Carbon fiber composite autoclave molding method for rail control console

Abstract

The present application belongs to the technical field of composite autoclave molding, and relates to a rail console carbon fiber composite autoclave molding method. The present application sets an elastic pressure compensation pad in the thickness mutation area, embeds a thermocouple, carries out local thermal compensation on the negative deviation area based on the maximum temperature deviation during the heating stage, and reduces the heating rate to convergence; calculates the real-time viscosity curve based on the resin curing kinetics model, and carries out the pressing operation when the viscosity is locally minimized and the deviation converges; dynamically adjusts the medium flow of each independent temperature control loop in the holding and cooling stage to minimize the uniformity deviation of the temperature field; and the demolding operation is conditioned by the overall temperature change rate approaching zero and the highest temperature being lower than the real-time glass transition temperature. The present application solves the problems of temperature field unevenness, resin curing asynchronization and pressure mismatch caused by thickness mutation, so as to eliminate temperature difference, inhibit the warping deformation of the component, reduce the defects of porosity and delamination, and improve the molding precision.

Description

Technical Field

[0001] This invention belongs to the field of composite material autoclave molding technology, and relates to a method for molding a carbon fiber composite autoclave for a track control console. Background Technology

[0002] The track control console is mostly made of carbon fiber composite material and integrally formed by autoclave process. Its structure includes operating table, side wall, mounting groove and reinforcing ribs, and there are many areas where the material thickness changes abruptly.

[0003] In existing autoclave molding processes, the entire part is typically heated, with a uniform heating program set based on the internal atmosphere temperature. During this heating process, the heat medium transfers heat to the part through the mold, initiating resin curing. Sudden thickness changes result in differences in heat capacity and heat transfer paths between thick and thin areas, leading to asynchronous heat absorption and exothermic reactions. Thin areas heat up faster than thick areas, creating a dynamic temperature gradient within the part. This temperature inconsistency causes the resin to reach the viscous flow state, gel point, and glass transition at different times in different areas, resulting in varying curing shrinkage states. In autoclave molding, this can easily cause warping and uneven interlayer bonding, affecting the shape and positional accuracy and reliability of the molded part.

[0004] Pressurization is a crucial step in autoclave molding to eliminate porosity and control fiber volume content. The pressurization timing typically corresponds to a stage where resin viscosity is relatively low. Current processes often rely on preset autoclave temperatures or curing times for pressurization. However, due to these temperature differences within the part, resin viscosity changes asynchronously in different areas. The pressurization timing determined by a single parameter may misalign with the actual rheological state of the resin in certain regions. Pressurizing after some areas have entered the gel stage weakens the porosity-eliminating effect; pressurizing prematurely while some areas still have high resin viscosity can cause uneven resin flow. These situations can increase the likelihood of defects such as porosity, dry spots, or delamination in autoclaved components. Summary of the Invention

[0005] In view of this, in order to solve the problems mentioned in the background art, a method for molding carbon fiber composite materials in an autoclave for track control consoles is proposed.

[0006] The objective of this invention can be achieved through the following technical solution: a method for molding carbon fiber composite material in a thermostatic tank for a track controller, comprising: S1, laying carbon fiber prepreg in a mold, setting an elastic pressure compensation pad in the thickness abrupt change zone, embedding a thermocouple, covering with a vacuum bag, sealing and evacuating the vacuum, and then placing it in a thermostatic tank.

[0007] S2. During the curing and heating stage, collect the temperature of each thermocouple and calculate the average temperature. The temperature with the largest absolute value of the difference between each temperature and the average temperature is the maximum temperature deviation. When the deviation of the thermocouple with a temperature lower than the average temperature constitutes the maximum temperature deviation and increases continuously, perform local thermal compensation on the corresponding area. If the deviation change rate is still positive after compensation, reduce the overall heating rate of the autoclave until convergence.

[0008] S3. Calculate the real-time viscosity curve based on the temperature of each thermocouple and the resin curing kinetic model. When the curve drops to a local minimum point and the maximum temperature deviation change rate converges, execute the pressurization operation.

[0009] S4. During the heat preservation, curing and cooling stages, calculate the average absolute value of the temperature difference between each thermocouple and the average temperature as the temperature field uniformity deviation, and dynamically adjust the flow rate of the heating or cooling medium in each independent temperature control circuit with the goal of minimizing this deviation.

[0010] S5. When the overall temperature change rate approaches zero and the highest temperature is lower than the glass transition temperature of the current material, perform the demolding operation.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention calculates the maximum temperature deviation and the rate of change to perform local thermal compensation and reduces the heating rate to convergence. In the heat preservation and cooling stages, the flow rate of the heating or cooling medium is dynamically adjusted with the goal of minimizing the temperature field uniformity deviation. This solves the problem of asynchronous heat absorption and reaction heat release in the thickness change area, which causes dynamic temperature gradient inside the part. This achieves the effect of eliminating temperature differences so that the resin in each area can enter the viscous flow state, gel point and glass transition synchronously, suppress the warping deformation of the component and improve the uniformity of interlayer bonding.

[0012] (2) The present invention uses the temperature of each thermocouple combined with the real-time viscosity curve as a dual criterion to perform pressurization operation, and uses the curve falling to the local minimum point and the maximum temperature deviation change rate converging as a dual criterion. This solves the problem of misalignment between the pressurization time determined by a single tank temperature or curing time and the actual rheological state of the local resin. It achieves the effect of accurately matching the actual rheological state of the local resin in each region, effectively eliminating pores within the optimal flow window period, and avoiding dry spots or delamination defects. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart of the carbon fiber composite material autoclave molding method for the track controller console in this invention;

[0015] Figure 2 This is a flowchart illustrating the specific content of step S3 in this invention;

[0016] Figure 3 This is a flowchart illustrating the specific content of step S5 in this invention. Detailed Implementation

[0017] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The specific scheme of the carbon fiber composite autoclave molding method for the track controller provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Please see Figure 1 As shown, the implementation of this invention includes S1 to S5: For the autoclave molding of carbon fiber composite material for a track control console, the first step is to complete the prepreg laying and vacuum sealing, followed by heating, heat preservation and curing, cooling and demolding processes. During this process, due to the presence of areas with abrupt thickness changes such as the interface between the control panel and the side wall, the grooves or bosses for installing control elements, and the lower reinforcing ribs, problems such as uneven temperature distribution, asynchronous resin curing process, and internal stress concentration can easily occur.

[0021] To address the aforementioned issues, this invention utilizes an elastic pressure compensation pad combined with multi-zone independent temperature-controlled thermocouple monitoring to construct a temperature deviation-driven local thermal compensation system with adaptive linkage of heating rate, thereby suppressing temperature divergence. Simultaneously, a curing kinetic model is introduced to calculate resin viscosity, using the minimum viscosity point and the convergence of the temperature deviation rate as dual criteria to achieve coordinated decision-making on pressurization timing. During the heat preservation and cooling stages, minimizing temperature field uniformity deviation is the objective. The flow rate of heating or cooling media in each zone is dynamically adjusted based on the direction and magnitude of the deviation, and the adjustment amplitude is automatically optimized according to the deviation trend, forming a closed-loop control for uniformity. Finally, the current glass transition temperature is calculated in real-time based on the cumulative heat history of curing to determine safe demolding conditions. This method, through precise zoned control of independent temperature control loops and dynamic determination of the glass transition temperature related to the degree of curing, ensures that resin flow and curing are synchronized in areas of abrupt thickness changes, effectively suppressing interlayer defects and residual stress, ultimately improving the dimensional stability and mechanical performance consistency of the track control console components.

[0022] S1. Lay carbon fiber prepreg in the mold, set elastic pressure compensation pads in the thickness change area, embed thermocouples, cover with vacuum bag, seal and evacuate, and then place in a thermostatic tank.

[0023] Typically, track control console components have areas of abrupt thickness changes, such as the interface between the control panel and side panels, the mounting groove and boss area, and the reinforcing rib area. During autoclave curing, these areas are prone to resin flow obstruction, fiber volume fraction fluctuations, and weak interfacial bonding due to differences in heat conduction paths and uneven pressure transmission. Therefore, it is necessary to pre-set pressure compensation and temperature monitoring mechanisms during the installation stage to provide a data basis for subsequent temperature field control and pressurization timing determination.

[0024] In one specific embodiment, the operator first lays the carbon fiber prepreg layer by layer on the surface of the cleaned mold cavity, following the layup sequence determined in the layup design document, for example, using a symmetrical and balanced stacking combination of [45° / 0° / -45° / 90°], repeating this four-layer sequence until the target thickness is reached. During each layer laying process, a roller press is used to roll and press the layers to remove air between them.

[0025] Subsequently, elastic pressure compensation pads are laid in the thickness abrupt change areas of the track control console. These thickness abrupt change areas include: the junction area between the control panel and the side wall, the groove or boss area on the control panel for installing control components, and the reinforcing rib area under the control panel. The elastic pressure compensation pads are made of high-temperature resistant silicone rubber, with a thickness of 0.8 to 1.2 times the thickness difference between adjacent areas. They are cut and adapted according to the geometry and thickness difference of the corresponding areas to ensure they are in contact with the carbon fiber prepreg.

[0026] When the carbon fiber prepreg has been laid to one-third to one-half of the total number of layers, for example, if the total number of layers is 24, then the thermocouple temperature probe is embedded in a specific interlayer location between layers 8 and 12. This specific interlayer location includes areas of abrupt thickness changes, corner areas, and the center of the plane. High-temperature resistant tape is used to secure the thermocouple cable to the surface of adjacent prepreg layers to prevent displacement.

[0027] After the installation and embedding are completed, release cloth and breathable felt are sequentially covered on the surface of the component. A vacuum bag film is then used to completely cover the entire surface, and sealing strips are used to adhere the vacuum bag film to the mold at its edges. A vacuum is then created by drawing a vacuum through the vacuum interface, ensuring the vacuum bag film adheres tightly to the component to form a vacuum chamber. Vacuuming continues until the negative pressure value is determined based on previous process verification tests and the pressure bearing limit of the vacuum bag film. The chamber is then left to stand under pressure to confirm that there is no leakage.

[0028] Finally, the lead wires of the thermocouple are led out through the special sealing joint on the vacuum bag and connected to the control system of the autoclave. The autoclave is equipped with multiple independent temperature control loops. The spatial partitions of the multiple independent temperature control loops correspond one-to-one with the positions of the thermocouples pre-embedded on the mold. Each loop covers one or more thickness change areas, corner areas, or plane center areas. The partitioning method is calibrated by thermal simulation. Each independent temperature control loop includes an independent heating medium pipe, a cooling medium pipe, and a flow control valve.

[0029] The encapsulation assembly, which includes the mold, carbon fiber prepreg, elastic pressure compensation pad, thermocouple, release cloth, breathable felt, and vacuum bag film, is placed into the autoclave.

[0030] S2. During the curing and heating stage, collect the temperature of each thermocouple and calculate the average temperature. The temperature with the largest absolute value of the difference between each temperature and the average temperature is the maximum temperature deviation. When the deviation of the thermocouple with a temperature lower than the average temperature constitutes the maximum temperature deviation and increases continuously, perform local thermal compensation on the corresponding area. If the deviation change rate is still positive after compensation, reduce the overall heating rate of the autoclave until convergence.

[0031] During the autoclave curing and heating stage, due to the influence of hot air convection inside the autoclave, the thermal inertia of the mold, and the complex geometry of the component itself, the heating rate and instantaneous temperature vary in different areas, leading to a continuous increase in the maximum temperature deviation. This can cause premature resin curing or localized overheating, affecting the final component's mechanical properties and internal quality. Traditional single PID control cannot handle complex local temperature difference problems. Therefore, this step uses multi-point feedback active local thermal compensation and global heating rate coordinated adjustment to ensure the uniformity of the temperature field throughout the heating stage.

[0032] In one specific embodiment, during the curing and heating stage, the temperature of each thermocouple is synchronously collected according to a set collection cycle, such as once every 10 to 30 seconds. Based on the temperature, the arithmetic mean of all thermocouples is calculated as the average temperature, and the absolute value of the difference between each thermocouple temperature and the average temperature is calculated. The largest absolute value is taken as the maximum temperature deviation.

[0033] Using the average temperature as the reference temperature, the deviation of each thermocouple temperature from the reference temperature is calculated. A positive deviation indicates that the temperature at that point is higher than the average temperature, and a negative deviation indicates that the temperature is lower than the average temperature. When any deviation is negative, and the absolute value of the negative deviation constitutes the maximum temperature deviation, and the value of the maximum temperature deviation increases monotonically within a continuously set number of sampling cycles (e.g., 3 to 5 consecutive cycles), it indicates that there is a significant thermal hysteresis phenomenon in the mold area, forming local cold spots, and the uniformity of the global temperature field is continuously deteriorating. Simply relying on the overall heating of the medium inside the autoclave can no longer compensate for the heat absorption gap in this area. In this case, the mold area number corresponding to the thermocouple with the negative deviation is retrieved, and the output power of the independent temperature control loop corresponding to that number is increased for local thermal compensation.

