A continuous compression molding production system for a bistable composite material tube

Abstract

The present invention relates to a continuous molding production system for a bistable composite material tube, comprising a feeding unit, a molding unit, a slitting unit, and a winding unit arranged in sequence. The feeding unit is configured to synchronously feed prepregs with different resin contents and a release cloth made of Teflon into the molding unit. The molding unit is configured to have an upper pressing belt and a lower pressing belt with clearance fit, wherein an upper heating module is installed on the upper pressing belt and a lower heating module is provided under the lower pressing belt. The prepreg entering between the upper and lower pressing belts is bonded into a laminate by heating of the upper and lower heating modules, and the laminate is extruded by an upper pressing roller and a lower pressing roller. The slitting unit is configured to slit the extruded laminate according to width. The winding unit is configured to wind up the slit laminate. The present invention can be slit into products of multiple widths at one time. Compared with dry pultrusion, continuous molding is more efficient, does not require a special mold, and is low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a continuous molding production system for bistable composite material pipes. Background Art

[0002] In recent years, thin-shell structures made of bistable composite materials have attracted considerable attention, primarily due to the widespread application of foldable structures in aerospace applications, such as solar arrays, antennas, and various rod-shaped structures. Foldable structures can be broadly categorized into two types: those that change geometry through deformation and those formed by combining multiple structures.

[0003] In order to give full play to the multifunctionality of foldable structures such as light weight, excellent mechanical properties and high space utilization, the new concept design idea of self-excitation and self-locking of fiber composite materials has attracted great attention from aerospace engineering at home and abroad. Its main connotation is to achieve multi-stability by using thin-walled composite materials with anti-symmetric angle plies, that is, to use the process of the structure jumping from one stable state to another to make the structure unfold, and to control the overall structure through a series of adjustments to the multi-stable states of individual components to achieve the folding and unfolding requirements of the composite material structure.

[0004] Currently, the main methods for forming composite tubes include internal expansion bagging, winding, and dry and wet pultrusion. Compared to internal expansion belting and winding, continuous molding offers greater automation and efficiency, making it suitable for mass production. Compared to wet pultrusion, continuous molding offers a better working environment, controllable resin content, and the ability to tailor the resin content of different layer structures, which helps leverage the advantages of both foldable structures. Compared to dry pultrusion, continuous molding is more efficient and can be slit into multiple widths at once, resulting in higher efficiency, no need for specialized molds, and lower costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the prior art, the present invention provides a continuous molding production system for bistable composite material tubes.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a continuous molding production system for bistable composite material tubes, which comprises a feeding unit, a molding unit, a slitting unit and a winding unit arranged in sequence.

[0007] Among them, the feeding unit has a first barrel, a second barrel and a third barrel arranged from top to bottom to store prepregs, and a fourth barrel with a release cloth wound under the third barrel. The prepregs in the first barrel, the second barrel and the third barrel and the release cloth on the fourth barrel enter the molding unit synchronously.

[0008] The resin content of the prepreg stored in the first barrel is 50% to 55%, the resin content of the prepreg stored in the second barrel is 45% to 50%, and the resin content of the prepreg stored in the third barrel is 40% to 45%. The single layer thickness of each of the above prepregs is 0.05 to 0.8 mm; the width is 0.5 to 4 m.

[0009] In addition, the reinforcement in the prepreg can be glass fiber, carbon fiber, or a mixture of glass fiber and carbon fiber; the resin can be a tough thermosetting resin modified by epoxy, polyurethane, etc., or a thermoplastic resin such as PP, PA, PE; in particular, the prepreg used above can be a thermosetting prepreg or a thermoplastic prepreg.

[0010] Molding unit: It has an upper pressing belt and a lower pressing belt with a clearance fit. An upper heating module is installed on the upper pressing belt to fit the upper pressing belt, and a lower heating module is installed under the lower pressing belt to fit the lower pressing belt. The prepreg entering between the upper and lower pressing belts is heated by the upper and lower heating modules and bonded into a laminate. Upper and lower pressing rollers are installed at the discharge ends of the upper and lower pressing belts to extrude the laminate.

