High-efficiency forming process of glass fiber reinforced plastic composite material

Abstract

The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of a glass steel composite material, and relates to the technical field of composite material forming manufacturing. The application provides a high-efficiency forming process of

Description

Technical Field

[0001] This invention relates to the field of composite material molding and manufacturing technology, specifically to an efficient molding process for fiberglass composite materials. Background Technology

[0002] Fiberglass reinforced plastic (FRP) is widely used in transportation, construction, corrosion protection, and general industrial components due to its advantages such as high specific strength, corrosion resistance, and strong design flexibility. Existing molding processes for FRP composites mainly include hand lay-up molding, spray molding, vacuum bagging, vacuum infusion, resin transfer molding, compression molding, pultrusion molding, filament winding, and prepreg hot pressing and autoclaving, covering different manufacturing needs from small-batch to large-scale production, and from simple shapes to complex structures. Among these, resin transfer molding (RTM) has become one of the important molding methods for high-performance composite components due to its advantages such as high dimensional accuracy, smooth double-sided finish, ability to mold complex structures, and suitability for medium-batch production. The key technical aspects of existing RTM processes mainly include resin flow and filling control within the mold cavity, injection pressure control, and curing process control. Especially in the molding of thick-walled or large complex structural parts, it is usually necessary to design the filling process and the curing process in thick-walled areas in conjunction with the structural characteristics of the component.

[0003] However, the existing technologies mentioned above still have shortcomings in practical applications: vacuum injection is prone to problems such as long flow paths, narrow injection windows, uneven filling and local missing glue in thick-walled or large complex parts, and the curing cycle is relatively long. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an efficient molding process for fiberglass composite materials. The technical problem this invention aims to solve is: how to implement dynamic adjustment of zones during the injection process using a multi-zone vacuum injection method and coordinate with in-mold curing to solve the problems of long flow paths, uneven filling, localized glue shortages, and long curing cycles in the molding of thick-walled or large complex parts.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency molding process for fiberglass composite materials, comprising: S1. A preform is formed by laying up glass fiber reinforced material, which is then placed in the lower mold cavity of the mold. After the mold is closed, a closed mold cavity is formed, and a sealing structure is provided to ensure the airtightness of the mold cavity under injection pressure. S2. Based on the three-dimensional structural model or engineering drawing of the product, and combined with process simulation analysis, the resin flow front is simulated in advance to determine the potential flow resistance area. The flow resistance area includes the thick-walled area and the geometrically complex area. According to the flow resistance area, at least two independent injection zones are divided in the mold cavity. A corresponding resin injection port and vent are set for each injection zone. Each injection zone is independently connected to the RTM injection machine and the vacuum suction unit through a valve group composed of proportional adjustment valves. A bypass connection channel controlled by the zone valve is set between adjacent injection zones. S3. After evacuating each injection zone to the target vacuum level and completing pressure holding and leak detection, the RTM injection machine is started to inject the resin system into each injection zone. During the injection process, a dual control mode of injection pressure and flow rate is adopted: the pressure detection signal and the resin front arrival signal of each injection zone are collected. The imbalance criterion is that the pressure difference between any two injection zones is greater than the first threshold or the time difference of the resin front arrival signal is greater than the second threshold. When the imbalance criterion is triggered, the valve group is controlled to perform PID adjustment on the injection path of each injection zone, and the bypass connection channel is selectively opened or closed, so that each injection zone meets the requirement that the pressure difference does not exceed the first threshold or the time difference does not exceed the second threshold during the injection until the full cavity is filled. This shortens the effective flow path and suppresses local missing glue while avoiding fiber erosion. S4. After filling the entire cavity, close the injection port and maintain pressure. Once the cavity pressure stabilizes, start the mold heating unit to cure the resin system in-mold according to the preset temperature rise curve. During the curing process, monitor the internal temperature of the thick-walled area in real time to ensure that the exothermic peak does not exceed the allowable temperature of the resin system until the demolding strength is reached. Then, open the mold and demold to obtain the fiberglass composite material product.

