A composite material molding die with embedded parts and its manufacturing method

Abstract

This invention discloses a composite material molding die with embedded parts and its manufacturing method, relating to the field of composite material molding technology. The composite material molding die with embedded parts includes a first embedded part region with a first embedded part and a non-embedded part region without the first embedded part. The first embedded part region, along the thickness direction of the die, sequentially includes: a gel coat layer, a first structural layer, a thermally conductive diffusion layer, a second structural layer, and a thermal buffer layer. The thermal buffer layer is compositely disposed on the outer surface of the second structural layer and covers the end of the first embedded part away from the molding surface. This invention provides a composite material molding die with embedded parts, in which a thermally conductive diffusion layer and a thermal buffer layer are provided in the first embedded part region. Through the synergistic effect of lateral diffusion and thickness-direction thermal insulation, the local heat flux density is reduced and the temperature gradient is smoothed, avoiding overheating and thermal stress concentration in the embedded part region, thereby improving the thermal stability of the die and the consistency of the molded part's precision.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, and more specifically, to a composite material molding die with embedded parts and a method for manufacturing the same. Background Technology

[0002] Composite material molding dies are widely used in the molding and manufacturing process of carbon fiber composite products. To meet the needs of installation, positioning, or subsequent assembly of the molded parts, existing composite material molding dies typically have a first embedded part on the die body. This first embedded part is used to position a second embedded part on the molded part during the molding process. In the prior art, the first embedded part is usually made of metal, with one end flush with the molding surface of the die, and the other end exposed on the back or non-molding side of the die to facilitate assembly or positioning operations during the molding process.

[0003] In the molding process of carbon fiber composites, the composite material material laid on the mold usually needs to be heated and cured in a vacuum environment. Existing composite molding dies mostly adopt a carbon fiber and glass fiber composite laminate structure to balance strength and cost. However, carbon fiber composites exhibit significant anisotropy; their thermal conductivity in the direction perpendicular to the fibers is typically only 0.3–1.0 W / (m·K), while the thermal conductivity of titanium alloy materials commonly used in the first embedded part can reach 6–8 W / (m·K), showing a significant difference in thermal conductivity.

[0004] During the actual molding process, the mold heats up along with the ambient temperature. The mold portion covered by the composite material is located inside the entire vacuum system, and external heat needs to be conducted sequentially through the vacuum bag and the composite material layer to the mold body. Since one end of the first embedded part on the mold is covered by the composite material and the other end is exposed on the non-molding side of the mold, and the second embedded part on the molded part is also made of metal, during the heating and curing process, heat will preferentially be conducted along the metal embedded part, forming a local high thermal conductivity channel. This makes the heating rate of the area around the first embedded part significantly higher than that of the area in the mold without the first embedded part.

[0005] The aforementioned differences in thermal conductivity result in significant temperature gradients in localized areas of the mold and molded parts during heating and curing. This leads to inconsistent resin reaction rates and uneven stress release during the curing stage, consequently causing defects such as localized warping and deformation in the molded parts. This problem is particularly pronounced in molds with complex shapes and significant surface variations, severely impacting the dimensional accuracy and overall quality of the molded parts and limiting the stability and applicability of composite material molding dies. Summary of the Invention

[0006] In response to the common problems of local heat concentration and excessive temperature gradient in the thickness direction of the mold when setting metal embedded parts in existing composite material molding molds, especially during heating curing or cyclic use, the significant difference in thermal conductivity between the embedded parts and the surrounding composite materials can easily cause local overheating, thermal stress concentration, deformation, or even cracking of the mold, thereby affecting the molding accuracy, service life and product quality of the mold.

[0007] The present invention aims to provide a composite material molding die with embedded parts. A heat-conducting diffusion layer and a heat buffer layer are set in the first embedded part area. Through the synergistic effect of lateral diffusion and thickness direction heat insulation, the local heat flux density is reduced and the temperature gradient is smoothed, avoiding overheating and thermal stress concentration in the embedded part area, thereby improving the thermal stability, structural durability and consistency of the molded parts.

[0008] The present invention also proposes a method for manufacturing a composite material molding die with embedded parts.

[0009] To achieve the above objectives, the present invention provides a composite material molding die with embedded parts. The die is provided with one or more first embedded parts, and the die as a whole includes a first embedded part area with the first embedded parts and a non-embedded part area without the first embedded parts.

[0010] The first embedded part area includes, along the thickness direction of the mold, the following layers in sequence from the closest to the forming surface to the furthest from the forming surface: a gel coat layer, a first structural layer, a thermally conductive and diffusing layer, a second structural layer, and a thermal buffer layer; the thermal buffer layer is compositely disposed on the outer surface of the second structural layer and covers the end of the first embedded part furthest from the forming surface.

[0011] The non-embedded part area, along the thickness direction of the mold, includes, in sequence from the closest to the molding surface to the furthest from the molding surface: a gel coat layer, a first structural layer, and a second structural layer.

[0012] By introducing a combination of a heat-conducting diffusion layer and a heat-buffering layer in the embedded part area, the heat generated or transferred by the embedded part is diffused laterally and released longitudinally inside the mold, thereby ensuring the overall structural strength of the mold while achieving effective control of the local thermal field.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] 1. This invention provides a heat-conducting diffusion layer in the first embedded part area, enabling the heat generated and conducted outward during the heating and molding or use of the embedded part to diffuse laterally along the heat-conducting diffusion layer inside the mold. This transforms the point-like or localized heat transfer mode, which was originally concentrated around the embedded part, into a planar diffusion mode, significantly increasing the effective area for heat conduction. This reduces the heat flux density per unit area, slows down the local heating rate, avoids local overheating, resin thermal aging, or structural layer performance deterioration caused by heat accumulation near the embedded part, and improves the thermal stability of the embedded part area.

[0015] 2. This invention provides a heat buffer layer on the side away from the molding surface to isolate and release heat from the embedded parts and the heat-conducting diffusion layer. This makes the heat transfer process in the thickness direction of the mold smoother, thereby effectively reducing the temperature gradient in the thickness direction of the mold. It also reduces the risk of thermal stress concentration, increased interlayer shear stress and interface peeling caused by excessive temperature difference, and reduces warping, deformation or cracking of the mold during repeated thermal cycles.

[0016] 3. This invention addresses the differences in heating conditions and structural requirements between the embedded part area and the non-embedded part area by adopting a differentiated layered structure design. A heat-conducting diffusion layer and a heat buffer layer are introduced only in the area where the embedded part is located, while the conventional composite material structure layer arrangement is maintained in the non-embedded part area. This ensures the thermal management effect in the embedded part area while avoiding the overall mold structure from becoming too complex. It is beneficial to control the mold weight, material cost and manufacturing process difficulty, and improve the rationality of the mold design and the feasibility of the project.

[0017] 4. Through the synergistic effect of the heat-conducting diffusion layer and the heat buffer layer, the present invention can effectively control the heat distribution state of the embedded part area during the use of the mold, reduce the impact of thermal shock on the mold structure, thereby significantly improving the structural stability and durability of the mold under multiple heating and cooling cycles, extending the service life of the mold, and ensuring the uniformity of temperature distribution on the molding surface of the mold, which helps to improve the molding accuracy, dimensional consistency and surface quality of composite material products.

[0018] According to one embodiment of the present invention, the heat-conducting diffusion layer is disposed between the first structural layer and the second structural layer and arranged circumferentially along the first embedded part, so as to diffuse the heat generated by the first embedded part to the surrounding area, thereby reducing the local temperature difference between the embedded part and the adjacent structural layer and improving the uniformity of heat distribution inside the mold.

[0019] According to one embodiment of the present invention, the equivalent radius R1 of the heat-conducting diffusion layer and the equivalent radius R2 of the first embedded part satisfy R1≥1.5R2, and / or the thickness of the heat-conducting diffusion layer is 0.5~2.5mm. By reasonably limiting the coverage and thickness of the heat-conducting diffusion layer, the lateral heat diffusion efficiency is improved without significantly increasing the weight of the mold.

[0020] According to one embodiment of the present invention, the heat-dissipating diffusion layer is one of aluminum, copper, aluminum alloy or copper alloy. By utilizing the high thermal conductivity of the metal material, the heat diffusion capability of the embedded part area is further enhanced, and the thermal response speed is improved.

