A hot diaphragm forming die for composite parts

Abstract

This utility model discloses a heat insulation film molding die for composite material parts, including a die body with a two-stage stepped structure. The upper stepped surface of the die body has a first model-attaching surface, and the lower stepped surface of the die body has a second model-attaching surface. Positioning bosses are provided at both ends of the first and second model-attaching surfaces, and positioning grooves are provided on the positioning bosses. In this utility model, the die is an integral structure. By setting two model-attaching surfaces on the die and providing positioning bosses at both ends of the first and second model-attaching surfaces, the positioning grooves on the positioning bosses can match the lugs of the pre-formed sheet, achieving precise positioning of the sheet and the die. This utility model uses a single die for two transfers combined with heat insulation film pre-forming technology to achieve precise preparation of Z-shaped part preforms, significantly improving the part forming quality and effectively reducing tooling costs.

Description

Technical Field

[0001] This utility model relates to the field of aerospace parts manufacturing, specifically to a thermal insulation film molding die for composite material parts. Background Technology

[0002] In the structural design of modern commercial aircraft fuselages, Z-shaped composite material parts are widely used as fuselage reinforcement and connecting components in fuselage panels. As key supporting and reinforcing components on the fuselage panels, their manufacturing process directly affects the safety and reliability of the overall fuselage structure.

[0003] In composite material manufacturing, the "automatic layup + thermal insulation process" is widely used as an automated process for manufacturing C-shaped, L-shaped, and Z-shaped composite material structural parts. When traditional Z-shaped composite material parts are pre-formed using a single "automatic layup + thermal insulation process," the molding quality mainly depends on the resin flow and fiber slippage, making process control more difficult than for C-shaped and L-shaped composite material parts. Particularly in the inner and outer radius (R-corner) areas of Z-shaped composite material parts, mutual constraints during pre-forming can easily restrict fiber slippage, leading to dimensional deviations and fiber wrinkling in the R-corner areas, affecting the part's yield. Furthermore, the complex shape of the unfolded sheet of Z-shaped composite material parts means that if high-precision positioning with the mold cannot be achieved, the final molded part will exhibit increased fiber angle deviations and severe R-corner wrinkling, resulting in defective parts. Therefore, it is necessary to design a thermal insulation molding mold for composite material parts. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a molding die for thermal insulation film forming of composite material parts.

[0005] The technical solution of this utility model: A mold for forming a thermal insulation film for composite material parts, comprising a mold body, The mold body has a two-stage stepped structure. The upper stepped surface of the mold body has a first model-attaching surface, and the lower stepped surface of the mold body has a second model-attaching surface. The two ends of the first and second model-attaching surfaces are respectively provided with positioning bosses, and the positioning bosses are provided with positioning grooves. The two positioning grooves on the first model surface are used for the initial positioning of the thermal insulation film forming; The two positioning grooves on the second model surface are used for positioning during the second heat insulation film forming.

[0006] Furthermore, two positioning grooves on the second model surface are used to position the L-shaped preform formed by the first thermal insulation film after being rotated 180°.

[0007] Furthermore, two process reference detection holes are respectively provided on the two positioning bosses of the first model surface.

[0008] Furthermore, the bottom of the mold body is provided with a groove.

[0009] Furthermore, the mold body has a part blank line on one side of the first model surface.

[0010] Furthermore, the mold body has part edge lines and part allowance lines on one side of the second model surface.

[0011] The beneficial effects of this utility model are: In this utility model, the mold is an integral structure. By setting two model-attaching surfaces on the mold, positioning bosses are set at both ends of the first and second model-attaching surfaces, and positioning grooves are set on the positioning bosses to match the ear pieces of the pre-formed material sheet, thus achieving precise positioning of the material sheet and the mold. The mold body is equipped with part blank lines, part edge lines, and part allowance lines to assist in the pre-forming of the heat insulation film of the part; a groove is provided below the mold to enable the mold to be transferred at the work station.