[0006] Preferably, the thick-walled region is a region in the three-dimensional structural model or engineering drawing of the product where the local wall thickness is greater than or equal to a preset thick-walled threshold, and the geometrically complex region is a region in the three-dimensional structural model or engineering drawing of the product that satisfies any of the following structural features: dense ribs, abrupt changes in cross-section, narrow flow channels, deep concave cavities, sharply turning flow channels, or semi-closed cavities formed by local enclosure.

[0007] Preferably, the division of the injection zones satisfies the following principles: the thick-walled area or the geometrically complex area is treated as a separate injection zone, or the thick-walled area or the geometrically complex area is divided into different injection zones, and the shortest resin flow path length from the corresponding resin injection port to any position to be filled in the corresponding injection zone is not greater than a preset maximum flow path threshold, which is determined by process simulation analysis.

[0008] Preferably, the resin injection port of the injection zone is located on the priority filling side of the corresponding injection zone, and the vent is located on the end venting side opposite to the resin injection port. Furthermore, the flow guiding medium is optimized and laid in the mold cavity according to the simulation results. The flow guiding medium is laid along the preset main flow direction and covers at least one resin front edge reaching the signal acquisition position.

[0009] Preferably, the target vacuum degree is a gauge pressure negative pressure state and not lower than -0.08MPa. The pressure holding and leak detection includes: after reaching the target vacuum degree, shutting down the vacuum suction unit, and determining that the pressure holding and leak detection is completed when the mold cavity pressure rise value does not exceed the preset allowable rise value within the preset leak detection time.

[0010] Preferably, the pressure detection signal inside the mold cavity is collected by pressure sensors respectively installed on the mold cavity wall of each injection zone; the resin front arrival signal is collected by a front-edge sensor installed at a predetermined monitoring position in each injection zone, wherein the front-edge sensor is any one of an electrode conduction sensor, an optical fiber sensor, or a dielectric response sensor.

[0011] Preferably, the PID control includes: opening the bypass connection channel to perform inter-zone pressure equalization, and closing the bypass connection channel when the pressure difference does not exceed a first threshold and the time difference does not exceed a second threshold.

[0012] Preferably, the resin system is a curable resin composition used to impregnate the preform and can be cured in the mold to form a resin matrix. The resin system includes a matrix resin and a curing component. Before performing step S3, the resin system is degassed and the injection temperature of the resin system is controlled within a preset temperature range so that the viscosity of the resin system during injection does not exceed a preset upper limit of viscosity.

[0013] Preferably, the preset heating curve includes a heating stage and a holding stage: heating to a preset curing temperature and holding for a preset holding time; the demolding strength is determined by any of the following demolding criteria: the dielectric curing degree in the mold reaches the preset curing degree criterion, the temperature-time integral inside the thick-walled region reaches the preset curing completion criterion and the exothermic peak has passed, and the surface hardness of the product reaches the preset hardness criterion.

[0014] This invention provides a highly efficient molding process for fiberglass composite materials. It offers the following advantages: This efficient molding process for fiberglass composite materials effectively shortens the resin flow path within the mold cavity and reduces filling resistance by pre-identifying thick-walled and geometrically complex areas of the product and dividing them into multiple independent injection zones using process simulation. During injection, real-time monitoring is implemented based on the mold cavity pressure difference and the resin front arrival time difference.

[0015] A PID algorithm is used to dynamically adjust the proportional valve group and selectively open bypass channels between zones to achieve balanced mold filling in each zone, avoiding localized defects such as insufficient glue and dry spots, and suppressing fiber erosion displacement that may be caused by high-pressure injection. During the curing stage, the exothermic peak is controlled by real-time monitoring of the internal temperature of the thick-walled zone, optimizing the curing process and preventing overheating damage. This invention improves the molding quality and efficiency of complex fiberglass products and is suitable for the mass production of high-performance composite material components. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a flowchart of the signal acquisition and control process of the present invention; Figure 3 This is a flowchart of the curing and demolding control process of the present 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] Example 1 like Figure 1-3 As shown, this embodiment of the invention provides an efficient molding process for fiberglass composite materials, including: S1. A preform is formed by laying up glass fiber reinforced material and placing it in the lower mold cavity of the mold. After the mold is closed, a closed mold cavity is formed, and a sealing structure is set to ensure the airtightness of the mold cavity under injection pressure.

[0019] S2. Based on the 3D structural model or engineering drawing of the product, and combined with process simulation analysis, simulate the resin flow front to determine potential flow resistance areas. These areas include thick-walled regions and geometrically complex regions. Divide the mold cavity into at least two independent injection zones according to the flow resistance areas. Set corresponding resin injection ports and vents for each injection zone. Use a valve group composed of proportional control valves to independently connect each injection zone to the RTM injection molding machine and vacuum suction unit. Set a bypass connection channel between adjacent injection zones, controlled by zone valves. Thick-walled regions are areas in the 3D structural model or engineering drawing of the product where the local wall thickness is greater than or equal to a preset thick-walled threshold. Geometrically complex regions are areas in the 3D structural model or engineering drawing of the product that satisfy any of the following structural characteristics: dense ribs, abrupt changes in cross-section, narrow flow channels, deep cavities, sharp bends in the flow channel, or semi-enclosed cavities formed by partial enclosure. The division of injection zones follows these principles: thick-walled or geometrically complex areas are treated as separate injection zones, or they are divided into different injection zones. Furthermore, the shortest resin flow path length from the corresponding resin injection port to any filling position within each injection zone does not exceed a preset maximum flow path threshold, which is determined through process simulation analysis. The resin injection port of each injection zone is located on the priority filling side, and the vent is located on the end venting side opposite to the resin injection port. The flow guiding medium is optimized and laid within the mold cavity based on simulation results. This medium is laid along a preset main flow direction and covers at least one resin leading edge reaching the signal acquisition position.

[0020] S3. After evacuating each injection zone to the target vacuum level and completing the pressure holding and leak detection, start the RTM injection molding machine to inject the resin system into each injection zone. During the injection process, a dual control mode of injection pressure and flow rate is adopted: the pressure detection signal and the resin front arrival signal of each injection zone are collected. The imbalance criterion is that the pressure difference between any two injection zones is greater than the first threshold or the time difference of the resin front arrival signal is greater than the second threshold. When the imbalance criterion is triggered, the control valve group performs PID adjustment on the injection path of each injection zone and selectively opens or closes the bypass connection channel, so that the pressure difference between each injection zone does not exceed the first threshold or the time difference does not exceed the second threshold during the injection until the entire cavity is filled. This shortens the effective flow path and suppresses local missing glue while avoiding fiber erosion. The target vacuum level is a gauge pressure negative pressure state and not lower than -0.08MPa. The pressure holding and leak detection includes: after reaching the target vacuum level, shutting off the vacuum suction unit, and determining that the pressure recovery value of the mold cavity does not exceed the preset allowable recovery value within the preset leak detection time, thus confirming that the pressure holding and leak detection is completed. The pressure detection signal within the mold cavity is acquired by pressure sensors respectively installed on the mold cavity walls of each injection zone. The resin leading edge arrival signal is acquired by a leading edge sensor installed at a predetermined monitoring position within each injection zone. The leading edge sensor can be any one of an electrode conduction sensor, an optical fiber sensor, or a dielectric response sensor. PID control includes: opening a bypass connection channel to perform inter-zone pressure equalization, and closing the bypass connection channel when the pressure difference does not exceed a first threshold and the time difference does not exceed a second threshold. The resin system is a curable resin composition used for impregnating a preform and curing in the mold to form a resin matrix. The resin system includes a matrix resin and a curing component. Before performing step S3, the resin system is degassed, and the injection temperature of the resin system is controlled within a preset temperature range so that the viscosity of the resin system during injection does not exceed a preset upper limit of viscosity.

[0021] S4. After filling the entire cavity, close the injection port and maintain pressure. Once the cavity pressure stabilizes, start the mold heating unit to cure the resin system in-mold according to the preset temperature rise curve. During the curing process, monitor the internal temperature of the thick-walled region in real time to ensure that the exothermic peak does not exceed the allowable temperature of the resin system, until the demolding strength is reached. Then, open the mold and demold to obtain the fiberglass composite product. The preset temperature rise curve includes a heating stage and a holding stage: heating to the preset curing temperature and holding for the preset holding time. The demolding strength is determined by any of the following demolding criteria: the in-mold dielectric curing degree reaches the preset curing degree criterion, the internal temperature-time integral of the thick-walled region reaches the preset curing completion criterion and the exothermic peak has passed, or the surface hardness of the product reaches the preset hardness criterion.

