JP2008116349A - Microcompression testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microcompression testing machine capable of sequentially and automatically performing a compression test with respect to the granular sample scattered on a lower pressure plate at random and reducing the load of an operator. <P>SOLUTION: The microcompression testing machine dispenses with the participation of an operator from the searching of the sample to the execution of a test by providing an imaging means 20 for imaging the sample scattered over a lower pressure plate 13 through an object lens 15, an image processing means 32 for calculating the position data of the sample in a visual field by image processing using the imaging output of the imaging means, a discrimination means 33 for identifying whether a compression test is possible alone with respect to the sample the position data of which are calculated and a control means 34 for automatically driving a slide stage 18 and an X-Y stage 16 even the sample identified to be tested alone to move the sample to the area just under an intender 14 and driving a load mechanism to perform a compression test using the intender 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a micro-compression tester for evaluating the compressive strength and the like of a granular sample having a particle size of about several μm to several hundred μm.

  For example, a testing machine called a micro-compression testing machine is known as a testing machine for evaluating the compression characteristics of particles (substantially spherical) having a particle size of about several μm to several hundred μm, such as metal or ceramic powder. . In this type of conventional micro-compression tester, an indenter (upper platen) having a flat bottom surface is provided above the lower platen (sample stage), and the indenter is driven by a load mechanism on the lower platen. The structure which presses the mounted granular sample is taken, and the lower platen can be moved along the horizontal plane by the XY stage, and can be moved in the vertical direction by the Z stage. In addition, an objective lens of an optical observation device (microscope) is arranged on the side of the position where the indenter is arranged, and the lower platen, together with the XY stage and Z stage, is optically observed directly below the indenter by the slide stage. It can move between directly under the objective lens of the apparatus (see, for example, Patent Document 1).

  In the test, the optical observation device recognizes the granular sample randomly scattered on the platen so that a compressive load can be applied to one granular sample by the indenter, and moves it to the planned test position, that is, directly below the indenter. To do. This operation is performed by the operator manually operating the XY stage and the slide stage.

Here, when automating the above test operation, the XY stage and the Z stage are motorized, and a sample is set on the lower platen in advance in a grid-like accurate position, and the x and y directions are set. A method of driving each stage by setting a pitch is employed.
Japanese Patent Application Laid-Open No. 5-93683

  By the way, in the above-described conventional micro-compression tester, it is not possible to automatically perform sequential tests on granular samples randomly scattered on the lower platen. Such an operation for the test requires a great deal of labor for the operator. That is, for example, when a granular sample is difficult to disperse, the sample interval becomes narrow, and it is necessary to search for one granular sample that is sufficiently separated from the other in relation to the size of the indenter. However, it takes effort to find an appropriate sample. Also, although dispersion is simple, it takes a lot of effort to find the sample if the granular sample has been dispersed very sparsely. In either case, because the sample is small, it cannot be confirmed with a microscope with a large field of view and a low magnification, and it is necessary to search for the sample using a high magnification microscope with a narrow field of view.

  Furthermore, since the automatic test cannot be performed, it is necessary to wait in the vicinity of the testing machine for the waiting time during the test, and there is a problem that the time loss is large.

  The present invention has been made in view of such circumstances, and can sequentially and automatically perform compression tests on granular samples randomly scattered on the lower platen, thereby reducing the burden on the operator. The challenge is to provide a micro-compression tester that can be used.

  In order to solve the above problems, a micro compression tester according to the present invention includes a lower platen on which a granular sample is placed, an XY stage that holds the lower platen and moves along a horizontal plane, and the lower platen is moved vertically. A Z stage that moves along the direction, an indenter that is provided above the lower platen, has a flat lower surface, and drives the indenter along the vertical direction to apply a compressive load to the granular sample on the lower platen. A load mechanism to be applied; an imaging means for a sample including an objective lens provided at a predetermined distance in the horizontal direction from the position where the indenter is disposed; and the lower platen together with the XY stage below the indenter. And a lower stage of the objective lens, the XY stage, the Z stage, and the slide stage are each driven by an electric stage. The imaging output of the plurality of granular samples randomly placed on the lower platen is captured by the imaging means, and the granular sample pattern on the lower platen is input using a granular sample pattern input in advance. Image processing means for obtaining position information, position information for the granular sample by the image processing means, and determination means for determining whether or not the granular sample can be subjected to a compression test alone, based on pre-input conditions; When it is determined by the determination means that a single test is possible, the slide stage and the XY stage are driven to position the granular sample directly under the indenter, and then the Z stage is driven. Having a control means for driving the load mechanism and performing a compression test after setting the distance between the granular particles and the indenter to a prescribed pre-test start distance. It characterized me (claim 1).

