JPH06138935A - Speed control method/device for numerically controlled machine tool - Google Patents

Abstract

PURPOSE:To improve the machining efficiency by instructing continuously both the fast and cutting feed modes and also connecting continuously the feeding speeds of both modes to each other with stopping both modes when they are set in the same direction. CONSTITUTION:A fast feed/cutting feed connection control part 6 checks the decoding result of an NC command program obtained by a program decoding part 1. Then the part 6 decides whether the continuous commands that do not care about the block order of the fast feed and cutting feed modes are set in the same direction or not. That is, the part 6 decides whether the stop processing is needed or not. If not, the part 6 performs no stop processing of the shift between the fast and cutting feed modes and continuously connects both feeding speeds to each other. Thus the part 6 controls motor 5 via an acceleration/ deceleration control part 2, an interpolation part 3, and a servo part 4. Thus, the speed can be smoothly changed and the waste time can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control method and apparatus for a numerically controlled machine tool, and more particularly to a speed control method and apparatus for a numerically controlled machine tool for improving machining efficiency.

[0002]

2. Description of the Related Art In numerically controlled machine tools, the machining efficiency is remarkably improved, and the rapid feed rate and the cutting feed rate are being increased. By the way, in the case of performing the machining in which the rapid feed and the cutting feed are continuous, as shown in FIG. 5, during the transition from the rapid feed to the cutting feed, the rapid feed deceleration,
After stopping and confirming the stop, the cutting feed is accelerated. This also applies to the transition from cutting feed to fast feed.

[0003]

As described above, in the conventional numerically controlled machine tool, it is necessary to perform deceleration stop, stop confirmation and acceleration without fail when performing machining in which rapid feed and cutting feed are continuous. However, in a machining command that continues from the fast feed to the cutting feed in the same direction, such deceleration stop and acceleration are obstacles to speeding up the fast feed and the cutting feed. For example, in a fixed cycle such as a deep hole machining cycle, rapid feed in the Z direction and cutting feed are frequently and alternately commanded, and rapid feed in the same direction and cutting feed are repeated many times, and the above-mentioned problem becomes prominent.

Therefore, an object of the present invention is to stop the axial feed at the transition between the rapid feed and the cutting feed when the rapid feed and the cutting feed are continuously commanded in any order and they are the feeds in the same direction. It is an object of the present invention to provide a speed control method and device for a numerically controlled machine tool that eliminates dead time as much as possible and improves machining efficiency.

[0005]

In order to solve the above-mentioned problems, a speed control method for a numerically controlled machine tool according to the present invention comprises:
When rapid feed and cutting feed are continuously commanded in any order and it is determined that they are feeds in the same direction, the feed speeds of the rapid feed and cutting feed can be set without stopping at the transition between rapid feed and cutting feed. It is configured to connect continuously. Further, in the speed control device for a numerically controlled machine tool according to the present invention, the first means for determining the type of the fast feed and the cutting feed and the feeding direction thereof, and the fast feed and the cutting feed are continuously performed by the first means in any order. Second command means for continuously connecting the feed rates of the fast feed and the cutting feed without stopping at the transition between the fast feed and the cutting feed when it is determined that they are feeds in the same direction. With.

[0006]

According to the present invention, when the rapid feed and the cutting feed are continuously instructed, it is not necessary to stop as in the transition from the rapid feed to the cutting feed or the transition from the cutting feed to the rapid feed. The processing efficiency is improved by smoothly setting the speed change between the current processing and the next processing, and connecting them.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a flowchart showing a processing procedure of a speed control method and apparatus for a numerically controlled machine tool according to the present invention. First, as a result of decoding the NC command program, the current block is fast-forward, the next block is cutting-feed,
It is determined whether these feed directions are the same (step S1). If YES is determined in step S1, the speed at the fast-forward end point position is set as the next block command cutting speed, and predetermined deceleration is performed (step S2). Next, the speed distribution at the cutting feed start point position is started at the command speed (step S3).

If NO is determined in step S1, it is determined whether or not the next block is fast-forward and in the same direction in the current block cutting feed (step S4). If YES here, the speed at the cutting feed end point position is set as the command speed (step S5), the speed distribution at the rapid feed start point position is set as the cutting feed end point position speed, and predetermined rapid feed acceleration is performed (step S6). On the other hand, in step S4, NO
If it is determined to be, deceleration, stop, and acceleration are performed as usual (step S7).

FIG. 2 shows an example of speed control of the above embodiment. In FIG. 2, fast forward with N1 block, N2
Cutting feed is performed by the block, cutting feed is performed by the N3 block, and fast feed control is performed by the N4 block. In addition, in FIG.
An NC program example of each block in FIG.

In FIG. 3, a movement from the current position is incrementally designated by G91, a fast feed (G00) and a fast feed target position (-100.000) are designated by a block N1, and a cutting feed (G01) is designated by a block N2. , The cutting feed speed (F4000) is specified, the reverse cutting feed target position is specified in the block N3, and the rapid feed (G
00) and the fast-forward target position (100.000) are designated.