[0011] A slitting unit is used to slit the extruded laminate into widths;

[0012] The winding unit is used to wind up the slit laminated boards.

[0013] Furthermore, the molding unit has rotating guide rollers, which include three upper guide rollers distributed in a triangular shape and three lower guide rollers distributed in a triangular shape. The upper pressure belt is wound between the upper guide rollers, and the lower pressure belt is wound between the lower guide rollers.

[0014] Preferably, the upper pressing belt and the lower pressing belt are both made of Teflon belt or steel belt with a thickness of 0.05-0.2 mm.

[0015] In order to achieve precise temperature control during heating, the upper heating module and the lower heating module both have a first temperature control zone, a second temperature control zone and a third temperature control zone arranged along the width direction of the laminate. The length of the first temperature control zone and the third temperature control zone are both 1 / 8 to 1 / 4 of the length of the upper and lower heating modules, and the temperature is 3 to 10°C higher than that of the second temperature control zone.

[0016] In order to prevent the heating module from expanding and lengthening after heating to form a bow shape, which causes uneven thickness of the laminate in the width direction, the molding unit has a support assembly for installing the upper heating module and the lower heating module. The support assembly includes a support seat fixed on the base of the molding unit, and the support seat has a slide groove. An I-beam is slidingly provided in the slide groove. The I-beam is clearance-matched with the side of the slide groove, and the upper heating module and the lower heating module are fixed to the corresponding I-beams.

[0017] The beneficial effects of the present invention are as follows: the present invention adopts prepregs with different resin contents, which can ensure the stability of the formed bistable composite material tube in both the unfolded and rolled states. Due to the use of a continuous molding process, the production efficiency is high, the product stability is good, and the cost is low. Multiple large rolls of bistable composite material tubes can be formed at one time and can be cut according to the required length without the need for special molds, and the versatility is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below with reference to the accompanying drawings and examples.

[0019] Figure 1 It is a schematic diagram of the process structure of the present invention.

[0020] Figure 2 It is a schematic diagram of the temperature control zones of the heating module of the present invention.

[0021] Figure 3 It is a structural schematic diagram of the support assembly of the present invention.

[0022] Figure 4 Schematic diagram of the composite material tube of the present invention in a rolled-up state.

[0023] Figure 5 Schematic diagram of the composite material tube of the present invention in an unwinding state.

[0024] In the figure: 1. First barrel, 2. Second barrel, 3. Third barrel, 4. Fourth barrel, 5. Upper guide roller, 6. Lower guide roller, 7. Upper pressure belt, 8. Lower pressure belt, 9. Upper heating module, 10. Lower heating module, 11. Upper pressure roller, 12. Lower pressure roller, 13. Slitting unit, 14. Winding unit, 15. First temperature control zone, 16. Second temperature control zone, 17. Third temperature control zone, 18. Support assembly, 18-1. Support seat, 18-2. Slide, 18-3. I-beam. DETAILED DESCRIPTION

[0025] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0026] like Figure 1 The continuous molding production system for a bistable composite material tube shown in the figure uses a continuous molding machine to complete the molding process of the bistable composite material tube, and has a feeding unit, a molding unit, a slitting unit 13 and a winding unit 14 arranged in sequence according to the production process.

[0027] Feeding unit: From top to bottom, a first barrel 1, a second barrel 2 and a third barrel 3 are arranged. The first barrel 1 contains a first prepreg with a resin content of 55%, the second barrel 2 contains a second prepreg with a resin content of 50%, and the third barrel 3 contains a third prepreg with a resin content of 45%. The single layer thickness of each of the above prepregs is 0.5 mm and the width is 4 m.

[0028] A fourth barrel 4 wound with a release cloth is provided below the third barrel 3. The release cloth is made of Teflon. The purpose of the Teflon release cloth is to prevent the prepreg from sticking together after being heated, pressurized and rolled up by the molding unit, while ensuring the demoulding effect and heat transfer efficiency. The thickness of the release cloth used is 0.08 mm and the width is 4 m.

[0029] The molding unit, the main component of the continuous molding machine, includes guide rollers, including three upper guide rollers 5 and three lower guide rollers 6 arranged in a triangular pattern. An upper pressure belt 7 is wound between the three upper guide rollers 5, and a lower pressure belt 8 is wound between the three lower guide rollers 6. The lower surface of the upper pressure belt 7 is loosely matched with the upper surface of the lower pressure belt 8. A motor drives the upper and lower guide rollers 5, 6, to rotate at a speed of 2000 mm / min, thereby driving the upper and lower pressure belts 7, 8 to rotate synchronously, achieving the continuous molding process.

[0030] The upper pressing belt 7 and the lower pressing belt 8 are both made of Teflon belt with a thickness of 0.2 mm. Teflon is a self-releasing material, which can effectively prevent the prepreg from sticking to the upper pressing belt 7 and the lower pressing belt 8.

[0031] The prepregs in the first barrel 1 , the second barrel 2 , and the third barrel 3 and the release cloth on the fourth barrel 4 are synchronously conveyed into between the upper pressing belt 7 and the lower pressing belt 8 .

[0032] An upper heating module 9 is installed on the upper pressing belt 7 and is in contact with the upper pressing belt 7. A lower heating module 10 is provided under the lower pressing belt 8 and is in contact with the lower pressing belt 8. The prepreg entering between the upper pressing belt 7 and the lower pressing belt 8 is bonded into a laminate by heating by the upper heating module 9 and the lower heating module 10. An upper pressing roller 11 and a lower pressing roller 12 are provided at the discharge ends of the upper pressing belt 7 and the lower pressing belt 8 for cooperating to extrude the laminate.

[0033] like Figure 2 As shown, since the heat dissipation speed of the continuous molding machine is different in the width direction, the upper heating module 9 and the lower heating module 10 are provided with a first temperature control zone 15, a second temperature control zone 16 and a third temperature control zone 17 arranged along the width direction of the laminate, forming a zone control in the width direction of the continuous molding machine, and precise temperature control.

[0034] Generally speaking, the edge area of a continuous molding machine dissipates heat faster than the interior, so the temperature of the first temperature control zone 15 and the third temperature control zone 17 is 3 to 10°C higher than that of the second temperature control zone 16, and the first temperature control zone 15 and the third temperature control zone 17 are equal in length and both occupy 1 / 5 of the length of the upper and lower heating modules 9 and 10, and the second temperature control zone 16 occupies 3 / 5 of the length of the upper and lower heating modules 9 and 10.

[0035] Considering that the upper heating module 9 and the lower heating module 10 are easy to expand and lengthen after heating and become bow-shaped, resulting in uneven thickness of the laminate in the width direction, the molding unit also has a support assembly 18 for installing the upper heating module 9 and the lower heating module 10, such as Figure 3 As shown, the support assembly 18 includes a support base 18-1 fixed to the base of the molding unit. The support base 18-1 has a slide groove 18-2. An I-beam 18-3 slides within the slide groove 18-2. The I-beam 18-3 is clearance-matched with the side of the slide groove 18-2. The upper heating module 9 and the lower heating module 10 are fixed to the corresponding I-beam 18-3. In this way, after the upper heating module 9 and the lower heating module 10 are heated and expanded, they can slide within the slide groove 18-2, thereby ensuring the flatness of the upper heating module 9 and the lower heating module 10, which is conducive to controlling the thickness uniformity of the product.

[0036] The squeezing force of the upper pressing roller 11 and the lower pressing roller 12 can be achieved by controlling the gap between the two. The gap can be precisely controlled by a cylinder, and the optimal gap is 19 mm.

[0037] The slitting unit 13 is used to slit the extruded laminate according to width.

[0038] The winding unit 14 is used to wind up the slit laminate, and firstly wind up the bistable composite material tube in a winding state. Figure 4 As shown, the release cloth on the surface of the composite material tube is torn off, and then the tube is cut according to the required length to obtain a bistable composite material tube in an unrolled state, as shown Figure 5 shown.

