JP7103086B2 - Material testing machine - Google Patents

Description

The present invention relates to a material tester provided with a measuring device for measuring the dimensions of test pieces in a material tester for continuously testing a large number of test pieces.

Some material testers that perform material tests are called automatic machines that continuously test a large number of test pieces. In such a material testing machine, if a plurality of test pieces are stored in a storage magazine, the test pieces can be taken out from the storage magazine, the test pieces are measured, the material test for the test pieces, the recovery of the test pieces, and the test. Data processing is continuously and automatically executed (see Patent Document 1).

The stress generated when a tensile or compressive test force is applied to the test piece is the test force acting on the test piece divided by the cross-sectional area of the test piece. The measurement of the test piece is a step of measuring the width and thickness of both end portions and the central portion between the reference points of the test piece with a measuring device in order to obtain the cross-sectional area of the test piece. The thickness of the test piece is measured by a gauge in which a pair of arms supporting each measuring indenter are brought close to each other by driving a motor, and the test piece is sandwiched by a pair of measuring indenters (Patent Document). 2).

Japanese Unexamined Patent Publication No. 9-229836 Japanese Unexamined Patent Publication No. 2011-13061

Before measuring the dimensions of each test piece, a pair of measuring indenters are brought into contact with each other to perform zero point calibration of the gauge. Then, the output value of the gauge after the zero point calibration is the amount of change from the zero point. If zero point calibration is performed with foreign matter (for example, metal scraps during processing of the test piece) between the measuring indenters, the measurement data will be offset by the thickness of the foreign matter, and the thickness of the test piece will be offset. Cannot be measured accurately. In a material testing machine called an automatic machine, the operation of loading, measuring, and unloading the test piece into the measuring device is automatically performed, so the measuring indenter is in the middle of the material test that is continuously executed. Even if the zero point calibration is performed with foreign matter adhering to the sword and there is foreign matter between the pair of measuring indenters, the test continues as it is. The test data would then include stress data based on the cross-sectional area calculated with inaccurate dimensions, impairing the accuracy of the material test.

The present invention has been made to solve the above problems, and includes a measuring device capable of confirming the presence or absence of foreign matter between a pair of measuring indenters at the time of zero point calibration before measuring the test piece. It is an object of the present invention to provide a material testing machine.

The invention according to claim 1 is a material testing machine provided with a measuring device for measuring the dimensions of a test piece, wherein the measuring device includes a pair of measuring indenters in contact with the test piece and the pair of measuring indenters. The test piece was sandwiched by the pair of measuring indenters, which were connected to one of the pair of arms, the pair of arms supporting the indenter, the driving mechanism for moving the pair of arms close to each other, and the pair of arms. The control is provided with a detector for detecting the thickness of the test piece and a control unit for calibrating the output value of the detector when the pair of measuring indenters are brought into contact with each other. The unit has a determination unit for determining whether or not there is a deviation between the output value of the detector and the zero point at that time when the pair of measuring indenters are brought into contact with each other before measuring the test piece. When the determination unit determines that there is a discrepancy between the output value of the detector and the zero point at that time, the measuring operation is terminated without calibrating the output value of the detector at the zero point. It is a feature.

The invention according to claim 2 is a control device that controls a testing machine main body having a load mechanism for applying a test force to the test piece and a transfer mechanism for transporting the test piece from the measuring device to the testing machine main body. The control unit of the measuring device includes the output value of the detector when the determination unit brings the pair of measuring indenters into contact with each other before measuring the test piece, and the output value at that time. When it is determined that there is a deviation from the zero point, a stop signal is transmitted to the control device, and the control device stops the transfer of the test piece by the transfer mechanism.

