JPH07104236B2 - Stress relaxation test apparatus and stress relaxation test method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stress relaxation (relaxation) test apparatus and a stress relaxation test method, and more particularly to highly accurate stress relaxation of microstructures such as metal terminals. Apparatus and methods that can be tested at.

(Prior art and its problems) The stress relaxation test is a test object by subjecting a test object such as a metal material, rubber or plastic to a constant displacement and measuring the time change of the reaction force of the test object. This is a test for evaluating the characteristics of. To perform this test automatically,
Conventionally, various stress relaxation test devices (hereinafter, simply referred to as “test device”) have been proposed.

By the way, in the conventional test apparatus, a relatively large test piece is used as the test object, and it is difficult to accurately test the stress relaxation of the microstructure. The main cause is
This is the change in the ambient temperature of the test equipment. That is, in these test devices, the test object is sandwiched by two jigs to give a constant displacement. Therefore, when the ambient temperature changes, the jig thermally expands (or contracts) and the amount of displacement applied to the test object (hereinafter referred to as "test displacement")
Is changing. Usually, the amount of thermal expansion and contraction is small, and in a structure in which the test object is relatively large, the amount is negligible. Therefore, even if the amount of test displacement changes due to the thermal expansion / contraction of the jig, the performance evaluation and the function evaluation of the structure are not significantly affected.

However, as the size of the test object becomes smaller, the amount of thermal expansion and contraction cannot be ignored, and even a slight change in the test displacement in microstructures has a great impact on the performance evaluation and function evaluation of the structure. It is known that

In particular, when the microstructure is a structure made of a metal material with a large elastic coefficient such as copper or aluminum, for example, a terminal, even if the test displacement given to the structure changes slightly, the reaction force is large. However, the accuracy of the stress relaxation test will change significantly.

(Object of the Invention) The present invention has been made to solve the above problems, and an object of the present invention is to provide a stress relaxation test apparatus and a stress relaxation test method capable of accurately performing a stress relaxation test of a microstructure. And

(Means for Achieving the Object) The invention of claim 1 is a stress relaxation test for applying a constant displacement to a test object, measuring a reaction force of the test object, and testing stress relaxation of the test object. In order to achieve the above-mentioned object, the device sandwiches a test object by bringing the first and second jigs close to each other, gives a displacement to the test object, and also a reaction force of the test object. A measuring unit for measuring, a feedback unit having the same configuration as the measuring unit and provided in the vicinity of the measuring unit, a detecting unit for detecting a thermal expansion / contraction amount of the feedback unit, and the feedback unit thermally expanded. In some cases the first and second
While the jig is separated by the thermal expansion / contraction amount, when the jig is thermally contracted, the jig is brought closer to the thermal expansion / contraction amount to keep the displacement amount given to the test object constant.

Further, the invention of claim 2 is a stress relaxation test method for applying a constant displacement to a test object, measuring a reaction force of the test object, and testing stress relaxation of the test object. In order to achieve the above, a step of sandwiching the test object by bringing the first and second jigs close to each other and giving a predetermined displacement to the test object, and the same configuration as the first and second jigs In addition, when the thermal expansion and contraction amount of the third and fourth jigs provided near the first and second jigs is detected, and when the third and fourth jigs are thermally expanded, A step of separating the first and second jigs by the thermal expansion / contraction amount, and further bringing them closer by the thermal expansion / contraction amount when the thermal contraction occurs so as to keep the displacement amount given to the test object constant. Measuring the reaction force of the test object. .

(Operation) According to the invention of claim 1, the thermal expansion and contraction amount of the feedback portion is detected, and when the feedback portion thermally expands, the first and second jigs are separated by the thermal expansion and contraction amount. On the other hand, in the case of thermal contraction, the amount of thermal expansion and contraction is further reduced. Therefore, the amount of displacement given to the test object is kept constant without changing due to thermal expansion / contraction of the first and second jigs. As a result, the stress relaxation test is executed accurately.

