High-thermal-conductivity composite die

Abstract

The utility model discloses a composite die with high thermal conductivity, which comprises an upper die and a lower die, the upper die comprises an upper die main body and an upper die structure frame body arranged in the circumferential direction of the outer side of the upper die main body, and the upper die main body comprises an upper die graphite layer and a metal layer; the lower die comprises a lower die main body and a lower die structure frame body arranged in the circumferential direction of the outer side of the lower die main body, and the lower die main body comprises a lower die graphite layer and a lower die metal layer. And the production efficiency can be greatly improved when the mold is applied to thermoplastic composite material mold pressing.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic composite material preparation, and more specifically to a high thermal conductivity composite mold. Background Technology

[0002] Thermoplastic composites have gradually become known to the public due to their unique advantages such as high impact resistance, recyclability, resistance to corrosion from various organic solvents, and low specific gravity.

[0003] Currently, the molding technology for thermoplastic prepreg products is relatively immature, with fewer processes available, primarily compression molding. Compared to compression molding of thermosetting prepreg products, thermoplastic compression molding places higher demands on the molds. The curing temperature of conventional thermosetting prepreg products is around 150℃, while the curing temperature of thermoplastic prepreg products is much higher. For example, PP cures at around 160-200℃, PA6 at 240-260℃, and PEEK at 400℃+. Furthermore, because thermoplastic resins have a higher viscosity than thermosetting resins, higher molding pressure is required to achieve better molding results. Therefore, the compression molding process for thermoplastic prepreg products places high demands on the molds.

[0004] In the prior art, the molds used for molding processes are mainly: (1) alloy steel molds, which have good durability, but are heavy, costly, have low heating performance, uneven temperature distribution, and are prone to stress; (2) aluminum alloy molds have low density, good compactness, and good thermal conductivity, which makes aluminum alloys heat up quickly and can be better heated and formed in component manufacturing, but their expansion coefficient is too different from that of composite materials, causing the composite materials to deform; (3) composite material molds and products have good matching thermal expansion coefficients, low density, and good dimensional thermal stability, but the mold manufacturing process is complicated, the processing cost is high, and the service life is short.

[0005] Graphite has a thermal expansion coefficient close to that of composite materials and high thermal conductivity. However, its brittleness and high porosity limit its application in composite material molding. Table 1 compares the performance of graphite molds with existing mold technologies.

[0006] Table 1

[0007] <![CDATA[Coefficient of thermal expansion (×10 -6 × °C -1 )]]> <![CDATA[Thermal conductivity (×10 -6 ×°C -1 ).]]> <![CDATA[Density (Kg·m -3 )]]> Low carbon steel mold 12.1 30-40 7.8 Aluminum alloy mold 24 130-150 2.8 Composite material mold (carbon fiber) 3.6 0.3-20 1.5 Graphite mold 4.75 120-130 1.85 Summary of the Invention

[0008] The purpose of this invention is to provide a high thermal conductivity composite graphite mold that can solve the problems encountered by alloy steel molds, aluminum alloy molds, and composite material molds in the molding process of thermoplastic prepreg products.

[0009] To achieve the above objectives, the present invention provides a high thermal conductivity composite mold, specifically including an upper mold and a lower mold, wherein the upper mold and the lower mold, when fitted together, form a product cavity; the upper mold includes an upper mold body and an upper mold structural frame, the upper mold structural frame being disposed on the outer circumferential side of the upper mold body and tightly fitted therewith; the upper mold body includes an upper mold graphite layer; the lower mold includes a lower mold body and a lower mold structural frame, the lower mold structural frame being disposed on the outer circumferential side of the lower mold body and tightly fitted therewith; the lower mold body includes a lower mold graphite layer.

[0010] In another embodiment, the upper mold body further includes a thin upper mold metal layer or an upper mold metal film layer disposed on the bottom surface of the graphite layer; the lower mold body further includes a thin lower mold metal layer or a lower mold metal film layer disposed on the top surface of the lower mold graphite layer, and after the upper mold and the lower mold are closed, a product cavity is formed between the upper mold metal layer and the lower mold metal layer.

[0011] The upper and lower mold metal layers are made of dense, airtight metal materials that do not affect the composite K-value. Preferably, the upper mold metal layer is an upper mold forming aluminum surface or an upper mold forming steel surface, and the lower mold metal layer is a lower mold forming aluminum surface or a lower mold forming steel surface.

[0012] In another embodiment, thermally conductive buffer layers are provided between the upper mold graphite layer and the upper mold structural frame, and between the lower mold graphite layer and the lower mold structural frame. The thermally conductive buffer layers are structural adhesives containing Al or Ag ions.

[0013] In another embodiment, the upper mold structure frame includes a first upper mold structure frame and a second upper mold structure frame, the second upper mold structure frame being disposed below the first upper mold structure frame, and the outer dimensions of the first upper mold structure frame being larger than the outer dimensions of the second upper mold structure frame; the lower mold structure frame includes a first lower mold structure frame and a second lower mold structure frame, the second lower mold structure frame being disposed above the first lower mold structure frame, and the outer dimensions of the first lower mold structure frame being larger than the outer dimensions of the second lower mold structure frame.

[0014] In another embodiment, the upper mold frame and the lower mold frame are made of aluminum alloy.

[0015] In another embodiment, the upper mold forming aluminum surface or the upper mold forming steel surface is in close contact with the upper mold graphite layer and is connected and fixed to the second upper mold structural frame by bolts; the lower mold forming aluminum surface or the lower mold forming steel surface is in close contact with the lower mold graphite layer and is fixed by the second lower mold structural frame.

[0016] In another embodiment, a groove is provided on the bottom surface of the graphite layer lower mold body, and ribs are provided on the first lower mold structure frame, the ribs cooperating with the groove.

[0017] In another embodiment, the high thermal conductivity composite mold further includes a mold closing guide block and a positioning groove that cooperate with each other. The mold closing guide block is disposed on the upper mold structure frame, specifically on the second upper mold structure frame; the positioning groove is disposed on the lower mold structure frame, specifically on the second lower mold structure frame.

[0018] Advantages of this invention:

[0019] Compared with existing technologies, graphite's high thermal conductivity enables rapid heating and cooling, reducing the molding time from 45 minutes to 15 minutes when processing thermoplastic carbon fiber composites, thus significantly improving molding efficiency.

[0020] A structural frame is set around the graphite layers of the upper and lower molds, and a heat-conducting buffer layer is also set between the graphite layers and the structural frame to prevent the graphite from cracking during the molding process and to improve the service life of the graphite mold.

[0021] In addition, a thin, dense, and airtight metal layer is placed on the graphite layer, which can ensure the heating rate of the mold while preventing resin from penetrating into the gaps in the graphite layer, thus improving the service life of the graphite mold. Attached Figure Description

[0022] Appendix Figure 1 This is a schematic diagram of a high thermal conductivity composite mold structure;

[0023] Appendix Figure 2 This is a cross-sectional view of a high thermal conductivity mold in its open state.

[0024] Appendix Figure 3 Temperature rise curves for high thermal conductivity composite mold and P20 mold;

[0025] Wherein: 1-Upper mold; 11-Upper mold body; 111-Upper mold graphite layer; 112-Upper mold forming aluminum surface; 12-Upper mold structural frame; 121-First upper mold structural frame; 122-Second upper mold structural frame; 2-Lower mold; 21-Lower mold body; 211-Lower mold graphite layer; 212-Lower mold forming aluminum surface; 22-Lower mold structural frame; 221-First lower mold structural frame; 222-Second lower mold structural frame; 3-Heat-conducting buffer layer; 4-Mold closing guide block. Detailed Implementation

[0026] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "inner," and "outer," etc., 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 utility model and simplifying the description, and do not 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 utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] Combined with appendix Figure 1-2 A high thermal conductivity composite mold includes an upper mold 1 and a lower mold 2, which, when mated, form a cavity. The upper mold 1 includes an upper mold body 11 and an upper mold structural frame 12 disposed on the outer circumferential direction of the upper mold body 11. The upper mold body 11 includes an upper mold graphite layer 111. The lower mold 2 includes a lower mold body 21 and a lower mold structural frame 22 disposed on the outer circumferential direction of the lower mold body 21, the lower mold body 21 including a lower mold graphite layer 211. The upper mold structural frame 12 and the lower mold structural frame 22 are made of aluminum alloy.

[0030] Combined with appendix Figure 2The upper mold body 11 also includes an upper mold forming aluminum surface 112, which is disposed on the bottom surface of the upper mold graphite layer 111; the lower mold body 21 also includes a lower mold forming aluminum surface 212, which is disposed on the top surface of the lower mold graphite layer 211; after the upper mold 1 and the lower mold 2 are closed, a product cavity is formed between the upper mold forming aluminum surface 112 and the lower mold forming aluminum surface 212. A thermally conductive buffer layer 3, specifically Ag ion structural adhesive, is provided between the upper mold graphite layer 111 and the upper mold structural frame 12 and between the lower mold graphite layer 211 and the lower mold structural frame 22. The upper mold frame 12 includes a first upper mold frame 121 and a second upper mold frame 122. The second upper mold frame 122 is located below the first upper mold frame 121 and the two are fixed together by bolts. The outer dimensions of the first upper mold frame 121 are larger than the outer dimensions of the second upper mold frame 122. The lower mold frame 22 includes a first lower mold frame 221 and a second lower mold frame 222. The second lower mold frame 222 is located above the first lower mold frame 221 and the two are fixed together by bolts. The outer dimensions of the first lower mold frame 221 are larger than the outer dimensions of the second lower mold frame 222. The upper mold forming aluminum surface 112 is fixed to the second upper mold frame 122 by bolts. The lower mold forming aluminum surface 212 is limited and fixed to the top surface of the lower mold graphite layer 211 by the second lower mold frame 222. The lower bottom surface of the graphite layer 211 of the lower mold is provided with a groove, and the first lower mold structural frame 221 is provided with ribs, which cooperate with the groove. The upper mold structural frame 12 is also provided with a mold closing guide block 4, and the lower mold structural frame 22 is provided with a positioning groove that cooperates with the mold closing guide block 3.

[0031] See appendix Figure 3 The figure shows the heating curves of the high thermal conductivity composite mold and the P20 mold in this embodiment. It can be seen that the heating rate of the high thermal conductivity composite mold is faster than that of the P20. When the temperature reaches 200°C, the high thermal conductivity composite mold takes about 24 minutes, while the P20 takes 34 minutes.

[0032] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model. As described in the above embodiments of this utility model, other structures obtained by using the same or similar structures are all within the protection scope of this utility model.

Claims

1. A high thermal conductivity composite mold, comprising an upper mold and a lower mold, wherein the upper mold and the lower mold, when fitted together, form a cavity; characterized in that, The upper mold includes an upper mold body and an upper mold structural frame disposed on its outer circumferential direction, the upper mold body including an upper mold graphite layer; the lower mold includes a lower mold body and a lower mold structural frame disposed on its outer circumferential direction, the lower mold body including a lower mold graphite layer.

2. The high thermal conductivity composite mold according to claim 1, characterized in that, The upper mold body also includes an upper mold metal layer disposed on the bottom surface of the upper mold graphite layer, and the lower mold body also includes a lower mold metal layer disposed on the top surface of the lower mold graphite layer; after the upper mold and lower mold are closed, a product cavity is formed between the upper mold metal layer and the lower mold metal layer.

3. The high thermal conductivity composite mold according to claim 2, characterized in that, The upper mold metal layer is specifically an upper mold formed aluminum surface or an upper mold formed steel surface, and the lower mold metal layer is specifically a lower mold formed aluminum surface or a lower mold formed steel surface.

4. The high thermal conductivity composite mold according to claim 1, characterized in that, A thermally conductive buffer layer is also provided between the upper mold graphite layer and the upper mold structural frame, and between the lower mold graphite layer and the lower mold structural frame.

5. A high thermal conductivity composite mold according to claim 2, characterized in that, The upper mold structure frame includes a first upper mold structure frame and a second upper mold structure frame. The second upper mold structure frame is located below the first upper mold structure frame, and the outer dimensions of the first upper mold structure frame are larger than the outer dimensions of the second upper mold structure frame. The lower mold structure frame includes a first lower mold structure frame and a second lower mold structure frame. The second lower mold structure frame is located above the first lower mold structure frame, and the outer dimensions of the first lower mold structure frame are larger than the outer dimensions of the second lower mold structure frame.

6. A high thermal conductivity composite mold according to claim 5, characterized in that, The upper mold frame and the lower mold frame are made of aluminum alloy or steel.

7. The high thermal conductivity composite mold according to claim 3, characterized in that, The upper mold forming aluminum surface or upper mold forming steel surface is closely attached to the upper mold graphite layer and connected to the second upper mold structural frame by bolts; the lower mold forming aluminum surface or lower mold forming steel surface is closely attached to the lower mold graphite layer and fixed by the second lower mold structural frame.

8. The high thermal conductivity composite mold according to claim 5, characterized in that, The bottom surface of the graphite layer of the lower mold is provided with a groove, and the first lower mold structure frame is provided with ribs, which cooperate with the groove.

9. The high thermal conductivity composite mold according to claim 1, characterized in that, It also includes a mold closing guide block, which is disposed on the upper mold structure frame; the lower mold structure frame is provided with a positioning groove to cooperate with the guide block.

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