Vacuum infusion mould assembly and method for wind turbine blade pultruded spar without sanding

Abstract

The application provides a polishing-free vacuum infusion forming mold assembly and method for a wind power blade pultrusion main beam, the mold assembly comprising: a mold body, a fixed baffle and a triangular cross-section positioning structure; the fixed baffle is arranged on the lower side of the mold body; the triangular cross-section positioning structure comprises a triangular cross-section support body, which is arranged on the mold body at a position without the fixed baffle and closely arranged on the side edge of the pultrusion plate. The application can effectively improve the adhesion of the vacuum bag film and the side edge of the main beam, prevent the accumulation of resin on the beam edge after curing, save the resin cleaning process on the side edge, and thus improve the forming quality and production efficiency.

Description

Technical Field

[0001] This invention relates to the field of non-metallic composite material processing and molding technology, and more specifically, to a grinding-free vacuum injection molding die assembly and method for pultruded main beams of wind turbine blades. Background Technology

[0002] In the field of wind turbine blade manufacturing, pultruded main beams have been widely used in large-scale, long blade structures due to their advantages such as high strength, high modulus, lightweight, and scalability. The current mainstream process is "pultruded sheet prefabrication + vacuum infusion molding," which involves first laying multi-layer carbon fiber / glass fiber pultruded sheets in a mold body according to the design, and then achieving integral curing through vacuum-assisted resin infusion (VARI). Although this process has advantages such as high efficiency and excellent material utilization, it still faces several key technical bottlenecks in practical engineering applications, among which the problem of resin overload on the sides is particularly prominent.

[0003] Traditional pultruded main beam prefabrication typically employs a double-sided or single-sided continuous fixed baffle structure, using metal or composite material baffles to constrain the lateral displacement of the pultruded sheet during the injection process and help control the resin flow boundary. However, in actual production, due to inherent straightness deviations in the pultruded sheet itself (such as wavy edges, warping, etc.), it is difficult to achieve a tight fit between it and the continuous fixed baffle throughout the entire process. Simultaneously, minor unevenness on the mold surface, installation errors of the fixed baffles, and non-uniform stress distribution during vacuum bag film tightening further exacerbate the formation of local gaps. Under vacuum negative pressure, resin tends to flow excessively to the sides along these gaps and accumulate, forming resin-rich areas with excessive thickness and low fiber content. This defect not only significantly reduces the structural strength and fatigue performance of the main beam's side edges but also necessitates manual or mechanical grinding after demolding. This process is time-consuming, labor-intensive, and generates severe dust pollution, and it easily causes fiber damage or dimensional deviations, seriously affecting product consistency and batch delivery efficiency.

[0004] Furthermore, existing improvement solutions mostly focus on optimizing the material of the fixed sidewalls, adding elastic sealing structures, or introducing dynamic adjustment mechanisms, but they generally suffer from high costs, poor adaptability, and complex maintenance. Some attempts have also been made to use foam core materials or soluble support blocks as lateral restraints, but these have drawbacks such as deformation under high-temperature curing, residue pollution, and difficulty in recycling. Especially for the main beams of modern wind turbine blades with large aspect ratios and significant variable cross-sections, the geometric parameters from the root to the tip change drastically, placing higher demands on the modularity, adjustability, and process robustness of the lateral support structure.

[0005] Chinese patent CN114043747A discloses a method for eliminating the need for grinding on the main beam of wind turbine blades. This method involves placing right-angle strips sequentially at the corners on both sides of all fiberglass cloth layers on the main beam, eliminating cloth layer accumulation during the layup process and thus achieving a beam without edge curling after molding. This patent primarily addresses the problem of edge curling on the upper surface of manually laid fiberglass cloth-filled main beams.

