Forming die and preparation method of composite cylinder with special-shaped structure

Abstract

The invention relates to a forming die and a preparation method of a composite cylinder with a special-shaped structure, and belongs to the field of machining of composite cylinders with flanging structures. The die comprises an upper pressing tool, a lower pressing tool, a front pressing disc and a rear pressing disc. The upper press is provided with a concave smooth semi-cylindrical surface, and the lower press is provided with a convex smooth semi-cylindrical surface. Combined fastening between the dies is achieved through the pins, the position of the carbon fiber reinforced epoxy resin plain woven fabric composite prepreg laid in the dies is fixed, and a composite barrel with a flange is integrally formed conveniently; the front pressing disc and the rear pressing disc are connected with the upper pressing tool through single-head connecting bolts on the two sides, it is guaranteed that the carbon fiber reinforced epoxy resin plain woven fabric composite material prepreg is attached to the semi-cylindrical face of the clamp, and positioning of the composite material barrel with the turned-over edge is achieved; the wall thickness size of the composite material barrel with the flanging structure is adjusted and controlled by adjusting the wall thickness of the backward extrusion barrel-shaped part; and the machining allowance of the wheel blank is reduced by adopting a compound process of backward extrusion and set size and laying range.

Description

Technical Field

[0001] The invention belongs to the technical field of processing a composite material barrel with a special-shaped structure, and in particular relates to a forming die and a preparation method of a composite material barrel with a special-shaped structure. Background Art

[0002] At present, domestic and foreign universities and research institutes have developed a number of in-situ mechanical loading CT devices. These devices usually require the design of independent loading equipment, and cooperate with the radiation source through a turntable to achieve 360° all-round projection data acquisition. However, due to the limitations of the turntable space and its coordination with the radiation source, the design space of the device is subject to certain constraints, resulting in the inability to use conventional in-situ mechanical characterization devices. In addition, in-situ loading devices usually use low-absorption materials such as aluminum alloy and plexiglass as radiation transmission windows. However, the transmission window must not only meet the requirements of radiation transmission, but also bear the load-bearing function together with the load-bearing cylinder. How to effectively improve the load-bearing capacity of the mechanical in-situ loading device while ensuring high radiation transmittance is an urgent problem to be solved.

[0003] The support device of the mechanical testing machine will produce certain obstructions during the X-ray penetration process, resulting in the superposition of mixed noise and sample information in the collected projection data, which brings great difficulties to the data reconstruction process. The penetration of X-rays in composite tubes is better than that of aluminum alloy materials, and its load-bearing capacity is better than that of PMMA materials. Therefore, composite materials can be used to make high-load and high-penetration support devices. The composite tube structure is easy to prepare, but the preparation of composite tubes with special-shaped flanging structures is more difficult. The preparation method of the special-shaped composite tube adopted is to prepare the tube and the special-shaped flanging separately, and then use adhesive to bond and form. Due to the gap between the preparation precision contact surface and the installation of the cylinder and the special-shaped flanging structure, the shear strength provided by the adhesive bonding is relied on. Under external loads, the cylinder and the special-shaped flanging structure are prone to debonding and damage. Therefore, it is necessary to design an integrated molding mold for preparing a special-shaped composite tube with a flanging structure. Summary of the invention

[0004] In order to solve the problems of difficulty in forming a composite material tube with a special structure, complex process, high cost and low production efficiency, the purpose of the present invention is to provide a forming mold and preparation method of a composite material tube with a special structure, which can realize the integrated forming of the composite material tube with a special structure, reduce the difficulty and process complexity of preparing the composite material tube with a special structure, and improve the axial and radial mechanical properties of the composite material tube, and improve the bearing capacity of the composite material tube with a special structure. The present invention also has the advantages of high preparation efficiency, high precision, low pollution and reduced processing cost.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The present invention discloses a forming die for a composite material cylinder with a special structure, comprising an upper press, a lower press, a front pressure plate, and a rear pressure plate. The upper press, the lower press, the front pressure plate, and the rear pressure plate all have through holes, and are assembled and fastened by screws, thereby achieving a fixed position for the plain-woven fabric composite material prepreg laid therein, and facilitating the integrated molding of a special-shaped composite material cylinder. The upper press has an inner concave smooth semi-cylindrical surface, and the lower press has an outer convex smooth semi-cylindrical surface. The front pressure plate and the rear pressure plate are connected to the upper press by single-head connecting bolts on both sides, ensuring that the plain-woven fabric composite material prepreg fits the semi-cylindrical surface of the fixture, thereby achieving positioning of the special-shaped composite material cylinder, and by adjusting the positioning position of the special-shaped composite material cylinder to match, special-shaped composite material cylinders of different thicknesses can be manufactured.

[0007] Preferably, the upper pressing tool adopts an outer semicircular concave mold, one end of the outer semicircular concave mold is concave, and its concave side is adapted to the shape of the convex side of the inner semicircular cylindrical boss mold with a semi-cylinder attached. The lower pressing tool adopts an inner semicircular cylindrical boss mold, one end of the inner semicircular cylindrical boss mold is convex, and the inner side of the convexity is adapted to the inner surface of the outer semicircular concave mold. Circular through holes are distributed on both sides of the inner semicircular cylindrical boss mold and the outer semicircular concave mold. The circular through holes are used to connect and fix the outer semicircular concave mold with the inner cylindrical mold, and are closed and connected with the inner semicircular cylindrical boss mold positioning column through the corresponding outer semicircular concave mold positioning groove. The front pressure plate and the rear pressure plate respectively adopt two front and rear positioning chucks, which are two identical fixing plates with inner convex structures. Circular through holes are processed on the plates, and the circular through holes cooperate with the outer semicircular concave mold. After the outer semicircular concave mold and the inner semicircular cylindrical boss mold are clamped, positioning chucks are used to connect them at both ends to position and tighten the upper press, the lower press, the front pressure plate and the rear pressure plate.

[0008] As a further preferred embodiment, the inner semi-cylindrical boss mold and the outer semi-circular recessed mold are both made of steel. The positioning chucks are two identical steel plates with inner convex structures.

[0009] The invention also discloses a forming and preparing method for a special-shaped structure composite material cylinder, which is realized based on a forming die of the special-shaped structure composite material cylinder.

[0010] A forming and preparation method of a composite material tube with a special-shaped structure comprises the following steps:

[0011] Step 1, cutting the plain fabric composite material prepreg into rectangles of predetermined size by a wire cutting machine;

[0012] Step 2: Use an appropriate amount of acetone to clean the inner surfaces of the upper pressing tool and the lower pressing tool of the fixture for preparing the special-shaped composite material tube;

[0013] Step 3: Lay the pretreated plain fabric composite material slices in sequence on the middle surface of the cleaned upper press, and use a roller to scrape out the air between each layer of prepreg to keep the surface flat;

[0014] Step 4: Lay the pretreated plain fabric composite material slices in sequence on the pillow-shaped surfaces on both sides of the cleaned upper press, and use a roller to scrape out the air between each layer of prepreg, and keep the surface of each layer of prepreg flat and keep good and stable contact with the connection with the middle surface of the upper press;

[0015] Step 5, compact the lower pressing tool and the upper pressing tool to ensure that there is no gap between the plain fabric composite materials, and at the same time, use the pressing plates on both sides to flatten and compact the left and right sides;

[0016] Step 6: Use screws to fix the upper press, the lower press and the pressure plates on both sides to ensure the stability of the overall fixture and that the composite material cylinder with the special-shaped structure does not deform during the curing process. A total of 16 screws are used for fastening.

[0017] Step 7, tighten the screws of the combined mold longitudinally and transversely and place the mold in a heating box for semi-curing;

[0018] Step 8, taking the semi-cured combined mold out of the heating box, tightening the screws again and placing it in the heating box again for secondary curing; the combined mold is the forming mold of the special-shaped composite material cylinder.

[0019] Step 9: Take out the fully cured combined mold from the heating box, cool it to room temperature, take out the special-shaped composite material mold, and grind the end face of the obtained processed specimen to obtain a high-precision composite material special-shaped structure cylinder.

[0020] Preferably, in step 6, 16 screws are used for fastening, wherein the upper pressing tool and the lower pressing tool are fastened with 3 screws on each horizontal side, so as to ensure that the longitudinal displacement of the special-shaped structure cylinder is stable and does not slide during the heating process, and the front and rear pressing plates are fastened with the upper pressing tool with 5 screws each, so as to ensure that the lateral displacement of the special-shaped structure cylinder is stable and does not slide during the heating process;

[0021] Preferably, in step 7, the semi-curing temperature is 80° C. and the curing time is 1 hour.

[0022] Preferably, in step 8, the secondary curing temperature is 125° C. and the curing time is 2 hours.