[0021] According to one embodiment of the present invention, the thickness of the heat buffer layer is 0.2 to 1.5 mm. By limiting the thickness of the heat buffer layer, effective heat insulation and buffering can be achieved while avoiding excessive overall thickness of the mold or insufficient structural rigidity.

[0022] According to one embodiment of the present invention, the heat buffer layer is made of silicone-based heat insulation material or ceramic fiber material. The above materials have both heat insulation properties and a certain degree of flexibility, which is beneficial to absorbing the stress generated by thermal expansion and contraction and reducing the risk of peeling between structural layers.

[0023] According to one embodiment of the present invention, the first structural layer includes a first carbon fiber layer and a first glass fiber layer, the second structural layer includes a second carbon fiber layer and a second glass fiber layer, and the thermally conductive diffusion layer is located between the first glass fiber layer and the second carbon fiber layer. By combining the glass fiber layer and the carbon fiber layer, the interlayer interface compatibility is improved while ensuring structural strength. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0025] Figure 1 This is a perspective view of the molding die in an embodiment of the present invention.

[0026] Figure 2 This is a top view of the molding die in an embodiment of the present invention.

[0027] Figure 3 for Figure 2 A cross-sectional view along line AA in the middle.

[0028] Figure 4 for Figure 3 A magnified view of a section at point B in the middle.

[0029] Explanation of the labels in the diagram:

[0030] 1. Mold; 2. Steel frame; 3. First embedded part; 4. Gel coat layer;

[0031] 11. First carbon fiber layer; 12. First glass fiber layer; 13. Thermally conductive diffusion layer; 14. Second carbon fiber layer; 15. Second glass fiber layer; 16. Thermal buffer layer. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] Example 1

[0034] This embodiment relates to a composite material molding die 1 with embedded parts. The die 1 is described in the state of composite material molding. "Closer to the molding surface" refers to the side of the die 1 that is in contact with the composite material product during the molding process, "away from the molding surface" refers to the side that is away from the composite material product, and "thickness direction of the die 1" refers to the direction from the molding surface to the back of the die 1.

[0035] Specifically, the composite material molding die 1 with pre-embedded parts is provided with one or more first pre-embedded parts 3. The die 1 includes a first pre-embedded part area with the first pre-embedded parts 3 and a non-pre-embedded part area without the first pre-embedded parts 3, wherein the first pre-embedded parts 3 are used to realize the positioning, assembly or connection and fixation of the die 1 with the corresponding second pre-embedded parts (not shown in the figure) in the molded product.

[0036] Furthermore, within the area of ​​the first embedded part, a gel coat layer 4, a first structural layer, a heat-conducting and diffusing layer 13, a second structural layer, and a heat buffer layer 16 are sequentially disposed along the thickness direction of the mold 1 from near the molding surface to away from the molding surface. The gel coat layer 4 is used to form the molding surface of the mold 1; the first structural layer is disposed on the side of the gel coat layer 4 away from the molding surface, and is used to provide basic structural strength for the mold 1; the heat-conducting and diffusing layer 13 is disposed between the first structural layer and the second structural layer; the second structural layer is disposed on the side of the heat-conducting and diffusing layer 13 away from the molding surface; the heat buffer layer 16 is compositely disposed on the outer surface of the second structural layer and covers the end of the first embedded part 3 away from the molding surface, so that the first embedded part 3 is not directly exposed to the external thermal environment on the back side of the mold 1.

[0037] Furthermore, in the non-embedded part area, only the gel coat layer 4, the first structural layer and the second structural layer are sequentially provided along the thickness direction of the mold 1 from near the molding surface to far away from the molding surface. In addition, the heat-conducting diffusion layer 13 and the heat buffer layer 16 are not provided in the non-embedded part area to maintain the continuity of the overall structure of the mold 1 and the manufacturing consistency.

[0038] Furthermore, a heat-conducting diffusion layer 13 is disposed between the first structural layer and the second structural layer, and is arranged circumferentially around the first embedded part 3 with the first embedded part 3 as the center. Through this arrangement, the heat generated and conducted by the first embedded part 3 during heating or curing can diffuse circumferentially to the surrounding area through the heat-conducting diffusion layer 13, thereby reducing the local temperature rise around the first embedded part 3.