[0006] Therefore, there is a need for a pultruded main beam prefabrication mold assembly and method that is simple in structure, easy to implement, highly compatible, and requires no subsequent grinding, so as to fundamentally suppress the phenomenon of resin enrichment on the sides and improve the level of automation and green manufacturing capabilities while ensuring structural performance. Summary of the Invention

[0007] The purpose of this invention is to provide a non-grinding vacuum infusion molding die assembly and method for pultruded main beams of wind turbine blades. It employs a combination of "single-sided intermittent fixed sidewalls + PET triangular blocks" to replace the traditional continuous fixed sidewall design, effectively controlling the deformation of the vacuum bag film and preventing localized resin accumulation. After molding, the main beam has smooth sides without resin-rich defects, meeting the non-grinding requirement. Vacuum pressure holding and infusion stability meet standards, and the process repeatability is good.

[0008] To achieve the above objectives, this invention provides a grinding-free vacuum injection molding die assembly and method for pultruded main beams of wind turbine blades. The technical solution of this invention is implemented as follows:

[0009] A non-grinding vacuum injection molding die assembly for a pultruded main beam of a wind turbine blade includes:

[0010] Mold body;

[0011] A fixed retaining edge is provided on the lower side of the mold body;

[0012] A triangular cross-section positioning structure includes a triangular cross-section support body, which is disposed on the mold body, located at a position without the fixed sidewall, and closely attached to the side of the pultrusion plate.

[0013] Furthermore, multiple fixed baffles are provided at intervals along the length direction.

[0014] Furthermore, the fixed flange has a right-angled trapezoidal cross section, with the right-angled side fitting against the side of the pultruded plate.

[0015] Furthermore, the height of the fixed baffle is consistent with the thickness of the main beam to be formed, and its start and end positions smoothly transition to zero along the length direction.

[0016] Furthermore, the triangular cross-section support is a PET triangular block with a right-angled triangular cross-section, and its right-angled side is attached to the side of the pultruded plate.

[0017] Furthermore, the triangular cross-section support is wrapped with a non-porous insulating membrane.

[0018] Furthermore, the length of the fixed edge is 200mm~300mm, and the distance between two adjacent fixed edges is 4m~6m.

[0019] Furthermore, the length of the two right-angled sides of the PET triangular block cross-section is 10mm~15mm, the length of the hypotenuse is 14mm~21mm, and the length of a single piece is 1m~1.5m.

[0020] A method for vacuum casting molding of pultruded main beams for wind turbine blades without grinding, comprising the following steps, using the mold assembly described above to prepare the pultruded main beams for wind turbine blades.

[0021] S1, Prepare the mold body and set a single-sided fixed stop on the lower side of the mold body;

[0022] S2, Demolding system construction;

[0023] S3, pultruded sheet and interlayer reinforcement;

[0024] S4, Active adjustment of side profile: In the main body area of ​​the mold without fixed sidewalls, a triangular cross-section support body wrapped with a non-porous isolation membrane is arranged closely to the side of the pultrusion plate;

[0025] S5, vacuum infusion system integration and curing molding.

[0026] Furthermore, in step S4, multiple sets of PET triangular blocks are set along the length of the main beam in the front and rear edge areas of the main beam to be formed and in the gap section without fixed baffles between the two fixed baffles. Two adjacent PET triangular blocks are connected end to end to form a continuous strip and are connected to the fixed baffles in the length direction.

[0027] Compared with the prior art, the dust-free vacuum injection molding die assembly and method for pultruded main beams of wind turbine blades described in this invention have the following advantages:

[0028] 1. Completely eliminates resin accumulation on the sides. Through a synergistic limiting structure of "single-sided intermittent fixed sidewall + PET triangular block," the deformation path and bonding state of the vacuum bag film are precisely controlled, avoiding local gaps caused by straightness deviations in the pultrusion plate in traditional continuous fixed sidewalls. This fundamentally blocks the channel for abnormal resin migration to the sides. The single-sided intermittent fixed sidewall offers high molding reliability, solving the strong dependence on mold precision inherent in traditional continuous structures.

[0029] 2. Truly eliminates the need for grinding. After molding, the main beam has uniform fiber distribution, a smooth contour, and no resin buildup. No grinding process is required after demolding, significantly reducing labor costs, dust pollution, and the risk of fiber damage.

[0030] 3. Strong process compatibility and simple implementation. This invention does not rely on high-precision mold modification or the addition of complex equipment. It only introduces a standardized PET triangular block and intermittent fixed sidewall layout into the existing vacuum infusion process to adapt to main beams of different lengths and variable cross-sections.

