JPS61241048A - Supervisory method for ultrasonic machining - Google Patents

Abstract

PURPOSE:To enable machining accuracy to be improved, by detecting a load condition and an ultrasonic vibrative system condition when ultrasonic machining is performed through a change of vibrator impedance and a driving frequency during the actual operation. CONSTITUTION:In order to detect abnormality in a load condition and an ultrasonic vibration system condition, the method respectively detects a driving frequency, driving voltage and a driving current from a driving frequency measuring device F, driving current measuring device I and a driving voltage measuring device V mounted to an ultrasonic oscillator 1. Further an impedance measuring device Z detects vibrator impedance on the basis of these driving current and driving voltage. The driving frequency of the ultrasonic oscillator 1 and the vibrator impedance detected in the above are fed to an arithmetic circuit 5. The supervisor method, comparing these values with an experimentally obtained preset value, decides a condition in a load level and a condition of abnormality and change in an ultrasonic vibration system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to ultrasonic machining, and more particularly to a method for monitoring machining conditions during ultrasonic machining.

(Prior art) When machining a workpiece using ultrasonic waves, it is necessary to monitor the machining state by some method, and in the past, the output or output phase of the ultrasonic oscillator was measured using an ammeter connected to the ultrasonic oscillator. A method was used to detect the amount.

(Problems to be Solved by the Invention) However, since this conventional method merely detects the output, it has the following drawbacks.

That is, this method cannot be said to be true monitoring of the machining state because it detects machining conditions that include abnormalities and changes in the ultrasonic vibration system itself.

In addition, it is not possible to distinguish whether the detected changes are based on factors such as pressurizing force, feeding force, processing fluid, etc., which are the processing conditions of the processing machine itself, or whether they are based on factors on the ultrasonic vibration system side. Ta.

In this case, the conventional monitoring method is very rough and is not suitable as a method for high quality control of automatic processing machines.

(Means for Solving the Problems) This invention aims to accurately detect load conditions and abnormalities in the ultrasonic vibration system by changes in the vibrator impedance and drive tube wave number during actual operation during ultrasonic machining. It is.

(Example) Hereinafter, the present invention will be described in detail based on the drawings. Figure 1 is a block diagram of an ultrasonic processing machine.
2 is an ultrasonic oscillator, 2 is an ultrasonic vibration system, and this ultrasonic vibration system 2 is composed of a vibrator, a booster horn, a horn, and a tool. 3 in the figure represents the workpiece, and Hiroshi represents the main body of the processing machine. This main body of the processing machine consists of applications, construction, processing fluid supply mechanism, etc., and the ultrasonic vibration system 2 and the workpiece 3. It is designed to be retained. Further, depending on the case, some machines have a mechanism for rotating the ultrasonic vibration system 2 and the workpiece 3.

In the present invention, an ultrasonic oscillator l is used to detect load conditions and abnormalities in the ultrasonic vibration system.

Drive frequency measuring instrument F1 drive wJ current measuring instrument installed on
Drive frequency from drive voltage measurement 6V, drive '11! + out,
The drive current is outputted respectively, and this drive current, drive a
The impedance measuring device 2 detects the vibrator impedance based on the 'h pressure.

The driving frequency of the ultrasonic oscillator detected in this way,
Oscillator impedance is an arithmetic circuit! and is compared with experimentally obtained set values described below to determine the magnitude of the load state, abnormality of the ultrasonic vibration system, and state of change.

Note that the relationship between the drive frequency, transducer impedance, and ultrasonic vibration system changes depending on the workpiece, processing conditions, ultrasonic conditions, temperature, etc., so conduct processing experiments in advance and determine the setting values accordingly. Of course you should.

Figure 2 is a graph showing the experimentally confirmed relationship between drive frequency, vibrator impedance, and overload/underload. As the frequency increases, the sensor impedance decreases. On the other hand, when the load becomes small for some reason, the driving frequency becomes low and the vibrator impedance becomes large.

Therefore, by looking at the state of change in the driving frequency and the vibrator impedance, it is possible to know whether there is an underload or an overload.

In addition, abnormal conditions in the ultrasonic vibration system itself, such as cracks in tools and loosening of screw connections, appear as a decrease in both the driving frequency and the vibrator impedance, as shown in Figure 3, and can be clearly distinguished from abnormalities in the load. be done.

In this way, the arithmetic circuit j determines whether there is a load abnormality or an abnormality in the ultrasonic vibration system based on changes in the drive frequency and transducer impedance, and based on this, a control signal is issued to stop the device or modify the motion. [Effect of the Invention] As described above, in this invention, it is possible to accurately know the load condition and abnormality of the ultrasonic vibration system from the frequency of the drive output output from the ultrasonic oscillator and the transducer impedance. ,
It can be used for all types of ultrasonic processing, such as welding machines, cutting machines, free abrasive processing machines, cutting blade processing machines, plastic processing machines, etc. that use ultrasonic waves, and is outstanding in improving processing accuracy. have an effect.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the ultrasonic processing machine used in this invention, Figure 2 is a graph showing the relationship between overload, underload, drive frequency, and transducer impedance. Figure 3 is the ultrasonic vibration system. 3 is a graph showing the relationship between drive frequency and vibrator impedance. l... Ultrasonic oscillator, 2... Ultrasonic vibration system, 3...
・Workpiece, ≠...Processing machine body, F...Drive frequency measuring device, Machining...Drive current measuring device, ■...Drive voltage measuring device

Claims (1)

[Claims] A method for monitoring ultrasonic machining, characterized in that the load state and the state of an ultrasonic vibration system during ultrasonic machining are detected by changes in transducer impedance and drive frequency during actual operation.