Further, according to the invention of claim 2, the thermal expansion of the third and fourth jigs having the same structure as the first and second jigs and provided near the first and second jigs. When the contraction amount is detected and the third and fourth jigs are thermally expanded, the first and second jigs are separated by the thermal expansion and contraction amount, and when the third and fourth jigs are thermally contracted, the thermal expansion and contraction are performed. The reaction force of the test object is measured in the state in which the test object is further brought closer by an amount. Therefore, the stress relaxation test is executed with high precision, as in the invention of claim 1.

(Embodiment) FIG. 1 is an overall configuration diagram showing an embodiment of a stress relaxation test apparatus according to the present invention, and FIG. 2 is a partially enlarged view thereof. Further, FIG. 3 is a block diagram showing an electrical configuration of the test apparatus. As shown in FIG. 1, this test apparatus includes a measuring mechanism section 10 for displacing a minute structure under a predetermined condition to measure a reaction force thereof, and a measuring mechanism section 10 for controlling the measuring mechanism section 10 by the measuring mechanism section 10. The operation unit 50 outputs the obtained measurement result. In the following description, the test object is limited to the terminal T.

In the measurement mechanism section 10, columns 12 and 13 are vertically installed on the upper surface 11a of the pedestal 11 at regular intervals in a vertical direction, and a constant temperature bath 14 is provided on the pedestal 11 so as to be sandwiched between these columns 12 and 13. Has been. A beam 15 extending horizontally is installed on top of the columns 12 and 13.

The measuring mechanism section 10 is provided with a measuring section 20a for obtaining the stress relaxation characteristics of the terminal T which is the test object. As shown in FIG. 2, the measuring unit 20a includes a vertical movement mechanism 21a that vertically moves the terminal T to give a predetermined displacement to the terminal T, and a reaction force detection mechanism that detects the reaction force of the terminal T. Four
It consists of 0a.

In the vertical movement mechanism 21a, the stepping motor 2
2a is mounted in the pedestal 11. A ball screw 24a is connected to the drive shaft of the motor 22a via a speed reducer 23a. Further, a ball screw bracket 25a is screwed onto the tip of the ball screw 24a. Therefore, when the motor 22a is driven, the ball screw 24a rotates at a predetermined reduction ratio with respect to the rotation speed of the drive shaft, and the ball screw bracket 25a moves up and down. At the same time, the guide rods 26a, 2 fixed to the ball screw bracket 25a
7a also moves up and down while being guided by the guide plate 16.

A heat blocking jig 28a is fixed to the tops of the guide rods 26a and 27a. In addition, the heat shield jig 28a is connected to the rod 2
9a is erected vertically. As shown in FIG. 2, the rod 29a has a through hole provided on the lower surface of the constant temperature bath 14.
14a, and the sample mount 3
0a is fixed.

In the reaction force detection mechanism 40a, a jig 41a is provided inside the constant temperature bath 14 so as to face the sample mount 30a. The jig 41a is provided so as to project from the lower surface of the jig mounting portion 42a, and is directly above the through hole 14b by the rod 43a extending in the vertical direction and inserted into the through hole 14b provided on the upper surface of the constant temperature bath 14. It is connected to the lower surface of the heat-insulating jig 44a arranged in. Also,
The upper surface of this heat-insulating jig 44a is supported by the beam
Is connected to the load cell 46a fixed to the lower surface of the.
Therefore, when the reaction force from the terminal T is applied to the jig 41a, the reaction force is applied to the jig mounting portion 42a, the rod 43a, the heat blocking jig 44a,
The signal is applied to the load cell 46a via the shaft 45a, and a signal corresponding to the reaction force applied to the jig 41a is output from the load cell 46a.

Further, a feedback unit 20b is provided adjacent to the measuring unit 20a for detecting the amount of expansion (or contraction) of the measuring unit 20a due to temperature change. Since the configuration thereof is the same as that of the measuring unit 20a, the same or corresponding portions of the feedback unit 20b are designated by the corresponding reference numerals, and detailed description thereof will be omitted. Further, in this embodiment, three measuring units 20c, 20d, 20e are further provided adjacent to the feedback unit 20b so that a maximum of four terminals can be tested in one test.
These measuring units 20c, 20d, 20e also have the same configuration as the measuring unit 20a. Therefore, the description of the structure is also omitted here.