According to the invention of claim 1, the deviation between the output value of the detector and the zero point at that time when the measuring device brings a pair of measuring indenters into contact with each other before measuring the test piece. Since it is determined whether or not the test piece is present, it is possible to confirm the presence or absence of foreign matter between the pair of measuring indenters before executing the zero point calibration before measuring the test piece. Then, from the determination result by the determination unit, the user can easily know the state in which the foreign matter has entered between the measuring indenters. If there is a discrepancy between the output value of the detector when a pair of measuring indenters are brought into contact with each other before measuring the test piece and the zero point at that time, the measurement is performed without performing zero point calibration. Since the operation is terminated, it is possible to prevent a large offset from being applied to the measurement data. This makes it possible to prevent an abnormality in the test result due to an abnormality in the measurement data.

According to the invention of claim 2, the output value of the detector when the determination unit of the measuring device brings a pair of measuring indenters into contact with each other before measuring the test piece, and the zero point at that time. If it is determined that there is a discrepancy between the two, it is suspected that foreign matter has entered between the measuring indenters, so a stop signal is sent to the control device, and the control device stops the transfer of the test piece by the transfer mechanism. Therefore, it is possible to stop the automatic operation of the material testing machine and prevent an abnormal test result from being output. Further, by stopping the automatic operation, it is possible to reduce the waste of the test piece and the waste of the test time.

It is a schematic diagram of the material testing machine which concerns on this invention. It is a block diagram which shows the main electrical composition of the material tester provided with the measuring apparatus 3. It is a perspective view which looked at the measuring apparatus 3 from the diagonally upper right direction. It is sectional drawing of the periphery of the measuring grip 41 in the measuring device 3. It is a flowchart explaining the measuring operation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a material testing machine according to the present invention. FIG. 2 is a block diagram showing a main electrical configuration of a material testing machine equipped with a measuring device 3.

This material testing machine includes a storage magazine 2 for stacking and accommodating a plurality of test piece TPs, a measuring device 3 for measuring the thickness of the test piece TP, and a testing machine main body 1 for executing a tensile test. In this material testing machine, the test piece TP is taken out one by one from the storage magazine 2 by the action of the transport mechanism 4 (see FIG. 2) such as a robot arm, and the test piece is placed at the test position of the testing machine main body 1 through the measuring device 3. By arranging TPs and executing the test, a continuous tensile test is automatically performed on a plurality of test piece TPs.

A pair of frames 12 are erected on the base 18 of the testing machine main body 1, and a pair of screw rods that are synchronously rotated by a drive mechanism 25 (see FIG. 2) are arranged in the frame 12. ing. A nut internally provided in the crosshead 11 is screwed into the screw rod, and the crosshead 11 moves up and down by the rotation of the screw rod. The ascending / descending operation of the crosshead 11 is controlled by the control device 17 connected to the testing machine main body 1.

In the testing machine main body 1, the upper gripping tool 14 is connected to the crosshead 11 via a load cell 16 that detects a test force, and the lower gripping tool 15 is arranged on the base 18, and the upper gripping tool 14 and the upper gripping tool 14 are arranged. A tensile test is performed by raising the crosshead 11 with respect to the test piece TP whose both ends are gripped by the lower gripper 15. A video camera 19 for measuring the elongation of the test piece TP is arranged on the frame 12.

In the transport of the test piece TP from the storage magazine 2 of the test piece TP to the gripping position (test position) of the test piece TP by the upper gripping tool 14 and the lower gripping tool 15 of the testing machine main body 1, for example, the test piece TP is sucked and held by the suction pad. This is performed by a transport mechanism 4 such as a transport arm or a belt conveyor. The operation of the transport mechanism 4 is controlled by the control device 17.

The control device 17 measures the dimensions of the test piece TP, the transport mechanism 4 that conveys the test piece TP from the drive mechanism 25 of the tester main body 1 and the storage magazine 2 to the tester main body 1 via the measuring device 3. The device 3 is connected to a removal device 5 for removing the tested test piece TP from the upper grip 14 and the lower grip 15, and controls an automatic test in which a large number of test piece TPs are continuously tested. The control device 17 is connected to a memory 71 such as a ROM or RAM, an arithmetic unit 76 such as an MPU or a CPU, a storage device 77 for storing data such as test results, and an external connection such as a measuring device 3 according to a predetermined communication protocol. It is provided with a communication unit 75 that communicates with the device. The memory 71, the communication unit 75, the arithmetic unit 76, and the storage device 77 are connected to each other via the bus 79. In FIG. 2, the program stored in the memory 71 is shown as a functional block. The memory 71 includes an image processing unit 72 that processes an image acquired from the video camera 19, a test control unit 73 that executes a material test by generating a controlled amount of a drive mechanism 25 that raises and lowers the crosshead 11, and a test. A transport control unit 74 that controls a transport mechanism 4 that transports one TP is provided.

