RTM (Resin Transfer Molding) curing forming structure for long and thin L-shaped composite part
Through RTM molding structure and mold design, the thickness accuracy and surface quality problems of slender L-shaped composite parts are solved, and high-precision and efficient manufacturing of composite parts are achieved, reducing costs.
Patent Information
- Application Number
- CN202421908808.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-08-07
AI Technical Summary
The thickness accuracy of the slender L-shaped composite parts cannot be guaranteed and the surface quality is not ideal. The traditional molding method has problems such as demolding and inaccurate molding.
The RTM molding structure is adopted, including the right mold half, the left mold half and the upper mold. The rubber injection port and the rubber outlet are set according to the shape of the part, combined with thermal deformation analysis and mold design, to ensure the sealing and airtightness of the mold clamping, and to manufacture composite parts through the RTM process.
The precise thickness and smooth surface of composite parts are achieved, the profile accuracy and processing efficiency are improved, the manufacturing cost is reduced, and the mold deformation and inaccurate profile are avoided.
Smart Images
Figure CN222904921U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of aviation composite material forming, and particularly relates to an RTM curing forming structure for an elongated L-shaped composite part. Background Art
[0002] For an elongated L-shaped composite part, one side is a plane, and the other side is a single-sided parabolic curved surface. The two sides form an approximate acute angle, with characteristics such as large curvature, high forming difficulty, and difficult demolding. If traditional forming methods are used, the thickness accuracy of the part cannot be guaranteed, and the surface quality cannot reach an ideal effect. Summary of the Utility Model
[0003] The utility model aims to solve the problems that the thickness accuracy of the elongated L-shaped composite part during forming cannot be guaranteed and the surface quality cannot reach an ideal effect, and further provides an RTM curing forming structure for an elongated L-shaped composite part.
[0004] The technical solution adopted by the utility model is as follows:
[0005] An RTM curing forming structure for an elongated L-shaped composite part includes a right half mold, a left half mold, and an upper mold; the right half mold is provided with a right cavity, the left half mold is provided with a left cavity, and the cavity formed after the left half mold, the right half mold, and the upper mold are closed is the forming cavity of the part. A plurality of glue injection ports are arranged on the upper mold, and the glue injection ports are respectively arranged at the highest point, the lowest point, and the four corners according to the shape of the part. A plurality of glue outlet ports are arranged on the left half mold, and the glue outlet ports are respectively arranged at the lowest point, the lower left corner, and the lower right corner according to the shape of the part.
[0006] The utility model has the following beneficial effects compared with the prior art:
[0007] 1. The utility model adopts the RTM forming method, which can manufacture composite parts with complex surfaces, precise thickness, and smooth front and back surfaces. The utility model can ensure the accuracy of its structural dimensions, the sealing of the butt joints of each component is reliable, and it is convenient for mold closing and mold opening, and can solve the problems existing in traditional forming methods.
[0008] 2. The contour accuracy of the combined surface of the utility model is ±0.1 mm, which can improve the surface accuracy of the product, and the manufactured parts have high accuracy and low porosity. The parts formed by the utility model have stable dimensions, high production efficiency, and low cost.
[0009] 3. The utility model can avoid the influence of factors such as mold deformation and inaccurate surface, improve the processing and manufacturing efficiency, greatly improve the problem of time-consuming and laborious processing, significantly shorten the manufacturing cycle, and reduce the manufacturing cost. Description of the Drawings
[0010] Figure 1 is an isometric view of the utility model;
[0011] Figure 2 is a sectional view of the utility model;
[0012] Figure 3 is a front view of the utility model;
[0013] Figure 4 is an axonometric view of the right half mold of the utility model;
[0014] Figure 5 is an axonometric view of the left half mold of the utility model;
[0015] Figure 6 is an axonometric view of the upper mold of the utility model;
[0016] Figure 7 is a schematic structural view of a slender L-shaped composite part;
[0017] Among them: 1. Right half mold; 2. Left half mold; 3. Upper mold; 4. Hexagon bolt II; 5. Hexagon nut; 6. Flat washer II; 7. Elastic washer II; 8. Sealing strip II; 9. Pilot pin II; 10. Hexagon bolt I; 11. Flat washer I; 12. Elastic washer I; 13. Plug I; 14. Polytetrafluoroethylene gasket; 15. Plug II; 101. Right cavity; 102. Pilot pin I; 103. Guide bushing I; 104. Hoisting ring I; 201. Left cavity; 202. Guide bushing II; 203. Guide bushing III; 204. Drill bushing; 205. Sealing strip I; 206. Hoisting ring II; 301. Hoisting ring III. Detailed implementation mode
[0018] In order to better understand the purpose, structure and function of the utility model, the following further detailed description of the utility model will be made with reference to the accompanying drawings.