[0039] Furthermore, the equivalent radius R1 of the heat-conducting diffusion layer 13 and the equivalent radius R2 of the first embedded part 3 satisfy R1≥1.5R2, so that the heat diffusion range covers a sufficiently large area around the first embedded part 3; the thickness of the heat-conducting diffusion layer 13 is 0.5~2.5mm, so as to ensure good thermal conductivity while taking into account the overall thickness and structural strength of the mold 1.

[0040] Furthermore, the heat-dissipating diffusion layer 13 is one of aluminum, copper, aluminum alloy, or copper alloy. In specific implementations, the heat-dissipating diffusion layer 13 can be made of industrial pure aluminum sheet, T2 copper sheet, or 6061 aluminum alloy sheet, which has stable thermal conductivity and is easy to laminate with composite materials. In this embodiment, the heat-dissipating diffusion layer 13 is a mesh-like T2 copper sheet with a thickness of 0.5 mm, and the equivalent radius R1 of the heat-dissipating diffusion layer 13 and the equivalent radius R2 of the first embedded part 3 are R1 = 4R2.

[0041] Furthermore, the thickness of the heat buffer layer 16 is 0.2–1.5 mm, used to isolate and slow down the release of heat from the first embedded part 3 and the heat-conducting diffusion layer 13. The heat buffer layer 16 is made of silicone-based thermal insulation material or ceramic fiber material. In specific implementations, the silicone-based thermal insulation material can be Bluestar high-temperature resistant silicone sheet, and the ceramic fiber material can be ceramic fiber sheet produced by Zhongke New Materials, both of which have low thermal conductivity, approximately 0.05–0.15 W / (m·K) and good heat resistance stability.

[0042] Furthermore, the first structural layer includes a first carbon fiber layer 11 and a first glass fiber layer 12, and the second structural layer includes a second carbon fiber layer 14 and a second glass fiber layer 15. The heat-conducting diffusion layer 13 is located between the first glass fiber layer 12 and the second carbon fiber layer 14. Through the above-mentioned interlayer arrangement, the fiber laying direction of the first carbon fiber layer 11 and the second carbon fiber layer 14 extends along the mold surface. This utilizes the excellent thermal conductivity of carbon fibers along the fiber direction, with a thermal conductivity of 5-20 W / (m·K), and up to 30 W / (m·K) when high-modulus carbon fibers are selected. This further assists the heat-conducting diffusion layer 13 in diffusing heat from the first embedded part 3, while reducing the temperature gradient along the vertical direction. The vertical thermal conductivity of carbon fibers is 0.3-1.0 W / (m·K).

[0043] In another embodiment, a molding method for a composite material molding die 1 with embedded parts is disclosed. The manufacturing method includes the following steps:

[0044] S1. Preparation of the male mold: Apply a release agent to the surface of the male mold (mold 1).

[0045] 1. Attach the nylon thread to the thread groove with all-purpose glue to prevent it from falling off. Do not let the glue overflow onto the mold surface. The nylon thread should extend above the mold surface.

[0046] 2. Clean the small engravings to remove debris such as dust and polishing wax, ensuring the surface of mold 1 is clean for the next process;

[0047] 3. Apply release agent 7-10 times, with a 30-minute interval between each application. The last application of release agent should be left to stand for 1 hour before proceeding with subsequent operations.

[0048] 4. Apply several coats of release agent to the corners to prevent sticking to the mold later;

[0049] 5. Apply two more coats of release agent to the areas where a demolding test is required to ensure a good demolding result.

[0050] S2. Place the first embedded part 3 according to the position shown in the design drawings, and attach the first embedded part 3 to the surface of the male mold 1:

[0051] 1. Place the first embedded part 3 precisely according to the location specified in the design drawings;

[0052] 2. Apply release wax to the positioning area during placement, ensuring that the outer side of the first embedded part 3 does not come into contact with the wax;

[0053] 3. For the first embedded part 3 with a smooth outer side, it should be roughened beforehand or a groove should be cut to prevent rotation or pull-out during use;

[0054] 4. Each first embedded part 3 is fixed to the surface of the male mold 1 with 502 glue to prevent loosening during the molding process and ensure that the first embedded part 3 remains in a fixed position.

