JPH01199758A - Ultrasonic machine - Google Patents

Abstract

PURPOSE:To keep vibration amplitude of a tool constant for maintaining machining precision in good even in a case of change in temperature of a piezoelectric transducer during machining by providing a control unit for the purpose of controlling an ultrasonic generator so as to obtain a preset value in vibration amplitude of a tool detected with a noncontact type displacement sensor. CONSTITUTION:A piezoelectric transducer 30 is made to vibrate with high frequency current from an ultrasonic generator 41, and the vibration on the piezoelectric transducer 30 is enlarged with a horn 31 for giving the vibration to a tool 32 (glinding stone) to perform ultrasonic machining on a work W at a hole Wa with the tool 32. On this occasion, a noncontact type displacement sensor is provided on a position facing to the tool in the direction of vibration on the tool 32. The ultrasonic generator 41 is controlled by a generator control unit 42 so as to obtain a preset vibration amplitude of the tool 32 an actual vibration amplitude of the tool 32 detected by the sensor 40. The vibration amplitude of the tool 32 can be always made constant thereby, and the machining precision can be kept in constant.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ultrasonic processing machine that performs processing by vibrating a tool.

<Prior Art> Such an ultrasonic processing machine vibrates a vibrator using a high frequency current from an ultrasonic oscillator, and amplifies the vibration of the vibrator with a horn to give vibration to a tool.

<Problems to be Solved by the Invention> The vibration characteristics of the vibrator change due to temperature changes and the like during use, and the amplitude width of the tool changes, resulting in a problem of poor processing accuracy.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems, and a non-contact displacement sensor is provided at a position corresponding to the tool in the vibration direction of the tool. The apparatus is equipped with an oscillator control device that controls the ultrasonic oscillator so that the actual amplitude width of the tool obtained by the method becomes the preset amplitude width of the tool.

<Operation> During machining, the tool and the non-contact sensor are made to correspond, and the oscillator control device controls the ultrasonic oscillator so that the actual amplitude width of the tool matches the preset amplitude width.

<Example> Hereinafter, an example of the present invention will be described based on FIG. 1. Labor 0
is a bed, and a guide stand 11 is installed in this bed 10. A table 12 is guided by a guide stand 11 so as to be horizontally movable, and this table 12 is driven by a servo motor 13 attached to the guide stand 11 via a ball screw mechanism of a circuit. A column 14 is erected on the bed 10 behind the table 12, and a guide surface 15 is formed in the vertical direction on the front surface of the column 14. A processing head 20 is guided by the guide surface 15 so as to be movable in the vertical direction, and this processing head 20 is driven by a servo motor 21 attached to the column 14 via a ball screw mechanism of a circuit. A main shaft 22 is rotatably supported on the processing head 20 about a vertical axis, and the main shaft 22 is rotationally driven by a main shaft motor 23 attached to the processing head 20.

At the tip of the main shaft 22 is a vibrator 3 that generates vibrations in the vertical direction.
0 is attached to the vibrator 30, and a horn 31 for magnifying the vibration of the vibrator 30 is attached to the vibrator 30. horn 31
A cylindrical grindstone (tool) 32 is attached to the tip. A non-contact displacement sensor 40 is installed on the table 12, and this non-contact displacement sensor 40 is installed on the table 12.
By the movement of , the position corresponding to the grindstone 32 is determined in the vibration direction of the grindstone 32 . Said vibrator 3
0 is connected to an ultrasonic oscillator 41 that generates high-frequency electricity, and an oscillator control device 42 that controls the ultrasonic oscillator 41 is connected to this ultrasonic oscillator 41. A waveform shaping circuit 43 that shapes the waveform signal from the noncontact displacement sensor 40 is connected to the non-contact displacement sensor 40, and an amplitude measurement circuit 44 that measures the amplitude width of the waveform signal is connected to the waveform shaping circuit 43. It is connected. The oscillator control device 42
mainly consists of a gate circuit 50, an amplitude setting circuit 51, and a comparison circuit 5.
2, and the opening/closing control of the gate circuit 50 is controlled by a numerical control device 53. The amplitude setting circuit 51 stores the optimum amplitude width of the grinding wheel 32, and the comparison circuit 52 compares the amplitude width stored in the amplitude setting circuit 51 with the actual amplitude width from the amplitude measuring circuit 44. It is something to do. The numerical control device 53 controls the drive of the servo motor 13.21 and the spindle motor 23. A workpiece W having a plurality of holes Wa is installed on the table 12.

