time, the processing of the fraction is performed. Prior to the above, the movement amount sequentially added until the added value of two or more blocks after the minimum block exceeds the movement amount per distribution cycle is replaced with the two or more blocks to be added, and a new one is added. One block is used. A second invention is a block data processing method for a numerical control device having a function of processing a fraction generated by dividing a movement command value for one block of the NC program by a movement distance per distribution cycle. When the movement amount of one block is less than a preset value, the addition value 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 that is sequentially added until the above is replaced with the two or more blocks to be added, and a new one block is created.

[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 moves of one distribution cycle. Until the amount is exceeded, the movement amount of the next block is sequentially added. Therefore, blocks having a movement amount of one distribution cycle or less are removed, and the feed speed is not reduced in the block having a small movement amount described above. It is possible to perform interpolation and distribute the moving pulse to each axis.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart of the present invention, showing 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 move command block is read. Next, when the minimum block was saved when the block was read last time, the movement amount of the minimum block is added to the movement amount of the block read this time to obtain the current movement command block. Next, the moving distance of the current movement command block is calculated. For example, the movement amounts of the X, Y, and Z axes are x, y, and
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 and the threshold value are compared. 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. When the moving distance L is equal to or more 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 reading process of the next block. On the contrary, when the movement distance L is less than the threshold value, the current movement command block is saved in the minimum block area and the next block is read. The saved minimal block is added to the next loaded 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 the machining program as shown in FIG. 5, if the amount of movement per distribution cycle is 100 μm, the blocks N3 and N4 will be minimum blocks. Such an extremely small block is not created faithfully to the actual microfabrication shape, and may be output as a fraction in the CAM calculation process. Therefore, it may not be necessary to move faithfully to such a movement command of the minimum block. In such a case, the present invention adds the movement amount of the minimum block to the movement amount of the next block. If the movement amount of the next block thus obtained does not exceed the movement amount of one distribution cycle, the movement amount is added to the movement amount of the next block. Thus, when the moving amount of the block exceeds the moving amount of one distribution cycle, the block is interpolated as usual and the moving pulse is distributed to each axis. That is, when the program shown in FIG. 5 is given to the NC device, in the conventional method, the machining shape as shown in FIG. 6 results in the pulse distribution as shown in FIG. And applying the method of the present invention, FIG.
The machining program shown in is converted into the program shown in FIG. That is, the blocks N3 and N4 are absorbed by N5 and treated as a new block N3. As a result, the processed shape is given as shown in Fig. 3, and during pulse distribution,
According to the conventional method of distributing excess pulses, as shown in FIG. 4, the feed rate becomes almost constant, so that it is possible to prevent the speed from decreasing. As a method of determining the threshold value for determining whether the block is a minimum block, as described above, in addition to the method of using the movement amount of one distribution cycle corresponding to the feed speed at that time as the threshold value, an NC parameter or the like A method of fixing the threshold value may be considered.

[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 minimum block shorter than the movement amount per interpolation cycle corresponding to the feed speed at that time is read, the minimum block is incorporated into the long block and distributed, so that only the minimum block is distributed in one distribution cycle. The effect is that the feed rate will not decrease. This is particularly effective when the movement command data created by the CAM is directly given as the movement instruction of the NC device.

[Brief description of drawings]

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

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

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

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

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

FIG. 6 Commanded shape according to conventional technology

FIG. 7: Command speed according to prior art

Claims (2)

[Claims] 1. A block data processing method for a numerical controller having a function of processing a fraction generated by dividing a movement command value for one block of an NC program by a movement distance per distribution cycle, wherein 1 in the NC program is used. If the movement amount of the block is a minimum block that is less than the movement amount per distribution cycle corresponding to the feed speed at that time, prior to the processing of the fraction,
A moving amount that is 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 to form a new block. And a block data processing method for a numerical control device. 2. A block data processing method for a numerical controller having a function of processing a fraction generated by dividing a movement command value for one block of an NC program by a movement distance per distribution cycle, wherein 1 in the NC program is included. When the movement amount of the block is less than a preset value, the processing is sequentially performed until the added value of two or more blocks after the minimum block exceeds the movement amount per distribution cycle prior to the processing of the fraction. A block data processing method for a numerical controller, wherein the added movement amount is replaced with the two or more blocks to be added to form a new block.