[0031] 4. Improved molding efficiency and quality consistency. This invention eliminates the grinding process, shortening the manufacturing cycle. Simultaneously, the PET triangular blocks exhibit stable dimensions, good thermal stability, and repeatable positioning, ensuring high consistency in geometric accuracy and surface quality between batches.

[0032] 5. Green and low-carbon, with low engineering costs. PET materials are recyclable and have no chemical residues or high-temperature decomposition products; the overall solution is based on the upgrading of mature auxiliary materials, requiring no additional investment in specialized equipment, and has a good foundation for industrialization and promotion. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a typical cross-sectional arrangement of the pultruded main beam of the wind turbine blade as described in Embodiment 1 of the present invention.

[0034] Figure 2 This is a schematic diagram of the vacuum injection molding structure of the pultruded main beam of the wind turbine blade according to Embodiment 1 of the present invention.

[0035] Explanation of reference numerals in the attached figures.

[0036] 1. Release cloth; 2. Evacuation pipe; 3. PET triangular block; 5. Perforated release film; 6. Flow guide net; 8. Fixed side guard; 9. Mold body; 10. Main beam product; 41. Flow blocking tape one; 42. Flow blocking tape two; 71. Injection tube one; 72. Injection tube two. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0038] Example 1

[0039] This embodiment provides a grinding-free mold assembly specifically for vacuum injection molding of pultruded main beams for large wind turbine blades. It constructs a composite constraint system of unilateral rigid restraint and local precise shaping, fundamentally eliminating the resin-rich side defects caused by the collapse of the vacuum bag film in unsupported areas in traditional processes. This results in straight sides, a smooth surface without protrusions, and no need for any mechanical grinding after the main beam is demolded.

[0040] The no-grind vacuum infusion molding die assembly for the pultruded main beam of wind turbine blades includes: a die body 9, a fixed baffle 8, and a triangular cross-section positioning structure. The die body 9 provides macroscopic surface support; the fixed baffle 8 undertakes the main lateral limiting and initial contour definition; the triangular cross-section support body, under vacuum negative pressure, is forcibly covered with a vacuum bag film and precisely shaped along its hypotenuse. The three components form a "main-auxiliary-micro" three-level spatial constraint chain, which physically confines the resin flow front in the side region within the theoretical contour, completely blocking the resin-rich generation path and achieving the no-grind effect.

[0041] The main body 9 of the mold is a long strip-shaped base mold made of steel or high-rigidity composite material, with curved cavities that precisely match the aerodynamic shape of the main beam, including PS surface and SS surface.

[0042] The fixed flange 8 is positioned along the length of the mold body 9 on one side of the main beam to be formed. Preferably, it is positioned on the lower side of the mold body 9, i.e., the side that naturally sinks due to gravity, serving as the first-level geometric reference for the side of the main beam. Utilizing gravity-assisted positioning significantly improves the stability during the stacking of multilayer pultruded plates and prevents layer displacement.

[0043] Multiple fixed baffles 8 are spaced apart along the length. This intermittent layout of the fixed baffles 8 reduces the system's dependence on the overall straightness of the mold. Even with minor wavy deformation of the mold, each independent fixed baffle 8 can still independently perform its limiting function, significantly enhancing process tolerance and production line adaptability. The fixed baffle 8 has a right-angled trapezoidal cross-section, with the right-angled side fitting against the side of the pultrusion plate for limiting and shaping. The beveled side facilitates adjustment of the vacuum bag film to prevent it from tearing during vacuuming due to misfitting.

[0044] Specifically, the length of the fixed baffle 8 is 200mm to 300mm, balancing local rigidity and adaptability to thermal deformation. Too short a length would result in insufficient support, while too long a length would easily lead to bending deformation due to thermal expansion and contraction of the mold. The spacing between two adjacent fixed baffles 8 is 4m to 6m, matching the standard length (1~1.5m) of the PET triangular blocks 3 and the mainstream vacuum zoning logic, ensuring that each section without fixed baffles 8 is fully covered by several PET triangular blocks 3, eliminating blind spots in the molding process. After bonding, the angle of the fixed baffle 8 relative to the ground is 90° to 91°, ensuring the pultruded beam adheres to the fixed baffle 8 while preventing it from being pulled off during demolding. The height of the fixed baffle 8 is consistent with the thickness of the main beam to be molded, and its start and end positions gradually transition to zero in the height direction in a linear or arc-shaped transition section, facilitating the adhesion of the bag film during vacuuming and preventing air leakage.

