JPH0360954A - Tool service life managing method - Google Patents

Abstract

PURPOSE:To know an accurate tool service life based on the actual using state of the tool by a method wherein a moving amount during the cutting is calculated and based on the moving amount, the tool service life is estimated. CONSTITUTION:A cutting distance of a tool is calculated by a processor 11, and based on the calculated cutting distance, a present tool life is computed. By comparing the present service life with a set value, the life is controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tool life management method for a numerical control device (CNC) that manages the tool life of a machine tool, and in particular, to a tool life management method that improves the accuracy of life values. Concerning lifespan management methods.

[Conventional technology]

Numerical control devices (CN, C) manage the tool life of the machine tool in order to maintain machining accuracy and prevent tool damage. For example, the number of executions of the NC program is accumulated, and when a set number of executions is reached, a command to change tools is issued. There is also a method of managing tool life by accumulating the actual usage time of the tool.

[Problem to be solved by the invention]

However, since the conditions in which the tool is used differ depending on the machining process, N
It is not possible to accurately determine the lifespan value simply by adding up the number of executions of the C program. In addition, even if the tool operating time is accumulated, if the cutting speed is overridden, the actual cutting load will increase but the operating time will be measured less, so the life value data will not reflect the actual value. will display the opposite result.

The present invention has been made in view of these points, and an object of the present invention is to provide a tool life management method that improves the accuracy of life values.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a tool life management method for a numerical control device (CNC) that manages the tool life of a machine tool by calculating the cutting distance of the tool. , there is provided a tool life management method characterized in that the tool life is managed by calculating a current tool life value based on the calculated cutting distance and comparing the current life value with a set value. Ru.

[Effect]

By calculating the amount of movement during cutting and determining the life value based on this, the tool life can be managed without being affected by changes in cutting speed during machining.

〔Example〕

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

Figure 2 shows a numerical control device (CNC) for implementing the present invention.
) is a block diagram of the hardware.

In the figure, the processor 11 is connected to the ROM via the bus 21.
The system program stored in the computer 12 is read out, and the entire operation of the numerical control device 10 is controlled in accordance with this system program. DRAM is used for RAM13,
- Temporal calculation data, display data, etc. are stored. The non-volatile memory 14 is composed of a CMOS, is backed up by a battery (not shown), and stores tool life values, tool correction amounts, pitch error correction amounts, NC programs, parameters, etc., which will be described later.

The interface 15 is an interface for external devices, and external devices 31 such as a paper tape reader, a paper tape puncher, a paper tape reader/puncher, etc. are connected thereto. The NC program is read from the paper tape reader, and the NC program edited within the numerical control device 10 can be output to the paper tape puncher.

PMC (7' programmable machine controller) 1
6 is built into the numerical control device 10, and controls the machine side using a sequence program created in a ladder format. That is, the M function, S function, and 7 commanded by the NC program.
According to the function, the sequence program is converted into necessary signals on the machine side and output from the I10 unit 17 to the machine side. This output signal drives a magnet, etc. on the machine side, and operates a hydraulic valve, a pneumatic valve, an electric actuator, etc. It also receives signals from limit switches on the machine side, switches on the machine operation panel, etc., performs necessary processing, and passes them to the processor (1).

The graphic control circuit 18 converts digital data such as the current position of each axis, alarms, parameters, and image data into image signals and outputs the image signals. This image signal is CRT/MD
It is sent to the display device 26 of the I unit 25 and displayed.

The interface 19 receives data from the keyboard 27 in the CRT/MDI unit 25 and sends the data to the processor 11.
give it to

Interface 20 is connected to and receives pulses from manual pulse generator 32 . A manual pulse generator 32 is mounted on the machine operation panel and is used to manually move the machine moving parts precisely.

Axis control circuits 41-44 receive movement commands for each axis from processor 11, convert them into speed command signals, and output them to servo amplifiers 51-54. Servo amplifier 51-54
amplifies the speed command signal to drive the servo motors 61 to 6 of each axis.
Drive 4. The servo motors 61 to 64 have a built-in pulse coder for position detection, and a position signal is fed back from the pulse coder as a pulse train. In some cases, a linear scale is used as a position detector. Further, by performing F/V (frequency/velocity) conversion on this pulse train, a velocity signal can be generated. Additionally, a tacho generator may be used for speed detection. In the figure, these position signal feedback lines and velocity feedback lines are omitted.

The spindle control circuit 71 receives a spindle rotation command, a spindle orientation command, etc., and outputs a spindle speed signal to the spindle amplifier 72. The spindle amplifier 72 receives this spindle speed signal and
The spindle motor 73 is rotated at the commanded rotation speed. Further, the spindle is positioned at a predetermined position by an orientation command.

A position coder 82 is connected to the spindle motor 73 by a gear or a belt. Therefore, the position coder 82 rotates in synchronization with the spindle motor 73,
A feedback pulse is output, and the feedback pulse is read by the processor 11 via the interface 81. This feedback pulse is used to move other axes in synchronization with the spindle motor 73 to perform processing such as thread cutting.

Here, the above processor 11 calculates the tool life value by integrating the distribution pulses output from the interpolator during cutting,
Tool life management is performed by comparing this tool life value with a set value.

FIG. 1 is a flowchart of tool life management.

In the figure, the number following S indicates the step number.

[S1] It is determined whether the current program is cutting or simply positioning.

In the case of cutting, the process proceeds to S2, and in other cases, the process ends.

[S2] The cutting distance is determined by integrating the distributed pulses from the interpolator.

[S3] The cutting distance obtained in S2 is added to the previous tool life value stored in the nonvolatile memory, and this is set as the current tool life value.

[S4] Determine whether the tool life value exceeds the set value. If it does, proceed to S5; if it does not, the process ends.

[S5] Determine whether there is an unused substitute tool. If there is, go to S6; if not, go to S7.

[S6] Command to replace the tool whose life has expired with an alternative tool registered in advance in the non-volatile memory.

[S7] Display an alarm on the display screen to the effect that alternative tools are exhausted.

The above processing is performed between interpolation and movement command processing to manage tool life.

〔Effect of the invention〕

As explained above, in the present invention, the amount of movement during cutting is calculated and the tool life value is determined based on this, so accurate tool life values can be obtained in accordance with the actual usage conditions of the tool, and reliability can be improved. High lifespan management is possible.

[Brief explanation of drawings]

FIG. 1 is a flowchart of a tool life management method according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a numerical control device for implementing the present invention. 10 Numerical control device 11 Processor 14 Non-volatile memo 26 Display device

Claims (5)

[Claims] (1) Numerical control device that manages the tool life of machine tools (
CNC) tool life management method, by calculating the cutting distance of the tool, calculating the current tool life value based on the calculated cutting distance, and comparing the current life value with a set value. A tool life management method, characterized in that the tool life is managed. (2) The tool life management method according to claim 1, characterized in that when the life value exceeds the set value, a command is given to replace the tool with an alternative tool. (3) The tool life management method according to claim 2, further comprising displaying an alarm on a display screen when the alternative tool runs out. (4) Store the previously calculated lifespan value in non-volatile memory,
2. The tool management method according to claim 1, wherein the current life value is determined by adding the currently calculated cutting distance to the life value stored in the nonvolatile memory. (5) The cutting distance is obtained by integrating distribution pulses output from an interpolator.
Tool life management method described in section.