[0034] Conversely, when all deviations are positive or zero, or when the maximum temperature deviation does not increase monotonically, it indicates that there are no continuously deteriorating local cold spots in the temperature field. In this case, the overall heating strategy of the autoclave is maintained, and the output power of each independent temperature control loop is no longer increased. For independent temperature control loops that have performed local thermal compensation, when the temperature deviation in their corresponding area changes from negative to zero or positive, or when the rate of change of the maximum temperature deviation is less than or equal to zero, the output power of that independent temperature control loop is stopped from increasing.

[0035] After performing local thermal compensation, the rate of change of the maximum temperature deviation is obtained by calculating the difference between the maximum temperature deviation of the current acquisition cycle and the previous acquisition cycle and dividing it by the acquisition cycle time interval. If the rate of change is positive, it means that the local thermal compensation power is not enough to offset the thermal hysteresis effect in the region. Then, the heating rate of the autoclave is gradually reduced according to a preset step size, such as decreasing by 0.2℃ / min each time, until the rate of change of the maximum temperature deviation within a set number of consecutive acquisition cycles is less than or equal to zero. Then, it is determined that the rate of change of the maximum temperature deviation is in a convergent state.

[0036] Conversely, if the rate of change is negative or zero, it indicates that local thermal compensation has effectively suppressed the expansion of temperature deviation. In this case, the current heating rate and local thermal compensation power should be maintained and monitored. Considering that while reducing the heating rate to suppress temperature field divergence eliminates the tendency for deviation to expand, an excessively slow heating rate will prolong the overall curing cycle and reduce production efficiency. Furthermore, when the temperature deviation converges to a very small range, the heat conduction in each region of the component has reached dynamic equilibrium again, possessing the physical conditions to restore efficient heating.

[0037] Therefore, after determining that the rate of change of the maximum temperature deviation is in a convergent state, a rate recovery step is further executed: when the maximum temperature deviation is less than the preset allowable threshold, the heating rate is gradually increased according to the preset gradient. The gradient is calibrated through previous trial molding tests to avoid the temperature deviation from diverging again due to excessively rapid recovery heating, until the curing heating stage ends and the heat preservation curing stage begins. The preset allowable threshold is obtained by taking the smaller value between the maximum allowable temperature difference specified in the curing process specification of the carbon fiber prepreg and the critical temperature difference in the thermal conduction simulation of the thickness abrupt change zone of the track control console, and multiplying it by a safety factor of 0.85 to 0.95. S3. Based on the temperature of each thermocouple and the resin curing kinetic model, the real-time viscosity curve is calculated. When the curve drops to a local minimum point and the rate of change of the maximum temperature deviation converges, a pressurization operation is executed.

[0038] In autoclave molding, the timing of pressurization is crucial to determining the final quality of the component. Pressurizing too early results in excessively low resin viscosity, leading to excessive resin extrusion and uneven fiber distribution in the component. Pressurizing too late results in excessively high resin viscosity or the resin already beginning to gel, failing to effectively compact interlayer air bubbles and voids, leading to excessive porosity. Resin viscosity typically exhibits a curve that first decreases and then increases with temperature. Its local minimum corresponds to the lowest viscosity window during which resin flow is optimal, before gel cross-linking occurs.

[0039] Meanwhile, pressurization must be carried out under relatively uniform temperature conditions; otherwise, inconsistent viscosity states in local areas will prevent uniform compaction even with pressure. Therefore, this step combines real-time viscosity state calculated based on the curing kinetics model with real-time temperature field uniformity criteria to jointly determine the triggering of the pressurization command.

[0040] Please see Figure 2 As shown, step S3 specifically includes the following: S201, the arithmetic average of the thermocouple temperatures collected in real time during the curing and heating stage is obtained; taking the collection period as the time step, the real-time average at the current moment is substituted into the differential equation of the resin curing kinetic model, and the resin curing degree at the current moment is calculated step by step using the numerical integration iteration method; the resin curing degree and the real-time average are substituted into the viscosity conversion equation to calculate the real-time viscosity, and a real-time viscosity curve is generated according to the time series.

[0041] The differential equation of the resin curing kinetics model is as follows: .

[0042] The viscosity conversion equation is: .

[0043] In the formula, The absolute temperature is the real-time average value. For time, This refers to the degree of resin curing. This is the real-time viscosity. These are the kinetic constants pre-calibrated using differential scanning calorimetry. All of these are material constants that were pre-calibrated through tests using a pure resin rheometer.

[0044] S202. After performing median filtering on the real-time viscosity curve to eliminate noise interference, a sliding window method is used to detect local minima. The window width is set to an odd number of sampling points. The viscosity values ​​of the center point and the adjacent points are compared. If the viscosity of the center point is less than or equal to that of the points on both sides, then the point is determined to be a local minima.

[0045] At the same time, the maximum temperature deviation change rate of the current acquisition cycle is extracted, and it is determined whether the maximum temperature deviation change rate has entered a convergence state that is less than or equal to zero.

[0046] Furthermore, the local minimum point is a valid local minimum point that, after median filtering, exhibits a downward trend followed by an upward trend within a preset sliding window; isolated peaks, single-cycle fluctuations, or points that do not form a continuous downward trend followed by an upward trend are not considered as pressurization trigger points. A pressurization operation command is only sent when this valid local minimum point is detected and the maximum temperature deviation change rate is in a convergent state.

[0047] S203. When the local minimum point is detected and the rate of change of the maximum temperature deviation is in a convergent state, it indicates that the crosslinking reaction of the resin has not yet entered the rapid gelation stage and still has flow and wettability. At this time, the temperature field of each region of the component has become stable and uniform. Pressurization at this time can maximize the discharge of interlayer bubbles and compact the fibers without causing internal defects due to local temperature differences. Then, a pressurization operation instruction is sent to the autoclave.

[0048] Furthermore, after the autoclave receives the pressurization command and executes the pressurization operation to reach the target molding pressure, the pressurization system of the autoclave is controlled to maintain a constant pressure inside the autoclave, and the heating program is continued to be controlled to raise the component temperature to the highest heat preservation temperature required for complete resin curing. At this highest heat preservation temperature, a preset heat preservation and curing time, such as 90 minutes, is maintained to promote the resin to complete a full cross-linking reaction. After the heat preservation and curing process is completed, the cooling is started according to the set cooling program, and then the heat preservation, curing and cooling stages begin.

[0049] S4. During the heat preservation, curing and cooling stages, calculate the average absolute value of the temperature difference between each thermocouple and the average temperature as the temperature field uniformity deviation, and dynamically adjust the flow rate of the heating or cooling medium in each independent temperature control circuit with the goal of minimizing this deviation.

[0050] During the curing stage, the resin undergoes a cross-linking reaction, releasing a significant amount of heat, especially in resin-rich areas such as regions with abrupt changes in thickness. This concentrated heat release can easily lead to localized overheating and thermal stress concentration, potentially causing component deformation or cracking. During the cooling stage, the edges and thin-walled areas cool rapidly, while thick-walled areas cool slowly; this uneven cooling rate also introduces residual stress. Therefore, maintaining a high level of temperature field uniformity throughout the entire process is crucial. However, traditional isostatic control strategies cannot address the spatially uneven heat release and dissipation. Therefore, this step employs an independent flow rate regulation strategy based on real-time feedback of the spatial temperature distribution.

[0051] In one specific embodiment, after entering the heat preservation, curing and cooling stage, the temperature of each thermocouple is continuously collected.

[0052] First, during the heat preservation and curing stage, the arithmetic mean of all thermocouple temperatures is calculated as the average temperature. The sum of the absolute values ​​of the differences between each thermocouple temperature and the average temperature is divided by the total number of thermocouples to obtain the temperature field uniformity deviation. This deviation reflects the degree of dispersion of the entire temperature field.

[0053] Subsequently, the thermocouple temperature in the corresponding mold area of ​​each independent temperature control loop is compared with the average temperature. If the thermocouple temperature is higher than the average temperature, it indicates that there is uneven heat conduction, concentrated cross-linking heat release of resin, or excessive heat supply from the independent loop, resulting in temperature overshoot. In this case, the local temperature deviation in the area is determined to be positive. If the thermocouple temperature is lower than the average temperature, it indicates that the local heat dissipation in the area is too fast, heat conduction is blocked, or the independent loop is insufficient. In this case, the local temperature deviation in the area is determined to be negative. If the thermocouple temperature is equal to the average temperature or the difference is within a very small dead zone, it indicates that the temperature in the area is synchronized with the overall temperature field. In this case, the local temperature deviation is determined to be zero, and the current medium flow rate of the independent temperature control loop in the area is kept constant.

