Vacuum preforming device and method for mould pressing of prepreg with positive pressure

Abstract

The device comprises a workbench, a sealing cover is arranged on the workbench, a containing cavity is formed between the sealing cover and the workbench, an elastic sealing film is arranged in the containing cavity and divides the containing cavity into a sealing cover oil cavity and a containing cavity, the sealing cover oil cavity is used for containing hydraulic oil, and the containing cavity is used for containing the hydraulic oil; a die is arranged in the containing cavity and used for containing a workpiece, the die is provided with an air passing hole, the elastic sealing film covers the die, when the sealing cover oil cavity is filled with hydraulic oil, the elastic sealing film gradually covers the workpiece, the workbench and the die, the workbench is provided with an exhaust hole, and the exhaust hole is communicated with the containing cavity and the exhaust channel. The problems of wrinkling, bulging and insufficient attaching force in the prepreg mold pressing process can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum preforming equipment, and in particular to a prepreg molding vacuum preforming device and method with positive pressure. Background Art

[0002] The vacuum preforming device for prepreg molding is used to exhaust and compact the carbon cloth ply of carbon fiber products. The existing vacuum preforming device for prepreg molding requires a vacuum device when in use. The carbon cloth is manually placed in the mold and placed on the vacuum machine table as a whole, and the carbon cloth is bonded by vacuuming. Although the existing technical solution can bond the carbon cloth, due to the sequence of the exhaust process and the force problems, there will be gas residue between the carbon cloth interlayers, causing bulging, which needs to be manually processed. The treated prepreg molded product will affect the strength of the final product, and the vacuum pressure on the carbon cloth is insufficient, which will cause the bonding to be not tight enough. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a prepreg molding vacuum preforming device and method with positive pressure, which can solve the problems of wrinkling, bulging and insufficient adhesion encountered in prepreg molding.

[0004] The specific technical scheme is as follows: A prepreg molding vacuum preforming device with positive pressure includes a workbench, a sealing cover is provided on the workbench, a containing cavity is formed between the sealing cover and the workbench, an elastic sealing membrane is provided in the containing cavity, the elastic sealing membrane separates the containing cavity into a sealing cover oil cavity and a storage cavity, the sealing cover oil cavity is used to contain hydraulic oil, a mold is provided in the storage cavity for setting a workpiece, the mold is provided with an air hole, the elastic sealing membrane cover is arranged above the mold, when the sealing cover oil cavity is filled with hydraulic oil, the elastic sealing membrane gradually covers the workpiece, the workbench and the mold, the workbench is provided with an exhaust hole, and the exhaust hole is respectively connected to the storage cavity and the exhaust channel.

[0005] In some embodiments, the sealing cover is provided with an oil inlet and an oil outlet which are in communication with the sealing cover oil chamber, and the oil inlet and the oil outlet are in communication with an oil control system.

[0006] In some embodiments, the oil control system includes first to fourth oil pumps, the first oil pump and the second oil pump are respectively connected to the supercharger, the third oil pump and the fourth oil pump are respectively connected to the oil inlet and the oil outlet, and the supercharger is connected to the oil inlet.

[0007] In some embodiments, the workbench is horizontally arranged, the mold is arranged in the middle of the workbench, the elastic sealing film cover is arranged on the workbench, and the cross-section of the elastic sealing film is arc-shaped and symmetrically arranged in an initial state.

[0008] In some embodiments, the exhaust passage is located below the workbench, and a plurality of exhaust holes are spaced apart above the exhaust passage.

[0009] In some embodiments, both ends of the mold are in contact with the workbench, the middle portion has a raised portion, the raised portion and the workbench are spaced apart, the workpiece is laid on the raised portion, and a plurality of air holes are spaced apart and pass through the raised portion.

[0010] In some embodiments, when the oil chamber of the sealing cover is completely filled with oil, the pressure reaches 20-200 MPa, and the exhaust passage is connected to the vacuum pump.

[0011] A method for a prepreg molding vacuum preforming device with positive pressure, comprising the following steps:

[0012] S100: The low-pressure hydraulic oil enters the sealing cover through the oil inlet through the oil pump, and the air inside the sealing cover is exhausted through the exhaust channel from the mold air hole and the workbench exhaust hole, so that the elastic sealing film gradually covers the workpiece, the workbench and the mold;

[0013] S200: After the hydraulic oil in the sealing cover oil chamber reaches the first preset pressure, the oil pump stops supplying oil, and the booster starts working, so that the high-pressure hydraulic oil enters the sealing cover oil chamber, and the internal pressure begins to increase until it reaches the second preset pressure, pressing the carbon cloth tightly and removing the internal bubbles.