[0023] Beneficial effects:

[0024] 1. The present invention discloses a forming mold and a preparation method for a composite material cylinder of a special structure. The upper pressing tool adopts an outer semicircular concave mold, one end of which is concave, and the concave side thereof is adapted to the shape of the convex side of the inner semicircular cylindrical boss mold with a semi-cylinder attached thereto. The lower pressing tool adopts an inner semicircular cylindrical boss mold, one end of which is convex, and the inner side of the convexity is adapted to the inner surface of the outer semicircular concave mold with a cavity. Circular through holes are distributed on both sides of the inner semicircular cylindrical boss mold and the outer semicircular concave mold. The circular through holes are used to connect and fix the outer semicircular concave mold and the inner cylindrical mold, and are closed and connected with the positioning column of the inner semicircular cylindrical boss mold through the corresponding positioning groove of the outer semicircular concave mold. The upper press, the lower press, the front pressure plate and the rear pressure plate all have through holes, and the upper press, the lower press, the front pressure plate and the rear pressure plate are combined and fastened by screws, thereby achieving the fixed position of the plain fabric composite material prepreg laid therein, which is convenient for the integrated molding of the special-shaped composite material cylinder.

[0025] 2. The present invention discloses a forming mold and preparation method for a special-shaped composite material cylinder, wherein a front pressure plate and a rear pressure plate are connected to an upper pressing tool via single-head connecting bolts on both sides to ensure that the plain fabric composite material prepreg fits the semi-cylindrical surface of the fixture, thereby realizing positioning of the special-shaped composite material cylinder. Special-shaped composite material cylinders of different thicknesses can be manufactured by adjusting the positioning position of the special-shaped composite material cylinder.

[0026] 3. The present invention discloses a forming die and preparation method for a composite material cylinder with a special structure, which can realize the forming preparation of difficult-to-process complex special structures. The composite material cylinder with an integrated molding special shape can avoid the local debonding between the cylinder and the special-shaped flange under the action of axial pressure, which leads to local damage, end warping and cracking.

[0027] 4. The present invention discloses a forming mold and a preparation method for a special-shaped composite material cylinder. The integrated special-shaped composite material cylinder can improve the axial and radial mechanical properties of the composite material cylinder and improve the load-bearing capacity of the special-shaped composite material cylinder.

[0028] 5. The present invention discloses a forming die and a preparation method for a special-shaped composite material cylinder, which adopts a composite process of reverse extrusion and set size and laying range to reduce the processing allowance of the wheel blank.

[0029] 6. The present invention discloses a forming die and a preparation method for a composite material cylinder with a special structure. The wall thickness of the composite material cylinder with a special structure is regulated by adjusting the wall thickness of the reverse extruded cylindrical part, thereby reducing the processing amount and further improving the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an overall schematic diagram of the 3D model of the clamp of the present invention;

[0031] Figure 2 A top view of the upper pressing tool of the clamp of the present invention;

[0032] Figure 3 It is a front view of the upper pressing tool of the clamp of the present invention;

[0033] Figure 4 A side view of an upper pressing tool of the clamp of the present invention;

[0034] Figure 5 A top view of the lower pressing tool of the clamp of the present invention;

[0035] Figure 6 It is a front view of the lower pressing tool of the clamp of the present invention;

[0036] Figure 7 A side view of the lower pressing tool of the clamp of the present invention;

[0037] Figure 8 A top view of the front pressure plate of the clamp of the present invention;

[0038] Fig. 9 It is a front view of the front pressure plate of the clamp of the present invention;

[0039] Fig.10 A side view of the front pressure plate of the clamp of the present invention;

[0040] Fig.11 A top view of the rear pressure plate of the clamp of the present invention;

[0041] Fig.12 It is a front view of the rear pressure plate of the clamp of the present invention;

[0042] Fig.13 It is a side view of the rear pressure plate of the clamp of the present invention;

[0043] Among them: 1—upper pressure tool, 2—lower pressure tool, 3—front pressure plate, 4—rear pressure plate. DETAILED DESCRIPTION

[0044] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0045] like Figure 1As shown, this embodiment discloses a forming die of a composite material cylinder of a special structure disclosed by the present invention, including an upper press 1, a lower press 2, a front pressure plate 3, and a rear pressure plate 4. The upper press 1, the lower press 2, the front pressure plate 3, and the rear pressure plate 4 all have through holes, and are combined and fastened by screws to realize the fixing position of the plain fabric composite material prepreg laid therein, so as to facilitate the integrated molding of a special-shaped composite material cylinder. The upper press 1 has an inner concave smooth semi-cylindrical surface, and the lower press 2 has an outer convex smooth semi-cylindrical surface. The front pressure plate 3 and the rear pressure plate 4 are connected to the upper press 1 by single-head connecting bolts on both sides to ensure that the plain fabric composite material prepreg fits the semi-cylindrical surface of the fixture, so as to realize the positioning of the special-shaped composite material cylinder, and the special-shaped composite material cylinder of different thicknesses can be made by adjusting the positioning position matching of the special-shaped composite material cylinder. The inner semi-cylindrical boss mold and the outer semi-circular concave mold are both made of steel.