On the other hand, the operation unit 50 is provided with an operation table 51.
In addition, a control unit (not shown) including a microcomputer 52 that controls the entire test apparatus, a temperature controller 53 that controls the temperature of the constant temperature bath 14, a CRT 54 that displays a message to the operator, a keyboard 55, and an X -Y plotter 56
And are included.

The microcomputer 52, as shown in FIG. 3, has load cells 46a to 46e, a temperature controller 53, a CRT 54, a keyboard 55, an XY plotter 56, a stepping motor 22a to.
Drive units 57a to 57e for driving 22e are respectively connected, and the entire test apparatus is controlled according to the flow shown in FIGS. 4A and 4B.

4A and 4B are flowcharts showing the operation of the test apparatus configured as described above. In the following,
The test procedure of a certain terminal T will be described with reference to this flowchart.

Before starting the test, the operator uses the keyboard 55 to determine the amount of displacement (hereinafter referred to as “test displacement amount”) D _T to be applied to the terminal T and the load value W _F to be applied to the feedback unit 20b during the test. Enter sequentially. If necessary, enter other information about the test in the same manner.

After that, the operator sets the terminal T, which is the test object, on the sample mount 30a. At this time, the sample mount 3
0a is lowered downward, and the sample mount 30a and the jig 41a are separated by a predetermined distance so that the terminal T can be easily set. The sample mount 30b is also separated from the jig 41b. Therefore, at this point, the load cell
The load values detected by 46a and 46b are both zero.

Next, the operator operates the keyboard 55 to appropriately raise the sample mount 30a to a position where the upper surface of the terminal T contacts the jig 41a. Also, in the same way, the sample mount
The upper surface of 30b is brought into contact with the jig 41b. When these processes are completed, the operator inputs the fact that the sample preparation is completed to the control unit via the keyboard 55.

Accordingly, in step S1, the microcomputer 52
While continuously monitoring the load values W _T and W _F ′ detected by the load cells 46a and 46b, the sample mounts 30a and 30b are appropriately moved up and down so that the respective load values W _T and W _F ′ are Measuring unit 20a and feedback unit so that the specified small load value is obtained.
20b are controlled respectively. For convenience of description below, the height position of each sample mounting base 30a, 30b when each load value W _T , W _F ′ is a predetermined small load value is referred to as a load zero point.

Subsequently, the operator closes the door of the constant temperature bath 14, and further operates the operation panel (not shown) of the temperature controller 53 to set and input the test temperature, and the temperature of the constant temperature bath 14 is controlled by the temperature controller 53. The temperature of the constant temperature bath 14 is adjusted to the set temperature (step S2).

Also, in parallel with the temperature adjustment of the constant temperature bath 14 (step S2),
The same step as in step S1 is executed. This is because if this process is not performed in parallel with the temperature adjustment process (for example, the process of adjusting the temperature of the constant temperature bath 14 to a high temperature), a part of the measurement unit 20a expands as the temperature rises. This is because an extra displacement is given to the terminal T before the test.

After that, if the operator confirms that the equilibrium temperature of the constant temperature bath 14 has reached the set temperature and presses the start button (not shown), the processing of the following steps S3 to S8 is performed according to the instruction from the microcomputer 52. Executed, terminal T
Test will be conducted. Instead of waiting for the operator's confirmation as described above to perform the test, the test may be automatically started after a fixed time (for example, one hour) from the start of the temperature adjustment of the constant temperature bath 14.

First, in step S3, the sample mount 30a is moved upward from the zero load point by the test displacement amount D _T , and thus a predetermined displacement (test displacement amount D _T ) is applied to the terminal T. At the same time, while monitoring the load value W _F ′ detected by the load cell 46b, the sample mount 30b is gradually raised from the load zero point so that the load value W _F ′ becomes the load value W _F ′. Is controlled (step S4).

When the desired setting is completed in this way, the processes of steps S5 to S9 are then repeated periodically, and the reaction force W _T of the terminal _T is sequentially measured. That is, first, in step S5, the load value W _F ′ detected by the load cell 46b is set to the set load value W
It is determined whether or not it matches _F. If the feedback section 20 expands (or contracts) due to the temperature change around the test apparatus, the load value W _F ′ is different from the set load value W _F. Therefore, in this case, in step S6, the sample mounting base 30b is moved up (or down) by a minute distance Δ so that the load value W _F ′ and the set load value W _F match, and the small amount at that time is moved. The displacement amount Δ is obtained. This small displacement amount Δ corresponds to the expansion (or contraction) amount of the feedback portion 20b due to the temperature change around the test apparatus.

Next, in step S7, the sample mount 30a is moved by the minute displacement amount Δ. That is, since the measuring unit 20a and the feedback unit 20b have the same structure and are provided adjacent to each other, the expansion (or contraction) amount of both is the same, and the minute displacement Δ is the expansion of the measuring unit 20a. (Or contraction) amount is considered to match. Therefore, the sample mount 30a is lowered (or raised) by the minute displacement Δ.
By moving, the influence of expansion (or contraction) of the measuring unit 20a caused by the temperature change around the test apparatus is eliminated, and the displacement amount given to the terminal T is kept constant (test displacement amount D _T ).

When the process of step S7 ends, the process proceeds to step S8, and it is determined whether or not it is the load measurement time. Also, when it is determined in step S5 that the load value W _F ′ matches the set load value W _F , the process of step S8 is similarly executed. And
If it is determined that the load measurement time has not come, step S5
Then, the process of steps S5 to S7 is repeated again. In this way, the minute displacement amount Δ is obtained every moment, the position of the sample mounting base 30a is adjusted each time, and the influence of the expansion (or contraction) of the measurement unit 20a caused by the temperature change around the test apparatus is always eliminated. .

When the load measurement time is reached during the processing work of steps S5 to S8, the process proceeds from step S8 to step S9, and the load cell
The load value acting on 46a, that is, the reaction force of the terminal T is obtained and stored in the memory.

Thereafter, in step S10, it is determined whether or not the test is completed. If the test is not completed, the process returns to step S5 again, and steps S5 to
The process of S9 is repeated. In this way, the reaction force of the terminal T is sequentially obtained by the load cell 46a and stored in the memory at the test measurement time, while always eliminating the influence of the temperature change around the test apparatus.

The test end command is given, for example, by an operator pressing a stop button (not shown) or when a predetermined time has elapsed from the start of the test.
When the end of the test is determined in S10, the work ends.

After the sample is finished, the data stored in the memory is
The result can be confirmed by displaying it on the screen or plotting it on the XY plotter 56. Further, the above processing (CRT display, data plot) may be sequentially executed at the same time as the reaction force measurement.

In addition, in the above-described embodiment, the case of performing the test of one terminal T has been described, but this test apparatus can perform the test of four terminals at a maximum. In this case, each terminal is set on each of the sample mounts 30a, 30c, 30d, 30e, and the same processing as above is executed for each terminal.

Further, in the above-mentioned embodiment, the data regarding the reaction force W _T is measured at a predetermined time interval, but the reaction force is continuously measured in time.
It goes without saying that you may ask for W _T.

Next, the effects obtained when the test is performed as described above will be described with reference to specific examples. First, before investigating the effect, the feedback portion 20b of without operating the measuring unit 20A2,20c, 20d, were tested for each of the terminals _{T 1, T 2, T 3} , T 4 with 20e only, i.e. conventional A reaction force relaxation test was conducted under the same apparatus (method) conditions as in Example 1 to obtain the results shown in FIG. next,
Measuring unit 20a, 0c, 20 while operating feedback unit 20b
The same terminals T ₁ , T ₂ , T ₃ , T ₄ are tested with d, 20e and the 6th
The results shown in the figure were obtained.

In the former case, as can be seen from FIG. 5, no large fluctuation is observed in the measurement result from the start of the test until a certain time t ₁ , and the measurement is accurately performed. However, after that, fluctuations in the data occurred, and the accuracy of the test was significantly reduced.

On the other hand, in the latter case, as shown in FIG.
No significant fluctuations were found in the data, and accurate tests were performed.

