Method for analyzing the most difficult vulcanization point of thick rubber articles

Abstract

The present application provides a kind of method for analyzing the most difficult vulcanization point of thick rubber product, first measure the size of thick rubber product and mould etc. and draw three-dimensional model combination entity, three-dimensional model combination entity is imported into thermal analysis software, confirm the material attribute of each part of thick rubber product, query its corresponding thermal conductivity information, and give it to corresponding division part, after grid division is carried out to three-dimensional model combination entity, set parameter, then run thermal analysis software, carry out steady-state thermal analysis simulation and transient thermal analysis simulation in turn, finally obtain the position of the most difficult vulcanization point of the thick rubber product through the simulation time-three-dimensional temperature nephogram obtained by analysis. The present application simulates the actual production process of thick rubber product by using thermal analysis software, not only low cost, and simulation operation process is simple, running time is short, the most difficult vulcanization point of thick rubber product can be quickly analyzed through simulation calculation result.

Description

Technical Field

[0001] This invention relates to the field of rubber product manufacturing technology, specifically to a method for analyzing the most difficult vulcanization point of thick rubber products. Background Technology

[0002] In mining equipment, using wear-resistant rubber as a material can improve the equipment's wear resistance and extend its service life. Because mining equipment is generally large, its rubber spare parts are often thick and irregularly shaped, and some products even have metal skeletons, making it difficult to estimate their vulcanization time during production. When estimating vulcanization time based on experience, to avoid losses due to incomplete vulcanization of thick rubber products, more time is usually allowed to ensure complete internal vulcanization. This leads to excessively long vulcanization times when producing new types of thick rubber products, resulting in lower production efficiency. Furthermore, vulcanization equipment, environment, and mold structure design all affect the actual vulcanization temperature, leading to inconsistent quality even for the same thick rubber product with the same vulcanization time. During vulcanization, the vulcanization pressure on the thick rubber product does not fluctuate significantly, but because rubber is a poor conductor of heat, its internal temperature distribution is uneven. Therefore, by identifying the most difficult vulcanization point of thick rubber products and measuring its temperature in real time to determine the equivalent vulcanization time, the vulcanization time can be flexibly adjusted. This allows for improved production efficiency of thick rubber products while ensuring vulcanization quality, thereby increasing equipment utilization, reducing production costs, saving energy, and enhancing the overall benefits of the enterprise.

[0003] In existing technologies, the simplest method to determine the location of the lowest internal temperature point, i.e., the most difficult vulcanization point, in thick rubber products is the bubble point method. However, due to the wide variety of types and shapes of thick rubber products, and even in cases with a metal skeleton, the bubble point method is costly and difficult to implement. Therefore, there is a need for a low-cost method that can quickly determine the most difficult vulcanization point of thick rubber products, and thereby rapidly calculate the equivalent vulcanization time. Summary of the Invention

[0004] The purpose of this invention is to provide a method for analyzing the most difficult vulcanization point of thick rubber products, which solves the technical problems of high cost and difficulty in implementation of the bubble method in the prior art, and achieves the technical effect of low cost and easy implementation, which can quickly determine the most difficult vulcanization point of thick rubber products.

[0005] To achieve the above objectives, the present invention proposes the following technical solution:

[0006] A method for analyzing the most difficult vulcanization point of thick rubber products includes the following steps:

[0007] Step 1: Measure the actual dimensions of the thick rubber product to obtain the actual dimensions of the thick rubber product, which includes a rubber part and a metal skeleton, with the metal skeleton built into the rubber part;

[0008] Measure the actual dimensions of the mold and its matching inserts and positioning pins to obtain the actual dimensions of the mold, the inserts, and the positioning pins;

[0009] The mold is a molding mold used in conjunction with the actual production of the thick rubber product;

[0010] Step 2: Based on the actual dimensions of the thick rubber product, create a three-dimensional model of the thick rubber product.

[0011] Based on the actual dimensions of the mold, draw a three-dimensional model of the mold.

[0012] Based on the actual dimensions of the insert, draw a three-dimensional model entity of the insert;

[0013] Based on the actual dimensions of the positioning pin, draw a three-dimensional model of the positioning pin.

[0014] The three-dimensional model entities of the thick rubber product, the mold, the insert, and the positioning pin are combined together to obtain a three-dimensional model assembly entity.

[0015] Step 3: Import the three-dimensional model combination entity into the thermal analysis software. Then, divide the three-dimensional model combination entity into several parts according to different material properties and name them respectively. After the material properties are divided, add the label corresponding to its material properties to each part of the three-dimensional model combination entity after the material properties are divided.

[0016] Step 4: Based on the material properties of each part of the three-dimensional model composite entity after the material property division is completed, enter the corresponding thermal conductivity information of the material, and assign the thermal conductivity information to each part of the three-dimensional model composite entity after the material property division with the corresponding label;

[0017] Step 5: In the thermal analysis software, set the face-to-face contact between every two parts of the three-dimensional model assembly after material property division to "bonded", and adjust "Pinball Region" to "Auto Detection Value" so that the thermal analysis software automatically adjusts the value of "Pinball Region" to ensure that the value of "Pinball Region" is always less than the unit mesh size set in the next step; or, manually adjust the value of "Pinball Region" to adapt to the unit mesh size set in the next step.

[0018] Step Six: Use the meshing function of the thermal analysis software to mesh each part of the three-dimensional model assembly entity after the material property division is completed;

[0019] Step 7: Import the meshed 3D model assembly into the steady-state thermal analysis module of the thermal analysis software. Based on the temperature of the rubber part, the metal skeleton, the mold, the insert, and the positioning pin before the actual production of the rubber thick product, apply a constant thermal load to each corresponding part of the meshed 3D model assembly. Simultaneously, run the steady-state thermal analysis calculation to obtain the steady-state thermal analysis calculation results.

[0020] Step 8: Import the combined 3D model entity after mesh generation and the steady-state thermal analysis calculation results into the transient thermal analysis module of the thermal analysis software, and use the steady-state thermal analysis calculation results as the initial temperature setting conditions for the transient thermal analysis;

[0021] Step 9: In the transient thermal analysis module, a constant thermal load is applied to the upper surface of the upper mold cover and the lower surface of the lower mold cover of the three-dimensional model assembly entity after meshing, and its temperature is set to the process temperature set by the vulcanizing machine during the actual production of the rubber thick product.

[0022] Thermal convection loads are applied to the other surfaces of the three-dimensional model composite entity after the meshing is completed. The air temperature value, heat transfer coefficient and transient thermal analysis simulation running time are set, and the time node is defined as "time".

[0023] Set automatic time step to "No", and set the time step value as needed;

[0024] Set time integration to "On";

[0025] After the settings are completed, run the transient thermal analysis module of the thermal analysis software to start the solution;

[0026] After the solution is completed, the transient thermal analysis calculation results are obtained;

[0027] Step 10: Take several time points of the transient thermal analysis simulation running time and draw a simulation time-three-dimensional temperature cloud map for the rubber part of the rubber thick product;

[0028] The time axis of the simulated time-3D temperature cloud map is adjusted to the time node corresponding to the actual production process time of the rubber thick product, thus obtaining a 3D temperature cloud map of the rubber part of the rubber thick product. Using an isosurface view, the temperature scale is adjusted to determine the position of the lowest rubber temperature point. The position of the lowest rubber temperature point is then sectioned, and the temperature display accuracy of the temperature scale is modified to 0.1℃, so that a precise temperature valley appears in the isosurface view. This temperature valley is the most difficult vulcanization point of the rubber part.

[0029] As a preferred technical solution of the present invention, the three-dimensional model entities of the rubber thick product, the mold, the insert, and the positioning pin in step two are all CAD three-dimensional model entities.

[0030] As a preferred embodiment of the present invention, in step three, the three-dimensional model assembly is imported into thermal analysis software, and then the three-dimensional model assembly is divided into several parts according to different material properties and named accordingly, including:

[0031] The three-dimensional model assembly was imported into the thermal analysis software. Then, the three-dimensional model assembly was divided into four parts according to different material properties and named accordingly:

[0032] The upper mold cover, lower mold cover, and outer frame of the mold are named "outside mold".

[0033] The insert and the locating pin are named "insidemould";

[0034] The rubber portion of the thick rubber product is further divided according to the type of rubber and named as "corresponding rubber grade + rubber".

[0035] The metal skeleton is further divided according to the different materials of the metal skeleton, and named as "corresponding metal skeleton material + skeleton" respectively;

[0036] After the material properties are defined, a label corresponding to the material properties is added to each part of the three-dimensional model composite entity after the material properties are defined.

[0037] As a preferred embodiment of the present invention, in step five, the size of the unit grid is set as follows: the upper mold cover, lower mold cover and outer frame of the mold > the insert and the positioning pin > the rubber part of the rubber thick product = the metal skeleton.

[0038] As a preferred embodiment of the present invention, step six, which involves using the mesh generation function of the thermal analysis software to mesh each part of the three-dimensional model composite entity after the material property division is completed, includes:

[0039] For the upper mold cover, lower mold cover and outer frame of the mold, the Hex Dominant mesh generation method is used and its "Element Order" is set to "linear". If the Hex Dominant mesh generation fails, the three-dimensional model combination entity is readjusted, and the three-dimensional model combination entity is split or merged to make it into a regular convex body. The split parts are connected with each other using bonded.

[0040] For the insert and the locating pin, the Automatic meshing method is used, and its "ElementOrder" is set to "Quadratic" to reduce calculation errors;

[0041] For the rubber portion of the thick rubber product, regardless of its regularity, its mesh division method is forced to Tetrahedrons, and its "Element Order" is set to "Quadratic".

[0042] For the metal skeleton, the Tetrahedrons mesh partitioning method is used, and its "Element Order" is set to "Quadratic".

[0043] In a preferred embodiment of the present invention, the air temperature setting value in step nine is 30°C.

[0044] In a preferred embodiment of the present invention, in step nine, the heat transfer coefficient is set to 0.0000015 W / mm. 2 ·℃.

[0045] As a preferred technical solution of the present invention, in step nine, the transient thermal analysis simulation running time is set to be 1800s longer than the actual production time of the rubber thick product, or 3600s longer than the inferred vulcanization time.

[0046] As a preferred technical solution of the present invention, in step nine, the time step value is set to 180s to 300s for the actual production time of the rubber thick product, and only the location of the most difficult vulcanization point needs to be solved.

