JPS61201157A - Tool breakage detecting device - Google Patents

Abstract

PURPOSE:To enable only a specified user to adjust the sensitivity of an AE sensor in a tool breakage detecting device having an AE (acoustic emission) sensor by providing means for recognizing the user's password. CONSTITUTION:A work 1 is machined on a ball m ill by a drill by means of a numerical control device 3. The AE sensor 6 is provided near the tool, the AE signal is amplified by a signal processing part 7 and transmitted to a CPU 9 for displaying at 13 the abnormal machining or detected tool breakage. When the user executes sensitivity adjustment of the AE sensor, the inputs a password to a program console 14 for collating with the password previously recorded in the numerical control device 3. Sensitivity adjustment is enabled in case cooincidence exists. Pseudo signals of a level corresponding to the tool is produced in a generator 4, and transmitted to the AE sensor 6 and the amplification factor of the device 7 is adjusted in the CPU 9. The AE sensor sensitivity for the tool is set and machining is executed with the pseudo signal generator removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention monitors tool breakage and foreign parts in machine tools by using acoustic emission (hereinafter referred to as AE) generated during cutting and breakage.

The present invention relates to a tool breakage detection device that automatically detects tool breakage, and particularly to a tool breakage detection device that is characterized by sensitivity adjustment of an AE sensor.

[Summary of the invention]

The tool breakage detection device according to the present invention detects tool breakage by setting the AE sensor sensitivity for the tool used in advance, but when adjusting the sensitivity of the AE sensor, it is necessary to set the AE sensor sensitivity for the tool used in advance. This allows only the user who has entered the password to adjust the sensitivity of the AE sensor. In this way, you can accidentally get A.
The sensitivity of the E sensor is not changed, making it possible to improve the reliability of breakage detection.

[Prior art and its problems]

When a machine tool uses a tool to cut an object to be machined (hereinafter referred to as a workpiece), the tool may break for some reason or chips may accumulate, resulting in abnormal cutting. With the recent progress in factory automation, there is a strong demand for automatic detection of tool breakage and abnormal cutting. As a method for detecting tool breakage in machine tools, conventional methods have been to
An apparatus has been proposed that includes a sensor and detects tool breakage based on an AE multiplied signal obtained from the sensor.

Incidentally, there are a wide variety of tools used in machine tools, and the magnitude of the AE multiplied signal generated when the tools break varies over a wide range. Therefore, each time the tool is changed, the AE
Sensor sensitivity needs to be readjusted. Therefore, it is conceivable to have a sensitivity table in the storage means that stores the sensitivity of the AE sensor for each tool used in advance, and then automatically set the sensitivity depending on the type of tool. However, if a person other than the user carelessly changes the sensitivity setting value of the AE sensor, there is a problem that tool breakage cannot be detected with correct sensitivity.

[Purpose of the invention]

The present invention has been made in view of the problems of the tool breakage detection device, and provides a tool breakage detection device that allows only a specific user to set the sensitivity of the AE sensor and change the sensitivity value. The purpose is to

[Structure and effects of the invention]

The present invention is a tool breakage detection device that has an AE sensor installed near the tool of a machine tool and detects breakage based on an AE multiplied signal obtained when the tool breaks. A sensitivity adjustment means for adjusting the sensitivity, a storage means for storing a password arbitrarily determined by the user and the sensitivity of the AE sensor for each tool, an input means for inputting the password, and a storage means for storing the password input from the input means. and a signal processing section that detects tool breakage based on the output of the AE sensor. That is.

According to the present invention having such characteristics, the sensitivity value of the AE sensor and a predetermined password are stored in the storage means, and the sensitivity table of the AE sensor is read only when the password already registered there is input. It is possible to change. Therefore, since no one other than the operator who does not know the password can change the sensitivity table, the sensitivity of the AE sensor will not be changed inadvertently.

Therefore, by simply inputting the tool to be used, it is possible to always set the optimum sensitivity to the AE sensor from the sensitivity table, and it is possible to improve the reliability of tool breakage.

