JPS6179160A - Tool breakage detecting device with self-diagnostic function - Google Patents

Abstract

PURPOSE:To provide a self-diagnostic function by outputting a signal indicating a signal which is transmitted continuously all the time is not received if a device which senses the continuously transmitted signal and decides on normality is abnormal. CONSTITUTION:For example, when a drill 4 is abnormal, the waveform of a generated AE (acoustic emission) wave is checked by a tool abnormality detection sensor 1 and an arithmetic part 2 makes a decision. Further, a signal generating circuit 8 is excited by an oscillator 10 as an exciting device to output an AE wave having a different frequency and waveform all that time when the tool is abnormal. A diagnostic device 9 is provided to the arithmetic part 2 and the AE wave generated by the device 8 is received through a machine table 3, sensor 1, and lead wire 11 and outputted when there is not reception. The moment the device 9 judges that no signal is received, that is outputted to the controller 6 of the machine through a signal line 12. Consequently, the abnormality of the device itself is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a tool breakage detection device that detects when an abnormality occurs in a cutting tool used in a machining center or the like and notifies the processing machine Δ of the abnormality. In particular, the present invention relates to a tool breakage detection device with a self-diagnosis function for detecting an abnormality in a sensor and lead wire that utilizes the principle of acoustic erosion (hereinafter referred to as "AEJ").

(Prior Art) In the technology related to tool breakage detection devices using kE, various companies have devised various signal processing methods to improve tool abnormality detection ability. However, A.E.
At present, the self-diagnosis function for abnormalities up to each lead wire, including damage and disconnection within the sensor, is difficult and completely undeveloped. Since the tool breakage detection device does not generate a signal indicating that the tool is abnormal, you may think that the tool is normal, but if the sensor or lead wire breaks or the connector becomes loose, the abnormality cannot be detected, creating a pile of defective products or causing damage to the machine. (Problem to be Solved by the Invention) The present invention solves problems in the tool abnormality detection sensor and in the lead wire.
It is an object of the present invention to provide a tool breakage detection device having a self-diagnosis function capable of detecting an abnormality such as a disconnection of a wire or a looseness of a connector in a sensor and its signal input path.

(Means for Solving the Problems) Therefore, in the present invention, when there is an abnormality in the sensor and its signal acquisition path, that is, in the case of a failure or disconnection of the sensor,
It is possible to use the absence of a signal to recognize that a problem has occurred with the tool breakage detection device, and to notify an external device that there is an abnormality in itself, making it possible to use it as a tool abnormality detection sensor. A tool breakage detection device including a calculation unit that processes a signal from the sensor, which is adjacent to the sensor, is detectable by the sensor, and generates a signal with a signal waveform and frequency different from a signal waveform and frequency generated when the tool abnormality occurs. a diagnostic device that is attached to the arithmetic unit and that receives the signal from the signal generator via the sensor and outputs that when there is no reception. This is a tool breakage detection device with a self-diagnosis function.

(Function and Effect) In this configuration, normally the signal generator is always connected, but when an abnormality occurs in the sensor and its signal acquisition path,
In other words, if there is a failure or disconnection of the sensor or lead wire,
The diagnostic device can perform self-diagnosis by outputting that the above-mentioned signal is not received through the sensor, that is, by outputting an abnormality (controller abnormality).

(Example) Next, an example of the present invention will be described with reference to the drawings. Conventionally, as shown in Fig. 3, if a tool such as a drill (4) malfunctions while machining a workpiece (5), the tool such as the machine table (3) or tool chuck A tool abnormality detection sensor (1) installed adjacent to the
) receives the AFi signal, and the lead wire (11) connects the arithmetic unit (
2), and the tool abnormality determined by the calculation unit (2) is transmitted from the signal line (7) to the machine control device (6) to stop the machine, energize an alarm buzzer, etc.

In contrast, in the present invention, as shown in the embodiment of FIG.
When the drill (4) becomes abnormal, such as broken, the next AE wave is transmitted from the workpiece (5) to the tool abnormality detection sensor (1) via the machine table (3). The sensor (1) captures the waveform and sends it to a calculation unit () to determine if there is an abnormality in the feeding tool. If the tool is abnormal, this is notified to the machine control device (6) via the signal line (7).

Up to this point, things are the same as before, but in addition to this, the oscillator αO, which is an excitation device, functions as an oscillator that generates a waveform with a frequency different from that calculated when the tool breaks.At this frequency, the signal generator ( 8) is excited and output as an Affi wave having the above waveform. The signal generator (8) is the sensor (1) K
Although provided adjacent to each other, the sensor (1) may be in contact with the sensor (1). Further, a diagnostic device receives the AK wave of the above waveform generated by the signal generator (8) via the mechanical table (3), the sensor (1) and the lead wire αη, and further outputs it when there is no reception. (9) is installed alongside the calculation section (2). That is, A of the waveform detected by the sensor (1)
The E wave is constantly input to the diagnostic device (9) via the lead wire α〃, and the n1 diagnostic device (9) judges that there is such reception, but if it is determined that this reception is no longer present, the signal line ( 6), this fact is output to the machine control device (6) as an abnormality in the tool breakage detection device itself. Therefore, if the sensor (1) is malfunctioning or the sensor (1)
The sensor (1) and its signal acquisition path are checked for abnormalities such as disconnection of the wiring or looseness of the connector between the sensor (1) and the calculation section (2).

As can be seen from the partial electrical circuit diagram of Fig. 1 shown in Fig. 2, the AE wave for tool damage detection is normally applied to the calculation section (2).
) /< 7 The waveform passing through the pass filter αη is smoothed. If the level of this smoothed signal exceeds a preset level, the arithmetic processing unit α determines that there is a tool abnormality.
It's a barrel. If you are doing operations like this,
The oscillator αO generates a signal such as 600 KFIZ, 700 KH2, etc. outside the range of the above-mentioned filter, and excites the piezoelectric element (8) which is a signal generator. The diagnostic equipment (9) includes a band pass filter 4 that passes through 600 KHz and 700 KH2, and checks whether the waveform passing through this filter is always above a certain level.The oscillator αO If the frequency generated by the piezoelectric element (8) becomes higher, it becomes difficult for the signal to be transmitted from the piezoelectric element (8) to the piezoelectric element (1) which is a sensor, so it is preferable that both piezoelectric elements (11 (8) are installed very close to each other).

(Field of application of the invention) So-called flexible manufacturing systems (FMS) and factory automation (
In an unmanned factory using FA), the controller that controls the machines needs to have a self-diagnosis function. By applying the tool breakage detection device with self-diagnosis function according to the present invention, it has become possible to create a stable and reliable machining cell as a whole factory system.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a tool breakage detection device with a self-diagnosis function based on the present invention (an embodiment), Figure 2 is a block diagram showing a partial electric circuit of Figure 1, and Figure 3 is a block diagram of a conventional product. A block diagram of a certain tool breakage detection device is shown.

Claims (1)

[Claims] A tool breakage detection device including a tool abnormality detection sensor and a calculation unit that processes a signal from the sensor, which is adjacent to the sensor and is detectable by the sensor, and has a signal waveform/frequency that occurs when the tool abnormality occurs. a signal generator that generates different signals; and a diagnostic device that is attached to the calculation section and that receives the different signals from the signal generator via the sensor and outputs the signals when there is no reception. A tool breakage detection device with a self-diagnosis function, comprising: