A method and device for testing copper foil tensile strength

Abstract

The present invention relates to the technical field of copper foil tensile testing, and specifically to a method and device for copper foil tensile testing. The method analyzes the real-time changes in the stretching of a copper foil sample and the amplitude of the tensile change to obtain a stretching stage index, adjusts the stretching rate at the current moment in real time according to the state of the stretching stage, and analyzes the stage change according to the change of the stretching stage index to determine the stage change moment; further adjusts the stretching rate according to the degree of deformation of the copper foil sample after the stage change moment; and obtains a more reliable copper foil stretching sample according to the degree of stretching of the sample. The present invention analyzes the degree of stretching of the copper foil sample in real time, adjusts the stretching rate in combination with the different stretching stages, and improves the retention degree of the copper foil sample data during stretching, so that the obtained stretching sample is more reliable and the subsequent analysis data is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of copper foil tensile testing, and in particular to a method and a device for copper foil tensile testing. Background Art

[0002] Copper foil is a very important material in the electronics industry. It is mainly used to manufacture printed circuit boards (PCBs) and other electronic components. After the production of copper foil is completed, multiple tests are usually required, among which the copper foil tensile test is an important test content. The copper foil tensile test is an important test method used to evaluate the mechanical properties of copper foil materials. This test is mainly used to determine the tensile strength, elongation and other parameters of copper foil when subjected to tensile force, so as to judge the applicability and reliability of copper foil.

[0003] When conducting a copper foil tensile test, the traditional tensile test method usually selects a relatively fixed slow pulling speed or manually controls the speed during pulling. Although a uniform slow pulling can obtain a rough tensile limit data, it may not be the tensile limit of the copper foil, and when the speed is not selected appropriately, the stretched sample will be easily damaged. Since the mechanical properties of the material will change with the strain rate, when the stretching speed is too fast, the strain rate may be too fast, resulting in data loss in the sensor, which ultimately makes the stretched sample unreliable, and the accuracy of the tensile test data obtained by subsequent analysis is also low. Summary of the invention

[0004] In order to solve the technical problems in the prior art that the stretched samples are unreliable and the accuracy of the tensile test data obtained by subsequent analysis is also low, the purpose of the present invention is to provide a method and device for copper foil tensile testing, and the technical solutions adopted are as follows:

[0005] The present invention provides a method for copper foil tensile testing, the method comprising:

[0006] Obtaining the initial stretching rate of the copper foil sample and the sample length at each sampling moment;

[0007] When the copper foil sample begins to stretch, the stretching stage index at the current moment is obtained according to the stretching amplitude of the sample length and the growth of the tension at the current moment; the stretching rate at the current sampling moment is determined based on the stretching stage index at the current moment and the stretching rate at the previous sampling moment;

[0008] Determine the stage change moment based on the difference between the current moment and the previous sampling moment in the stretching stage index;

[0009] After the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is adjusted according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment;

[0010] The completion of the stretching is determined based on the sample length of the copper foil sample at the current moment, and the copper foil stretching sample is obtained.

[0011] Furthermore, the sample length is the side length of grid markings evenly marked on the surface of the copper foil sample.

[0012] Furthermore, the method for obtaining the stretching stage index includes:

[0013] The difference between the maximum value of the sample length at the current moment and the sample length when the copper foil sample starts to stretch is taken as the stretching length at the current moment;

[0014] The time interval between the current moment and the start of the copper foil sample stretching is taken as the stretching duration at the current moment;

[0015] The ratio of the stretching length at the current moment to the stretching duration is used as the deformation index at the current moment;

[0016] Obtain the tension data at each sampling moment, and use the difference in tension data between the current moment and the previous sampling moment as the tension increase at the current moment;

[0017] The deformation index at the current moment and the tension increase are combined to obtain the stretching stage index at the current moment.

[0018] Further, the stretching rate at the current sampling moment is determined based on the stretching stage index at the current moment and the stretching rate at the previous sampling moment, including:

[0019] The product of the value of the negatively correlated and normalized stretching stage index at the current moment and the initial stretching rate is used as the speed adjustment value at the current moment;

[0020] The difference between the stretching rate at the previous sampling moment and the speed adjustment amount is used as the stretching rate at the current moment.

