JP2002132310A - Machine tool with automatic periodic examination function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machine tool having an automatic periodical examination function using CNC. SOLUTION: This machine tool has an examination reference value setting means which makes it possible to set an examination reference value even during automatic operation by judging information showing that the automatic operation is in process, information on whether or not there is an examination reference value, and periodic examination actuation request interval information in a period and at a position called by a periodic examination calling function capable of being optionally arranged in a machining program, a periodic examination executing means which performs periodic examining operation during the automatic operation, and an automatic periodic examination function actuating means composed of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machine tool, such as a machining center, which can automatically generate regular checkup information used for preventive maintenance even during continuous and automatic operation of the machine.

[0002]

2. Description of the Related Art Conventionally, in the field of preventive maintenance of machine tools, a state in which an operator temporarily stops the machine by notifying a periodic inspection execution time for each item and automatically stopping the machine after the notification for the periodic inspection. After the periodic inspection has been carried out, the state of the machine has been judged, and the periodic inspection operation has been started to carry out the periodic inspection to carry out preventive maintenance of the machine.

[0003]

In the case of carrying out a checkup by periodically stopping the machine for the purpose of preventive maintenance of the machine, especially when a continuous machine is used, it is necessary to perform a periodic checkup of a plurality of machines at once. It was difficult to actually perform the checkup work on a regular basis only with the notification of the inspection request because the person could not be secured. In addition, the operator judged whether maintenance work was necessary or not by inspection. Furthermore, if the continuous or automatic operation of the machine tool is temporarily stopped for the purpose of periodic inspection for diagnosing the necessity of maintenance, not for performing the intended maintenance work, there is a problem that the operation rate is reduced.

[0004] The operating condition including the trajectory during machining of a machine greatly changes depending on a jig installed on the machine, a workpiece carried into the machine, and a machining program of a customer. There is no uniform routine screening measurement operation and screening data collection method that can ensure measurement accuracy and reliability. Therefore, there has been a demand for a setting means capable of automatically responding to the operating state of the machine for a screening operation and a screening data collection method that are automatically executed.

[0005] Although the state of the machine is diagnosed based on the examination data, it is not easy to retrospectively analyze the aging state of the machine only by the examination data and the diagnosis result generated at the time of executing the examination. Also, if there is a history of examination data obtained by regular examinations, it is possible to grasp the aging status of the machine before the occurrence of a warning state (inspection request), making planning for preventive maintenance easier. there were.

Examination of positioning play which leads to deterioration of positioning accuracy due to loosening of couplings and ball screw nuts caused by aging or abnormality of the machine in the connection and support parts of the feed shaft ball screw, and deterioration of positioning accuracy due to wear of the ball of the ball screw support bearing. However, there has been a problem that it is desired to achieve reliability and durability without using a dedicated hardware device and to realize the same at low cost.

SUMMARY OF THE INVENTION It is an object of the present invention to diagnose a warning state before a machine is seriously damaged, and to perform a checkup operation which can be easily prepared in advance according to the operation state of the machine during the automatic operation of the machine. Machine tool having an automatic periodic check-up function capable of automatically generating preventive diagnosis information from the obtained periodic check-up history data. A machine tool having an automatic periodic medical check function with high reliability, durability and preventive maintenance efficiency is provided without installing a dedicated device as a medical check means.

[0008]

At the time and position called by the periodic examination calling function which can be arbitrarily arranged on a machining program, information on automatic driving, information on presence / absence of a screening reference value, and information on a request for starting regular examination are determined. Then, a screening standard value setting unit that enables setting of a screening standard value during automatic driving, a periodic screening execution unit that executes a periodic screening operation even during automatic driving, and an automatic periodic screening function constituted by them This is a machine tool having an automatic periodic examination function provided with means.

A description will be given based on the system configuration of FIG. 1 corresponding to an embodiment of the present invention. It utilizes a CNC device necessary for machine operation control and an LCD display with a touch panel function attached to the CNC. Mechanically, it is a simple hardware configuration that uses a stopper surface for setting the origin on the feed shaft butting type. A manual push button function for enabling operation and setting of the periodic examination function and means for displaying examination history data are provided on the screen of the display. In the program memory of the CNC, automatic periodic examination starting means that can be arranged on the processing program and examination reference value setting and examination program that can be executed by the automatic examination function or the manual push button function are arranged, and the examination measurement operation and measurement data There is provided a setting unit capable of easily creating collection conditions. After reading various data from the system variable area of the CNC as necessary, the examination history means and the history diagnosis means having the function of shifting the history data to the examination history data arranged in the user memory area and shifting the history data are also fixed macros. It is arranged on the program memory of the CNC in the form of a program. However, the load measurement and examination unit is arranged in the ladder program area of the PMC (sequencer with a built-in CNC) because high speed is required in collecting measurement data.