[0046] The upper pressing tool 1 adopts an outer semicircular concave mold, one end of which is concave, and its concave side is adapted to the shape of the convex side of the inner semicircular cylindrical boss mold with a semi-cylinder attached. The lower pressing tool 2 adopts an inner semicircular cylindrical boss mold, one end of which is convex, and the inner side of the convex is adapted to the inner surface of the outer semicircular concave mold with a cavity. Circular through holes are distributed on both sides of the inner semicircular cylindrical boss mold and the outer semicircular concave mold. The circular through holes are used to connect and fix the outer semicircular concave mold with the inner cylindrical mold, and are closed and connected with the inner semicircular cylindrical boss mold positioning column through the corresponding outer semicircular concave mold positioning groove. The front pressure plate 3 and the rear pressure plate 4 respectively adopt two front and rear positioning chucks, which are two identical solid steel plates with inner convex structures. Circular through holes are processed on the plates, and the circular through holes cooperate with the outer semicircular concave mold. After the outer semicircular concave mold and the inner semicircular cylindrical boss mold are clamped, positioning chucks are used to connect them at both ends to position and tighten the upper press 1, the lower press 2, the front pressure plate 3, and the rear pressure plate 4.

[0047] This embodiment discloses a method for forming and preparing a composite material tube with a special-shaped structure, and the specific implementation steps are as follows:

[0048] Step 1: Cut the plain fabric composite material prepreg by a wire cutting machine.

[0049] Step 2, using an appropriate amount of acetone to clean the inner surfaces of the upper pressing tool 1 and the lower pressing tool 2 of the fixture for preparing the composite material cylinder with a turned-over structure, and evenly applying a release agent 2 to 3 times;

[0050] Step 3: Lay the pretreated rectangular slices of the plain fabric composite material in turn on the middle surface of the cleaned upper press 1, and use a roller scraper to scrape out the air between each layer of prepreg to keep the surface flat;

[0051] Step 4: Lay the pretreated rectangular slices of the plain fabric composite material on the pillow-shaped surfaces on both sides of the cleaned upper press 1 in sequence, and use a roller scraper to scrape out the air between each layer of prepreg, and keep the surface flat and keep good and stable contact with the connection with the middle surface of the upper press 1;

[0052] Step 5, repeatedly compact the lower pressing tool 2 and the upper pressing tool 1 to ensure that there is no gap between the plain fabric composite materials, and at the same time, use the pressing plates on both sides to flatten and compact the left and right sides;

[0053] Step 6: Screws are used to fix the fixture to ensure the stability of the overall fixture and that the composite material cylinder with the turned-over structure does not deform during the curing process. A total of 16 screws are used for fastening, wherein the upper press 1 and the lower press 2 are fastened with 3 screws on each of the horizontal sides to ensure that the longitudinal displacement is stable and does not slide during the heating process. The front and rear pressure plates are fastened with 5 screws each and the upper press 1 to ensure that the lateral displacement is stable and does not slide during the heating process.

[0054] Step 7, after tightening the screws of the combined mold longitudinally and transversely, place the mold in a heating box for semi-curing, the curing temperature is 80°C, and the curing time is 1 hour;

[0055] Step 8: Take the semi-cured assembled mold out of the heating box, tighten the screws again and place it in the heating box again for secondary curing at a curing temperature of 125°C for 2 hours;

[0056] Step 9: Take out the fully cured combined mold from the heating box, cool it to room temperature, take out the special-shaped composite material mold, and grind the end face of the obtained processed specimen to obtain a high-precision composite material special-shaped structure cylinder.

[0057] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, material or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, material or device.

[0058] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A forming die for a composite material tube with a special structure, characterized in that: It includes an upper press, a lower press, a front pressure plate, and a rear pressure plate; the upper press, the lower press, the front pressure plate, and the rear pressure plate all have through holes, and are assembled and fastened together by pins, thereby achieving a fixed position for the carbon fiber reinforced epoxy resin plain weave fabric composite material prepreg laid therein, which is convenient for integrated molding of a composite material cylinder with a flange; the upper press has an inner concave smooth semi-cylindrical surface, and the lower press has an outer convex smooth semi-cylindrical surface. The front pressure plate and the rear pressure plate are connected to the upper press by single-head connecting bolts on both sides, ensuring that the carbon fiber reinforced epoxy resin plain weave fabric composite material prepreg fits with the semi-cylindrical surface of the fixture, thereby achieving positioning of the composite material cylinder with a flange, and by adjusting the positioning position of the composite material cylinder with a flange to match, composite material cylinders with flanges of different thicknesses can be produced.

