Test device and test piece testing method

Abstract

To derive the deflective strength of a test piece with high accuracy.SOLUTION: Provided is a test device for carrying out destruction test of a test piece, the test device comprising: a support table having a pair of support parts for supporting the underside of the test piece; an indenter for pressing from above the test piece supported with the support table; a load measurer for measuring the load acting upon the support table or the indenter; a movement unit for moving the indenter closer to or away from the test piece supported with the support table; and a controller. The controller includes: a load storage part for storing the load applied to the support table or the indenter measured by the load measurer when the test piece is tested for destruction by causing the indenter to press the test piece supported with the support table from above; and a distance storage part for calculating, and storing, the distance in vertical direction between the upper end of the support table and the lower end of the indenter on the basis of the height of the indenter when a load greater than or equal to a threshold is detected by the load measurer due to the fact that the indenter comes into contact with the test piece supported with the support table during execution of the test.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a testing apparatus for measuring the strength of a test piece such as a device chip, and a method for testing the test piece. [Background technology]

[0002] In the device chip manufacturing process, devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed in multiple regions on the front surface of a wafer, which are partitioned by multiple intersecting dividing lines (streets).The wafer is then thinned and divided along the dividing lines to obtain multiple device chips, each equipped with a device.The device chips are then installed in electronic devices such as mobile terminals and personal computers.

[0003] The manufactured device chips are required to have sufficient mechanical strength. Therefore, destructive testing is performed using the device chips as test specimens. Generally, the three-point bending test specified in SEMI standard G86-0303 is widely performed. A testing device has been proposed that uses this method to destroy the chip and calculate its flexural strength (see Patent Document 1).

[0004] The testing device has a support table that supports the test specimen at two supports and an indenter that presses the test specimen supported by the support table from above between the two supports to break it. The flexural strength of the test specimen is calculated from the value of the load applied to the indenter when the test specimen is broken by pressing it. In addition to this load value, parameters used to calculate the flexural strength include the distance between the two supports and the thickness of the test specimen. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-190449 Summary of the Invention [Problem to be solved by the invention]

[0006] To accurately calculate the flexural strength of a test piece, it is necessary to measure the thickness of each test piece before it breaks. However, if an operator touches a test piece while measuring its thickness, the test piece may become dirty or its properties may change slightly. In addition, the task of measuring the thickness of all the test pieces takes a huge amount of time and effort.

[0007] One possible method is to incorporate a camera or other device into the testing equipment and use this device to detect the thickness of each test piece. However, incorporating such a device not only increases the cost of the testing equipment, but also can cause adverse effects on the test due to the heat and vibrations generated by the operation of the device. Therefore, it is possible to calculate the flexural strength of a test piece using the specified thickness of the test piece rather than the actual measured value of the thickness of each test piece.

[0008] However, because the actual thickness of each test piece varies from the specifications, the value of the flexural strength calculated based on the specified thickness does not reflect this variation. In other words, this method does not allow for accurate calculation of the flexural strength of each test piece. For example, if an inaccurate flexural strength is used when selecting wafer processing conditions, the optimal processing conditions may not be selected.

[0009] Furthermore, when destructive testing is performed on multiple test pieces one after another using a testing device, fine debris such as broken pieces may fly off and adhere to the support base or indenter. If destructive testing is performed on test pieces with debris attached to the support base or indenter, the calculated flexural strength value will be even less accurate.

[0010] Therefore, an object of the present invention is to provide a testing device and a testing method that can derive the flexural strength of a test piece with high accuracy. [Means for solving the problem]

[0011] According to one aspect of the present invention, there is provided a testing apparatus for conducting a destructive test on a plate-shaped test piece, the testing apparatus comprising: a support base having a pair of support parts for supporting the underside of the test piece; an indenter for pressing the test piece supported by the support base from above; a load measuring instrument for measuring the load applied to the support base or the indenter; a movement unit for moving the indenter toward and away from the test piece supported by the support base; and a controller, wherein the controller further comprises: a load memory section for storing the load applied to the support base or the indenter measured by the load measuring instrument when a test is conducted in which the indenter, which is moved by the movement unit, presses the test piece supported by the support base from above to destroy the test piece; and a distance memory section for calculating the vertical distance between the upper end of the support base and the lower end of the indenter based on the height of the indenter when a load equal to or greater than a threshold is detected by the load measuring instrument as the indenter comes into contact with the test piece supported by the support base during the test, and for storing the distance.

[0012] Preferably, the controller further includes a judgment unit that judges whether or not there is an abnormality in the test that destroys the test piece based on the distance stored in the distance memory unit, and a judgment condition memory unit that stores judgment conditions that are referenced when the judgment unit judges whether or not there is an abnormality in the test.

[0013] Furthermore, preferably, the judgment unit calculates the average value of the distances stored in the distance memory unit when the test is conducted on multiple test pieces, the judgment condition memory unit stores a setting method for determining an acceptable range of the distance based on the average value as the judgment condition, and the judgment unit determines the acceptable range using the average value and the setting method stored in the judgment condition memory unit, and judges whether or not there is an abnormality in the test based on whether or not the distance stored in the distance memory unit for the test to be judged is within the acceptable range.

[0014] Alternatively, preferably, the judgment condition memory unit stores an acceptable range of the distance as the judgment condition, and the judgment unit judges whether or not there is an abnormality in the test based on whether or not the distance stored in the distance memory unit in the test to be judged is within the acceptable range.

[0015] Alternatively, preferably, the controller calculates the bending strength of the test piece by referring to the load stored in the load memory unit and the distance stored in the distance memory unit.

[0016] According to another aspect of the present invention, there is provided a test method for conducting a destructive test of a test piece using a testing device including a support base having a pair of support parts that support the underside of a plate-shaped test piece, an indenter that presses the test piece supported by the support base from above, a load measuring device that measures the load applied to the support base or the indenter, and a movement unit that moves the indenter toward and away from the test piece supported by the support base, the test method comprising: a loading step for loading the test piece on the support base; a test piece breaking step that, after the loading step, carries out a test in which the moving unit brings the indenter closer to the support base and the indenter presses the test piece with the indenter to break it, while measuring the load applied to the support base or the indenter with the load measuring device; and a recording step that records the load measured in the test piece breaking step and the vertical distance between the upper end of the support base and the lower end of the indenter, which is calculated based on the height of the indenter when the indenter comes into contact with the test piece and a load equal to or greater than a threshold is detected by the load measuring device.

[0017] Preferably, after the recording step, the method further comprises a determining step of determining whether or not an abnormality is present in the test based on the distance.

[0018] Furthermore, preferably, in the determining step, the presence or absence of an abnormality in the test is determined based on whether or not the distance recorded in the test to be determined is within an allowable range determined based on an average value calculated from the distances recorded when the test is performed on a plurality of the test pieces.

[0019] Alternatively, preferably, in the determining step, the presence or absence of an abnormality in the test is determined based on whether or not the distance recorded in the test to be determined is within an allowable range.

[0020] Alternatively, preferably, the method further comprises, after the recording step, a strength calculation step of calculating the flexural strength of the test piece by referring to the load and the distance recorded in the recording step. [Effects of the Invention]

[0021] In a testing apparatus and a testing method according to one aspect of the present invention, the load applied to the support base or the indenter measured by a load measuring device during a destructive test of a test piece is stored. Furthermore, the vertical distance between the upper end of the support and the lower end of the indenter is calculated from the height of the indenter when the indenter comes into contact with the test piece and a load equal to or greater than a threshold is detected by the load measuring device. This distance corresponds to the thickness of the test piece. If an abnormality occurs during the test, this distance value will be a value not normally observed, and recording this distance allows the presence or absence of an abnormality in the test to be determined. Furthermore, the flexural strength of each test piece can be calculated with high accuracy based on this distance.

[0022] Therefore, one aspect of the present invention provides a testing device and a testing method that can derive the flexural strength of a test piece with high accuracy. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a perspective view schematically showing a test device. [Figure 2] FIG. 2 is a perspective view schematically showing a support unit. [Figure 3] FIG. 2 is a perspective view schematically illustrating a configuration of a part of a pressing unit. [Figure 4] FIG. 2 is a block diagram schematically illustrating an example of the configuration of a controller. [Figure 5] FIG. 2 is a cross-sectional view showing the testing device in a state where the test piece is supported by the support unit. [Figure 6] FIG. 2 is a cross-sectional view showing the testing device in a state where the test piece is in contact with the support portion of the support stand. [Figure 7] FIG. 10 is a cross-sectional view showing the test device in a state where the test piece is broken. [Figure 8]1 is a flowchart showing the flow of a testing method for conducting a destructive test on a test piece. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, an example of the configuration of a testing device according to this embodiment will be described. Fig. 1 is a perspective view showing a testing device 2 for testing the strength of a test piece.

[0025] The bending strength (transverse strength) of a plate-shaped test piece such as a device chip is measured by the test apparatus 2. The device chips are manufactured, for example, by dividing a silicon wafer along the planned dividing lines, where devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in each area defined by a plurality of planned dividing lines (streets) arranged so as to intersect each other.

[0026] However, there are no limitations on the type, material, shape, structure, size, etc. of the test piece whose strength is measured by the test device 2. For example, the test piece may be a test chip obtained by dividing a wafer in which no devices are formed on the front side and the back side has been ground or polished under predetermined conditions. The results of measuring the strength of such a chip by the test device 2 can be used to select processing conditions for semiconductor wafers, etc.

[0027] The test piece may also be a chip obtained by dividing a substrate made of a material such as a semiconductor other than silicon (SiC, GaAs, InP, GaN, etc.), sapphire, glass, ceramics, resin, or metal.

[0028] The testing apparatus 2 includes a box-shaped lower container (container) 4 formed in the shape of a rectangular parallelepiped. The lower container 4 has a rectangular parallelepiped opening 4b that opens upward on the side of an upper surface 4a of the lower container 4. A support unit 6 that supports a test piece whose strength is to be measured by the testing apparatus 2 is provided inside this opening 4b.

[0029] 2 is a perspective view showing the support unit 6. The support unit 6 includes a pair of support stands 8 that support a test piece. Each of the pair of support stands 8 is formed in a rectangular parallelepiped shape and is arranged spaced apart from each other so that a gap 10 is provided between the pair of support stands 8. The pair of support stands 8 are also arranged so that the longitudinal direction of their upper surfaces 8a is aligned with the first horizontal direction (X-axis direction, front-rear direction). The test piece whose strength is to be measured is placed on the pair of support stands 8.

[0030] On the upper surface 8a of each of the pair of support bases 8, a columnar (rod-shaped) support portion 8b is formed, protruding upward from the upper surface 8a. The support portion 8b is made of a metal such as stainless steel, and is disposed adjacent to the gap 10 so that its length direction is along the X-axis direction. The pair of support portions 8b are disposed spaced apart from each other across the gap 10, and support the lower surface of the test piece. Note that FIG. 2 shows a support portion 8b with a curved upper surface.

[0031] Furthermore, plate-shaped contact members 12 made of a material (such as rubber sponge) that is softer than the support portions 8b may be provided on the upper surfaces 8a of the pair of support bases 8. The pair of contact members 12 are formed in a rectangular shape in a plan view and are provided on both sides of the pair of support portions 8b. In other words, the contact members 12 are each disposed on the opposite side of the gap 10 between the support portions 8b, and the pair of support portions 8b are disposed between the pair of contact members 12.

[0032] The upper surface of the contact member 12 constitutes a contact surface 12a that contacts and supports the test piece. The contact member 12 is arranged so that the contact surface 12a is located above the upper end of the support portion 8b (for example, approximately 1 mm above the upper end of the support portion 8b). Therefore, when the test piece is placed on the pair of support bases 8, the lower surface of the test piece does not contact the support portion 8b but contacts the contact surface 12a of the contact member 12. Details of the contact between the support portion 8b and the contact member 12 and the test piece will be described later (see Figures 4, 5, and 6).

[0033] A support table moving mechanism (support table moving means) 14 is provided on the rear side of the pair of support tables 8, which moves each of the pair of support tables 8 along a second horizontal direction (Y-axis direction, left-right direction) perpendicular to the first horizontal direction. The support table moving mechanism 14 has a rectangular parallelepiped support structure 16, and a pair of guide rails 18 are fixed to the front side (surface side) of the support structure 16 at a predetermined interval along the Y-axis direction.

[0034] A pair of ball screws 20 are provided between the pair of guide rails 18 and are arranged generally parallel to the pair of guide rails 18. A pulse motor 22 that rotates the ball screws 20 is connected to one end of each of the pair of ball screws 20.

[0035] Furthermore, the support base movement mechanism 14 includes a pair of moving plates 24 fixed to the rear sides of the pair of support bases 8, respectively. The moving plates 24 are slidably mounted on a pair of guide rails 18 provided on the front side of the support structure 16, respectively.

[0036] Furthermore, a nut portion (not shown) is provided on each rear surface (back surface) of the pair of moving plates 24. The nut portion provided on one of the pair of moving plates 24 is threadedly engaged with one of the pair of ball screws 20, and the nut portion provided on the other of the pair of moving plates 24 is threadedly engaged with the other of the pair of ball screws 20.

[0037] When the ball screw 20 is rotated by the pulse motor 22, the moving plate 24 threadedly engaged with the ball screw 20 moves in the Y-axis direction along the guide rail 18. This controls the positions of the pair of support bases 8 in the Y-axis direction and the width of the gap 10.

[0038] There are no limitations on the shape, size, etc. of the lower container 4 and the opening 4b shown in FIG. 1, and these may be changed as appropriate depending on the shape, size, etc. of the support unit 6 and the support table moving mechanism 14.

[0039] A pressing unit 26 is provided above the lower container 4. The pressing unit 26 presses the test piece supported by the support unit 6, and measures the load acting on the pressing unit 26 when pressing the test piece.

[0040] 3 is a perspective view showing the pressing unit 26. The pressing unit 26 includes a movable base 28 connected to a moving unit (moving means) 40. A cylindrical first support member 30 is connected to the underside of the movable base 28 and is disposed downward from the underside of the movable base 28, and a load measuring device (load measuring means) 32 such as a load cell is fixed to the lower end of the first support member 30. The load measuring device 32 measures the load applied to the support base 8 or an indenter 38, which will be described next.

[0041] A clamping member 36 is connected to the underside of the load measuring device 32 via a cylindrical second support member 34. The clamping member 36 is formed in a generally gate-like shape when viewed from the front, and has a pair of opposing clamping surfaces 36a. An indenter 38 is fixed between the pair of clamping surfaces 36a to press against the test piece supported by the support unit 6.

[0042] The tip (lower end) of the indenter 38 is formed in a tapered shape that narrows downward. That is, both side surfaces of the tip of the indenter 38 are inclined with respect to the vertical direction. The tip (lower end) of the indenter 38 is also formed in a rounded shape (R-shape) (see FIG. 4). However, the shape of the indenter 38 is not limited to the above.

[0043] The indenter 38 is supported by the clamping member 36 so that its lower end is aligned along the X-axis direction. That is, the lower end of the indenter 38 and the pair of support portions 8b (see FIG. 2) provided on the support unit 6 are disposed substantially parallel to each other.

[0044] Additionally, a moving unit (moving mechanism) 40 that moves the pressing unit 26 in the up-down direction (Z-axis direction, vertical direction) is provided on the rear side (back side) of the pressing unit 26. The moving unit 40 has a rectangular parallelepiped support structure 42, and a pair of guide rails 44 are fixed to the front side (surface side) of the support structure 42 at a predetermined interval along the Z-axis direction.

[0045] A ball screw 46 is provided between the pair of guide rails 44 and is arranged generally parallel to the pair of guide rails 44. A pulse motor 48 that rotates the ball screw 46 is connected to one end of the ball screw 46.

[0046] The rear surface (back surface) of the movable base 28 of the pressing unit 26 is slidably mounted on a pair of guide rails 44. A nut portion (not shown) is provided on the rear surface of the movable base 28, and this nut portion is threadedly engaged with a ball screw 46.

[0047] When the ball screw 46 is rotated by the pulse motor 48, the movable base 28 moves up and down (Z-axis direction, vertical direction) along the guide rail 44. This controls the position of the pressing unit 26 in the Z-axis direction. Then, by moving the pressing unit 26 in the up and down direction by the moving unit 40, the indenter 38 moves closer to and away from the support unit 6 relatively.

[0048] The testing device 2 includes a height measurement unit 54 that measures the height of the pressing unit 26 (indenter 38) relative to the support unit 6 (support base 8). The height measurement unit 54 includes, for example, a scale 58 provided on the front side (surface side) of the support structure 42 so as to be aligned with the guide rail 44, and a reading unit 56 fixed to the moving base 28 of the pressing unit 26. The reading unit 56 is configured with a photoelectric sensor or the like, and moves in the Z-axis direction together with the moving base 28 while facing the scale 58. The reading unit 56 has a function of reading the scale 58.

[0049] The height measurement unit 54 measures the height of the pressing unit 26 (indenter 38) by reading the scale 58 with the reading unit 56. More specifically, when the movable base 28 is raised and lowered to raise and lower the indenter 38, the reading unit 56, which reads the scale 58, rises and lowers together with the movable base 28. The reading unit 56 reads the scale 58, thereby detecting the height of the pressing unit 26 (indenter 38). For example, the height of the indenter 38 relative to the support unit 6 (support base 8) is measured.

[0050] 1, a pair of plate-shaped connecting members 50 are fixed to both side surfaces of the movable base 28. The connecting members 50 are provided downward from the side surfaces of the movable base 28, and the lower ends of the connecting members 50 are located lower than the lower ends of the clamping members 36.

[0051] A pair of upper container support parts 50a that protrude toward the indenter 38 are formed at the lower ends of the pair of connecting members 50. A rectangular parallelepiped upper container (cover) 52 that covers the tip (lower end) of the indenter 38 is fixed between the pair of upper container support parts 50a. The upper container 52 is disposed above the lower container 4, and both side surfaces are supported by the pair of upper container support parts 50a.

[0052] The upper container 52 is made of, for example, a transparent material (glass, plastic, etc.) and is formed in a box shape. A rectangular parallelepiped opening 52b (see FIG. 4) that opens downward is formed in the upper container 52 on the lower surface 52a side of the upper container 52. An indenter insertion hole 52d is formed in the upper surface 52c side of the upper container 52, and the tip of the indenter 38 is inserted into this indenter insertion hole 52d. Therefore, the tip of the indenter 38 is covered by the upper container 52. In FIG. 1, the part of the indenter 38 that is covered by the upper container 52 is shown by a dashed line.

[0053] The upper container 52 is formed to a size that allows it to be inserted into the opening 4b of the lower container 4, and is disposed inside the opening 4b of the lower container 4 in a plan view. The opening 52b (see FIG. 4) of the upper container 52 is also formed to a size that allows it to accommodate the support unit 6. Therefore, when the pressing unit 26 is moved downward by the moving unit 40, the upper container 52 is inserted into the opening 4b of the lower container 4, and the upper side of the support unit 6 is covered by the upper container 52.

[0054] The test device 2 may also include a display unit (display) 60 that displays various types of information. The display unit 60 is configured, for example, with a liquid crystal display (LCD) or an OLED display. The display unit 60 is connected to a controller 62, which will be described next, and displays information transmitted from the controller 62.

[0055] The display unit 60 may further include a touch panel that functions as an input interface used to input various instructions to the controller 62. Alternatively, the test device 2 may include an independent input interface such as a mouse, a keyboard, or an operation panel.

[0056] Furthermore, the test apparatus 2 includes a controller (control unit) 62 that controls each of the components. The controller 62 is configured by a computer including, for example, a processing device and a storage device, and controls each of the elements of the test apparatus 2. The processing device is typically a CPU (Central Processing Unit), and performs various processes required to control each of the elements of the test apparatus 2.

[0057] The storage device includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive or flash memory. The functions of the controller 62 are realized, for example, by the processing device operating in accordance with a program (software) stored in the storage device. However, the controller 62 may also be realized by hardware alone. The functions and configuration of the controller 62 will be further described in detail below.

[0058] A three-point bending test of a test piece can be performed using the above-described test apparatus 2. The bending strength (transverse strength) of the test piece is measured by this three-point bending test. An example of the operation of the test apparatus 2 when measuring the strength of the test piece will be described below.

[0059] Fig. 4 is a cross-sectional view that schematically shows the testing apparatus 2 in a state in which the test piece 11 is supported by the support unit 6. As shown in Fig. 4, the indenter 38 is disposed above the pair of supports 8b so as to overlap the region (gap 10) between the pair of supports 8b. The indenter 38 is also disposed so that its tip (lower end) is aligned along the length direction (X-axis direction) of the support 8b.

[0060] When measuring the strength of the test piece 11, first, the positions of the pair of support stands 8 in the Y-axis direction are adjusted by the support stand moving mechanism 14 (see FIG. 2). The positions of the pair of support stands 8 are adjusted so that a gap 10 of an appropriate width is formed according to the dimensions of the test piece 11, etc. Then, the test piece 11 is placed on the pair of support stands 8. At this time, the test piece 11 is placed so that both end portions are supported by the pair of support stands 8 and the center portion overlaps the gap 10.

[0061] If the lower surface of the test piece 11 comes into contact with the support parts 8b when the test piece 11 is placed on the pair of support stands 8, the lower surface of the test piece 11 may be damaged by the impact at the time of placement. In this case, the strength of the test piece 11 changes, and it may become difficult to measure the strength of multiple test pieces 11 under the same conditions.

[0062] In this embodiment, a contact member 12 made of a flexible material is provided on the upper surface 8a of the support base 8, and the contact surface 12a of the contact member 12 is located higher than the upper end of the support portion 8b. Therefore, when the test piece 11 is placed on the pair of support bases 8, the test piece 11 comes into contact with the contact surface 12a of the contact member 12 without coming into contact with the support portion 8b, and is supported by the contact surface 12a. This prevents the lower surface of the test piece 11 from coming into contact with the support portion 8b and being damaged when the test piece is placed, and suppresses changes in the strength of the test piece 11. However, the contact member 12 does not have to be provided on the upper surface 8a of the support base 8, and the test piece 11 may come into contact with the support portion 8b.

[0063] Next, the pressing unit 26 is lowered by the moving unit (moving mechanism) 40 (see FIG. 3), and the load measuring device 32 (see FIG. 3) starts measuring the load (force in the Z-axis direction) applied to the indenter 38. As the pressing unit 26 is lowered, the tip of the indenter 38 comes into contact with the upper surface of the test piece 11, and the indenter 38 begins to press the test piece 11. Then, the load value measured by the load measuring device 32 begins to increase due to the pressing of the test piece 11.

[0064] When the pressing unit 26 is further lowered, the test piece 11 is further pressed by the indenter 38, the contact member 12 supporting the test piece 11 is deformed, and the test piece 11 is bent. As a result, the underside of the test piece 11 comes into contact with the support parts 8b of the support base 8. FIG. 5 is a cross-sectional view that schematically shows the test apparatus 2 in a state in which the test piece 11 is in contact with the support parts 8b of the support base 8. When the test piece 11 comes into contact with the pair of support parts 8b, the test piece 11 is supported by the pair of support parts 8b, and the load on the indenter 38 that presses the test piece 11 further increases.

[0065] When the pressing unit 26 is further lowered, the test piece 11 is further pressed by the indenter 38 while being supported by the pair of support parts 8b, causing deflection of the test piece 11. When the pressing force applied to the test piece 11 by the indenter 38 exceeds the strength of the test piece 11, the test piece 11 is broken.

[0066] 6 is a cross-sectional view schematically showing the testing apparatus 2 in a state where the test piece 11 has been broken. When the test piece 11 is broken, the load measured by the load measuring device 32 decreases from its maximum value to zero. Therefore, the timing at which the test piece 11 has been broken can be detected from the change in the value of the load measured by the load measuring device 32. Furthermore, the maximum value of the load measured by the load measuring device 32 corresponds to the strength of the test piece 11.

[0067] Specifically, the bending stress value of the test piece 11 is calculated based on the maximum value of the load applied to the indenter 38, the distance between the upper ends of the pair of support portions 8b, and the dimensions of the test piece 11. When the maximum value of the load applied to the indenter 38 pressing the test piece 11 is W [N], the distance between the upper ends of the pair of support portions 8b is L [mm], the width of the test piece 11 (the length of the test piece 11 in the direction perpendicular to the line connecting the pair of support portions 8b (X-axis direction)) is b [mm], and the thickness of the test piece 11 is h [mm], the bending stress value σ of the test piece 11 is σ=3WL / 2bh 2 It is expressed as:

[0068] However, the method for evaluating the strength (flexural strength) of the test piece 11 is not limited to this, and the maximum value W [N] of the load applied to the indenter 38 does not have to be used for the evaluation. For example, the change in the load measured by the load measuring device 32 from when the indenter 38 comes into contact with the test piece 11 until the test piece 11 breaks may be used for evaluating the strength of the test piece 11.

[0069] Here, in order to precisely calculate the strength (flexural strength) of the test piece 11, it is necessary to measure the thickness h [mm] of each test piece 11 before the test piece 11 is broken. However, measuring the thickness of the test piece 11 itself may change the properties of the test piece 11, and measuring the thickness of each test piece 11 is time-consuming and laborious. Therefore, it is conceivable to calculate the flexural strength of the test piece 11 using the thickness of the test piece 11 in the specifications, but since the actual thickness of each test piece 11 will have an error from the specifications, it is still not possible to precisely calculate the flexural strength of each test piece 11.

[0070] Furthermore, when destructive tests are performed one after another on a plurality of test pieces 11 using the test apparatus 2, fragments 11a of the test pieces 11 fly off. Here, when the test piece 11 is pressed by the indenter 38, the upper container 52 is positioned so as to cover the upper side of the test piece 11 and the support unit 6, as shown in FIG. 6. As a result, the fragments 11a of the test piece 11 are prevented from flying off outside the test apparatus 2.

[0071] However, foreign matter such as fragments 11a may fly off inside the upper container 52 and adhere to the support base 8 or the indenter 38. If a further destructive test of the test piece 11 is conducted with foreign matter adhering to the support base 8 or the indenter 38, the test piece 11 may not be properly supported by the support base 8, or the indenter 38 may not press the test piece 11 properly, resulting in the test being conducted in an abnormal state. In this case, a value different from the value that should have been detected for the load applied to the indenter 38 may be detected. As a result, the calculated value of the bending strength may be even less accurate.

[0072] Therefore, in the test apparatus 2 according to this embodiment, information about the thickness of the test piece 11 is acquired at the same time as a destructive test is performed on the test piece 11. When information about the thickness of the test piece 11 is obtained, the calculated strength (flexural strength) of the test piece 11 becomes a more precise value. It also becomes possible to determine whether the test was performed in an abnormal state, such as when foreign matter is attached to the support base 8 or the indenter 38. Below, the test apparatus 2 will be described, focusing on the configuration that contributes to the acquisition of information about the thickness of the test piece 11.

[0073] The testing apparatus 2 according to this embodiment acquires information about the thickness of the test piece 11 using a load measuring device 32 that measures the load applied to the support base 8 or the indenter 38. More specifically, when a destructive test of the test piece 11 is performed, the height of the indenter 38 or the like is identified when a significant load value is detected by the load measuring device 32 as a result of the indenter 38 coming into contact with the test piece 11 supported by the support base 8 (support portion 8b), and the thickness of the test piece 11 is calculated based on this height.

[0074] For example, the threshold value is set to a load value indicating that the indenter 38 has come into contact with the test piece 11. This threshold value is, for example, a value obtained by adding the measurement error of the load measuring device 32 to the load value measured by the load measuring device 32 when the indenter 38 is not in contact with anything. However, the threshold value is not limited to this.

[0075] When the load measuring device 32 detects a load equal to or greater than this threshold, the height measuring unit 54 measures the height of the indenter 38, and the distance in the up-down direction (Z-axis direction, vertical direction) between the bottom end of the indenter 38 and the top end of the support base 8 at this time is calculated.

[0076] The height of the upper end of the support base 8 is specified in advance, and the distance is calculated by subtracting the height of the upper end of the support base 8 from the height of the lower end of the indenter 38. When the test piece 11 is supported by the contact member 12 without being pressed by the indenter 38, the upper end of the support base 8 is the upper end of the contact member 12. Furthermore, the support base 8 does not need to be provided with the contact member 12, in which case the test piece 11 is supported by the support portion 8b. In this case, the upper end of the support base 8 is the upper end of the support portion 8b.

[0077] If the time difference between when the indenter 38 comes into contact with the test piece 11 and when the load value measured by the load measuring device 32 exceeds the threshold value is small enough to be ignored, the calculated distance becomes the thickness of the test piece 11. Also, if a significant amount of time passes between when the indenter 38 comes into contact with the test piece 11 and when the load value measured by the load measuring device 32 exceeds the threshold value, the thickness of the test piece 11 can be calculated more accurately by correcting the calculated distance taking into account the passage of this time.

[0078] In any case, the distance in the up-down direction (Z-axis direction, vertical direction) between the lower end of the indenter 38 and the upper end of the support base 8 when the indenter 38 comes into contact with the test piece 11 and the load value measured by the load measuring device 32 exceeds the threshold value may be stored in the memory unit of the controller 62. This distance is used to determine the presence or absence of abnormalities in the test and to calculate the strength (flexural strength).

[0079] When the indenter 38 continues to descend after coming into contact with the test piece 11, a destructive test of the test piece 11 is carried out. That is, the test piece 11 is broken, and the load applied to the indenter 38 at the time of the breakage is measured by the load measuring device 32. The load applied to the indenter 38 at this time is then stored in the memory unit of the controller 62.

[0080] The controller 62 of the testing device 2 calculates the strength (flexural strength) of the test piece 11 by referring to the vertical distance between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds the threshold value, and the load value when fracture occurs in the test piece 11. More specifically, the thickness of the test piece 11 is derived from this distance, and the bending stress value σ of the test piece 11 is calculated using the method described above.

[0081] Furthermore, the controller 62 of the testing device 2 determines whether or not an abnormality has occurred in the test performed on the test piece 11 based on the vertical distance between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds the threshold value. Determination conditions are stored in advance in the memory unit of the controller 62, and the controller 62 determines whether or not an abnormality has occurred based on this distance and the determination conditions.

[0082] For example, the tolerance for this distance is the judgment condition. If fragments or debris are attached to the support base 8 (support portion 8b) or the indenter 38, when the indenter 38 is lowered toward the test piece 11 supported by the support base 8, the indenter 38 will come into contact with the test piece 11 earlier than expected. In other words, when the indenter 38 comes into contact with the test piece 11, the vertical distance between the upper end of the support base 8 and the lower end of the indenter 38 will be greater than the thickness of the test piece 11. Therefore, if this distance is greater than a predetermined standard, it can be judged that an abnormality has occurred, such as debris adhering to the indenter 38.

[0083] That is, if this distance falls within the allowable range, the controller 62 determines that no abnormality was found in the destructive test performed on the test piece 11. On the other hand, if this distance does not fall within the allowable range, the controller 62 determines that the destructive test performed on the test piece 11 was abnormal. This allowable range corresponds to the range of values ​​that can be detected as this distance under normal conditions, and is determined by taking into consideration, for example, the specified thickness of the test piece 11, variations in thickness, and measurement errors that can occur in this distance. Then, this allowable range is registered in advance in the memory unit of the controller 62 as a judgment condition.

[0084] It should be noted that if the thickness of the test piece 11 on which the destructive test is performed is significantly smaller than the specified thickness, the condition of the test piece 11 itself is inappropriate. In other words, if the vertical distance between the upper end of the support base 8 and the lower end of the indenter 38 when the indenter 38 comes into contact with the test piece 11 is smaller than the allowable range, it is determined that the test piece 11 is thinner than specified. In this case, it is inappropriate to refer to the results of the destructive test performed on this test piece 11 in evaluating the strength (flexural strength) of the test piece 11. Therefore, the test is judged to be abnormal and not referred to when evaluating the strength of the test piece 11, thereby improving the accuracy of the evaluation.

[0085] Furthermore, if the thickness of the test piece 11 on which the destructive test is performed is significantly greater than the specified thickness, the condition of the test piece 11 itself is inappropriate. That is, if the vertical distance between the upper end of the support base 8 and the lower end of the indenter 38 when the indenter 38 contacts the test piece 11 is greater than the allowable range, possible causes include adhesion of fragments to the support base 8, etc., or the test piece 11 being thicker than specified. Regardless of the cause, if this distance is greater than the allowable range, the destructive test is determined to be abnormal. Then, by determining the test as abnormal and not referring to it when evaluating the strength of the test piece 11, the accuracy of the evaluation can be improved.

[0086] Here, the conditions for determining whether or not there is an abnormality in the destructive test (the method for determining whether or not there is an abnormality and the reference range) are not limited to these. The memory unit of the controller 62 may store other methods and reference ranges as determination conditions. For example, the controller 62 calculates the average value of the distances calculated when the tests are carried out on a plurality of test pieces 11 (the distance in the vertical direction between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds the threshold value). Then, the presence or absence of an abnormality in the destructive test is determined by referring to this average value.

[0087] First, while destructive tests are being carried out on a plurality of test pieces 11, the controller 62 accumulates the values ​​of the distances in the vertical direction between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds a threshold value, and then calculates the average value of these distances.

[0088] A setting method for determining the allowable range of this distance based on this average value is registered in advance as a judgment condition in the storage unit of the controller 62. Then, the controller 62 determines the allowable range by referring to this average value using this setting method registered as the judgment condition, and determines whether or not there is an abnormality in the test based on whether or not this distance is within the allowable range in the test to be judged.

[0089] For example, if fragments of the test piece 11 adhere to the support base 8 or the like during repeated destructive testing of multiple test pieces 11, and in some tests, fragments other than the test piece 11 become sandwiched between the support base 8 and the indenter 38, the value of this distance will be significantly larger than the average value. Also, if the thickness of the test piece 11 is outside the specifications, this distance will be a value that significantly deviates from the average value. Therefore, if the allowable range of this distance value is determined based on the average value, the presence or absence of an abnormality can be determined based on whether this distance is within the allowable range for the test being evaluated.

[0090] When destructive tests are performed successively on a plurality of test pieces 11, the presence or absence of abnormalities in the tests performed up to that point may be determined after some or all of the tests have been completed. In other words, the presence or absence of abnormalities in the destructive tests does not have to be determined immediately after the completion of the destructive tests.

[0091] The more destructive tests are performed on the test piece 11, the more effective the average value of the distance in the vertical direction between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds the threshold value becomes as a judgment criterion. Conversely, if the number of destructive tests performed is small, this average value is easily affected by the variation in this distance between the destructive tests, and may not function effectively as a judgment criterion.

[0092] Therefore, it is advisable to carry out a certain number of destructive tests, collect a certain number of these distance values, and once the effectiveness of the average value of these distances as a judgment criterion has increased to a predetermined degree, determine whether or not there are any abnormalities in each of the destructive tests carried out up to that point.

[0093] If it is determined that there is an abnormality in the destructive test, the load value of the load measuring device 32 at the time of the destruction of the test piece 11 in the destructive test in which the abnormality was found is not used to evaluate the strength of the test piece 11. In addition, the test equipment 2 is inspected and cleaned to normalize the test equipment 2. Alternatively, it is checked whether there is an abnormality in the thickness of the test piece 11.

[0094] The functions of the test apparatus 2 described so far are mainly realized by the controller 62. Therefore, the test apparatus 2 will be described again from a different perspective. Below, the functions of the test apparatus 2 will be described as the configuration of the controller 62. FIG. 7 is a block diagram that schematically shows the configuration of the controller 62 of the test apparatus 2 according to this embodiment. Each unit described below is realized by hardware provided in the controller 62 and software executed by the controller 62.

[0095] 7, the controller (control unit) 62 includes a test control section 64 that controls each component of the testing apparatus 2 to perform a destructive test on the test piece 11, and a memory section 70 that stores various information, software programs, etc. The test control section 64 includes a moving unit control section 66 and a load measurement section 68. The memory section 70 includes a distance memory section 72, a load memory section 74, and a judgment condition memory section 76.

[0096] The moving unit control section 66 mainly controls the moving unit 40 to raise and lower the indenter 38. When a destructive test of the test piece 11 is performed, the moving unit control section 66 controls the moving unit 40 to lower the indenter 38. The moving unit control section 66 also controls the height measurement unit 54 (reading section 56) to acquire information regarding the height position of the indenter 38, in particular, the height position of the lower end of the indenter 38.

[0097] The load measuring unit 68 mainly controls the load measuring instrument 32 to measure the load applied to the support base 8 or the indenter 38. When a destructive test of the test piece 11 is carried out, the load measuring unit 68 continues to receive the load values ​​applied to the support base 8 or the indenter 38 from the load measuring instrument 32, and sequentially stores the received load values ​​in a load memory unit 74, which will be described later.

[0098] If the load value measured by the load measuring device 32 exceeds a threshold value when the indenter 38 is lowered by the moving unit 40 controlled by the moving unit control unit 66, the test control unit 64 detects that the indenter 38 has come into contact with the test piece 11. At this time, the test control unit 64 calculates the value of the distance in the vertical direction (Z-axis direction) between the bottom end of the indenter 38 and the top end of the support base 8 from the height of the indenter 38 detected by the height measurement unit 54, and stores this value in a distance memory unit 72, which will be described next.

[0099] The distance memory unit 72 is connected to the test control unit 64 (movement unit control unit 66), and stores the vertical distance between the lower end of the indenter 38 and the upper end of the support base 8 when the load value measured by the load measuring device 32 exceeds a threshold value. This distance value is used to calculate the strength (flexural strength) of the test piece 11, determine whether or not there is an abnormality in the destructive test of the test piece 11, etc.

[0100] The load memory unit 74 is connected to the test control unit 64 (load measurement unit 68) and stores the load measured by the load measuring device 32. Generally, when a destructive test is performed on the test piece 11, the load value observed by the load measuring device 32 begins to rise when the indenter 38 comes into contact with the test piece 11 and increases as the indenter 38 descends. The load value then reaches a maximum value (peak value) when the test piece 11 breaks, and then rapidly decreases. The load memory unit 74 may store this series of load changes, or may store the maximum value of the load observed when the test piece 11 breaks. The load stored in the load memory unit 74 is used for strength evaluation of the test piece 11, as will be described next.

[0101] The controller 62 includes a strength evaluation unit 80 that calculates the strength of the test piece 11 by referring to the load stored in the load memory unit 74 and the distance stored in the distance memory unit 72. The strength evaluation unit 80 calculates the flexural strength of the test piece 11 by the above-mentioned method.

[0102] The judgment condition storage unit 76 stores judgment conditions for judging the presence or absence of an abnormality in a test that destroys the test piece 11 by the test device 2. The judgment conditions stored in the judgment condition storage unit 76 are referenced when the judgment unit 82, which will be described next, judges the presence or absence of an abnormality in the test.

[0103] The controller 62 of the test device 2 includes a judgment unit 82 that judges whether or not there is an abnormality in the test to destroy the test piece 11 based on the distance stored in the distance memory unit 72 (the vertical distance between the lower end of the indenter 38 and the upper end of the support base 8 when the load value exceeds the threshold value).

[0104] For example, the determination unit 82 calculates the average value of the distances stored in the distance memory unit 72 when tests are performed on multiple test pieces 11. The determination condition memory unit 76 then stores, as a determination condition, a setting method for determining an allowable range of the distance based on this average value. For example, the determination condition memory unit 76 stores the magnitude of an allowable difference from the average value for this distance value. The determination unit 82 then determines the allowable range based on this average value and the setting method stored in the determination condition memory unit 76, and determines whether or not there is an abnormality in the test based on whether or not the distance stored in the distance memory unit 72 for the test to be determined is within the allowable range.

[0105] Alternatively, for example, the judgment condition storage unit 76 stores an allowable range of the distance (the distance in the vertical direction between the lower end of the indenter 38 and the upper end of the support base 8 when the load value exceeds the threshold value) as a judgment condition. Then, the judgment unit 82 judges whether or not there is an abnormality in the test based on whether or not the distance stored in the distance storage unit 72 for the test to be judged is within the allowable range.

[0106] Furthermore, the controller 62 includes a display control unit 84 that controls the display unit 60. The display control unit 84 controls the display unit 60 to display various information on the display unit 60. For example, when the strength of the test piece 11 is evaluated by the strength evaluation unit 80, the display control unit 84 causes the display unit 60 to display the evaluation result.

[0107] Furthermore, when the judgment unit 82 judges whether or not there is an abnormality in the destructive test of the test piece 11, the display control unit 84 causes the judgment result to be displayed on the display unit 60. Alternatively, the display control unit 84 may cause the judgment result to be displayed on the display unit 60 only when it is judged that there is an abnormality in the test. An operator (worker) who has noticed the occurrence of an abnormality by checking the display on the display unit 60 can inspect the test device 2, identify the cause of the abnormality, and correct the test device 2. This makes it easier for subsequent tests to be performed normally.

[0108] The test device 2 may include an information providing unit that provides information to the operator in addition to or instead of the display unit 60. In this case, the controller 62 may include an information providing unit that controls the information providing unit in addition to or instead of the display control unit 84. For example, the test device 2 may include a speaker that emits a warning sound or a warning light as the information providing unit. However, the information providing unit is not limited to these.