[0021] Furthermore, the step of determining the stage change moment based on the difference between the stretching stage index at the current moment and the previous sampling moment includes:

[0022] The difference between the normalized stretching stage index at the current moment and the previous sampling moment is taken as the change amplitude at the current moment;

[0023] When the change amplitude is greater than the preset change threshold, the current moment is regarded as the stage change moment.

[0024] Further, after the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is adjusted according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment, including:

[0025] Calculate the difference between the length of each sample at the current moment and the length of the sample when the copper foil sample starts to stretch, and calculate the sum of all the differences to obtain the deformation amplitude at the current moment;

[0026] The attenuation at the current moment is obtained by multiplying the normalized value of the deformation amplitude at the current moment by the stretching rate at the previous sampling moment;

[0027] The difference between the stretching rate and the attenuation at the previous sampling moment is used as the stretching rate at the current moment.

[0028] Further, the step of determining the completion of stretching based on the sample length of the copper foil sample at the current moment to obtain the copper foil stretching sample includes:

[0029] The difference between the maximum value of the sample length at the current moment and the sample length when the copper foil sample starts to stretch is taken as the stretching amplitude at the current moment;

[0030] When the stretching amplitude is greater than the preset stretching length of the copper foil sample, the stretching is stopped to obtain the copper foil stretching sample.

[0031] Furthermore, the combining of the deformation index and the tension increase at the current moment to obtain the stretching stage index at the current moment includes:

[0032] The product of the value after negative correlation mapping and normalization of the deformation index and the tensile force increase is normalized to obtain the tensile stage index at the current moment.

[0033] Furthermore, the method for obtaining the initial stretching rate includes:

[0034] Obtaining the area and thickness of the copper foil sample; taking the product of the area and thickness of the copper foil sample as the size index of the copper foil sample; taking the product of the preset maximum area and the preset maximum thickness as the maximum size index;

[0035] The ratio of the size index of the copper foil sample to the maximum size index is used as the tensile load capacity of the copper foil sample;

[0036] The product of the tensile load capacity and the preset rate range is used as the initial rate adjustment amount of the copper foil sample; the sum of the initial rate adjustment amount and the preset minimum tensile rate is used as the initial tensile rate of the copper foil sample.

[0037] The present invention also provides a copper foil tensile testing device, comprising:

[0038] A data acquisition module is used to obtain the initial stretching rate of the copper foil sample and the sample length at each sampling moment;

[0039] The rate adjustment module is used to obtain the stretching stage index at the current moment according to the stretching amplitude and tension growth of the sample length at the current moment when the copper foil sample begins to stretch; based on the stretching stage index at the current moment and the stretching rate at the previous sampling moment, determine the stretching rate at the current sampling moment;

[0040] Determine the stage change moment based on the difference between the current moment and the previous sampling moment in the stretching stage index;

[0041] After the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is adjusted according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment;

[0042] The stretching sample acquisition module is used to determine the stretching completion status based on the sample length of the copper foil sample at the current moment and obtain the copper foil stretching sample.

[0043] The present invention has the following beneficial effects:

[0044] The present invention performs real-time change analysis on the stretching process of the copper foil sample, analyzes the state of the copper foil sample being stretched according to the stress increase and deformation during the stretching process of the sample, obtains the stretching stage index, considers the different degrees of change of tension and deformation in different samples, quantifies the state of the copper foil sample being stretched by real-time changes, and prevents the untimely or misjudgment of the subsequent stage. When the stretching rate is adjusted according to the stretching stage index, the stretching rate is reduced to ensure the retention of the sample structure, that is, the stretching rate at the current moment and the stretching rate at the previous moment are in a decaying trend. The stage division is carried out by the change of the stretching stage index of different samples, and the stage change point is determined by the sudden change of the quantitative state, so that the rate adjustment of different sample structures can be guaranteed, and the risk of inadaptability of the fixed stage division is reduced. After the stage change, due to the reduction of the influence of the tension change, when it is more necessary to ensure that the stretching structure is not destroyed, the stretching rate is further attenuated by the deformation situation to ensure the stability of the overall stretching of the copper foil sample. At this time, when the stretching is completed according to the degree of stretching of the sample, a more reliable copper foil stretching sample can be obtained. The present invention analyzes the degree of stretching of the copper foil sample in real time through tension and deformation, adaptively divides the stretching stages to perform attenuation adjustments of different stretching rates, and improves the retention degree of the copper foil sample data during stretching, making the obtained stretched sample more reliable and the subsequent analysis data more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A method and device for copper foil tensile testing provided by one embodiment of the present invention;