[0019] As Figures 1 to 6 shown, the utility model provides an RTM curing and forming structure for a slender L-shaped composite part, including a right half mold 1, a left half mold 2 and an upper mold 3; the right half mold 1 is provided with a right cavity 101, the left half mold 2 is provided with a left cavity 201, and the cavity formed after the left half mold 2, the right half mold 1 and the upper mold 3 are closed is the forming cavity of the part. The upper mold 3 is provided with a plurality of injection ports, and the injection ports are respectively arranged at the highest point, the lowest point and the four corners according to the shape of the part. The left half mold 2 is provided with a plurality of glue outlet ports, and the glue outlet ports are respectively arranged at the lowest point and the lower left and lower right corners according to the shape of the part.
[0020] As Figure 4 shown, two pilot pins I 102 are embedded in the butt joint surface of the right half mold 1, and the right half mold 1 is positioned with the left half mold 2 through the pilot pins I 102. Two guide bushings I 103 are embedded in the upper surface of the right half mold 1, and the right half mold 1 is butt-jointed and positioned with the upper mold 3 through the guide bushings I 103, and a hoisting ring I 104 is installed on the outer side surface of the right half mold 1.
[0021] As shown Figure 5 in the figure, two second guide sleeves 202 are embedded in the docking surface of the left half mold 2, and are docked and positioned with the first alignment pins 102 of the right half mold 1 through the second guide sleeves 202. Two third guide sleeves 203 are embedded in the upper surface of the left half mold 2 and are docked and positioned with the upper mold 3 through the third guide sleeves 203. A drill bushing 204 is embedded at the position of the process lug in the part allowance area in the left cavity 201 of the left half mold 2. A first sealing groove is opened around the left cavity 201 on the docking surface of the left half mold 2, and a first sealing strip 205 is placed in the first sealing groove. A second lifting ring 206 is installed on the outer side surface of the left half mold 2.
[0022] As shown Figure 6 in the figure, a third lifting ring 301 is installed on the upper mold 3.
[0023] As shown Figure 2 in the figure, a second sealing groove is opened around the outside of the left cavity 201 on the upper surface of the left half mold 2, and a third sealing groove is opened around the outside of the right cavity 101 on the upper surface of the right half mold 1. A second sealing strip 8 is placed in the second sealing groove and the third sealing groove.
[0024] As shown Figure 3 in the figure, the third guide sleeves 203 of the left half mold 2 and the first guide sleeves 103 of the right half mold 1 are positioned with the upper mold 3 by using the second alignment pins 9 and are connected by the first hexagon head bolts 10. A first flat washer 11 and a first elastic washer 12 are provided between the first hexagon head bolts 10 and the upper mold 3.
[0025] As shown Figure 2 in the figure, the right half mold 1 and the left half mold 2 are connected by the second hexagon head bolts 4 and hexagon nuts 5. A second flat washer 6 and a second elastic washer 7 are provided between the heads of the second hexagon head bolts 4 and the left half mold 2.
[0026] As shown Figure 2 in the figure, the drill bushing 204 is blocked by a first plug 13, and a polytetrafluoroethylene gasket 14 is added between the drill bushing 204 and the first plug 13.
[0027] As shown Figure 1 and Figure 2 in the figure, multiple injection ports of the upper mold 3 and multiple glue outlets of the left half mold 2 are blocked by second plugs 15.
[0028] The utility model adopts the RTM curing and forming structural method.
[0029] Step 1: Conduct a theoretical analysis on the thermal deformation of the RTM forming mold for the slender L-shaped composite part. When the pressure in the cavity is 0.6 MPa, the analysis result meets the requirement that the deformation amount ≤ 0.1 mm. Only then can the mold manufacturing, assembly, inspection and other work be carried out.
[0030] First, use the fluid simulation module of the 3D software SolidWorks to conduct a thermal deformation analysis of the mold. Through reasonable parameter settings, mesh generation, etc., make a preliminary prediction of the deformation of the mold under high-temperature conditions. By finely modifying the model, pre-judge whether the structure is reasonable in advance, avoid insufficient stiffness of the tooling, and specifically improve the mold structure to avoid cost waste caused by frequent changes to the actual tooling or scrapping due to changes.
[0031] Step 2: Move each component of the mold into the purification room, clean the mold surface, and pre-detect the mold closing state. Use a vacuum pump to draw negative pressure. If the pressure reaches -0.1 MPa and there is no air leakage, insert the alignment pin 102 into the docking surface of the right half mold 1, and the exposed surface part is positioned with the left half mold 2. Insert the guide bushing 103 into the upper surface of the right half mold 1, and install the lifting ring 104 to ensure that the right half mold 1 can be transported and flipped. At this time, the right half mold 1 is ready.