  Here, in the present invention, the field of view of the imaging means can be sequentially changed, and the operations by the image processing means, the discrimination means and the control means can be repeatedly executed (claim 2).

  The present invention takes a granular sample randomly scattered on the lower platen, obtains positional information of the granular sample in the field of view by image processing using a granular sample pattern inputted in advance, From the set conditions, it is determined whether or not the granular sample can be subjected to a compression test alone. If so, it is automatically positioned directly under the indenter by driving the electric XY stage, and the electric Z An attempt is made to solve the problem by driving the load mechanism and performing a compression test after setting the vertical distance between the indenter and the granular sample to a specified distance by driving the stage.

  That is, in the present invention, after taking a granular sample randomly scattered on the lower platen, obtaining the position information of the granular sample in the field of view, the condition that the granular particles are input in advance, for example, the indenter Whether or not the granular sample is in a state where it can be subjected to a compression test on its own based on whether or not there are other granular particles in the area determined by the size of the lower surface and the size of the granular sample If it is determined that it is possible to test alone, the electric slide stage, XY stage and Z stage are automatically driven to perform a compression test, and the operator is involved after the test starts. In addition, a micro-compression tester that can automatically perform from a search for a granular sample to a test is realized.

  As in the invention according to claim 2, by sequentially changing the field of view of the imaging means and repeating the same operation, a compression test of a larger number of granular samples can be performed automatically in succession.

  According to the present invention, even when the granular sample is randomly scattered on the lower platen, the granular sample is automatically searched for and the test is performed, so that the operator's workload can be reduced. Further, if the configuration is such that the search and test of the granular sample are continuously performed as in the invention according to claim 2, the operator can perform other work during the long-time test on a large number of samples. It becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of an embodiment of the present invention, and is a diagram illustrating a front view representing a mechanical configuration and a block diagram representing a system configuration.

  The testing machine main body 1 has a structure in which a column 12 is erected on one end of the bed 11 (the back side in the figure), a lower platen 13 is arranged on the bed 11 side, and an indenter 14 and an objective lens 15 are arranged on the column 12 side. ing.

  The lower platen 13 is fixed by a gripping tool 17 on an XY stage 16 that moves in two directions (x direction and y direction) orthogonal to each other on a horizontal plane by driving motors 16a and 16b. The stage 16 is placed on a slide stage 18 that moves by a specified amount in the x direction by driving a motor (not shown). These components are mounted on the Z stage 19 that moves in the vertical direction (z direction) by driving the motor 19a.

  The column 12 protrudes above the lower platen 13, and an indenter 14 and an objective lens 15 are disposed at the protruding portion. The indenter 14 is finely displaced vertically downward by a known load mechanism capable of applying a minute load using an electromagnetic force generator, for example, and can apply a compression load to the granular sample on the lower platen 13. .

The objective lens 15 is arranged at a position spaced apart from the arrangement position of the indenter 14 by a certain distance in the x direction, and the slide stage 18 moves the lower platen 13 between them. By the movement of the slide stage 18 by a specified amount, the portion located directly below the objective lens 15 on the lower platen 13 is configured to come directly below the indenter 14.
Incident light to the objective lens 15 is guided to the imaging surface of the CCD camera 20 via another optical element such as a prism, and an image of the granular sample on the lower platen 13 positioned immediately below the objective lens 15 through the objective lens 15. Can be taken under the set magnification.