[0047] Figure 2 A schematic diagram of stress-strain curves of different copper foil samples provided by one embodiment of the present invention;

[0048] Figure 3 An embodiment of the present invention provides Figure 2 Partial schematic diagram of the curve in part A. DETAILED DESCRIPTION

[0049] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a method and device for copper foil tensile testing proposed by the present invention, its specific implementation, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0050] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0051] The specific scheme of the method and device for copper foil tensile testing provided by the present invention is described in detail below with reference to the accompanying drawings.

[0052] See also Figure 1 , which shows a flow chart of a method for copper foil tensile testing provided by an embodiment of the present invention, the method comprising the following steps:

[0053] S1: Obtain the initial stretching rate of the copper foil sample and the sample length at each sampling moment.

[0054] The copper foil tensile test is mainly carried out based on a universal material testing machine. The two ends of the copper foil sample are fixed in the fixture of the machine by a fixture. During the test, one end remains fixed and the other end is driven by a motor to slowly stretch the copper foil. Finally, the performance of the copper foil is evaluated by multiple sensors. In a specific implementation of an embodiment of the present invention, the preliminary preparations required for the copper foil tensile test include:

[0055] 1) Prepare copper foil samples of appropriate size to be tested. The size parameters of the copper foil samples are limited to length [50mm, 200mm], width [10mm, 25mm] and thickness [10μm, 200μm]. It should be noted that the specific size depends on the test equipment and the standard of actual use, and is not limited here;

[0056] 2) Mark grid lines evenly on the surface of the copper foil sample to be tested, and use the side length as the sample length, which is 5 mm;

[0057] 3) Control the temperature and humidity of the test environment. Normally, the temperature is maintained at 23℃±2℃ and the humidity is maintained at 50%±5%;

[0058] 4) Check the alignment and balance of the test equipment to ensure that the equipment can operate accurately;

[0059] 5) Debug the sensor module of the tensile test equipment to ensure that the sensor and data acquisition system can operate normally;

[0060] 6) Set the data collection frequency of the sensor to 50 Hz, that is, the sensor collects data 50 times per second, and uploads and stores the data collected by the sensor.

[0061] At this point, all the preliminary preparations are completed.

[0062] When conducting a copper foil tensile test, different initial tensile speeds are usually selected for copper foils of different sizes to improve the reliability of the tensile test results. For thicker and wider copper foils, the force distribution is more uniform and the tensile bearing capacity is stronger, so a higher initial tensile speed rate can be used. Conversely, for thinner and narrower copper foils, since they are more sensitive to tensile force, a lower initial tensile speed rate is required.

[0063] In some achievable manners of the embodiments of the present invention, the method for obtaining the initial stretching rate includes:

[0064] First, the area and thickness of the copper foil sample are obtained, and the product of the area and thickness of the copper foil sample is used as the size index of the copper foil sample. The product of the preset maximum area and the preset maximum thickness is used as the maximum size index. In the embodiment of the present invention, the area and thickness of the copper foil sample are selected within the size parameter restrictions, and the preset maximum area and the preset maximum thickness are also known in the preparation stage of the embodiment. The specific numerical values ​​are adjusted by the implementer according to the implementation scenario and are not limited here.

[0065] The ratio of the size index of the copper foil sample to the maximum size index is further used as the tensile load capacity of the copper foil sample. The size of the copper foil sample can be obtained by comparing the size of the copper foil sample in the preparation stage with the maximum size.

[0066] Finally, the product of the tensile load capacity and the preset speed range is used as the initial speed adjustment amount of the copper foil sample. For copper foil samples with higher sizes, the initial speed can be higher. The sum of the initial speed adjustment amount and the preset minimum tensile speed is used as the initial tensile speed of the copper foil sample. In the embodiment of the present invention, the preset minimum tensile speed can be set to 6 mm / s, and the preset speed range is [6,12]. The speed range is 6. The specific numerical value can be adjusted by the implementer according to the specific implementation scenario, and is not limited here.

[0067] At this point, the preparation for the copper foil sample stretching is completed. It should be noted that, usually, the initial stretching rate is the maximum stretching rate during the test, and as the test progresses, the stretching rate will gradually decrease to ensure the integrity of the copper foil sample.