[0032] Step 3: Brush the mold release agent on the surface of the right half mold 1. The laminating worker completes the laying of the L-shaped composite part (dry fiber) according to the process production drawing.
[0033] Step 4: Insert the guide bushing 202 into the docking surface of the left half mold 2, insert the guide bushing 203 into the upper surface of the left half mold 2, insert the drill bushing 204 into the position of the process lug in the part allowance area of the left cavity 201, place the sealing strip 205 in the first sealing groove of the left half mold 2, install the lifting ring 206 to ensure that the left half mold 2 can be transported and flipped. Brush the mold release agent on the surface of the left half mold 2. At this time, the left half mold 2 is ready.
[0034] In Step 4, since a process hole needs to be drilled after the tooling is formed, the tooling needs to be designed with a drill bushing and a drill bushing installation hole, which will cause air leakage during the forming process of the tooling. Therefore, weld a circular convex block on the left half mold 2, machine a drill bushing installation hole and a drill bit through hole (i.e., a stepped hole) in the surface of the left half mold 2, and insert the drill bushing 204. The outer circle of the circular convex platform on the back of the left half mold 2 needs to be machined into an external taper pipe thread, and a plug 13 (internal taper pipe thread) is designed. The plug 13 needs to be installed during forming, and the plug 13 and the PTFE gasket 14 are removed for drilling when drilling the process hole.
[0035] Step 5: Install the lifting ring 301 on the upper mold 3 to ensure that the upper mold 3 can be transported and flipped. Brush the mold release agent on the surface of the upper mold 3. At this time, the upper mold 3 is ready.
[0036] Step 6: Position the right half mold 1 in Step 3 and the left half mold 2 in Step 4 through the alignment pin 102 and the guide bushing 202, and connect them with high-strength hexagon bolts 4, high-strength large hexagon nuts 5 for steel structures, flat washers 6, and elastic washers 7 to complete the combination of the right half mold 1 and the left half mold 2. At the same time, use a feeler gauge to detect whether the left and right half molds are closed in place.
[0037] Step 7: After the right half mold 1 and the left half mold 2 are closed, place the second sealing strip 8 in the sealing groove on the upper surfaces of the right half mold 1 and the left half mold 2. Position it with the second alignment pin 9 with the upper mold 3, and then connect them through the high-strength hexagon bolts 10, flat washers 11, and elastic washers 12 to complete the positioning connection between the upper mold 3 and the right half mold 1 and the left half mold 2. At the same time, use a feeler gauge to detect whether the right half mold 1, the left half mold 2 and the upper mold 3 are properly closed.
[0038] In Steps 6 and 7, the positioning and connection form between the left half mold 2 and the right half mold 1: The left half mold 2 and the right half mold 1 are positioned by the first alignment pin 102. The end of the first alignment pin 102 is designed with a 30×10° chamfer, which can facilitate the quick alignment and closing of the left and right half molds. They are connected by high-strength hexagon bolts 4 for steel structures and high-strength large hexagon nuts 5 for steel structures to ensure good sealing performance of the butting surface.
[0039] Step 8: Plug the drill bushing 204 with the first plug 13 (add a polytetrafluoroethylene gasket 14 between the drill bushing 204 and the first plug 13 to enhance the airtightness between the drill bushing 204 and the first plug 13 by using its elasticity). Plug the resin inlet of the upper mold 3 and the resin outlet of the left half mold 2 with the second plug 15. At this time, the airtightness of the mold needs to be detected. It is required that the vacuum degree in the internal sealed cavity of the mold is not lower than 0.095 Mpa. When the vacuum source is closed, the vacuum loss ≤ 0.017 MPa / 5 min.
[0040] Step 9: Use the resin tank to inject resin into the sealed mold cavity through the resin inlet. The resin flows in the mold and infiltrates the reinforcing material. Observe that the resin overflows from the resin overflow port of the mold and no more bubbles are discharged, and when the actually added resin amount is basically the same as the expected added resin amount, the transfer process is completed.
[0041] In Steps 8 and 9, the number and arrangement positions of the resin injection ports on the upper mold 3 and the number and arrangement positions of the resin outlets on the left half mold 2 are the key to the RTM curing and forming of the slender L-shaped composite parts, and are also related to the shape of the parts themselves. In this tooling case, the L-shaped part is placed with a certain angle of inclination on the upper plane and the other side is close to vertical downward. Therefore, the resin injection ports on the upper mold 3 are set at the highest point and the lowest point, including the four corner positions, with an arrangement spacing of about 250 mm. The resin outlets are set at a position about 50 mm along the lower surface contour of the left half mold 2, with a spacing of about 250 mm, including the lowest point and the left and right bottom corners. This avoids uneven resin injection and affects the final forming thickness of the parts.
