A composite box-shaped structure manufacturing tool and a manufacturing method

Abstract

A kind of composite box type structure preparation tool and preparation method, it is related to composite application technical field.The folding forming material frame includes four frame edges, each frame edge is made of frame bar and two turning connecting rods hingedly installed at its two ends, the outside end of turning connecting rod is fixedly installed connecting rod joint, the hinged point position of turning connecting rod capable of vertical swing is installed turning handle, corresponding two connecting rod joints are connected by double-end universal joint between every two intersecting frame edges, and multiple material piece spring clamps are installed on each frame edge.The frame bar, turning connecting rod and double-end universal joint are combined to form foldable rectangular material frame, the structure is simple, thermoplastic composite sheet is pre-cut simply, and preform can be formed by folding, which is helpful to simplify operation and cost control in batch production process.

Description

Technical Field

[0001] This invention relates to the field of composite material application technology, specifically a tool and method for preparing composite material box-shaped structures. Background Technology

[0002] With the development and application of composite materials, their superior performance has led to their widespread use in high-tech fields such as aviation, aerospace, shipbuilding, and rail transportation. Composite materials possess excellent specific strength and specific stiffness, as well as good corrosion resistance and fatigue resistance. The widespread application of composite materials can effectively reduce structural weight while also extending structural maintenance intervals and service life. This advantage is particularly pronounced in structural areas prone to water accumulation, corrosion, and inconvenient to maintain frequently.

[0003] Box-shaped structures are a common basic component in various fields, such as aircraft wing ribs, and water deflectors and battery boxes in aerospace, shipbuilding, and rail transportation. Traditional box-shaped structures generally use metal structures such as aluminum alloys, which are prone to corrosion problems after long-term use. Therefore, composite material box-shaped structures that can meet the requirements of strength, rigidity, corrosion resistance, light weight, and ease of maintenance are gradually replacing traditional metal box-shaped structures. However, current composite material box-shaped structures are generally made of thermosetting composite materials, and the manufacturing tools and processes are relatively complex, resulting in cumbersome operation and high cost during mass production, which requires further optimization and improvement. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a tool and method for preparing a composite material box-shaped structure. It uses a frame rod, a turning link, and a double-headed universal joint to form a foldable rectangular frame. The structure is simple, and the thermoplastic composite sheet is pre-cut and folded to form a preform, which helps to simplify operations and control costs in the mass production process.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A composite material box-shaped structure manufacturing tool includes a folding molding frame. The folding molding frame includes four rectangular frame sides. Each frame side consists of a frame rod and two hinged connecting rods at both ends of the frame rod. A connecting rod connector is fixedly installed on the outer end of each connecting rod. Two connecting rods at opposite ends of the frame sides can swing horizontally around their hinge points with the frame rod. The other two connecting rods at opposite ends of the frame sides can swing vertically around their hinge points with the frame rod. A turning handle is installed at the hinge point of each vertically swinging connecting rod and the frame rod. The main body of the turning handle is an L-shaped rocker arm, and the end of its bottom support arm is rotatably connected to the hinge point. A handle is provided on the top support arm of the rocker arm. A limiting stop bar is laterally installed on the turning connecting rod at the intersection of the two supports arm. Two connecting rod connectors are connected between each pair of intersecting frame sides by a double-headed universal joint. Multiple material spring clamps with clamping ends facing the inside of the frame side are installed on each frame side.

[0007] A method for preparing a composite material box structure includes the following steps:

[0008] Step 1: According to the load-bearing requirements of the box-shaped structure to be prepared, add the allowance according to the box-shaped unfolded diagram and cut and prepare thermoplastic composite sheet. Cut four straight notches and four oblique notches at the four corners of the thermoplastic composite sheet as turning notches.

[0009] Step 2: Place the thermoplastic composite sheet inside the folding molding frame and clamp and fix the remaining area with multiple sheet spring clips to ensure that the inner edges of the four straight notches and the two sides of the four oblique notches are fixed by the sheet spring clips. Then heat and soften the thermoplastic composite sheet.

[0010] Step 3: Prepare a hot-pressing combination mold, which includes an upper mold and a lower mold. The top of the lower mold is provided with a boss that matches the internal cross-section of the box-shaped structure, and the bottom of the upper mold is provided with a groove that matches the external cross-section of the box-shaped structure.

