CN110879171B - Material testing machine - Google Patents

Abstract

Provided is a material testing machine including a dimensioning device capable of confirming the presence or absence of foreign matter between a pair of dimensioning indenters at the time of zero point calibration before dimension measurement of a test piece. The dimensioning device includes a control unit including a memory, an arithmetic unit, and a communication unit. The size of each test piece measured by the size measuring device is transmitted to the control device via the communication unit. The memory includes, as a functional block, a determination unit that determines whether or not there is a deviation between the zero point at the time of the previous zero point calibration and the output value of the gauge when a pair of dimension measuring indenters are brought into contact with each other before the size of the test piece is measured . If it is determined by the function of the determination unit that there is a deviation from the previous zero point, it is suspected that a foreign object is caught between the dimensioning indenters, and the control unit sends a stop command of the test to the control device to end the dimensioning operation.

Description

Material testing machine

technical field

It relates to a material testing machine including a dimension measuring device for measuring the size of a test piece, among material testing machines that continuously test a large number of test pieces.

Background technique

Among material testing machines that perform material testing, there is a material testing machine called an automatic machine that continuously tests a large number of test pieces. In such a material testing machine, as long as a plurality of test pieces are stored in the storage box, taking out the test pieces from the storage box, measuring the size of the test piece, testing the material of the test piece, and testing the test piece can be automatically and successively performed. Collection and processing of test data (refer to Patent Document 1).

The stress generated when a tensile or compressive test force is applied to the test piece is obtained by dividing the test force for the test piece by the cross-sectional area of the test piece. The dimensional measurement of the test piece is a step of measuring the width and thickness of both ends and the central part between the punctuation points of the test piece with a dimensional measuring device in order to obtain the cross-sectional area of the test piece. The following structure was adopted: the pair of arms supporting the dimensioning indenters were brought close to each other by the drive of the motor, the test piece was clamped by the pair of dimensioning indenters, and the thickness of the test piece was measured by the gauge (refer to Patent Literature ). 2).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 9-229836

Patent Document 2: Japanese Patent Laid-Open No. 2011-13061

SUMMARY OF THE INVENTION

Invention to solve problem

Before the size measurement of each test piece, a pair of size measurement indenters were brought into contact with each other to perform zero point calibration of the gauge. Then, the output value of the gauge after zero point correction is the amount of change with respect to the zero point. If the zero point calibration is performed in a state where foreign matter (for example, metal chips during test piece processing) has entered between the dimensioning indenters, the dimensioning data will deviate by an amount corresponding to the thickness of the foreign matter, making it inaccurate. The thickness of the test piece was measured. In a material testing machine called an automatic machine, the loading of the test piece into the dimensional measuring device, the dimensional measurement of the test piece in the dimensional measuring device, and the unloading of the test piece from the dimensional measuring device are performed automatically. In the middle of the material test performed continuously, a foreign matter adhered to the dimensioning indenter, and the zero-point calibration was performed in a state where the foreign matter was present between the pair of dimensioning indenters, and the test was continued. As a result, stress data based on cross-sectional areas calculated with inaccurate dimensions can be included in the test data, compromising the accuracy of material testing.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a material testing machine provided with a sizing device capable of confirming whether or not foreign matter exists between a pair of sizing indenters during zero point calibration before measuring the dimensions of a test piece .

solution to the problem

The invention described in the first invention is a material testing machine including a dimensioning device for measuring the dimensions of a test piece, the dimensioning device including a pair of dimensioning indenters, the pair of dimensioning indenters and the test piece contact; a pair of arms that respectively support the pair of dimensioning indenters; a drive mechanism that makes the pair of arms approach or move away from each other; a detector that is connected to the pair of arms Either one is connected to detect the thickness of the test piece when the test piece is sandwiched by the pair of dimensioning indenters; and a control unit that makes the pair of dimensioning indenters contact each other When the output value of the detector is zero, the zero point correction is performed, wherein the control unit has a determination unit that determines that the pair of dimension measuring indenters are to be mutually adjusted before measuring the size of the test piece. Whether there is a deviation between the output value of the detector at the time of contact and the zero point at this time, and when the determination unit determines that there is a deviation between the output value of the detector and the zero point at this time, the control unit The dimension measuring operation is terminated without performing zero point correction on the output value of the detector.