The feed rate (absolute value) is controlled as shown in FIG. 2 in accordance with the command program shown in FIG. That is, at the time of transition from the rapid feed to the cutting feed, the rapid feed deceleration of the block N1 is started according to a predetermined deceleration curve so that the cutting feed speed becomes F4000 at the time point T2 when the cutting feed start position (the rapid feed target position: −100.000) is reached. The point T1 is determined, and the fast-forward deceleration is started from the time T1. In the transition from the cutting feed to the rapid feed of the block N3 to the block N4, the feed speed at the cutting feed end position is kept at F4000, and the acceleration of the rapid feed is commanded from there. As is clear from a comparison between FIG. 2 and FIG. 5, according to the present embodiment, the two feed rates are continuously connected without stopping during the transition between the rapid feed and the cutting feed, so that the machining efficiency is improved. To be done.

When continuous commands are issued in the same direction as the cutting feed from the rapid feed, the speed at the command end position of the rapid feed is set as the cutting feed speed instructed in the next block,
The vehicle decelerates according to the preset rapid traverse acceleration / deceleration curve. The cutting feed speed distribution at the starting point position of the next block is performed at the command cutting speed.

When the cutting feed is continuously commanded in the same direction as the rapid feed, the speed at the cutting feed command end position is set as the commanded feed speed, and the rapid feed start speed of the next block is set as the cutting feed. The speed is accelerated according to a preset fast-forward acceleration / deceleration curve to obtain a predetermined fast-forward speed.

FIG. 4 is a block diagram showing an example of a speed control device for a numerically controlled machine tool according to the present invention which executes the above processing. The NC command program is decoded by the program decoding unit 1, and the acceleration / deceleration control unit 2 outputs acceleration / deceleration control data based on the decoding result. The information decoded by the program decoding unit 1 is sent to the fast feed / cut feed combination control unit 6 and supplies the signals necessary for controlling the acceleration / deceleration control unit 2 to the acceleration / deceleration control unit 2.

The fast feed / cut feed combination control unit 6 judges whether or not it is necessary to stop at the time of transition of the processing from the current block to the next block as described above, and if there is no need to stop, the above-mentioned operation is performed. Processing, for example, deceleration control is started so that a predetermined speed is reached at the start of the next block. That is,
At the time of the process transition from the fast feed to the cutting feed or the process transition from the cutting feed to the fast feed, when the speed changes in the same direction, the stop process is not necessary. The signal from the acceleration / deceleration control unit 2 is subjected to interpolation processing by the interpolation unit 3 and then sent to the motor 5 via the operation of the servo unit 4.

[0016]

As described above, the method and apparatus for controlling the speed of a numerically controlled machine tool according to the present invention, when the rapid feed and the cutting feed are continuously commanded, at the transition from the rapid feed to the cutting feed or in the cutting feed. If there is no need to stop as in the transition from feed to fast feed, the dead time is eliminated by setting and connecting the speed change between the current process and the next process smoothly in time. Efficiency is improved, especially when performing deep hole machining cycles.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing procedure of a speed control method and apparatus for a numerically controlled machine tool according to the present invention.

FIG. 2 is a diagram showing a temporal change of a feed rate for explaining the operation of the embodiment of FIG.

FIG. 3 is a diagram showing an example of a command program for executing the processing of the embodiment shown in FIG.

FIG. 4 is a diagram showing a configuration example of a speed control device for a numerically controlled machine tool according to the present invention.

FIG. 5 is a diagram showing a change over time of a conventional feed speed.

[Explanation of symbols]

 1 Program Decoding Section 2 Acceleration / Deceleration Control Section 3 Interpolation Section 4 Servo Section 5 Motor 6 Fast Feed, Cutting Feed Coupling Control Section

Claims (4)

[Claims] 1. When fast feed and cutting feed are continuously commanded in any order and it is determined that they are feeds in the same direction, the fast feed and cutting are performed without stopping at the transition between the fast feed and the cutting feed. A speed control method for a numerically controlled machine tool, characterized in that the feed speeds of the feeds are continuously connected. 2. When changing from rapid feed to cutting feed, the rapid feed speed is decelerated according to a predetermined deceleration curve so that the feed speed at the command end position of the rapid feed becomes the commanded cutting feed speed, and the cutting is performed. The speed control method for a numerically controlled machine tool according to claim 1, wherein a feed speed at a feed start position is set as a commanded cutting feed speed. 3. When transitioning from cutting feed to rapid feed, the feed speed at the command end position of the cutting feed is set as a commanded cutting feed speed, and the rapid feed speed is set according to a predetermined acceleration curve from the cutting feed. The speed control method for a numerically controlled machine tool according to claim 1, wherein the speed is accelerated. 4. A first means for determining the types of fast feed and cutting feed and the feed direction thereof, and the fast feeding and cutting feed are instructed continuously by the means in any order, and they are in the same direction. And a second means for continuously connecting the feed speeds of the fast feed and the cutting feed without stopping at the transition between the fast feed and the cutting feed when it is determined to be the feed. Control machine tool speed control device.