[0022] This invention manages injection in sections for thick-walled and geometrically complex areas, dynamically adjusting the process based on mold cavity pressure and resin front arrival information during resin introduction. This ensures relatively balanced resin filling within each injection section, effectively shortening the equivalent resin flow path and suppressing molding defects such as localized missing resin, dry spots, and porosity. Simultaneously, by controlling injection pressure and flow rate during injection, it reduces erosion and disturbance to the fiber reinforcement, helping to maintain fiber structural integrity. This improves the filling adequacy, molding uniformity, and process stability of complex fiberglass composite products, facilitating efficient and stable production while maintaining consistent product quality.

[0023] Example 2 This embodiment illustrates how to achieve path controllability in the resin introduction process by setting independent introduction zones for thick-walled and geometrically complex areas in the product and limiting the resin flow path length within a single introduction zone.

[0024] 1. Preparation of preforms and molds This embodiment of the fiberglass load-bearing structural component is used for equipment load-bearing purposes. The length of a single finished piece is 1800mm, and the maximum width is 620mm. The nominal wall thickness of the main body area of ​​the product is 3.5-6mm, with local thickening structures formed in the middle reinforcement area and the flange areas at both ends, where the maximum designed wall thickness is 14mm.

[0025] The preform is prepared by a combination of E-glass fiber fabric and chopped strand mat, with the fabric having a basis weight of 600 g / m² and the chopped strand mat having a basis weight of 450 g / m².

[0026] Based on the product structure, the number of lay-up layers is increased in the central reinforcement area and flange area, so that the lay-up thickness in the central reinforcement area and flange area corresponds to a wall thickness of 10-14mm after molding. The correspondence is determined based on molding experience under the same process conditions. The lay-up thickness in other areas corresponds to a wall thickness of 3.5-6mm after molding.

[0027] The preform with the completed layup is placed in the cavity of a metal mold. The size of the mold cavity is consistent with the shape of the product. A vacuum-sealed space is formed around the perimeter by sealing strips and vacuum bags.

[0028] 2. Determination of Thick-walled Regions and Geometrically Complex Regions Prior to this molding process, the wall thickness distribution and structural characteristics were confirmed based on the three-dimensional structural model of the product. Areas with a local wall thickness greater than or equal to 10 mm were defined as thick-walled areas, including the central reinforcement mounting area and the flange areas at both ends.

[0029] Meanwhile, according to the structural annotations in the engineering drawings and the mold structure, there is a rib structure on one side of the product. The height of the rib is marked as 22-28mm, and the center distance between adjacent ribs is 18-25mm. There is a narrow and long groove cavity on the other side of the product. The groove length is about 260mm, and the minimum effective flow width is 8mm. The above-mentioned rib area and groove area are identified as geometrically complex areas.

[0030] 3. Import partitioning and interface layout Based on the location distribution of the thick-walled area and the geometrically complex area within the cavity, the import space is divided into three independent import partitions, which are numbered as import partition A, import partition B and import partition C, respectively.

[0031] Among them, import zone A covers the central reinforcement installation area of ​​the product, import zone B covers the end flange area of ​​the product, and import zone C covers the dense rib area and narrow groove cavity.

[0032] The path length threshold was determined based on stable introduction experience under the process conditions used in this molding process, setting the maximum allowable resin flow path length within a single introduction zone to 420 mm. When the flow path length within a single introduction zone exceeds the threshold, a decrease in resin propulsion speed is likely to occur under the same process conditions.

[0033] Based on cavity size measurement and layup location confirmation, the furthest flow path length in import zone A is 360mm, in import zone B it is 390mm, and in import zone C it is 410mm, all of which do not exceed the set threshold.

[0034] 4. Setting of glue inlet, vent, and guide medium Each import zone is equipped with a separate resin inlet and vacuum outlet. The resin inlet for importing zone A is located in a straight area on one side of the central reinforcement zone, and the vent is located on its opposite edge.

[0035] The resin inlet for zone B is located at the outer edge of the flange area, and the vent is located at the inner edge of the flange area.