[0068] S2: When the copper foil sample begins to stretch, the stretching stage index at the current moment is obtained according to the stretching amplitude of the sample length and the growth of the tension at the current moment; based on the stretching stage index at the current moment and the stretching rate at the previous sampling moment, the stretching rate at the current sampling moment is determined.

[0069] When the copper foil sample begins to stretch, in order to make the copper foil reach the yield stage as soon as possible without reaching the stretching limit too quickly, a higher stretching rate is usually set and gradually reduced during the stretching process to ensure that the copper foil limit is not instantly crossed and the copper foil is broken. In the early stage of stretching, the copper foil sample is greatly affected by the tension. The stage change is judged by the change in tension, and the rate is continuously adjusted to reduce.

[0070] In material mechanics, the yield stage refers to a specific stage in which a material transitions from elastic deformation to plastic deformation when subjected to external forces. Specifically, when the stress on a material exceeds its elastic limit, the deformation of the material will continue to increase even if the stress no longer increases, and the material enters the yield stage.

[0071] First, the stretching process before entering the yield stage is analyzed in real time. When sampling is performed at the current moment, the stretching amplitude and tension are analyzed to obtain the stretching stage index at the current moment to reflect the stretching state. Continuous adjustments are made at the current moment based on the stretching stage index to ensure safe and reliable stretching.

[0072] Preferably, in some possible implementations of the embodiments of the present invention, the method for obtaining the stretching stage index includes:

[0073] First, the difference between the maximum sample length at the current moment and the sample length when the copper foil sample starts to stretch is taken as the stretching length at the current moment. Due to the influence of the stretching process, the sample length marked on the surface of the copper foil sample will be deformed, and the case with the largest change can reflect the degree of stretching.

[0074] Furthermore, the time interval between the current moment and the start of stretching of the copper foil sample is taken as the stretching duration at the current moment. Further combined with the stretching time, the ratio of the stretching length at the current moment to the stretching duration is taken as the deformation index at the current moment, reflecting the overall deformation degree of the stretching deformation.

[0075] The tension data at each sampling moment is further obtained, and the difference in tension data between the current moment and the previous sampling moment is monitored by the sensor during the stretching process, and is used as the tension increase at the current moment, reflecting that the degree of change in the tension effect is relatively high.

[0076] Finally, the deformation and the degree of tension are combined to reflect the stage of stretching. When the degree of change in tension is higher and the overall deformation is lower, it means that it is more likely to be close to the initial stage of stretching. Combined with the deformation index and the tension increase at the current moment, the stretching stage index at the current moment is obtained.

[0077] In an embodiment of the present invention, the product of the value after negative correlation mapping and normalization of the deformation index and the tensile force increase is normalized to obtain the tensile stage index at the current moment. The larger the deformation index, the higher the overall deformation degree, and the smaller the tensile force increase, the smaller the degree of change in the tensile force. Therefore, the smaller the tensile stage index, the closer the copper foil sample is to the yield stage.

[0078] It should be noted that negative correlation mapping and normalization processing are technical means well known to technical personnel in this field. For example, negative correlation mapping can be in the form of inverse proportion or negative exponential power, and normalization processing can be linear normalization or nonlinear normalization, etc., which will not be elaborated or limited here.

[0079] The current stretching rate is further adjusted by the stretching stage index at the current moment. When the stretching stage index is smaller, it means that it is closer to the yield stage. At this time, the stretching rate should be smaller to ensure the transition stability.

[0080] Preferably, in the embodiment of the present invention, the product of the value of the negative correlation mapping and normalization of the tensile stage index at the current moment and the initial tensile rate is used as the speed adjustment amount at the current moment. When the tensile stage is smaller, the speed attenuation amount needs to be larger to improve the smoothness of entering the yield stage. Then, the difference between the tensile rate at the previous sampling moment and the speed adjustment amount is used as the tensile rate at the current moment to complete the adjustment of the tensile rate at the current moment.

[0081] The copper foil sample is further stretched based on the stretching rate at the current moment until the next sampling moment.

[0082] S3: Determine the stage change time based on the difference between the current time and the previous sampling time in the stretching stage index.

