JPH01138437A - Scratch testing machine - Google Patents

Abstract

PURPOSE:To accurately measure the depth of a scratch in real time by providing an acoustic wave detection sensor which measures the contacting between an indentator and a sample and the depth of the scratch. CONSTITUTION:The device consists of a pendulum 8 which vibrates freely while its one end is fixed on a rotary shaft and the indentator 7 for scratching is fixed to the other end, an angle detector 9 which measures the angle of rotation of the indentator 7, a test-piece 1, and a driver 3 which moves a sample base 2 where the test-piece 1 is fixed perpendicularly, a displacement gauge 4 which determines the depth of the scratch of the indentator 7 from the surface of the test-piece 1 by detecting the movement quantity of the test base 2, and the acoustic wave detection sensor 10. Then, the indentator 7 contacts the sample in the process wherein the indentator 7 scratches the surface of the sample, and the sample 1 continues to radiate an elastic wave up to the end of the scratching process. The acoustic wave detection sensor 10 measures the continuance of this elastic wave to accurately measure the length and depth of the scratch made by the indentator in the surface of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a scratch tester that scratches the surface of a solid with an indenter and measures the scratch deformation strength of the material.

(Conventional technology) Current ultra-precision machining technology has achieved a finished surface roughness of 10 nm and a shape accuracy of about 1 pm or more, and is actually used in the production lines of many optical devices and magnetic disk substrates. Incorporates ultra-precision processing. This kind of ultra-precision machining requires high precision of bearings and crossheads used in machine tools, management of tools and materials, high precision control of the machining environment such as anti-vibration and dust prevention, measurement of minute displacements and drive technology. has been supported by the establishment of However, the machining accuracy is said to be exceeding the limits of normal measurement technology, and innovation in measurement technology is said to be an essential condition for improving machining accuracy in the future. on the one hand,
There is also a demand for a 1 iniL precision machining process that maintains the current machining accuracy and has higher productivity than the current one. For example, in the processing process for magnetic disk substrates mentioned above, since the A1 alloy that is the substrate material is a soft and ductile material, burrs are likely to occur during cutting, and the rate of good products that meet standard values is extremely low. It's staying. Furthermore, it has been pointed out that since the A1 alloy tends to adhere to the cutting edge of the tool, the tool life is shortened and it takes a lot of time to replace the tool. In order to overcome these challenges, it is necessary to optimize machining conditions and quantitatively understand the factors that affect machining phenomena. It has been pointed out that there is a need to study

Based on the above-mentioned current situation, several strain testing machines and testing methods have been proposed as a means of obtaining information regarding the deformation state that the material surface undergoes. For example, JP-A-6
The scratch tester described in Publication No. 2-245131 has the following features: (1) Unlike conventional low-speed scratch testers, the scratch deformation resistance of the material surface can be measured in a speed range comparable to the cutting speed.b1. (2) Compared to conventional testing machines, it is possible to measure the deformation resistance of extremely thin surface layers of microns or less. It is characterized by the following two points, and provides an effective means for quantifying factors that influence the ultra-precision processing phenomenon described above.

(Problems to be Solved by the Invention) However, the above-mentioned scratch testing machine has a problem in that the scratch depth can be accurately measured in real time during an experiment. In other words, although the scratching tester is equipped with a drive mechanism and a displacement measurement unit that precisely control the scratching depth, it is difficult to detect and measure the contact between the indenter and the sample surface and the depth at which the indenter scratches the surface. There is no means provided to do so.

(Means for Solving the Problems) The present invention comprises a freely oscillating pendulum having one end fixed to a rotating shaft and a scratching indenter fixed to the other end, and an angle detector for measuring the rotation angle of the indenter. , a driver that vertically moves the test piece located below the pendulum and the sample stand on which the test piece is fixed, and a driver that moves the test piece and the pendulum by detecting the amount of movement of the sample stand. A displacement meter that determines the scratch depth with an indenter fixed at the end, and a sound wave detection sensor that measures the scratch depth by detecting the sound waves generated during the scratching process when the indenter contacts the sample surface. This is a scratch tester characterized by being equipped with.