[0045] The triangular cross-section positioning structure includes a triangular cross-section support, which is positioned in the mold body 9 area without fixed sidewalls 8, closely attached to the side of the pultruded plate. Preferably, the triangular cross-section support is a PET triangular block 3 with a right-angled triangular cross-section, which fits tightly against the vertical side surface of the pultruded plate with its right-angled sides, forming a second-level dynamic shaping reference. PET material has excellent dimensional stability, high bending stiffness, and resistance to epoxy resin chemical corrosion; its right-angled triangular cross-section can simultaneously constrain the horizontal displacement and vertical warping of the pultruded plate side, locking the side spatial posture at the moment of vacuum tightening, preventing local bulging caused by resin buoyancy or flow impact during the injection process, and is a key rigid support point for achieving "zero resin enrichment" on the side. The triangular cross-section positioning structure may also include shallow grooves or magnetic / clamp-type limiting seats on the mold surface to fix the position of the triangular cross-section support and ensure its tight fit with the side of the pultruded plate.

[0046] The triangular cross-section support is wrapped with a non-porous release membrane. The non-porous release membrane forms a completely inert barrier, which on the one hand prevents any interfacial reaction or small molecule migration between PET and epoxy resin system, ensuring resin purity and curing performance; on the other hand, it ensures that the triangular block can be peeled off whole, without damage or residue, during demolding, can be reused, reduces auxiliary material costs and avoids debris contamination of the main beam surface.

[0047] Specifically, the lengths of the two right-angled sides of the PET triangular block 3 section are 10mm to 15mm, and the length of the hypotenuse is 14mm to 21mm, covering the typical tolerance zone (12±0.5mm) of the main beam side, ensuring a tight fit between the support height and the theoretical profile. The length of a single PET triangular block 3 is 1m to 1.5m, matching the effective control range of the injection channel, reducing the number of joints, and avoiding millimeter-level step errors introduced by multi-segment splicing. Actual measurements show that when using a 1.2m single triangular block, the standard deviation of the main beam side profile is reduced by more than 80% compared to traditional processes.

[0048] Figure 1This diagram illustrates a typical cross-sectional layout for vacuum injection molding of the pultruded main beam of a wind turbine blade, showcasing the spatial arrangement of key components from the blade root (leading edge LE) to the blade tip (trailing edge TE). A represents the distance from the extraction pipe 2 to the leading edge end; B represents the distance from the edge of the guide net 6 to the leading edge end; C represents the distance from the flow-restricting tape 42 to the leading edge end; D represents the distance from the injection pipe to the trailing edge end; and E represents the distance from the flow-restricting tape 41 to the trailing edge end. a, b, c, d, and n represent the areas formed by segmenting the pultruded plate along the length of the main beam according to different functional priorities. The PET triangular block 3 has a right-angled triangular cross-section, wrapped with a non-porous release film, used to support the vacuum bag film and prevent collapse leading to resin enrichment. Flow-restricting tapes 41 and 42 are adhered to the surface of the guide net 6, forming a resin flow boundary to prevent resin diffusion into non-target areas, especially acting as a "flow-limiting valve" in the leading and trailing edge regions. The perforated separator 5 and the flow guide 6 are porous material layers that allow resin to pass through while blocking fiber movement, promoting uniform resin distribution and air bubble removal. Injection tube 1 71 and injection tube 2 72 are resin injection channels located on the rear edge TE side and the middle (d area), respectively, enabling dual-point resin supply and improving injection efficiency. The fixed baffle 8 is a rigid structural component located on one side of the mold body 9, with a height equal to the main beam thickness, used to maintain the side shape and, together with the PET triangular block 3, achieves full circumferential constraint. The release cloth 1 is laid above the pultrusion plate to prevent the composite material from adhering to the vacuum bag film, facilitating demolding.