[0011] Step 4: Lay the softened thermoplastic composite sheet on the top boss of the lower mold. First, press down the four turning handles to bend the two sides of the thermoplastic composite sheet held by the opposite frame edges vertically downward to form two of the box walls. The bending marks are the two straight lines where the four straight notches are located. Then, continue to press the four turning handles. Under the support of the top boss of the lower mold and the tension of the thermoplastic composite sheet, the bottom edge of the box structure is completed by turning the corners. Finally, continue to press the four turning handles to pull the other two sides of the thermoplastic composite sheet held by the opposite frame edges vertically downward to form the remaining two box walls. Finally, the thermoplastic composite sheet is bent to form a preform.

[0012] Step 5: Press the preform together by the bottom groove of the upper mold and the top boss of the lower mold. The hot press combination mold is installed on the hot press for preheating. Then, the hot press is used to close the mold and apply pressure to remove the internal pores of the preform.

[0013] Step 6: Demold the preform after hot pressing and allow it to cool naturally at room temperature;

[0014] Step 7: Machining is performed according to the designed external dimensions to obtain the box-shaped structure.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a frame rod, a turning link and a double-headed universal joint to form a foldable rectangular frame, and uses a spring clip to clamp and fix the thermoplastic composite material sheet. The structure is simple and the operation is convenient. The thermoplastic composite material sheet is pre-cut and can be formed into a box-shaped preform by simple folding with the help of a hot-pressing combination mold. The bottom edge of the preform forms an inner hidden flange corner during the folding process, which can eliminate the influence of excess material and help to reinforce the bottom edge. Then, the required composite material box-shaped structure is formed by hot pressing and curing. The manufacturing difficulty is low, which helps to simplify the operation and control costs in the mass production process, and has a wide range of applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the box-shaped structure prepared by the present invention;

[0017] Figure 2 This is a schematic diagram of the cutting of the thermoplastic composite material sheet used in the preparation of this invention;

[0018] Figure 3 This is an overall structural diagram of the folded molding frame used in the preparation of this invention;

[0019] Figure 4 yes Figure 3 A magnified view of a portion of the image;

[0020] Figure 5 This is an assembly diagram of the thermoplastic composite sheet and the folded molding frame during the preparation of this invention;

[0021] Figure 6 This is a diagram showing the state of the folded molding frame undergoing one box wall bending during the preparation of this invention;

[0022] Figure 7 yes Figure 6 A magnified view of a portion of the image;

[0023] Figure 8 This is a diagram showing the state of the folded molding frame being bent and folded at the corners during the preparation of this invention.

[0024] Figure 9 yes Figure 8 A magnified view of a portion of the image;

[0025] Figure 10 This is a diagram showing the state of the folded molding frame undergoing secondary box wall bending during the preparation of this invention;

[0026] Figure 11 yes Figure 10 A magnified view of a portion of the image;

[0027] Figure 12 This is an assembly diagram of the preform and the hot-pressing combination mold used in the preparation of this invention.

[0028] In the diagram: 1-Box-shaped structure, 2-Thermoplastic composite sheet, 2.1-Straight notch, 2.2-Angled notch, 3-Folded forming frame, 3.1-Frame rod, 3.2-Turn connecting rod, 3.3-Connecting rod joint, 3.4-Double-headed universal joint, 3.5-Turn crank handle, 3.6-Sheet spring clip, 3.5.1-Rock arm, 3.5.2-Handle, 3.5.3-Limit stop bar, 4.1-Upper mold, 4.2-Lower mold, 5-Preform. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] like Figures 3-4As shown, a composite material box-shaped structure manufacturing tool includes a folding molding frame 3. The folding molding frame 3 includes four rectangularly arranged frame sides. Each frame side consists of a frame rod 3.1 and two hinged connecting rods 3.2 hinged to both ends of the frame rod 3.1. The frame rod 3.1 is preferably an adjustable telescopic rod to facilitate the adaptation and adjustment of the size of the folding molding frame 3, meeting the clamping and fixing requirements of thermoplastic composite material sheets 2 of different sizes. A connecting rod joint 3.3 is fixedly installed on the outer end of each hinge connecting rod 3.2. Two of the hinge connecting rods 3.2 opposite to the ends of the frame sides can swing horizontally around their hinge points with the frame rod 3.1, and the other two hinge connecting rods 3.2 opposite to the ends of the frame sides can swing vertically around their hinge points with the frame rod 3.1. A hinge handle 3.5 is installed at the hinge point position of each vertically swinging hinge connecting rod 3.2 and the frame rod 3.1. The main body of the turning handle 3.5 is an L-shaped rocker arm 3.5.1, with its bottom support arm rotatably connected to a hinge point. A handle 3.5.2 is provided on the top support arm of the rocker arm 3.5.1. A limiting stop bar 3.5.3 is laterally positioned at the intersection of the two supports and is press-fitted onto the turning connecting rod 3.2. Two corresponding connecting rod joints 3.3 are connected between each pair of intersecting frame edges via a double-headed universal joint 3.4. Multiple sheet spring clips 3.6 with their clamping ends facing inwards are installed on each frame edge. The number of sheet spring clips 3.6 is selected as needed to ensure tension and flatness when clamping the thermoplastic composite sheet 2.