[0109] According to the configuration of the controller 62 described above, if there is a test that is determined to have an abnormality by the determining unit 82, the strength of the test piece 11 can be calculated with high accuracy by not using this test as the basis for evaluating the strength (transverse strength) of the test piece 11. Furthermore, if the distance stored in the distance memory unit 72 is used in a test that is not determined to have an abnormality by the determining unit 82, the strength of the test piece 11 can be calculated with high accuracy.

[0110] Next, a method for using the test apparatus 2 configured as described above will be described, which involves a test method for performing a destructive test on the test piece 11. FIG. 8 is a flowchart illustrating the flow of each step of the test method for performing a destructive test on the test piece 11 using the test apparatus 2. In this test method, the test piece 11 is placed on the support table 8, and the indenter 38 presses the test piece 11 to destroy it. At this time, the load applied to the support table 8 or the indenter 38 is measured, and the distance in the vertical direction (Z-axis direction) between the upper end of the support table 8 and the lower end of the indenter 38 when the indenter 38 comes into contact with the test piece 11 is recorded. Each step will be described in detail below.

[0111] First, a test piece 11 to be tested is carried into the test apparatus 2, and a placing step S10 is performed in which the test piece 11 is placed on the support table 8. Fig. 4 is a cross-sectional view schematically showing the state of the test apparatus 2 and the test piece 11 in the placing step S10.

[0112] When the support base 8 is equipped with a pair of contact members 12, the test piece 11 rests on and comes into contact with the pair of contact members 12. When the support base 8 is not equipped with contact members 12, the test piece 11 rests on and comes into contact with the pair of support portions 8b. When the test piece 11 is rectangular, the orientation of the test piece 11 is adjusted so that the width direction of the test piece 11 is aligned with the width direction (X-axis direction) of the gap 10.

[0113] After the placing step S10, a test piece breaking step S20 is carried out in which a destructive test is carried out on the test piece 11. Figures 5 and 6 are cross-sectional views that schematically show the state of the test device 2 and the test piece 11 in the test piece breaking step S20. In particular, Figure 5 shows the state when the test piece 11 comes into contact with the support portion 8b of the support stand 8, and Figure 6 shows the state when the test piece 11 is broken.

[0114] In the test piece breaking step S20, first, the moving unit (moving mechanism) 28 starts to lower the indenter 38, and the indenter 38 approaches the support table 8. At this time, the load measuring device 32 also starts to measure the load applied to the indenter 38. When the indenter 38 is lowered, the lower end of the indenter 38 comes into contact with the upper surface of the test piece 11 supported by the support table 8. At this time, the load applied to the indenter 38 starts to increase, and the test piece 11 starts to be pressed by the indenter 38 and deform.

[0115] Then, as the indenter 38 is further lowered while pressing the test piece 11 with the indenter 38, the test piece 11 breaks when the load applied to the test piece 11 by the indenter 38 exceeds the strength of the test piece 11. The load measuring device 32 measures the load on the indenter 38 until the test piece 11 breaks. Generally, the load on the indenter 38 continues to increase until just before the test piece 11 breaks, and when the test piece 11 breaks, the load on the indenter 38 decreases.

[0116] Then, after the start of the test piece breaking step S20, the recording step S30 is started, and the recording step S30 is performed together with the test piece breaking step S20. In the recording step S30, the load measured in the test piece breaking step S20 is recorded. For example, in the recording step S30, the maximum value of the load measured by the load measuring device 32 may be recorded, or the load transition may be measured and recorded. The load recorded here is used for evaluating the strength of the test piece 11.

[0117] Furthermore, in recording step S30, the distance in the vertical direction (Z-axis direction) between the upper end of support base 8 and the lower end of indenter 38 is recorded. This distance is calculated based on the height of indenter 38 when a load equal to or greater than the threshold is detected by load measuring device 32 due to contact of indenter 38 with test piece 11. As described above, the threshold here is the load value indicating contact of indenter 38 with test piece 11. This distance is a value corresponding to the thickness of test piece 11. The recorded distance is used to determine the presence or absence of abnormalities in the test and to evaluate the strength of test piece 11.

[0118] After the recording step S30, a determination step S40 may be performed in which the presence or absence of an abnormality in the test performed in the test piece destruction step S20 is determined based on the distance recorded in the recording step S30. If this distance deviates from the allowable range of values ​​that the thickness of the test piece 11 can take, it is determined in the determination step S40 that there was an abnormality in the test. On the other hand, if this distance is within the allowable range, it is determined that there was no abnormality in the test.

[0119] In the judgment step S40 according to the first example, the presence or absence of an abnormality in the test is judged based on whether the distance recorded in the test to be judged is within an allowable range. This distance is the distance in the vertical direction (Z-axis direction) between the upper end of the support base 8 and the lower end of the indenter 38, calculated based on the height of the indenter 38 when the indenter 38 comes into contact with the test piece 11 and a load equal to or greater than the threshold is detected by the load measuring device 32.

[0120] This distance corresponds to the thickness of the test piece 11. In the judgment step S40 according to the first example, the range of values ​​that the thickness of the test piece 11 can normally take is set as the tolerance range, and if this distance deviates from the tolerance range, it is judged that there is an abnormality in the test. If this distance is smaller than the tolerance range, it is possible that the test piece 11 is thinner than normal for some reason. On the other hand, if this distance is larger than the tolerance range, it is possible that the test piece 11 is thicker than normal for some reason, or that debris or the like is attached to the support base 8 or the indenter 38.

[0121] In the judgment step S40 according to the second example, an average value is calculated from the above-mentioned distances recorded when tests (destructive tests) are conducted on a plurality of test pieces 11. An allowable range for this distance is determined based on the calculated average value. Then, the presence or absence of an abnormality in the test is determined based on whether or not the distance recorded in the test to be judged falls within the allowable range.

[0122] For example, the amount of allowable deviation from the average value of this distance is determined in advance. For example, this distance is allowed to deviate from the average value by 10 μm. In this case, after the average value of this distance is calculated, the allowable range of this distance is a range of 10 μm above and below the average value. However, the allowable range is not limited to this. Then, the presence or absence of an abnormality in the test is determined based on whether the distance recorded in the test to be judged is within this allowable range.

[0123] Furthermore, after the recording step S30, a strength calculation step S50 may be further performed in which the load value recorded in the recording step S30 and the distance are referenced to calculate the flexural strength of the test piece 11. The strength calculation step S50 may be performed only for tests that are determined to be free of abnormalities after the determination step S40, and in this case, it is not necessary to calculate the flexural strength of the test piece 11 for tests that are determined to be free of abnormalities. Alternatively, the strength calculation step S50 may be performed simultaneously with the determination step S40, or may be performed before the determination step S40.

[0124] As explained above, the testing apparatus 2 according to this embodiment stores the load applied to the indenter 38 measured by the load measuring device 32 when a destructive test is performed on the test piece 11. In addition, the vertical distance between the upper end of the support base 8 (support portion 8b) and the lower end of the indenter 38 is calculated from the height of the indenter 38 when the indenter 38 comes into contact with the test piece 11 and a load equal to or greater than a threshold is detected by the load measuring device 32.