[0054] For areas with positive local temperature deviations, the flow rate of the heating medium is reduced proportionally based on the magnitude of the positive deviation, or the flow rate of the cooling medium is increased proportionally to remove the latent heat released by the resin crosslinking reaction. For areas with negative local temperature deviations, the flow rate of the heating medium is increased proportionally based on the magnitude of the negative deviation, or the flow rate of the cooling medium is decreased proportionally. Specifically, the proportionality based on the magnitude of the positive or negative deviation is achieved by dividing the value of the positive or negative deviation by the reference temperature difference, and directly converting it into the percentage change in the opening of the corresponding medium-controlled valve. The reference temperature difference is the maximum allowable temperature fluctuation range determined through preliminary mold testing, with a value of 5℃ to 10℃.

[0055] When the heat preservation and curing process is completed and cooling is initiated according to the cooling program, the flow rate adjustment automatically switches to the cooling stage: based on the temperature deviation of each area from the average temperature, the flow rate of the cooling medium in the corresponding independent temperature control loop is dynamically adjusted proportionally. Specifically, for areas where the temperature is higher than the average temperature (i.e., the local temperature deviation is positive), the flow rate of the cooling medium is increased proportionally to the positive deviation to accelerate local cooling; for areas where the temperature is lower than the average temperature (i.e., the local temperature deviation is negative), the flow rate of the cooling medium is decreased proportionally to the negative deviation to slow down the local cooling rate, thereby avoiding internal stress caused by inconsistent thermal contraction rates.

[0056] It should be noted that the proportional gain coefficient used in the cooling stage is independent of that used in the heat preservation and curing stage, and needs to be calibrated separately through a step response test of the cooling circuit. The values ​​of the two can be the same or different, and the actual test results shall prevail.

[0057] Furthermore, considering that the exothermic crosslinking of the resin during the heat preservation and curing stage has nonlinear characteristics, and that there is a pure hysteresis effect between the adjustment of the medium flow rate and the internal heat conduction of the component, a single proportional adjustment based solely on the current deviation amplitude may result in insufficient response or cause the deviation to oscillate between positive and negative polarities. Therefore, the changing trend of the temperature field uniformity deviation is continuously monitored to perform adaptive closed-loop correction.

[0058] If the temperature field uniformity deviation of the current acquisition cycle is less than or equal to the temperature field uniformity deviation of the previous acquisition cycle, it indicates that the aforementioned proportional flow rate adjustment direction is correct and the intensity is appropriate, and the global temperature field is converging towards uniformity. Therefore, the current adjustment direction of the heating or cooling medium flow rate of each independent temperature control loop should be maintained.

[0059] If the temperature field uniformity deviation in the current acquisition cycle is greater than that in the previous acquisition cycle, it indicates that the current adjustment is insufficient to overcome local heat release disturbances or thermal inertia, and the temperature field non-uniformity is intensifying. Therefore, based on the current proportional calculation results, the adjustment range of the heating or cooling medium flow rate of each independent temperature control loop is further increased. For example, an additional fixed valve opening step is superimposed to enhance the suppression effect, forcing the temperature field uniformity deviation to re-enter the downward channel.

[0060] S5. When the overall temperature change rate approaches zero and the highest temperature is lower than the glass transition temperature of the current material, perform the demolding operation.

[0061] At the end of the cooling phase, if a significant temperature gradient still exists within the component or the temperature exceeds the material's glass transition temperature, resulting in a lower modulus, forced demolding will cause irreversible thermal deformation under the component's own weight or demolding force. If the overall temperature is still changing rapidly, it indicates that the component has not yet reached a stable thermal equilibrium state, and its dimensions will continue to change after demolding, affecting assembly accuracy. Therefore, this step establishes a dual-condition demolding criterion based on the dynamic correlation between the overall temperature change trend and the material's glass transition temperature to ensure that the component is demolded under conditions of stable mechanical properties and minimal thermal stress.

[0062] Please see Figure 3 As shown, step S5 specifically includes the following: S301. During the cooling phase, the average temperature is calculated based on the temperatures of all thermocouples. The average temperature of the current acquisition cycle is subtracted from the average temperature of the previous acquisition cycle and then divided by the acquisition cycle time interval using a differential algorithm. The derivative of the average temperature with respect to time is calculated as the overall temperature change rate. At the same time, the real-time temperature data of all thermocouples are compared and the maximum value is extracted as the highest temperature.