[0083] In the initial stage of copper foil stretching, the increase in tension is large while the deformation of the copper foil is small, which is the elastic deformation stage. As the tension gradually increases, the internal structure of the copper foil is gradually destroyed, the deformation of the copper foil gradually increases, and the increase in tension begins to decrease, which is the yield stage.

[0084] See also Figure 2 , which is a schematic diagram showing stress-strain curves of different copper foil samples provided by an embodiment of the present invention, Figure 3 , which shows an embodiment of the present invention provides Figure 2 The partial schematic diagram of the curve in part A, stress refers to the magnitude of the force acting on the surface of an object per unit area, which is the tensile force in the embodiment of the present invention, and strain refers to the measure of the relative change in the size or shape of an object when it is subjected to an external force. During the stretching process of the copper foil sample, the relationship between the tensile force and the degree of deformation is different at different stages.

[0085] When the copper foil is closer to the yield point, the deformation degree usually increases suddenly. Since the sudden change is not caused by tension, the change in tension will not change significantly, which will further reduce the tensile stage index. Therefore, the stage change can be determined by the change in the tensile stage index.

[0086] In an embodiment of the present invention, a method for obtaining a phase change moment includes:

[0087] The difference between the normalized stretching stage index at the current moment and the previous sampling moment is taken as the change amplitude at the current moment. When the change amplitude is greater than the preset transformation threshold, the current moment is taken as the stage change moment. When the change amplitude exceeds the expected threshold, it means that the stage has changed, and the current moment can be taken as the stage change moment. In the embodiment of the present invention, the preset transformation threshold is set to 0.3. The specific data implementer can adjust it by himself, and there is no limitation here.

[0088] S4: After the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is adjusted according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment.

[0089] Since the stage change indicates that the internal structure of the copper foil sample has undergone a large mutation, the subsequent stretching rate is no longer suitable for the current copper foil sample and needs to be readjusted. Since the tensile stress of the copper foil sample and the tensile growth rate begin to change nonlinearly at this time, it is not appropriate to adjust it through the tensile stage index.

[0090] By analyzing the data changes of the marking lines on the surface of the copper foil sample, the current deformation state of the copper foil sample is further analyzed. When in the yield stage, the surface of the copper foil sample must have a certain degree of deformation. By comparing the deformation degree of the grid marking lines on the surface of the copper foil, the stretching rate can be further adjusted more accurately.

[0091] Preferably, in an embodiment of the present invention, a method for acquiring the stretching rate at the current moment after the stage change moment of the copper foil sample being stretched comprises:

[0092] First, calculate the difference between the length of each sample at the current moment and the sample length when the copper foil sample starts to stretch, and find the sum of all differences to obtain the deformation amplitude at the current moment. During the stretching process, the side length of the network marking line will change, and different side lengths will deform to different degrees. The difference between the multiple sample lengths and the initial sample length is combined to reflect the deformation degree.

[0093] The attenuation at the current moment is obtained by further multiplying the normalized value of the deformation amplitude at the current moment by the stretching rate at the previous sampling moment. The larger the deformation amplitude, the closer the copper foil sample is to the limit, and the smaller the required stretching rate is to ensure that the stretching limit is reached smoothly.

[0094] Finally, the difference between the stretching rate and the attenuation at the previous sampling moment is used as the stretching rate at the current moment, and stretching is performed to the next sampling moment using the stretching rate at the current moment.

[0095] At this point, the analysis of rate decay in the yield stage is completed.

[0096] S5: Determine the completion of stretching based on the sample length of the copper foil sample at the current moment, and obtain the copper foil stretching sample.

[0097] It should be noted that copper is a material with good ductility, and its elongation limit under normal conditions is 20%-40%. Therefore, in the embodiment of the present invention, when the extension amplitude of the copper foil is greater than half of its initial state, it is considered that the tensile limit has been reached.

[0098] Therefore, in the embodiment of the present invention, the difference between the maximum value of the sample length at the current moment and the sample length when the copper foil sample starts to be stretched is used as the stretching amplitude at the current moment. When the stretching amplitude is greater than the preset stretching length of the copper foil sample, the stretching is stopped to obtain the copper foil stretched sample. In the embodiment of the present invention, the preset stretching length is half of the length of the copper foil sample, which is not limited here.