In the above description, the test object is limited to the terminal T, but the test object is not limited to this and can be applied to microstructures in general. It can also be applied to relatively large structures.

Further, in the above-described embodiment, the load value W _F detected by the load cell 46b is the amount corresponding to the thermal expansion (or contraction) of the feedback unit 20b due to the temperature change around the test apparatus (small displacement Δ). Although it is detected by utilizing the fact that it changes according to the amount of thermal expansion (or contraction), the minute displacement amount Δ may be detected by a method other than this. For example, the feedback unit 20b
It may be possible to use that the distance between the sample mounting base 30b and the jig mounting portion 42b in 1 changes according to the temperature change around the test apparatus. That is, while continuously monitoring the above intervals by an appropriate means (for example, measurement by an optical interferometry method), the sample mount is set so that the intervals become a predetermined value.
The minute movement amount Δ may be obtained by moving 30b up and down.

Further, although four measuring units are provided in the above embodiment, the set number of measuring units is not particularly limited.

(Effects of the Invention) As described above, according to the invention of claim 1, the thermal expansion / contraction amount of the feedback portion is detected, and when the feedback portion is thermally expanded, the first and second jigs are subjected to the thermal treatment. While it is separated by the amount of expansion and contraction, when it is thermally contracted, it is made closer by the amount of thermal expansion and contraction, so the amount of displacement given to the test object can be kept constant, and the stress relaxation test can be performed accurately. It can be performed.

Further, according to the invention of claim 2, the thermal expansion of the third and fourth jigs having the same structure as the first and second jigs and provided near the first and second jigs. The contraction amount is detected, and when the third and fourth jigs are thermally expanded, the first and second jigs are separated by the thermal expansion and contraction amount, and when the third and fourth jigs are thermally contracted, the thermal expansion and contraction are performed. Because the reaction force of the test object is measured in that state by further approaching by the amount, the same effect as the invention of claim 1 can be obtained.

[Brief description of drawings]

1 is an overall configuration diagram showing an embodiment of a stress relaxation test apparatus according to the present invention, FIG. 2 is a partially enlarged view thereof, FIG. 3 is a block diagram showing an electrical configuration of the test apparatus, and FIG. 4A. And FIG. 4B is a flowchart showing the operation of the test apparatus, FIG. 5 is a view showing the result of the stress relaxation test by the conventional test apparatus, and FIG. 6 is the result of the stress relaxation test by the stress relaxation test apparatus according to the present invention. FIG. 20a, 20c, 20d, 20e …… Measuring section, 20b …… Feedback section, 52 …… Microcomputer, T …… Terminal

Claims (2)

[Claims] 1. A stress relaxation test apparatus for applying a constant displacement to a test object, measuring a reaction force of the test object, and testing stress relaxation of the test object. The test object is sandwiched by bringing the tool close to each other, and a displacement is applied to the test object, and a measuring unit that measures the reaction force of the test object, and the same configuration as the measuring unit, and the measuring unit A feedback unit provided in the vicinity of the feedback unit, a detection unit for detecting the thermal expansion / contraction amount of the feedback unit, and when the feedback unit thermally expands, the first and second jigs are separated by the thermal expansion / contraction amount. While letting
A stress relaxation test apparatus comprising: a control unit which, when heat-shrinks, further moves closer by the heat-expansion / shrinkage amount to keep a displacement amount applied to the test object constant. 2. A stress relaxation test method, wherein a constant displacement is applied to a test object, the reaction force of the test object is measured, and stress relaxation of the test object is tested. A step of sandwiching a test object by bringing a tool close to the test object, and displacing the test object; and a configuration similar to that of the first and second jigs, and a position near the first and second jigs. Detecting the amount of thermal expansion and contraction of the third and fourth jigs provided in the first and second jigs, and the first and second jigs when the third and fourth jigs are thermally expanded.
And a step of separating the second jig by the thermal expansion and contraction amount, and further bringing the second jig closer to the thermal expansion and contraction amount when the thermal contraction occurs to keep the displacement amount given to the test object constant. And a step of measuring a reaction force of the object.