Hardness testing method, hardness testing apparatus, and hardness testing system

Abstract

To provide a hardness testing device capable of improving measurement accuracy. [Solution] The hardness testing apparatus 100 includes an indenter 10 that is pressed into the sample 101, a support shaft 20 that supports the indenter 10 and is movable in the axial direction, a support mechanism 30 that supports the support shaft 20, an actuator 40 that moves the support shaft 20 in the axial direction, a displacement detection unit 50 that detects the displacement of the indenter 10 in the axial direction, a signal processing unit that processes the displacement signal related to the displacement of the indenter 10 detected by the displacement detection unit 50 and the load signal related to the load acting on the indenter 10, and a control unit 70 that controls the operation of the indenter. Before the actual measurement to measure the hardness of the sample 101, the control unit 70 causes the indenter 10 to perform a free-running operation in which it moves the indenter 10 in the pressing direction so that it passes through a virtual surface which is the position where the contact surface of the sample 101 is located, without the indenter 10 coming into contact with the sample 101, and then performs the actual measurement after the free-running operation.

Description

Technical Field

[0001] The present disclosure relates to a hardness test method, a hardness test apparatus, and a hardness test system.

Background Art

[0002] As hardness test apparatuses, for example, a Vickers hardness tester, a durometer, a Shore hardness tester, etc. are known. Such hardness test apparatuses are widely used in industry. The Vickers hardness tester applies a specified load to the object to be measured using an indenter, and measures the amount of plastic deformation of the object to be measured. The durometer and the Shore hardness tester measure the amount of elastic deformation of the sample or the resilience of the sample.

[0003] Also, as a hardness test apparatus, for example, a Martens hardness tester is known. The Martens hardness tester is applied to a material in which both elastic deformation and plastic deformation of the sample occur simultaneously. In the Martens hardness tester, the relationship between the applied load of the indenter and the penetration amount of the indenter into the sample is measured. In the Martens hardness tester, as a result of the measurement, a "load-displacement curve" can be obtained. Using these "load-displacement curves", "Martens hardness" can be derived.

[0004] Also, as a surface hardness measuring apparatus, the technique described in Patent Document 1 is known. The surface hardness measuring apparatus described in this Patent Document 1 includes an indenter, a cantilever on which the indenter is disposed, pushing means for applying a strain to the cantilever and pushing the indenter into the sample, a mounting table for holding the sample, and a displacement meter for measuring the displacement of the indenter and outputting a displacement signal.

[0005] In this surface hardness measuring apparatus, prior to measuring the hardness of the sample based on the pushing force and the pushing depth of the indenter when the indenter is pushed into the sample surface, it is necessary to know the position of the contact point where the indenter and the sample contact, which corresponds to the start position of the measurement.

[0006] In this surface hardness measuring device, in order to set the starting position for measurement, the indenter is set to a reference position, the mounting platform is raised, and the start position for measurement is determined by detecting when the indenter has come into contact with the sample from the change in the output of the displacement signal of the displacement meter.

[0007] Furthermore, the technology described in Patent Document 2 is known as an indenter pressing device. The indenter pressing device described in Patent Document 2 comprises a shaft having an indenter at its tip, two magnets provided on the shaft, an electromagnetic coil fixed between the magnets that generates an internal magnetic field directed in the axial direction of the shaft, and a displacement meter for measuring the displacement of the shaft.

[0008] Furthermore, the technology described in Patent Document 3 is known as a micro-indentation testing apparatus. The micro-indentation testing apparatus described in Patent Document 3 comprises an indenter device that supports an indenter shaft having an indenter and a permanent magnet with a spring, an electromagnetic coil that generates magnetic attraction and repulsion forces on the permanent magnet, a translational movement mechanism provided to allow the electromagnetic coil to move in the direction of movement of the indenter, and a controller having a signal processing unit. The signal processing unit determines the indentation force of the indenter and the indentation force-displacement characteristics based on the position data of the electromagnetic coil, the position data of the permanent magnet, and the value of the current supplied to the electromagnetic coil. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 3624607 [Patent Document 2] Patent No. 6733935 [Patent Document 3] Patent No. 4247796 [Overview of the project] [Problems that the invention aims to solve]

[0010] In conventional testing equipment, the indenter is brought into contact with the sample before the measurement is performed, causing the indenter to penetrate the sample surface. This slight penetration of the indenter due to pre-measurement contact detection becomes a source of error in the final measurement.

[0011] In addition, a problem arises in that contact point detection must be performed before each measurement, which increases the measurement time.

[0012] This disclosure aims to provide a hardness testing method, a hardness testing apparatus, and a hardness testing system that can improve measurement accuracy. [Means for solving the problem]

[0013] The hardness test method relating to this disclosure is: A control process in which the control unit controls the movement of the indenter, The contact surface of the sample is positioned without the indenter coming into contact with the sample. The first section up to the virtual surface and the second section following the virtual surface. A reference measurement step is performed to move the indenter in the pressing direction, thereby acquiring data on the displacement of the indenter and data on the load of the indenter. The indenter is brought into contact with the sample. While moving the indenter in the pressing direction across the first section up to the point where the indenter is in contact with the sample and the second section where the indenter is in contact with the sample This measurement process involves obtaining data on the displacement of the indenter and data on the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step The process includes a step in which the control unit measures the hardness of the sample using [a specific method / tool]. [Effects of the Invention]

[0014] This disclosure provides a hardness testing method, a hardness testing apparatus, and a hardness testing system that can improve measurement accuracy. [Brief explanation of the drawing]

[0015] [Figure 1] It is a schematic diagram illustrating a hardness testing apparatus according to the first embodiment. [Figure 2] FIG. 2(a) is a schematic diagram illustrating the maximum stroke of the indenter in the idle running operation, and FIG. 2(b) is a schematic diagram illustrating the contact point between the sample and the indenter in this measurement. [Figure 3] It is a graph illustrating the relationship between the displacement of the indenter and the indenter load. [Figure 4] It is a diagram showing an enlarged view of the vicinity of the contact point in the graph illustrating the relationship between the displacement of the indenter and the indenter load. [Figure 5] It is a block diagram showing the configuration of the control unit of the hardness testing apparatus according to the embodiment. [Figure 6] It is a block diagram showing the functional configuration of the control unit. [Figure 7] It is a flowchart (part 1) showing the procedure of the hardness testing method according to the embodiment. [Figure 8] It is a flowchart (part 2) showing the procedure of the hardness testing method according to the embodiment. [Figure 9] It is a flowchart (part 3) showing the procedure of the hardness testing method according to the embodiment. [Figure 10] It is an exploded perspective view illustrating a hardness testing apparatus according to the second embodiment. [Figure 11] It is a perspective view showing a support shaft, a pair of leaf springs, and a flat plate electrode, and is a diagram showing the leaf spring of vibration mode 1 of resonance vibration. [Figure 12] It is a perspective view showing a support shaft, a pair of leaf springs, and a flat plate electrode, and is a diagram showing the leaf spring of vibration mode 2 of resonance vibration. [Figure 13] It is a perspective view showing a support shaft, a pair of leaf springs, and a flat plate electrode, and is a diagram showing the leaf spring of vibration mode 3 of resonance vibration. [Figure 14] It is a side view illustrating a hardness testing apparatus according to the third embodiment. [Figure 15] It is a perspective view illustrating a hardness testing apparatus according to the fourth embodiment. [Figure 16] This is a block diagram showing the configuration of the test apparatus, control unit, and input / output unit of the hardness test system according to the embodiment. [Figure 17] This is a block diagram showing the configuration of the control unit of a hardness testing apparatus according to an embodiment. [Figure 18] This table shows an example of materials that can be measured using the hardness testing apparatus according to the embodiment. [Modes for carrying out the invention]

[0016] The hardness testing method, hardness testing apparatus, and hardness testing system according to the embodiments will be described below with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations. In addition, each figure may show mutually orthogonal X-axis, Y-axis, and Z-axis directions. The X-axis direction includes the direction indicated by the arrow and its reverse direction. The Y-axis direction includes the direction indicated by the arrow and its reverse direction. The Z-axis direction includes the direction indicated by the arrow and its reverse direction. In addition, the terms "up" or "down" may be used in the description of the embodiments, but the arrangement of the hardness testing apparatus is not limited to these. For example, the hardness testing apparatus can be used with the top and bottom shown in the figure reversed.

[0017] [Hardness testing apparatus 100 according to the first embodiment] The hardness testing apparatus 100 according to the first embodiment will be described with reference to Figures 1, 5, and 6. Figure 1 is a schematic diagram of the mechanism of the hardness testing apparatus 100 according to the first embodiment. Figure 5 is a block diagram illustrating the control unit 70 of the hardness testing apparatus 100 according to the first embodiment. Figure 6 is a block diagram illustrating the control unit 70 of the hardness testing apparatus 100 according to the first embodiment, divided into functional parts.

[0018] As shown in Figures 1, 5, and 6, the hardness testing apparatus 100 comprises an indenter 10, an actuator 40, a displacement detection unit 50, and a control unit 70.

[0019] The actuator 40 includes a support shaft 20, a support mechanism 30, a movable indenter part 35, magnets 41 and 42, and a coil 43a. The indenter 10 is connected to the support shaft 20. A displacement detection unit 50 is connected to the actuator 40. The displacement detection unit 50 has an electrode 52 connected to the actuator 40 and a fixed electrode 51 fixed to the main body.

[0020] The control unit 70 drives the actuator 40. The control unit 70 measures the displacement of the actuator 40 using the displacement detection unit 50. The control unit 70 performs control, signal processing, and calculations to measure the hardness from the driving force and the displacement. The "driving force" is the driving force of the actuator 40, and may also be the force driving the indenter 10. The "displacement" is the displacement of the indenter 10. The "hardness" is the hardness of the sample 101.

[0021] The control unit 70 shown in Figure 5 is a block diagram of a circuit including analog and digital circuits. The control unit 70 has a data processing unit, a driver 215, an input unit 61, and an output unit 62. The data processing unit has a CPU 211 and a storage unit 212. The input unit 61 receives measurement conditions. The output unit 62 outputs the measurement results.

[0022] The hardness testing apparatus 100 is capable of performing this measurement. In this measurement, the indenter 10 is driven by the actuator 40 and brought into contact with the sample 101. Furthermore, in this measurement, the indenter 10 is pressed into the sample 101 with a driving load value corresponding to the set maximum load value (specified load), and the displacement detection unit 50 detects the amount of indentation displacement. The hardness is then measured using the load amount (data on the load acting on the indenter) and the amount of indentation displacement (data on the displacement of the indenter). This process of bringing the indenter 10 into contact with the sample 101 and detecting the load and displacement amount is referred to as this measurement. The "maximum load value" is one of the setting conditions and is a value that can be set by the user.

[0023] Furthermore, before performing the actual measurement to measure hardness, the indenter 10 can be made to move in the indentation direction without contacting the sample 101, by passing over a virtual surface 103 where the surface (contact surface) 102 of the sample 101 is located.

[0024] This "free running" refers to moving the indenter 10 while the sample 101 is not in contact with the indenter 10. Alternatively, "free running operation" may also refer to operating the indenter through its entire range of motion without the sample 101 mounted on it.

[0025] [Indenter 10] The indenter 10 is attached to one end of the support shaft 20. The indenter 10 is made of a hard material such as diamond or sapphire, and is, for example, a "micro-Vickers indenter" with a square pyramidal tip. The angle of the tip shape of the indenter 10 is, for example, 136 degrees. The tip shape of the indenter 10 conforms to, for example, the "JIS-B-7225 standard".

[0026] The indenter 10 may be, for example, a "Berkovich indenter" with a triangular pyramidal tip. The angle between the center line and the face of the triangular pyramid is, for example, 65.35 degrees. The center line is aligned with the axial direction of the support shaft 20. The tip shape of the indenter 10 may be, for example, one of those described in "ISO-14577-1".

[0027] The indenter 10 moves along with the support shaft 20 in the axial direction of the support shaft 20 and is pressed into the surface 102 of the sample 101. The support shaft 20 extends in the Z-axis direction. The Z-axis direction is an example of the axial direction of the support shaft 20.

[0028] [Support shaft 20] The support shaft 20 supports the indenter 10. The material of the support shaft 20 is preferably a non-magnetic material, for example, a relatively lightweight aluminum alloy.

[0029] [Magnets 41, 42] Magnets 41 and 42 are fixed to the support shaft 20. For example, permanent magnets such as alnico magnets, ferrite magnets, or rare earth magnets with stronger magnetic force, such as samarium cobalt or neodymium iron boron, can be used for magnets 41 and 42.

[0030] [Displacement detection unit 50] A displacement detection unit 50 is connected to the support shaft 20 to detect the displacement of the support shaft 20. The displacement detection unit 50 is connected to the other end of the support shaft 20 and detects the displacement of the support shaft 20. The displacement detection unit 50 is, for example, a capacitive displacement sensor. The displacement detection unit 50 has a pair of parallel plate electrodes 51 and 52. The parallel plate electrodes 51 and 52 may be abbreviated as plate electrodes.

[0031] A pair of flat plates 51 and 52 are positioned apart in the Z-axis direction. One flat plate electrode 51 is fixed to the support frame 31 of the support mechanism 30, and the other flat plate electrode 52 is fixed to the support shaft 20. The flat plate electrode 52 moves in the Z-axis direction together with the support shaft 20. The gap between the pair of flat plates 51 and 52 changes with the displacement of the support shaft 20 in the Z-axis direction. The gap between the pair of flat plates 51 and 52 is preferably 10 μm to 1000 μm.

[0032] The displacement detection unit 50 is a capacitance-changing type displacement detection unit that can detect the change in the gap between the electrodes as a change in capacitance generated between a pair of flat plate electrodes 51 and 52.

[0033] The pair of flat plates 51 and 52 are made of a conductive material and are preferably non-magnetic. The material of the pair of flat plates 51 and 52 may be, for example, an aluminum alloy. The pair of flat plates 51 and 52 are, for example, disc-shaped.

[0034] The displacement detection unit 50 can detect the displacement of the support shaft 20 in the Z-axis direction without contacting it, without affecting the driving load of the support shaft 20. Here, "non-contact" means that the components of the displacement detection unit 50, excluding the flat plate electrode 52, are not in contact with the support shaft 20.

[0035] It is preferable that the displacement detection unit 50 detects the displacement of the support shaft 20 without contacting the support shaft 20.

[0036] The displacement detection unit 50 may include, for example, an oscillation circuit that changes the capacitance value generated between a pair of flat plate electrodes 51 and 52. The displacement detection unit 50 may measure the frequency of the oscillation circuit or the change in this frequency. The displacement detection unit 50 may also measure by applying an AC voltage to the flat plate electrodes 51 and 52, utilizing the reactance of the capacitance value generated at the flat plate electrodes 51 and 52, or the change in this reactance.

[0037] The displacement detection unit 50 does not necessarily have to be equipped with parallel electrodes 51. The displacement detection unit 50 without parallel electrodes 51 may be, for example, a laser displacement meter or a laser Doppler vibrometer. For example, the detection units of the laser displacement meter and the laser Doppler vibrometer may be firmly fixed to the support frame 31 of the support mechanism 30.

[0038] [Actuator 40] The actuator 40 includes, for example, magnets 41 and 42 and an electromagnetic drive mechanism 43. The magnets 41 and 42 are mounted on the support shaft 20. The magnets 41 and 42 are spaced apart in the axial direction of the support shaft 20. The magnets 41 and 42 are permanent magnets. The magnets 41 and 42 may be, for example, alnico magnets, ferrite magnets, or rare earth magnets with stronger magnetic force, such as samarium cobalt or neodymium iron boron.

[0039] The electromagnetic drive mechanism 43 includes a coil 43a arranged around the support shaft 20 and magnets 41 and 42. The actuator 40 may be, for example, a plunger solenoid. The coil 43a consists of copper wire wound around the support shaft 20. In the actuator 40, a magnetomotive force is generated by exciting the coil 43a. In the actuator 40, the magnetomotive force from the coil 43a and the attractive or repulsive force between the magnets 41 and 42 move the support shaft 20 in the Z-axis direction.

[0040] [Indentation load] In actuator 40, an indentation load can be efficiently generated by arranging multiple magnets 41 and 42. The term "indentation load" may sometimes be written as "indenter load."

[0041] Among the measurement conditions (setting conditions) set by the user of the hardness testing apparatus 100 is the drive load value ("maximum indentation load (value)"). The hardness testing apparatus 100 according to this embodiment is a load-controlled device that measures the hardness of a sample 101 using the "load-displacement curve" obtained when the indenter 10 is pressed into the sample 101 with the drive load value set by the user. A "load-controlled device" is a device that can control the indentation load. As described above, the user can set the drive load value.

[0042] [Device Compliance] In order to accurately detect the minute amount of needle penetration (indentation displacement) and the minute applied load required to do so by pressing the indenter 10 into the sample 101 with a specified load, the support frame 31 should be firmly fixed to the main body of the hardness testing apparatus 100 and have a highly rigid structure. The main body of the hardness testing apparatus 100 includes the housing.

[0043] The main body of the hardness testing apparatus 100 has high rigidity, so elastic deformation of the main body is suppressed. Therefore, it is possible to obtain an accurate value for the minute penetration depth of the indenter 10 in relation to the specified load. The main body of the hardness testing apparatus 100 includes a support frame 31, which has high rigidity and is firmly fixed to the housing of the apparatus.

[0044] [Support mechanism 30] The support mechanism 30 shown in Figure 1 includes, for example, a support frame 31. The support frame 31 is fixed to the housing of the hardness testing apparatus 100. The support mechanism 30 supports the support shaft 20 via the indenter movable part 35.

[0045] [Indenter movable part 35] The indenter movable part 35 has a leaf spring 36. The leaf spring 36 is fixed to the support frame 31 and supports the support shaft 20. The thickness direction of the leaf spring 36 is along the Z-axis direction. The leaf spring 36 extends in the X-axis direction or the Y-axis direction. The support shaft 20 is connected to the leaf spring 36. The support shaft 20 extends on both the upper and lower sides of the leaf spring 36. The support shaft 20 may be divided in the Z-axis direction and connected via the leaf spring 36.

[0046] [Leaf spring 36] The leaf spring 36 is formed from a spring material, such as phosphor bronze. By laser processing the spring material, the leaf spring 36 can be formed with high dimensional accuracy. Furthermore, by annealing the spring material, the internal stress of the spring material can be reduced, and a leaf spring 36 with stable bending rigidity (spring constant) can be obtained. The indenter movable part 35 may be equipped with one leaf spring 36, or it may be equipped with two or more leaf springs 36.

[0047] A soft material that can absorb vibrations well, such as a silicone-based gel, may be brought into contact with the leaf spring 36. This allows for the absorption of vibrations from the leaf spring 36, which could become measurement noise during hardness measurement.

[0048] [Movable part 105 of the hardness testing device 100] The hardness testing apparatus 100 has a movable part 105. The movable part 105 includes an indenter 10, a support shaft 20, magnets 41 and 42, and a flat plate electrode 52. A vibration damping material may be applied to the spring portion of the movable part 105. This allows the movable part 105 to have a vibration damping function. For example, by attaching a silicon-based material to the leaf spring 36, excess vibration of the movable part can be suppressed.

[0049] [Electromagnetic drive mechanism 43] The electromagnetic drive mechanism 43 generates a magnetic field, which creates an attractive or repulsive force on the magnets 41 and 42. This attractive or repulsive force is transmitted to the support shaft 20. The support shaft 20 is displaced, deforming the leaf spring 36, which determines the driving load value (pressing load) of the indenter 10. The amount of movement of the indenter 10 is uniquely determined by the force pushing the support shaft 20 downward and the bending stiffness (spring constant) of the leaf spring. There is a one-to-one proportional relationship between the amount of deformation of the leaf spring 36 and the driving load value of the indenter 10. In other words, the relationship between the amount of deformation of the leaf spring 36 and the driving load value of the indenter 10 can be represented by a load-displacement curve. Therefore, when the leaf spring 36 deforms, the driving load value of the indenter 10 corresponding to the amount of deformation is determined.

[0050] [Sample 101] Sample 101 is the object to be measured for hardness. Sample 101 is placed on the sample stage 104 for measurement. Sample 101 has a shape and size that allows it to be placed on the sample stage 104.

[0051] The hardness testing apparatus 100 includes a sample stage 104 on which a sample 101 can be placed. The hardness testing apparatus 100 may also include a micro-optical system or a camera for image capture that allows for magnified observation of the measurement point. The "measurement point" refers to the point where the tip of the indenter 10 contacts the surface of the sample 101.

[0052] Sample 101 may be, for example, a metallic material, a non-metallic material (rubber, elastomer, plastic), a micro-electronic component, a thin film, a brittle material (glass, ceramics, etc.), various fibers (optical fibers, carbon fibers, etc.), or a fine powder. Sample 101 may also be a surface treatment layer such as an ion implantation layer or a nitride layer.

[0053] [Electromagnetic drive mechanism 43] Next, a hardness test method according to an embodiment will be described. The hardness test method can be performed using the hardness test apparatus 100 according to the first embodiment described above. The hardness test method may also be performed using the hardness test apparatus 100 according to the second to fourth embodiments described later.

[0054] [Load signal] The hardness testing apparatus 100 shown in Figure 1 detects a load signal. The load signal is the coil drive current value. The "coil drive current value" is the current value supplied to the coil 43a. The coil drive of the actuator 40 is driven by current control. Current control means controlling the current supplied to the coil 43a. The current value supplied to the coil 43a is, for example, greater than 0A and up to about 10A. The resistance value between the terminals of the coil 43a is approximately a few ohms. The drive voltage supplied to the coil 43a is, for example, between 3V and 30V.

[0055] [Calibration of measurement values] During the manufacturing process of the hardness testing apparatus 100, the actual test load generated may vary from one apparatus to another. In particular, variations in coil manufacturing can cause changes in the test load. To manufacture a hardness testing apparatus with stable performance, it is necessary to individually and precisely measure the test load for each apparatus. Specifically, the apparatus is manufactured through a calibration process in which the test load is directly measured using an external load cell separate from the hardness testing apparatus body. In the load value calibration process, the indenter 10 is brought into direct contact with the load cell to apply a load, and the relationship between the measured value from the load cell and the drive current value of the coil 43a is captured as calibration data.

[0056] By performing a calibration process for the test load value, the relationship between the drive current value of the coil 43a and the force acting on the indenter 10 can be accurately determined. In the calibration process, the measurement environment is prepared, and for example, measurements are taken five times, and the average value of these measurement results is determined as the load value.

[0057] [Maximum indentation load (maximum load value)] The user of the hardness testing apparatus 100 can set the maximum indentation load (maximum load value) as a measurement condition (setting condition) for the hardness test method. The "driving load value" is a value corresponding to the maximum load value, which is the setting condition, and is the value of the load applied to the indenter 10 in the hardness test method. In the hardness test method, a driving load is applied to the indenter 10.

[0058] [Air travel and operation of the indenter 10 in this measurement] Figure 2(a) is a schematic diagram illustrating the maximum stroke of the indenter 10 during the idle phase, and Figure 2(b) is a schematic diagram illustrating the contact point of the indenter 10 during the main measurement. As described above, the hardness testing apparatus 100 performs an idle phase separately from the main measurement.

[0059] As shown in Figure 2(b), in this measurement, the sample 101 to be measured is placed on the sample stage 104. The indenter 10 moves in the Z-axis direction and is pressed into the sample 101. As the indenter 10 is pressed into the sample 101, a contact point is formed on the surface 102 of the sample 101. The contact point is the moment when the indenter 10 contacts the surface 102 of the sample 101, and is the position where the needle penetration depth is zero.

[0060] As shown in Figure 2(a), during the idle operation, the sample 101 is not placed on the sample stage 104. During the idle operation, the indenter 10 moves in the Z-axis direction by the maximum stroke. The maximum stroke L10 is the maximum range of movement that the indenter 10 can move. The indenter 10 can move in the Z-axis direction, for example, from point P11 to point P12. Point P11 is the point furthest from the sample stage 104 within the range of movement of the indenter 10. Point P12 is the point closest to the sample stage 104 within the range of movement of the indenter 10. The maximum stroke L10 is the distance the indenter 10 moves from point P11 to point P12.

[0061] Point P11 is above the virtual surface 103 of the sample 101. The virtual surface 103 of the sample 101 is a virtual surface corresponding to the surface 102 of the sample 101 when the sample 101 is placed on the sample stage 104. Point P12 is below the virtual surface 103 of the sample 101. Point P12 is closer to the sample stage 104 than the virtual surface 103. During the idle motion, the indenter 10 moves so as to pass over the virtual surface 103. Note that the measurement during the "idle motion" is sometimes referred to as the "reference measurement".

[0062] In the hardness testing apparatus 100, prior to the main measurement of the hardness of the sample 101, the indenter 10 is moved to the maximum range of its movement from the starting point to the ending point of the indenter 10, without the sample being loaded and without the indenter 10 coming into contact with the sample 101. In the hardness testing apparatus 100, the relationship between the load required to indent the indenter 10 and the amount of movement of the indenter 10 is stored in the apparatus as a "load-displacement curve," and this measurement is used as the reference measurement.

[0063] In the hardness testing apparatus 100, by performing a reference measurement at least once before starting the main measurement, the position of the contact point P13 between the sample 101 and the indenter 10 can be accurately and stably detected, as described later. The position of the contact point P13 may be a point within the virtual surface 103.

[0064] In the hardness testing apparatus 100, by performing a free run and conducting a reference measurement without contacting the indenter 10 with the sample, the following factors causing variations in measurement results can be minimized. Measurement values ​​may fluctuate due to aging of the hardness testing apparatus 100 or changes in the temperature and humidity of the environment in which measurements are taken using the hardness testing apparatus 100. In the hardness testing apparatus 100, more accurate measurements can be achieved by performing the reference measurement as close to the main measurement as possible.

[0065] In the hardness testing apparatus 100, by utilizing reference data which is the result of a reference measurement, it is possible to minimize temperature fluctuations in the magnetic field generated by temperature changes of the solenoid coil 43a of the electromagnetic drive mechanism 43, temperature fluctuations in the fixed magnetic fields of the magnets 41 and 42 fixed to the support shaft 20, and temperature fluctuations in mechanical properties such as the spring constant of the leaf spring 36.

[0066] In the hardness testing apparatus 100, while the indenter 10 is operating during the measurement, the reference data and the measurement data are sequentially compared and monitored in real time.

[0067] [Relationship between displacement of indenter 10 and indenter load (Part 1)] Figure 3 is a graph (part 1) illustrating the relationship between the displacement of the indenter 10 and the indenter load. In Figure 3, the horizontal axis shows the displacement of the indenter 10, and the vertical axis shows the indenter load. "Indenter load" refers to the load applied to the indenter 10. Graph G31 shows the indenter load in the reference measurement. The indenter load in the reference measurement is proportional to the displacement. Graph G32 shows the indenter load in the actual measurement. The section from point P11 to point P13 is designated as the first section, and the period from point 13 to point 12 is designated as the second section.

[0068] In the first section, graphs G31 and G32 are the same. At point P13, graphs G31 and G32 diverge. After the displacement exceeds point P13, in the second section, the indenter load in graph G32 is greater than the indenter load in graph G31.

[0069] [Difference between the indenter load in this measurement and the indenter load in the reference measurement] When the displacement of the indenter 10 exceeds point P13, the difference between the indenter load in this measurement (graph G32) and the indenter load in the reference measurement (graph G31) increases. In the second section, when the displacement of the indenter 10 is large, the difference in indenter load is larger compared to when the displacement of the indenter 10 is small.

[0070] In measurements using the hardness testing apparatus 100, the comparison of data from both the reference measurement and the actual measurement is performed by comparing the indentation load value F for each position of the indenter 10 with the load value of the reference data. The difference between the load value in the actual measurement and the load value in the reference data can be continuously calculated and monitored during the measurement. The hardness testing apparatus 100 can detect when this load difference value exceeds the ΔF value (difference load value) predetermined in the measurement conditions.

[0071] In the hardness testing apparatus 100, the position of the displacement of the indenter 10 at the moment when the difference value exceeds the ΔF value is defined as the contact position with the sample 101. Since the reference data is obtained by free running, the indenter 10 is not subjected to any external force throughout the entire range from the start position to the end position, so there are no inflection points (local change points) in the "load-displacement curve".

[0072] In this measurement data, the free-travel section (first section) before the indenter 10 contacts the surface of the sample is the same as the reference data. However, when it contacts the sample 101, the indentation load value changes slightly, creating a difference from the reference data and determining the contact position.

[0073] In the hardness testing apparatus 100, once the contact position with the sample 101 is determined, the maximum indentation load of the indenter 10 is determined by the maximum indentation load value of the pre-specified measurement conditions. While the indenter 10 is operating during the measurement, the contact position is recognized, and the indenter 10 is moved up to the maximum indentation load to penetrate the sample 101. The load value from the point where the indenter contacts the sample is the indentation load value. This will be explained in more detail later.

[0074] [Slope of indenter load (graphs G31, G32)] In the reference measurement, the slope of graph G31 representing the indenter load is constant in the first and second sections. In this measurement, the slope of graph G32 representing the indenter load in the second section is greater than the slope of graph G32 representing the indenter load in the first section. In the first section, the slope of graph G32 representing the indenter load in this measurement is the same as the slope of graph G31 representing the indenter load in the reference measurement.

[0075] Specifically, the comparison of the two sets of data involves comparing the increment rate of the indentation load value F at each position of the indenter 10 (the slope of the load-displacement curve) with the increment rate of the load value at the same position in the reference data (the slope of the load-displacement curve).

[0076] The position of displacement of the indenter 10 at the moment it is detected that the rate of change in inclination (rate of inclination change) obtained in this measurement exceeds the rate of change in inclination (rate of inclination change) predetermined in the measurement conditions is defined as the contact position with the sample 101.

[0077] Because the reference data is based on a free-running motion, the indenter 10 is not subjected to any external force throughout the entire range from the starting position to the ending position, so there are no inflection points (local points of change) in the "load-displacement curve".

[0078] In this measurement data, the free-travel section of the indenter 10 is the same as the reference data, but when it comes into contact with the sample 101, the indentation load value changes slightly, causing a change in the ratio of the load value increase compared to the reference data, and thus determining the contact position.

[0079] In the hardness testing apparatus 100, once the contact position with the sample 101 is determined, the maximum indentation load of the indenter 10 is determined by the maximum indentation load value of the pre-specified measurement conditions. While the indenter 10 is operating during the measurement, the contact position is recognized, and the indenter 10 is moved and inserted up to the maximum indentation load.

[0080] [Fitting curve near the contact point] As will be described later, the displacement detection unit 50 and actuator 40 shown in Figure 5 use either an AD converter or a DA converter. These conversion speeds have limitations, and the acquired data is discrete. The fitting process using the fitting function 227 shown in Figure 6 improves the resolution of the acquired measurement data and enables stable detection of the contact point. Figure 4 is a graph illustrating the relationship between the indenter displacement and the indenter load, showing a magnified view of the area near the contact point.

[0081] The hardness testing apparatus 100 can perform detection using functions. The load-displacement curve from the reference measurement is defined as the first function, and the load-displacement curve from the current measurement is defined as the second function. The functional form representing each curve is defined, and specifically, based on the acquired data, the function is determined by the least squares method or the nonlinear least squares method. By comparing these two functions, the rising point and the slope of the "load-displacement curve" (G32) when the indenter makes contact and during needle insertion can be determined. The rising point can be determined by the point where the difference between the first and second functions suddenly becomes large, or by the point where the radius of curvature of the second function is smallest.

[0082] The first function can be a linear function, a quadratic function, or an even higher-order nth-degree function. The second function can be a quadratic function, an even higher-order nth-degree function, an exponential function, a logarithmic function, or a combination of numerical functions, logarithmic functions, spline functions, or piecewise linear functions.

[0083] Alternatively, using the load-displacement curve obtained from this measurement, the "load-displacement curve" (G31) before contact between the sample 101 and the indenter 10 is defined as the third function, the "load-displacement curve" (G32) when the sample 101 and the indenter 10 are in contact and during insertion is defined as the fifth function, and the connecting part near the transition between these two lines is defined as the fourth function. These three intervals can then be represented by separate functions, and graphs G31 and G32, along with the data, can be used as functions to represent the shape of the rising curve. These functions can then be fitted using the least squares method, and the rising point can be defined by comparing it with the first function or by the shape of the fitted curve, thereby determining the contact position of the indenter.

[0084] The third and fifth functions can be linear functions, quadratic functions, or even higher-order nth-degree functions. The fourth function can also be a simple function such as a quadratic function or an even higher-order nth-degree function. While the division points can also be determined using a nonlinear least squares method, it is also possible to find approximate starting points using a two-interval piecewise linear function, determine the divisions from these provisional starting points, and then determine only the fourth function for the connecting portion using the least squares method.

[0085] In the hardness testing apparatus 100, for example, the rising point is defined using the point where the curvature of the function is maximum. Alternatively, the rising point can be defined using the point where the second derivative of the function is maximum. Furthermore, the hardness testing apparatus 100 may define the midpoint between the two points mentioned above. The rising points defined by these functions are uniquely determined by a predetermined arbitrary value, without the definition point changing, similar to the methods described above using "difference" or "rate of change".

[0086] [Determination of the point of maximum load] In the hardness testing apparatus 100, once the contact position with the sample 101 is determined, the maximum indentation load value (driving load value) of the indenter 10 is determined by a predetermined maximum indentation load (maximum load value). In the hardness testing apparatus 100, the contact point is recognized while the indenter 10 is operating during the measurement, and the indenter is pressed down to the maximum indentation load (which becomes the driving load value).

[0087] [Configuration of the control unit of the hardness testing device 100] Next, with reference to Figure 5, the configuration of the control unit 70 of the hardness testing apparatus 100 according to the embodiment will be described. Figure 5 is a block diagram showing the configuration of the control unit 70 of the hardness testing apparatus 100 according to the embodiment. As shown in Figure 5, the hardness testing apparatus 100 includes a control unit 70.

[0088] The displacement detection unit 50 includes a circuit that obtains a position signal from the change in capacitance between electrodes 51 and 52, and an AD converter that converts the analog signal into a digital signal. The displacement detection unit 50 transmits the digital signal to the control unit 50. The "position signal" is a signal indicating the position of the indenter 10 and is an example of "data related to the displacement of the indenter 10".

[0089] The control unit 70 shown in Figure 6 includes a signal processing function 221. The signal processing function 221 processes the displacement signal related to the displacement of the indenter 10 detected by the displacement detection unit 50, and the load signal related to the load acting on the indenter 10. The control unit 70 controls the operation of the indenter 10.

[0090] As shown in Figure 5, the control unit 70 includes a CPU 211 and a memory unit 212. The CPU 211 is an example of a signal processing unit. The memory unit 212 includes a ROM 213 (Read Only Memory) and a RAM 214 (Random Access Memory).

[0091] The control unit 70 includes a displacement data generation circuit connected to the parallel electrodes 51 and 52. The control unit 70 has the function of acquiring displacement data from a digital recording device that stores displacement data and numerically calculating a load-displacement curve.

[0092] The various functions of the control unit 70 can be realized by reading a program recorded in the ROM 213 or the like into the main memory and executing it by the CPU 211. The CPU 211 of the control unit 70 can read and store data from the RAM 214 as needed. However, some or all of the control unit 70 may be realized by hardware alone. Also, the control unit 70 may be physically composed of multiple devices. For example, a personal computer can be used as the control unit 70. Furthermore, the control unit 70 may also have a "digital displacement data generation circuit," a "digital displacement load generation circuit," a "load-displacement curve calculation function," a "graph drawing function," and a "digital recording device function."

[0093] [Functional configuration of the control unit 70] Next, the functional configuration of the control unit 70 of the hardness testing apparatus 100 will be described. Figure 6 is a block diagram showing the functional configuration of the control unit 70. The control unit 70 includes, for example, a signal processing function 221, a condition setting function 222, a contact point detection method selection function 223, a displacement detection processing function 224, a difference calculation function 225, a tilt change rate calculation function 226, a fitting function 227, a comparison function 228, a load-displacement curve creation function 229, a maximum indentation position calculation function 230, a hardness calculation function 231, and a contact position detection function 232.

[0094] The memory unit 212 includes a first load-displacement curve memory function 241, a second load-displacement curve memory function 242, and a measurement condition memory function 243.

[0095] The signal processing function 221 processes the displacement signal related to the displacement of the indenter 10 detected by the displacement detection function 50, and the load signal related to the load acting on the indenter 10. The condition setting function 222 allows setting, for example, the maximum indentation load as a measurement condition in the hardness testing device 100. The contact point detection method selection function 223 allows selecting one of several contact point detection methods. For example, the contact point detection method selection function 223 allows selecting one of the following: a contact point detection function using the difference, a contact point detection function using the slope change rate, and a contact point detection function using a fitting curve.

[0096] The displacement detection processing function 224 can detect changes in capacitance between a pair of flat plate electrodes 51 and 52 and calculate the displacement of the indenter 10. The difference calculation function 225 continuously calculates the difference between the load value in this measurement and the load value in the reference data during this measurement.

[0097] The slope change rate calculation function 226 calculates the increment rate of the indentation load value F for each position of the indenter 10 (slope of the load-displacement curve). The slope change rate calculation function 226 also calculates the slope of the indenter load graph G31 in the reference measurement and the slope of the indenter load graph G32 in the current measurement.

[0098] The fitting function 227 uses a third function (G31) and a fourth function (G32), and a function (G33) that can appropriately represent the curves near the transitions between the third and fourth functions. It fits these functions using the least squares method, defines the rising point (0 point) using the fitted curve, and calculates the contact position of the indenter.

[0099] As described above, the hardness testing apparatus 100 can perform detection using functions. The load-displacement curve from the reference measurement is defined as the first function, and the load-displacement curve from the current measurement is defined as the second function. The functional form representing each curve is defined, and specifically, based on the acquired data, the function is determined by the least squares method or the nonlinear least squares method. By comparing these two functions, the rising point and the slope of the "load-displacement curve" (G32) when the indenter makes contact and during insertion can be determined. The rising point can be determined by the point where the difference between the first and second functions suddenly becomes large, or by the point where the radius of curvature of the second function is smallest.

[0100] The first function can be a linear function, a quadratic function, or an even higher-order nth-degree function. The second function can be a quadratic function, an even higher-order nth-degree function, an exponential function, a logarithmic function, or a combination of numerical functions, logarithmic functions, spline functions, or piecewise linear functions.

[0101] Alternatively, using the load-displacement curve obtained from this measurement, the "load-displacement curve" (G31) before contact between the sample 101 and the indenter 10 is defined as the third function, the "load-displacement curve" (G32) when the sample 101 and the indenter 10 are in contact and during insertion is defined as the fifth function, and the connecting part near the transition between these two lines is defined as the fourth function. These three intervals can then be represented by separate functions, and graphs G31 and G32, along with the data, can be used as functions to represent the shape of the rising curve. These functions can then be fitted using the least squares method, and the rising point can be defined by comparing it with the first function or by the shape of the fitted curve, thereby determining the contact position of the indenter.

[0102] The third and fifth functions can be linear functions, quadratic functions, or even higher-order nth-degree functions. The fourth function can also be a simple function such as a quadratic function or an even higher-order nth-degree function. While the division points can also be determined using a nonlinear least squares method, it is also possible to find approximate starting points using a two-interval piecewise linear function, determine the divisions from these provisional starting points, and then determine only the fourth function for the connecting portion using the least squares method.

[0103] The comparison function 228 compares the reference data with the actual measurement data. The load-displacement curve creation function 229 can create a "load-displacement curve" as a result of the reference measurement and a "load-displacement curve" as a result of the actual measurement (see Figure 3).

[0104] The maximum indentation position calculation function 230 calculates the maximum indentation position. The hardness calculation function 231 calculates the hardness of the sample 101.

[0105] The contact position detection function 232 detects the contact point between the indenter 10 and the sample 101. The contact position detection function 232 can detect the contact point using, for example, a first contact point detection function using difference, a second contact point detection function using the rate of change of slope, and a third contact point detection function using function fitting.

[0106] The first contact point detection function can detect a contact point when the difference between the data from the reference measurement and the data from the actual measurement exceeds a first judgment threshold. The second contact point detection function calculates the slope change rate (first change rate) of the data from the reference measurement and the slope change rate (second change rate) of the data from the actual measurement, and can detect a contact point when the second change rate exceeds a second judgment threshold. For example, the contact position detection function 232 may use the first change rate as the second judgment threshold, and may detect a contact point when the second change rate exceeds the first change rate.

[0107] In the third contact point detection function, the external processing PC sequentially acquires load-displacement curve data while the measurement is being performed (while the indenter 10 is moving toward the sample 101). In real time, it constantly compares this with reference data (load-displacement curve during free-running). Therefore, contact is detected when, for example, a difference is found in the comparison result (specifically, when a higher F value is recognized at the same movement position H value). Here, "H value" is the displacement value, which is shown on the horizontal axis of the load-displacement curve shown in Figure 9. "F value" is the indenter load value, which is shown on the vertical axis of the load-displacement curve.

[0108] The first load-displacement curve memory function 241 stores the load-displacement curve based on the reference measurement. The second load-displacement curve memory function 242 stores the load-displacement curve based on the actual measurement. The measurement condition memory function 243 stores the measurement conditions set by the condition setting function 222.

[0109] [Procedure for hardness testing using hardness testing apparatus 100] Next, the procedure for the hardness test method using the hardness test apparatus 100 will be described with reference to Figures 7 to 9. Figures 7 to 9 are flowcharts showing the procedure for the hardness test method according to the embodiment.

[0110] First, the hardness test method involves performing a reference measurement using a free-running motion and then processing (steps S11 to S16) to store that data.

[0111] (Step S11) Setting of measurement conditions The condition setting function 222 of the control unit 70 determines the measurement conditions and sets the determined setting conditions in the hardness testing device 100. The condition setting function 222 sets the maximum load value to be applied to the sample 101 by the indenter 10. The maximum load value may be, for example, 300 mN. The condition setting function 222 sets the time (set time) until the maximum load value applied to the sample 101 by the indenter 10 is reached. The set time until the maximum load value is reached may be, for example, 60 seconds. The set time until the maximum load value is reached may also be, for example, the set time from the start of displacement of the indenter 10 until the maximum load value is reached.

[0112] The condition setting function 222 sets the stop time when the indenter 10 is subjected to the maximum load. The stop time when the maximum load is subjected to the maximum load may be, for example, 10 seconds. The stop time when the maximum load is subjected to the maximum load may also be the time after the load applied to the sample 101 by the indenter 10 reaches the maximum load value and the application of that maximum load value continues. When a user evaluates material creep as a physical property, they can set the "stop time when the maximum load is subjected to the maximum load" and evaluate the amount of creep.

[0113] The condition setting function 222 sets the time (set time) for the indenter 10 to remove the load from the maximum load value. The time for removing the load from the maximum load value may be, for example, 60 seconds. The time for removing the load from the maximum load value is the time from the end of the stop time when the maximum load is applied until the load applied to the indenter 10 becomes 0. It is common for the "time for removing the load from the maximum load value" to be set to the same as the application time.

[0114] (Step S12) Setting of reference measurement conditions Next, the condition setting function 222 sets the reference measurement conditions.

[0115] (Step S13) Performing reference measurement Next, the hardness testing apparatus 100 performs a reference measurement. In the reference measurement, the indenter 10 is run without placing the sample 101 on the sample stage 104, according to the conditions of the reference measurement. The operating speed of the indenter 10 in the reference measurement is determined based on the conditions of the reference measurement. In addition, the operating range of the indenter 10 in the reference measurement is such that the indenter 10 passes through the virtual surface 103, which is the contact surface that comes into contact with the sample 101.

[0116] (Step S14) Acquisition of reference measurement data Next, while the indenter is moving in step S13, the hardness testing device 100 continuously acquires reference measurement data. The hardness testing device 100 acquires a displacement signal related to the displacement of the indenter 10 and a load signal related to the load acting on the indenter 10 as reference measurement data. The measurement interval for the displacement signal of the indenter 10 is mainly determined by the conversion speed of the AD converter of the detection unit 50.

[0117] (Step S15) Creation of load-displacement curve (reference) Next, the load-displacement curve creation function 229 creates a load-displacement curve (reference) based on the reference measurement data obtained in step S14.

[0118] (Step S16) Memory of load-displacement curve (reference) Next, the load-displacement curve creation function 229 stores the load-displacement curve (reference) in the storage unit 212 based on the reference measurement data acquired in step S14.

[0119] Next, sample 101 is loaded, and the process shown in Figure 8 (steps S21 to S27) is performed to measure the hardness of sample 101.

[0120] (Step S21) Sample Set The user of the hardness testing apparatus 100 sets the sample 101 on the sample stage 104. Here, the user wipes the surface 102 of the sample 101 and the sample stage 104. This prevents foreign matter from getting caught between the sample stage 104 and the sample 101. The user also removes any dirt or stains from the surface 102 of the sample 101.

[0121] (Step S22) Selection of contact point detection method Next, the contact point detection method selection function 223 selects a contact point detection method. The contact point detection method selection function 223 may select a contact point detection method based, for example, on an input operation by the user.

[0122] (Step S23) Selection of the first contact point detection method; condition determination; YES / NO (Step S23; YES) Next, the control unit 70 determines whether the first contact point detection method is selected. If the first contact point detection method is selected, the control unit 70 executes the process in step S25.

[0123] (Step S23; NO) If the second contact point detection method is not selected, the process in step S24 is executed.

[0124] (Step S24) Selection of second contact point detection method; condition determination; YES / NO The control unit 70 determines whether the second contact point detection method has been selected. (Step S24; YES) The control unit 70 executes the process in step S26 if the second contact point detection method is selected.

[0125] (Step S24; NO) If the second contact point detection method is not selected, the process in step S27 is executed.

[0126] (Step S25) If the determination condition in Step S23 is YES If the first contact point detection method was selected in step S23, the process proceeds to step S25 to perform the measurement.

[0127] (Step S26) If the determination condition in Step S24 is YES If the second contact point detection method was selected in step S24, the process proceeds to step S26 to perform the measurement.

[0128] (Step S27) If the second contact point detection method is not selected in step S24, the process proceeds to step S27 to perform the measurement.

[0129] The control unit 70 sets a first contact point detection method using the difference if the hardness of the sample 101 is relatively hard and the load-displacement curve obtained from the reference measurement is clearly curved. In step S25, the control unit 70 sets the "difference value," which is a predetermined judgment threshold, to, for example, 2 mN. The control unit 70 sets the "difference value" to an extremely small value. The control unit 70 may consider that the indenter 10 is in contact with the sample 101 even if the load value in this measurement has changed only slightly compared to the reference data. This allows the hardness testing device 100 to accurately detect the contact point.

[0130] On the other hand, if the "difference value" is unnecessarily small, the indenter 10 may pick up fluctuations in the load value due to disturbance noise before it contacts the sample 101, and the control unit 70 may mistakenly perceive that the "difference value" is higher than the "measured value" obtained from this measurement. Carelessly making the "difference value" small can cause malfunctions. It is necessary to select the smallest possible value within the range of stable detection.

[0131] The control unit 70 sets a second contact point detection method based on the slope change rate when the hardness of the sample 101 is relatively moderate and the load-displacement curve obtained from the reference measurement is gently curved. In step S26, the control unit 70 sets the predetermined judgment threshold, "slope change rate," to, for example, 0.84. The control unit 70 may also detect a contact point when it determines that the slope change rate has changed by, for example, 16% or more.

[0132] The control unit 70 may change the judgment threshold for the slope change rate depending on, for example, the type of sample 101 or the degree of disturbance vibration. In the hardness test method, it is preferable to set a slope change rate that can stably detect the contact point based on past data. It is preferable to use the repeatability of the Martens hardness result (measured value) to determine whether a stable contact point has been detected. This allows for the setting of a good detection parameter (slope change rate) in the hardness test apparatus 100.

[0133] For example, if the sample 101 is soft, the data showing the inflection of the load-displacement curve from the reference measurement will be very smooth. When the sample 101 is soft, it can be difficult to determine when the indenter 10 made contact with the sample 101 and when penetration began, compared to when the sample 101 is hard. Because the sample 101 elastically deforms with even a small load, it is often difficult to identify the inflection point of the load-displacement curve. In this case, when the sample 101 is soft, the control unit 70 sets a third contact point detection method using function fitting.

[0134] On the other hand, even when the measurement time is set to a very short duration, the number of data points acquired may be small due to data sampling constraints. As a result, the data resolution may become coarse. For example, if the data acquired in this measurement is coarse, it becomes more difficult to identify the inflection point of the load-displacement curve. Thus, by setting a third contact point detection method using function fitting in the hardness testing apparatus 100, contact points can be reliably detected even when the measurement time is short and the number of data points is small.

[0135] In the hardness test method, after performing one of the processes from steps S25 to S27, the process shown in Figure 8 is completed, and then the process shown in Figure 9 (steps S31 to S38) is performed.

[0136] (Step S31) Start of this measurement The hardness testing apparatus 100 performs the measurement. In this measurement, the sample 101 is placed on the sample stage 104. The indenter 10 is operated according to the conditions of this measurement. The operating speed of the indenter 10 in this measurement is determined based on the conditions of this measurement. In addition, the operating range of the indenter 10 in this measurement is such that the indenter 10 passes through the virtual surface 103, which is the contact surface that the indenter 10 makes contact with the sample 101.

[0137] The hardness testing apparatus 100 drives the actuator 40 to start the displacement of the indenter 10. At the same time, it starts acquiring a displacement signal related to the displacement of the indenter 10 and a load signal related to the load acting on the indenter 10 in a continuous manner. Similar to the reference measurement in Figure 9, the measurement interval of the displacement signal of the indenter 10 is mainly determined by the conversion speed of the AD converter of the detection unit 50.

[0138] (Step S32) Contact point detection Next, the hardness testing device 100 detects the contact point (point P13). When the hardness testing device 100 detects a contact point while inserting the indenter 10 into the sample 101, it determines the detected contact position as the zero load point. The "zero load point" is the position where the indentation load applied to the sample becomes zero (i.e., the contact start point).

[0139] The hardness testing apparatus 100 according to this embodiment is based on a load-controlled hardness tester. Therefore, the user evaluates the following items when the desired maximum load value is applied: "load-displacement curve," "maximum indentation amount," "indentation creep amount," and "ratio of elastic to plastic deformation." The hardness testing apparatus 100 clearly determines the "load zero point" and sets the point of maximum indentation load. The hardness testing apparatus 100 can determine the "load zero point" during the measurement by performing the measurement while comparing the measurement with a reference measurement in real time. Therefore, in the hardness testing apparatus 100, the maximum value of the applied load (drive load value), which is the endpoint, is also automatically determined during the measurement. The load control value of the hardness testing apparatus 100 from the "load zero point" to the drive load value (maximum load value) that the hardness testing apparatus 100 should apply to the indenter 10 is called the "endpoint." In other words, the drive load value (maximum load value) applied to the indenter 10 is determined during the measurement. The driving load value (maximum load) applied to the indenter 10 corresponds to the load value at the end point of the load-displacement curve.

[0140] In the hardness testing device 100, the maximum load application position (endpoint) is determined during the operation of the indenter 10 by setting the load zero point (contact point). The "maximum load application position" is the position where the load applied to the indenter 10 is maximum (the position that becomes the driving load value). As described above, the hardness testing device 100 is a "load-controlled device," and the user can set the "maximum load application position" (the driving load value corresponding to the maximum load value). The "maximum load application position" is a setting condition that can be set by the user. The "maximum load application position" is an important load point, along with the "load zero point (contact point)."

[0141] (Step S33) Insert the indenter up to the maximum load value. Next, the hardness testing apparatus 100 inserts the indenter 10 up to the "maximum load value". The hardness testing apparatus 100 inserts the indenter 10 into the sample 101 until the indenter 10 reaches the "maximum applied load position". The "maximum applied load position" is the position where the maximum load value is applied to the sample. The "maximum applied load position" may also be the position from the contact point.

[0142] (Step S34) Stop the indenter until the set holding time is reached. Next, the hardness testing device 100 stops the indenter 10 until the set holding time. The hardness testing device 100 applies a load to the indenter 10, and when the load applied to the indenter 10 reaches the maximum load value, it stops the indenter 10 and holds the indenter 10 for a preset holding time (indentation time). The hardness testing device 100 continues to apply the maximum load value during the preset holding time.

[0143] (Step S35) Unload the indenter until the set time has elapsed. Next, the hardness testing device 100 removes the load from the indenter 10 during a set unloading time. The hardness testing device 100 stops the indenter 10 until a preset holding time has elapsed, and then unloads the indenter 10 during a preset unloading time.

[0144] (Step S36) Creation of load-displacement curve Next, the hardness testing device 100 creates a load-displacement curve (main measurement) through calculation processing of the load-displacement curve creation function 229.

[0145] (Step S37) Memory of load-displacement curve Next, the memory unit 212 of the hardness testing device 100 stores the load-displacement curve (main measurement). The memory unit 212 stores "load application data," "load holding data," and "load removal data" as measurement data. "Load application data," "load holding data," and "load removal data" are, for example, data related to the displacement of the indenter 10.

[0146] (Step S38) Output of hardness results Next, the hardness testing device 100 outputs the hardness result. The hardness testing device 100 calculates the necessary hardness measurement result (Martens hardness), etc., from the load-displacement curve obtained from this measurement and terminates the measurement. The measurement results from the hardness testing device 100 conform to, for example, the international standard ISO-14577-1 (micro-indentation test).

[0147] [Effects and Effects of the Hardness Testing Apparatus 100 According to the Embodiment] The hardness testing apparatus 100 according to the embodiment includes an indenter 10 that is pressed into a sample 101, a support shaft 20 that supports the indenter 10 and is movable in the Z-axis direction, a support mechanism 30 that supports the support shaft 20, an actuator 40 that moves the support shaft 20 in the Z-axis direction, a displacement detection unit 50 that detects the displacement of the indenter 10 in the Z-axis direction, a signal processing function 221 that processes the displacement signal related to the displacement of the indenter 10 detected by the displacement detection unit 50 and the load signal related to the load acting on the indenter 10, and a control unit 70 that controls the operation of the indenter 10. Before the actual measurement to measure the hardness of the sample 101, the control unit 70 causes the indenter 10 to perform a free-running operation in which it moves the indenter 10 in the pressing direction so that it passes through a virtual surface 103 which is the position where the contact surface (surface 102) of the sample 101 is located, without the indenter 10 coming into contact with the sample 101, and then performs the actual measurement after the free-running operation.

[0148] In this type of hardness testing apparatus 100, before the actual measurement, the indenter 10 can be displaced so that it passes through a virtual surface 103 without contacting the sample 101, thereby creating a load-displacement curve. This allows for the stable detection of the contact point position by offsetting fluctuations in the measurement environment on the measurement day, and enables accurate measurement of the hardness of the sample 101.

[0149] Furthermore, in the hardness testing device 100, the signal processing function 221 can calculate a load-displacement curve (first function) that shows the relationship between the displacement signal and the load signal during the free-running motion. As a result, the hardness testing device 100 can detect the contact point using the load-displacement curve obtained from the reference measurement during the free-running motion.

[0150] Furthermore, in the hardness testing apparatus 100, the control unit 70 can move the support shaft 20 over its maximum stroke L10 (the entire range of motion) to perform a free-running motion. This allows for a more accurate creation of the load-displacement curve by displacing the indenter 10 over its maximum stroke L10.

[0151] In the hardness testing apparatus 100, the relationship between the indenter driving force and the displacement of the indenter 10 (indenter driving characteristics) is not necessarily linear, but rather nonlinear (approximately quadratic). In the hardness testing apparatus 100, the contact point of the indenter 10 can be stably detected by always comparing data across the entire range of the nonlinear displacement characteristics.

[0152] The signal processing function 221 of the hardness testing device 100 calculates a second function from the measurement results of this measurement, and detects a zero point by comparing the first function calculated from the measurement results of the reference measurement with the second function. The hardness testing device 100 has a detection unit 232, and after detecting a zero point, the control unit can drive the actuator 40 to apply the maximum load (maximum indentation load value) to the indenter 10.

[0153] The position detection function 232 calculates the difference between the first function and the second function, and if the calculated difference exceeds the first judgment threshold, it sets the score to 0.

[0154] The contact position detection function 232 calculates the slope of the first function, calculates the slope of the second function during the measurement, and sets the score to 0 if the slope of the second function exceeds the second judgment threshold.

[0155] The contact position detection function 232 calculates a third function (G31) before contact in this measurement, calculates a fourth function (G32) after contact, and calculates a fifth function by fitting a curve connecting the straight line based on the third function and the straight line based on the fourth function using the least squares method, thereby detecting the zero point.

[0156] As described above, the hardness testing apparatus 100 can perform detection using functions. The load-displacement curve from the reference measurement is defined as the first function, and the load-displacement curve from the current measurement is defined as the second function. The functional form representing each curve is defined, and specifically, based on the acquired data, the function is determined by the least squares method or the nonlinear least squares method. By comparing these two functions, the rising point and the slope of the "load-displacement curve" (G32) when the indenter makes contact and during insertion can be determined. The rising point can be determined by the point where the difference between the first and second functions suddenly becomes large, or by the point where the radius of curvature of the second function is smallest.

[0157] The first function can be a linear function, a quadratic function, or an even higher-order nth-degree function. The second function can be a quadratic function, an even higher-order nth-degree function, an exponential function, a logarithmic function, or a combination of numerical functions, logarithmic functions, spline functions, or piecewise linear functions.

[0158] Alternatively, using the load-displacement curve obtained from this measurement, the "load-displacement curve" (G31) before contact between the sample 101 and the indenter 10 is defined as the third function, the "load-displacement curve" (G32) when the sample 101 and the indenter 10 are in contact and during insertion is defined as the fifth function, and the connecting part near the transition between these two lines is defined as the fourth function. These three intervals can then be represented by separate functions, and graphs G31 and G32, along with the data, can be used as functions to represent the shape of the rising curve. These functions can then be fitted using the least squares method, and the rising point can be defined by comparing it with the first function or by the shape of the fitted curve, thereby determining the contact position of the indenter.

[0159] The third and fifth functions can be linear functions, quadratic functions, or even higher-order nth-degree functions. The fourth function can also be a simple function such as a quadratic function or an even higher-order nth-degree function. While the division points can also be determined using a nonlinear least squares method, it is also possible to find approximate starting points using a two-interval piecewise linear function, determine the divisions from these provisional starting points, and then determine only the fourth function for the connecting portion using the least squares method.

[0160] Furthermore, during the execution of this measurement, once a contact point is determined, the contact position detection function 232 determines the zero value of the indentation load (drive load value), the maximum indentation load value (drive load value), and the position to which the indenter 10 is pressed, based on that contact point. The control unit 70 determines the position (end point) of the maximum indentation load (maximum load value) as a preset measurement condition, and controls the operation to press the indenter 10 to the determined position (end point) of the maximum indentation load.

[0161] Furthermore, the contact position detection function 232 can detect the contact point during the measurement and determine the position (endpoint) of the maximum indentation load using the maximum indentation load value (driving load value) determined during the measurement.

[0162] "Maximum indentation load" refers to the maximum indentation load value (maximum load value) set by the user as a setting condition. The maximum indentation load value (maximum load value) that the device itself can apply is similar to the device's absolute rating. Furthermore, "load position" may refer to the position on the graph that plots the load-displacement curve.

[0163] Specifically, the point (position) on the graph determined by the maximum applied load value (load value, displacement value) set by the user cannot be determined until the contact point is determined. The "load position" may also be the goal point (point on the graph) of the movement of the indenter 10, which is determined by the measurement conditions and the contact position.

[0164] In the hardness testing apparatus 100 according to this embodiment, it is only necessary to perform a reference measurement once before starting the actual measurement each day. With such a hardness testing apparatus 100, it is possible to offset fluctuations in the measurement environment, such as daily changes in temperature and humidity.

[0165] The hardness testing apparatus 100 can cancel out factors such as fluctuations in the generated magnetic field (magnetomotive force) due to temperature changes in the coil 43a, fluctuations in the fixed magnetic field due to the temperature of the magnets 41 and 42, and temperature fluctuations in the mechanical properties such as the spring constant of the leaf spring 36. With the hardness testing apparatus 100, by understanding the state of the hardness testing apparatus 100 immediately before the actual measurement and reflecting the reference measurement data in the actual measurement, the contact point between the sample 101 and the indenter 10 can be accurately detected.

[0166] As a result, the hardness testing device 100 enables more stable hardness measurement. For example, when measuring multiple samples 101 consecutively, a reference measurement is performed only once on the first day of measurement, and the reference measurement data measured by the hardness testing device 100 at the time of measurement is read from the storage unit 212, thereby enabling efficient hardness measurement of the samples 101. The hardness testing device 100 allows for efficient measurement of the hardness of the samples 101 and rapid measurement of the hardness of multiple samples 101.

[0167] The hardness testing device 100 allows the user to select one of three methods for detecting a contact point: a first contact point detection method based on the difference from reference data, a second contact point detection method based on the slope change rate, or a third contact point detection method based on function fitting. Depending on the material of the sample 101 and the measurement conditions, the hardness testing device 100 can measure the hardness of the sample 101 by selecting the first contact point detection method, the second contact point detection method, or the third contact point detection method. As a result, the hardness testing device 100 can achieve stable hardness measurement.

[0168] The hardness testing apparatus 100 allows for stable detection of the contact point by simplifying the apparatus configuration and the measurement operation within the apparatus. The hardness testing apparatus 100 uses a simple configuration and performs a free-running operation to stably detect the contact point.

[0169] Furthermore, the hardness testing apparatus 100 can perform a third contact point detection method using function fitting. In the measurement conditions of this measurement, when the measurement time is short, the number of measurement data points relating load and displacement becomes relatively small, and the temporal resolution of the acquired data may decrease. The third contact point detection method using function fitting can identify the contact position (contact point) by stably verifying the rise point, regardless of the data resolution in this measurement.

[0170] Furthermore, even when evaluating the hardness of a highly elastic material such as an elastomer, which has a soft hardness, the hardness testing apparatus 100 can clearly detect the point where the indenter 10 contacts the sample 101.

[0171] In the hardness testing apparatus 100 according to this embodiment, a reference measurement is performed, and the measurement is carried out while constantly comparing it with the measurement data during the main measurement using this reference. As a result, the hardness testing apparatus 100 can compensate for environmental fluctuations and stably perform highly accurate measurements.

[0172] The hardness testing device 100 does not require a contact point detection operation on the sample before the actual measurement, and it does not need to perform a contact point detection operation every time a measurement is taken. Therefore, the hardness testing device 100 can shorten the measurement time.

[0173] While hardness testing does not always yield a linear load-displacement relationship, the hardness testing apparatus 100 according to this embodiment can reliably perform contact point detection even when a nonlinear load-displacement relationship is obtained.

[0174] The hardness testing apparatus 100 eliminates the need for various mechanisms required for contact point detection, simplifying the apparatus and enabling a compact and inexpensive device. For example, conventional hardness testing apparatuses that have mechanisms required for zero-index operation require various mechanisms such as (1) a mechanism for moving the sample mounting stage and (2) a microscopic optical system for observing the sample surface. The hardness testing apparatus 100 according to this embodiment does not have (1) a mechanism for moving the sample mounting stage and (2) a microscopic optical system for observing the sample surface. Therefore, the hardness testing apparatus 100 can be simplified, enabling a compact and inexpensive device.

[0175] Zero-index operation is defined as "an operation that causes the hardness testing apparatus 100 to recognize the contact point (height) of the sample between the indenter 10 and the sample 101 prior to the actual measurement." "Zero" means zero indenter insertion depth. "Index" means height information of the indenter 10. The "zero-index operation" specifically includes lowering the indenter 10 to contact the sample 101, or raising the sample stage 104 while keeping the indenter 10 fixed to contact the sample 101. The aforementioned contact operation causes the hardness testing apparatus 100 to recognize the height information (zero index) between the indenter 10 and the surface of the sample 101.

[0176] Next, to prevent the indenter 10 from contacting the same spot on the surface of the sample 101 during the main measurement, the sample stage 104 is slightly shifted laterally. After shifting the sample stage 104 slightly, the measurement operation is performed using the sample contact position (zero point height information) as the sample contact point (zero point) recognized by the zero index operation as the basis for this measurement.

[0177] The hardness testing device 100 can implement a contact point detection method using a fifth function calculation. This contact point detection method using a fifth function calculation allows for the stable determination of the rising point and the determination of the contact position, regardless of the resolution of the acquired data (differences in density due to sampling period).

[0178] For example, when evaluating a sample that is soft and highly elastic, it can be difficult to clearly detect the point where the indenter contacts the sample. In the hardness testing apparatus 100, when the above fifth function is calculated, the contact position can be reliably determined.

[0179] Function 1: Load-displacement curve during idle Second function: Load-displacement curve during actual measurement Third function: Before indenter contact during this measurement (G31 in Figure 3) Function 4: After indenter contact during this measurement (G32 in Figure 3) Fifth function: A function that connects the third and fourth functions (G33 in Figure 4)

[0180] [Challenges of conventional technology] For example, the "surface hardness measuring device" described in Patent Document 1 (Japanese Patent No. 36346) required complex mechanisms for the sample stage below the sample and the vertical lifting mechanism. In the hardness testing device 100 according to this embodiment, the hardness of the sample 101 can be stably measured using a device with a simple configuration.

[0181] In conventional testing equipment, the indenter is brought into contact with the sample before the measurement is performed, causing the indenter to penetrate the sample surface. This slight penetration of the indenter due to pre-measurement contact detection becomes a source of error in the final measurement.

[0182] In addition, a problem arises in that contact point detection must be performed before each measurement, which increases the measurement time.

[0183] [Hardness testing apparatus 100 according to the second embodiment] Next, with reference to Figure 10, the hardness testing apparatus 100 according to the second embodiment will be described. Figure 10 is an exploded perspective view illustrating the hardness testing apparatus 100 according to the second embodiment. Figure 11 is a perspective view showing the support shaft 20, the leaf spring 36, and the electrode 52, and is a diagram showing vibration mode 1 of resonant vibration. Figure 12 is a perspective view showing the support shaft 20, the leaf spring 36, and the electrode 52, and is a diagram showing vibration mode 2 of resonant vibration. Figure 13 is a perspective view showing the support shaft 20, the leaf spring 36, and the electrode 52, and is a diagram showing vibration mode 3 of resonant vibration. The difference between the hardness testing apparatus 100 according to the second embodiment and the 100 according to the first embodiment is that it is equipped with a pair of leaf springs 36. Note that in the description of the hardness testing apparatus 100 according to the second embodiment, explanations similar to those of the hardness testing apparatus 100 according to the first embodiment may be omitted.

[0184] [Leaf spring 36] As shown in Figures 10 to 13, the hardness testing apparatus 100 may include a plurality of leaf springs 36. The hardness testing apparatus 100 may also include a pair of leaf springs 36 that are spaced apart in the Z-axis direction. The pair of leaf springs 36 are positioned between the indenter 10 and the magnet 41 in the Z-axis direction.

[0185] The hardness testing device 100 is equipped with a pair of leaf springs 36, which makes it easier to suppress displacement of the indenter 10 in directions other than translational movement in the indentation direction (Z-axis direction). Specifically, displacement in directions other than translational movement refers to the movement in which the support shaft 20 tilts, and this displacement is easier to suppress. In Figure 12, vibration mode 2 is shown as a resonant vibration mode, and in Figure 13, vibration mode 3 is shown as a resonant vibration mode.

[0186] When the points where the pair of leaf springs 36 are connected to the support shaft 20 are far apart from each other, the tilting motion of the support shaft 20 is easily suppressed. In the hardness testing device 100, it is possible to suppress the extra motion components shown in Figures 12 and 13 without increasing the spring constant of the movable part 105.

[0187] The thickness of the leaf spring 36 may be, for example, 0.1 mm. The spring material of the leaf spring 36 may be phosphor bronze plate. The length of the leaf spring 36 may be 50 mm. In the X-axis direction, both ends of the leaf spring 36 are fixed to the support frame 31. In the X-axis direction, the support shaft 20 is connected to the center of the leaf spring 36. In the Z-axis direction, the connection of the upper and lower leaf springs 36 to the support shaft 20 allows the hardness testing apparatus 100 to obtain a primary resonance in a motion mode in which the support shaft 20 translates in the direction of indentation of the indenter 10. The indentation direction of the indenter 10 is along the Z-axis direction. In Figure 11, Mode 1 is shown as a resonant vibration mode.

[0188] More specifically, the hardness testing apparatus 100 is provided with a pair of leaf springs 36 having the above configuration, for example, Primary resonance frequency: 30Hz (vertical translation), Secondary resonance frequency: 600Hz (axis tilting movement left and right), Tertiary resonance frequency: 700Hz (axis forward and backward tilting movement, A spring-mass system movable part 105 with a spring constant of approximately 1 mm / N can be obtained.

[0189] The hardness testing apparatus 100 can obtain the vibration mode of vertical translational motion at the first resonance, and the resonance frequencies of undesirable vibration components (second and third resonances) can be designed to be on the higher frequency side. As a result, hardness can be measured more accurately even in the presence of external vibrations.

[0190] The control unit 70 in Figure 5 includes a driver 215, a displacement detection unit 50, an input unit 61, and an output unit 62.

[0191] The input unit 61 is for the user to give instructions to the control unit 70 and set necessary measurement conditions, and the output unit 62 is for the control unit 70 to communicate results and measurement status to the user. The input unit 61 and the output unit 62 may also be the input and output units of an external processing PC connected to the signal processing board. The input unit 61 may be, for example, a keyboard or buttons. The output unit may be, for example, a liquid crystal display device.

[0192] The CPU 211 shown in Figure 5 is an arithmetic unit that reads programs and data from storage devices such as ROM 212 onto RAM 214, executes processing, and realizes the overall control and functions of the control unit 70. RAM 214 is a volatile storage device that temporarily holds programs and data. ROM 213 is a non-volatile storage device that can retain programs and data even when the power is turned off. ROM 213 stores processing programs and data that the CPU 211 executes to control each function of the hardness testing device 100.

[0193] The hardness testing device 100 can achieve the functional configuration described later through the instructions of the CPU 211 and the configuration of its mechanical parts.

[0194] The control unit 70 in Figure 17 includes a data processing unit similar to that shown in Figure 5, as in Example 1. The data processing unit A included in the control unit 70 includes a CPU 211 and a storage unit 212. The storage unit 212 has a ROM 213 and a RAM 214, and mainly performs signal processing from the displacement detection unit 50 and controls the coil current to the actuator unit 40 shown in Figure 10.

[0195] On the other hand, the data processing unit B included in the control unit 70 includes a CPU 211 and a memory unit 212. The memory unit 212 has a ROM 213 and a RAM 214, and is responsible for advanced mathematical calculations, graph display, and input / output functions to the keyboard and display device of an external PC.

[0196] The data between data processing unit A and data processing unit B is transmitted via a digital data communication method, such as USB (Universal Serial Bus).

[0197] [Hardness testing apparatus 100 according to the third embodiment] Next, with reference to Figure 14, the hardness testing apparatus 100 according to the third embodiment will be described. Figure 14 is a side view illustrating the hardness testing apparatus 100 according to the third embodiment. Note that in the description of the hardness testing apparatus 100 according to the third embodiment, explanations similar to those for the hardness testing apparatus 100 according to the first and second embodiments described above may be omitted.

[0198] The hardness testing apparatus 100 has a substrate storage section 130 for storing a signal processing board. The hardness testing apparatus 100 also includes a device body 120 that supports the measuring head 110. The measuring head 110 includes the indenter 10, support shaft 20, support mechanism 30, indenter movable part 35, actuator 40, displacement detection unit 50, and control unit 70. The support frame 31 of the support mechanism 30 is firmly connected to the device body 120. The device body 120 has high rigidity and can stably detect weak test loads and minute indenter needle insertion depths.

[0199] The hardness testing apparatus 100 includes a head lifting mechanism 122. The head lifting mechanism 122 can raise and lower the measuring head 110. The indenter 10 described above is located at the lowest part of the measuring head 110. The measuring head 110 is positioned above the sample stage 104. The head lifting mechanism 122 can lower the measuring head 110 to bring the indenter 10 closer to the surface 102 of the sample 101. The head lifting mechanism 122 can raise the measuring head 110 to move it away from the surface 102 of the sample 101. The hardness testing apparatus 100 includes a locking mechanism for locking the raising and lowering of the measuring head 110.

[0200] The hardness testing apparatus 100 is equipped with a signal connector 132. The signal connector 132 is an interface unit that connects the signal processing board and the external processing PC.

[0201] The hardness testing apparatus 100 also includes a handle 140 and a top plate 142. The top plate 142 is fixed to the top of the apparatus body 120. The top plate 142 extends from the apparatus body 120 in the Y-axis direction. The top plate 142 extends so as to cover the top surface of the measuring head 110. The handle 140 is fixed to the top plate 142. The user can carry the hardness testing apparatus 100 by gripping the handle 140.

[0202] [Hardness testing apparatus 100 according to the fourth embodiment] Next, with reference to Figure 15, the hardness testing apparatus 100 according to the fourth embodiment will be described. The hardness testing apparatus 100 according to this embodiment is suitable when the sample to be hardened is large. Figure 15 is a perspective view illustrating the hardness testing apparatus 100 according to the fourth embodiment. The differences between the hardness testing apparatus 100 according to the fourth embodiment shown in Figure 15 and the hardness testing apparatus 100 according to the third embodiment shown in Figure 14 are that it does not have a sample stage 104, the substrate storage section 130 is located on the side of the apparatus body 120, and it has a bottom plate 144. Note that in the description of the hardness testing apparatus 100 according to the fourth embodiment, the same descriptions as those for the hardness testing apparatus 100 according to the first to third embodiments may be omitted.

[0203] The sample 101 may be larger than the hardness testing apparatus 100 in a plan view. The hardness testing apparatus 100 can be used to measure the hardness of the sample 101 by placing the apparatus 100 on top of the sample 101. The hardness testing apparatus 100 does not necessarily have a sample stage 104.

[0204] The substrate storage section 130 is located on the opposite side of the measuring head 110 from the main body 120 in the Y-axis direction. In the Y-axis direction, the measuring head 110, head lifting mechanism 122, main body 120, and substrate storage section 130 are arranged in that order. The signal connector 132 may be provided on the upper surface of the substrate storage section 130.

[0205] The hardness testing apparatus 100 is equipped with a base plate 144. The apparatus body 120 and the substrate storage section 130 are placed on the base plate 144. The base plate 144 is fixed to the bottom surface of the apparatus body 120 and the substrate storage section 130.

[0206] An opening 144a is formed in the bottom plate 144. The opening 144a is formed below the measuring head 110. The opening 144a exposes the portion of the sample 101 facing the measuring head 110. The indenter 10 can contact the sample 101 through the opening 144a. During measurement, the lower surface of the bottom plate 144 contacts the upper surface of the sample 101.

[0207] [Effects of the hardness testing apparatus 100 according to the fourth embodiment] The hardness testing apparatus 100 according to the fourth embodiment does not include a sample stage 104. According to the hardness testing apparatus 100 according to the fourth embodiment, the contact position between the indenter 10 and the sample 101 can be detected using a simple device without providing a sample stage 104 under the sample 101. The hardness testing apparatus 100 according to the fourth embodiment can measure the hardness of a sample 101 that is larger than the hardness testing apparatus 100. Furthermore, by not including a sample stage 104, the hardness testing apparatus 100 can be made more compact.

[0208] [Hardness testing system 250 based on propagation] Figure 16 is a block diagram showing the configuration of a hardness testing system 250 according to an embodiment. The hardness testing system 250 according to an embodiment includes a hardness testing device 100 for measuring the hardness of a sample, and a processing device (e.g., an external processing PC) 260 for processing signals acquired from the hardness testing device 100.

[0209] The hardness testing apparatus 100 comprises an indenter 10 that is pressed into the sample, a support shaft 20 that supports the indenter 10 and is movable in the axial direction, a support mechanism 30 that supports the support shaft 20, an actuator 40 that moves the support shaft 20 in the axial direction, and a displacement detection unit 50 that detects the displacement of the indenter 10 in the axial direction.

[0210] The processing unit 260 includes a signal processing unit 280 that processes a displacement signal related to the displacement of the indenter 10 detected by the displacement detection unit 50, and a load signal related to the load acting on the indenter 10, and a control unit 270 that controls the operation of the indenter 10.

[0211] Before performing the actual measurement to measure the hardness of the sample 101, the control unit 270 causes the indenter 10 to perform a free-running operation, moving it in the indentation direction so that it passes over a virtual surface 103, which is the position where the surface (contact surface) 102 of the sample 101 is located, without making contact with the sample 101. The control unit 270 may be the control unit 70 described above.

[0212] The signal processing function 221 shown in Figure 6 acquires data on the displacement of the indenter 10 during the idle motion and data on the load acting on the indenter 10. Based on the data on the displacement of the indenter 10 in this measurement, the data on the load acting on the indenter 10 in this measurement, the data on the displacement of the indenter 10 during the idle motion, and the data on the load acting on the indenter during the idle motion, the hardness of the sample is measured.

[0213] [Hardness testing apparatus 100 related to a modified example] A modified hardness testing apparatus 100 may include a processing unit (CPU 211) that performs the processing performed in the processing apparatus (see Figure 16) 260 described above.

[0214] [Examples of materials that can be measured using the hardness testing apparatus 100 according to the embodiment] Next, with reference to Figure 18, an example of a material (sample 101) that can be measured using the hardness testing apparatus 100 according to the embodiment will be described. Figure 18 is a table showing an example of a material that can be measured using the hardness testing apparatus 100 according to the embodiment. Figure 18 shows an example of a material that can be measured using a general hardness tester. Examples of general hardness testers include durometers, durometer-Barcol, Martens hardness testers, Rockwell hardness testers, and Vickers hardness testers.

[0215] In Figure 18, softer materials are shown on the left, and harder materials are shown on the right. Materials listed on the left are softer, and materials listed on the right are harder.

[0216] Materials that can be measured by the hardness testing device 100 include, for example, general-purpose solid rubber, PVC (polyvinyl chloride), PE (polyethylene), hard plastics, ebonite, PP (polypropylene), PET (polyethylene terephthalate), FRP (fiber-reinforced plastics), and metals. Materials that can be measured by the hardness testing device 100 also include, for example, soft metals such as lead, tin, zinc, and silver. The range of materials that can be measured by the hardness testing device 100 is approximately the same as that of a Martens hardness tester.

[0217] Furthermore, specific examples of items that can be measured by the hardness testing device 100 include, for example, rubber rolls, automobile tires, rubber belts, O-rings, flooring materials, golf balls, coatings, resin packaging materials, printed circuit boards, and bathtubs.