  The output of the CCD camera 20 is guided to the image processing unit 32 via the image capturing circuit 31, and the image processing unit 32 uses the granular sample pattern and the upper surface pattern of the lower platen 13 which are input in advance. If a granular sample exists in the field of view of the CCD camera 20, the position information (x, y coordinate information) is obtained. Further, the image processing unit 32 has an autofocus function, and drives the Z stage 19 via a control unit 34 described later so that the outline of the granular sample becomes clear.

  Position information from the image processing unit 32 is sent to the determination unit 33, which determines whether or not the granular sample can be subjected to a compression test alone, as will be described later.

  Based on the determination result of the determination unit 33, when there is a granular sample that can be subjected to a compression test alone in the field of view of the CCD camera 20, the XY stage 16 is driven via the motor control circuit 35. Then, the sample is positioned so that the corresponding sample is located immediately below the objective lens 15, and the slide stage 19 is driven through the motor control circuit 35 to move the lower platen 13 below the indenter 14. As a result, the corresponding granular sample is positioned immediately below the indenter 14, and in this state, the load mechanism is driven to perform a compression test.

  The motor control circuit 35 is placed under the control of the control unit 34, and an operation unit 36 for inputting conditions and the like to be described later or giving various commands to the control unit 34, and the CCD camera 20. A display 37 for displaying an image of the sample photographed by the above, test results, and the like, and a memory 38 for storing input information from the operation unit 36, image data from the CCD camera 20, and the like are connected. The control unit 34, the image processing unit 32, and the determination unit 33 are actually configured by a computer and its peripheral devices, and execute various operations in accordance with programs installed in the computer. In FIG. 1, for the sake of explanation, a block diagram corresponding to functions executed by the program is shown.

FIG. 2 is a flowchart showing the above-described operation, and the operation of the present invention will be described in detail with reference to FIG.
First, a granular sample is scattered on the lower platen 13 and necessary information is input. This information includes the size of the indenter 14, the photographing magnification of the CCD camera 20 including the optical system such as the objective lens 15, the appearance of the granular sample to be tested (size, shape, etc.), and the appearance of the lower platen 13 (brightness). Etc.), the minimum distance between samples, the sample search range, and the like.

  When the above input is finished and a command to start the test is given, the following operation is automatically executed thereafter. First, after the XY stage 16 is positioned so that a specified corner on the surface of the lower platen 13 is in the field of view of the CCD camera 20, image data is captured by performing autofocus. The granular sample is searched for using the sample information input earlier and the pattern information of the lower platen 13. At that time, for the reason to be described later, only a sample existing in a preset range, specifically, a range within the minimum distance between the samples from the outer edge of the visual field of the CCD camera 20 is set as a candidate.

  If there is a sample in the field of view of the CCD camera 20, it is determined whether or not there is another sample or dust within a preset minimum sample distance around the sample. This minimum inter-sample distance is determined mainly based on the size of the indenter 14 (the size of the flat surface on the lower surface). That is, as shown in the example of the image by the CCD camera 20 in FIG. 3, if no other sample exists within the minimum distance between the samples indicated by the radius C around the sample W1, it is determined that the compression test can be performed alone However, since the sample W2 has another sample W3 within the radius C centered on the sample W2, the sample W3 may be simultaneously pressurized when being pressed by the indenter 14, and therefore, it is determined that the sample W2 cannot be tested alone. To do. The sample search range is based on the minimum inter-sample distance. For the sample W4 near the outer edge of the visual field, the minimum inter-sample distance is applied to the outer edge of the visual field. It is not a candidate for discrimination. This is the reason why only the samples within the range inward by the minimum inter-sample distance from the outer edge of the visual field are candidates as described above.

  When it is determined that there is a sample that can be subjected to a compression test alone in the field of view, the XY stage 16 is moved so that the sample is positioned at the center of the field of view of the CCD camera 20, and autofocus is performed again. Go and read the sample size (length and width). This sample size is necessary for calculating the strength of the sample, and the reading is performed by the image processing unit 32 and stored in the memory 38. Next, the Z stage 19 is lowered by a distance that is half the average value of the sample size. This focuses on the top of the sample. When the sample is moved directly below the indenter 14 with the focus on the top of the sample in this way, the objective lens 15 is previously set so that the positional relationship between the two in the z direction can be immediately subjected to a compression test. The relative position of the indenter 14 in the z direction is set. In this state, the slide stage 18 is driven to move the sample directly under the indenter, and then the load mechanism is driven to perform a compression test.