[0036] The resin inlet for importing partition C is located on the starting side of the rib arrangement, and the vent is located at the end of the rib and near the far end of the groove cavity.

[0037] A flow guiding medium is laid between each resin inlet and the preform. The flow guiding medium is a mesh-like flow guiding cloth with a surface density of 180 g / m², laid along a preset main flow direction, which is the direction of the line connecting the resin inlet to the corresponding vent. Within each inlet section, the flow guiding medium covers a resin front monitoring position, with the monitoring position located 220 mm from the actual measurement distance of the corresponding resin inlet.

[0038] 5. Bypass connection channel setting status A first bypass connection channel is set between import partition A and import partition C, and a second bypass connection channel is set between import partition B and import partition C. Both bypass connection channels are controlled by manual ball valves.

[0039] After completing the division of the import zones, setting the resin inlet and vacuum outlet of each import zone, laying the guiding medium, and arranging the bypass connecting channels, check and confirm that all ball valves corresponding to the bypass connecting channels are in the closed state, so that each import zone remains independent of each other before resin import.

[0040] Through the above steps, the injection zones are divided before resin introduction, and resin inlets, vacuum vents, and flow guiding media are set in each injection zone to ensure that thick-walled areas and geometrically complex areas maintain independent filling states during the initial resin introduction process. During actual molding, the resin continuously advances along the preset flow path in each injection zone without stagnation, localized resin shortages, or fiber insufficiency caused by excessively long flow paths. After molding, the product undergoes visual inspection and partial cross-section verification. The internal structure of the thick-walled, ribbed, and grooved areas remains intact, with no significant dry spots or void defects observed. Under the conditions of this embodiment, continuous filling of complex structural areas was achieved.

[0041] Example 3 This embodiment relates to a resin introduction method implemented during the molding process of fiberglass composite material products containing thick-walled regions and densely ribbed regions, wherein the resin introduction process is dynamically adjusted based on the pressure difference of the introduction zone and the time difference of the resin front arrival.

[0042] 1. Product and Trial Production Conditions The product manufactured in this trial is an integrated fiberglass reinforced structural component. The engineering drawings show that the product's external dimensions are approximately 1200mm × 800mm × 60mm.

[0043] The central area of ​​the product has a thick-walled structure formed by superimposed reinforcing ribs. After the layup is completed, the corresponding position of the preform is measured with a vernier caliper. The maximum wall thickness is measured to be 18.2 mm. The wall thickness of this area is higher than that of other areas of the product, and it is treated as a thick-walled area.

[0044] Multiple crisscrossing ribs are set on both sides of the product, with the minimum spacing between the ribs being about 22mm, forming narrow flow channels and semi-closed cavity structures in some areas.

[0045] The mold is a closed steel mold, and the mold cavity is sealed using a combination of silicone rubber sealing strips and vacuum bags. The glass fiber reinforcement material is a multi-layered biaxial glass fiber fabric, which forms an integral preform after the layers are laid up.

[0046] 2. Import partition settings Based on the product engineering drawings and the actual layup, three independent entry zones are divided within the mold cavity, denoted as entry zone A, entry zone B, and entry zone C, respectively. Import partition A corresponds to the thick-walled area in the center of the product, while import partitions B and C correspond to the densely ribbed areas on both sides, respectively.

[0047] Each inlet section is equipped with a resin inlet and a vacuum exhaust port. Adjacent inlet sections are connected by a bypass pipe controlled by a ball valve, with an inner diameter of 10mm.

[0048] 3. Vacuuming and pressure testing for leaks. After sealing, the same rotary vane vacuum pump was used to sequentially evacuate the three inlet sections. After approximately 6 minutes of evacuation, the vacuum level in each inlet section stabilized, with pressure fluctuations not exceeding 0.001 MPa for 60 seconds. The stable pressure values ​​collected by the pressure sensor at this time are as follows: Import partition A: -0.092MPa, import partition B: -0.090MPa, import partition C: -0.091MPa.

[0049] Subsequently, a 10-minute pressure test was conducted while maintaining a vacuum state. During the test, the pressure rise in each inlet zone did not exceed 0.002 MPa, which was less than the preset allowable rise value of 0.005 MPa. Based on this, the inlet space was deemed to be sealed successfully.

