Flexible mold for forming composite material shell by thermal diaphragm process
By using silicone edge film and rubber base film with a reserved expansion fusion gap in the thermal isolation process, combining thermal expansion and vulcanization technology to form flexible molds with specific forms, the poor quality and flexibility of composite material molding surfaces in the thermal isolation process are solved. The problem of high mold cost achieves efficient molding effect and cost reduction.
Patent Information
- Application Number
- CN202411500040.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2024-12-27
AI Technical Summary
When forming the composite shell of the thermal insulation process, the combination of thermal insulation film and rigid molds is used, resulting in poor appearance quality of the composite molding surface, unable to clearly shape edges and angles, and poor flatness of the plane, and the cost of preparing flexible molds separately is high.
Silicone surrounding film and rubber base film with reserved expansion and fusion gaps are used to form flexible molds with specific forms through thermal expansion and vulcanization, combining thermal insulation film and rigid molds to achieve the improvement of uniform conduction pressure and shaping capabilities.
It improves the clarity and flatness of edges and corners on the molding surface of the composite material, while reducing the production cost of flexible molds, providing an efficient molding solution.
Smart Images
Figure CN119189144A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the relevant fields of polymer materials and composite materials, in particular to a flexible mould for forming a composite material shell by a thermal diaphragm process. Background Art
[0002] The thermal diaphragm process composite shell molding is a composite molding method with outstanding stability. Specifically, composite prepreg is laid in a rigid mold, and a thermal diaphragm is covered on the composite prepreg. Pressure is applied to the thermal diaphragm through the high temperature vacuum negative pressure of the autoclave, so that the thermal diaphragm stretches and transmits pressure to all directions of the composite material, and the composite material is molded under high temperature. The thermal diaphragm has strong ductility but poor molding ability. If only the thermal diaphragm and the rigid mold are combined, the appearance quality of the composite molding surface in contact with the thermal diaphragm is poor, the edges and corners cannot be clearly molded, and the flatness of the plane is poor. The rigid mold has almost no ductility but strong molding ability. If a rigid mold is used in the thermal diaphragm composite shell molding process, the pressure transmission is uneven and the internal quality of the composite molding is poor. Flexible molds have a long history. They are generally made of fluid rubber, silicone and other materials vulcanized in the cavity mold. In the past, they needed to be opened separately for the thermal diaphragm process composite shell molding, which was costly. Summary of the invention
[0003] The present invention provides a flexible mold for composite material shell molding using a thermal diaphragm process to solve the technical problems that a thermal diaphragm and a rigid mold combination are used in the current thermal diaphragm process for composite material shell molding, the composite material molding surface in contact with the thermal diaphragm has poor appearance quality, the edges and corners cannot be clearly molded, and the plane flatness is poor, while the cost of preparing a flexible mold alone is high.
[0004] The present invention is implemented by adopting the following technical scheme: a flexible mold for forming a composite shell by a thermal diaphragm process, comprising a silicone edge film with a reserved expansion and fusion gap and a rubber bottom plate film with a reserved expansion and fusion gap; the rubber bottom plate film can be embedded in the silicone edge film.
[0005] The present invention aims to solve the technical problem of the contradiction between the molding capacity requirements of composite material forming molds under the thermal diaphragm process and the requirement of uniform pressure conduction capacity in all directions, and solves the technical problem of the contradiction between the molding capacity requirements of traditional composite material forming molds under the thermal diaphragm process and the high cost of opening a separate flexible mold.
[0006] Furthermore, the expansion and fusion gap on the silicone edge film refers to the gap opened on each edge of the silicone edge film, and the silicone edge film is cut into multiple sections along the gap, and the gap on each edge is perpendicular to the direction of the edge; the expansion and fusion gap on the rubber base film refers to the gap between the circumference of the rubber base film and the inner wall of the silicone edge film.
[0007] Further, the spacing d of the expansion fusion gap is determined according to the following formula: d = αLTk; Among them, α is the linear expansion coefficient of the film, L is the length of the side where the product gap is located, T is the difference between the material fusion temperature and the normal temperature, k is an empirical parameter, k=1.2 / β, β is the number of gaps (this number refers to the gap at the location when L is calculated).
[0008] Furthermore, when the thermal diaphragm process composite material shell molding flexible mold is used for thermal diaphragm process composite material shell molding, the following steps are adopted: calculating the spacing d of the expansion and fusion gaps of the silicone edge film and the rubber base film, and then preparing the silicone edge film with reserved expansion and fusion gaps and the rubber base film with reserved expansion and fusion gaps; covering the rigid mold with a release cloth; arranging the silicone edge film with reserved expansion and fusion gaps and the rubber base film with reserved expansion and fusion gaps on the release cloth; covering the silicone edge film with reserved expansion and fusion gaps and the rubber base film with reserved expansion and fusion gaps with release cloth and thermal diaphragm; applying high temperature and pressure to the thermal diaphragm through the high temperature vacuum negative pressure of the autoclave, so that the silicone edge film with reserved expansion and fusion gaps and the rubber base film with reserved expansion and fusion gaps are The rubber base film with fused gaps expands and fuses into a flexible mold for thermal diaphragm composite material shell molding; the flexible mold for thermal diaphragm composite material shell molding is taken out; the rigid mold is covered with a release cloth, and a composite material prepreg is placed; the composite material prepreg is covered with a release cloth, and a flexible mold for thermal diaphragm composite material shell molding is placed on it; the release cloth and thermal diaphragm are covered on the flexible mold for thermal diaphragm composite material shell molding; pressure is applied to the thermal diaphragm through the high temperature vacuum negative pressure of the autoclave, so that the thermal diaphragm is stretched to transmit pressure in all directions of the flexible mold for thermal diaphragm composite material shell molding, and the pressure causes the flexible mold for thermal diaphragm composite material shell molding to stretch to transmit pressure in all directions of the composite material and shape it, thereby molding the composite material under high temperature environment.
[0009] Furthermore, thermal expansion and vulcanization are used to form a silicone edge film with a reserved expansion and fusion gap in a specific shape and a rubber bottom plate film with a reserved expansion and fusion gap.
[0010] Furthermore, the silicone edge film and the rubber bottom film both have a "concave"-shaped structure; the silicone edge film is hollow inside, and the rubber bottom film can fill the hollow part of the silicone edge film.
[0011] The flexible mold has good ductility and shaping ability. It is placed between the thermal diaphragm and the composite material for supporting use, which can greatly improve the molding effect of the composite material molding surface that is in contact with the original thermal diaphragm. Flexible molds have a long history. They are generally formed by vulcanization molding of fluid rubber, silicone and other materials in a cavity mold. In the past, they needed to be separately molded for thermal diaphragm process composite material shell molding, which was costly. The thermal diaphragm process composite material shell molding flexible mold described in the present invention, through fusion calculation, only needs to lay a silicone edge film with a reserved expansion and fusion gap and a rubber bottom film with a reserved expansion and fusion gap in the existing thermal diaphragm process composite material shell molding mold, so that it can form a thermal diaphragm process film fusion molding flexible mold with a specific shape through thermal expansion and vulcanization, without the need to open another mold, which provides a new idea for thermal diaphragm process composite material shell molding.
[0012] The main innovation of the present invention is that, under the premise of thermal diaphragm technology, a flexible mold for forming a composite material shell by thermal diaphragm technology is cleverly constructed through the cooperation of a silicone surround with a reserved expansion and fusion gap and a rubber base with a reserved expansion and fusion gap. While ensuring that the pressure is fully transmitted in all directions of ductility, the shaping ability of thermal diaphragm molding is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 Schematic diagram of the flexible mold structure for composite shell molding using the thermal diaphragm process.
[0014] Figure 2 Schematic diagram of the silicone edge film structure with reserved expansion and fusion gaps.
[0015] Figure 3 Schematic diagram of the rubber base film structure with reserved expansion and fusion gaps.
[0016] 1-Silicone edge film, 2-Rubber base film, 3-Expansion fusion gap. DETAILED DESCRIPTION
[0017] Example 1 A flexible mold for forming a composite shell by a thermal diaphragm process, comprising a silicone edge film 1 with a reserved expansion and fusion gap 3 and a rubber base film 2 with a reserved expansion and fusion gap 3; the rubber base film 2 can be embedded in the silicone edge film 1. The expansion and fusion gap 3 on the silicone edge film 1 refers to the gap opened on each edge of the silicone edge film 1, and the silicone edge film 1 is cut into multiple sections along the gap, and the gap on each edge is perpendicular to the direction of the edge; the expansion and fusion gap 3 on the rubber base film 2 refers to the gap between the circumference of the rubber base film 2 and the inner wall of the silicone edge film 1. The spacing d of the expansion and fusion gap 3 is determined according to the following formula: d=αLTk; Wherein, α is the linear expansion coefficient of the film (when calculating the gap of the silicone edge film 1, the linear expansion coefficient of silicone is used; when calculating the gap of the rubber base film 2, the linear expansion coefficient of rubber is used), L is the side length of the product (when calculating the gap in the length direction, L=total length; when calculating the gap in the width direction, L=total width), T is the difference between the material fusion temperature and the normal temperature, k is an empirical parameter, k=1.2 / β, β is the number of gaps (this number is consistent with the calculation position of L. For the silicone edge film, when calculating the gap of a certain side, the gap width is calculated according to the number of gaps on that side, and the number of gaps is generally an empirical value; for the rubber base film, the gap of each side is 1).
[0018] Example 2 When the present invention is applied to composite material molding under a hot diaphragm process, the following steps are adopted: 1. A silicone edge film 1 with a reserved expansion fusion gap and a rubber base film 2 with a reserved expansion fusion gap are designed according to fusion calculation.
[0019] 2. Place the silicone edge film 1 with reserved expansion and fusion gaps and the rubber base film 2 with reserved expansion and fusion gaps into an existing molding mold, and form a hot diaphragm process film fusion molding flexible mold with a specific shape through thermal expansion and vulcanization in an autoclave.
[0020] 3. The flexible mold for thermal diaphragm process film fusion molding has good ductility and shaping ability. The specific working process is to cover the demoulding cloth in the rigid mold and lay the composite material prepreg; cover the demoulding cloth on the composite material prepreg and place the flexible mold for thermal diaphragm process composite material shell molding; cover the demoulding cloth on the flexible mold for thermal diaphragm process composite material shell molding, and then cover the thermal diaphragm; apply pressure to the thermal diaphragm through the high temperature vacuum negative pressure of the autoclave, so that the thermal diaphragm extends to transmit pressure in all directions to the flexible mold for thermal diaphragm process film fusion molding. This pressure makes the flexible mold for thermal diaphragm process composite material shell molding extend to transmit pressure in all directions to the composite material and shape it, so that the composite material is molded under high temperature environment. The use of the flexible mold for thermal diaphragm process film fusion molding can ensure the internal quality of the composite material molding while making the composite material molding surface in contact with the original thermal diaphragm present clear edges and smooth surfaces, greatly improving the composite material molding effect.
[0021] When placing the silicone edge film 1 composed of multiple silicone segments, it is necessary to separate the silicone segments by a partition with a calculated gap thickness, and then glue the bottom of each silicone segment together, and then remove the partition to complete the subsequent process.
[0022] Example 3 Figure 1-3As shown, the silicone edge film 1 and the rubber bottom film 2 are both in a "concave" shape; the silicone edge film 1 is hollow inside, and the rubber bottom film 2 can fill the hollow part of the silicone edge film 1. In actual application, the structural shapes of the silicone edge film 1 and the rubber bottom film 2 can also have other deformations, which are specifically designed according to actual conditions.
Claims
1. A flexible mold for forming a composite shell by a thermal diaphragm process, characterized in that: It comprises a silicone edge film (1) with a reserved expansion and fusion gap (3) and a rubber base film (2) with a reserved expansion and fusion gap (3); the rubber base film (2) can be embedded in the silicone edge film (1).
2. A flexible mold for forming a composite material shell by a thermal diaphragm process as claimed in claim 1, characterized in that: The expansion fusion gap (3) on the silicone edge film (1) refers to the gap opened on each edge of the silicone edge film (1), and the silicone edge film (1) is cut into multiple sections along the gap, and the gap on each edge is perpendicular to the direction of the edge; the expansion fusion gap (3) on the rubber base film (2) refers to the gap between the circumference of the rubber base film (2) and the inner wall of the silicone edge film (1).
3. A flexible mold for forming a composite material shell by a thermal diaphragm process as claimed in claim 2, characterized in that: The spacing d of the expansion fusion gap (3) is determined according to the following formula: d = αLTk; Among them, α is the linear expansion coefficient of the film, L is the length of the side where the product gap is located, T is the difference between the material fusion temperature and the normal temperature, k is an empirical parameter, k=1.2 / β, β is the number of gaps.
4. A flexible mold for forming a composite material shell by a thermal diaphragm process as claimed in claim 3, characterized in that: When the flexible mold for forming a composite shell by a thermal diaphragm process is used for forming a composite shell by a thermal diaphragm process, the following steps are adopted: calculating the spacing d of the expansion fusion gap (3) of the silicone edge film (1) and the rubber bottom film (2), then cutting and preparing the silicone edge film (1) with a reserved expansion fusion gap and the rubber bottom film (2) with a reserved expansion fusion gap; covering the rigid mold with a demoulding cloth; arranging the silicone edge film (1) with a reserved expansion fusion gap (3) and the rubber bottom film (2) with a reserved expansion fusion gap on the demoulding cloth. The rubber bottom plate film (2) is provided with a reserved expansion and fusion gap (3); a release cloth and a thermal insulation film are covered on the silicone edge film (1) and the rubber bottom plate film (2) provided with a reserved expansion and fusion gap (3); high temperature and pressure are applied to the thermal insulation film by means of a high temperature vacuum negative pressure of an autoclave, so that the silicone edge film (1) and the rubber bottom plate film (2) provided with a reserved expansion and fusion gap (3) expand and fuse to form a flexible mold for forming a composite material shell by a thermal insulation process; and the flexible mold for forming a composite material shell by a thermal insulation process is taken out; Cover the rigid mold with a release cloth and place the composite material prepreg; Cover the composite material prepreg with a release cloth and place a flexible mold for forming a composite material shell by a thermal insulation process on it; Cover the flexible mold for forming a composite material shell by a thermal insulation process with a release cloth and a thermal insulation film; Through the high temperature vacuum negative pressure of the autoclave, pressure is applied to the hot diaphragm, causing the hot diaphragm to stretch and transmit pressure in all directions to the flexible mold for forming the composite material shell of the hot diaphragm process. The pressure causes the flexible mold for forming the composite material shell of the hot diaphragm process to stretch and transmit pressure in all directions to the composite material and shape it, thereby forming the composite material under a high temperature environment.
5. A flexible mold for forming a composite material shell by a thermal diaphragm process as claimed in any one of claims 1 to 4, characterized in that: Thermal expansion and vulcanization are used to form a silicone edge film (1) with a reserved expansion and fusion gap (3) in a specific shape and a rubber base film (2) with a reserved expansion and fusion gap (3).
6. A flexible mold for forming a composite material shell by a thermal diaphragm process as claimed in any one of claims 1 to 4, characterized in that: The silicone edge film (1) and the rubber base film (2) both have a "concave"-shaped structure; the silicone edge film (1) is hollow inside, and the rubber base film (2) can fill the hollow part of the silicone edge film (1).