The invention described in the second invention further includes a control device for controlling a main body of a testing machine and a conveying mechanism, the main body of the testing machine having a load mechanism for applying a test force to the test piece, and the conveying mechanism moving the test piece from the test piece to the test piece. The dimensioning device is transported to the main body of the testing machine, and the determination unit determines that the output value of the detector when the pair of dimensioning indenters are brought into contact with each other before measuring the dimension of the test piece is the same as the output value of the detector. When there is a deviation between the zero points at this time, the control unit of the dimension measuring apparatus transmits a stop signal to the control apparatus, and the control apparatus stops the conveyance of the test piece by the conveyance mechanism.

effect of invention

According to the invention set forth in the first aspect of the invention, the dimension measuring device determines whether or not there is a deviation between the output value of the detector when the pair of dimension measuring indenters are brought into contact with each other before measuring the dimension of the test piece and the zero point at that time. Before performing the zero point calibration before the dimensioning of the test piece, it is confirmed whether or not foreign matter exists between the pair of dimensioning indenters. Furthermore, the user can easily know a state in which foreign matter has entered between the dimensioning indenters from the determination result of the determination unit. In addition, when there is a deviation between the output value of the detector when the pair of sizing indenters are brought into contact with each other before the size of the test piece is measured, and the zero point at that time, the sizing operation is terminated without performing zero point calibration, so that the dimension measurement can be prevented. The measured data has a large deviation. Thereby, it is possible to prevent abnormal test results due to abnormal dimensional measurement data.

According to the invention set forth in the second aspect of the invention, the output value of the detector when the pair of sizing indenters are brought into contact with each other before the measurement of the size of the test piece is judged by the judging unit of the sizing device is deviated from the zero point at that time. When it is suspected that a foreign object has entered between the dimensioning indenters, a stop signal is sent to the control device, and the control device stops the conveyance of the test piece by the conveying mechanism. Therefore, the automatic operation of the material testing machine can be stopped, and abnormal test results can be prevented from being output. in the future. In addition, by stopping the automatic operation, waste of test pieces and waste of test time can be reduced.

Description of drawings

FIG. 1 is a schematic diagram of a material testing machine according to the present invention.

FIG. 2 is a block diagram showing the main electrical configuration of the material testing machine provided with the dimension measuring device 3 .

FIG. 3 is a perspective view of the dimension measuring device 3 viewed obliquely from the upper right.

FIG. 4 is a schematic cross-sectional view of the periphery of the dimensioning clip 41 in the dimensioning device 3 .

FIG. 5 is a flowchart illustrating the size measurement operation.

Description of reference numerals

1: Testing machine body; 2: Storage; 3: Dimensioning device; 4: Conveying mechanism; 5: Demolition device; 11: Crosshead; 12: Frame; 14: Upper clamp; 15: Lower clamp; ;17: Control device; 18: Base; 19: Camera; 21: Input display part; 25: Drive mechanism; 31: Dimensioning indenter; 32: Upper arm; 33: Lower arm; ;36: air cylinder; 37: air cylinder; 41: dimensioning clip; 71: memory; 72: image processing unit; 73: test control unit; 74: conveyance control unit; 75: communication unit; device; 80: control unit; 81: memory; 82: determination unit; 83: motor control unit; 85: communication unit; 86: arithmetic device; TP: test piece.

Detailed ways

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

This material testing machine includes: a storage chamber 2 that houses a plurality of test pieces TP in layers; a dimension measuring device 3 that measures the thickness of the test pieces TP; and a testing machine main body 1 that performs a tensile test. This material testing machine takes out the test pieces TP one by one from the storage 2 by the action of the transport mechanism 4 (see FIG. 2 ) such as a robot arm, and arranges the test pieces TP at the test position of the testing machine main body 1 after passing through the dimension measuring device 3 . The test is performed, whereby the tensile test is automatically and continuously performed on the plurality of test pieces TP.

A pair of frames 12 are erected on the base 18 of the testing machine main body 1 , and a pair of screws synchronously rotated by a drive mechanism 25 (see FIG. 2 ) are arranged in the frames 12 . The screw is screwed with a nut provided in the cross head 11, and the cross head 11 is moved up and down by the rotation of the screw. The raising and lowering operation of the crosshead 11 is controlled by a control device 17 connected to the testing machine main body 1 .