[0055] S3. Spray gel coat layer 4 onto the surface of male mold 1:

[0056] The coating thickness should be controlled between 0.3mm and 0.4mm, with each coating layer being approximately 0.15mm thick and spaced 30 minutes apart. Thick coating should not be applied at corners to ensure that the gel coat layer 4 evenly covers the surface of the male mold 1, forming the molding surface of the mold 1.

[0057] S4. Prepare the first structural layer and lay the heat-conducting diffusion layer 13 in the first embedded part area:

[0058] S41. Lay the first carbon fiber layer 11 and the first glass fiber layer 12 in sequence, and lay the heat-conducting and diffusing layer 13 in the first embedded part area;

[0059] The material for the first structural layer is 30g / m³. 2 Carbon fiber surface mat, S-QXF 800g / m 2 Fiberglass cloth is then laid sequentially, with the first carbon fiber layer 11 and the first fiberglass layer 12 laid in strict accordance with the first laying record sheet. The laying width at corners is approximately 100mm, and the local width can be adjusted according to the actual situation. Bridging should not occur during the laying process. During the laying process, attention should be paid to the embedded parts to ensure that they are not loose. A heat-conducting and diffusing layer 13 is laid in the area of ​​the first embedded part, so that the heat-conducting and diffusing layer 13 is located between the first structural layer and the subsequent structural layers.

[0060] S42. Set up a vacuum system and check the vacuum level:

[0061] Lay out the release cloth, perforated release film, flow guide net, and resin tube in sequence; the distance from the flow guide net to the edge should be controlled at 80-100mm, and the reserved distance should be consistent throughout the circle; the flow guide tube should not contact the mold surface, and the laying of the flow guide tube must be strictly in accordance with the process instructions; the distance from the evacuation pipe to the layup area should be greater than 100mm, and bridging should not occur during the laying process; vacuum degree test requirements: close the valve and hold the pressure for 10 minutes, and the pressure drop should be less than 1.0KPa to ensure that the vacuum system is well sealed and to ensure the quality of resin impregnation.

[0062] S43. Introduce resin and perform the first curing, then remove the vacuum system and polish the contour of mold 1:

[0063] The resin used is EPMOLD155. After mixing the resin with the curing agent, it needs to be stirred for 3-5 minutes and then degassed for 5-10 minutes. When the indoor temperature is <15℃, the resin needs to be preheated and the resin temperature should be controlled at 25℃±5℃. The surface temperature of mold 1 needs to be greater than 18℃. If this temperature is not reached, mold 1 needs to be heated and maintained until the pouring is completed. During the pouring process, it is necessary to observe whether there is secondary air leakage until the resin gels. After the gel is completed, heating should be started and the temperature should be maintained >60℃ for 8 hours to complete the first curing. After curing, the vacuum system should be removed and the sharp corners of the mold 1 should be polished to be smooth.

[0064] S5. Prepare the second structural layer and lay the thermal buffer layer 16 in the area of ​​the first embedded part:

[0065] S51. The second carbon fiber layer 14 and the second glass fiber layer 15 are laid in sequence, and a heat buffer layer 16 is laid in the area of ​​the first embedded part, wherein the heat buffer layer 16 covers the end of the first embedded part 3 away from the forming surface.

[0066] The second structural layer is laid in the same way as the first structural layer, except for the corners. The second carbon fiber layer 14 and the second glass fiber layer 15 are laid in sequence. A heat buffer layer 16 is laid in the area of ​​the first embedded part, and the heat buffer layer 16 covers the end of the first embedded part 3 away from the molding surface. During the laying process, the surface temperature of the resin and the mold 1 is carried out in accordance with the molding process of the first structural layer.

[0067] S52. Set up a vacuum system and test the vacuum level. The testing standards are consistent with the vacuum level testing requirements in S42 to ensure the sealing effect.

[0068] S53. Introduce resin and perform a second curing:

[0069] The resin selected is EPMOLD155, and the relevant mixing, degassing and temperature control requirements are consistent with the resin introduction standard in S43. After the introduction is completed, a second curing is carried out, with a curing regime of >60℃ for 8 hours to complete the overall structure of mold 1. After curing, the steel frame 2 is connected: the steel frame 2 is positioned according to the height of the four corners, and then cured according to the curing regime of >60℃ for 8 hours.

[0070] S6. Subsequent processing:

[0071] 1. Demolding operation: Remove the first embedded part 3 from the surface of the male mold;

[0072] 2. Post-curing treatment: Starting from 60℃, increase the temperature by 10℃ per hour, and hold at 120℃ for 8 hours;

[0073] 3. Precision Inspection: Adjust the precision of mold 1 to meet the technical requirements and issue a 3D inspection report;

[0074] 4. Surface treatment: The surface must be free of pinholes, missing glue, and pits, and the scribing lines must be uniform and complete; grind the surface of mold 1 to P1000 to ensure there are no P800 sand marks, and then polish it; clean the residual polishing powder after polishing.

[0075] 5. Final inspection: Surface inspection, roughness inspection and vacuum inspection are completed, and roughness inspection report and vacuum inspection report are issued respectively. A certificate of conformity is issued after all indicators meet the standards.

[0076] Through the above structural design and manufacturing process, the heat of the first embedded part 3 is diffused by the heat-dissipating layer 13 combined with the excellent thermal conductivity of carbon fiber along the fiber direction. At the same time, combined with the heat insulation and slow release effect of the heat buffer layer 16, the temperature gradient in the area of ​​the first embedded part can be effectively reduced, the risk of local overheating can be reduced, and the thermal contact between the first embedded part 3 and the external environment can be reduced, so as to achieve uniform temperature distribution and structural stability of the mold 1 during the heating and curing process.

[0077] Comparative Example 1

[0078] The control mold produced in this comparative example only includes the gel coat layer 4, the first structural layer, and the second structural layer in the area of ​​the first embedded part 3. It does not have the heat-dissipating diffusion layer 13 and the heat buffer layer 16. The remaining materials, structural dimensions, and operating procedures are consistent with those of the embodiment. The first embedded part 3 is a titanium alloy component with a diameter of 10mm and a height of 15mm, and its fixing method is the same as in Embodiment 1.

[0079] Comparative Example 2

[0080] The control mold produced in this comparative example only includes a gel coat layer 4, a first structural layer, a thermally conductive and diffusing layer 13, and a second structural layer in the area of ​​the first embedded part 3, without a thermal buffer layer 16. The remaining materials, structural dimensions, and operating procedures are consistent with those of Example 1.

[0081] Comparative Example 3

[0082] In this comparative example, the control mold produced only includes the gel coat layer 4, the first structural layer, the heat buffer layer 16, and the second structural layer in the area of ​​the first embedded part 3. The remaining materials, heat-conducting and diffusion layer 13, structural dimensions, and operating procedures are consistent with those of Example 1.

[0083] Test case

[0084] To verify the effectiveness of the present invention, a comparative experiment was conducted using mold 1 with a thermally conductive diffusion layer 13 and a thermal buffer layer 16 from Example 1, and comparative molds 1-3. The specific operation was as follows: First, a second embedded part was placed in the prepared mold 1 according to the design drawings. The second embedded part was a titanium alloy component with a diameter of 8mm and a height of 10mm. Then, a molding operation was performed using the existing Vacuum Assisted Resin Transfer Molding (VARTM) process.

[0085] During the molding process, firstly, composite material dry cloth layers, including carbon fiber cloth and fiberglass cloth, are sequentially laid on the molding surface of mold 1, supplemented with a release film and a vacuum guide net to ensure that the composite material covers the entire molding area; then, a PE vacuum bag or a high-temperature composite material vacuum bag is covered, and the edges are sealed with sealing strips; a resin inlet, a vacuum extraction port, and an exhaust port are reserved on the vacuum bag, and a vacuum pump is connected to the resin storage tank; the vacuum pump is started to evacuate the inside of mold 1, so that the layup adheres tightly to the surface of mold 1, while maintaining the vacuum degree at 0.08-0.09 MPa; under vacuum, the pre-mixed epoxy resin EPMOLD155 is introduced into the layup from the inlet to ensure uniform resin penetration; under vacuum, mold 1 is heated to 60-80℃ for curing, and the curing time is 8-12 hours; after curing, it is slowly cooled to room temperature, the vacuum is released, the vacuum bag and release film are removed, and the molded part is demolded.