[0012] This invention employs a single mold with two transfers combined with thermal insulation film preforming technology to achieve precise preparation of Z-shaped part preforms. This technical solution is easy to operate and can complete two independent preforming operations without the need for matching other molds. It not only significantly improves the part forming quality but also effectively reduces tooling costs. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the composite material part heat insulation film molding die of this utility model; Figure 2 This is a schematic diagram of the model surface and engraving lines on the mold; Figure 3 This is a schematic diagram of the first model surface on the mold and the blank line of the part; Figure 4 This is another structural schematic diagram of the heat insulation film forming mold for composite material parts of this utility model; Figure 5 This is a schematic diagram of the structure of the preformed sheet; Figure 6 This is a schematic diagram of the first thermal diaphragm molding process; Figure 7 This is a schematic diagram of the L-shaped precast body flipping process; Figure 8 This is a schematic diagram of the second thermal diaphragm forming process; In the diagram: 1. Mold body; 2. Positioning boss; 3. Process datum inspection hole; 4. Positioning groove; 5. First model surface; 6. Part blank line; 7. Second model surface; 8. Part edge line; 9. Part allowance line; 10. Groove; 100. Preformed sheet; 101. Positioning ear; 102. Part film surface; 103. Part bag surface. Detailed Implementation

[0014] The present invention can be further described through the following embodiments; however, the scope of the present invention is not limited to the following embodiments. It should be understood that the embodiments described herein are disclosed by way of illustration only, and the present invention is not intended to limit its scope to the details of the construction and arrangement of the components described below or illustrated in the figures. Furthermore, in describing preferred embodiments, specific terminology will be used for clarity. It should be understood that each specific term includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

[0015] Example 1: Please refer to Figures 1 to 4 As shown, a composite material part heat insulation film molding die includes a mold body 1, which can be machined from aluminum alloy, wood, or PMI foam. The mold body 1 is designed with two mold surfaces according to different molding areas of the part. The mold body 1 has a two-stage stepped structure. The upper stepped surface of the mold body 1 is provided with a first mold surface 5; the lower stepped surface of the mold body 1 is provided with a second mold surface 7. The surface accuracy of the first mold surface 5 and the second mold surface 7 is ±0.25mm, and the surface roughness is not greater than Ra1.6. The two ends of the first mold surface 5 and the second mold surface 7 are respectively provided with positioning bosses 2, and the positioning bosses are provided with positioning grooves 4. The positioning grooves 4 are rectangular grooves of 40mm×40mm. The two positioning grooves 4 on the first model surface 5 are used for the positioning of the first heat insulation film forming; The two positioning grooves 4 on the second model surface 7 are used for positioning during the second thermal insulation film forming.

[0016] More specifically, the two positioning grooves 4 on the second model surface 7 are used to position the L-shaped preform formed by the first thermal insulation film after being rotated 180°.

[0017] In one embodiment, two process reference detection holes 3 are respectively provided on the two positioning bosses 2 of the first model surface 5, which can facilitate subsequent tooling measurement and inspection. The process reference detection holes 3 adopt a φ8H6 tolerance design to ensure the high-precision positioning requirements during tooling inspection.

[0018] In one embodiment, the bottom of the mold body 1 is provided with a groove 10, which can be used for the transfer of the mold between various process stations, such as... Figure 4 As shown.

[0019] In one embodiment, the mold body 1 has a part blank line 6 on one side of the first model surface 5.

[0020] In one embodiment, the mold body 1 is provided with part edge line 8 and part allowance line 9 on one side of the second model surface 7. The part blank line 6, part edge line 8 and allowance line 9 are engraved with a depth of 0.3mm and a width of 0.3mm, and the engraving accuracy is controlled within ±0.25mm.

