JPH05177512A - During-cutting surface roughness judging method - Google Patents

Abstract

PURPOSE:To accurately carry out surface roughness judgment during cutting for providing a judging method suitable as a machining abnormality detecting system during unmanned operation by obliquely applying ultrasonic waves to a cutting part through a liquid medium, and also by detecting the reflected waves from the cutting part. CONSTITUTION:A work to be cut 1 is cut by a cutting tool 2 that has been fitted to a tool holder 3. In this case, a chamber in which cutting oil 6 has been filled is formed on the work 1 on the opposite side of the cutting tool 2, and herein a probe holder 7 for holding a ultrasonic probe 4 is arranged. To this ultrasonic probe 4, a ultrasonic transmitter 9 and a receiver 10, and the others are connected. The ultrasonic waves from the ultrasonic probe 4 are obliquely applied to the cutting part through cutting oil 6, and also the reflected waves from the cutting part are detected by the ultrasonic probe 4. Further, the detected signals are compared with a voltage-roughness conversion table by means of a computer 14 for judging the surface roughness. On the other hand, in accordance with the result of the surface-roughness judgment, a machine tool is controlledly driven by a control unit 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface roughness determination method for monitoring the cutting surface accuracy required for unmanned operation of machine tools.

[0002]

2. Description of the Related Art When operating a machine tool unattended, there is a demand for a system for immediately issuing an alarm when a predetermined cutting surface roughness is impaired in order to minimize defective products. For this reason, research has been conducted in various fields, and as examples, an air leak method, a high response stylus method, various optical methods (Industrial Tool Encyclopedia (published by the Industrial Research Board)), etc. have been proposed. However, the so-called air leak method and high-response stylus method are difficult to use for those that rotate at normal cutting speed, and the optical method is characteristically used under cutting environment such as cutting oil, smoke, etc. Insufficient reliability and very few practical examples.

[0003]

Among the above-mentioned conventional methods, the most promising optical roughness measuring method is not widely used because the reliability of the cutting oil adhered to the cutting surface as described above. Based on the significant lack of. As a result of pursuing a method that is not affected by cutting oil, the present inventors considered a method of positively utilizing cutting oil.

An object of the present invention is to provide a new method for determining surface roughness during cutting, which has developed a method for monitoring the roughness of the cutting surface with high accuracy in a cutting environment.

[0005]

According to the present invention for achieving the above object, an ultrasonic wave is obliquely incident on a cutting portion through a liquid medium during cutting, and then a reflected wave from the surface of the cutting portion is detected. Then, the detected value is obtained.

[0006]

[Function] Creates a room in which the cutting surface is filled with cutting oil, etc., radiates ultrasonic waves to the cutting section through this cutting oil, detects the surface irregular reflection components that have returned, and cuts surface roughness at the detection level. The degree is judged.

[0007]

EXAMPLES Examples of the method of the present invention will now be described with reference to FIGS. FIG. 1 is a block diagram for an example method. In the figure, reference numeral 1 is a work piece, which is cut by a cutting tool 2 attached to a tool holder 3. On the other hand, on the side opposite to the side where the cutting tool 2 is located, the cutting oil 6
Is provided with a probe holder 7 that forms a room filled with the ultrasonic probe 4 and holds the ultrasonic probe 4. In this case, ultrasonic wave 5
The ultrasonic probe 4 so that it enters the cutting part at an angle.
Emitted by. Also, 8 turns on the supply of cutting oil 6 /
It is a valve for turning off.

Reference numeral 9 is an ultrasonic transmitter connected to the ultrasonic probe 4, and 10 is an ultrasonic receiver similarly connected to the ultrasonic probe 4. The gate circuit 11 connected to the ultrasonic receiver 10 detects only the reflected wave from the surface of the cutting portion. 12 is an A / D converter, 13 is an interface for computer connection, 14 is a computer,
Reference numeral 15 is a control unit of the machine tool.

According to the structure shown in FIG. 1, when the pulse voltage generated by the ultrasonic transmitter 9 is applied to the probe 4, ultrasonic waves are radiated into the cutting oil 6 and reach the work surface. .. Here, most of the light is specularly reflected, but a very small amount of it becomes a weak diffuse reflection component due to the surface condition and returns to the direction of the probe. This returning ultrasonic wave is detected by the probe 4 and amplified by the receiver 10. Next, the gate circuit 11 extracts only the effective signal (the received signal also includes the noise echo reflected inside the probe holder 7, but from the propagation time,
Only the signal reflected from the surface is extracted), and the voltage is A /
The digital signal is converted by the D converter 12 and input to the computer 14 via the interface 13. The computer determines the surface roughness by associating the voltage of the input signal with a voltage-roughness conversion table registered in advance. If it is an abnormal value, a machining stop command is output to the control device 15 of the machine tool.

2 and 3 show the surface roughness of the work material and the result of the reflection level measurement. That is, FIG. 2 shows a diameter of 1 shown in (1).
When turning a 10 mm stainless steel round bar with a lathe, change the tool in the middle of the process and process (2) (3) in Fig. 2.
As shown in (4), the surface roughness is changed in three stages. When this processing is performed, frequency 12
Using the probe 4 with MHz, transducer diameter 6.3 mm and focal length 25 mm, the surface reflected wave was detected under the conditions of incident angle 40 ° and amplification degree 48 dB, and the analog output was output to the pen writing recorder. .. FIG. 3 shows the result.

The echo level is about 1.5 V at the A portion where the surface roughness is about 6.5 s, and about 0.7 V at the B portion where the surface roughness is 2.6 s, and the C is about 1.6 s. In the area, the echo level is clearly changed to about 0.3 V, and the change in surface roughness can be reliably detected.

The relationship between the surface roughness and the surface echo level varies depending on the incident angle, but when the top-finished surface is monitored, the change amount is small at an incident angle of 25 ° or less, which is 30 ° to
About 45 ° is suitable. Further, although water-soluble cutting fluid was used as the cutting oil in this example, water containing a rust preventive agent may be used in a processing machine that does not use the cutting fluid.

[0013]

As described above, according to the present invention, since highly reliable roughness measurement can be performed even in a cutting environment, it is useful as a machining abnormality detection system during unmanned operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a method of the present invention.

FIG. 2 is an explanatory diagram of a work piece used for verification of an embodiment of the method of the present invention.

FIG. 3 is a waveform chart showing measurement results of the work piece shown in FIG.

[Explanation of symbols]

 1 Workpiece 4 Ultrasonic probe 6 Cutting oil 7 Probe holder 9 Ultrasonic transmitter 10 Ultrasonic receiver 11 Gate circuit 12 A / D converter 13 Interface 14 Computer 15 Machine tool control device

Claims (1)

[Claims] 1. Surface roughness determination during cutting, in which ultrasonic waves are obliquely incident on a cutting portion through a liquid medium during cutting, and then a reflected wave from the surface of the cutting portion is detected to obtain a detected value. Method.