JPH0240701A - Block overlap system - Google Patents

Abstract

PURPOSE:To shorten the cycle time of a work by starting commands for a next block before a decelerating speed becomes zero after the interpolation of a current block by the block overlap system of a CNC machine tool. CONSTITUTION:An interpolating means 1 performs interpolation at a commanded speed Fi, outputs distribution pulses for X-axial and Y-axial speeds FXi and FYi, and outputs a signal IF after the interpolation. Then X-axial and Y-axial accelerating and deceleration means 2 and 3 accelerate distribution pulses of the axes and output the distribution pulses of the axes to set the speeds to FX and FY. A command start decision means 4 after receiving the signal IF from the means 1 outputs a start command signal NBS for starting the commands for the next block according to a preset program and preset parameters after a specific speed is reached or at specific time. Consequently, the execution time between blocks and then the cycle time of the work can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a block overlap method for CNC machine tools, and more particularly to a block overlap method improved to shorten machining cycle time.

[Conventional technology]

, CNC machine tools such as small automatic lathes process many of the same workpieces, so there is a need to shorten the machining time for one workpiece and process more workpieces within a set time. Ru. As a result, improvements have been made to acceleration/deceleration curves, etc., and machining cycles have been shortened.

The command for the next block is started after the deceleration of a specific axis is completed. As a result, it is thought that there is considerable wasted time during this period.

The present invention has been made in view of these points, and it is an object of the present invention to provide an improved block overlap method so as to shorten the machining cycle time.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a block overlap system for CNC machine tools, which is characterized in that after the interpolation of the current block is completed, commands for the next block are started before the deceleration speed reaches zero. An overlap method is provided.

[Problem to be solved by the invention]
[Effect] However, when the deceleration speed of the currently commanded block reaches zero, the interpolation of the current block ends and the command of the next block is started before the deceleration speed of the currently commanded block reaches zero. start, save time between blocks and shorten machining cycles. At what point the pulse distribution of the next block's command is started will be explained in detail in the following embodiment.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a schematic block diagram of a numerical control device for implementing the present invention. In the figure, 1 is an interpolation means,
Interpolation is performed at the commanded speed Fi, and a distribution pulse for the X-axis speed Fxi and a distribution pulse for the Y-axis speed Fyi are output, respectively. When interpolation is completed, an interpolation end signal IF is output.

Reference numeral 2 denotes an X-axis acceleration/deceleration means, which accelerates and decelerates the X-axis distribution pulse and outputs the accelerated/decelerated X-axis distribution pulse, whose speed is Fx. Reference numeral 3 denotes a Y-axis acceleration/deceleration means, which accelerates/decelerates the Y-axis distribution pulse and outputs the accelerated/decelerated Y-axis distribution pulse, whose speed is Fy.

Reference numeral 4 denotes a command start determination means, which after receiving the interpolation end signal IF from the interpolation means 1, generates a start command signal NBS for starting the command of the next block based on the speed of the distribution pulse of the X-axis or Y-axis, etc. Output.

The point at which the next block is commanded will be described below.

First, the next command is started when the deceleration speed of the current block reaches a constant value. FIG. 2 shows the relationship between the first speed and the start of the next command. In the figure, the horizontal axis is time, and the vertical axis is the speed of each axis. Fxi is the interpolation speed of the X axis,
Fx is the speed of the accelerated or decelerated X-axis. That is, at time Tt, interpolation of the command of the current block is started by the interpolation means 1, and the distribution pulse is accelerated/decelerated controlled by the X-axis acceleration/deceleration means 2 and follows at the speed Fx. At time T2, the interpolation by the interpolation means 1 ends, an interpolation end signal IF is output, and the X-axis speed Fx starts decelerating.

At time T3, the speed becomes Fd, and the command start determination means 4 outputs the next command start command signal NBS when the interpolation end signal IF and the X-axis deceleration speed become Fd, and the next command starts. Then, interpolation on the X axis is started, the speed becomes constant at time T4, the interpolation ends at time T, and the speed becomes zero at time T6.

Of course, if there is a next block, the instruction for the next block will be started before the speed Fx becomes zero.