[0021] Please see Figures 5 to 8 As shown, the molding process of this utility model is as follows: S1. Preparation of preformed sheet 100: A lower non-porous release film is pre-laid on an automatic tape-laying adsorption platform, then a prepreg sheet is laid on the non-porous release film, and then an upper non-porous release film is laid on the surface of the prepreg sheet. Preferably, the coverage area of ​​the upper non-porous release film exceeds that of the prepreg layer and the lower non-porous release film, so that the upper non-porous release film is vacuum-compressed by the platform to prevent material lifting during ultrasonic cutting; then, ultrasonic cutting is performed by the tape-laying machine cutting head to obtain a preformed sheet 100 with a square positioning ear 101 that matches the positioning groove 4 (e.g., ...). Figure 5 (as shown) S2. Preparation for the first heat insulation film molding: Beforehand, lay a layer of polytetrafluoroethylene cloth or apply a release agent on the heat insulation film molding mold of the composite material parts to facilitate demolding of the parts; The preformed sheet 100 is transferred to the first molded surface 5 with the part bag surface 103 facing down and the part molded surface 102 facing up. The positioning ear piece 101 is matched with the positioning groove 4 on the positioning boss at both ends of the first molded surface 5 to achieve precise positioning of the preformed sheet 100 and the composite material part heat insulation film forming mold. S3. Set the vacuum control and temperature control parameters for thermal insulation film forming: S4. First Thermal Insulator Molding: Start the thermal insulation machine. The diaphragm system on the thermal insulation film seals and wraps the preformed sheet 100 and the composite material part thermal insulation molding die. The first thermal insulation molding is performed according to the set vacuum and temperature control parameters. During the molding process, the diaphragm gradually shapes the preformed sheet 100 into an L-shaped structure. After cooling to room temperature, the L-shaped preform is removed (e.g., ...). Figure 6 and 7 (as shown) S5. Second heat insulation film forming preparation: Flip the L-shaped preform horizontally 180° so that the part film-attached side 102 faces down and the part bag-attached side 103 faces up (e.g., Figure 7 and Figure 8 (As shown); by matching the positioning ear 101 with the positioning groove 4 on the positioning boss at both ends of the second model surface 7, the precise positioning of the L-shaped preform and the composite material part heat insulation film forming mold is achieved. S6. Second heat-insulating film forming: Following the set vacuum and temperature control parameters, the second heat-insulating film forming process is performed. Under the pressure of the diaphragm, the L-shaped preform completely adheres to the mold surface to form a Z-shaped structure. After cooling to room temperature, it is removed to obtain the final product (e.g., ...). Figure 8 (As shown).

[0022] In one embodiment, step S2 further includes: laying a breathable felt on the composite material part thermal insulation film molding die to wrap the sharp edges of the non-working area to prevent them from puncturing the vacuum diaphragm, while facilitating the formation of a vacuum environment during pre-forming and improving the molding quality.

[0023] In one embodiment, in step S3, vacuum control employs a three-stage vacuuming strategy to ensure orderly gas discharge while preventing fiber displacement and achieving material forming. The initial stage involves increasing the pressure from 1 to 2 kPa / min to 5 to 6 kPa; the transition stage involves increasing the pressure from 3 to 4 kPa / min to 30 to 36 kPa; and the final stage involves increasing the pressure from 5 to 6 kPa / min to 72 to 78 kPa. To avoid poor temperature uniformity of parts due to excessively high heating rates and excessively long heating times due to excessively low heating rates, the temperature control is as follows: during the heating stage, the temperature is increased to 75~85℃ at a rate of 1~5℃ / min; during the holding stage, the temperature is held for 30±6min after the heating is completed; during the cooling stage, the temperature is cooled to room temperature at a rate of ≤5℃ / min after the holding stage is completed.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0025] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A molding die for forming a thermal insulation film on a composite material part, comprising a mold body (1), characterized in that, The mold body (1) has a two-stage stepped structure. The upper stepped surface of the mold body (1) is provided with a first model-attaching surface (5), and the lower stepped surface of the mold body (1) is provided with a second model-attaching surface (7). The first model-attaching surface (5) and the second model-attaching surface (7) are respectively provided with positioning bosses (2), and positioning grooves (4) are provided on the positioning bosses. The two positioning grooves (4) on the first model surface (5) are used for the first positioning of the thermal insulation film forming; The two positioning grooves (4) on the second model surface (7) are used for positioning the second thermal insulation film forming.

2. The composite material part heat insulation film forming mold according to claim 1, characterized in that, The two positioning grooves (4) on the second model surface (7) are used to position the L-shaped preform formed by the first thermal insulation film after being rotated 180°.

3. The composite material part heat insulation film forming mold according to claim 1, characterized in that, Two process reference detection holes (3) are respectively provided on the two positioning bosses (2) of the first model surface (5).

4. The composite material part heat insulation film forming mold according to claim 1, characterized in that, The bottom of the mold body (1) is provided with a groove (10).

5. The composite material part heat insulation film forming mold according to claim 1, characterized in that, The mold body (1) has a part blank line (6) on one side of the first model surface (5).

6. The composite material part heat insulation film forming mold according to claim 1, characterized in that, The mold body (1) has part edge lines (8) and part allowance lines (9) on one side of the second model surface (7).

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