When the test piece TP is gripped by the upper gripping tool 14 and the lower gripping tool 15, the crosshead 11 is raised by the control of the control device 17 in the testing machine main body 1, and a tensile load is applied to the test piece TP. The drive mechanism 25 that moves the crosshead 11 functions as the load mechanism of the present invention. The test force at that time is detected by the load cell 16 arranged on the crosshead 11, and the detection signal is sent to the control device 17. The image acquired by the video camera 19 is input to the control device 17, and the elongation of the test piece TP obtained by the image processing is displayed on the input display unit 21. The input display unit 21 is a liquid crystal display device provided with a touch panel, and also functions as an input device operated when a user inputs test conditions.

When the test piece TP breaks, the crosshead 11 stops ascending under the control of the control device 17, and the tensile test ends. After that, the broken test piece TP that remains gripped by the upper gripping tool 14 and the lower gripping tool 15 is removed from the upper gripping tool 14 and the lower gripping tool 15 by the removing device 5.

FIG. 3 is a perspective view of the measuring device 3 as viewed from diagonally upward to the right. In FIG. 3, a configuration for measuring the thickness of the test piece TP is shown in particular. FIG. 4 is a cross-sectional schematic view of the periphery of the measuring grip 41 in the measuring device 3.

The measuring device 3 includes a pair of measuring grips 41 that grip the test piece TP to measure the thickness of the test piece TP, and an upper arm 32 and a lower arm 33 that support the pair of measuring indenters 31, respectively. It has the above-mentioned configuration. The pair of measuring grips 41 are connected to the air cylinders 36 and 37. A gauge 34 used for measuring the thickness of the test piece TP is attached to the upper arm 32. Further, an air cylinder 35 for sandwiching the test piece TP by a pair of measuring indenters 31 is connected to the lower arm 33 by raising the lower arm 33. The pair of measuring grips 41 are provided with holes through which the pair of measuring indenters 31 supported by the upper arm 32 and the lower arm 33 penetrate, and the tip of the measuring indenter 31 on the upper arm 32 side is an upper measuring indenter. It is arranged so as to be at the same position as the test piece contact surface of the dimension grip 41. The tip of the measuring indenter 31 on the lower arm side moves up and down through the hole of the measuring grip 41 on the lower side by moving the lower arm 33 up and down by the operation of the air cylinder 35. When the test piece TP is sandwiched by the pair of measuring indenters 31, the lower arm 33 is raised by the operation of the air cylinder 35 after the test piece TP is lightly grasped by the pair of measuring grips 41 by the operation of the air cylinders 36 and 37. Then, the pair of measuring indenters 31 are pressed against the test piece TP.

The gauge 34 is a linear gauge including a sensor for detecting the displacement amount of the spindle and a digital counter, and measures the displacement amount by bringing a stylus at the tip of the spindle into contact with an object to be measured. This gauge 34 tests the amount of displacement from the zero point when the pair of measuring indenters 31 abuts on the test piece TP by calibrating the zero point with the pair of measuring indenters 31 in contact with each other. It functions as a thickness detector that measures the thickness of one TP. The measuring indenter 31 of the upper arm 32 may also serve as the stylus of the gauge 34, and the stylus is brought into contact with the test piece TP at a position different from the pair of measuring indenters 31 to measure the thickness. You may. Further, in this embodiment, the gauge 34 is connected to the upper arm 32 side, but it may be connected to either the upper arm 32 or the lower arm 33.

