JPH0499946A - Method and apparatus for measuring cutting ability of grinder wheel - Google Patents

Abstract

PURPOSE:To measure the cutting ability by detecting acoustic emission (AE) signals generated in a work cutting time and indicating these to a chart, and by comparing this with a known chart. CONSTITUTION:A nonmagnetic ceramics substrate 1 is fixed in a work table 3 through a glass plate 2 and the substrate 1 is cut with a grindstone 4. An AE signal detecting sensor 10 is set up on the table 3, and its signals are converted into electric signals by an electric circuit 11 and indicated to a chart of an indicator 12. The cutting quality of the grindstone can be momentarily and continuously judged by being compared with various chart shapes previously prepared to change cutting conditions.

Description

[Detailed Description of the Invention] The present invention measures the sharpness of a grindstone (blade) for cutting a workpiece, selects the blade, selects cutting conditions (blade rotation speed, cutting speed, etc.), and determines the cutting quality of the blade. The present invention relates to a method and device for measuring the sharpness of a grindstone, which can be used to determine the lifespan of a grindstone or the timing of dressing. In particular, the present invention provides a method and apparatus that can be suitably employed for monitoring the sharpness of a blade when cutting a non-magnetic ceramic substrate of a laminated magnetic head with a blade.

[Izumiri Niuraura: For example, in recent years, digital audio, VTR, HDD
A multilayer magnetic head consisting of a non-magnetic substrate, a magnetic alloy thin film and a non-magnetic substrate, which has excellent characteristics in the high frequency range and is capable of high-density recording, has high output and low noise, and is being put into practical use.

Currently, non-magnetic ceramic substrates are used as non-magnetic substrates for such laminated magnetic heads for various reasons including durability.

Since such non-magnetic ceramic substrates are very hard and brittle, such substrates are generally cut with a blade having diamond abrasive grains.

However, since the non-magnetic ceramic substrate is very hard, the sharpness of the blade deteriorates significantly as the blade is used.

If cutting is carried out with a blade whose sharpness has deteriorated, the cutting resistance during processing will be extremely large, which will not only reduce work efficiency but also cause chipping at the corners of the fragile workpiece surface, i.e. non-magnetic ceramics. Occurrence of chipping or peeling of the substrate is experienced. These chippings not only become a source of dust, but also cause problems such as destroying the gap in the manufactured magnetic head.

The present inventors conducted research experiments to solve such problems, and found that when cutting a workpiece with a blade, AE (Acoustic Emission) is generated, and the AE multiplied signal, It fluctuates as the sharpness of the blade decreases, and therefore the A
Detected by an E-fold signal sensor, the detection signal from the sensor is displayed on a display device, and the shape of the chart displayed on the display device is compared with a known chart obtained by pre-measurement. It was discovered that the sharpness of a whetstone can be judged by this method.

The present invention has been made based on this new knowledge.

Therefore, an object of the present invention is to
Detects the double signal, monitors the AE double signal fluctuation, judges the sharpness of the grindstone, selects the blade, selects cutting conditions (blade rotation speed, cutting speed, etc.), determines blade life or dressing timing, etc. It is an object of the present invention to provide a method and device for measuring the sharpness of a grindstone, which can be used for.

The above objects are achieved by the method and device for measuring the sharpness of a grindstone according to the present invention. To summarize, the present invention detects with a sensor the AE multiplied signal generated when cutting a workpiece with a grindstone,
The sharpness of the grindstone is determined by displaying the detection signal from the sensor on a display device and comparing the shape of the chart displayed on the display device with a known chart obtained by measurement in advance. This is a method for measuring the sharpness of a whetstone.

Such a method includes: a table for fixing a work; a sensor attached to the surface of the table for detecting an AE multiplied signal generated when cutting the work with a grindstone;
Suitable in a grindstone sharpness measuring device characterized by having an electric circuit that converts a detection signal from the sensor into an electric signal, and a display device that displays the signal from the electric circuit so that it can be visually observed. Implemented.

Next, the method and device for measuring the sharpness of a grindstone according to the present invention will be explained in more detail with reference to the drawings.

FIG. 1 illustrates the process of cutting a nonmagnetic ceramic substrate during manufacturing of a multilayer magnetic head. A non-magnetic ceramic substrate 1 is adhesively fixed to a work table 3 via a glass plate 2. The nonmagnetic ceramic substrate 1 is cut with a grindstone, that is, a blade 4.

According to the present invention, the work table 3 is provided with the AE signal detection sensor 10. According to the research of the present inventors, the AE multiplied signal in this example is usually 10 KHz to 150 KHz.
Since the frequency band is spread over the Hz, a piezoelectric element is suitable as the sensor 10, and for example, a product such as rF-15AGJ manufactured by Sanko Control Co., Ltd. can be suitably used.

The detection signal from the sensor 10 is transmitted through a preamplifier, a filter,
It is converted into an electric signal by an electric circuit 11 equipped with a main amplifier, arithmetic unit, etc., and transmitted to a display device 12, and then displayed on a CRT.
It is displayed on a display or printed out on recording paper using a data recorder so that it can be visually observed by the operator.

