JPS60114446A - Numerical controller - Google Patents

Abstract

PURPOSE:To detect abnormal working quickly and reliably by automatically modifying the setting level of comparing circuit for deciding abnormality of working through numerical controller. CONSTITUTION:Mechanical vibration produced through working is converted into an electrical signal SA and amplified then provided to a filter 3 to produce a signal SB removed of disturbance which is amplified and provided to a smoothing circuit 5 to produce a signal SC which is converted into a digital signal SD and fed to comparators 7, 8. While a signal SE is provided from numerical controller 13 to setting level circuit 9 to set the level T1 for breakdown of tool with correspondence to the working pulse. A signal SF is fed from the circuit 9 to the circuit 7 to set the level T1. Since the setting level TM is set in the circuit 8 by the signal SG, upon occurrence of abnormal working such as breakdown of tool during boring work, the signal SD will exceed over the setting level T1 to latch the abnormality detection signal SH in the circuit 11 thus produce an abnormality signal SI in the circuit 13 and to produce an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a numerical control device having a function of automatically detecting processing abnormalities.

[Technical background of the invention and its problems]

BACKGROUND ART Recently, machining abnormality detectors have been used to detect, for example, abnormalities in mechanical vibration and load current, and to automatically detect machining abnormalities such as tool breakage and entanglement of chips. In this case, setting values corresponding to the machining mode are manually set in advance, and these setting values are used to clearly distinguish whether the machining is in a normal state or an abnormal state.

By the way, so-called numerical control (Numerical C
(ontrol; NC) A machine tool is equipped with a plurality of types of tools having different sizes and shapes, and a desired tool is used in a timely manner based on commands from a command tape. In other words, in NC machine tools, the vibration mode used to detect machining abnormalities depends on the type of tool.

Also features that frequently change depending on the material of the workpiece.

ing. Therefore, when the machining abnormality detector is installed in the NC1 machine tool, there arises a problem that the set values must be manually reset one after another every time the machining mode changes. Moreover, determining the set value in this case is extremely difficult. This has been one of the reasons for discouraging the application of machining abnormality detectors to NC machine tools. Therefore, most conventional NC machine tools do not have a function to automatically detect machining abnormalities, and detection of machining abnormalities depends mainly on the operator's five senses. This was a major obstacle to complete self-sales of NC machine tools.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances.

It is an object of the present invention to provide a numerical control device that can automatically set a set value for detecting machining abnormalities according to the machining mode, and can detect machining abnormalities quickly and reliably.

[Summary of the invention]

A numerical control circuit automatically changes the set value of a comparator circuit for detecting machining abnormalities to distinguish abnormality from normality.

[Embodiments of the invention]

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an electric circuit diagram of a numerical control device according to one embodiment. The detector (1) is, for example, an acceleration pickup and is directly attached to the main body of the NC machine tool.

This detector (1) is connected to a filter (3) via an amplifier (2). This filter (3) is for passing only vibrations in a specific frequency band, for example, 200 to 1000 Hz, in order to remove disturbances. The output side of this filter (3) is connected to the 1
For example, it is connected to the input side of a smoothing circuit (5) such as an effective value (RM8) circuit. The output side of this smoothing circuit (5) is connected to the input side of an analog-to-digital (A/D> converter (6). The output side of this A/D converter (6) is connected to the first These first and second comparison circuits (7), (8) are connected to the input side of the comparison circuit (power and second comparison circuit (8)), respectively.
(8) A first set value circuit (9) and a second set value circuit a that output a digital signal indicating the set value set in
〔It is connected to the. Furthermore, the output sides of these first and second comparison circuits m, L8) are connected to a first holding circuit ←υ and a second holding circuit 04, such as a latch circuit, respectively.
It is connected to the. These first and second holding circuits (1
1), '(13 is connected to a numerical control circuit (19) consisting of, for example, a microconverter. This numerical control circuit U has a memory function and arithmetic function, and controls the NC machine tool body. The servo mechanism to be driven, a detection device for detecting the position of the workpiece and tool, and an external input device for inputting NC command information to the numerical control circuit are electrically connected. )teeth,
The first set value circuit (9) is connected to the first set value circuit (9), and a control signal is output from the first set value circuit (9), which indicates an appropriate set value depending on the processing mode. Also.

The system is designed to detect abnormalities throughout the entire period, including when machining is stopped, and it is possible to manually set desired setting values.