[0031] like Figures 1-12 As shown, a method for preparing a composite material box structure includes the following steps:

[0032] Step 1: According to the load-bearing requirements of the box-shaped structure 1 to be prepared, the thermoplastic composite sheet 2 is prepared by adding an allowance according to the box-shaped unfolding diagram and cutting the material. The allowance should be 30mm to 50mm. Four straight notches 2.1 and four oblique notches 2.2 are pre-cut at the four corners of the thermoplastic composite sheet 2 as turning notches. To meet the load-bearing requirements, carbon fiber material can be used to reinforce the thermoplastic composite sheet 2 during the layup preparation stage.

[0033] Step 2: Place the thermoplastic composite sheet 2 inside the folding and forming frame 3 and clamp and fix the remaining area with multiple sheet spring clips 3.6 to ensure that the inner edges of the four straight notches 2.1 and the two side edges of the four oblique notches 2.2 are fixed by the sheet spring clips 3.6. Then, put the folding and forming frame 3 into an infrared heating box to heat and soften the thermoplastic composite sheet 2. The heating and softening temperature range is within 400℃ and can be selected as needed.

[0034] Step 3: Prepare the hot pressing combination mold, which includes an upper mold 4.1 and a lower mold 4.2. It can be machined from high-temperature resistant alloy steel. The lower mold 4.2 has a boss at the top that matches the internal cross section of the box structure 1, and the upper mold 4.1 has a groove at the bottom that matches the external cross section of the box structure 1.

[0035] Step 4: Lay the softened thermoplastic composite sheet 2 on the top boss of the lower mold 4.2. First, press down the four turning handles 3.5 to vertically bend the two sides of the thermoplastic composite sheet 2 held by the opposite frame edges downwards to form two box walls. The bending marks are the two straight lines where the four straight notches 2.1 are located. Then, continue to press down the four turning handles 3.5. Under the support of the top boss of the lower mold 4.2 and the tension of the thermoplastic composite sheet 2, the two turning connecting rods 3.2 at the four corners of the folded frame 3 are respectively rotated around the corresponding double-headed universal joints. Section 3.4 rotates to form a V-shaped structure to achieve elbow bending. The four oblique notches 2.2 and the spring clips on both sides of the material sheet 3.6 move accordingly to fold the thermoplastic composite material sheet 2 in a Z-shape at the corresponding position, completing the folded corner of the bottom edge of the box structure 1. Finally, continue to press the four turning handles 3.5 until the two turning connecting rods 3.2 of the four corners of the folded and formed material frame 3 are attached and positioned. Pull the other two opposite frame edges to bend the thermoplastic composite material sheet 2 vertically downward to form the remaining two box walls. Finally, the thermoplastic composite material sheet 2 is bent to form the preform 5.

[0036] Step 5: Press the preform 5 together by the bottom groove of the upper mold 4.1 and the top boss of the lower mold 4.2. The hot pressing combination mold is installed on the hot press for preheating at a temperature of 200-230°C. Then, the hot pressing combination mold is closed and pressurized by the hot press until the set pressure is reached to ensure that the pressure of the preform 5 is not less than 2MPa and to eliminate the internal pores of the preform 5.

[0037] Step 6: Demold the preform 5 after hot pressing and allow it to cool naturally at room temperature;

[0038] Step 7: Machining is performed according to the designed external dimensions to prepare the box-shaped structure 1.