In this testing machine main body 1, the crosshead 11 is connected to the upper jig 14 via the load cell 16 that detects the test force, the lower jig 15 is arranged on the base 18, and the upper jig 14 and the lower jig 15 are used. When holding both ends of the test piece TP, a tensile test is performed on the test piece TP by raising the crosshead 11 . Furthermore, the camera 19 for measuring the extension of the test piece TP is arranged on the frame 12 .

For example, the test piece TP is transported from the storage 2 by the transport mechanism 4 such as a transport arm or a belt conveyor to a holding position (test position) where the upper jig 14 and the lower jig 15 of the testing machine main body 1 grasp the test piece TP, wherein, The transport mechanism 4 adsorbs and holds the test piece TP by the adsorption pad. The operation of the conveying mechanism 4 is controlled by the control device 17 .

The control device 17 and the drive mechanism 25 of the testing machine main body 1, the conveying mechanism 4 that transfers the test piece TP from the storage 2 to the testing machine main body 1 via the dimension measuring device 3, the dimension measuring device 3 that measures the size of the test piece TP, the The test piece TP after the test is detached from the upper jig 14 and the lower jig 15, and the detachment device 5 is connected to control an automatic test in which a large number of test pieces TP are continuously tested. The control device 17 includes: a memory 71 such as a ROM and a RAM; an arithmetic device 76 such as an MPU or a CPU; a storage device 77 that stores data such as test results; communication between connected devices. The memory 71 , the communication unit 75 , the arithmetic device 76 , and the storage device 77 are connected to each other via a bus 79 . In FIG. 2, the programs stored in the memory 71 are represented as functional blocks. The memory 71 includes: an image processing unit 72 that processes an image acquired from the camera 19 ; a test control unit 73 that executes a material test by generating a control amount of the drive mechanism 25 for raising and lowering the crosshead 11 ; and a conveyance control unit 74, which controls the transport mechanism 4 that transports the test piece TP.

When the test piece TP is gripped by the upper jig 14 and the lower jig 15, in the testing machine main body 1, the crosshead 11 is raised by the control of the control device 17, and a tensile load is applied to the test piece TP. The drive mechanism 25 that moves the crosshead 11 functions as a load mechanism of the present invention. The test force at this time is detected by the load cell 16 disposed in the crosshead 11 , and the detection signal thereof is sent to the control device 17 . The image acquired by the camera 19 is input to the control device 17 , and the extension 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 including a touch panel, and also functions as an input device operated by the user when inputting test conditions.

When the test piece TP is broken, the rise of the crosshead 11 is stopped by the control of the control device 17, and the tensile test is completed. After that, the fractured test piece TP after the test originally held by the upper jig 14 and the lower jig 15 is detached from the upper jig 14 and the lower jig 15 by the detaching device 5 .

FIG. 3 is a perspective view of the dimension measuring device 3 viewed obliquely from the upper right. In FIG. 3, the structure for measuring the thickness of the test piece TP is shown especially. FIG. 4 is a schematic cross-sectional view of the periphery of the dimensioning clip 41 in the dimensioning device 3 .

The dimensioning apparatus 3 has a configuration in which a pair of dimensioning clips 41 for gripping the test piece TP for measuring the thickness of the test piece TP, and an upper arm 32 and a lower arm 33 respectively supporting the pair of dimensioning indenters 31 are provided. A pair of dimensioning clips 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 . In addition, an air cylinder 35 is connected to the lower arm 33 for raising the lower arm 33 so as to sandwich the test piece TP between the pair of dimensioning indenters 31 . The pair of dimensioning clips 41 is provided with a hole through which the pair of dimensioning indenters 31 supported by the upper arm 32 and the lower arm 33 penetrates, and the front end of the dimensioning indenter 31 on the upper arm 32 side is arranged so as to be in the dimension of the upper side. The position of the test piece contact surface of the measurement clip 41 is the same. The lower arm 33 is moved up and down by the operation of the air cylinder 35 , whereby the front end of the dimensioning ram 31 on the lower arm side moves up and down in the hole of the lower dimensioning clip 41 . When the pair of dimensioning indenters 31 is to clamp the test piece TP, the pair of dimensioning clamps 41 lightly grasp the test piece TP by the operation of the air cylinders 36 and 37 . The lower arm 33 is raised to press the pair of dimension measuring indenters 31 against the test piece TP.

