Molding molds and methods for carbon fiber composite materials

Abstract

The present invention discloses a carbon fiber composite molding die and a method thereof, the die includes a curing die and a preform shell mold which can be detachably joined together, the curing die is provided with a curing cavity for receiving the preform shell mold, the preform shell mold is provided with a preform cavity conforming to the structure of the molding product, the inner wall of the preform cavity is laid with a number of carbon fiber composite preform layers to form the preform of the product, a nylon duct is provided in the preform cavity, and the nylon duct supports the preform layer to be in close contact with the inner wall of the preform cavity when filled with air. The present invention provides a carbon fiber composite molding die and a method thereof, which lays layers from the outside to the inside, directly reinforcing the local areas that need internal reinforcement, ensuring the overall strength of the molding product, and making the product surface smooth and flat, thereby eliminating the subsequent surface smoothing process after molding of the product, and saving labor costs.

Description

Technical Field

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[0001] The present invention relates to the technical field of carbon fiber, and more specifically to a mold and a method for forming a carbon fiber composite material.

Background Art

[0002] Carbon fiber composite materials have the advantages of weight reduction and high strength, and are widely applied. Especially in the field of high-end bicycles, with the improvement of people's living standards, the demand for high-end bicycles has increased, bicycle sports have become popular, and there is a growing demand for lighter cycling tools. Due to its light weight and strength characteristics, carbon fiber is optimal for manufacturing lightweight bicycles.

[0003] In the prior art, when carbon fiber composite materials are commercialized, usually, a carbon fiber yarn layer is laid in the curing cavity of the metal mold cavity, and then cured and formed with a high-temperature heating mold. However, such a process of this method is complicated, inefficient, cannot be demolded without using a mold release agent, and there are residues (extra resin) in the metal mold after demolding. Moreover, due to different demands on the structure of the curing cavity of the metal mold by product parts, it is necessary to open multiple metal molds, resulting in high costs.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a mold and a method for forming a carbon fiber composite material to solve the above problems.

Means for Solving the Problems

[0007] Preferably, the preformed shell mold includes several sets of separable shell molds that are joined together.

[0008] Preferably, two adjacent sets of the separable shell molds are detachably joined together by an engaging structure.

[0009] Preferably, the curing mold includes an upper curing mold and a lower curing mold, the upper curing mold being installed to be vertically movable directly above the lower curing mold, an upper curing groove provided on the bottom side of the upper curing mold, and a lower curing groove provided on the top side of the lower curing mold, the upper curing groove and the lower curing groove fitting together to form a curing cavity for housing the preform shell mold.

[0010] Preferably, the preform layer includes several layers and is made of carbon fiber composite material.

[0011] Preferably, the hardening mold is made of metal.

[0012] Preferably, the preform shell mold is made of plastic material.

[0013] A method for molding carbon fiber composite material, comprising: step S1 precasting several sets of separable shell molds and laying carbon fiber composite material inside the separable shell molds to form a preform layer; step S2 joining the several sets of separable shell molds to form a preform shell mold and tightly fitting the preform layers inside each set of separable shell molds to form a product preform, and pre-inserting a nylon duct inside the preform; and filling the nylon duct with air and holding the pressure for several seconds to expand the nylon duct and expand the preform layer. Step S3 includes supporting the reform shell mold so that it is in close contact with the inner wall of the preform cavity; step S4 includes leaving the preform shell mold in the curing cavity of the curing mold, heating the curing mold and simultaneously pressurizing the nylon duct, performing the heating and pressurizing processes simultaneously, continuing until the temperature and pressure reach the requirements for curing, and continuing the holding pressure until the preform is completely molded and cured to form the first product; and step S5 includes opening the curing mold, peeling the preform shell mold from the surface of the first product, removing the first product, and obtaining the finished product after machining and surface treatment.

[0014] By employing the above technical solution, the present invention has the following advantages compared to the background art.

[0015] 1. The present invention provides a molding die and method for carbon fiber composite materials. First, a preform layer of carbon fiber composite material is laid inside each separate shell mold. Then, the separate shell molds are joined together to form a preform shell mold. Subsequently, the preform shell mold is placed in a curing die and curing is performed. The preform cavity structure of the preform shell mold conforms to the structure of the product to be formed. When laying the carbon fiber composite material, the layers are laid in layers from the outside to the inside, directly reinforcing localized areas where internal reinforcement is needed, ensuring the overall strength of the molded product. Furthermore, by making the product surface smooth and flat, the subsequent post-molding surface smoothing process of the product can be eliminated, saving labor costs.

[0016] 2. In the carbon fiber composite material molding die and method of the present invention, demolding is easy, the preform shell mold can be removed without the need for a release agent, the plastic preform shell mold can be directly peeled off from the cured product, there is no residue in the cured die, it can be used continuously, there is no need to clean the die even after long-term use, it is easy to operate, it is less likely to damage the product, the production process is simplified compared to conventional processes, the process time is shortened, and the production costs of companies are reduced.

[0017] 3. The present invention provides a mold and method for molding carbon fiber composite materials, which allows for adjustment of the preform cavity structure of the preform shell mold according to the demands of the actual product structure, and a general-purpose mold can be used as the curing mold. Compared to the structure of a curing mold in which metal materials are adjusted, the cost and difficulty of the plastic material preform shell mold are both lower, resulting in reduced production costs for companies. [Brief explanation of the drawing]

[0018] [Figure 1] This is a flowchart of the molding process of the present invention. [Figure 2] This is a schematic diagram of the structure of the molding die of the present invention. [Figure 3] This is a schematic diagram of the structure of the preform shell mold of the present invention. [Modes for carrying out the invention]

[0019] To further clarify the object, technical solution, and advantages of the present invention, the present invention will be described in more detail below, with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are for interpretation purposes only and not to limit the present invention.

[0020] Examples As shown in FIGS. 1 to 3, the present invention discloses a molding die for a carbon fiber composite material. The products formed from the carbon fiber composite material in this embodiment include, but are not limited to, bicycle rims, bicycle frames, bicycle handlebars, etc. In this embodiment, specifically, a bicycle rim is taken as an example. The molding die includes a curing die 1 and a preform shell mold 2 that is detachably joined. The curing die 1 is provided with a curing cavity 11 for accommodating the preform shell mold 2. The preform shell mold 2 is provided with a preform cavity 21 that conforms to the structure of the molded product. On the inner wall of the preform cavity 21, several layers of preform layers 3 of carbon fiber composite material for forming the preform of the product are laid. A nylon duct 4 is provided in the preform cavity 21, and the nylon duct 4 supports the preform layer 3 to be in close contact with the inner wall of the preform cavity 21 in a state filled with air.

[0021] The preform shell mold 2 includes several sets of split shell molds that are joined. Two adjacent sets of split shell molds are detachably joined by an engaging structure. The engaging structure includes a fastener and a locking port. By inserting the fastener into the locking port and locking and fixing it, two adjacent sets of split shell molds are fixed and joined.

[0022] The curing die 1 includes an upper curing die 12 and a lower curing die 13. The upper curing die 12 is installed above the lower curing die 13 so as to be able to move up and down. An upper curing groove is provided on the bottom side of the upper curing die 12, and a lower curing groove is provided on the top side of the lower curing die 13. The upper curing groove and the lower curing groove are fitted to form a curing cavity 11 for accommodating the preform shell mold 2.

[0023] The preform layer 3 includes several layers and adopts a carbon fiber composite material. The number of layers of the preform layer 3 at different positions can be adjusted according to actual needs. For example, more layers can be laid and reinforced at local sites that require reinforcement.

[0024] The hardened mold 1 is made of a metal material, and the preform shell mold 2 is made of a plastic material.

[0025] The present invention further discloses a method for forming a carbon fiber composite material, including step S1 of precasting several sets of split shell molds, laying a carbon fiber composite material inside the split shell molds to form a preform layer 3; step S2 of joining several sets of split shell molds together to form a preform shell mold 2, and closely fitting the preform layers 3 inside each set of split shell molds to form a preform of the product, and pre-inserting a nylon duct 4 into the preform; step S3 of filling air into the nylon duct 4, maintaining pressure for several seconds to expand the nylon duct 4, and supporting the preform layer to adhere to the inner wall of the preform cavity 21 of the preform shell mold 2; step S4 of placing the preform shell mold 2 in the curing cavity 11 of the hardened mold 1, heating the hardened mold 1, and pressurizing the nylon duct 4 at the same time, simultaneously performing the heating process and the pressurizing process, continuing until the temperature and pressure reach the requirements of curing and forming, and continuing the pressure holding until the preform is completely formed and cured to form a primary product; step S5 of opening the hardened mold 1, peeling the preform shell mold 2 from the surface of the primary product, taking out the primary product, and obtaining a finished product after machining and surface treatment.

[0026] In this embodiment, the molded product is specifically exemplified by a bicycle rim. The split shell mold 2 includes three sets: an upper shell mold 22, a lower shell mold 23, and an outer rim shell mold 24. A first fastener is provided inside the upper shell mold 22, a first locking port adapted to the first fastener is provided inside the lower shell mold 23, second locking ports are provided on the outer sides of both the upper shell mold 22 and the lower shell mold 23, second fasteners adapted to the second locking ports are provided at both ends of the outer rim shell mold 24, and the preform layer 3 includes four sets: an upper preform layer, a lower preform layer, an outer rim preform layer, and an inner rim preform layer. The specific forming method includes the following steps.

[0027] 1) The upper shell mold 22, lower shell mold 23, and outer rim shell mold 24 are precast, and the upper preform layer, lower preform layer, and outer rim preform layer are laid inside the upper shell mold, lower shell mold, and outer rim shell mold 13, respectively.

[0028] 2) The outer rim shell mold 24 and the inner rim preform layer are placed on both inner ends of the lower shell mold 23 and joined together, and a nylon duct is inserted between the outer rim shell mold 24, the inner rim preform layer and the lower shell mold 23.

[0029] 3) The inner rim preform layer is laid in advance using an external preform jig and formed. The laid and formed inner rim preform layer is then placed on the lower shell mold 23 and assembled. The upper shell mold 22, lower shell mold 23, and outer rim shell mold 24 are joined together to form a preform shell mold 2. The upper preform layer, lower preform layer, outer rim preform layer, and inner rim preform layer are then tightly fitted together to form a rim preform.

[0030] Here, the upper and lower preform layers become thinner closer to the inner rim preform layer during the laying process, facilitating flat adhesion between the inner rim preform layer and the upper and lower preform layers. The outer rim preform layer extends to both sides during the laying process, facilitating flat adhesion between the outer rim preform layer and the upper and lower preform layers, ensuring the strength of the joints of the rim after molding. At the same time, during the laying process of the preform layers, thicker layers are laid in localized areas, such as brake areas and spoke hole areas, to provide localized reinforcement.

[0031] The preform shell mold 2 is further provided with mounting holes (not shown) that penetrate the inside and outside of the preform shell mold for attaching a tire air valve member, and the end of the nylon duct 3 is pulled out through the mounting holes and connected to the air valve member.

[0032] 4) The air valve component is used to fill the nylon duct 4 with air, hold the pressure for several seconds, and inflate the nylon duct to support the preform layer so that it adheres tightly to the inner wall of the preform cavity of the preform shell mold.

[0033] 5) Place the preform shell mold 2 inside the curing cavity 11 of the curing mold 1, heat the curing mold 1, and simultaneously pressurize the nylon duct 4. Continue the heating and pressurizing processes simultaneously, maintaining the temperature and pressure at 145°C to 155°C and 1.5 MPa to 1.8 MPa, until the rim preform is completely molded and cured, forming the rim.

[0034] 6) The hardening mold 1 is opened, the preform shell mold 2 is peeled off the surface of the rim, the rim is removed, and after machining and surface treatment, the finished rim is obtained.

[0035] The above description represents only preferred specific embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any modification or substitution that a person skilled in the art can easily conceive of within the technical scope presented herein should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A molding die for a carbon fiber composite material, comprising a curing die and a detachably joined preform shell mold, wherein the curing die is provided with a curing cavity for housing the preform shell mold, the preform shell mold is provided with a preform cavity conforming to the structure of the molded product, a nylon duct is provided within the preform cavity, and the nylon duct, when filled with air, supports a preform layer for forming the preform of the product to be laid on the inner wall of the preform cavity so as to be in close contact with the inner wall of the preform cavity.

2. The preformed shell mold is characterized by including several sets of separable shell molds that are joined together. A mold for molding a carbon fiber composite material according to claim 1.

3. The two adjacent sets of the aforementioned separable shell molds are characterized by being detachably joined together by an engaging structure. A mold for molding a carbon fiber composite material according to claim 2.

4. The curing mold comprises an upper curing mold and a lower curing mold, wherein the upper curing mold is installed so as to be vertically movable directly above the lower curing mold, an upper curing groove is provided on the bottom side of the upper curing mold, and a lower curing groove is provided on the top side of the lower curing mold, and the upper curing groove and the lower curing groove fit together to form a curing cavity for housing the preform shell mold. A mold for molding a carbon fiber composite material according to claim 1.

5. The aforementioned preform layer is characterized by containing several layers and employing a carbon fiber composite material. A mold for molding a carbon fiber composite material according to claim 1.

6. The hardening mold is characterized by employing a metal material. A mold for molding a carbon fiber composite material according to claim 1.

7. The aforementioned preform shell mold is characterized by employing a plastic material. A mold for molding a carbon fiber composite material according to claim 1.

8. A method for molding a carbon fiber composite material using a molding die according to any one of claims 1 to 7, Step S1 involves precasting several sets of separable shell molds and laying a carbon fiber composite material inside the separable shell molds to form a preform layer. Step S2 involves joining several sets of the aforementioned separable shell molds to form a preform shell mold, and tightly fitting the preform layers inside each set of the aforementioned separable shell molds to form a product preform, and pre-inserting a nylon duct into the inside of the preform, Step S3 involves filling the nylon duct with air and holding the pressure for several seconds to expand the nylon duct and support the preform layer so that it adheres tightly to the inner wall of the preform cavity of the preform shell mold. Step S4 involves placing the preform shell mold in the curing cavity of the curing mold, heating the curing mold, and simultaneously pressurizing the nylon duct, performing the heating and pressurizing processes simultaneously, continuing until the temperature and pressure reach the requirements for curing, and continuing the holding pressure until the preform is completely molded and cured, thereby forming the first product. A molding method characterized by including step S5: opening the hardening mold, peeling the preform shell mold from the surface of the initial product, removing the initial product, and obtaining a finished product after machining.

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