[0010]

FIG. 1 shows a system configuration corresponding to an embodiment of the present invention. The automatic periodic examination function activation means will be described with reference to FIGS. In FIG. 1, an automatic periodic examination calling function to which a regular examination activation interval parameter that can be arranged at an arbitrary position on the (processing) program is prepared. As shown in FIG. 2, the automatic periodic examination function which is called is an effective function after judging whether or not the machine is in automatic operation for ensuring the safety of the worker. If the screening reference value has not been set, the screening reference value setting function is called and the number of regular screening calls is cleared after the regular screening is called and the number of regular screening calls is calculated automatically. A periodic examination execution means is provided which determines the regular examination request information based on the number of examination calls or the interval time, calls the regular examination execution function, clears the number of regular examination calls, and automatically calculates the next regular examination time. By means of these means and the automatic periodic check-up activation means constituted by the automatic periodic check-up function arranged on the (processing) program, a periodic check-up can be performed from an arbitrary position specified on the (processing) program even during automatic operation. It becomes executable.

The details of the examination operation setting means by the measurement operation setting means and the measurement data collection setting means in the case of the load measurement execution subroutine (SR) shown in FIG. 1 will be described with reference to FIG. 3 corresponding to the embodiment. The measurement execution SR is roughly divided into a measurement operation setting SR and a measurement operation program.

Regarding the measurement operation setting means, in the measurement operation program, all the unique information corresponding to the actual machine operating condition used is handled as an independent parameter variable for each item, so that the program contents can be edited. However, it is basically fixed. In the (load) measurement operation setting subroutine program arranged immediately before, variables corresponding to each parameter variable are declared in advance. The user can respond to the actual machine operating condition by changing the values of these variables as necessary.

The measurement data collection setting means includes parameter variables (load) measurement data collection condition setting in which various (load) data are collected in the measurement operation program so as to be adapted to machine operation conditions. Subroutine call function (G171) is arranged.
As a function, it is possible to set the sampling environment of the measurement data and to record the weighted average value of the sampling data as measurement data, so that the measurement value can be specified arbitrarily and the measurement value reduced It is possible to secure. A subroutine call for repeatedly setting measurement data collection conditions is arranged in the measurement operation program, but parameter variable numbers are assigned independently for each measurement item, and the parameter variables used here are also the same as those described above (load).
Since the corresponding variables are all defined by the measurement operation setting subroutine program, the setting means can be changed from outside.

With respect to the examination operation setting means, the variable value for setting the examination operation is C by these examination operation setting means.
It is possible to set in advance from the LCD display using the NC MDI (manual data input) function, but before the automatic periodic check function call block in the processing program, etc. By performing setting without interference corresponding to the tool, it is possible to execute the examination operation setting corresponding to the operation state of the machine even during the execution of the automatic operation.

The examination data history means will be described with reference to the block diagram of the examination data history means of FIG. The medical examination data history is basically data obtained by taking various (measurement) data from the system variable memory area of the CNC and storing the data in the user memory area of the CNC. Machine coordinate position data is directly fetched from CNC system variables by a machine coordinate reading function on a program. Since the load data requires a high speed of the data taking operation during the execution of the machining program of the CNC, the processing structure is designed to take in the PMC program at a higher speed from the CNC program via the M code (M152). In addition to the measurement data, examination result and examination time data are added to the history data. The shift (update) function of the examination history data is performed by using instructions (M154 or G) created and arranged on the CNC program.
176). In the embodiment, the latest four times of history data are always stored for effective use of the CNC user memory area, and data before that is discarded at the time of shift of examination data.

The examination history data display means and various data setting means will be described together with the embodiment of FIG. These history data are stored in C that controls the machine body.
A user screen was created and displayed on an LCD display with a touch panel function of NC. The latest four times of the examination history data are displayed with the examination execution time data and the examination result added so that the aging state of the machine can be easily grasped.
In the case of a machine warning state as a result of the examination, a lamp is turned on in the measurement value column. Blinks when the following warning status automatic prediction is adopted. In addition, in the state of the regular checkup warning, the fact that there is data of the warning state is displayed on the main menu screen of the user screen. The push button functions for executing various programs are arranged on the touch panel, and the fields of the reference value, the warning ratio, and the allowable value can be set on the touch panel. A value obtained by multiplying a reference value by a warning ratio or a value obtained by adding or subtracting an allowable value to or from a reference value is defined as a screening warning value. In the operation of the [Perform Regular Examination] and [Measurement of Reference Value] push buttons for manual adjustment on the touch panel, it is considered that the history data shift is not performed so that valuable past data is not inadvertently discarded. [Measurement of reference value] The data measured by the push button function is displayed in the column of 1ST,
[Adoption of reference value] The value can be collectively registered in the reference value column by a push button function.

