Cracking time prediction model acquisition method, cracking time prediction device and medium

Abstract

The cracking time prediction model acquisition method, cracking time prediction device and medium provided by the embodiments of the present invention can obtain the second fracture tensile parameter of the tensile spline after placing the tensile spline of the same material as the injection molded product in the same first simulated application environment for a time reaching the first cracking time value based on the first cracking time value of the injection molded product, and determine the cracking judgment standard parameter v according to the first fracture tensile parameter of the tensile spline in the standard test environment; and then obtain the second cracking time values ​​reaching the cracking judgment standard parameter v in at least two second simulated application environments according to v, so as to establish a curve equation of the application environment parameter value and the second cracking time value as a prediction model according to the obtained at least two pairs of application environment parameter values ​​and second cracking time values, so as to predict the cracking time of the same injection molded product in different application environments, so that the detection is more intelligent and convenient, the cost is lower, and the efficiency is higher.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of crack detection of injection molded product components, and in particular to a method for obtaining a crack time prediction model, a crack time prediction device and a medium. Background Art

[0002] PC / ABS, a mixture of polycarbonate and acrylonitrile-butadiene-styrene copolymer, is a thermoplastic plastic formed by the combination of polycarbonate (Polycarbonate) and acrylonitrile-butadiene-styrene copolymer (ABS). It combines the excellent properties of the two materials, the formability of ABS material and the mechanical properties, impact strength, heat resistance, and UV resistance of PC. It is transparent and particle-free and can be widely used in automotive interior parts, business machines, communication equipment, household appliances, and lighting equipment. PC / ABS injection molding products will experience environmental stress cracking during use. Environmental stress cracking refers to the cracking and damage of PC / ABS injection molding products due to the presence of external mechanical stress or internal stress under the erosion of environmental solvents. Environmental stress cracking may cause damage to PC / ABS injection molding products and premature failure, resulting in huge economic losses. However, since PC / ABS injection molded products cannot be used as test tensile specimens, in the related art, the cracking time of PC / ABS injection molded products can only be tested on-site according to their actual application environment. When the application environment changes, they can only be completely retested, which leads to inconvenience in testing, high testing costs and low efficiency. Summary of the invention

[0003] The embodiments of the present invention mainly provide a method for obtaining a cracking time prediction model, a cracking time prediction device and a medium, aiming to solve the problems of inconvenience in detecting the cracking time of PC / ABS injection molded products in the related art, high detection cost and low efficiency.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides a method for obtaining a cracking time prediction model, comprising:

[0005] Obtaining a first cracking time value of the injection molded product when cracks occur in a first simulated application environment, wherein the first simulated application environment is obtained by simulating and setting the actual application environment of the injection molded product;

[0006] When the time for placing the tensile spline in the first simulated application environment reaches the cracking time value, obtaining a second fracture tensile parameter of the tensile spline, wherein the material of the tensile spline is consistent with the injection molded product;

[0007] Determining a cracking judgment standard parameter v according to the first fracture tensile parameter of the tensile spline under the standard test environment and the obtained second fracture tensile parameter;

[0008] Obtaining the second cracking time values ​​of the stretched spline reaching the cracking judgment standard parameter v in at least two second simulated application environments, wherein different second simulated application environments have different environmental parameter values, thereby obtaining at least two pairs of application environment parameter values ​​and second cracking time values;

[0009] According to the at least two pairs of application environment parameter values ​​and the second cracking time values, a curve equation of the application environment parameter values ​​and the second cracking time values ​​is established as a prediction model.

[0010] To solve the above technical problems, an embodiment of the present invention further provides a cracking time prediction device, comprising a processor, a memory, and a communication bus connecting the processor and the memory;

[0011] The memory stores the prediction model acquired by the cracking time prediction model acquisition method as described above;

[0012] The processor is used to call the cracking time prediction model according to the received value of the environmental parameter to be predicted of the injection molded product to be predicted, and output the predicted value of the cracking time of the injection molded product to be preset.

[0013] To solve the above technical problems, an embodiment of the present invention further provides a computer-readable storage medium, which stores the prediction model obtained by the cracking time prediction model acquisition method as described above; the prediction model can be called by a processor to output a corresponding cracking time prediction value.

[0014] The cracking time prediction model acquisition method, cracking time prediction device and medium provided in the embodiment of the present invention can obtain a first simulated application environment according to the actual application environment simulation setting of the injection molded product, based on the first cracking time value of the injection molded product (which can be but is not limited to the PC / ABS alloy injection molded product) cracking in the first simulated application environment, a tensile spline with the same material as the injection molded product is placed in the same first simulated application environment for a time reaching the first cracking time value to obtain the second fracture tensile parameter of the tensile spline, and determine the cracking judgment standard parameter v according to the first fracture tensile parameter of the tensile spline under the standard test environment; and then obtain at least two second simulated application environments according to the cracking judgment standard parameter v. The second cracking time value that reaches the cracking judgment standard parameter v in the environment is obtained, so that according to the obtained at least two pairs of application environment parameter values ​​and the second cracking time value, a curve equation of the application environment parameter value and the second cracking time value is established as a prediction model; the problem that the injection molded product cannot be used as a test tensile spline is effectively solved, and the problem that the tensile spline cannot restore the authenticity of the cracking of the injection molded product is also solved; the obtained prediction model can be directly used to predict the cracking time of the same injection molded product in different application environments without the need to re-execute the detection process, the detection is more intelligent and convenient, and the detection cost is lower and the efficiency is higher. At the same time, compared with the result of a single detection, the cracking time prediction value obtained by using the prediction model is also more accurate.

[0015] Other features and corresponding beneficial effects of the present invention are described in the latter part of the specification, and it should be understood that at least part of the beneficial effects become obvious from the description in the specification of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a process flow of a method for obtaining a cracking time prediction model provided in the first embodiment of the present invention;

[0017] Figure 2 A schematic diagram of a process for obtaining a first cracking time value provided in the first embodiment of the present invention;

[0018] Figure 3 A schematic diagram of a process flow of a cracking time prediction method provided in Embodiment 1 of the present invention;

[0019] Figure 4 A three-dimensional diagram of a PC / ABS alloy injection molding product provided in Example 2 of the present invention;

[0020] Figure 5 A front view of a PC / ABS alloy injection molding product provided in Example 2 of the present invention;

[0021] Figure 6 A schematic diagram of a first elongation at break ε1 curve provided in Example 2 of the present invention;

[0022] Figure 7 A schematic diagram of a second elongation at break ε2 curve provided in Example 2 of the present invention;

[0023] Figure 8 A schematic diagram of a time-temperature curve provided in Example 2 of the present invention;

[0024] Fig. 9 This is a schematic diagram of the structure of a cracking time prediction device provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the following is a further detailed description of the embodiments of the present invention through specific implementation methods combined with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Embodiment 1:

[0027] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and implementation examples.

[0028] In the related art, PC / ABS injection molding products cannot be used as test tensile specimens, and the test of a single tensile specimen cannot restore the authenticity of cracking of injection molding products. As a result, in the related art, the cracking time of PC / ABS injection molding products can only be tested on-site according to their actual application environment. When the application environment changes, they can only be completely retested, resulting in inconvenient testing, high testing costs, and low efficiency. The method provided in this embodiment can use the first cracking time value of the injection molded product cracking (i.e., cracking) in the first simulated application environment set according to the actual application environment as the setting time of the tensile spline in the first simulated application environment, and after the time of setting the tensile spline in the first simulated application environment reaches the first cracking time value, the second fracture tensile parameter measured and the first fracture tensile parameter obtained by the tensile spline under the standard test environment are used to determine the cracking judgment standard parameter v, and then obtain the second cracking time values ​​that reach the cracking judgment standard parameter v in at least two second simulated application environments, so as to establish a curve equation of the application environment parameter value and the second cracking time value as a prediction model based on the obtained at least two pairs of application environment parameter values ​​and second cracking time values; effectively solve the problem that the injection molded product cannot be used as a test tensile spline, and also solve the problem that the tensile spline cannot restore the authenticity of the cracking of the injection molded product; the obtained prediction model can be directly used to predict the cracking time of the same injection molded product in different application environments without the need to re-execute the detection process, the detection is more intelligent and convenient, and the detection cost is lower and the efficiency is higher. At the same time, compared with the result of a single detection, the cracking time prediction value obtained by using the prediction model is also more accurate.

[0029] It should be understood that the injection molded product in this embodiment may be, but is not limited to, a PC / ABS alloy injection molded product, or may be an injection molded product of other materials having similar rigidity properties to the PC / ABS alloy, such as a PE / ABS alloy material.

[0030] For ease of understanding, this embodiment is described below in conjunction with an exemplary method for obtaining a cracking time prediction model. Figure 1 As shown, it includes:

[0031] S101: Obtaining a first cracking time value of an injection molded product when cracks occur in a first simulated application environment. The first simulated application environment is obtained by simulating and setting an actual application environment of the injection molded product.

[0032] As described above, the injection molded product in this embodiment may be, but is not limited to, a PC / ABS alloy injection molded product, or may be an injection molded product made of other materials having similar rigidity properties to the PC / ABS alloy.

[0033] In this embodiment, the specific setting of the first simulated application environment can be simulated and set according to the actual application environment of the injection molding product. In this embodiment, when obtaining the first cracking time value of the injection molding product in the first simulated application environment, the time value of the first crack of the injection molding product in the first simulated application environment can be obtained, or the time value of K cracks of the injection molding product in the first simulated application environment can be obtained, where K can be greater than or equal to 2, and the specific value can be flexibly set according to specific application requirements.

[0034] Optionally, in this embodiment, in order to improve the accuracy of the first cracking time value obtained, the first cracking time value of the injection molded product to be tested that cracks in the first simulated application environment is obtained. For an example process, see Figure 2 As shown, it may include but is not limited to:

[0035] S201: placing at least two (e.g., 5, 10, or 15, etc., which can be flexibly set according to demand) injection molded products in a first simulated application environment.

[0036] S202: Obtaining time values ​​of cracks occurring in at least two injection molded products in a first simulated application environment, respectively.

[0037] S203: averaging the at least two acquired time values ​​to obtain a time average value, and using the obtained time average value as the first cracking time value; in this way, the first cracking time value obtained is more accurate and reliable.

[0038] S102: When the time for which the tensile spline is placed in the first simulated application environment reaches a cracking time value, a second fracture tensile parameter of the tensile spline is obtained.

[0039] In this embodiment, the material of the stretching spline is consistent with that of the injection molded product. For example, when the injection molded product is a PC / ABS alloy injection molded product, the stretching spline can also be made of the same PC / ABS alloy material. Optionally, the process of forming the stretching spline can also be consistent with that of the injection molded product. The stretching spline in this embodiment can be, but is not limited to, stretching splines from the same batch. In this embodiment, the obtained stretching spline and injection molded product can optionally be dried.

[0040] S103: Determine a cracking judgment standard parameter v according to the first fracture tensile parameter of the tensile spline under the standard test environment and the acquired second fracture tensile parameter.

[0041] The standard test environment in this embodiment can be flexibly set according to the adopted tensile test standard. The tensile test standard can also be flexibly set according to the specific application scenario, for example, it can adopt but not limited to GB / T1040.1-2006, GB / T1040.1-2018 or other test standards.

[0042] In addition, the first tensile strength at break parameter and the second tensile strength at break parameter in this embodiment can be flexibly selected as the tensile strength at break parameter, for example, elongation at break can be used but is not limited to it.

[0043] S104: Obtain second cracking time values ​​when the stretched spline reaches the cracking judgment standard parameter v in at least two second simulated application environments, where different second simulated application environments have different environmental parameter values, thereby obtaining at least two pairs of application environment parameter values ​​and second cracking time values.

[0044] It should be understood that the specific data volume of the second simulated application environment specifically used in this embodiment can be flexibly selected. For example, two, five, eight, ten, etc. can be set. The stretching splines set in different second simulated application environments are the same. And there are different environmental parameter values ​​between different second simulated application environments, and the different environmental parameter values ​​may include but are not limited to at least one of temperature values ​​or other parameter values. In this way, at least two pairs of application environment parameter values ​​and second cracking time values ​​can be obtained, for example, at least two pairs of temperature values ​​and second cracking time values ​​can be obtained.

[0045] S105: According to at least two pairs of application environment parameter values ​​and second cracking time values, a curve equation of the application environment parameter values ​​and the second cracking time values ​​is established as a prediction model.

[0046] It should be understood that, in this embodiment, when establishing the curve equation of the application environment parameter value and the second cracking time value according to two pairs of application environment parameter values ​​and the second cracking time value, the application environment parameter can be used as the value of the X-axis, and the second cracking time value can be used as the value of the Y-axis. According to multiple pairs of application environment parameter values ​​and the second cracking time value, multiple corresponding points can be obtained in the coordinate system composed of the X-axis and the Y-axis, and the multiple points are connected in sequence to obtain a curve, so as to establish the curve equation as a prediction model. When the prediction model is used for subsequent prediction, the corresponding environmental parameter value to be predicted is input, and the time when the environmental stress cracking of the injection molded product to be predicted occurs in the actual application environment corresponding to the environmental parameter value to be predicted can be calculated by equation fitting. Avoid the situation where the injection molded product is damaged and fails prematurely due to the failure to accurately predict the time of environmental stress cracking of the injection molded product, which causes huge economic losses and even threatens the safety of users.

[0047] Accordingly, an example of a method for predicting cracking time using the above prediction model is shown in Figure 3 As shown, including:

[0048] S301: Receive the predicted environmental parameter value of the injection molding product to be predicted. The injection molding product to be predicted here is the same as the injection molding product used when obtaining the above prediction model.

[0049] S302: Inputting the environmental parameter value to be predicted into the prediction model obtained by the above-mentioned cracking time prediction model acquisition method to obtain the cracking time prediction value of the injection molded product to be preset.

[0050] For ease of understanding, optionally, in an application scenario of this embodiment, an example is used to illustrate the determination of the cracking judgment standard parameter v using the first fracture tensile parameter and the second fracture tensile parameter as the first fracture elongation ε1 and the second fracture elongation ε2, respectively. In this example, the cracking judgment standard parameter v = (ε1-ε2) / ε1.

[0051] It should be understood that in order to improve the accuracy of the obtained second elongation at break ε2, multiple (at least two) tensile splines can be placed in the first simulated application environment and when the time reaches the first cracking time value, the fracture tensile parameters of the multiple tensile splines are obtained and averaged to obtain the second elongation at break ε2. Similarly, the first elongation at break ε1 can also be obtained in a similar manner to the second elongation at break ε2 to improve the accuracy of the first elongation at break ε1, which will not be repeated here.

[0052] Correspondingly, in this embodiment, obtaining the second cracking time value of the tensile spline reaching the cracking judgment standard parameter v in at least two second simulation application environments includes:

[0053] For a certain (that is, for each) second simulation application environment, the third fracture tensile parameter third fracture elongation ε3 of at least one tensile spline in the second simulation application environment is obtained by cumulative timing. When it is determined that (ε1-ε3) / ε1 falls within the range of (1-n1)*v to (1+n2)*v, it is determined that at least one tensile spline in the second simulation application environment reaches the cracking judgment standard parameter v, and the current timing value is obtained as the second cracking time value; the values ​​of n1 and n2 are greater than or equal to 0 and less than or equal to 1, for example, the values ​​of n1 and n2 can be greater than or equal to 0, less than or equal to 0.2, or greater than or equal to 0, less than or equal to 0.3, etc. And the values ​​of n1 and n2 can be the same or different. For example, n1 can be 0.05, n2 can be 0.1, or n1 can be 0.1, n2 can be 0.2, or n1 can be 0.1, n2 can be 0.15, etc.

[0054] For example, assuming that for a certain second simulation application environment, 50 stretching splines are set in the second simulation application environment, and the timing starts from time 0. When the timing value T1 is reached, 5 stretching splines are taken from them for tensile testing to obtain 5 elongations at break, and the average of these 5 elongations at break is taken as the third elongation at break ε3, and then it is determined whether (ε1-ε3) / ε1 falls within the range of (1-n1)*v to (1+n2)*v. If so, T1 is used as the second cracking time value; otherwise, the timing continues, and the above test judgment process is performed again after T1+△T, and it should be understood that in this embodiment, the value of △T can be fixed or dynamically changed. The time intervals of the timing detection adopted by different second simulation application environments can be the same or different, and can be flexibly set according to needs. For example, in one example, the values ​​of n1 and n2 can both be 0.1, and then it is determined whether (ε1-ε3) / ε1 falls within the range of 0.9*v to 1.1*v.

[0055] For ease of understanding, this embodiment is described below using an exemplary simulated application environment for ease of understanding.

[0056] In this application example, the first simulated application environment includes: a first environmental solution and a first environmental temperature value configured according to the actual application environment, and a mechanical stress structure applied to the injection molded product according to the environmental stress of the actual application environment; the composition of the first environmental solution can be flexibly set according to at least one of the specific material composition, the specific actual application environment, etc.; the first environmental temperature value can be flexibly set according to the specific material composition of the injection molded product, the specific actual application environment, etc.; the mechanical stress structure applied to the injection molded product can be flexibly set according to the total environmental stress of the specific actual application environment.

[0057] The second simulated application environment includes a second environmental solution and a second environmental temperature value. The second environmental solution is the same as the first environmental solution. The application environment parameter value is the second environmental temperature value. The second environmental temperature values ​​of different second simulated application environments are different, and the number of second environmental temperature values ​​(that is, the number of second simulated application environments) can also be flexibly set. For example, it can be set to but not limited to 5, 8, 10, 12, etc.

[0058] For example, in one application example, the injection molded product is a PC / ABS alloy injection molded product. The first environment solution included in the first simulated application environment may include but is not limited to a mixed solution of paraffin oil and dodecylbenzene in a set ratio. The specific ratio of paraffin oil and dodecylbenzene can be flexibly set according to the specific actual application environment. The first environment temperature value can be 90°C to 150°C, for example, the first environment temperature value can be 100°C. The second environment temperature value in the second simulated application environment can be set to 5, namely 50°C, 70°C, 90°C, 110°C, 130°C, etc.

[0059] It should be understood that the mechanical stress structure applied to the injection molded product in this embodiment can be flexibly set, for example, the injection molded product can be subjected to stress by bending. However, due to the poor control of the consistency of the curvature of different injection molded products, this method has the problem that the stress applied by bending of different injection molded products is inconsistent, which leads to the problem that the detection results are not accurate enough. In this regard, in this embodiment, stress is applied by stress holes set on the injection molded product and stress columns set in the stress holes. The consistency of this stress-applying structure is better controlled, which is convenient for applying the same stress to different injection molded products, thereby improving the accuracy of the detection results and the detection efficiency. In some application examples of this embodiment, the aperture d1 of the stress hole and the diameter d2 of the stress column can be set to satisfy: d1 = n3 * d2, the value of n3 is greater than or equal to 0.85 and less than or equal to 0.95. For example, the value of n3 can be 0.85, 0.88, 0.9, 0.92, 0.95, etc., which can be flexibly set according to needs.

[0060] In some examples of this embodiment, in order to further ensure the accuracy and reliability of the detection results, the stress holes provided on the injection molded product may at least meet at least one of the following conditions:

[0061] The stress holes opened on different injection molded products are the same, that is, the number and position of the stress holes opened on different injection molded products, as well as the hole diameters of the stress holes at the corresponding positions are the same;

[0062] The stress holes opened on the same injection-molded product have the same hole diameter; and optionally, the spacings between the stress holes opened on the same injection-molded product can be set to be the same.

[0063] Optionally, in some examples of this embodiment, the stress hole includes at least one of a screw hole and a pin hole, and the corresponding stress column is at least one of a screw and a pin. For example, in some application examples, all stress holes may be screw holes, and the corresponding stress column is a screw; in other application examples, all stress holes may be pin holes, and the corresponding stress column is a pin; in some application examples, some stress holes may be pin holes, some stress columns may correspond to pins, another part of stress holes may be screw holes, and another part of stress columns may be screws.

[0064] Optionally, in some examples of the present embodiment, in order to ensure the reliability of the test results, stress holes can be set to penetrate the thickness direction of the injection molded product; the ratio of the thickness of the injection molded product to the aperture of the stress hole is 0.08 to 0.16; for example, for an injection molded product with a thickness of 0.8 mm to 1.2 mm, the corresponding aperture of the stress hole can be 7.2 mm to 10.8 mm.

[0065] It can be seen that the method for obtaining the cracking time prediction model provided in this embodiment, and the method for predicting the cracking time using the obtained prediction model, simulate the actual application environment of the injection molded product, that is, external mechanical stress is applied and environmental solution is configured, effectively restoring the authenticity of the application scenario of the injection molded product.

[0066] The first cracking time of the injection molded product in the environmental solution is taken as the immersion time, and the corresponding quasi-tensile specimen is immersed in the same environmental solution for the first cracking time, and the measured elongation at break is used as reference data, which effectively solves the problem that the injection molded product cannot be used as a test tensile specimen, and the problem that the tensile specimen cannot restore the authenticity of the cracking of the injection molded product.

[0067] The elongation at break is used to characterize the cracking performance of the material, and based on the time-temperature equivalence principle, high temperature (such as the first ambient temperature value and the second ambient temperature value mentioned above) is used to accelerate the penetration of the environmental solution into the injection molded product, thereby establishing a prediction model for predicting the life span to estimate the service life of the injection molded product in actual application scenarios.

[0068] Embodiment 2:

[0069] For ease of understanding, this embodiment is based on the above embodiment and takes the injection molded product as a PC / ABS alloy injection molded product, and the corresponding tensile spline as a standard PC / ABS alloy tensile spline made according to the test standard (such as GB / T1040.1-2006, GB) as an example for explanation.

[0070] In this embodiment, the raw materials of PC / ABS alloy injection molding products are injection molded into a batch of uniform standard tensile specimens and injection molding products, and the tensile specimens and PC / ABS injection molding products are placed in a 60° C. to 100° C. oven for 4 to 12 hours for full drying;

[0071] According to the environmental conditions of the PC / ABS injection molding products (ie, the actual application conditions), a similar environmental simulation solution, ie, the first environmental solution, is configured.

[0072] Screw in the screw hole reserved for the PC / ABS injection molded product. The device thickness of 0.8mm to 1.5mm corresponds to a screw with an outer diameter of 10±2mm. The diameter of the screw hole is 90% of the outer diameter of the screw. It should be understood that this embodiment is not limited to the screw size and the stress application method; then immerse the PC / ABS injection molded product in the first environmental solution and place it under the first environmental temperature value, and record the time required for the first crack of the PC / ABS injection molded product; in this embodiment, 5 PC / ABS injection molded products can be tested under the same conditions, and their time t1, t2, t3, t4, t5 can be recorded, and finally the average value is obtained as the first cracking time value;

[0073] The tensile specimens are divided into two groups. One group of PC / ABS alloy tensile specimens is placed in a standard test environment (for example, a vacuum environment with an ambient temperature of 25°C) without any treatment; the other group of PC / ABS alloy tensile specimens is placed in a first environmental solution and under the first ambient temperature value, and the immersion time is the first cracking time value; then the tensile specimens are taken out and tested according to the GB / T1040.1-2006 test method, and the elongations at break of the two groups of specimens are recorded as ε1 and ε2; and the data is processed to obtain v=(ε1-ε2) / ε1.

[0074] According to the above method, a series of tensile specimens are placed in a second environmental solution (the same as the first environmental solution) and placed in ovens at different temperatures (i.e., different second temperature values) (i.e., a series of tensile specimens are placed in different second simulated application environments), and their tensile strain values ​​at break are tested regularly, and their elongation at break is recorded. When the elongation at break decreases by more than the above v value, the test is stopped, and the time to reach the v value is obtained, which is the second cracking time value γ;

[0075] After obtaining the second cracking time value γ under different second temperature conditions, the time-temperature curve is obtained with different second temperature values ​​as the horizontal coordinate and the second cracking time value γ as the vertical coordinate, and the curve equation is established as a prediction model; the time when environmental stress cracking occurs in PC / ABS alloy injection molding products in actual application scenarios can be calculated through equation fitting.

[0076] For ease of understanding, this example is described below using two specific application scenarios.

[0077] Application scenario 1:

[0078] Prepare 5 PC / ABS alloy specific product samples (i.e. PC / ABS alloy injection molding products), clean them with dry paper towels, and put them in an oven at 80±2℃ to dry for later use; For PC / ABS alloy specific product samples, please refer to Figure 4 and Figure 5 As shown, its thickness T1 is 1.5 mm, length L is 100 mm, and width W is 20 mm;

[0079] A first environmental solution of the application environment of the PC / ABS alloy injection molding product is prepared. The first environmental solution prepared by this method is prepared by paraffin oil and dodecylbenzene in a mass ratio of 9:1, and is shaken for 5 minutes to mix evenly;

[0080] An example method of applying external stress to PC / ABS alloy injection molded products is to screw a screw into the stress hole reserved in the PC / ABS alloy injection molded product, and the diameter of the stress hole is 90% of the outer diameter of the screw; for example, see Figure 5 As shown, the diameter d of the stress hole is 6mm, and the spacing P between the stress holes is 20mm. In this application scenario, the device thickness of 0.8mm to 1.2mm corresponds to a screw with an outer diameter of 10±2mm. Soak the stress hole with the screw in the first environmental solution and place it in an oven at 100°C. Start timing and record the time required for the first crack to appear on 5 PC / ABS alloy injection molded products. Calculate the average time required for cracks to appear on the 5 products as the first cracking time value. If the time exceeds 360 hours and the PC / ABS alloy injection molded product has not cracked, it is regarded as an environmental stress cracking resistant product;

[0081] PC / ABS alloy pellets were injected into tensile specimens using an injection molding machine according to GB / T17037.1-1997 standard, and the tensile specimens were divided into two groups, with 5 specimens in each group. The first group was placed in a standard test environment without any treatment, and the second group was immersed in the first environmental solution and placed in a 100°C oven. The immersion time was the first cracking time value, that is, the tensile specimens were taken out after the first cracking time value;

[0082] The two groups of tensile splines were tested for their tensile strain at break according to GB / T1040.1-2006. Five elongations at break were obtained for each group, and the average values ​​were taken and recorded as ε1 (for the first group of tensile splines) and ε2. The values ​​of ε1 and ε2 refer to Figure 6 and Figure 7As shown. Let v = (ε1-ε2) / ε1. The significance of v is that when the elongation at break of the PC / ABS alloy injection molded product decreases by a percentage greater than or equal to v after being immersed in the first environmental solution, it indicates that the device has cracked.

[0083] PC / ABS alloy pellets are injected into 5 groups of tensile specimens using an injection molding machine according to GB / T17037.1-1997 standard, with the number of specimens in each group being not less than 30. One group is placed in a second environmental solution, and then placed in ovens at different temperatures, with a temperature gradient (i.e., the gradient of the second environmental temperature value) of 60°C, 80°C, 90°C, 100°C, and 120°C. To ensure the accuracy of the prediction, the temperature gradient points are not less than 5, and samples are taken regularly to test the elongation at break, with the number of samples taken in each group being 5 each time. The average value of the elongation at break of each group of 5 is calculated and recorded as the third elongation at break ε3, and the time required for (ε1-ε3) / ε1 to drop to the v value ±10%v is finally recorded, which is recorded as the second cracking time value tv;

[0084] With the second ambient temperature value as the horizontal coordinate X and the second cracking time value tv as the vertical coordinate Y, plot the points and use the corresponding fitting algorithm to fit the above coordinate points to obtain the time-temperature curve, establish the curve equation, and stipulate that its variance shall not be less than 0.9, as the prediction model;

[0085] When predicting, input the actual temperature of the actual usage scenario of the PC / ABS alloy injection molding product to be predicted, and calculate the predicted time of environmental stress cracking at the actual temperature based on the curve equation obtained previously, so as to estimate the service life of the PC / ABS alloy injection molding product.

[0086] Application scenario 2:

[0087] Prepare 5 PC / ABS alloy specific product samples (i.e. PC / ABS alloy injection molding products), clean them with dry paper towels, and put them in an oven at 80±2℃ to dry for 2h for later use;

[0088] A first environmental solution of the application environment of the PC / ABS alloy injection molding product is prepared. The first environmental solution prepared by this method is prepared by paraffin oil and dodecylbenzene in a mass ratio of 8.5:1.5, and is shaken for 6 minutes to mix evenly;

[0089] An example method of applying external stress to PC / ABS alloy injection molded products is to screw a screw into the stress hole reserved in the PC / ABS alloy injection molded product, and the diameter of the stress hole is 90% of the outer diameter of the screw; for example, see Figure 5As shown, the diameter d of the stress hole is 6mm, and the spacing P between the stress holes is 20mm. In this application scenario, the device thickness of 0.8mm to 1.2mm corresponds to a screw with an outer diameter of 10±2mm. Soak the stress hole with the screw in the first environmental solution and place it in an oven at 100°C. Start timing and record the time required for the first crack to appear on 5 PC / ABS alloy injection molded products. Calculate the average time required for cracks to appear on the 5 products as the first cracking time value. Assume that the first cracking time value obtained in this experiment is 32h (h); if the time exceeds 360 h and the PC / ABS alloy injection molded product has not cracked, it is regarded as an environmental stress cracking resistant product;

[0090] PC / ABS alloy pellets were injected into tensile specimens using an injection molding machine according to GB / T17037.1-1997 standard, and the tensile specimens were divided into two groups, with 5 specimens in each group. The first group was placed in a standard test environment without any treatment, and the second group was immersed in the first environmental solution and placed in a 100°C oven. The immersion time was the first cracking time value, that is, the tensile specimens were taken out after immersion for 32 hours;

[0091] The two groups of tensile splines were tested for their tensile strain at break according to GB / T1040.1-2006. Five elongations at break were obtained for each group. The average values ​​were taken and recorded as ε1 (for the first group of tensile splines) and ε2, and v = (ε1-ε2) / ε1. Assume that ε1 is 84.3%, ε2 is 19.8%, and v is 76.5% in this test;

[0092] PC / ABS alloy pellets are injection molded into 5 groups of tensile specimens using an injection molding machine according to GB / T17037.1-1997 standard, with the number of specimens in each group not less than 30. One group is placed in a second environmental solution and then placed in ovens at different temperatures. The temperature gradient (i.e., the gradient of the second environmental temperature value) is: 60°C, 80°C, 90°C, 100°C, and 120°C. To ensure the accuracy of the prediction, the temperature gradient points are not less than 5, and samples are taken regularly to test their elongation at break. The number of samples in each group is 5 each time. The average value of the elongation at break of each group of 5 is calculated and recorded as the third elongation at break ε3. Finally, the time required for (ε1-ε3) / ε1 to drop to the v value ±10%v is recorded as the second cracking time value tv. In this test, at 60℃, 80℃, 90℃, 100℃, and 120℃, tv is 1680h, 200h, 72h, 32h, and 12h respectively.

[0093] Take the soaking temperature as the horizontal axis X and tv as the vertical axis Y, and plot the points. Please refer to Figure 8As shown. Use Excel software to fit the above coordinate points, obtain the time-temperature curve, establish the curve equation, and stipulate that its variance must not be less than 0.9. The coordinate points obtained in this test are (60,1680), (80,200), (90,72), (100,32), (120,12), and the curve equation obtained by fitting is Y=4*1017*X-8.058, and the variance R2 is 0.9969;

[0094] When predicting, the actual temperature of the actual use scenario of the PC / ABS alloy injection molding product to be predicted is input, and the predicted time of environmental stress cracking at the actual temperature is deduced according to the curve equation Y=4*1017*X-8.058, and the experiment ends. In this experiment, the actual temperature is assumed to be 40°C, and the time for environmental stress cracking of the PC / ABS alloy injection molding product to occur is 49278h, about 5.6 years. It can be seen that the prediction model acquisition method provided by this embodiment, and the prediction method of cracking time using the prediction model, both simulate the actual application environment of the injection molding product and effectively restore the authenticity of the application scenario of the injection molding product; at the same time, the first cracking time of the injection molding product in the environmental solution is used as the immersion time, and the corresponding quasi-tensile spline is immersed in the same environmental solution for the first cracking time, and the measured elongation at break is used as the reference data, which effectively solves the problem that the injection molding product cannot be used as a test tensile spline, and the tensile spline cannot restore the authenticity of the cracking of the injection molding product. In addition, the elongation at break is used to characterize the cracking performance of the material, and based on the principle of time-temperature equivalence, high temperature is used to accelerate the penetration of environmental solutions into injection molded products, thereby establishing a prediction model for predicting life to estimate the service life of injection molded products in actual application scenarios.

[0095] Embodiment three:

[0096] This embodiment also provides a cracking time prediction device, see Fig. 9 As shown, it includes a processor 901, a memory 902 and a communication bus 903 connecting the processor 901 and the memory 902;

[0097] The memory 902 stores the prediction model obtained by the cracking time prediction model acquisition method shown in the above embodiments. The processor is used to call the cracking time prediction model according to the received environmental parameter value of the injection molded product to be predicted, and output the cracking time prediction value of the injection molded product to be preset.

[0098] This embodiment further provides a computer-readable storage medium, which stores the prediction model obtained by the method for obtaining the cracking time prediction model as described above; the prediction model can be called by a processor to output a corresponding cracking time prediction value.

[0099] The computer-readable storage medium in this embodiment includes volatile or non-volatile, removable or non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, computer program modules or other data). Computer-readable storage media include, but are not limited to, RAM (Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable read only memory), flash memory or other memory technology, CD-ROM (Compact Disc Read-Only Memory), digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer.

[0100] This embodiment also provides a computer program (or computer software) for implementing the above-mentioned prediction model. The computer program can be distributed on a computer-readable medium and executed by a computing device to implement the steps in the cracking time prediction method as described above; and in some cases, at least one of the steps shown or described can be executed in an order different from that described in the above embodiment.

[0101] This embodiment further provides a computer program product, including a computer readable device, on which any computer program as shown above is stored. In this embodiment, the computer readable device may include the computer readable storage medium as shown above.

[0102] It can be seen that those skilled in the art should understand that all or some of the steps, systems, and functional modules / units in the above disclosed methods can be implemented as software (which can be implemented with computer program code executable by a computing device), firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component can have multiple functions, or a function or step can be performed by several physical components in cooperation. Some or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit.

[0103] In addition, it is well known to those skilled in the art that communication media generally contain computer readable instructions, data structures, computer program modules or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery media. Therefore, the present invention is not limited to any specific hardware and software combination.

[0104] The above contents are further detailed descriptions of the embodiments of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for obtaining a cracking time prediction model, characterized in that: include: Obtaining a first cracking time value of the injection molded product when cracks occur in a first simulated application environment, wherein the first simulated application environment is obtained by simulating and setting the actual application environment of the injection molded product; When the time for placing the tensile spline in the first simulated application environment reaches the first cracking time value, obtaining a second fracture tensile parameter of the tensile spline, wherein the material of the tensile spline is consistent with that of the injection molded product; Determining a cracking judgment standard parameter v according to the first fracture tensile parameter of the tensile spline under the standard test environment and the obtained second fracture tensile parameter; Obtaining the second cracking time values ​​of the stretched spline reaching the cracking judgment standard parameter v in at least two second simulated application environments, wherein different second simulated application environments have different environmental parameter values, thereby obtaining at least two pairs of application environment parameter values ​​and second cracking time values; According to the at least two pairs of application environment parameter values ​​and the second cracking time values, a curve equation of the application environment parameter value and the second cracking time value is established as a prediction model; The first tensile strength at break parameter and the second tensile strength at break parameter are respectively a first elongation at break ε1 and a second elongation at break ε2; The crack judgment standard parameter v = (ε1-ε2) / ε1; The obtaining of the second cracking time value of the tensile spline reaching the cracking judgment standard parameter v in at least two second simulation application environments comprises: For a certain second simulation application environment, a third fracture tensile parameter and a third fracture elongation ε3 of at least one tensile spline in the second simulation application environment are obtained by cumulative timing. When (ε1-ε3) / ε1 falls within the range of (1-n1)*v to (1+n2)*v, it is determined that the at least one tensile spline in the second simulation application environment reaches the cracking judgment standard parameter v, and the current timing value is obtained as the second cracking time value; the values ​​of n1 and n2 are greater than or equal to 0 and less than or equal to 1.

2. The method for obtaining a cracking time prediction model according to claim 1, wherein: The step of obtaining a first cracking time value of the injection molded product when cracking occurs in the first simulated application environment comprises: placing at least two of the injection molded products in the first simulated application environment; Respectively obtaining the time values ​​of cracking of the at least two injection-molded products in the first simulated application environment; The at least two acquired time values ​​are averaged to obtain a time average value, and the time average value is used as the first cracking time value.

3. The method for obtaining a cracking time prediction model according to any one of claims 1 or 2, characterized in that: The first simulated application environment includes: a first environmental solution and a first environmental temperature value configured according to the actual application environment, and a mechanical stress structure applied to the injection molded product according to the environmental stress of the actual application environment; The second simulated application environment includes a second environmental solution and a second environmental temperature value. The second environmental solution is the same as the first environmental solution. The application environment parameter value is the second environmental temperature value. The second environmental temperature value of the second simulated application environment is different.

4. The method for obtaining a cracking time prediction model according to claim 3, wherein: The injection molded product is a polycarbonate and acrylonitrile-butadiene-styrene copolymer and a mixture PC / ABS alloy injection molded product, and the first environmental solution includes a mixed solution prepared by paraffin oil and dodecylbenzene in a set ratio.

5. The method for obtaining a cracking time prediction model according to claim 3, characterized in that: The mechanical stress structure applied to the injection molded product includes: The stress hole provided on the injection molded product and the stress column provided in the stress hole, the aperture d1 of the stress hole and the diameter d2 of the stress column satisfy: d1=n3*d2, and the value of n3 is greater than or equal to 0.85 and less than or equal to 0.

95.

6. The method for obtaining a cracking time prediction model according to claim 5, characterized in that: The stress holes opened on different injection molded products are the same; and / or, The stress holes opened on the same injection molded product have the same hole diameter.

7. A cracking time prediction device, characterized in that: comprising a processor, a memory and a communication bus connecting the processor and the memory; The memory stores a prediction model acquired by the method for acquiring a cracking time prediction model according to any one of claims 1 to 6; The processor is used to call the cracking time prediction model according to the received environmental parameter value of the injection molded product to be predicted, and output the cracking time prediction value of the injection molded product to be predicted.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a prediction model acquired by the method for acquiring a cracking time prediction model according to any one of claims 1 to 6; the prediction model can be called by a processor to output a corresponding cracking time prediction value.

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