[0050] 4. Resin System Preparation and Introduction This trial production used a low-viscosity resin system composed of epoxy resin and amine curing agent. After mixing, the resin was placed in a constant temperature oven and allowed to stand at 45℃ for 15 minutes to degas. After degassing, the resin was tested using a rotational viscometer, and the viscosity was measured to be approximately 320 mPa·s at 42℃.

[0051] Before resin introduction, the outlet temperature of the resin supply unit is set to 40-45℃, and the introduction pressure is stably controlled at 0.05MPa through the pressure regulating valve.

[0052] During the introduction process, pressure signals are collected by pressure sensors installed at the glue inlet and vacuum exhaust port of each introduction zone, and resin front arrival signals are collected by front-edge sensors placed at the end of each introduction zone.

[0053] Each import zone has one leading edge sensor on the end exhaust side, and they are arranged according to the same installation standard to ensure comparable arrival times.

[0054] 5. The actual occurrence and adjustment of imbalances After the resin introduction begins, the pressure value of each introduction zone and the arrival signal of the resin front are continuously recorded by the data acquisition system.

[0055] The pressure signal was acquired at a fixed sampling frequency. After 210 seconds of import, the instantaneous pressure values ​​of each import zone recorded by the system were as follows: Import partition A: 0.048MPa, import partition B: 0.041MPa, import partition C: 0.044MPa.

[0056] At this time, the pressure difference between imported partition A and imported partition B is 0.007MPa, which exceeds the preset first threshold of 0.005MPa.

[0057] Meanwhile, the leading edge sensor located at the end of the import partition recorded that the resin leading edge of import partition B arrived 95 seconds later than that of import partition A, exceeding the preset second threshold of 60 seconds.

[0058] The first and second thresholds are control thresholds pre-set based on the product's structural characteristics and prior process trial experience. Based on the aforementioned real-time collected pressure difference and leading edge arrival time difference data, an imbalance was determined to have occurred during the introduction process.

[0059] After determining the imbalance, the following conditional actions are performed by controlling the valve assembly: Open the bypass connection channel between import partition A and import partition B, and at the same time reduce the valve opening of the glue inlet passage of import partition A by about 20% from the original setting value relative to the setting before adjustment.

[0060] After the bypass connection channel was opened, the pressure changes of each inlet section were continuously monitored. After about 70 seconds, the pressure difference between inlet section A and inlet section B was recorded to drop below 0.003 MPa, and at the same time, the time difference between the resin front arrival times of the two inlet sections decreased.

[0061] Approximately 70 seconds after the bypass is activated, the time difference between the leading edges of partitions A and B decreases from 95 seconds to approximately 35 seconds.

[0062] When the pressure difference and the time difference of the leading edge do not exceed the corresponding threshold within 30 consecutive seconds, the bypass connection channel is closed, and each import partition resumes independent import status.

[0063] 6. Import Results and Product Status Under the above adjustment and control, the time for each import partition to complete the full cavity filling is as follows: import partition A: 620s, import partition B: 655s, import partition C: 640s.

[0064] After the injection is completed, the vacuum boundary conditions inside the mold are maintained, and subsequent heat curing is performed. After demolding, the product is visually inspected and ultrasonically tested. The results show that no dry spots or porosity defects were detected in the thick-walled area and the area where the ribs intersect.