2. The forming die of a composite material tube with a special-shaped structure as claimed in claim 1, characterized in that: The upper pressing tool adopts an outer semicircular concave mold, one end of which is concave, and its concave side is adapted to the shape of the convex side of the inner semicircular cylindrical boss mold with a semi-cylinder attached; the lower pressing tool adopts an inner semicircular cylindrical boss mold, one end of which is convex, and the inner side of the convex is adapted to the inner surface of the outer semicircular concave mold with a cavity; circular through holes are distributed on both sides of the inner semicircular cylindrical boss mold and the outer semicircular concave mold, and the circular through holes are used to connect and fix the outer semicircular concave mold with the inner cylindrical mold The outer semicircular concave mold is fixed by the correspondingly arranged outer semicircular concave mold locating groove and the inner semi-cylindrical boss mold locating column. The front pressure plate and the rear pressure plate respectively adopt two front and rear positioning chucks, and the positioning chucks are two completely identical fixed plates with inner convex structures. There are circular through holes on the plates, and the circular through holes cooperate with the outer semicircular concave mold. After the outer semicircular concave mold and the inner semi-cylindrical boss mold are clamped, the positioning chucks are used to connect them at both ends to position and tighten the upper press, the lower press, the front pressure plate, and the rear pressure plate.

3. The forming die of a composite material tube with a special-shaped structure as claimed in claim 2, characterized in that: The inner semi-cylindrical boss mold and the outer semi-circular recessed mold are both made of steel; and the positioning chucks are two completely identical steel plates with inner convex structures.

4. A forming method for preparing a forming die for a composite material cylinder with a special-shaped structure, based on the forming die for a composite material cylinder with a flanged structure as claimed in claim 1, 2 or 3, characterized in that: The following steps are included: Step 1, cutting the carbon fiber reinforced epoxy resin plain fabric composite material prepreg into rectangles of a predetermined size by a wire cutting machine; Step 2: Use an appropriate amount of acetone to clean the inner surfaces of the upper pressing tool and the lower pressing tool of the fixture for preparing the composite material tube with a flanged structure, and evenly apply a release agent 2 to 3 times; Step 3, stacking the pretreated carbon fiber reinforced epoxy resin plain fabric composite rectangular slices in sequence on the middle surface of the cleaned upper press, and using a roller scraper to scrape out the air between each layer of prepreg to keep the surface flat; Step 4: Lay the pretreated rectangular slices of carbon fiber reinforced epoxy resin plain fabric composite material on the pillow-shaped surfaces on both sides of the cleaned upper press in sequence, and use a roller scraper to scrape out the air between each layer of prepreg, and keep the surface of each layer of prepreg flat and keep good and stable contact with the connection with the middle surface of the upper press; Step 5, repeatedly compact the lower pressing tool and the upper pressing tool to ensure that there is no gap between the carbon fiber reinforced epoxy resin plain fabric composite material, and at the same time, use the pressing plates on both sides to flatten and compact the left and right sides; Step 6: Use screws to fix the fixture to ensure the stability of the overall fixture and that the composite material cylinder with the turned-over structure does not deform during the curing process. A total of 16 screws are used for fastening. Step 7, tighten the screws of the combined mold longitudinally and transversely and place the mold in a heating box for semi-curing; Step 8, taking the semi-cured combined mold out of the heating box, tightening the screws again and placing it in the heating box again for secondary curing; the combined mold is a forming mold for the composite material tube with a flanging structure; Step 9: Take out the fully cured combined mold from the heating box, cool it to room temperature, take out the composite material mold with flanges, and grind the end face of the obtained processed specimen to obtain a high-precision composite material tube with a flange structure.

5. The forming preparation method according to claim 4, characterized in that: In step 1, the prepreg is cut by a wire cutting machine.

6. The forming preparation method according to claim 4, characterized in that: In step 6, 16 screws are used for fastening, among which the upper and lower press tools are fastened with 3 screws on each side horizontally to ensure that the longitudinal displacement is stable and does not slide during the heating process, and the front and rear pressure plates are fastened with the upper press tool with 5 screws each to ensure that the lateral displacement of the special-shaped structure cylinder is stable and does not slide during the heating process.

7. The forming preparation method according to claim 4, characterized in that: In step 7, the semi-curing temperature is 80° C. and the curing time is 1 hour.

8. The forming preparation method according to claim 4, characterized in that: In step 8, the secondary curing temperature is 125° C. and the curing time is 2 hours.

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