[0125] This distance is a value corresponding to the thickness of the test piece 11. If an abnormality occurs during the test, the value of this distance will be a value that is not normally observed, so by recording this distance, it is possible to determine whether or not there is an abnormality during the test. Furthermore, based on this distance, the flexural strength of each test piece 11 can be calculated with high precision.

[0126] In the above embodiment, the case where the indenter 38 and the like are raised and lowered by the moving unit 40 has been described, but one aspect of the present invention is not limited to this. The moving unit 40 may raise and lower the support base 8 instead of the indenter 38, or may raise and lower both the indenter 38 and the support base 8.

[0127] Furthermore, in the above embodiment, the case where the height measurement unit 54 measures the height of the indenter 38 has been described. However, one aspect of the present invention is not limited to this, and the height measurement unit 54 does not need to directly measure the height of the indenter 38, but may instead measure the height of the movable base 28 or the like. In this case, the presence or absence of an abnormality in the test may be determined based on the height of the movable base 28 relative to the support base 8 (the vertical distance between the upper end of the support base 8 and the movable base 28).

[0128] Furthermore, in the above embodiment, a tolerance is set for the vertical distance between the upper end of the support table 8 and the movable base 28 when the indenter 38 comes into contact with the test piece 11, and the presence or absence of an abnormality in the test is determined based on this distance. However, one aspect of the present invention is not limited to this.

[0129] For example, an allowable range may be set for the height of the indenter 38 or the height of the movable base 28 when the indenter 38 comes into contact with the test piece 11, and a determination may be made based on the height of the indenter 38 or the movable base 28. Since the distance between the indenter 38 and the support base 8 is essentially determined uniquely from the height of the indenter 38 or the movable base 28, a determination based on the distance between the indenter 38 and the support base 8 is also made in these cases.

[0130] In the above embodiment, the load measuring device 32 mainly measures the load applied to the indenter 38. However, one aspect of the present invention is not limited to this. That is, the load measuring device 32 may measure the load applied to the support base 8 instead of the indenter 38. Then, when the load applied to the support base 8 exceeds a threshold value, it may be detected that the indenter 38 has come into contact with the test piece 11, and the strength of the test piece 11 may be calculated based on the load applied to the support base 8.

[0131] The load on the support base 8 reflects the load on the indenter 38. Therefore, determinations and calculations based on the load on the support base 8 have the same technical significance as determinations and calculations based on the load on the indenter 38, and produce the same effects.

[0132] The structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0133] 2. Test equipment 4 Lower vessel 4a Top side 4b opening 6 Support Unit 8 Support stand 8a Top 8b Support part 10 Gap 11 Test specimen 11a Debris 12 Contact member 12a Contact surface 14 Support platform movement mechanism 16 Support structure 18 Guide rail 20 ball screw 22 Pulse motor 24 Moving Plate 26 Pressing unit 28 Mobile base 30 first support member 32 Load measuring device 34 Second support member 36 Clamping member 36a Clamping surface 38 Indenter 40 Mobile Units 42 Support structure 44 Guide rail 46 Ball screw 48 Pulse motor 50 Connecting member 50a Upper container support part 52 Upper vessel 52a Bottom side 52b opening 52c top surface 52d Indenter insertion hole 54 Height measurement unit 56 Reading unit 58 scales 60 display units 62 Controller 64 Test control section 66 Mobile unit control section 68 Load measurement section 70 Storage section 72 Distance memory section 74 Load storage section 76 Judgment condition storage section 80 Strength evaluation section 82 Judgment section 84 Display control unit

Claims

1. A test device for performing a destructive test on a plate-shaped test piece, a support base having a pair of support portions that support the lower surface of the test piece; an indenter that presses the test piece supported by the support base from above; a load measuring device for measuring a load applied to the support base or the indenter; a moving unit that moves the indenter toward and away from the test piece supported by the support base; a controller; The controller a load memory unit that stores the load applied to the support base or the indenter measured by the load measuring device when a test is conducted in which the indenter, which is moved by the moving unit, presses the test piece supported by the support base from above to destroy the test piece; a distance memory unit that calculates the vertical distance between the upper end of the support base and the lower end of the indenter based on the height of the indenter when the indenter comes into contact with the test piece supported by the support base during the test and a load equal to or greater than a threshold is detected by the load measuring device, and stores the calculated distance.

2. The controller a determination unit that determines whether or not there is an abnormality in the test that destroys the test piece based on the distance stored in the distance memory unit; 2. The test apparatus according to claim 1, further comprising a judgment condition storage unit that stores judgment conditions that are referenced when the judgment unit judges whether or not an abnormality has occurred in the test.

3. the determination unit calculates an average value of the distances stored in the distance memory unit when the test is performed on the plurality of test pieces, the determination condition storage unit stores, as the determination condition, a setting method for determining an allowable range of the distance based on the average value; The test apparatus according to claim 2, characterized in that the judgment unit determines the allowable range using the average value stored in the judgment condition memory unit and the setting method, and judges whether or not there is an abnormality in the test based on whether or not the distance stored in the distance memory unit in the test to be judged is within the allowable range.

4. the determination condition storage unit stores an allowable range of the distance as the determination condition; 3. The test device according to claim 2, wherein the determination unit determines whether or not there is an abnormality in the test based on whether or not the distance stored in the distance memory unit in the test to be determined is within the allowable range.

5. 5. The testing apparatus according to claim 1, wherein the controller calculates the flexural strength of the test piece by referring to the load stored in the load memory unit and the distance stored in the distance memory unit.

6. A test method for conducting a destructive test on a plate-shaped test piece using a test device comprising: a support base having a pair of support parts for supporting the underside of the test piece; an indenter for pressing the test piece supported by the support base from above; a load measuring device for measuring a load applied to the support base or the indenter; and a moving unit for moving the indenter toward and away from the test piece supported by the support base, a placing step of placing the test piece on the support base; a test piece breaking step in which, after the placing step, the moving unit moves the indenter closer to the support base, and the indenter presses and breaks the test piece while the load measuring device measures the load acting on the support base or the indenter; A test method for a test piece, comprising: a recording step of recording the load measured in the test piece destruction step and the vertical distance between the upper end of the support base and the lower end of the indenter, calculated based on the height of the indenter when the indenter comes into contact with the test piece and a load equal to or greater than a threshold value is detected by the load measuring device.

7. 7. The test strip testing method according to claim 6, further comprising a determining step, after the recording step, of determining whether or not an abnormality is present in the test based on the distance.

8. A test strip testing method as described in claim 7, characterized in that in the judgment step, the presence or absence of an abnormality in the test is judged based on whether the distance recorded in the test to be judged is within an acceptable range determined based on an average value calculated from the distances recorded when the test was conducted on multiple test strips.

9. 8. The test strip testing method according to claim 7, wherein the judgment step judges whether or not there is an abnormality in the test based on whether or not the distance recorded in the test being judged is within an allowable range.

10. 10. A test method for a test piece according to claim 6, further comprising, after the recording step, a strength calculation step of calculating the flexural strength of the test piece by referring to the load and the distance recorded in the recording step.

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