[0039] Among them, the hot pressing combination mold can be further optimized. The upper mold 4.1 can be set with a draft angle or a split combination mold structure can be adopted to ensure pressure transmission while facilitating demolding. The four corners of the boss of the lower mold 4.2 are pre-made with mold recesses that match the flange corners of the bottom edge of the box structure 1 to ensure that the final surface of the box structure 1 is smooth.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] 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 tool for fabricating a composite material box-shaped structure, characterized in that: The folding molding frame (3) includes four rectangular frame edges. Each frame edge consists of a frame rod (3.1) and two pivoting connecting rods (3.2) hinged to both ends of the frame rod (3.1). A connecting rod connector (3.3) is fixedly installed on the outer end of each pivoting connecting rod (3.2). The two pivoting connecting rods (3.2) at opposite ends of the frame edges can swing horizontally around the hinge point with the frame rod (3.1). The other two pivoting connecting rods (3.2) at opposite ends of the frame edges can swing vertically around the hinge point with the frame rod (3.1). Each pivoting connecting rod (3.2) capable of vertical swinging... 2) A turning handle (3.5) is installed at the hinge point of the frame rod (3.1). The main body of the turning handle (3.5) is an L-shaped rocker arm (3.5.1) and the end of its bottom support arm is rotatably connected to the hinge point. The top support arm of the rocker arm (3.5.1) is provided with a handle (3.5.2). The rocker arm (3.5.1) is located at the intersection of the two arms and a limiting stop bar (3.5.3) is set on the turning connecting rod (3.2). The two corresponding connecting rod joints (3.3) are connected between each two intersecting frame edges through a double-headed universal joint (3.4). Multiple material spring clips (3.6) with clamping ends facing the inside of the frame edge are installed on each frame edge.

2. The composite material box-shaped structure fabrication tool according to claim 1, characterized in that: All the frame rods (3.1) are telescopic rods.

3. A method for preparing a composite material box structure, characterized in that: According to the preparation tool described in claim 1, the method for preparing a composite material box structure includes the following steps: Step 1: According to the load-bearing requirements of the box structure (1) to be prepared, add the allowance according to the box unfolding diagram and cut the material to prepare thermoplastic composite sheet (2). Cut four straight notches (2.1) and four oblique notches (2.2) at the four corners of the thermoplastic composite sheet (2) as turning notches. Step 2: Place the thermoplastic composite sheet (2) inside the folding molding frame (3) and clamp and fix the remaining area with multiple sheet spring clips (3.6) to ensure that the inner edge of the four straight notches (2.1) and the two sides of the four oblique notches (2.2) are fixed by the sheet spring clips (3.6). Then heat and soften the thermoplastic composite sheet (2). Step 3: Prepare a hot pressing combination mold, which includes an upper mold (4.1) and a lower mold (4.2). The lower mold (4.2) has a boss at the top that matches the internal cross section of the box structure (1), and the upper mold (4.1) has a groove at the bottom that matches the external cross section of the box structure (1). Step 4: Lay the softened thermoplastic composite sheet (2) on the top boss of the lower mold (4.2). First, press down the four turning handles (3.5) to make the two sides of the thermoplastic composite sheet (2) held by the opposite frame edges bend vertically downward to form two of the box walls. The bending marks are the two straight lines where the four straight notches (2.1) are located. Then, continue to press down the four turning handles (3.5). Under the support of the top boss of the lower mold (4.2) and the tension of the thermoplastic composite sheet (2), the bottom edge of the box structure (1) is completed with the corner flap. Finally, continue to press down the four turning handles (3.5) to pull the other two sides of the thermoplastic composite sheet (2) held by the opposite frame edges to bend vertically downward to form the remaining two box walls. Finally, the thermoplastic composite sheet (2) is bent to form the preform (5). Step 5: Press the preform (5) together with the bottom groove of the upper mold (4.1) and the top boss of the lower mold (4.2). The hot press combination mold is installed on the hot press for preheating. Then, the hot press is used to close the hot press combination mold and press it to remove the internal pores of the preform (5). Step 6: Demold the preform (5) after hot pressing and allow it to cool naturally at room temperature; Step 7: Machining is performed according to the designed external dimensions to prepare the box-shaped structure (1).

4. The method for preparing a composite material box structure according to claim 3, characterized in that: The allowance in step one is 30mm to 50mm.

5. The method for preparing a composite material box structure according to claim 3, characterized in that: The upper mold (4.1) is provided with a draft angle or adopts a split-combination mold structure.

6. The method for preparing a composite material box structure according to claim 3, characterized in that: The lower mold (4.2) has mold recesses at the four corners of the boss that match the flange corners of the bottom edge of the box structure (1).

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