[Explanation of Examples]

(Overall Configuration of Embodiment) FIG. 1 is a block diagram showing an embodiment of a tool breakage detection device according to the present invention. This embodiment shows a tool breakage detection device attached to a drilling machine controlled using a numerical control device, in which a workpiece (2) is fixed on the base of the drilling machine, and a drill (2) is inserted from the top of the workpiece (1). The workpiece 1 is opened by rotating and pushing down at a predetermined speed. The operation of the drill 2 is controlled by a numerical control device 3. Now, place the workpiece 1 at the position where the drill bit on the top of the workpiece 1 makes contact.
Before cutting to the same <PZT as the AE sensor
A pseudo-breakage signal generator 4 consisting of the like is attached. The drive circuit 5 drives this pseudo-breakage signal generator 4, and is configured to oscillate a drive waveform that is similar to and has the same power spectrum distribution as the AE output waveform when the prewarming tool breaks. , its amplitude level is given externally. An AE sensor 6 for detecting the AE multiplied signal is provided near the tool on which the workpiece I is placed, for example, on the base as shown in FIG. The AE sensor 6 is a wideband AE sensor that detects an AE multiplied signal from a tool such as a drill 2 and an AE multiplied signal from the pseudo-breakage signal generator 4, and its output is given to an AE signal processing section 7. The AE signal processing section 7 is A
It has a variable amplification factor amplifier 7a that amplifies the signal from the E-sensor 6 to a predetermined level, and detects signals of tool breakage and abnormal cutting. (referred to as the CPU). Further, the CPU 9 sets the amplification factor of the variable amplification factor amplifier 7a as the sensitivity of the AE sensor 6. The CPU 9 stores a system control program and a communication control program with the numerical control device 3, and also has a ROM (hereinafter referred to as ROM) and a sensitivity table of the AE sensor corresponding to the tool used by the numerical control device 3, as well as a predetermined memory. Random access memory (RAM) has a password storage area for storing passwords of users who have been
11) is connected to the storage means. C.P.
The U9 also has a display 13 that displays the AE signal level during cutting, abnormal cutting or tool breakage via an input/output interface 12, and a display 13 that displays the level of tool breakage at a location remote from the main body, and displays the tool number and type. , a program console 14 for inputting the standard AE sensor sensitivity and password.
is connected. Furthermore, the numerical value side via the signal transmission line 15? ff1l Device 3 is connected. CPU9 is AE
Data is transmitted to the numerical control device 3 based on the breakage detection signal from the signal processing section 7, and ilJfa is performed to confirm whether or not the tool is broken. Further, the storage area for the sensitivity table of the AE sensor and the password can also be configured to be stored in the memory of the numerical control device 3.

(Configuration of Program Console) Next, FIG. 2 is a block diagram showing the configuration of the program console 14. In this figure, a line receiver 16 receives and receives signals from the human output interface I2 of the main body of the tool breakage detection device, and a line driver I7 sends signals.
is connected.

The program console 14 itself has a CPU 18, and is connected to a program ROM 19 as storage means and a buffer RAM 20 for temporarily holding manually input data. A keyboard 22 is also connected to the CPU 18 via a key interface 21 as a manual means for the program console 14 . The keyboard 22 is provided with a numeric keypad and function keys Fl to F6 for performing various operations, such as mode settings. The CPU 18 also includes a numerical display 24 that displays the amplification factor of the AE sensor 6, the drive level of the pseudo-breakage signal generator 4, etc. via a display driver 23, and a bar code display that displays the cutting level of the tool. A cutting level indicator 25 is connected.

(Password Confirmation Operation) Next, the process of confirming the password by the user and setting the sensitivity of the AE sensor will be described with reference to a flowchart. FIG. 3 is a flowchart showing the operation of the program console 14, and FIG. 4 is a flowchart showing the operation of the main body of the tool breakage detection apparatus. In this case, it is assumed that the password is stored in the memory within the numerical control device 3.

Now, in step 30 shown in FIG. 3, when the user inputs a password consisting of a numerical string arbitrarily determined by the user from the keyboard 22 of the program console 14, the CPU 18 temporarily stores the data in the HASOFA RAM 20.
to hold. Then, the process proceeds to step 3132, where a password verification request is sent to the tool breakage detection device main body via the line driver 17, and a verification preparation signal is awaited. The CPU 9 of the main body of the tool breakage detection device waits for a password verification request signal in step 40, and when this signal is given, it requests the code transmission of the password registered in the numerical control device 3 (step 41). The process then proceeds to step 42 to check whether the password code has been received from the numerical control device 3, and returns to step 41 to continue requesting transmission until the password code is received. On the other hand, numerical control device ゛3
Based on a password code transmission request from the main body of the tool breakage detection device, the code corresponding to the password inputted from within the storage means is sent out. Then, the main body of the tool breakage detection apparatus proceeds to steps 43 and 44, sends a verification preparation signal to the program console 14, and waits for a large cover swap. Program console 14 steps 31.3
After the password transmission request is made in step 2, an immediate/$ ready signal is awaited, and when this signal is given, the process proceeds to step 33, where the code of the password input by the user is transmitted to the main body.