[0049] In terms of spatial layout, the entire process of "venting → support → flow guidance → resin injection → convergence → shaping" is completed sequentially from the leading edge LE to the trailing edge TE. The PET triangular block 3 and the fixed baffle 8 form a "segmented rigid constraint chain," which overcomes the problem that traditional continuous fixed baffles 8 cannot adapt to large-span molds. The flow-blocking tape enables precise control of the resin flow path, avoiding waste and defects. The air extraction pipe 2 and the resin injection pipe are rationally distributed to ensure rapid vacuum establishment and uniform resin flow.

[0050] This mold assembly is not a simple stacking of parts, but rather a design based on geometric precision transfer, controllable mechanical state, and interface behavior isolation. It organically couples the macro mold, meso fixed sidewall 8, and micro support body to form a closed-loop side quality assurance system, providing an engineeringable core hardware foundation for the efficient, reliable, and green manufacturing of high-value carbon fiber pultruded main beams.

[0051] This mold assembly precisely controls the bonding state. Through a combination strategy of "intermittent fixed sidewalls 8 + PET triangular blocks 3," it optimizes vacuum bonding performance while maintaining structural strength. It avoids localized stress concentration, and the discontinuous fixed sidewalls 8 reduce the constraint force on the pultruded plate, lowering the risk of cracking caused by thermal expansion and contraction or inconsistent deformation. Simultaneously, it achieves the goal of eliminating the need for sanding. Since there is no resin buildup on the sides, no additional processing is required after demolding to meet assembly requirements, significantly improving production efficiency. This mold assembly is suitable for complex cross-sectional changes and can flexibly adapt to main beams with different cross-sectional dimensions and degrees of curvature, exhibiting excellent versatility and expandability.

[0052] Example 2

[0053] This embodiment provides a vacuum injection prefabrication method for pultruded main beams (hereinafter referred to as "main beams") of 100-meter-class wind turbine blades. Through structural constraints and precise deformation control, the resin-rich defects on the sides are completely eliminated, and mechanical grinding is not required after demolding, ensuring the surface integrity, dimensional accuracy and batch consistency of the carbon fiber pultruded plate.

[0054] The specific steps are as follows:

[0055] S1, mold preparation and installation of single-sided intermittent fixed edge 8.

[0056] S11. Clean the surface of the main beam mold body 9, remove oil, dust and residual release agent, and ensure that the mold base surface is clean, dry and free of scratches.

[0057] S12, on the lower side of the mold body 9, i.e., the side naturally hanging down due to gravity, along the length of the mold body 9, fixed retaining edges 8 are bonded and fixed at intervals of 4m to 6m. The cross-section of the fixed retaining edges 8 is a right trapezoid, and the material is high-temperature resistant polyurethane elastomer. The length of each fixed retaining edge 8 is 200mm to 300mm, and the height is consistent with the theoretical height of the side of the target main beam. It transitions smoothly from the starting end to the end with a height of 0mm. The overall tilt angle is strictly controlled between 90° and 91°, i.e., nearly vertical, with a slight outward tilt of ≤1°.

[0058] Specifically, the rear edge of the 0-7m area on the PS surface is lower, while the front edge of other areas is lower; the rear edge of the SS surface is lower overall. The specific bonding positions of the fixed edge 8 and the corresponding heights of the fixed edge 8 are shown in the table below.

[0059]

[0060] The layout of the single-sided fixed baffle 8 avoids the strict dependence on the straightness of the mold that is required by the traditional double-sided continuous fixed baffle 8; the micro-tilt design ensures that the vacuum bag film fits the main beam side wall in an appropriate manner when it is tightened, and avoids the displacement of the PET triangular block 3 or local stress concentration due to excessive compression, while also preventing the fixed baffle 8 from being taken off during demolding; the intermittent setting provides precise embedding space for the subsequent PET triangular block 3, while reducing the risk of system deformation caused by thermal expansion and contraction of the mold.

[0061] S2, Demolding system construction.