That is, the present invention can reduce the energy expended when an indenter fixed to the tip of a pendulum vibrating at a speed of several 100 cm/sec or less scratches the sample surface, which is a feature of the scratch tester shown in the prior art section. In addition to an angle detector that measures the contact between the indenter and the sample, a driver that changes the scratch depth between the indenter and the sample surface by raising and lowering the sample, and a displacement meter that measures the amount of drive of the driver. and a scratch tester equipped with a sonic sensor to measure scratch depth.

(Function) The acoustic wave detection sensor (hereinafter referred to as AE sensor) has a function of detecting elastic waves generated when a substance is deformed or destroyed. It is well known that almost all materials exhibit the so-called acoustic emission phenomenon, in which they emit elastic waves under high strain rate conditions, ie when subjected to rapid deformation. In this tester as well, the indenter comes into contact with the sample during the process of scratching the sample surface, and the sample continues to emit elastic waves until the scratching process is completed. By measuring the duration of this elastic wave using the aforementioned AE sensor, the length and depth of the scratch made by the indenter on the sample surface can be precisely measured.

Moreover, the deformation resistance is measured as follows.

Using the lifting angle α of a pendulum with an indenter fixed to its tip, the swinging angle p of the pendulum after the indenter scratches the surface, and the volume ■ of the arc-shaped scratch groove formed on the surface, the scratch deformation resistance R can be calculated as R= mgr(cosp-cosα)/V (1
) was defined. Here, m is the equivalent inertial mass of the entire pendulum system acting on the indenter, g is the gravitational acceleration, and r is the radius of the pendulum. The angles α and p can be precisely measured using an angle detector.

(Embodiment) FIG. 1 is a diagram showing an embodiment of the present invention. A sample 1 is fixed on a sample stage 2 by a vacuum chuck.

Sample stage 2 is set to X by a micrometer.

XYz that can be manually moved in 3 directions of Y and Z with lpm accuracy
The table is capable of fine adjustment driving in two directions (arrow directions) using a piezoelectric actuator 3 used as a driver. Light 5 from an optical fiber 4 (trade name Photonic Probe) that measures the amount of drive of the sample stage 2 is reflected by a mirror 6 fixed on the sample stage 2 by a vacuum chuck, returns to the optical fiber 4, and the reflected light is The amount of displacement is measured by the strength of the The distance between the optical fiber 4 and the mirror 6 can be set to a predetermined value by controlling the voltage applied to the piezoelectric actuator 3. That is, the scratch depth was controlled by interlocking the voltage signal applied to the piezoelectric actuator 3 and the displacement signal from the optical fiber displacement meter. The indenter 7 is fixed to the tip of a pendulum 8, and the other end of the pendulum 8 is attached to the rotating shaft of an optical rotary encoder 9 used as an angle detector.

The optical rotary encoder 9 detects the lifting angle α of the pendulum and the swinging angle p of the pendulum after being hit.

The pendulum 8 is kept stationary in the vertical direction, and the sample stage is manually raised in two directions. Thereafter, the voltage applied to the piezoelectric actuator 3 is increased to bring the sample 1 and the indenter 7 into contact.

The AE sensor 10 detects the elastic waves generated during this contact, and determines the contact position.

The AE sensor 10 is fixed to the surface of the sample 1 or to the sample stage 2 with an adhesive. If it is desired to measure the contact position with high sensitivity, it is desirable to fix the AE sensor 10 to the sample surface. After determining the contact position, the pendulum is lifted to a predetermined lifting angle α, the piezoelectricity applied to the piezoelectric actuator 3 is further increased, and the scratching depth is set. The pendulum is allowed to fall freely and a scratch test is performed. The elastic waves generated during this scratching process are measured by the AE sensor 10,
Measures the actual scratch depth in real time. The swing-up angle p after scratching is also measured by an optical rotary encoder 79.