[0099] At this point, a copper foil tensile sample that is stable to the limit of tensile strength is obtained through real-time adjustment. After the first copper foil tensile test is completed, the above steps are repeated to test different copper foil samples of the same batch to obtain multiple sets of copper foil tensile test data;

[0100] In an embodiment of the present invention, the mean of multiple groups of tensile test data can be calculated, and the tensile test data includes calculated elastic modulus, yield strength, maximum strength and elongation, etc. After obtaining all the required copper foil tensile test data, the data is compared according to industry standards, specifications or specific requirements of customers. It should be noted that when any item in the data does not meet the required specifications, it can be marked and the deviation value of the data can be calculated. Finally, the performance of the copper foil is evaluated based on the data comparison results, such as the conductivity and durability requirements of the copper foil in electronic products, and the evaluation results, test conditions, test data and other information are recorded to obtain a tensile test report for the current copper foil product.

[0101] It should be noted that, in order to facilitate calculation, all indicator data involved in the calculation in the embodiment of the present invention are preprocessed to eliminate the dimension effect. The specific means of eliminating the dimension effect are technical means well known to those skilled in the art and are not limited here.

[0102] In summary, the present invention performs a real-time change analysis on the stretching process of the copper foil sample, performs a state analysis of the copper foil sample being stretched according to the stretching change, obtains a stretching stage index, adjusts the stretching rate at the current moment in real time according to the state degree of the stretching stage, and performs a stage change analysis according to the change of the stretching stage index, to avoid the situation where the copper foil sample structure is damaged due to the stage change and the stretching rate is not adjusted. Therefore, after the stage change, that is, the copper foil sample is stretched into the yield stage, the rate is further adjusted by the degree of deformation of the copper foil sample being stretched in this stage to ensure the stability of the overall stretching of the copper foil sample. At this time, when the stretching is completed according to the degree of the sample being stretched, a more reliable copper foil stretching sample can be obtained. The present invention improves the retention degree of the copper foil sample data during stretching by analyzing the degree of stretching of the copper foil sample in real time, combining the different adjustment of the stretching rate in the stretching stage, so that the obtained stretching sample is more reliable and the subsequent analysis data is more accurate.

[0103] The present invention also provides a copper foil tensile testing device, comprising:

[0104] A data acquisition module is used to obtain the initial stretching rate of the copper foil sample and the sample length at each sampling moment;

[0105] The rate adjustment module is used to obtain the stretching stage index at the current moment according to the stretching amplitude and tension growth of the sample length at the current moment when the copper foil sample begins to stretch; based on the stretching stage index at the current moment and the stretching rate at the previous sampling moment, determine the stretching rate at the current sampling moment;

[0106] Determine the stage change moment based on the difference between the current moment and the previous sampling moment in the stretching stage index;

[0107] After the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is adjusted according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment;

[0108] The stretching sample acquisition module is used to determine the stretching completion status based on the sample length of the copper foil sample at the current moment and obtain the copper foil stretching sample.

[0109] Since the specific implementation process of a copper foil tensile testing device in this embodiment is the same as the specific implementation process of a copper foil tensile testing method described above, it will not be described in detail here.

[0110] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0111] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for copper foil tensile testing, characterized in that: The method comprises: Obtaining the initial stretching rate of the copper foil sample and the sample length at each sampling moment; When the copper foil sample begins to stretch, the deformation index at the current moment is determined according to the stretching length and stretching time at the current moment, and the deformation index represents the stretching amplitude of the sample length; the tension increase at the current moment is obtained according to the difference in tension data between the current moment and the previous sampling moment, and the tension increase represents the tension enhancement; the stretching stage index at the current moment is obtained by combining the deformation index at the current moment and the tension increase, and the deformation index is negatively correlated with the stretching stage index, and the tension increase is positively correlated with the stretching stage index; the stretching rate at the previous sampling moment is reduced by the stretching stage index at the current moment, and the stretching rate at the current sampling moment is determined; Determine the stage change moment based on the difference between the current moment and the previous sampling moment in the stretching stage index; After the copper foil sample is stretched for a stage change, the stretching rate at the previous sampling moment is reduced according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment; Determine the completion of stretching based on the sample length of the copper foil sample at the current moment, and obtain the copper foil stretching sample; The step of determining the stage change time based on the difference between the current moment and the previous sampling moment in the stretching stage index includes: The difference between the normalized stretching stage index at the current moment and the previous sampling moment is taken as the change amplitude at the current moment; When the change amplitude is greater than the preset change threshold, the current moment is regarded as the stage change moment; After the copper foil sample is stretched at a stage change moment, the stretching rate at the previous sampling moment is reduced according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment, including: Calculate the difference between the length of each sample at the current moment and the length of the sample when the copper foil sample starts to stretch, and calculate the sum of all the differences to obtain the deformation amplitude at the current moment; The attenuation at the current moment is obtained by multiplying the normalized value of the deformation amplitude at the current moment by the stretching rate at the previous sampling moment; The difference between the stretching rate and the attenuation at the previous sampling moment is used as the stretching rate at the current moment; The method of combining the deformation index at the current moment with the tension increase to obtain the stretching stage index at the current moment includes: The product of the value after negative correlation mapping and normalization of the deformation index and the tensile force increase is normalized to obtain the tensile stage index at the current moment.

2. A method for copper foil tensile testing according to claim 1, characterized in that: The sample length is the side length of the grid lines evenly marked on the surface of the copper foil sample.

3. A method for copper foil tensile testing according to claim 2, characterized in that: The method for obtaining the deformation index includes: The difference between the maximum value of the sample length at the current moment and the sample length when the copper foil sample starts to stretch is taken as the stretching length at the current moment; The time interval between the current moment and the start of the copper foil sample stretching is taken as the stretching duration at the current moment; The ratio of the stretching length at the current moment to the stretching duration is used as the deformation index at the current moment.

4. The method for copper foil tensile testing according to claim 1, characterized in that: The step of reducing the stretching rate at the previous sampling moment by the stretching stage index at the current moment to determine the stretching rate at the current sampling moment includes: The product of the value of the negatively correlated and normalized stretching stage index at the current moment and the initial stretching rate is used as the speed adjustment value at the current moment; The difference between the stretching rate at the previous sampling moment and the speed adjustment amount is used as the stretching rate at the current moment.

5. The method for copper foil tensile testing according to claim 1, characterized in that: The method of determining the completion of stretching based on the sample length of the copper foil sample at the current moment to obtain the copper foil stretching sample includes: The difference between the maximum value of the sample length at the current moment and the sample length when the copper foil sample starts to stretch is taken as the stretching amplitude at the current moment; When the stretching amplitude is greater than the preset stretching length of the copper foil sample, the stretching is stopped to obtain the copper foil stretching sample.

6. A method for copper foil tensile testing according to claim 1, characterized in that: The method for obtaining the initial stretching rate includes: Obtaining the area and thickness of the copper foil sample; taking the product of the area and thickness of the copper foil sample as the size index of the copper foil sample; taking the product of the preset maximum area and the preset maximum thickness as the maximum size index; The ratio of the size index of the copper foil sample to the maximum size index is used as the tensile load capacity of the copper foil sample; The product of the tensile load capacity and the preset rate range is used as the initial rate adjustment amount of the copper foil sample; the sum of the initial rate adjustment amount and the preset minimum tensile rate is used as the initial tensile rate of the copper foil sample.

7. A copper foil tensile testing device, used to implement a copper foil tensile testing method as claimed in any one of claims 1 to 6, characterized in that: include: A data acquisition module is used to obtain the initial stretching rate of the copper foil sample and the sample length at each sampling moment; The rate adjustment module is used to determine the deformation index at the current moment according to the stretching length and stretching duration at the current moment during the stretching process of the copper foil sample, wherein the deformation index represents the stretching amplitude of the sample length; obtain the tension increase at the current moment according to the difference in tension data between the current moment and the previous sampling moment, wherein the tension increase represents the tension enhancement; obtain the stretching stage index at the current moment by combining the deformation index and the tension increase at the current moment, wherein the deformation index is negatively correlated with the stretching stage index, and the tension increase is positively correlated with the stretching stage index; reduce the stretching rate at the previous sampling moment by the stretching stage index at the current moment, and determine the stretching rate at the current sampling moment; Determine the stage change moment based on the difference between the current moment and the previous sampling moment in the stretching stage index; After the copper foil sample is stretched for a stage change, the stretching rate at the previous sampling moment is reduced according to the sample length deformation degree of the copper foil sample at the current moment to obtain the stretching rate at the current moment; The stretching sample acquisition module is used to determine the stretching completion status based on the sample length of the copper foil sample at the current moment and obtain the copper foil stretching sample.

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