Figures 2(A) to 2(S) show the results obtained using the apparatus of the present invention when a non-magnetic ceramic substrate 1 with a thickness T of 097 mm and a length of 26 mm was fully cut with the blade 4. Show chart.

In this example, the blade 4 used is rsD2000J manufactured by Reed Co., Ltd., and the cutting conditions are as follows: The number of revolutions of the blade 4 is 20,000 rpm, and the cutting speed is 0.
5mm/sec, depth of cut for full cut is 0.7
It was 2 mm.

In addition, although F-15AG was used as the sensor in this example, resonance characteristics were clearly observed in the band below 20 KHz, and the frequency band for measuring the cutting state was 1.
5KHz±20% is considered suitable.

FIG. 2(a) is a chart for the first time, that is, the first line cutting, and FIG. 2(b) to (g) are the charts for the third.
This is a chart when cutting the 4.6.7.8.9 line. The vertical axis shows the AE signal level (maximum amplitude), and the horizontal axis shows time.

As can be understood by observing Figure 2 (a) to (g),
When the blade 4 comes into contact with the workpiece 1, which is a non-magnetic ceramic substrate in this embodiment, and starts cutting, A suddenly increases.
E level increases. Therefore, by observing this "rise", it is possible to detect that the blade 4 has contacted the workpiece 1. The AE multiplied signal changes as the cutting progresses.

According to this embodiment, except for when cutting the first line, the shape of the chart when cutting the third line to the ninth line is similar in that it has two peaks, the first peak and the second peak. I can see that it is happening.

The reason why the chart shape when cutting the first line shows a different chart shape than when cutting the other lines is that the blade 4 is new and has just been dressed, and has extremely good cutting performance (therefore, the cutting resistance is small and This is because the cutting can be performed in a substantially constant state from the start of cutting to the end of cutting.

Furthermore, the first peak seen in the chart when cutting from the third line to the ninth line is due to a temporary increase in the AE multiplication signal due to the cutting resistance when the blade 4 starts cutting. It is thought that the peak is caused by the signal increasing by AE times due to the fluctuation in cutting resistance that occurs when the blade 4 is pulled out from the workpiece 1.

When the present inventors observed the cut surface of the workpiece cut in this way, it was found that chipping, which was said to have a maximum size of 26 μm, had occurred on the cut surface due to the ninth line cutting. This is a permissible limit in magnetic head manufacturing. Therefore, in this embodiment, the shape of the chart at the time of cutting the 9th line shown in FIG. indicates the life of the blade.

Furthermore, according to this embodiment, the peak of the amplitude distribution in the chart shape when cutting the 1st to 8th lines is below level 6.8, whereas the peak of the amplitude distribution in the chart shape when cutting the 9th line is The peak has changed to a level of 7.0 or higher, and furthermore, the frequency band level when cutting the 9th line, that is, the AE level, has increased by about 1.2 compared to the AE level when cutting the 1st line. I found out that there is.

Furthermore, the shapes of the charts shown in Figures 2 (a) to (g) are as follows:
Experiments have shown that if the cutting conditions are constant, a constant value can always be obtained.

As described above, according to the present invention, various charts are prepared in advance with different cutting conditions, and it is determined in advance what chart shape the blade sharpness is in. During actual cutting work, the sharpness of the grindstone can be judged immediately and continuously by comparing the shape of the chart displayed on the display device with a known chart obtained by measuring in advance. , blade dressing timing, blade life, blade selection, and cutting condition selection.

Note that the comparison with known charts can not only be performed directly by a person but also automatically using a personal computer.

As described above, according to the present invention, the sharpness of the grindstone can be determined by detecting the AE multiplied signal generated when cutting the workpiece and monitoring the fluctuation of the AE multiplied signal. It has the advantage of being able to select blades, select cutting conditions (blade rotation speed, cutting speed, etc.), and determine blade life or dressing timing.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a grindstone sharpness measuring device according to the present invention. FIGS. 2(A) to 2(G) are charts printed out on the display device. 1: Work 2 Glass plate 3 Table 4 Blade 11: Electric circuit 12: Display device procedure manual (spontaneous) November 5, 1990

Claims (1)

[Claims] 1) A sensor detects an AE signal generated when cutting a workpiece with a grindstone, the detection signal from the sensor is displayed on a display device, and a chart is displayed on the display device. A method for measuring the sharpness of a whetstone, characterized in that the sharpness of the whetstone is determined by comparing the shape of the whetstone with a known chart obtained by measuring in advance. 2) A table for fixing the workpiece, a sensor attached to the surface of the table to detect the AE signal generated when cutting the workpiece with a grindstone, and converting the detection signal from the sensor into an electrical signal. What is claimed is: 1. A grindstone sharpness measuring device comprising: an electric circuit for detecting a signal from the electric circuit; and a display device for displaying a signal from the electric circuit in a visually observable manner.