On the other hand, when the tool breakage detection device receives the input password from the program console 14, it proceeds to step 45 and compares it with the registered password sent from the numerical control device 3. If they do not match, a mismatch signal is sent to the program console 14.
(step 47) and returns to step 40. If the passwords match, the process proceeds to step 48, where a matching signal is sent to the program console 14 (step 48), and the process proceeds to routine 49, where sensitivity setting processing for the AE sensor is executed. On the other hand, the program console 14 receives the password verification result in step 34, and if the passwords do not match, the display 24 displays the password mismatch via step 35 in step 36, and the process returns to step 30. If the passwords match, the display 24 displays permission to change the sensitivity and proceeds to the sensitivity setting process of routine 38.

To set the sensitivity of the AE sensor, a pseudo-breakage signal generator 4 is attached to the workpiece 1, and the drive circuit 5 is driven according to a level input from the program console 14 that corresponds to the tool used. Then, a pseudo-breakage signal is transmitted from the pseudo-breakage signal generator 4 to the AE sensor 6 via the workpiece 1 and the head.

The CPL 19 adjusts the amplification factor to a predetermined value based on the output of the variable amplification factor amplifier 7a in the signal processing section 7. In this way, even if the AE multiplied signal attenuation rate is unknown due to the mounting condition between the tool and the AE sensor 6, it is possible to provide the signal processing unit 7 with a signal at the same level as when the tool is broken. In this way, the sensitivity table storing the sensitivity of the AIE sensor is set or modified for the necessary tool, the pseudo-breakage signal generator 4 is removed, and cutting is performed using the tool.

As described above, in the present invention, the user is confirmed using a password to prevent the sensitivity table of the AE sensor from being changed inadvertently.

In this embodiment, a pseudo breakage signal generator is used to set the sensitivity of the AE sensor, and a pseudo breakage signal is continuously generated, and the sensitivity of the AE sensor 6 is adjusted by the output of the variable gain amplifier 7a. It is also possible to adjust the sensitivity of the AE sensor using other methods and store it in a predetermined sensitivity table.

Furthermore, although this embodiment describes a tool breakage detection device applied to a drilling machine using a numerical control device, the tool breakage detection device according to the present invention can also be applied to other machine tools controlled by a numerical control device, such as lathes and milling machines. It is also possible to apply the present invention to large-scale machining centers.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the tool breakage detection device according to the present invention, Fig. 2 is a block diagram showing the configuration of the program console, Fig. 3 is a flowchart showing the operation of the program console, and Fig. 4 is a block diagram showing the configuration of the program console. 1 is a flowchart 1- showing the operation of the main body of the detection device. ]---Work 2------Drill 3------
-One numerical control device 4---Pseudo breakage signal generator
5----Drive circuit 6----A E sensor
7----A E signal processing unit 1a--Variable gain amplifier 8゜12-Person output interface 9
．． 18-CPU 10,19- ・-, ROM
11.20--RAM 13--Display 1 t--Program console 22
・−・・−Keyboard patent applicant Tateishi Electric Co., Ltd. agent Patent attorney Yoshiki Okamoto (1 person) Signal back Arashi 6-----・AEtnsa Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) In a tool breakage detection device that has an AE sensor installed near the tool of a machine tool and detects breakage based on an AE signal obtained when the tool breaks, the sensitivity of the AE sensor is determined based on the tool used. Sensitivity adjustment means for adjusting the password; storage means for storing a password arbitrarily determined by the user and the sensitivity of the AE sensor for each tool; input means for inputting a password; A control means for adjusting the sensitivity of the AE sensor by the sensitivity adjustment means when the password storage area of the storage means is compared with the password storage area, and a signal processing section for detecting tool breakage based on the output of the AE sensor. A tool breakage detection device characterized by: