Forming tool for variable cross-section composite material barrel

Abstract

The utility model discloses a forming tool for a variable cross-section composite material barrel. The forming tool comprises a first end cover, a second end cover, an upper die and a lower die, wherein the upper die and the lower die are provided with molded surfaces matched with the outer surface of the variable cross-section composite material barrel; and the composite core mold is provided with a molded surface matched with the inner surface of the variable cross-section composite material barrel, the composite core mold is located in a cavity defined by the upper mold, the lower mold, the first end cover and the second end cover, and a cavity used for forming the variable cross-section composite material barrel is defined by the upper mold, the lower mold and the composite core mold. The integral male die is made of low-melting-point alloy, thermal damage of high temperature to the composite barrel is avoided, secondary machining of the molded surface of the male die is not needed, the molded surface is smooth, the manufacturing period is short, and the comprehensive cost is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of composite material cylinder molding, and in particular relates to a variable-section composite material cylinder molding tool. Background Art

[0002] Composite materials have the characteristics of high specific strength and specific stiffness. More and more metal cylinders are changed to composite materials. Among them, variable-section cylinders are used in specific structures. Gas or liquid flows through the cylinders, and there are high requirements for the smoothness of the inner surface of the cylinder. In order to facilitate the laying of the variable-section composite cylinder and ensure the smoothness of the inner surface of the cylinder after molding, the variable-section composite cylinder usually adopts a positive mold solution.

[0003] The advantage of the positive mold scheme is that the inner profile of the cylinder is the mold-fitting surface, and the surface quality of the inner profile of the cylinder is guaranteed by the mold, which can meet the index requirements of the smoothness of the inner surface of the cylinder. However, the variable-section composite cylinder structure will make it impossible to demold the positive mold in an integrated manner after molding. One solution is to divide the metal mold into blocks and take them out from the port of the cylinder respectively. Due to the changes in the profile of the composite cylinder, the forming method of the positive mold block often requires the positive mold to be complexly divided, the mold matching precision is high, the assembly and disassembly process is complex, and the comprehensive cost is high. The other is the integral positive mold scheme. The positive mold can be made of a low-melting point alloy. The traditional low-melting point alloy mold forming scheme needs to select a low-melting point alloy with a melting point higher than the curing temperature of the composite material and lower than the glass transition temperature of the composite material to ensure that when the low-melting point alloy is subsequently heated and taken out of the composite material part, it will not cause thermal damage to the composite material due to excessive temperature. At the same time, in order to ensure the smoothness of the molding surface, the low-melting point alloy positive mold surface needs to be processed for smoothing, the manufacturing cycle is long, and the comprehensive cost is relatively high. Utility Model Content

[0004] In order to solve the deficiencies in the prior art, the utility model provides a variable-section composite material cylinder forming tooling, which adopts an integral male mold solution made of a low-melting-point alloy, thereby avoiding thermal damage to the composite material cylinder caused by high temperature, and does not require secondary processing of the male mold surface. The forming surface is smooth, the manufacturing cycle is short, and the overall cost is low.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is:

[0006] In a first aspect, a tooling for forming a variable-section composite cylinder is provided, comprising: a first end cover, a second end cover, an upper mold and a lower mold having a profile that matches the outer surface of the variable-section composite cylinder; a composite core mold having a profile that matches the inner surface of the variable-section composite cylinder, the composite core mold being located in a cavity formed by the upper mold, the lower mold, the first end cover and the second end cover, and the upper mold, the lower mold and the composite core mold forming a cavity for forming a variable-section composite cylinder.

[0007] Furthermore, the composite core mold includes: a central axis; a low-melting-point alloy core cast on the outer surface of the central axis, with a melting point lower than the curing molding temperature of the variable-section composite material cylinder; a rubber layer cast on the outer surface of the low-melting-point alloy core, with a maximum operating temperature greater than the curing molding temperature of the variable-section composite material cylinder, wherein the outer surface of the rubber layer is a profile that matches the inner surface of the variable-section composite material cylinder.

[0008] Furthermore, the central axis is a hollow axis with both ends closed.

[0009] Furthermore, the alloy used for casting the low-melting-point alloy core includes at least two of Bi, Pb, Sn, Sb, Zn, Cd, In, and Ga.

[0010] Furthermore, both ends of the rubber layer are provided with flanges, and the flanges are respectively clamped between the first end cover and the first end faces of the upper mold and the lower mold, and between the second end cover and the second end faces of the upper mold and the lower mold.

[0011] Furthermore, the first end cover and the second end cover are both provided with sealing grooves for accommodating the flanges.

[0012] Furthermore, the first end cover and / or the second end cover are provided with an air inlet and an air outlet, and the air inlet and the air outlet are both communicated with the space where the low-melting-point alloy core is located.

[0013] Furthermore, it also includes a core mold casting mold for molding the low-melting-point alloy core and a rubber casting mold for molding the rubber layer.

[0014] In a second aspect, a method for forming a variable-section composite material cylinder is provided, using the variable-section composite material cylinder forming tooling described in the first aspect, the method comprising: making a composite core mold; laying composite material layers on the mold surface of the composite core mold in a set manner to form a variable-section composite material cylinder to be cured, and placing the entirety into a cavity surrounded by an upper mold, a lower mold, a first end cover, and a second end cover; heating the variable-section composite material cylinder forming tooling to the curing molding temperature of the variable-section composite material cylinder to complete the curing molding; and demolding to complete the production of the variable-section composite material cylinder.

[0015] Furthermore, the composite core mold is manufactured, including: installing the central axis in the core mold casting mold, heating and melting the low-melting point alloy, casting it in the core mold casting mold, and solidifying the low-melting point alloy after cooling to form a low-melting point alloy core; configuring the main agent and curing agent of the rubber according to a set ratio, vacuuming and vibrating to degassing; installing the low-melting point alloy core in the rubber casting mold, pouring the degassed rubber into the rubber casting mold, vulcanizing at room temperature or heating to obtain a rubber layer, and forming a final composite core mold.

[0016] Furthermore, the melting point of the low-melting-point alloy core is lower than the curing molding temperature of the variable-section composite material cylinder; and the maximum use temperature of the rubber layer is higher than the curing molding temperature of the variable-section composite material cylinder.

[0017] Furthermore, the thickness of the rubber layer is 0.5 to 10 mm, the elongation at break is greater than 100%, the tensile strength is greater than 2 MPa, and the Shore hardness is greater than 50 HA.

[0018] Furthermore, the variable-section composite material cylinder molding tool is heated to the curing molding temperature of the variable-section composite material cylinder to complete the curing molding, including: first, introducing compressed gas into the space where the low-melting-point alloy core of the composite core mold is located through the air inlet arranged on the second end cover, and sealing the air outlet arranged on the second end cover; then heating the variable-section composite material cylinder molding tool to the curing molding temperature of the variable-section composite material cylinder, at which time, the low-melting-point alloy core melts into molten alloy, and under the action of the compressed gas, the molten alloy forms an internal molding pressure of the variable-section composite material cylinder through the rubber layer.

[0019] Furthermore, the demolding includes: first opening the air outlet on the second end cover, and the molten alloy is discharged through the air outlet under the push of compressed gas; after the variable-section composite material cylinder molding tool is cooled to room temperature, the first end cover and the second end cover are opened, and the rubber layer and the center axis of the composite core mold are pulled out; finally, the upper mold and the lower mold are removed.

[0020] Furthermore, the pressure of the compressed gas is 0.1 MPa to 1 MPa.

[0021] Compared with the prior art, the beneficial effects achieved by the utility model are as follows: the utility model comprises a first end cover, a second end cover, an upper mold and a lower mold having a profile matching the outer surface of a variable-section composite material cylinder, and a composite core mold having a profile matching the inner surface of the variable-section composite material cylinder. The composite core mold is located in a cavity surrounded by the upper mold, the lower mold, the first end cover and the second end cover, and the upper mold, the lower mold and the composite core mold form a cavity for molding a variable-section composite material cylinder. The composite core mold is an integral positive mold solution made of a low-melting-point alloy, which avoids thermal damage to the composite material cylinder caused by high temperature, and does not require secondary processing of the profile of the positive mold. The molding surface is smooth, the manufacturing cycle is short, and the overall cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a process flow chart of the molding process of the composite core mold in the embodiment of the utility model;

[0023] Figure 2 This is a process flow chart of the molding process of a variable cross-section composite material cylinder in an embodiment of the utility model;

[0024] Figure 3 It is a schematic diagram of the longitudinal section structure of a variable cross-section composite material cylinder forming tool provided by an embodiment of the utility model;

[0025] Figure 4 yes Figure 3 A partial enlarged view of

[0026] Figure 3 , Figure 4 Middle: 1. Upper mold; 2. Lower mold; 3. Composite core mold; 31. Central axis; 32. Low melting point alloy core; 33. Rubber layer; 4. First end cover; 5. Second end cover; 6. Air inlet; 7. Air outlet; A. Variable cross-section composite material cylinder. DETAILED DESCRIPTION

[0027] The utility model is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and cannot be used to limit the protection scope of the utility model.

[0028] Embodiment 1:

[0029] like Figure 3 , Figure 4 As shown, a variable cross-section composite cylinder forming tool includes: a first end cover 4, a second end cover 5, an upper mold 1 and a lower mold 2 having a profile matching the outer surface of the variable cross-section composite cylinder, and a composite core mold 3 having a profile matching the inner surface of the variable cross-section composite cylinder. The composite core mold 3 is located in a cavity surrounded by the upper mold 1, the lower mold 2, the first end cover 4 and the second end cover 5, and the upper mold 1, the lower mold 2 and the composite core mold 3 form a cavity for forming a variable cross-section composite cylinder.

[0030] The composite core mold 3 includes: a central axis 31; a low-melting-point alloy core 32 cast on the outer surface of the central axis 31, with a melting point lower than the curing molding temperature of the variable-section composite material cylinder; a rubber layer 33 cast on the outer surface of the low-melting-point alloy core 32, with a maximum operating temperature higher than the curing molding temperature of the variable-section composite material cylinder, and the outer surface of the rubber layer 33 is a profile that matches the inner surface of the variable-section composite material cylinder.

[0031] The composite materials used to make variable-section composite cylinders are usually divided into medium-temperature 120°C curing, high-temperature 180°C curing and above 200°C curing material systems according to the curing molding temperature.

[0032] The composite core mold 3 in the utility model adopts a composite structure of a central axis 31, a low melting point alloy core 32, and a rubber layer 33. The low melting point alloy core of the composite core mold is formed by a low melting point alloy and is cast by a low melting point alloy. The low melting point alloy generally refers to a binary, ternary, and other multi-element alloy containing metal elements such as Bi, Pb, Sn, Sb, Zn, Cd, In, and Ga, and the melting point ranges from 70°C to 310°C.

[0033] In the present invention, when the curing molding temperature of the composite material is a medium temperature curing of 120°C, the low melting point alloy combination that can be selected includes: 34% Bi-66% In, with a melting point of 72°C;

[0034] When the curing molding temperature of the composite material is high temperature 180℃, the low melting point alloy combination that can be used includes: 44.5%Pb-55.5%Bi, melting point: 124℃;

[0035] When the curing molding temperature of the composite material is above 200°C, the low melting point alloy combination that can be used includes: 61.9% Sn-38.1% Pb, with a melting point of 183°C.

[0036] The outermost layer of the composite core mold 3 is a rubber layer 33 covering the outer surface of the low melting point alloy core 32. The outer surface of the rubber layer 33 and the variable cross-section composite material cylinder A (such as Figure 3 , Figure 4 The rubber layer 33 can be formed by mold casting and curing. The rubber consists of two components, a main agent and a curing agent, and can be vulcanized at room temperature or under heating conditions. The maximum operating temperature of the rubber layer 33 must be greater than the curing molding temperature of the variable cross-section composite material cylinder A, the elongation at break is greater than 100%, the tensile strength is greater than 2MPa, and the Shore hardness is greater than 50HA. The thickness of the rubber layer is between 0.5 and 10mm. After the rubber is vacuumed and vibrated to degas, it is poured at 0.1 to 1Mpa or normal pressure.

[0037] The middle structure of the composite core mold 3 is the central axis 31, which is usually a hollow steel shaft. The low-melting-point alloy part of the composite core mold 3 forms the inner profile of the variable-section composite cylinder A. The hollow steel shaft is used to reduce the amount of low-melting-point alloy, reduce the cost of the core mold, increase the rigidity of the core mold, and reduce the weight of the core mold. The two ends of the hollow steel shaft are closed structures. According to the complexity of the profile of the variable-section composite cylinder A, the structure can be integral or segmented, which is easy to remove from the cylinder port.

[0038] The manufacturing process of the composite core mold 3 includes: installing the central shaft 31 in the core mold casting mold, heating and melting the low melting point alloy, casting it in the core mold casting mold, and cooling the low melting point alloy to solidify to form a low melting point alloy core 32. The main agent and curing agent of the rubber are configured in a certain proportion, and vacuum and vibration degassing treatment is performed. The low melting point alloy core 32 is installed in the rubber casting mold, and the degassed rubber is poured into the rubber casting mold, vulcanized at room temperature or heated to obtain a rubber layer 33, and the final composite core mold 3 is formed. The process flow chart of the composite core mold is shown in FIG. Figure 1 shown.

[0039] The molding method of the variable cross-section composite material cylinder A comprises: laying a composite material layer on the surface of the composite core mold 3 to form a composite material cylinder of variable cross-section to be cured, and placing it in a composite material cylinder molding tool of variable cross-section. The molding tool is a female mold combination structure, mainly composed of an upper mold 1, a lower mold 2, a first end cover 4, and a second end cover 5, and forms a closed space. The rubber layer 33 of the cast composite core mold 3 is provided with flanges at both ends, and the first end cover 4 and the second end cover 5 are respectively provided with sealing grooves for accommodating the flanges of the rubber layer 33. The rubber flanges are pressed, and the first end cover 4, the second end cover 5 and the upper mold 1 and the lower mold 2 form a closed inner cavity surrounding the composite core mold 3. The second end cover 5 (which can also be the first end cover 4) is provided with an air inlet 6 and an air outlet 7 in the vertical up and down directions, and is connected to the low melting point alloy part of the composite core mold 3 through the opening in the second end cover 5. The upper mold and the lower mold are formed by a female mold, and the outer surface of the composite material cylinder of variable cross-section is controlled by the mold surface, and the appearance quality is good.

[0040] The above-mentioned variable cross-section composite cylinder forming tool is placed in an oven for heating, and compressed gas is introduced into the mold cavity through the air inlet 6 of the second end cover 5, with a compressed gas pressure of 0.1MPa~1Mpa, and the air outlet of the second end cover 5 is closed. The temperature in the forming tool rises to the melting point temperature of the low-melting-point alloy, and the low-melting-point alloy melts into molten metal. Under the action of compressed gas, the molten low-melting-point alloy forms the internal forming pressure of the variable cross-section composite cylinder A through the rubber layer 33, and the inner surface of the variable cross-section composite cylinder is pressurized and formed through the rubber layer. The inner surface of the cylinder is smooth and has good appearance quality. The temperature of the forming tool is further raised to the curing temperature of the variable cross-section composite cylinder A, and after the curing and forming is completed, the air outlet 7 of the second end cover 5 is opened, and the liquid low-melting-point alloy is discharged through the air outlet 7 under the push of compressed gas. After the variable cross-section composite cylinder A is cured and formed, the tool is cooled to room temperature. After the tooling is opened, the low-melting-point alloy of the composite core mold 3 has flowed out, forming an internal cavity. The remaining rubber layer 33 and the center axis 31 can be directly taken out from the variable-section composite material cylinder A, which is simple and efficient to operate. The cast rubber layer 33 can be reused, which is economical. The low-melting-point alloy can be used for casting new core molds and reused, which is economical. The utility model connects compressed gas and pressurizes the inner mold surface of the variable-section composite material cylinder with molten low-melting-point alloy, so that the heating and curing of the variable-section composite material cylinder can be completed in an oven, avoiding the use of an autoclave for curing and reducing the curing molding cost. The molding process flow chart of the variable-section composite material cylinder is shown in the figure. Figure 2 shown.

[0041] Embodiment 2

[0042] Based on the variable-section composite material cylinder forming tool described in the first embodiment, this embodiment provides a variable-section composite material cylinder forming method, including:

[0043] (1) Making a composite core mold 3, specifically:

[0044] The central shaft 31 is installed in the core mold casting mold, the low melting point alloy is heated and melted, and cast in the core mold casting mold, and the low melting point alloy solidifies after cooling to form a low melting point alloy core 32;

[0045] The main agent and curing agent of rubber are prepared in a set ratio, and vacuum and vibrate to degas.

[0046] The low melting point alloy core 32 is installed in the rubber casting mold, the degassed rubber is poured into the rubber casting mold, and vulcanized at room temperature or by heating to obtain a rubber layer 33 and form the final composite core mold 3.

[0047] (2) Laying the composite material layer on the mold surface of the composite core mold 3 in a set manner to form a composite material cylinder with a variable cross-section to be cured, and placing the entire cylinder into a cavity surrounded by the upper mold 1, the lower mold 2, the first end cover 4 and the second end cover 5.

[0048] (3) Heating the variable cross-section composite material cylinder forming tooling to the curing forming temperature of the variable cross-section composite material cylinder to complete the curing forming, specifically:

[0049] First, the compressed gas is introduced into the space where the low melting point alloy core 32 of the composite core mold 3 is located through the air inlet 6 provided on the second end cover 5, and the air outlet 7 provided on the second end cover 5 is blocked;

[0050] The variable cross-section composite material cylinder molding tool is then heated to the curing molding temperature of the variable cross-section composite material cylinder. At this time, the low melting point alloy core 32 melts into molten alloy. Under the action of compressed gas, the molten alloy passes through the rubber layer 33 to form internal molding pressure of the variable cross-section composite material cylinder.

[0051] (4) Demolding to complete the production of the variable cross-section composite material cylinder, specifically:

[0052] First, the gas outlet 7 on the second end cover 5 is opened, and the molten alloy is discharged through the gas outlet 7 under the push of the compressed gas;

[0053] The variable cross-section composite cylinder molding tool is cooled to room temperature, the first end cover 4 and the second end cover 5 are opened, and the rubber layer 33 and the central axis 31 of the composite core mold 3 are pulled out;

[0054] Finally, the upper mold 1 and the lower mold 2 are removed.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A variable cross-section composite material cylinder forming tool, characterized in that: include: A first end cover (4), a second end cover (5), an upper mold (1) and a lower mold (2) having a profile matching the outer surface of a variable-section composite material cylinder; A composite core mold (3) having a molding surface matching the inner surface of a variable-section composite material cylinder, the composite core mold (3) being located in a cavity surrounded by the upper mold (1), the lower mold (2), the first end cover (4) and the second end cover (5), and the upper mold (1), the lower mold (2) and the composite core mold (3) forming a molding cavity for molding the variable-section composite material cylinder.

2. The variable cross-section composite material cylinder forming tool according to claim 1, characterized in that: The composite core mold (3) comprises: Central axis (31); A low melting point alloy core (32) cast on the outer surface of the central shaft (31) and having a melting point lower than the solidification molding temperature of the variable cross-section composite material cylinder; A rubber layer (33) is cast on the outer surface of the low-melting-point alloy core (32), the maximum use temperature of which is greater than the curing molding temperature of the variable-section composite material cylinder, and the outer surface of the rubber layer (33) is a profile that matches the inner surface of the variable-section composite material cylinder.

3. The variable cross-section composite material cylinder forming tool according to claim 2, characterized in that: The central shaft (31) is a hollow shaft with both ends closed.

4. The variable cross-section composite material cylinder forming tool according to claim 2, characterized in that: Both ends of the rubber layer (33) are provided with flanges, and the flanges are respectively clamped between the first end cover (4) and the first end faces of the upper mold (1) and the lower mold (2), and between the second end cover (5) and the second end faces of the upper mold (1) and the lower mold (2).

5. The variable cross-section composite material cylinder forming tool according to claim 4, characterized in that: The first end cover (4) and the second end cover (5) are both provided with a sealing groove for accommodating the flange.

6. The variable cross-section composite material cylinder forming tool according to claim 2, characterized in that: An air inlet (6) and an air outlet (7) are provided on the first end cover (4) and / or the second end cover (5), and the air inlet (6) and the air outlet (7) are both in communication with the space where the low-melting-point alloy core (32) is located.

7. The variable cross-section composite material cylinder forming tool according to claim 2, characterized in that: It also includes a core mold casting mold for molding the low-melting-point alloy core (32), and a rubber casting mold for molding the rubber layer (33).

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