The speed Fd for determining the start of the command for the next block may be set in advance as a parameter in the memory within the numerical control device, or may be directly commanded by a program.

Figure 3 shows the relationship between the second speed and the start of the next block. Figure 3 differs from Figure 2 in that the next block command is a Y-axis command, and the X-axis interpolation is performed at time T2. is completed, the speed Fx is decelerated, reaches the speed Fd at time T, and Y-axis interpolation of the command of the next block is started. At time T4, the X-axis speed Fx becomes zero. Fyi is the interpolation distance of the Y-axis, and py is the speed of the Y-axis under acceleration/deceleration control. And time T.

The Y-axis interpolation ends at T, and the speed becomes zero at time T.

Next, a case will be described in which the command for the next block is started at a predetermined time. In FIG. 4, which shows the relationship between the third speed and the start of the next block, the command for the next block starts at time T, which is a time ta after the end of the X-axis interpolation.

Further, as shown in the figure, the next command can be started at time T, which is a time tb before time T4 when the X-axis speed Fx becomes zero.

The time ta or tb for determining the start of the command for the next block may be set in advance as a parameter in the memory within the numerical control device, or may be directly commanded by a program.

In the above explanation, the next block's command is an axis movement command, but even if it is a command for M function, 1 function, etc., the command of the current block must be executed before the speed after acceleration or deceleration of the axis becomes zero. By executing these M functions or one function every time, the cycle time can be shortened.

By implementing the present invention, it was possible to shorten the cycle time of a certain workpiece from about 7 seconds to about 6 seconds.

Further, in the above description, the axes were described as the X-axis and the Y-axis, but the present invention is not limited to these axes, and can also be applied to a CNC machine tool having three or more axes.

FIG. 5 shows a schematic hardware configuration diagram of a numerical control device for implementing the present invention. In FIG. 0, 11 is a processor that controls the entire numerical control device, and 12 is a ROM in which a system program is stored.

13 is a RAM in which various data are stored.

14 is a display device, and a CRT or the like is used. 15 is a non-volatile memory that stores the program and parameters Fd, t.
aS tb, etc. are stored. 16 is the operation panel, 17
is a machine tool.

[Effects of the Invention] As explained above, in the present invention, the command for the next block is started before the axis speed of the current block becomes zero, so the execution time between blocks is shortened, and the workpiece cycle time can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a schematic block diagram of a numerical control device for implementing the present invention, Fig. 2 is a diagram showing the relationship between the first speed and the start of the next command, and Fig. 3 is a diagram showing the relationship between the second speed and the next command. FIG. 4 is a diagram showing the relationship between the third speed and the start of the next block. FIG. 5 is a schematic diagram of the hardware configuration of a numerical control device for implementing the present invention. It is a diagram. 1.--.-.--.-- Interpolation means 2 X-axis acceleration/deceleration means 3 Y-axis acceleration/deceleration means 4 Command start determination means 11 Processor 12.・ROM13
RAM Display device - non-volatile memo operation panel machine tool Patent applicant: FANUC Co., Ltd. Representative Patent attorney: Takeshi Hattori Figure 5

Claims (10)

[Claims] (1) In the block overlap method of CNC machine tools, the block overlap method is characterized in that after the interpolation of the current block is completed, commands for the next block are started before the deceleration speed reaches zero. (2) The block overlap method according to claim 1, wherein the command for the next block is started when the deceleration speed of the current block reaches a predetermined speed. (3) The block overlap method according to claim 2, wherein the predetermined speed can be commanded by a program. (4) The block overlap method according to claim 2, wherein the predetermined speed is set by a parameter. (5) The block overlap method according to claim 1, wherein the command for the next block is started when the deceleration time of the current block has elapsed for a predetermined time. (6) The block overlap method according to claim 5, wherein the predetermined time can be instructed by a program. (7) The block overlap method according to claim 5, wherein the predetermined time is set by a parameter. (8) The block overlap method according to claim 1, wherein the command for the next block is started a certain period of time before the end of deceleration of the current block. (9) The block overlap method according to claim 8, wherein the certain time period can be commanded by a program. (10) The block overlap method according to claim 8, wherein the certain time period is set by a parameter.