[0042] Step Ten: After the injection molding is completed, move the mold into the autoclave, heat it up to (80±5)°C at a heating rate of 2°C / min, keep it warm for 0.5 h, then heat it up to (180±5)°C and keep it warm for 1.5 h. After the curing is completed, when the mold is cooled down to below 60°C at a cooling rate of 2°C / min, the molded mold can be taken out of the autoclave, the plug 13 and the PTFE gasket 14 are disassembled, and the hole is drilled using an alloy drill bit. At this time, with the help of the demolding jackscrew and the wrench, the upper mold 3 and the left half mold 2 are disassembled in sequence to complete the demolding of the L-shaped composite part.
[0043] Step Eleven: Trim the slender L-shaped composite part to the final state according to the outline line.
[0044] Using this method for molding, a slender L-shaped composite part with a length of about 3 m can be produced. One side is a plane, and the other side is a single-sided parabolic curved surface. The two sides form a composite part with an approximate acute angle or other similar composite parts.
[0045] It can be understood that the present utility model is described through some embodiments. Those skilled in the art know that without departing from the spirit and scope of the present utility model, various changes or equivalent substitutions can be made to these features and embodiments. Additionally, under the teaching of the present utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present utility model.
Claims
1. A RTM curing molding structure of an elongated L-shaped composite part, characterized in that: The invention comprises a right half mold (1), a left half mold (2) and an upper mold (3); the right half mold (1) is provided with a right cavity (101), the left half mold (2) is provided with a left cavity (201), and the cavity formed by the left half mold (2), the right half mold (1) and the upper mold (3) after being combined is a molding cavity of the part; the upper mold (3) is provided with a plurality of glue injection ports, and the glue injection ports are respectively arranged at the highest point, the lowest point and the four corners according to the shape of the part; the left half mold (2) is provided with a plurality of glue outlets, and the glue outlets are respectively arranged at the lowest point and the left and right lower corners according to the shape of the part.
2. The RTM curing molding structure of an elongated L-shaped composite part according to claim 1, characterized in that: Two guide pins (102) are embedded in the mating surface of the right half mold (1), and the left half mold (2) is positioned by the guide pins (102). Two guide sleeves (103) are embedded in the upper surface of the right half mold (1), and the upper mold (3) is positioned by the guide sleeves (103). A lifting ring (104) is installed on the outer side of the right half mold (1).
3. The RTM curing molding structure of an elongated L-shaped composite part according to claim 2, characterized in that: Two guide sleeves (202) are embedded in the mating surface of the left half mold (2), and the guide sleeves (202) are docked and positioned with the guide pins (102) of the right half mold (1). Two guide sleeves (203) are embedded in the upper surface of the left half mold (2), and the guide sleeves (203) are docked and positioned with the upper mold (3). A drill sleeve (204) is embedded in the position of the process ear piece in the part margin area in the left cavity (201) of the left half mold (2). A sealing groove (201) is provided on the mating surface of the left half mold (2) around the left cavity (201), and a sealing strip (205) is placed in the sealing groove (205). A lifting ring (206) is installed on the outer surface of the left half mold (2).
4. The RTM curing molding structure of an elongated L-shaped composite part according to claim 3, characterized in that: A lifting ring three (301) is installed on the upper mold (3).
5. The RTM curing molding structure of an elongated L-shaped composite part according to claim 4, characterized in that: The upper surface of the left half mold (2) is provided with a second sealing groove surrounding the outer side of the left cavity (201), and the upper surface of the right half mold (1) is provided with a third sealing groove surrounding the outer side of the right cavity (101), and a second sealing strip (8) is placed in the second sealing groove and the third sealing groove.
6. The RTM curing molding structure of an elongated L-shaped composite part according to claim 4, characterized in that: The guide sleeve three (203) of the left half mold (2) and the guide sleeve one (103) of the right half mold (1) are positioned with the upper mold (3) by means of a guide pin two (9) and are connected by means of a hexagonal bolt one (10); a flat washer one (11) and an elastic washer one (12) are provided between the hexagonal bolt one (10) and the upper mold (3).
7. The RTM curing molding structure of an elongated L-shaped composite part according to claim 6, characterized in that: The right half mold (1) and the left half mold (2) are connected by two hexagonal bolts (4) and a hexagonal nut (5), and two flat washers (6) and two elastic washers (7) are arranged between the head of the two hexagonal bolts (4) and the left half mold (2).
8. The RTM curing molding structure of an elongated L-shaped composite part according to claim 3, characterized in that: The drill sleeve (204) is sealed with a plug (13), and a polytetrafluoroethylene gasket (14) is added between the drill sleeve (204) and the plug (13).
9. The RTM curing molding structure of an elongated L-shaped composite part according to claim 1, characterized in that: The multiple glue injection ports of the upper mold (3) and the multiple glue outlet ports of the left half mold (2) are sealed with a second plug (15).