[0063] S302. When the overall temperature change rate approaches zero (i.e., the absolute value of the change rate is less than or equal to 0.5℃ / min), and the highest temperature is lower than the current glass transition temperature of the material, it indicates that the component has basically reached a state of thermal equilibrium, and the material modulus has increased to a level that can withstand the demolding load without significant deformation. At this point, the vacuum bag seal is released and the pressure in the autoclave is released. Subsequently, the carbon fiber composite component of the track controller is separated from the mold, and the demolding operation is performed. This results in a finished track controller component with stable dimensions, low internal stress, and no warping deformation.

[0064] The method for obtaining the glass transition temperature of the current material is as follows: the real-time average value of the temperature collected by all thermocouples from the start of the curing and heating stage to the current moment is multiplied and accumulated in combination with the collection period time, and the cumulative thermal history value up to the current moment is calculated by numerical integration.

[0065] The calculated cumulative heat history value is substituted into the resin curing kinetic model, and the kinetic differential equation is solved by numerical integration to calculate the degree of resin curing at the current moment.

[0066] The calculated degree of resin curing is substituted into a preset correlation equation between glass transition temperature and degree of curing to calculate the current glass transition temperature of the material, which dynamically changes with the degree of resin crosslinking. The correlation equation adopts the DiBenedetto equation form: .

[0067] in, This is the glass transition temperature at the current degree of cure. For the degree of curing and , The glass transition temperature of the uncured resin. The glass transition temperature of the fully cured resin. This is a material constant related to the free volume change of the resin system, with a value ranging from 0.5 to 2.0.

[0068] This indicates the increase in glass transition temperature caused by curing. This represents the linear superposition of the initial transition temperature and the enhancement effect; The equation represents the nonlinear normalization constraint factor; it also represents the glass transition temperature of the resin at the current degree of cure, thus realizing the transition from... arrive Nonlinear smooth transition.

[0069] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0070] Those skilled in the art will recognize that the algorithmic steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0071] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0072] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0073] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for molding a carbon fiber composite autoclave for a track control console, characterized in that, include: S1. Lay carbon fiber prepreg in the mold, set elastic pressure compensation pads in the thickness abrupt area, embed thermocouples, cover with vacuum bag, seal and vacuum, and then place in a thermostatic tank. S2. During the curing and heating stage, the temperature of each thermocouple is collected synchronously according to the set collection cycle. The average temperature of all thermocouples is calculated based on the temperature. The absolute value of the difference between each thermocouple temperature and the average temperature is calculated, and the largest absolute value is taken as the maximum temperature deviation. Using the average temperature as the reference temperature, the deviation of each thermocouple temperature relative to the reference temperature is calculated. When any deviation is negative and the maximum temperature deviation value within a continuously set number of acquisition cycles is monotonically increasing, the mold area number corresponding to the thermocouple with the negative deviation is retrieved, and the output power of the independent temperature control circuit corresponding to that number is increased for local thermal compensation. After performing local thermal compensation, the rate of change of the maximum temperature deviation is calculated. If the rate of change is positive, the heating rate of the autoclave is reduced by a preset step size until the rate of change of the maximum temperature deviation is less than or equal to zero within a set number of consecutive acquisition cycles. Then, the rate of change of the maximum temperature deviation is determined to be in a convergent state. After determining that the rate of change of the maximum temperature deviation is in a convergent state, the method further includes: when the maximum temperature deviation is less than a preset allowable threshold, gradually increasing the heating rate according to a preset gradient until the curing heating stage ends and entering the heat preservation curing stage. S3. Input the thermocouple temperatures of each stage of the curing and heating process into the resin curing kinetics model to dynamically calculate and generate real-time viscosity curves. Continuously monitor the local minimum points of the real-time viscosity curve; at the same time, extract the rate of change of the maximum temperature deviation and determine whether the rate of change of the maximum temperature deviation has entered the convergence state. When both the local minimum point is detected and the rate of change of the maximum temperature deviation is in a convergent state, a command to pressurize the autoclave is sent to the autoclave. S4. During the heat preservation, curing and cooling stages, calculate the mean value of the absolute value of the temperature difference between each thermocouple and the average temperature as the temperature field uniformity deviation, and dynamically adjust the flow rate of the heating or cooling medium of each independent temperature control circuit with the goal of minimizing this deviation. S5. When the overall temperature change rate approaches zero and the highest temperature is lower than the glass transition temperature of the current material, perform the demolding operation.