Next, the operation will be explained based on the flowchart shown in FIG. When a machining command is issued from the numerical control device 53, the servo motor 13 is driven, and the first hole Wa is formed on the grindstone 32.
The table 12 moves to the corresponding position. Next, the main shaft 22 is rotated by the main shaft motor 23 and a high frequency current is applied to the vibrator 30, and the processing head 20 is lowered by the servo motor 21. At this time, the grindstone 32 vibrates up and down while rotating, and the hole Wa is ultrasonically processed.

When the machining is completed, the machining head 20 is raised, and unless a machining completion command and an amplitude measurement command are issued, the table 12 is moved to a position corresponding to the next hole Wa on the grindstone 32, and the same machining as described above is performed. If a machining completion command is issued, table 1
2 moves to the original position, and the rotation of the main shaft 32 and the vertical vibration of the grindstone 32 are stopped.

When an amplitude measurement command is issued, the table 12 moves to a position where the displacement sensor 40 corresponds to the grindstone 32, and the processing head 20 descends to a position where the grindstone 32 approaches the displacement sensor 40. When the grindstone 32 is vibrated while the rotation of the main shaft 12 is stopped, a waveform signal is obtained from the displacement sensor 40. This waveform signal is shaped by a waveform shaping circuit 43, and the amplitude width of the shaped waveform signal is measured by an amplitude measuring circuit 44. The gate circuit 50 is opened only during amplitude measurement by the numerical controller 53, and the measured amplitude width signal is sent to the comparison circuit 5.
2, and the amplitude measurement circuit 51 is input to the comparison circuit 52.
The amplitude width signal stored in is input. If the measured amplitude width is smaller than the stored amplitude width, the ultrasonic oscillator 41 is controlled to increase the amplitude of the high-frequency current, and conversely, if the measured amplitude width is larger than the stored amplitude width, the high-frequency current is increased. Ultrasonic oscillator 4 so that the amplitude of the current is small
1 is controlled. When the measured amplitude width becomes equal to the stored amplitude width, the gate circuit 50 is closed and the processing head 20
is raised and the table 2 is moved to the position corresponding to the next hole Wa on the grindstone.Subsequently, the same ultrasonic processing as described above is performed. At this time, the vibration of the grindstone 32 has an optimal amplitude width, so that good machining can be performed.

In the above embodiment, the displacement sensor 40 is provided on the table 12, but an arm may be attached to the column 14 so as to be able to rotate in a horizontal plane, and the displacement sensor may be attached to the tip of the arm.

, <Effects of the Invention> As described above, the present invention provides a non-contact displacement sensor at a position corresponding to the tool in the vibration direction of the tool, and the actual amplitude width of the tool obtained by the non-contact displacement sensor is The structure is equipped with an oscillator control device that controls the ultrasonic oscillator so that the amplitude width of the tool is set in advance, so even if the temperature of the vibrator changes during machining, the amplitude width of the tool can be kept constant. , the effect of keeping the machining volume constant is obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall view of an ultrasonic processing machine, and FIG. 2 is a flowchart showing processing and measurement operations. 30... Vibrator, 31... Horn, 32... Grindstone (tool), 40... Non-contact displacement sensor, 41...
Ultrasonic oscillator, 42... Oscillator control device, 43...
Waveform shaping circuit, 44...amplitude measurement circuit.

Claims (1)

[Claims] (1) In an ultrasonic processing machine in which a vibrator is vibrated by high-frequency current from an ultrasonic oscillator, and the vibration of this vibrator is magnified by a horn to give vibration to the tool,
A non-contact displacement sensor is provided at a position corresponding to the tool in the vibration direction of the tool, and the vibration is adjusted so that the actual amplitude width of the tool obtained by the non-contact displacement sensor becomes a preset amplitude width of the tool. An ultrasonic processing machine characterized by being provided with an oscillator control device that controls a sonic oscillator.