FIG. 2 is a block diagram showing one embodiment of the present invention. The control signal from the personal computer 11 linked to the displacement signal from the photonic probe 4 is digitalized.
Analog converter 12, constant voltage power supply 13, voltage amplifier 14
The amount of movement of the sample stage 2 was controlled by applying it to the piezoelectric actuator 3 via the . Further, the signal from the optical rotary encoder 9 is data-processed via a digital counter 15 and a personal computer 11, and is outputted to a display 16 or a printer 17 as a change in the angle of the pendulum during the hit test. Note that the displacement signal from the photonic probe 4 is sent to the photonic sensor 18,
The signal is input to the personal computer 11 through an analog/digital converter 19. The elastic waves generated during the hitting process are detected by the AE sensor 10, and the preamplifier 20. It is input to the personal computer 11 via the AE analyzer 21 and the digital oscilloscope 22. The personal computer 11 calculates the depth and length of the stroke from the duration of the elastic wave. Finally, the scratch deformation resistance is measured based on equation (1) from the energy loss demand determined by the signal from the optical rotary encoder 9 and the scratch volume calculated from the scratch depth.

Next, the performance of the hit tester of the present invention will be explained using measurement examples.

(Measurement example) Using the scratch testing machine shown in Figures 1 and 2, scratch deformation resistance was measured for a sample in which a 10 mm square glass substrate was coated with a Cr film with a thickness of lpm by magnetron sputtering. Shina. Measurement conditions were pendulum radius near cm, pendulum lifting angle: 90°, indenter: apex angle 120°.
Diamond conical indenter in °, inertial mass acting on the indenter:
12g, set maximum depth of scratching groove: 0.4pm, scratching speed: 93cm/see. Lifting angle α;
90°, swing angle 13=87.2°. Also,
The actual maximum scratch depth measured by the AE sensor is 0.
．． It was 49pm. The reason why the set value and measured value of the scratch depth differ is because the sample surface was deformed during the initial contact position setting operation 6, and because the scratch test was performed on a surface that had not been deformed after the contact position was confirmed. This is caused by moving the sample. After the test, the depth of the scratch groove was actually measured using a surface roughness meter and found to be 0.49.
3 pm, which agrees with the value measured by the AE sensor within two significant figures. Also, the scratch deformation resistance of the Cr film calculated from the measurement data is 6.5 x 11012
It was er/am3.

(Effects of the Invention) As described above, the scratching tester according to the present invention enables real-time, high-precision measurement of scratching depth, so that scratching depths of 0. 1p
It was found that the scratch deformation resistance of the surface layer at m level can be measured quickly and with high accuracy. In addition, it is necessary to manually move the sample stage in the XY force direction after confirming the contact position or when making multiple measurements on the same sample, but even at this time, the actual contact position between the sample and the indenter cannot be detected. Another advantage is that it can detect the depth of scratches.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing an example of the structure and block diagram of an embodiment of the scratch tester of the present invention. In the drawings, 1 is a sample, 2 is a sample stage, 3 is a piezoelectric actuator, 4 is a photonic probe, 5 is a light, 6 is a mirror, 7 is an indenter, 8 is a pendulum, 9 is an optical encoder, and 10 is an AE
Sensor, 11 is a personal computer, 12 is a digital/analog converter, 13 is a constant voltage power supply, 14 is a voltage amplifier, 15 is a digital counter, 16 is a display, 17 is a printer, 18 is a photonic sensor, 19
is an analog/digital converter, 20 is a preamplifier, 21
22 is an AE analyzer, and 22 is a digital oscilloscope.

Claims (1)

[Claims] A freely vibrating pendulum with one end fixed to a rotating shaft and a scratching indenter fixed to the other end, an angle detector for measuring the rotation angle of the indenter, a test piece located below the pendulum, and the test piece. A driver that vertically moves a specimen stage with a fixed specimen, and a displacement device that determines the scratch depth between the surface of the specimen and an indenter fixed to the other end of the pendulum by detecting the amount of movement of the specimen stage. A scratch testing machine characterized by being equipped with a sonic wave detection sensor that detects sound waves generated during the process of scratching the surface of a sample with an indenter.