[0086] The formed parts were inspected using a coordinate measuring machine (CMM) to measure critical dimensions, including the location, thickness, and overall contour of the second embedded part holes. Measurement data were recorded, and the average dimensional deviation from multiple forming cycles (20 cycles) was calculated. Simultaneously, the presence of warping, cracking, or microcracks was observed in the formed parts. The inspection results are as follows:

[0087] Mold type Average deviation of critical dimensions of molded parts (mm) Maximum deviation (mm) Minimum deviation (mm) Warping / Cracking Remark Example 1 0.12 0.18 0.08 none With thermally conductive diffusion layer and thermal buffer layer Comparative Example 1 0.35 0.50 0.25 Slight warping, minor cracking No thermal diffusion layer or thermal buffer layer was installed. Comparative Example 2 0.22 0.30 0.15 No obvious warping, no cracking Only a heat-conducting diffusion layer is provided; no heat buffer layer is provided. Comparative Example 3 0.28 0.40 0.20 Slight warping, no cracks Only a thermal buffer layer is provided; no thermal diffusion layer is provided.

[0088] Conclusion Analysis:

[0089] 1. The mold of Example 1, namely the mold 1 with both a heat-dissipating diffusion layer 13 and a heat buffer layer 16, exhibits the lowest average deviation in critical dimensions of its molded parts, at 0.12 mm. The maximum and minimum deviations are 0.18 mm and 0.08 mm, respectively, and no warping, cracking, or microcracks were observed. This indicates that simultaneously introducing the heat-dissipating diffusion layer 13 and the heat buffer layer 16 into the area of ​​the first embedded part 3 can synergistically regulate heat conduction and slow release, effectively reducing the local temperature gradient. This significantly improves the dimensional control capability and structural stability of the mold 1 during thermal cycling, ensuring a high degree of consistency in the overall shape and hole positions of the molded parts.

[0090] 2. Comparative Example 2 mold, which only has a heat-dissipating diffusion layer 13 and no heat buffer layer 16, has an average dimensional deviation of 0.22 mm, a maximum deviation of 0.30 mm, and a minimum deviation of 0.15 mm. No obvious warping or cracking was observed. Compared with Example 1, although the lack of heat buffer layer 16 results in a slightly larger temperature gradient in the thickness direction, the heat-dissipating diffusion layer 13 can effectively diffuse the local heat of the first embedded part 3 laterally along the mold 1, making the heat distribution more uniform. This significantly improves dimensional accuracy and structural consistency, verifying the core role of the heat-dissipating diffusion layer 13 in controlling heat concentration around the first embedded part 3 and reducing local thermal stress.

[0091] 3. Comparative Example 3 mold, with only a heat buffer layer 16 and no heat-conducting diffusion layer 13, showed an average deviation of 0.28 mm, a maximum deviation of 0.40 mm, and a minimum deviation of 0.20 mm for the molded parts. Slight warping occurred, but no cracking was observed. The results of Comparative Example 3 show that the heat buffer layer 16 can mitigate the heat transferred from the first embedded part 3 to the outside of the mold 1, reduce the temperature gradient in the thickness direction, and reduce local thermal stress concentration, thereby improving the warping and cracking of the molded parts. However, due to the lack of heat diffusion effect of the heat-conducting diffusion layer 13 in the plane direction of the mold 1, some local heat concentration still exists, resulting in a dimensional deviation that is still significantly greater than that of Example 1 and Comparative Example 2.

[0092] 4. In Comparative Example 1, without the thermal diffusion layer 13 and the thermal buffer layer 16, the average deviation of the molded parts was 0.35 mm, the maximum deviation was 0.50 mm, and the minimum deviation was 0.25 mm. Slight warping and a small number of cracks were also observed. The results of Comparative Example 1 further confirm that when the area of ​​the first embedded part 3 lacks a thermal management structure, local heat cannot be effectively diffused and released, resulting in significant local overheating and temperature gradients. This leads to increased dimensional deviations and structural defects in the molded parts, verifying the crucial role of the thermal management layer in improving the molding accuracy and structural reliability of mold 1.