A means for automatically predicting and diagnosing a machine warning state based on examination history data will be described with reference to FIG. The warning threshold value A of each measurement item of the regular checkup is described as an example of a warning threshold value that becomes a warning state when the measured value is larger than the warning threshold value for the following description. Or < In the case of the normal periodic checkup function, if the measured value of the nth time of the periodic checkup is Yn, Yn> A --- (1) (1) When the formula (1) is satisfied, it is diagnosed that the present checkup measured value is in a warning state. . In the means for automatically predicting a warning state based on the periodic examination history data, the next periodic examination measurement value Y is obtained based on the regular examination history data.
When n + 1 is interpolated and estimated by the function f, Yn + 1 = f (Yn, Yn-1, Yn-2, Yn-3)> A --- (2) As an example, Yn + 1 is the historical data of Yn and Yn-1. When interpolation is estimated using a linear function, Yn + 1 = 2Yn-Yn-1> A-(2) 'When the expression (2) is satisfied, it is diagnosed that the next checkup measurement value warning is predicted. By using the regular checkup history data in this way, it is possible to interpolate the next regular checkup state using an approximate function. Analyzes the aging of the machine to some extent automatically and predicts the warning status before the generation of the screening warning data,
Automatic predictive diagnosis of a warning state based on periodic medical check history data that facilitates a preventive maintenance plan is possible.

The positioning play detection means for the feed shaft supporting part will be described with reference to FIG. 5 corresponding to the embodiment. By using a stopper for the method of setting the abutment origin of the machine, a means for determining the mechanical coordinate value of the stopper surface by abutting the movable part of the machine against the stopper is provided. The difference from the machine coordinate value of the stopper surface at the time of the regular checkup is calculated, and the difference is compared with the allowable value of the positioning play to make a diagnosis.

The means for determining the machine coordinate value of the stopper surface will be described in order along with the contents of the positioning play measurement execution subprogram. Various parameters required for the following positioning operation are set in the positioning operation setting subroutine. To avoid mechanical interference, the tool is indexed based on the parameters and the measuring axis is moved to the start position. Ignore the overtravel soft limit (excessive limit) function, which is an obstacle when hitting the stopper surface, and enable the torque limiting function to prevent the servo current from being excessive and hit the stopper surface with appropriate torque. Positioning is performed at the end point a machine coordinate value in consideration of the abutting margin which always hits the stopper surface. After the positioning is completed, the servo deviation is read from the CNC system variables to calculate the mechanical coordinate value of the stopper surface. Return from the stopper surface to the measurement start position. Enable the soft limit function and disable the torque limit function.

[0020]

Advantages of the Invention (1) Periodic medical examination can be performed during automatic operation by means of the periodic medical examination start-up means during automatic operation. Therefore, a decrease in the operating rate due to forgetting to perform a regular medical examination or stopping the machine at the time of regular medical examination is prevented, and preventive maintenance efficiency is improved. Become. (2) With the measurement operation setting means, it is possible to easily create a screening operation setting without mechanical interference corresponding to the machined workpiece or jig on the CNC machining program, and there is no setup in a continuous machine compatible with many models. This makes it possible to perform efficient periodic examinations during automatic driving. (3) The degree of freedom of the load measurement method and the reliability of data are improved by the measurement data collection condition setting means. (4) It is possible to analyze and grasp the secular change of the machine at any time by means of the regular examination history means and display means. (5) Preventive maintenance diagnosis ability is improved by the automatic warning state predictive diagnosis means based on the periodic examination history data, and a preventive maintenance plan can be set with a margin. (6) The positioning play of the machine tool using the CNC can be diagnosed at low cost by securing the reliability and durability by the positioning play detecting means.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of the present invention.

FIG. 2 is a flowchart of an automatic periodic diagnosis function activation unit.

FIG. 3 is a flowchart of measurement operation setting means and measurement data means.

FIG. 4 is an operation diagram of a warning prediction diagnosis unit.

FIG. 5 is a flowchart of positioning play detection means.

FIG. 6 is a display diagram of a screen 1.

FIG. 7 is a display diagram of a screen 2;

[Explanation of symbols]

 SR measurement execution G171 Subroutine call function MDI Manual data input

Claims (4)

[Claims] At a time and a position called by a periodic examination calling function which can be arbitrarily arranged on a processing program, automatic running information, examination reference value presence / absence information and regular examination start request interval information are judged, and the automatic examination is performed. It is provided with a screening standard value setting unit that enables setting of a screening standard value even during driving, a periodic screening executing unit that executes a periodic screening operation even during automatic driving, and an automatic periodic screening function starting unit configured from them. Machine tool with automatic periodic checkup function. 2. A machine tool having an automatic periodic medical checkup function comprising means for setting an arbitrary medical checkup operation corresponding to the operating condition of a machine by a measurement operation setting means and a measurement data collection condition setting means. 3. Examination data history means for adding the examination execution time data to the regular examination measurement data and examination result to record the examination data, examination history display means including (inspection request) warning, and automatic machine warning state based on the history data. A machine tool having an automatic periodic checkup function provided with predictive diagnosis means. 4. A mechanical stopper is provided at a stroke end of a mechanical feed shaft, and a soft limit function is disabled by using a CNC torque limiting function and a soft limit (valid / invalid) switching function of the feed shaft. By means of calculating the machine coordinate value of the stopper surface from the coordinate value of the machine positioning end point and the servo deviation amount where the movable part of the feed shaft is abutted against the stopper surface, the preset reference value of the stopper surface examination and the time of the periodic examination A machine tool having an automatic periodic check function provided with a play check device for positioning of a feed shaft supporting component that calculates a difference from a measured value as a positioning play amount.