JPH01300308A - Numerical controller for machine tool - Google Patents

Abstract

PURPOSE:To ensure the optimum control of the air cutting speed for a cutting, etc., by setting the tool moving speed at the maximum value in response to the relative distance. CONSTITUTION:A distance measuring device 1 irradiates a laser light beams, for example, onto the working surface of a work 8 and catches this reflected beam wave to measure the relative distance D between the work 8 and a tool 2. The result of this measurement is sent to a ladder processing part 5 and the override value is decided in accordance with the distance D. Then the movement of the tool 2 is started at a feeding speed decided by correcting a programmed cutting speed. Thus, the first programmed feeding speed is corrected and furthermore the tool 2 is moved for an obtained distance in the minimum time. Then the working cycle is easily shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Use) The present invention relates to a numerical control device for a machine tool that controls cutting operations and the like using a computer.

(Prior Art) In a machine tool that performs normal cutting, it is possible to override the cutting speed as appropriate in order to shorten the so-called air cut time in which the tool is fed in an idle manner.

In other words, by overriding the cutting speed of the tool according to the shape of the workpiece, the tool can be fed at high speed, minimizing the machining cycles of machine tools operated under the same control program, and improving workpiece machining efficiency. I try to do that.

(Problem to be solved by the invention) In control using such a conventional numerical control device, the moment when the tool comes into contact with the cut surface of the workpiece is detected using, for example, a pressure sensor, and the override is canceled based on that. I try to do that. However, since the override amount is fixed and set regardless of the distance between the tool and the workpiece, if the speed increases, the workpiece or tool, especially the tip of the cutting tool, will be damaged and subsequent machining will be interrupted. Therefore, there was a problem that the air cutting speed could not be set sufficiently high, and furthermore, the cutting became rough immediately after the tool came into contact with the workpiece.

The present invention was made to solve the above problems, and
The object of the present invention is to provide a numerical control device for a machine tool that can optimally control the speed of air cutting in cutting operations.

(Means for Solving the Problem) According to the present invention, in a numerical control device for a machine tool that forms a control command for relatively moving a workpiece and a tool to perform predetermined machining based on a machining program, the tool a measuring means that moves together to measure the relative distance between the workpiece and the tool, and a changing means that changes the air cut movement speed included in the control command based on the measurement result, and changes the moving speed of the tool 8 to the It is possible to provide a numerical control device for a machine tool, characterized in that the value is set to a maximum value depending on the relative distance.

(Function) The machine tool numerical control device of the present invention measures the air cut feed distance in advance or every moment, and controls the machine tool at the air cut movement speed calculated based on the measurement results. I am trying to output commands.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In the drawing, a non-contact distance measuring means 1, such as a laser transmitter or an ultrasonic measuring device, is connected to a chuck part 3 of a cutting tool 2.
An example of the configuration of a system is shown in which the measurement results are transferred to the ladder processing section 5 of the NC device 4. The NC device 4 is a CNC configuration including a microcomputer and the like, and forms control commands for performing predetermined machining on a workpiece based on a machining program. Here, a drive command for driving the servo motor is outputted via the speed amplifier 6, and the table 9 of the machine tool on which the workpiece 8 is placed is controlled to move at a predetermined speed to a predetermined position.

The NC device 4 is provided with an override means for changing and setting the eight motion speeds of the tool 2 specified by the loaded machining program at a predetermined rate. In addition to switching, settings can be changed automatically based on commands from the ladder processing section 5.

For this purpose, the memory in the NC device 4 stores a table for setting parameters for the override amount based on the transferred distance data.

Note that the result of measuring the distance between the bite tool 2 and the workpiece 8 is transferred as a digital value, but is not transferred to the NC device 4.
It is also possible to send the data continuously during the air cut feed prior to the start of processing, in response to a request from the company, and the data transfer method may be wired or wireless.

In the system configured as described above, an operation for optimizing air cut control during cutting will be described next.

When starting cutting according to the machining command program decoded by the NC device 4, the distance measuring means 1 irradiates, for example, a laser beam onto the machining surface of the workpiece 8, captures the reflected wave, and connects the workpiece 8 and the tool. Measure the relative distance lID with 2. The measurement results are transferred to the ladder processing section 5, and the distance! 1
The set override amount is determined according to tD, and tool movement is started at the feed rate that is the corrected cutting speed that has been programmed. In this case, it is also possible to set a speed curve for minimizing the air cut time of the tool 2 and sequentially change the override amount accordingly.

In this way, the initially programmed feed rate is corrected and the tool 2B is moved over the determined distance in the shortest time, making it easy to shorten the machining cycle. Furthermore, compared to the case of using a conventional contact type sensor, damage to the tool 2 and workpiece 8 can be reliably prevented, and
The override amount is automatically changed. Therefore, when creating a machining program, all you need to do is set the mode specification as an auxiliary function code and insert it into the first block of the machining cycle. Therefore, N
The efficiency of C operation will also be improved. Furthermore, it works effectively even when the workpiece position is not constant when the workpiece 8 is supplied from a robot to a machine tool.

As above, this invention has been described in some detail with respect to its most preferred embodiment, but the description of the preferred embodiment does not include variations in detailed parts of the configuration or contrary to the spirit of the invention as described in the claims. It is clear that various modifications or combinations thereof may be made.

(Effects of the Invention) As explained above, according to the present invention, by setting the tool B moving speed to the maximum value according to the relative distance, it is possible to optimally control the speed of air cutting in cutting, etc. We can provide numerical control devices for machine tools.

[Brief explanation of the drawing]

The drawing is a block diagram showing one embodiment of the present invention. l... Distance measuring means, 2... Tool, 4... NC device. Patent applicant: FANUC Corporation Representative Patent Attorney Minoru Tsuji

Claims (2)

[Claims] (1) In a numerical control device for a machine tool that generates control commands for relatively moving a workpiece and a tool to perform predetermined machining based on a machining program, the device moves together with the tool to control the relative distance between the workpiece and the tool. The tool includes a measuring means for measuring, and a changing means for changing the air cut moving speed included in the control command based on the measurement result, and the tool moving speed is set to a maximum value according to the relative distance. A numerical control device for machine tools characterized by the following. (2) The apparatus according to claim (1), further comprising a speed setting means for overriding a speed command based on the control command, and a calculation means for setting a parameter of an override amount based on the measured distance. numerical control device for machine tools.