[0093] Based on the above four sets of data, it can be seen that the synergistic design of the heat-conducting diffusion layer 13 and the heat buffer layer 16 in the area of ​​the first embedded part 3 has a significant effect on controlling the thermal field distribution of the mold 1, reducing local stress, and improving the dimensional accuracy and structural consistency of the molded part. Among them, the heat-conducting diffusion layer 13 mainly acts on the transverse heat diffusion and improves the thermal balance, while the heat buffer layer 16 mainly acts on the heat release and isolation in the thickness direction. The two complement each other, enabling Example 1 to exhibit the best dimensional accuracy, the smallest deviation, and the most stable structural performance in multiple molding cycles.

[0094] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0095] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0096] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0097] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite material molding die with embedded parts, characterized in that: The mold is provided with one or more first embedded parts. The mold includes a first embedded part area with the first embedded parts and a non-embedded part area without the first embedded parts. The first embedded part area includes, in sequence along the thickness direction of the mold from near the forming surface to away from the forming surface: a gel coat layer, a first structural layer, a heat-conducting and diffusing layer, a second structural layer, and a heat buffer layer. The heat buffer layer is compositely disposed on the outer surface of the second structural layer and covers the end of the first embedded part away from the forming surface. The non-embedded part area, along the thickness direction of the mold, includes, in sequence from the area closest to the molding surface to the area furthest from the molding surface: a gel coat layer, a first structural layer, and a second structural layer; The heat-conducting and diffusion layer is disposed between the first structural layer and the second structural layer and is arranged along the circumference of the first embedded part to diffuse the heat generated by the first embedded part to the surrounding area.

2. The composite material molding die with embedded parts according to claim 1, characterized in that: The thickness of the thermally conductive diffusion layer is 0.5~2.5mm.

3. The composite material molding die with embedded parts according to claim 1, characterized in that: The thermally conductive diffusion layer is one of aluminum, copper, aluminum alloy, or copper alloy.

4. A composite material molding die with embedded parts according to claim 1, characterized in that: The thickness of the heat buffer layer is 0.2 to 1.5 mm.

5. A composite material molding die with embedded parts according to claim 4, characterized in that: The heat buffer layer is made of silicone-based heat insulation material or ceramic fiber material.

6. A composite material molding die with embedded parts according to claim 1, characterized in that: The first structural layer includes a first carbon fiber layer and a first glass fiber layer, the second structural layer includes a second carbon fiber layer and a second glass fiber layer, and the thermally conductive diffusion layer is located between the first glass fiber layer and the second carbon fiber layer.

7. A method for manufacturing a composite material molding die with embedded parts as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Prepare the male mold by applying a release agent to the surface of the male mold. S2. Place the first embedded part according to the position in the design drawings, and attach the first embedded part to the surface of the male mold. S3. Spray a gel coat layer onto the surface of the male mold. S4. Prepare the first structural layer and lay a heat-conducting and diffusing layer in the first embedded part area; S5. Prepare the second structural layer and lay a thermal buffer layer in the area of ​​the first embedded part.

8. The method for manufacturing a composite material molding die with embedded parts according to claim 7, characterized in that: Step S4 specifically includes: S41. Lay the first carbon fiber layer and the first glass fiber layer in sequence, and lay the heat-conducting and diffusing layer in the first embedded part area; S42. Set up a vacuum system and test the vacuum level; S43. Import the resin and perform the first curing, then remove the vacuum system and polish the mold outline.

9. The method for manufacturing a composite material molding die with embedded parts according to claim 7, characterized in that: Step S5 specifically includes: S51. Lay the second carbon fiber layer and the second glass fiber layer in sequence, and lay a heat buffer layer in the area of ​​the first embedded part, the heat buffer layer covering the end of the first embedded part away from the forming surface. S52. Set up a vacuum system and test the vacuum level; S53. Introduce resin and perform a second curing.

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