[0218] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

[0219] One aspect of the present invention may be as follows: <1> A control process in which the control unit controls the movement of the indenter, A reference measurement step involves performing a free-running operation in which the indenter is moved in the pressing direction so as to pass a virtual surface where the contact surface of the sample is located, without the indenter coming into contact with the sample, and acquiring data on the displacement of the indenter and data on the load of the indenter. This measurement step involves bringing the indenter into contact with the sample to obtain data regarding the displacement of the indenter and data regarding the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step A hardness test method comprising the step of a control unit measuring the hardness of the sample using a device. <2> The process of reading the maximum load value and the pressing time, which are the set conditions in the above measurement process, Executed by the signal processing unit, Data relating to the displacement of the indenter obtained in the aforementioned reference measurement step, The load data acting on the indenter obtained in the aforementioned reference measurement step, The data relating to the displacement of the indenter obtained in the above measurement process, and By comparing the load data acting on the indenter obtained in the above measurement process, A contact point detection step for detecting the contact point which is the position where contact between the indenter and the sample begins, Includes, The maximum load value of the measurement step described above is The contact point detected in the above contact point detection step is set as the zero point where the application of the load begins. In order to apply the load to the indenter and move the indenter until the maximum load value is reached, Used in the drive load value calculation step for calculating the drive load value to be applied to the indenter, The pressing time in the above measurement step is The contact point detected in the contact point detection step is set as the zero point for starting the measurement of the pressing time, and the elapsed time until the driving load value is reached is the time elapsed until the driving load value is reached. In the aforementioned measurement process, while executing the contact point detection process and the drive load value calculation process, In the above measurement step, the drive load value is reached in the aforementioned pressing time at a predetermined speed The indenter is pressed into the sample. <1> The hardness test method described in [reference]. <3> The above-mentioned drive load value calculation step is: Executed by the aforementioned signal processing unit, The process includes calculating a first function that shows a function of the displacement signal related to the displacement of the indenter during the free-running operation and the load signal based on data related to the load of the indenter, In the above drive load value calculation step, The signal processing unit calculates the drive load value using the first function, During the execution of the above measurement process, the drive load value is determined using the first function. <2> The hardness test method described in [reference]. <4> Executed by the aforementioned signal processing unit, The process includes calculating a second function that shows the relationship between a displacement signal based on data relating to the displacement of the indenter obtained in the measurement process and a load signal based on data relating to the load of the indenter. In the aforementioned contact point detection step, The signal processing unit compares the first function and the second function, The contact point, which is the point at which contact between the indenter and the sample begins, is detected. The aforementioned drive load value is calculated, In the measurement process described above, after detecting the contact point, the drive load value corresponding to the maximum load value is determined. The above is applied to the indenter to press down on the indenter. <3> The hardness test method described in [reference]. <5> The aforementioned contact point detection step is: Executed by the aforementioned signal processing unit, At the same displacement of the indenter, the difference value, which is the difference between the first load value in the first function and the second load value in the second function, is calculated. The position of the indenter when the difference value exceeds a first determination threshold for detecting the contact point is detected as the contact point. <4> The hardness test method described in [reference]. <6> In the aforementioned contact point detection step, Executed by the aforementioned signal processing unit, The first rate of change is the slope of the first function, During the execution of the above measurement process, the second rate of change, which is the slope of the second function per unit time, Calculate, The position of the indenter when the second rate of change exceeds a second determination threshold for detecting the contact point is detected as the contact point. <4> The hardness test method described in [reference]. <7> The aforementioned contact point detection step is: The signal processing unit performs a step of calculating a third function that shows the relationship between the displacement signal and the load signal obtained in the measurement step, before the sample and the indenter come into contact. A step performed by the signal processing unit to calculate a fourth function that shows the relationship between the displacement signal and the load signal after the sample and the indenter come into contact, which was acquired in the measurement step, The process includes the step of calculating a fifth function by fitting a curve connecting a straight line based on the third function and a straight line based on the fourth function using the least squares method, which is performed by the signal processing unit, The above fifth function is used to detect the contact point, <4> The hardness test method described in [reference]. <8> The indenter is pressed into the sample, A support shaft that supports the indenter and is movable in the axial direction, A support mechanism that supports the aforementioned support shaft, An actuator that moves the support shaft in the axial direction, The system includes a displacement detection unit for detecting the displacement of the indenter in the axial direction, A reference measurement step involves performing a free-running operation in which the indenter is moved in the pressing direction so as to pass a virtual surface where the contact surface of the sample is located, without the indenter coming into contact with the sample, and acquiring data on the displacement of the indenter and data on the load of the indenter. This measurement step involves bringing the indenter into contact with the sample to obtain data regarding the displacement of the indenter and data regarding the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step A hardness testing apparatus capable of performing the steps of: a control unit measuring the hardness of the sample using [a specific method / tool]. <9> A hardness testing system comprising a hardness testing device for measuring the hardness of a sample, and a processing device for processing signals acquired from the hardness testing device, The hardness testing apparatus described above is The indenter is pressed into the sample, A support shaft that supports the indenter and is movable in the axial direction, A support mechanism that supports the aforementioned support shaft, An actuator that moves the support shaft in the axial direction, The system includes a displacement detection unit for detecting the displacement of the indenter in the axial direction, The aforementioned processing apparatus is A signal processing unit that processes a displacement signal relating to the displacement of the indenter detected by the displacement detection unit, and a load signal relating to the load acting on the indenter, A hardness testing system including a control unit for controlling the operation of the indenter. The control unit Performs an idle running operation of moving the indenter in the pressing direction so as to pass through a virtual surface which is the position where the contact surface of the sample is arranged, without contacting the indenter with the sample, and obtains data regarding the displacement of the indenter and data regarding the load of the indenter, which is a reference measurement step. Contacts the indenter with the sample and obtains data regarding the displacement of the indenter and data regarding the load of the indenter, which is a main measurement step. Data regarding the displacement of the indenter in the main measurement step Data regarding the load acting on the indenter in the main measurement step Data regarding the displacement of the indenter in the reference measurement step, and Data regarding the load acting on the indenter in the reference measurement step Using these, a step in which the control unit measures the hardness of the sample can be executed.

Description of Signs

[0220] 100: Hardness testing device, 10: Indenter, 20: Support shaft, 30: Support mechanism, 40: Actuator, 50: Displacement detection unit, 70: Control unit, 101: Sample, 102: Surface (contact surface), 103: Virtual surface, 250: Hardness testing system, 260: External processing PC, 270: Control unit, 280: Signal processing unit Z: Z-axis direction (axial direction, pressing direction).

Claims

1. A control process in which the control unit controls the movement of the indenter, A reference measurement step in which the indenter is moved in the pressing direction in a free-running operation over a first section to a virtual surface where the contact surface of the sample is located, and a second section following the virtual surface, without the indenter coming into contact with the sample, and data regarding the displacement of the indenter and data regarding the load of the indenter are obtained. This measurement process involves moving the indenter in the pressing direction over a first section until the indenter is brought into contact with the sample, and a second section where the indenter is in contact with the sample, while acquiring data on the displacement of the indenter and data on the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step A hardness test method comprising the step of a control unit measuring the hardness of the sample using a device.

2. The process of reading the maximum load value and the pressing time, which are the set conditions in the above measurement process, Executed by the signal processing unit, Data relating to the displacement of the indenter obtained in the aforementioned reference measurement step, The load data acting on the indenter obtained in the aforementioned reference measurement step, The data relating to the displacement of the indenter obtained in the above measurement process, and By comparing the load data acting on the indenter obtained in the above measurement process, A contact point detection step for detecting the contact point which is the position where contact between the indenter and the sample begins, Includes, The maximum load value of the measurement step described above is The contact point detected in the above contact point detection step is set as the zero point where the application of the load begins. In order to apply the load to the indenter and move the indenter until the maximum load value is reached, Used in the drive load value calculation step for calculating the drive load value to be applied to the indenter, The pressing time in the above measurement step is The contact point detected in the contact point detection step is set as the zero point for starting the measurement of the pressing time, and the elapsed time until the driving load value is reached is the time elapsed until the driving load value is reached. In the aforementioned measurement process, while executing the contact point detection process and the drive load value calculation process, In the above measurement step, the drive load value is reached in the aforementioned pressing time at a predetermined speed The hardness test method according to claim 1, wherein the indenter is pressed into the sample.

3. The above-mentioned drive load value calculation step is: Executed by the aforementioned signal processing unit, The process includes calculating a first function that shows a function of the displacement signal related to the displacement of the indenter during the free-running operation and the load signal based on data related to the load of the indenter, In the above drive load value calculation step, The signal processing unit calculates the drive load value using the first function, The hardness test method according to claim 2, wherein the driving load value is determined using the first function during the execution of the measurement step described above.

4. Executed by the aforementioned signal processing unit, The process includes a step of calculating a second function that shows the relationship between a displacement signal based on data relating to the displacement of the indenter obtained in the measurement step and a load signal based on data relating to the load of the indenter, In the aforementioned contact point detection step, The signal processing unit compares the first function and the second function, The contact point, which is the point at which contact between the indenter and the sample begins, is detected. The aforementioned drive load value is calculated, In the measurement process described above, after detecting the contact point, the drive load value corresponding to the maximum load value is determined. The hardness test method according to claim 3, wherein the indenter is pressed down by applying the indenter.

5. The aforementioned contact point detection step is: Executed by the aforementioned signal processing unit, At the same displacement of the indenter, the difference value, which is the difference between the first load value in the first function and the second load value in the second function, is calculated. The hardness test method according to claim 4, wherein the position of the indenter when the difference value exceeds a first determination threshold for detecting the contact point is detected as the contact point.

6. In the aforementioned contact point detection step, Executed by the aforementioned signal processing unit, The first rate of change is the slope of the first function, During the execution of the above measurement process, the second rate of change, which is the slope of the second function per unit time, Calculate, The hardness test method according to claim 4, wherein the position of the indenter when the second rate of change exceeds a second determination threshold for detecting the contact point is detected as the contact point.

7. The aforementioned contact point detection step is: A step performed by the signal processing unit to calculate a third function that shows the relationship between the displacement signal and the load signal obtained in the measurement step before the sample and the indenter come into contact, A step performed by the signal processing unit to calculate a fourth function that shows the relationship between the displacement signal and the load signal after the sample and the indenter come into contact, which was acquired in the measurement step, The process includes the step of calculating a fifth function by fitting a curve connecting a straight line based on the third function and a straight line based on the fourth function using the least squares method, which is performed by the signal processing unit, The hardness test method according to claim 4, wherein the contact point is detected using the fifth function.

8. The indenter is pressed into the sample, A support shaft that supports the indenter and is movable in the axial direction, A support mechanism that supports the aforementioned support shaft, An actuator that moves the support shaft in the axial direction, The system includes a displacement detection unit for detecting the displacement of the indenter in the axial direction, A reference measurement step in which the indenter is moved in the pressing direction in a free-running operation over a first section to a virtual surface where the contact surface of the sample is located, and a second section following the virtual surface, without the indenter coming into contact with the sample, and data regarding the displacement of the indenter and data regarding the load of the indenter are obtained. This measurement process involves moving the indenter in the pressing direction over a first section until the indenter is brought into contact with the sample, and a second section where the indenter is in contact with the sample, while acquiring data on the displacement of the indenter and data on the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step A hardness testing apparatus capable of performing the steps of: a control unit measuring the hardness of the sample using [a specific method / tool].

9. A hardness testing system comprising a hardness testing device for measuring the hardness of a sample, and a processing device for processing signals acquired from the hardness testing device, The hardness testing apparatus described above is The indenter is pressed into the sample, A support shaft that supports the indenter and is movable in the axial direction, A support mechanism that supports the aforementioned support shaft, An actuator that moves the support shaft in the axial direction, The system includes a displacement detection unit for detecting the displacement of the indenter in the axial direction, The aforementioned processing apparatus is A signal processing unit that processes a displacement signal relating to the displacement of the indenter detected by the displacement detection unit, and a load signal relating to the load acting on the indenter, The system includes a control unit that controls the operation of the indenter, The control unit, A reference measurement step in which the indenter is moved in the pressing direction in a free-running operation over a first section to a virtual surface where the contact surface of the sample is located, and a second section following the virtual surface, without the indenter coming into contact with the sample, and data regarding the displacement of the indenter and data regarding the load of the indenter are obtained. This measurement process involves moving the indenter in the pressing direction over a first section until the indenter is brought into contact with the sample, and a second section where the indenter is in contact with the sample, while acquiring data on the displacement of the indenter and data on the load of the indenter. Data relating to the displacement of the indenter in the aforementioned measurement process, Data of the load acting on the indenter in the aforementioned measurement process, The data relating to the displacement of the indenter in the aforementioned reference measurement process, and Data of the load acting on the indenter in the aforementioned reference measurement step A hardness testing system capable of performing the steps of: a control unit measuring the hardness of the sample using [a specific method / tool].

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