The gauge 34 is a linear gauge including a sensor for detecting the displacement amount of the probe rod and a digital counter, and the displacement amount is measured by bringing the measuring element at the tip of the probe rod into contact with the object to be measured. The gauge 34 functions as a thickness detector that performs zero-point correction in a state where the pair of dimensioning indenters 31 are brought into contact with each other, thereby making the pair of dimensioning indenters 31 abut on the test piece TP. The amount of displacement with respect to the zero point was measured as the thickness of the test piece TP. In addition, the dimensioning indenter 31 of the upper arm 32 may also serve as a measuring piece of the gauge 34, and the thickness may be measured by contacting the measuring piece with the test piece TP at a position other than the pair of dimensioning indenters 31. In addition, in the present embodiment, the inspection tool 34 is connected to the upper arm 32 side, but it may be connected to any one of the upper arm 32 and the lower arm 33 .

Referring again to FIG. 2 , the dimensioning device 3 includes a control unit 80 including a memory 81 such as ROM and RAM, an arithmetic unit 86 such as an MPU or CPU, and a communication unit 85 that communicates data with the control unit 17 . The memory 81 , the arithmetic unit 86 , and the communication unit 85 are connected to each other by a bus 89 . The dimension 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 inspection tool 34 and the air cylinder 35 . In FIG. 2 , the programs stored in the memory 81 and executed by the arithmetic device 86 are represented as functional blocks. The memory 81 includes a determination unit 82 and a motor control unit 83 as functional blocks. The determination unit 82 determines the output value of the gauge 34 when the pair of dimension measuring indenters 31 are brought into contact with each other before measuring the size of the test piece TP, and the output value at that time. The motor control unit 83 controls the operation of the air cylinder 35 whether there is a deviation between the zero points.

Next, the operation of measuring the size of the test piece TP by the size measuring apparatus 3 configured as above will be described. FIG. 5 is a flowchart illustrating the size measurement operation. In addition, the flowchart shown in FIG. 5 shows the operation|movement at the time of measuring the dimension of one test piece TP.

When an automatic test for continuously testing a plurality of test pieces TP is started, the dimensioning device 3 performs a step of confirming a pair of dimensioning indenters that are in contact with the test pieces TP in order to measure the thickness of each test piece TP. Whether there is a foreign body between 31. First, by driving the air cylinder 35, the lower arm 33 is brought close to the upper arm 32, and the pair of dimensioning indenters 31 are brought into contact (step S1). The output value of the gauge 34 when the pair of dimensioning indenters 31 are brought into contact with each other is input to the control unit 80, and the function of the determination unit 82 determines whether it is between the zero point when the zero point calibration was performed last time, that is, the current zero point. There is a deviation (whether foreign matter exists between the pair of dimensioning indenters 31) (step S2). In addition, it is assumed that foreign matter etc. are removed by wiping the dimension measuring indenter 31 with a soft cloth or the like by the user before the start of the automatic test, and it is assumed that at least before the start of the first dimension measuring operation for the first test piece TP A zero point calibration.

A threshold value is set for the zero point, and whether or not there is a deviation is determined based on whether or not the output value of the gauge 34 exceeds the threshold value. Here, as the threshold value, the measurement data in the state where the foreign matter is sandwiched between the sizing indenters 31 is from several μm to several tens of μm according to experience. Therefore, it is set according to the material of the test piece TP and the processing state The allowable value for measurement error, for example, a value of 1 μm on the negative side and 5 μm on the positive side. If the deviation (difference) between the output value of the gauge 34 and the zero point at this time exceeds the threshold value, it is suspected that a foreign matter is caught between the dimensioning indenters 31, and it is determined that there is a foreign matter (step S2). Then, the control unit 80 drives the air cylinder 35 to move the lower arm 33 away from the upper arm 32, separates the pair of dimensioning indenters 31, and transmits a stop signal of the test to the control device 17 (step S7), thereby ending the dimensioning operation.

The control device 17 which received the stop signal of the test stops the conveyance of the test piece TP by the conveyance mechanism 4 . to stop the automatic test. After that, the control device 17 issues a warning to inform the user of the stop of the test as necessary. The warning may be a warning text or an error content displayed on the input display unit 21, or a warning may be given by sound. Before restarting the test, the user wipes the dimension measuring indenter 31 with a soft cloth or the like to remove foreign matter. After that, the experiment was restarted.