Next, the operation of the numerical control device having the above configuration will be described. First, by using the M function of the command tape in the storage device of the numerical control circuit Q3i, for each type of tool or machining pass,
First comparison circuit (set value Tl + T* to be input to force
+... to be memorized. These setting values T8゜T! ,・
... is used to detect machining abnormalities such as tool damage and entangled chips, and is determined experimentally in advance. On the other hand, for the second set value circuit (101), a set value TM is manually set. This is to detect even if the first comparison circuit (7) is in a reset state and is not monitored in the comparison circuit (8) of the first comparison circuit (8). Mechanical vibration is converted into an electrical signal SA by a detector (1), and this electrical signal SA is amplified by an amplifier (2) and outputted to a filter (3) K. From this filter (3), A signal SB in a specific frequency band from which disturbances have been removed is output.This signal 8B is amplified by an amplifier (4) and output to a smoothing circuit (5). 8B is.

The effective value (RM8) processed and smoothed signal SC is A/
D converter (6) outputs K (see Figure 2). This A/
In the D converter (6), the signal SC is analog-to-digital converted, and the digital signal SD is outputted to the first and second comparison circuits (7) and (8). On the other hand, from the numerical control circuit (13), a signal SE is sent to the first set value so that the set value T1 corresponding to the machining pass (for example, drilling) is set in the first set value circuit (9). It is output to the circuit (9). Therefore, from this first set value circuit (9),
Signal 8F is output to the first comparator circuit (7), and this first
The comparison circuit (force) is set to a set value T□. On the other hand, the second comparison circuit (8) is set to a set value TM by the signal SG output from the second set value circuit QI. There is.

Thus, when a machining abnormality such as tool breakage occurs during drilling, the signal 8D, which is the A/D conversion value of the signal SC, exceeds the set value TI, as shown in FIG. As a result, the abnormality detection signal SH indicating the logical value "1" is once latched in the first holding circuit 0υ. Next.

An abnormality detection signal SI is output from this first holding circuit (10) to the numerical control circuit 0 east, and the numerical control circuit (+3) to which this signal 8I is input starts the alarm device and activates the servo device. A control signal to temporarily stop is output.Furthermore, after the first machining pass, for the second and subsequent machining passes, the numerical control circuit (13) sets the set value T corresponding to each machining pass. !+ Tsl...
is sequentially set to the first comparison circuit (force), and machining abnormality detection is performed in the same manner as described above (see Figure 2). If the tool collides with the workpiece for some reason between then, the first holding circuit 01) is in the reset state,
First comparison circuit (abnormality cannot be detected by force. However,
As shown in FIG. 2, the signal 8D is connected to the second comparison circuit (8).
As a result, the abnormality detection signal 8H' indicating the logical value "1" is latched into the second holding circuit (I).Then, this second holding circuit (+2 to numerical control An abnormality detection signal 8I is output to the circuit (+3), and the numerical control device performs the same emergency operation as described above.

In this way, the numerical control device of this embodiment can automatically change the set value of the first comparison circuit (7) that detects machining abnormalities according to the machining mode. It can be easily incorporated into NC machine tools. As a result, the reliability of processing is improved, the burden on one worker is reduced, and processing automation can be further completed. moreover.

Since the second comparison circuit (8) also detects abnormalities not caused by direct machining during the entire NC machining period, the reliability of machining can be further improved.

Note that the second comparison circuit (8) and the accompanying circuit in the above embodiment are omitted, and between each machining pass, that is, during a machining pause, the first comparison circuit (automatically sets the set value TM to the force) Furthermore, the first and second
The set value circuits (9) and (II) may be omitted, and the required set value may be set directly from the numerical control circuit (13) to the first comparator circuit (force).Furthermore, the first and Second
Holding circuit aυ, (13 may be omitted and output may be made directly from the first and second comparison circuits (7) to the numerical control circuit 0. Furthermore, the A/D converter (6) may be omitted. The first and second comparison circuits (power, (8) and smoothing circuit (5)
) so that the output value from the path is directly input, and the output value from the path is outputted as an analog signal. Furthermore, the filter (3) and the smoothing circuit (5) may not be used depending on the processing mode. Further, as the detector (1), an ultrasonic sensor, a sonic sensor, a load current detector, a load power detector, a processing temperature detector, etc. may be used.

〔Effect of the invention〕

Since the present invention is configured to automatically change the setting values of the comparison circuit that detects machining abnormalities according to the machining mode, the target of abnormality detection is expanded and can be easily incorporated into normal NC machine tools. . As a result, the reliability of processing is improved, the burden on one worker is reduced, and processing automation can be further completed.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit system diagram of a numerical control device according to an embodiment of the present invention, and FIG. 2 is a timing chart for explaining abnormality detection. (1): Detector, (7): (First) comparison circuit. (13: (numerical) control circuit.

Claims (1)

[Claims] A detector that detects changes in physical quantities that occur in the detection target and converts them into electrical signals, and compares the electrical signal output from this detector with a preset setting value and detects the change in the detection target based on the comparison result. A numerical control device comprising: a comparison circuit that detects an abnormal state of the object; and a control circuit that automatically changes a set value set by the comparison circuit according to the state of the object to be detected.