[0062] S21. Apply water-based silicone release agent evenly to the working surface of the mold body 9 and the surface of the installed fixed edge 8, and let it stand to dry until it is no longer sticky to the touch.

[0063] S22, then lay another layer of polyester-based release cloth 1, flatten and compact it to ensure no air bubbles, no wrinkles, and no hanging edges, especially at the junction of the fixed edge 8 and the mold body 9, it must be completely covered without gaps. Specifically, lay an 800mm wide release cloth 1 on the surface of the mold body 9, with the excess part at the front and rear edges turned over to the outside of the fixed edge 8.

[0064] To form a stable, low-adhesion interface, ensuring that all subsequent auxiliary materials can be completely peeled off; the full coverage of the release cloth 1 also provides a uniform support benchmark for the vacuum bag film, preventing local collapse from causing resin flow disorder.

[0065] S3, pultruded sheet and interlayer reinforcement.

[0066] S31, according to process requirements, the carbon fiber / epoxy resin pultruded sheet is cut into sections.

[0067] S32, pultruded sheets are laid layer by layer at a chamfer ratio of 1:100. After each layer is laid, a layer of bidirectional woven interlayer fabric (2AX-0200) is immediately placed on top. The tangential direction (blade span direction) of this fabric extends 5-10mm beyond the edge of the pultruded sheet, and the axial direction (blade root to blade tip direction) extends 20-50mm beyond the next layer, forming a stepped overlap. The interlayer fabric not only improves the interlayer shear strength in the thickness direction, but more importantly, its capillary channels can guide the resin to penetrate evenly along the thickness direction, inhibiting resin sluggishness caused by the dense structure of the pultruded sheet. The extra-wide tangential design provides a buffer zone for side vacuum sealing, and the axial stepped overlap effectively disperses the resin impact force at the injection front, preventing sheet displacement.

[0068] S33, after the pultruded plates are stacked, they are placed in the mold body 9. The overall position is calibrated with the positioning reference line at the root of the main beam as the origin, and the deviation is no greater than ±1.5mm. Specifically, according to the meter mark and process requirements marked on the mold body 9, the stacked pultruded plates are positioned with a starting position of 1.5m from the root of the mold body 9.

[0069] S4, active adjustment of side profile.

[0070] S41, on both sides (the side without fixed flange 8) and the top surface of the pultruded plate stack, release cloth 1 is laid again to tightly fit all edges and curved surfaces.

[0071] S42, in the front and rear edge (LE / TE) areas and the gap section without fixed guards 8 between the two fixed guards 8, multiple sets of PET triangular blocks 3 are arranged along the length direction. Two adjacent PET triangular blocks 3 are connected end to end to form a continuous strip, and are connected to the fixed guards 8 in the length direction, such as... Figure 2 As shown. The PET triangular block 3 has a right-angled triangle cross-section, laser-cut from 0.5mm thick food-grade PET sheet, with right-angled sides of 10mm~15mm, hypotenuse of 14mm~21mm, and a single piece length of 1m~1.5m. Before placement, the PET triangular block 3 is completely wrapped in a non-porous release film and heat-sealed; during placement, ensure that one right-angled side of the PET triangular block 3 is in close contact with the side face of the pultrusion plate, and the other right-angled side rests on the bottom surface of the mold, forming an L-shaped support.

[0072] The PET triangular block 3 acts as a rigid support. Under vacuum negative pressure, the upper vacuum bag film is forced to precisely form along its inclined surface, thus "replicating" the side geometry consistent with the theoretical outline of the main beam in the area without fixed sidewalls 8. The non-porous isolation film wrapping not only prevents the PET from absorbing moisture and deforming, but also ensures complete isolation from the resin system and zero pollution. After demolding, the whole piece can be recycled and reused.

[0073] S5, vacuum infusion system integration and curing.

[0074] S51, lay the perforated isolation membrane 5, the flow guide net 6, the spiral injection tube, the air extraction tube 2 and the flow-blocking tape in sequence, covering the entire circumference along the front and rear edge sealing lines.

[0075] S52, use a vacuum bag film to seal the entire system, evacuate to a system pressure ≤−0.095MPa, hold the pressure for 10 minutes, and check for pressure decay ≤0.002MPa to confirm that there is no leakage in the system.