Again, referring to FIG. 2, the measuring device 3 is a control unit having a memory 81 such as a ROM and a RAM, an arithmetic unit 86 such as an MPU or a CPU, and a communication unit 85 that performs data communication with the control device 17. Equipped with 80. The memory 81, the arithmetic unit 86, and the communication unit 85 are connected to each other by a bus 89. The measuring device 3 is connected to the control device 17, and the measured dimensions of each test piece TP are transmitted to the control device 17 via the communication unit 85. The control unit 80 is connected to the gauge 34 and the air cylinder 35. In FIG. 2, a program stored in the memory 81 and executed by the arithmetic unit 86 is shown as a functional block. As a functional block, the memory 81 determines whether or not there is a deviation between the output value of the gauge 34 and the zero point at that time when the pair of measuring indenters 31 are brought into contact with each other before measuring the test piece TP. A unit 82 and a motor control unit 83 that controls the operation of the air cylinder 35 are provided.

Next, the operation of measuring the test piece TP by the measuring device 3 configured as described above will be described. FIG. 5 is a flowchart illustrating a measuring operation. The flowchart shown in FIG. 5 shows an operation when measuring one test piece TP.

When an automatic test for continuously testing a plurality of test piece TPs is started, the measuring device 3 is placed between a pair of measuring indenters 31 that are brought into contact with the test pieces TP in order to measure the thickness of each test piece TP. The step of confirming the presence or absence of foreign matter is executed. First, the lower arm 33 is brought close to the upper arm 32 by driving the air cylinder 35, so that the pair of measuring indenters 31 are brought into contact with each other (step S1). The output value of the gauge 34 when the pair of measuring indenters 31 are brought into contact with each other is input to the control unit 80, and the zero point when the previous zero point was calibrated by the function of the determination unit 82, that is, the current zero. The presence or absence of deviation from the point (presence or absence of foreign matter between the pair of measuring indenters 31) is determined (step S2). Before the start of the automatic test, it is assumed that the user wipes the measuring indenter 31 with a soft cloth or the like in advance to remove foreign substances and the like, and the measurement is performed on the first test piece TP. It is assumed that zero point calibration has been performed at least once before starting operation.

The presence or absence of foreign matter is determined based on the presence or absence of this deviation by setting a threshold value for the zero point and checking whether or not the output value of the gauge 34 exceeds the threshold value. Here, as the threshold value, since the measurement data in the state where the foreign matter is sandwiched between the measuring indenters 31 is empirically several μm to several tens of μm, the measurement is performed according to the material and processing condition of the test piece TP. A value that can be tolerated as an error, for example, a value such as 1 μm on the minus side and 5 μm on the plus side is set. If the deviation (difference) between the output value of the gauge 34 and the zero point at that time exceeds the threshold value, it is suspected that a foreign substance is caught between the measuring indenters 31, and it is determined that there is a foreign substance. (Step S2). Then, the control unit 80 separates the lower arm 33 from the upper arm 32 by driving the air cylinder 35, separates the pair of measuring indenters 31, and transmits a test stop signal to the control device 17 (step S7). , End the measuring operation.

Upon receiving the test stop signal, the control device 17 stops the transfer of the test piece TP by the transfer mechanism 4 and stops the automatic test. After that, the control device 17 gives a warning to notify the user that the test is stopped, if necessary. The warning may be a warning text or an error content display on the input display unit 21, or may be a sound warning. Before resuming the test, the user wipes the measuring indenter 31 with a soft cloth or the like to remove foreign matter. After that, restart the test.

Before carrying the test piece TP into the measuring device 3, the pair of measuring indenters 31 are brought into contact with each other (step S1), and it is determined that there is no deviation between the output value of the gauge 34 and the zero point at that time and there is no foreign matter. If (step S2), the control unit 80 executes zero point calibration at the contacted position (step S3). In the zero point calibration, the value detected in step S2 is set to zero, and the zero point is updated. That is, the value of the digital counter of the gauge 34 at that time is set to zero. After that, the test piece TP is carried from the storage magazine 2 to the measuring device 3 by the transport mechanism 4 (step S4), and the measuring is executed (step S5). In the measurement, the thickness of a plurality of points is measured by moving the position where the test piece TP is gripped by the measuring grip 41 in the horizontal direction. After that, it is carried out from the measuring device 3 to the testing machine main body 1 (step S6), and the measuring of the test piece TP is completed. The measurement data of each test piece TP is transmitted to the control device 17 via the communication unit 85, stored in the storage device 77 as a part of the test data, and stress during the tensile test in the testing machine main body 1. Used in the calculation of.