2. The method for molding a track control console using a carbon fiber composite autoclave as described in claim 1, characterized in that, S1 specifically includes: Carbon fiber prepreg is laid layer by layer on the surface of the mold cavity according to the preset layup sequence; An elastic pressure compensation pad is laid in the thickness abrupt area of ​​the track control console, and the elastic pressure compensation pad is in contact with the carbon fiber prepreg. The thermocouple is embedded in the characteristic interlayer location of the carbon fiber prepreg, which includes a thickness abrupt region, a corner region, and a planar center region. The laid carbon fiber prepreg and elastic pressure compensation pad are covered with a vacuum bag film and the edges are sealed. A vacuum is then drawn to form a vacuum chamber. The encapsulation assembly, which includes a mold, carbon fiber prepreg, elastic pressure compensation pad, thermocouple, release cloth, breathable felt and vacuum bag film, is placed into an autoclave, which is equipped with multiple independent temperature control circuits.

3. The method for molding a track control console using a carbon fiber composite autoclave as described in claim 1, characterized in that, The thickness abrupt change area includes: the junction area between the work surface and the side wall, the groove or boss area on the work surface for installing control elements, and the reinforcing rib area at the bottom of the work surface.

4. The method for molding a track control console using a carbon fiber composite autoclave as described in claim 1, characterized in that, S4 specifically includes: After entering the heat preservation, curing and cooling stage, the temperature of each thermocouple is continuously collected; The arithmetic mean of all thermocouple temperatures is calculated as the average temperature. The sum of the absolute values ​​of the differences between each thermocouple temperature and the average temperature is divided by the total number of thermocouples to obtain the temperature field uniformity deviation. The thermocouple temperature in the corresponding mold area of ​​each independent temperature control loop is compared with the average temperature. If the thermocouple temperature is higher than the average temperature, the local temperature deviation in that area is determined to be positive; if the thermocouple temperature is lower than the average temperature, the local temperature deviation in that area is determined to be negative. For areas with positive local temperature deviations, the flow rate of the heating medium is reduced proportionally or the flow rate of the cooling medium is increased proportionally based on the magnitude of the positive deviation; for areas with negative local temperature deviations, the flow rate of the heating medium is increased proportionally or the flow rate of the cooling medium is decreased proportionally based on the magnitude of the negative deviation. After entering the cooling stage, the flow rate of the cooling medium in the corresponding independent temperature control loop is dynamically adjusted proportionally according to the deviation between the temperature of each area and the average temperature.

5. The method for molding a track control console using a carbon fiber composite autoclave as described in claim 4, characterized in that, The S4 further includes: Continuously monitor the temperature field uniformity deviation; if the temperature field uniformity deviation of the current acquisition cycle is less than or equal to the temperature field uniformity deviation of the previous acquisition cycle, maintain the current adjustment direction of the heating or cooling medium flow rate of each independent temperature control loop. If the temperature field uniformity deviation in the current acquisition cycle is greater than that in the previous acquisition cycle, the adjustment range of the heating or cooling medium flow rate of each independent temperature control loop will be increased.

6. The method for molding a track control console using a carbon fiber composite autoclave as described in claim 1, characterized in that, S5 specifically includes: During the cooling phase, the derivative of the average temperature with respect to time is calculated based on the temperatures of all thermocouples, which is used as the overall rate of temperature change, and the highest temperature among all thermocouples is obtained. When the overall temperature change rate approaches zero and the highest temperature is lower than the glass transition temperature of the current material, the vacuum bag seal is released and the autoclave pressure is released. Then, the carbon fiber composite component of the track control console is separated from the mold, and the demolding operation is performed.

7. The method for molding carbon fiber composite material in an autoclave for a track controller as described in claim 6, characterized in that, The method for obtaining the glass transition temperature of the current material is as follows: The real-time average temperature of all thermocouples collected from the solidification and heating stage up to the present moment is multiplied and accumulated by combining the collection period time, and the cumulative thermal history value up to the present is calculated by numerical integration. Substitute the cumulative heat history value into the resin curing kinetic model to calculate the degree of resin curing; Substitute the degree of resin curing into the preset glass transition temperature and degree of curing correlation equation to calculate the current glass transition temperature of the material.

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