Before carrying the test piece TP into the dimensioning device 3, the pair of dimensioning indenters 31 are brought into contact (step S1), and if there is no deviation between the output value of the gauge 34 and the zero point at this time, it is determined that there is no foreign matter. (Step S2 ), the control unit 80 performs zero point correction at the contacted position (Step S3 ). In the zero point correction, the zero point is updated by setting the value detected in step S2 to zero. That is, the value of the digital counter of the gauge 34 at this time is set to zero. Then, the test piece TP is carried into the dimension measuring apparatus 3 from the storage 2 by the conveyance mechanism 4 (step S4), and dimension measurement is performed (step S5). In the dimension measurement, the thickness of a plurality of points is measured by moving the position where the test piece TP is gripped by the dimension measurement clip 41 in the horizontal direction. Then, it is carried out from the dimension measuring apparatus 3 to the testing machine main body 1 (step S6), and the dimension measurement of the test piece TP is complete|finished. The dimensional measurement data of each test piece TP is transmitted to the control device 17 via the communication unit 85, and is stored in the storage device 77 as a part of the test data. Dimensional data were used for stress calculations.

In a material testing machine called an automatic machine, from the viewpoint of maintaining the accuracy of the test, in general, zero point calibration is performed for all test pieces TP one by one before dimension measurement. Therefore, in this embodiment, the zero point is Before the calibration, the determination unit 82 determines whether or not there is a foreign matter. However, depending on the material, the determination of the presence or absence of foreign matter by the determination unit 82 may be performed at a frequency of taking one test piece TP for every several test pieces TP.

In a conventional material testing machine called an automatic machine, there are cases in which the user cannot notice that a foreign matter enters between the pair of dimensioning indenters 31 during zero point calibration, and the tensile test data of the plurality of test pieces TP are changed from A value that becomes abnormal halfway through. In the present invention, as a function of the dimension measuring device 3, before the zero point calibration, it is checked whether the output value of the gauge 34 does not greatly deviate from the zero point at that time, so the user can easily notice that a foreign object has entered a pair of dimension measuring pressures. Between the heads 31, it is possible to quickly take measures to maintain the accuracy of the dimensional measurement data used in the stress calculation. Furthermore, in the present embodiment, since the automatic test is not continued even after abnormality is detected, waste of the test piece TP and waste of the test time can be reduced.

In addition, in the above-mentioned embodiment, although the structure of the testing machine main body 1 is a structure which supports a tensile test, it is not limited to this. The present invention can be applied to an automatic machine that performs other tests, such as a material testing machine that continuously performs a bending test on a plurality of test pieces TP.

Claims (2)

1. A material testing machine having a dimension measuring device for measuring a dimension of a test piece, the material testing machine being characterized in that,

the size measuring device comprises:

a pair of sizing indenters in contact with the test strip;

a pair of arms that support the pair of sizing indenters, respectively;

a drive mechanism that moves the pair of arms toward and away from each other;

a detector connected to one of the pair of arms, the detector detecting a thickness of the test piece when the test piece is held between the pair of size measuring indenters; and

a control unit that performs zero-point correction with the output value of the detector when the pair of sizing indenters are brought into contact with each other as a zero point,

wherein the control unit has a determination unit that determines whether or not there is a deviation between an output value of the detector when the pair of size measuring indenters are brought into contact with each other before the size of the test piece is measured and a zero point at the time when zero point correction was performed last time,

when the determination unit determines that there is a deviation between the output value of the detector and the zero point at that time, the control unit terminates the size measurement operation without performing zero point correction on the output value of the detector.

2. The material testing machine according to claim 1,

the test apparatus further comprises a control device for controlling a test apparatus main body having a load mechanism for applying a test force to the test piece and a transport mechanism for transporting the test piece from the dimension measurement device to the test apparatus main body,

the control unit of the dimension measuring device transmits a stop signal to the control unit when the determination unit determines that there is a deviation between the output value of the detector and a zero point at the time when the pair of dimension measuring indenters are brought into contact with each other before the dimension of the test piece is measured,

the control device stops the conveyance of the test piece by the conveyance mechanism.

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