  After execution of the test, the slide stage 18 is driven to move the lower platen 13 to the initial position below the objective lens 15. When the next test is continued, the XY stage 16 is driven to shift the visual field of the CCD camera 20 and the same operation as described above is repeated. The movement of the visual field of the CCD camera 20 is inside the preset sample search range, and the sample search range is covered by individually moving in the x-direction movement amount and the y-direction. As illustrated in FIG. 4, (x-direction size of field of view) − (minimum distance between samples) × 2 in the x-direction, and (y-direction size of field of view) − (minimum sample) in the y-direction. Distance) × 2. Accordingly, there is a possibility that the sample indicated by W5 in FIG. 4 that is not a candidate because it is at the outer edge of the visual field in the previous visual field becomes a candidate in the current search.

  When the entire search range is searched, the test is terminated. Even when there is no particle that can be tested alone in the field of view, the field of view of the CCD camera 20 is moved in the same manner as described above, and the same operation is performed.

  According to the above-described embodiment of the present invention, the operator first disperses the granular sample on the lower platen 13, sets and inputs necessary conditions, and the test machine automatically executes all the rest. Compared to the case where a test is performed by searching for individual granular particles with a microscope as in the conventional testing machine of this type, the labor is remarkably reduced. Further, if a method of reading the sample size by image processing is adopted, there is no individual difference as in the case where the operator reads the size, and the reliability or reproducibility of the test is improved.

  Depending on the material of the sample, etc., there is a sample that easily adheres to the indenter after the compression test. In such a case, if a function for automatically removing the sample attached to the indenter is added, a wider range can be obtained. An automatic test can be performed on the sample.

It is a block diagram of embodiment of this invention, and is the figure which writes and shows together the front view showing a mechanical structure, and the block diagram showing a system structure. It is a flowchart which shows the procedure of the automatic test operation | movement in embodiment of this invention. It is explanatory drawing of the method of discriminate | determining whether a compression test is possible independently in embodiment of this invention. It is explanatory drawing of the method of moving the visual field of a CCD camera in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test machine body 11 Bed 12 Column 13 Lower platen 14 Indenter 15 Objective lens 16 XY stage 17 Grasp 18 Slide stage 19 Z stage 20 CCD camera 31 Image data acquisition circuit 32 Image processing part 33 Discriminating part 34 Control part 35 Motor Control circuit 36 Operation unit 37 Display 38 Memory

Claims (2)

A lower platen on which a granular sample is placed, an XY stage that holds the lower platen and moves along a horizontal plane, a Z stage that moves the lower platen along a vertical direction, and a position above the lower platen An indenter having a flat lower surface, a load mechanism for driving the indenter along the vertical direction to apply a compressive load to the granular sample on the lower platen, and a predetermined position in the horizontal direction with respect to the placement position of the indenter. A sample imaging means including an objective lens provided at a position separated by a distance, and a micro stage provided with a slide stage that moves the lower platen together with the XY stage between the lower side of the indenter and the lower side of the objective lens. In the compression tester,
The XY stage, the Z stage, and the slide stage are each constituted by an electric stage, and the imaging output by the imaging means of a plurality of granular samples randomly placed on the lower platen is captured and input in advance. Based on the image processing means for determining the position information of the granular sample on the lower platen using the pattern of the granular sample, and the compression test of the granular sample alone based on the obtained position information and pre-input conditions A discriminating means for discriminating whether or not it is possible, and when the discriminating means discriminates that the granular sample can be tested alone, the slide stage and the XY stage are driven to After positioning directly under the indenter, the Z stage is driven to determine the distance between the granular particles and the indenter before starting the prescribed test. After the release, micro-compression testing machine, characterized in that it comprises a control means for compression testing by driving the loading mechanism.   2. The micro-compression tester according to claim 1, wherein the field of view of the imaging unit is sequentially changed, and the operations of the image processing unit, the discrimination unit, and the control unit are repeatedly executed.

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