In a material testing machine called an automatic machine, from the viewpoint of maintaining the accuracy of the test, it is common to perform zero point calibration individually before measuring all the test piece TPs. In the embodiment, the determination unit 82 determines the presence or absence of foreign matter before the zero point calibration. However, depending on the material, the determination unit 82 may determine the presence or absence of foreign matter at a frequency of one in several.

In a material testing machine called a conventional automatic machine, the user cannot notice that foreign matter has entered between a pair of measuring indenters 31 during zero point calibration, and the tension of a plurality of test pieces TP is pulled. The test data sometimes became an abnormal value from the middle. In the present invention, as a function of the measuring device 3, it is checked whether the output value of the gauge 34 is significantly different from the zero point at that time before the zero point calibration. Therefore, the pair of measuring indenters 31 are used. The user can easily notice that foreign matter has entered between them, and can promptly take measures to maintain the accuracy of the measurement data used for stress calculation. In this embodiment, since the automatic test is not continued while the abnormality is detected, it is possible to reduce the waste of the test piece TP and the waste of the test time.

Further, in the above-described embodiment, the configuration of the testing machine main body 1 corresponds to the tensile test, but the present invention is not limited to this. The present invention can be applied to an automatic machine that executes other tests, such as a material testing machine that continuously executes a bending test on a plurality of test pieces TP.

1 Testing machine body 2 Storage magazine 3 Measuring device 4 Conveying mechanism 5 Detaching device 11 Crosshead 12 Frame 14 Upper gripper 15 Lower gripper 16 Load cell 17 Control device 18 Base 19 Video camera 21 Input display 25 Drive mechanism 31 Measurement Indenter 32 Upper arm 33 Lower arm 34 Gauge 35 Air cylinder 36 Air cylinder 37 Air cylinder 41 Measuring grip 71 Memory 72 Image processing unit 73 Test control unit 74 Transport control unit 75 Communication unit 76 Arithmetic unit 77 Storage device 80 Control unit 81 Memory 82 Judgment unit 83 Motor control unit 85 Communication unit 86 Arithmetic logic unit TP test piece

Claims (2)

In a material tester equipped with a measuring device that measures the dimensions of a test piece,
The measuring device is
A pair of measuring indenters that come into contact with the test piece,
A pair of arms that support each of the pair of measuring indenters,
A drive mechanism that brings the pair of arms close to each other and apart from each other,
A detector connected to one of the pair of arms and detecting the dimension of the test piece when the test piece is sandwiched by the pair of measuring indenters.
A control unit that controls a measuring operation for measuring the dimensions of the test piece and a zero point calibration operation for updating the zero point of the detector.
A storage unit that stores the updated zero point in the zero point calibration operation,
With
The control unit
Is there a deviation exceeding a predetermined threshold value between the output value of the detector when the pair of measuring indenters are brought into contact with each other before the measuring operation and the zero point stored in the storage unit? Judge whether or not
When it is determined that there is no deviation, the output value of the detector is set to zero, the operation of updating the zero point of the detector is performed as the zero point calibration operation, and then the measurement operation is performed.
A material testing machine characterized in that when it is determined that there is a deviation, the measuring operation is completed without performing the zero point calibration operation . A testing machine body having a load mechanism that gives a test force to the test piece, and
A transport mechanism that transports the test piece from the measuring device to the testing machine body, and
A control device for controlling the testing machine main body and the transport mechanism is further provided .
Claim 1 is characterized in that , when the control unit determines that there is a deviation, a stop signal is transmitted to the control device, and the control device receives the stop signal to stop the transport. Material testing machine described in .

Images