[0065] In summary, during the resin introduction process, when the pressure difference or resin front arrival time difference between different introduction zones exceeds a preset threshold, by opening the bypass connecting channels between the introduction zones and adjusting the injection path, the introduction state of each introduction zone can gradually become consistent, thereby controlling the mold filling time difference between the introduction zones within a small range. Actual molding and testing results show that the resin introduction method can achieve complete mold filling in complex structural areas such as thick-walled areas and rib intersections, without observing dry spots or obvious porosity defects. This indicates that under the process conditions of this embodiment, the above-mentioned dynamically adjusted resin introduction method can complete the mold filling of thick-walled areas and rib intersection areas.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency molding process for fiberglass composite materials, characterized in that, include: S1. Lay up glass fiber reinforced material to form a preform and place it in the cavity of a mold, and set a sealing structure to form a vacuum-capable inlet space; S2. Based on the three-dimensional structural model or engineering drawing of the product, determine the thick-walled area and the geometrically complex area in advance. Divide the thick-walled area and the geometrically complex area into at least two independent inlet sections in the cavity. Set a corresponding resin inlet and vacuum outlet for each inlet section. Connect each inlet section to the resin supply unit and the vacuum suction unit independently through the valve group. Set a bypass connection channel between adjacent inlet sections, which is controlled by the partition valve. S3. After evacuating each inlet section to the target vacuum level and completing pressure holding and leak detection, start the resin supply unit to introduce the resin system into each inlet section. During the introduction process, collect the pressure detection signal and the resin front arrival signal of each inlet section. Use the pressure difference between any two inlet sections being greater than the first threshold or the time difference of the resin front arrival signal being greater than the second threshold as the imbalance criterion. When the imbalance criterion is triggered, control the valve group to adjust the glue injection passage or suction passage of each inlet section in a zone, and selectively open or close the bypass connection channel so that each inlet section meets the requirement that the pressure difference does not exceed the first threshold or the time difference does not exceed the second threshold during the introduction until the full cavity filling is completed. S4. After filling the entire cavity with mold, maintain the vacuum boundary conditions of the introduction space, start the mold heating unit to rapidly cure the resin system in the mold to the demolding strength according to the preset temperature rise curve, and then open the mold to obtain the fiberglass composite material product.

2. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The thick-walled region is the area in the three-dimensional structural model or engineering drawing of the product where the local wall thickness is greater than or equal to a preset thick-walled threshold. The geometrically complex region is the area in the three-dimensional structural model or engineering drawing of the product that satisfies any of the following structural features: dense ribs, abrupt changes in cross-section, narrow flow channels, deep concave cavities, sharply turning flow channels, or semi-closed cavities formed by local enclosure.

3. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The division of the import partitions satisfies the following principles: the thick-walled area or the geometrically complex area is used as a separate import partition, or the thick-walled area or the geometrically complex area is divided into different import partitions, and the shortest resin flow path length from the corresponding resin inlet to any filling position in the corresponding import partition is not greater than the preset maximum flow path threshold.

4. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The resin inlet of the import partition is located on the priority filling side of the corresponding import partition, and the vacuum exhaust port is located on the end exhaust side opposite to the resin inlet. A flow guiding medium is provided between the resin inlet and the preform. The flow guiding medium is laid along the preset main flow direction and covers at least one resin front edge to the signal acquisition position.

5. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The target vacuum degree is a gauge pressure negative pressure state and not lower than -0.08MPa. The pressure holding and leak detection includes: maintaining the vacuum state for a preset leak detection time after reaching the target vacuum degree, and determining that the pressure holding and leak detection is completed when the pressure rise value of the introduced space does not exceed the preset allowable rise value within the preset leak detection time.

6. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The pressure detection signal is collected by pressure sensors respectively installed at the vacuum exhaust port or resin inlet of each inlet section; the resin leading edge arrival signal is collected by a leading edge sensor installed at a predetermined monitoring position in each inlet section, and the leading edge sensor is any one of an electrode conduction sensor, an optical fiber sensor or a dielectric response sensor.

7. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: When the imbalance criterion is triggered, the partition adjustment includes: opening the bypass connection channel to perform inter-partition pressure equalization, and closing the bypass connection channel when the pressure difference does not exceed a first threshold and the time difference does not exceed a second threshold.

8. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The resin system is a curable resin composition used to impregnate the preform and can be cured in the mold to form a resin matrix. The resin system includes a matrix resin and a curing component. Before performing step S3, the resin system is degassed and the introduction temperature of the resin system is controlled within a preset temperature range.

9. The efficient molding process for fiberglass composite materials according to claim 1, characterized in that: The preset heating curve includes a heating stage and a heat preservation stage: heating to a preset curing temperature and maintaining the heat preservation time for a preset duration; The demolding strength is determined by any of the following demolding criteria: the in-mold dielectric curing degree reaches the preset curing degree criterion, the in-mold temperature-time integral reaches the preset curing completion criterion, and the product surface hardness reaches the preset hardness criterion.

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