[0039] The main process is briefly described as follows: the prepregs with different resin contents in the first barrel 1, the second barrel 2 and the third barrel 3 and the release cloth in the fourth barrel 4 are fed together in a top-down order between the upper pressing belt 7 and the lower pressing belt 8 of the molding unit. After being heated by the upper heating module 9 and the lower heating module 10, the layers of prepreg are bonded together to form a laminate, which tends to warp upward; then the laminate is squeezed by the upper pressing roller 11 and the lower pressing roller 12 of the molding unit to improve the internal bonding effect of the laminate; it is cut into multiple required widths by the slitting unit 13 and finally wound up by the winding unit 14.

[0040] The present invention has the following advantages:

[0041] 1. The continuous molding process is adopted, which has high production efficiency, high product stability, low cost, high degree of mechanization, and can form multiple large rolls of bistable composite material tubes at one time. It can be cut according to the required length without the need for special molds and has good versatility.

[0042] 2. Using prepregs with different resin contents ensures the stability of the final bistable composite tube in both the unfolded and reeled states. Both stable states are inward curled. This is because the innermost layer has a high resin content and large curing shrinkage, which causes the tube to maintain an inward curl.

[0043] 3. The use of a flexible resin system can ensure that the pipe will not be damaged by stress when used in both unfolded and reeled states.

[0044] 4. The bistable composite material tube can maintain stability in both the unfolded and reeled states. In the unfolded state, it provides a certain strength to be used as a supporting component. In the reeled state, it occupies a small volume and is easy to carry and transport, which has advantages over composite materials that cannot be reeled.

[0045] 5. The reverse forming method is adopted to form the bistable composite material tube in the unwinding state, and then the bistable composite material tube is transformed into the unwinding state while being cut.

[0046] 6. The slitting method can effectively ensure the straightness of the opening.

[0047] 7. The prepreg is laid in an antisymmetric structure, for example: (+a / -a / +a / -a / +a / -a) laying method.

[0048] 8. The present invention can produce the finished product in one step, saving materials, eliminating waste and being highly efficient.

[0049] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A continuous molding production system for bistable composite tubes, comprising a feeding unit, a molding unit, a slitting unit, and a winding unit arranged in sequence, characterized by: Feeding unit: It has a first barrel, a second barrel, and a third barrel containing prepregs arranged from top to bottom. A fourth barrel with a release cloth wound around it is located below the third barrel. The prepregs in the first, second, and third barrels and the release cloth on the fourth barrel are synchronously fed into the molding unit. Molding unit: It has an upper pressing belt and a lower pressing belt with a clearance fit. An upper heating module is installed on the upper pressing belt to fit the upper pressing belt, and a lower heating module is installed under the lower pressing belt to fit the lower pressing belt. The prepreg entering between the upper and lower pressing belts is heated by the upper and lower heating modules and bonded into a laminate. Upper and lower pressing rollers are installed at the discharge ends of the upper and lower pressing belts to extrude the laminate. The upper heating module and the lower heating module each have a first temperature control zone, a second temperature control zone and a third temperature control zone arranged along the width direction of the laminate. The length of the first temperature control zone and the third temperature control zone are 1 / 8 to 1 / 4 of the length of the upper and lower heating modules, and the temperature is 3 to 10 ° C higher than that of the second temperature control zone; The molding unit has a support assembly for installing the upper heating module and the lower heating module. The support assembly includes a support base fixed to the molding unit base. The support base has a slide groove. An I-beam is slidably arranged in the slide groove. The I-beam is clearance-matched with the side of the slide groove. The upper heating module and the lower heating module are fixed to the corresponding I-beam. After the upper heating module and the lower heating module are heated and expanded, they can slide in the slide groove. A slitting unit is used to slit the extruded laminate into widths; The winding unit is used to wind up the slit laminated boards.

2. The continuous molding production system according to claim 1, wherein: The molding unit has rotating guide rollers, which include three upper guide rollers distributed in a triangle and three lower guide rollers distributed in a triangle. The upper pressure belt is wound between the upper guide rollers, and the lower pressure belt is wound between the lower guide rollers.

3. The continuous molding production system according to claim 2, characterized in that: The upper pressing belt and the lower pressing belt are both made of Teflon belt or steel belt with a thickness of 0.05-0.2mm.

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