[0047] For cases where the vulcanization time needs to be determined, the time step is set to 60 seconds.

[0048] As a preferred embodiment of the present invention, for cases where it is necessary to determine the vulcanization time, step eleven is further included:

[0049] A temperature data table of the lowest temperature point of the rubber portion of the thick rubber product is derived from the transient thermal analysis calculation results. All items below 90°C are removed from the data table. All remaining items are then processed in a spreadsheet using the following formula:

[0050]

[0051] In the above formula, T s The cumulative equivalent vulcanization time, x is the corresponding term number, Δt is the set time step, E is the activation energy of the rubber material, R is the gas constant, and T is the time step. n Let T be the temperature at the nth term. n-1 T0 is the temperature of the preceding term of the nth term, and T0 is the temperature corresponding to the calculated equivalent vulcanization time.

[0052] By calculating the cumulative equivalent vulcanization time for each item, when it reaches the equivalent vulcanization time set for demolding during the actual production of the rubber thick product, the time corresponding to that item is the estimated vulcanization time.

[0053] The method for analyzing the most difficult vulcanization point of thick rubber products provided by this invention first involves drawing a three-dimensional model of the thick rubber product and mold as a complete set. This three-dimensional model replaces the actual physical assembly of the thick rubber product and mold in production. Then, the three-dimensional model is imported into thermal analysis software, where material properties are defined and meshes are created. Next, based on the parameters set during actual production of the thick rubber product, corresponding parameters are set in the thermal analysis software to ensure that the simulated vulcanization process closely approximates the actual vulcanization process. This guarantees that the calculated results are close to the actual production results and have high accuracy. Finally, by analyzing the simulation results from the thermal analysis software—that is, the variation of vulcanization temperature over time at various parts of the thick rubber product during the entire simulated vulcanization process—the locations of the highest and lowest temperature points of the thick rubber product can be qualitatively and quickly analyzed. The location of the lowest temperature point is the location of the most difficult vulcanization point.

[0054] Therefore, by using simulation thermal analysis software, the three-dimensional model of the thick rubber product is set according to the parameters in actual production, and the actual production process of the thick rubber product is simulated. Compared with the existing technology, it is not only cheaper and can be repeated multiple times, but also has a simple simulation operation process and short running time. The most difficult vulcanization point of the thick rubber product can be quickly analyzed through simulation calculation results.

[0055] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other.

[0056] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0057] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0058] Figure 1 This is a three-dimensional view of the simulated time-three-dimensional temperature cloud map of the thick rubber product of Embodiment 1 of the present invention;

[0059] Figure 2 This is a cross-sectional view of the simulated time-three-dimensional temperature cloud map of the thick rubber product of Embodiment 1 of the present invention;

[0060] Figure 3 This is a longitudinal cross-sectional view of the simulated time-three-dimensional temperature cloud map of the thick rubber product of Embodiment 1 of the present invention;

[0061] Figure 4 This is a schematic diagram comparing the positions of simulated holes and empirical holes in a thick rubber product according to Embodiment 1 of the present invention;

[0062] Figure 5 This is a comparison diagram of the temperature changes of simulated holes and empirical holes in the rubber thick product of Embodiment 1 of the present invention during actual production.

[0063] Figure 6 This is a graph showing the variation of the highest and lowest temperatures of the thick rubber product in Example 2 of the present invention.

[0064] Figure 7This is a cumulative equivalent vulcanization time curve of the thick rubber product of Example 2 of the present invention;

[0065] Figure 8 This is a simulated time-three-dimensional temperature cloud map of the thick rubber product of Embodiment 2 of the present invention. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art.

[0067] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, wholes, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or collections thereof. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0068] A method for analyzing the most difficult vulcanization point of thick rubber products includes the following steps:

[0069] Step 1: Measure the actual dimensions of the thick rubber product to obtain the actual dimensions of the thick rubber product. The thick rubber product includes a rubber part and a metal skeleton, wherein the metal skeleton is built into the rubber part. Therefore, the actual dimensions of the thick rubber product actually include the actual dimensions of the rubber part and the actual dimensions of the metal skeleton.

[0070] Measure the actual dimensions of the mold and its matching inserts and locating pins to obtain the actual dimensions of the mold, inserts, and locating pins.

[0071] The mold is a molding mold used in conjunction with the actual production of the thick rubber product.

[0072] Step 2: Based on the actual dimensions of the rubber product, draw a three-dimensional model of the rubber product. This three-dimensional model includes a three-dimensional model of the rubber part and a three-dimensional model of the metal skeleton. Since the metal skeleton is built into the rubber part, the three-dimensional model of the metal skeleton is also built into the three-dimensional model of the rubber part in the three-dimensional model of the rubber product.

[0073] Draw a three-dimensional model of the mold based on its actual dimensions;

[0074] Draw a 3D model of the inlay based on its actual dimensions;

[0075] Draw a 3D model of the locating pin based on its actual dimensions;

[0076] The three-dimensional model entities of the thick rubber product, the mold, the insert, and the positioning pin are combined together to obtain a three-dimensional model assembly entity. Specifically, the three-dimensional model entities are assembled according to the actual installation and assembly method of the thick rubber product, mold, insert, and positioning pin during the production of the thick rubber product, so as to make the three-dimensional model assembly entity similar to the assembled object and ensure high accuracy of the calculation results.

[0077] In addition, during the drawing process, it is also necessary to ensure that the obtained 3D model entities of thick rubber products and 3D model entities of molds are consistent with their corresponding physical objects, so as to ensure that the 3D model combination entities used for calculation are consistent with the physical objects and to ensure that the results obtained by simulation analysis using thermal analysis software are highly accurate.

[0078] Furthermore, CAD drawing software is used to draw the three-dimensional model entities. Therefore, the three-dimensional model entities of the rubber thick product, the mold, the insert, and the positioning pin in step two are all CAD three-dimensional model entities.

[0079] Step 3: Import the three-dimensional model assembly into the thermal analysis software. To facilitate parameter setting and export / analysis of subsequent calculation results in subsequent steps, the three-dimensional model assembly is then divided into several parts according to different material properties and named accordingly. After the material properties are divided, a label corresponding to the material properties is added to each part of the three-dimensional model assembly after the material properties are divided, so as to facilitate parameter setting and export or call of subsequent calculation results.

[0080] Furthermore, in step three, the three-dimensional model assembly is imported into the thermal analysis software. Then, the three-dimensional model assembly is divided into several parts according to different material properties and named accordingly, including:

[0081] The 3D model assembly is imported into the thermal analysis software. The 3D model assembly is then divided into four parts based on different material properties and named accordingly:

[0082] The upper mold cover, lower mold cover, and outer frame of the mold are named "outside mold".

[0083] The insert and the locating pin are named "insidemould";

[0084] The rubber portion of the thick rubber product is further divided according to the type of rubber and named as "corresponding rubber grade + rubber".

[0085] The metal skeleton is further divided according to the different materials of the metal skeleton, and named as "corresponding metal skeleton material + skeleton" respectively;

[0086] After the material properties are defined, a label corresponding to the material properties is added to each part of the three-dimensional model composite entity after the material properties are defined.

[0087] Step 4: Based on the material properties of each part of the three-dimensional model combination entity after the material properties have been divided, enter the corresponding thermal conductivity information of the material, such as the thermal conductivity information of the rubber part of the rubber product, the thermal conductivity information of the metal skeleton, the thermal conductivity information of the mold, etc., and assign the thermal conductivity information to each part of the three-dimensional model combination entity after the material properties have been divided and has the corresponding label.

[0088] Step 5: Since the gaps between the various components of the mold cannot be measured accurately in actual measurements, to reduce calculation failures caused by errors between the 3D model assembly and the actual assembly, the contact between the surfaces of every two parts in the 3D model assembly is set to "bonded" in the thermal analysis software, and "Pinball Region" is adjusted to "Auto Detection Value" so that the thermal analysis software automatically adjusts the value of "Pinball Region" to ensure that the value of "Pinball Region" is always less than the unit mesh size set in the next step; or, the value of "Pinball Region" can be manually adjusted to adapt to the unit mesh size set in the next step.

[0089] Step Six: Use the meshing function of the thermal analysis software to mesh each part of the three-dimensional model assembly entity after the material properties have been defined.

[0090] Furthermore, to adapt to the thermal analysis calculation results of the thermal analysis software, in step six, the meshing function of the thermal analysis software is used to mesh each part of the three-dimensional model composite entity after the material property division is completed, including:

[0091] For the upper mold cover, lower mold cover and outer frame of the mold, the Hex Dominant mesh generation method is used and its "Element Order" is set to "linear" to make the thermal analysis calculation stable and consume less memory. If the Hex Dominant mesh generation fails, the three-dimensional model combination entity is readjusted, that is, the three-dimensional model combination entity is split or merged to make it into a regular convex body, and the split parts are connected with the bonded parts.

[0092] For the inserts and other components such as the locating pins, the Automatic meshing method is used. Due to the relatively complex structure of this part, its "ElementOrder" is set to "Quadratic" to reduce calculation errors.

[0093] For the rubber portion of the thick rubber product, regardless of its regularity, its mesh division method is forced to Tetrahedrons, and its "ElementOrder" is set to "Quadratic". Because the mesh division cannot be infinitely small and the internal structure of the rubber portion is irregular, an irregular mesh division method is adopted. In the final analysis, the most difficult vulcanization point of the thick rubber product can be determined by taking the geometric center of its isotherms.

[0094] Similarly, for the metal skeleton, the Tetrahedrons meshing method is used, and its "ElementOrder" is set to "Quadratic" to reduce overall calculation errors.

[0095] Furthermore, the size of the unit grid is set as follows: upper mold cover, lower mold cover and outer frame of the mold > insert and positioning pin > rubber part of the rubber thick product = metal skeleton. That is, the focus is on making the rubber thick product into a very fine grid, while other parts (such as the mold) can be made into a coarser grid. The focus is on the rubber thick product itself to save the computing power of the thermal analysis software and reduce calculation errors, while reducing the difficulty of analysis.

[0096] While the initial temperature can be set when configuring material parameters, in most cases, even the same material will have different temperatures in different locations. Therefore, this embodiment first imports the three-dimensional model assembly into the steady-state thermal analysis module of the thermal analysis software. Based on the temperature of each part before the actual production of the thick rubber product, a constant thermal load is applied to the corresponding parts of the three-dimensional model assembly, acting on the entire three-dimensional model assembly. See step seven for details.

[0097] Step 7: Import the meshed 3D model assembly into the steady-state thermal analysis module of the thermal analysis software. Based on the temperature conditions of the rubber portion, metal skeleton, mold, insert, and positioning pin before actual production of the thick rubber product, apply a constant thermal load to each part of the meshed 3D model assembly. Simultaneously, run the steady-state thermal analysis calculation to obtain the results. With a constant thermal load applied to all parts of the 3D model assembly, the steady-state thermal analysis result will necessarily show that the temperature of all the partitioned parts within the 3D model assembly corresponds to the set thermal load temperature of each part of the assembled object. Therefore, this temperature can be used as the initial temperature condition for each part in the transient thermal analysis module.

[0098] Step 8: Import the assembled 3D model after mesh generation and the steady-state thermal analysis results into the transient thermal analysis module of the thermal analysis software, and use the steady-state thermal analysis results as the initial temperature setting conditions for the transient thermal analysis. The initial temperature here includes the initial temperature of the rubber portion of the thick rubber product, the initial temperature of the metal skeleton, and the initial temperature of the mold, etc.

[0099] Step 9: Since the vulcanizing machine heats the upper surface of the upper mold cover and the lower surface of the lower mold cover during the actual production of thick rubber products, in the transient thermal analysis module, a constant thermal load is applied to the upper surface of the upper mold cover and the lower surface of the lower mold cover of the three-dimensional model combination entity after the mesh division is completed, and its temperature is set to the process temperature set by the vulcanizing machine during the actual production of the thick rubber products.

[0100] Thermal convection loads are applied to the other surfaces of the three-dimensional model composite entity after meshing (i.e., the upper surface of the upper mold cover and the lower surface of the lower mold cover, excluding the upper surface of the upper mold cover and the lower surface of the lower mold cover). The air temperature value, heat transfer coefficient and transient thermal analysis simulation running time are set, and the time node is defined as "time".

[0101] Set automatic time step to "No", and set the time step value as needed;

[0102] Set time integration to "On";

[0103] After setting up, run the transient thermal analysis module of the thermal analysis software to start the solution;

[0104] After the solution is completed, the transient thermal analysis calculation results are obtained.

[0105] Specifically, the air temperature is set at 30℃;

[0106] The heat transfer coefficient is set to 0.0000015 W / mm. 2 ·℃;

[0107] The transient thermal analysis simulation running time is set to be 1800s longer than the actual production time of the rubber thick product, or 3600s longer than the roughly estimated vulcanization time.

[0108] For the actual production process time of the rubber thick product, and only the location of the most difficult vulcanization point needs to be solved, the time step value is set to 180s~300s.

[0109] For cases where the vulcanization time needs to be determined, the time step is set to 60 seconds.

[0110] Step 10: Take several time points of the transient thermal analysis simulation run time and draw a simulation time-three-dimensional temperature cloud map for the rubber part of the rubber thick product;

[0111] The time axis of the simulated time-3D temperature cloud map is adjusted to be near the time node corresponding to the actual production process time of the thick rubber product, thus obtaining a 3D temperature cloud map of the rubber part of the thick rubber product. Using an isosurface view, the temperature scale is adjusted to roughly determine the location of the lowest rubber temperature point. The location of the lowest rubber temperature point is then sectioned, and the temperature display accuracy of the temperature scale is modified to 0.1℃, making the temperature display accuracy of the lowest temperature point 0.1℃. This facilitates the differentiation of two lowest temperature points with similar temperature values, thereby more accurately finding the location of the lowest temperature point. This results in a precise temperature valley appearing in the isosurface view, making it easier to find the location of the lowest temperature point. The temperature valley is the most difficult vulcanization point of the rubber part of the thick rubber product.

[0112] Step 11: For cases where the vulcanization time needs to be determined,

[0113] A temperature data table of the lowest temperature point of the rubber portion of the thick rubber product was derived from the transient thermal analysis calculation results. All items below 90°C were removed from the data table, and all remaining items were placed in a spreadsheet for calculation using the following formula:

[0114]

[0115] In the above formula, T s The cumulative equivalent vulcanization time is given by x, the corresponding term number, Δt, the set time step, E, the activation energy of the rubber material, R, and the gas constant. n Let T be the temperature at the nth term. n-1 T0 is the temperature of the preceding term of the nth term, and T0 is the temperature corresponding to the calculated equivalent vulcanization time.

[0116] By calculating the cumulative equivalent vulcanization time for each item, when it reaches the equivalent vulcanization time set for demolding during the actual production of thick rubber products, the time corresponding to that item is the estimated vulcanization time.

[0117] The method for analyzing the most difficult vulcanization point of thick rubber products provided by this invention first involves drawing a three-dimensional model of the thick rubber product and mold as a complete set. This three-dimensional model is then used to replace the actual combination of the thick rubber product and mold in production. Thermal analysis software is used to simulate the vulcanization process of the three-dimensional model, i.e., to simulate the vulcanization process of the combined object in actual production. The simulation results are used to analyze the temperature change patterns of various parts of the thick rubber product, qualitatively identifying the parts of the thick rubber product that have been heated the most and least (the parts with the highest and lowest temperatures). A simulation time-three-dimensional temperature cloud map of the rubber part is then drawn. Finally, based on the simulation time-three-dimensional temperature cloud map, the lowest temperature point of the thick rubber product, i.e., the most difficult vulcanization point, is determined.

[0118] Therefore, by using simulation thermal analysis software and setting parameters in actual production, the actual production process of thick rubber products can be simulated. Compared with existing technologies, this method is not only cheaper and allows for repeated simulations, but also has a simpler operation process and shorter running time. The most difficult vulcanization point of thick rubber products can be quickly analyzed through simulation calculation results.

[0119] Furthermore, the calculation results from thermal analysis software can quantitatively obtain numerical curves showing the temperature changes of various parts of thick rubber products over time. Based on this, the location of the most difficult vulcanization point (the part with the lowest heating history) of the thick rubber product can be easily determined, and the temperature change curve of that part can be obtained. According to this curve, the equivalent vulcanization time of that part of the rubber material can be quickly calculated. Then, based on the production experience of similar thick rubber products, the time when the bubble point appears in the product can be quickly determined. The time when the bubble point appears in the thick rubber product can be found through only one or two tests, thereby determining the vulcanization time of the thick rubber product. This greatly shortens the number and time of process tests for thick rubber products, significantly improves product development efficiency, and saves development costs.

[0120] Example 1

[0121] Analyze and determine the location of the most difficult vulcanization point for thick rubber products.

[0122] This invention relates to the production of feed end liners for a 6.2m overflow ball mill. Traditionally, the most difficult vulcanization point is determined by the geometric center (center of gravity) of a three-dimensional model of a thick rubber product. Similarly, in this embodiment, the most difficult vulcanization point of the feed end liner is its geometric center (center of gravity). However, this embodiment uses thermal analysis software for simulation and analyzes the simulation results to determine the location of the most difficult vulcanization point of the feed end liner.

[0123] First, following steps one and two above, create relatively accurate 3D models of the feed end liner, the mold, inserts, and locating pins used in its production, using CAD software. Then, assemble these 3D models according to actual production conditions to obtain a combined 3D model. Import this combined model into thermal analysis software. Following steps three and four above, use the material assignment function of the thermal analysis software to assign materials to all geometric entities within the combined 3D model. Finally, following steps five and six above, use the meshing function of the thermal analysis software to mesh the combined 3D model to varying degrees and in different ways based on its material properties and geometric complexity.

[0124] Then, following the steps in step seven above, the three-dimensional model assembly is imported into the steady-state thermal analysis module of the thermal analysis software. Based on the temperature of the rubber part, metal skeleton, mold, insert and positioning pin of the actual production feed end liner, a constant thermal load is applied to each part of the three-dimensional model assembly, and steady-state thermal analysis calculation is run to obtain the steady-state thermal analysis calculation results.

[0125] Next, following steps eight to nine above, the three-dimensional model assembly is imported into the transient thermal analysis module of the thermal analysis software. Based on the steady-state thermal analysis calculation results, the initial temperature of the rubber part of the feed end liner is set to 90℃, the initial temperature of the metal skeleton is set to 45℃, and the initial temperature of the mold is set to 100℃. The boundary conditions for the transient thermal analysis of the three-dimensional model assembly are set, specifically, the upper surface of the upper mold cover and the lower surface of the lower mold cover are set to the process temperature set by the vulcanizing machine, i.e., 143℃. Thermal convection loads are applied to the other surfaces of the three-dimensional model assembly, with the air temperature set to 30℃ and the heat transfer coefficient set to 0.0000015w / mm. 2•℃, the transient thermal analysis simulation running time is set to be 1800s longer than the actual production process time of thick rubber products, or 3600s longer than the roughly estimated vulcanization time. In this application, the transient thermal analysis simulation running time is set to 19200s; the time node is defined as "time".

[0126] Set the automatic time step to "No", and set the time step value as needed. Specifically, for the actual production process time of the rubber thick product, and only the location of the most difficult vulcanization point needs to be solved, set the time step value to 180s~300s.

[0127] Set time integration to "On";

[0128] After setting up, run the transient thermal analysis module of the thermal analysis software to start the solution;

[0129] After the solution is completed, the transient thermal analysis calculation results are obtained.

[0130] Finally, following the steps in step ten above, several time points of the transient thermal analysis simulation run time are selected, and a simulation time-three-dimensional temperature cloud map is plotted on the rubber portion of the thick rubber product to obtain the following result: Figure 1 The simulated time-3D temperature contour plot is shown.

[0131] At 19200s, the simulated time-3D temperature contour plots of the feed end liner at different angles are shown below. Figure 2 and Figure 3 As shown, the highest temperature is 143℃, located on the upper and lower surfaces of the feed end liner; the lowest temperature is 128.02℃, located at the center of the feed end liner, biased towards the inner arc side of the feed end liner. The position of the lowest temperature point was mapped onto the 3D model assembly and marked as the most difficult vulcanization point before opening the mold. The opening position obtained by thermal software analysis simulation (simulated hole) was compared with the opening position based on the geometric center (empirical hole). Figure 4 As shown.

[0132] The simulated holes obtained through thermal software analysis were put into actual production and compared with the temperature measurement results of empirical holes based on the geometric center. Figure 5As shown, the initial temperature of both the simulated hole and the empirical hole is 84℃. After 50 minutes of vulcanization of the thick rubber product, a temperature difference appears between the simulated hole and the empirical hole, specifically, the temperature of the empirical hole is higher than that of the simulated hole. At 339 minutes of vulcanization, the temperature of the empirical hole is 125℃, while the temperature of the simulated hole is 120℃, indicating that the heating rate of the empirical hole is faster than that of the simulated hole during vulcanization. The equivalent vulcanization time is 1256s for the empirical hole and 896s for the simulated hole, a difference of 360s. When automatic demolding is performed according to the set equivalent vulcanization time of 1200s for the empirical hole, the equivalent vulcanization time of the simulated hole is 861s, which is just over the bubble point of the NP-01 rubber. Therefore, through actual temperature measurement comparison, the simulated hole obtained by the method of this application embodiment has high accuracy. Furthermore, compared with the prior art, it has the advantages of low cost and ease of implementation.

[0133] Example 2

[0134] Determine the vulcanization time for thick rubber products.

[0135] The cylinder lifting bars for producing a 6.1×6.4 semi-autogenous mill are 300mm thick and have an irregular shape.

[0136] To determine the most difficult vulcanization point of the cylinder lifting strip, thermal analysis software was used to perform a thermal analysis on the entire assembly, including the strip and its mold. First, steps one through seven were performed as described above. Then, the initial temperature of the rubber portion of the cylinder lifting strip was set to 90℃, the initial temperature of the metal frame to 45℃, and the initial temperature of the mold to 100℃. The transient thermal analysis simulation time was set to 36000s, resulting in temperature data curves for the entire cylinder lifting strip, including the temperature change curves at the highest and lowest temperatures, and the average temperature change curve. Figure 6 As shown. For Figure 6 After removing items below 90℃, the value at the lowest temperature (i.e., the value on curve G) is placed in a spreadsheet for calculation using the following formula:

[0137]

[0138] Obtain the equivalent vulcanization time-time curve, such as Figure 7 As shown. The equivalent vulcanization time for demolding is set to 800s. Substituting this into the equivalent vulcanization time-time curve above, the theoretical equivalent vulcanization time for demolding is obtained as 20460s. During this time period, the simulated time-3D temperature cloud map of the entire cylinder lifting strip is analyzed. Then, a cross-section is taken at the location of its lowest temperature, as shown... Figure 8As shown. Since the most difficult vulcanization point of this thick rubber product is located on its center line, an opening can be made at any position on the center line so that the thermocouple can reach that position.

[0139] In actual production, the equivalent vulcanization time for demolding was set to 710s. After the thick rubber product was demolded, a drill was used to sample the location of its most difficult vulcanization point. Small air bubbles were found in the samples, indicating that the location was not yet fully vulcanized. The equivalent vulcanization time for demolding was then changed to 850s. After demolding, another sample was taken, and the location of the most difficult vulcanization point was no longer found to contain air bubbles. Random sampling was then performed on other locations of the thick rubber product, and no air bubbles were found. Therefore, it can be concluded that setting the equivalent vulcanization time for the most difficult vulcanization point of the cylindrical lifting strip to approximately 850s is sufficient to achieve complete vulcanization of the thick rubber product.

[0140] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method of analyzing the most difficult point of vulcanization of a thick rubber article, characterized in that, It comprises the following steps: Step one: measuring the actual size of the rubber thick product, obtaining the actual size of the rubber thick product, the rubber thick product comprising a rubber part and a metal framework, the metal framework being built in the rubber part; Measuring the actual size of the mold, the insert block and the positioning pin matched with the mold, obtaining the actual size of the mold, the actual size of the insert block and the actual size of the positioning pin; Wherein, the mold is a forming mold matched with the actual production of the rubber thick product; Step two: according to the actual size of the rubber thick product, drawing the rubber thick product three-dimensional model entity of the rubber thick product; According to the actual size of the mold, draw the mold three-dimensional model entity of the mold; According to the actual size of the insert block, draw the insert block three-dimensional model entity of the insert block; According to the actual size of the positioning pin, draw the positioning pin three-dimensional model entity of the positioning pin; The rubber thick product three-dimensional model entity, the mold three-dimensional model entity, the insert block three-dimensional model entity and the positioning pin three-dimensional model entity are matched and combined together to obtain a three-dimensional model combined entity; Step three: importing the three-dimensional model combined entity into the thermal analysis software, then dividing the three-dimensional model combined entity into several parts according to the different material properties and naming them respectively, and adding the corresponding label of the material property to each part of the three-dimensional model combined entity after the material property division is completed; Step four: according to the material property of each part of the three-dimensional model combined entity after the material property division is completed, input the thermal conductivity information of the corresponding material, and assign the thermal conductivity information to each part of the three-dimensional model combined entity after the material property division is completed which has the corresponding label; Step five: in the thermal analysis software, set the contact between the surfaces of each two parts in the three-dimensional model combined entity after the material property division is completed as "bonded", adjust "Pinball Region" to "AutoDetection Value" to let the thermal analysis software automatically adjust the value of "Pinball Region", so as to ensure that the value of "Pinball Region" is less than the size of the unit grid set in the next step under any condition; or manually adjust the value of "Pinball Region" to adapt to the size of the unit grid set in the next step; Step six: using the grid division function of the thermal analysis software to divide each part of the three-dimensional model combined entity after the material property division is completed into grids; Step seven: importing the three-dimensional model combined entity after the grid division is completed into the steady-state thermal analysis module of the thermal analysis software, applying constant thermal load to each part of the three-dimensional model combined entity after the grid division is completed according to the temperature condition of the rubber part, the metal framework, the mold, the insert block and the positioning pin before the actual production of the rubber thick product, acting on the whole three-dimensional model combined entity after the grid division is completed, at the same time, running steady-state thermal analysis calculation to obtain the steady-state thermal analysis calculation result; Step eight: import the three-dimensional model assembly entity after grid division and the steady-state thermal analysis calculation results into the transient thermal analysis module of the thermal analysis software, and set the steady-state thermal analysis calculation results as the initial temperature setting conditions of the transient thermal analysis; Step nine: in the transient thermal analysis module, apply a constant thermal load to the upper surface of the upper mold cover and the lower surface of the lower mold cover of the three-dimensional model assembly entity after grid division, and set the temperature to the process temperature set by the vulcanizing machine during actual production of the rubber thick product; Apply a heat convection load to other surfaces of the three-dimensional model assembly entity after grid division, set the air temperature value, heat exchange coefficient and transient thermal analysis simulation running time, and set the time node definition as "time"; Set the automatic time step to "no", and set the time step value as needed; Set the time integration to "on"; After the setting is completed, run the transient thermal analysis module of the thermal analysis software to start solving; After the solving is completed, the transient thermal analysis calculation results are obtained; Step ten: take several time nodes of the transient thermal analysis simulation running time to draw a simulated time-three-dimensional temperature cloud map of the rubber part of the rubber thick product; Adjust the time axis of the simulated time-three-dimensional temperature cloud map to the time node corresponding to the determined process time during actual production of the rubber thick product to obtain a three-dimensional temperature cloud map of the rubber part, use an isosurface view, adjust the temperature scale, determine the position of the lowest rubber temperature point, perform view cutting on the position of the lowest rubber temperature point, modify the temperature display precision of the temperature scale to 0.1℃, so that an accurate temperature valley appears in the isosurface view, and the temperature valley is the most difficult vulcanization point of the rubber part.

2. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, characterized by The three-dimensional model entity of the rubber thick product, the three-dimensional model entity of the mold, the three-dimensional model entity of the insert block and the three-dimensional model entity of the positioning pin in step two are CAD three-dimensional model entities.

3. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, characterized by In step three, after the three-dimensional model assembly entity is imported into the thermal analysis software, the three-dimensional model assembly entity is divided into several parts according to different material properties and is named respectively, including: Import the three-dimensional model assembly entity into the thermal analysis software, and then divide the three-dimensional model assembly entity into four parts according to different material properties and name them respectively, specifically: For the upper mold cover, the lower mold cover and the outer frame of the mold, name it as "outside mould"; For the insert block and the positioning pin, name it as "inside mould"; For the rubber part of the rubber thick product, further divide it according to different rubber types, and name it as "corresponding rubber brand + rubber" respectively; For the metal skeleton, further divide it according to different materials of the metal skeleton, and name it as "corresponding metal skeleton material + skeleton" respectively; After the material property division is completed, add a label corresponding to the material property of each part of the three-dimensional model assembly entity after the material property division.

4. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, characterized by In the fifth step, the size of the unit grid is set to the upper mold cover, lower mold cover and outer frame of the mold > the insert and the positioning pin > the rubber part of the rubber thick product = the metal skeleton.

5. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, and In the sixth step, the grid division function of the thermal analysis software is used to divide the grid for each part of the three-dimensional model assembly entity after the material attribute division, including: ​ For the upper mold cover, lower mold cover and outer frame of the mold, the Hex Dominant grid division method is used, and the "Element Order" is set to "linear". If the Hex Dominant grid generation fails, the three-dimensional model assembly entity is re-adjusted, and the three-dimensional model assembly entity is split or merged to become a regular convex polyhedron. The split parts are connected using a bonded connection. For the insert and the positioning pin, the Automatic grid division method is used, and the "Element Order" is set to "Quadratic" to reduce the calculation error. For the rubber part of the rubber thick product, whether it is regular or not, the grid division method is forced to be Tetrahedrons, and the "Element Order" is set to "Quadratic". For the metal skeleton, the Tetrahedrons grid division method is used, and the "Element Order" is set to "Quadratic".

6. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, characterized by In the ninth step, the air temperature value is set to 30℃.

7. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, and In the ninth step, the heat transfer coefficient is set to 0.0000015w / mm²·℃. ​ 8. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, and In the ninth step, the transient thermal analysis simulation running time is set to be 1800s longer than the process time of the actual production of the rubber thick product, or 3600s longer than the inferred curing time. ​ 9. The method of claim 1, wherein the most difficult point of vulcanization of a thick rubber article is analyzed, and In the ninth step, for the process time determined by the actual production of the rubber thick product, and only the position of the most difficult curing point needs to be solved, the time step value is set to 180s~300s. ​ For the case where the curing time needs to be solved, the time step is set to 60s.

Images