[0076] S53 is injected with low-viscosity epoxy resin at a constant flow rate. After injection, it is heated and cured, and then the vacuum is broken after cooling to room temperature.

[0077] S54, remove the perforated isolation membrane 5, the guide net 6 and other auxiliary materials in sequence, and take out the PET triangular block 3 to obtain the pultruded main beam product 10 with flat sides.

[0078] The PET triangular block 3 maintains geometric stability throughout the process, controlling the resin flow front and ensuring uniform thickness distribution in the side area. This results in a smooth, burr-free, resin-free, and pore-free surface that requires no sanding. Coordinate measuring machine (CMM) testing and visual inspection confirm that it meets the standard's acceptance requirements for the appearance and dimensions of the main beam's side.

[0079] This embodiment fundamentally solves the problem of resin-rich sides of pultruded main beams from three dimensions: physical constraints, morphology replication, and flow field control, through the coordinated use of structured fixed sidewall layout, rigid triangular block active shaping, and high-stability vacuum infusion. It truly achieves "one-time molding, no grinding, and zero rework", significantly improving the utilization rate of high-value carbon fiber materials and the intelligent manufacturing level of large blade main beams.

[0080] This method has been successfully verified in the trial production of a certain type of blade main beam, with a yield rate of over 95%. The forming cycle of a single main beam is significantly shortened compared to the traditional grinding process, and no fiber damage or interlayer delamination caused by grinding occurs.

[0081] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A non-grinding vacuum injection molding die assembly for a pultruded main beam of a wind turbine blade, characterized in that, include: Mold body (9); A fixed flange (8) is provided on the lower side of the mold body (9); The triangular cross-section positioning structure includes a triangular cross-section support body, which is disposed on the mold body (9), located in a position without the fixed sidewall (8), and closely attached to the side of the pultrusion plate.

2. The mold assembly according to claim 1, characterized in that, The fixed guard (8) is provided at intervals along the length direction.

3. The mold assembly according to claim 1, characterized in that, The fixed baffle (8) has a right-angled trapezoidal cross section, with the right-angled side fitting against the side of the pultruded plate.

4. The mold assembly according to claim 1, characterized in that, The height of the fixed baffle (8) is consistent with the thickness of the main beam to be formed, and its starting and ending positions smoothly transition to zero along the length direction.

5. The mold assembly according to claim 1, characterized in that, The triangular cross-section support is a PET triangular block (3) with a right-angled triangular cross-section, and its right-angled side is attached to the side of the pultruded plate.

6. The mold assembly according to claim 1, characterized in that, The triangular cross-section support is wrapped with a non-porous insulating membrane.

7. The mold assembly according to claim 2, characterized in that, The length of the fixed edge (8) is 200mm~300mm, and the distance between two adjacent fixed edges (8) is 4m~6m.

8. The mold assembly according to claim 5, characterized in that, The length of the two right-angled sides of the PET triangular block (3) is 10mm~15mm, the length of the hypotenuse is 14mm~21mm, and the length of a single piece is 1m~1.5m.

9. A method for grinding-free vacuum casting molding of pultruded main beams for wind turbine blades, characterized in that, The fabrication of pultruded main beams for wind turbine blades using the mold assembly described in any one of claims 1 to 7 includes the following steps: S1, the mold body (9) is prepared, and a single-sided fixed flange (8) is set on the lower side of the mold body (9). S2, Demolding system construction; S3, pultruded sheet and interlayer reinforcement; S4, Active control of side shape: In the area of ​​the mold body (9) without fixed sidewall (8), a triangular cross-section support body wrapped with a non-porous isolation membrane is arranged close to the side of the pultrusion plate; S5, vacuum infusion system integration and curing molding.

10. The method according to claim 9, characterized in that, In step S4, multiple sets of PET triangular blocks (3) are set along the length of the main beam in the front and rear edge areas of the main beam to be formed and in the gap section without fixed sidewalls (8) between the two fixed sidewalls (8). Two adjacent PET triangular blocks (3) are connected end to end to form a continuous strip and are connected with the fixed sidewalls (8) in the length direction.

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