[0014] In some embodiments, in step S100, when low-pressure hydraulic oil is input, the second oil pump is started to fill the high-pressure end of the supercharger with hydraulic oil, and the third oil pump is started to deliver low-pressure hydraulic oil through the oil inlet to fill the oil chamber of the sealing cover.

[0015] In some embodiments, in step S200, after the pressure in the oil chamber of the sealing cover reaches a first preset pressure, the third oil pump is turned off, the first oil pump is started to start the booster, and the high-pressure hydraulic oil enters the oil chamber of the sealing cover through a one-way valve to make the interior reach a set second preset pressure. After the compression is completed, the pressure is released through the solenoid valve, and then the hydraulic sealing cover is restored by the fourth oil pump.

[0016] Technical effect of the present invention: The present invention processes exhaust holes on the workbench, and the vacuum machine vacuums the enclosed space through the exhaust channel, seals the outside of the workbench, and fills it with high-pressure liquid, so that it acts on the surface of the elastic sealing film to press the prepreg molded workpiece, and at the same time exhausts the air inside it, so that it fits tightly and has higher strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 Schematic diagram of a prepreg molding vacuum preforming device with positive pressure according to an embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of the hydraulic oil after filling according to the embodiment of the present invention.

[0020] Figure 3 Schematic diagram of an oil control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0025] like Figures 1 to 3 As shown, a prepreg molding vacuum preforming device with positive pressure in this embodiment includes a workbench 1, a sealing cover 2 is provided on the workbench 1, and a receiving cavity is formed between the sealing cover 2 and the workbench 1. An elastic sealing membrane 3 is provided in the receiving cavity, and the elastic sealing membrane 3 divides the receiving cavity into a sealing cover oil cavity 31 and a storage cavity 32. The sealing cover oil cavity 31 is used to contain hydraulic oil, and a mold 4 is provided in the storage cavity 32 for setting a workpiece 5. The mold 4 is provided with an air hole 41, and gas can be discharged through the air hole 41. The elastic sealing membrane 3 is covered above the mold 4. When the sealing cover oil cavity 31 is filled with hydraulic oil, the elastic sealing membrane 3 gradually covers the workpiece 5, the workbench 1 and the mold 4. The workbench 1 is provided with an exhaust hole 11, and the exhaust hole 11 is connected to the storage cavity 32 and the exhaust channel 6 respectively. In the above technical scheme, the sealing cover 2 and the workbench 1 are closed, so that the sealing cover 2 covers the prepreg molded workpiece 5, and low-pressure hydraulic oil enters the sealing cover, while the internal air is exhausted. The internal air is exhausted from the air hole 41 of the mold 4 and the exhaust hole 11 of the workbench 1, so that the elastic sealing membrane 3 gradually covers the prepreg molded laminated workpiece 5, the workbench and the mold, until the hydraulic oil in the sealing cover oil chamber 31 reaches the first preset pressure (5MPa in this embodiment), and the low-pressure hydraulic oil stops entering; at the same time, high-pressure hydraulic oil enters the sealing cover oil chamber, so that the internal pressure begins to increase, and the pressure can reach the second preset pressure (20-200MPa in this embodiment), that is, the pressure applied to the prepreg molded laminated workpiece 5 can reach 20-200MPa, the carbon cloth is pressed tightly and fitted, and the internal bubbles are exhausted, so as to achieve the purpose of tight fitting. In this embodiment, the entire workpiece is made of carbon cloth, which is generally a plurality of layers of carbon cloth stacked one on top of the other. It is often used for workpieces with weight requirements and parts that need to bear a larger load. Generally, the tighter the compression, the cleaner the internal gas is discharged, and the higher the strength of the workpiece will be.

[0026] Compared with the prior art, the present embodiment uses an elastic sealing film 3, so there is no need to manually pull the sealing cloth during vacuuming during use, so that the sealing cloth laid on the carbon cloth layer is smooth and wrinkle-free, and wrinkles are prevented from forming on the workpiece surface, causing the carbon cloth to form an angle in this area and protrude in this area. The elastic sealing film 3 is recessed inward from the initial position and adheres to the workbench behind the elastic sealing film 3 under the cover. Since the workpiece is in a relatively high position, it is adhered to the prepreg molded workpiece before the elastic sealing film 3 is stretched, and is in a smooth state, so no wrinkles are generated.

[0027] Secondly, since external pressure is provided to enable greater pressure to act on the surface of the workpiece, and the liquid pressure acts on each position with equal magnitude, the high-pressure hydraulic oil is located on one side of the elastic sealing membrane. When the elastic sealing membrane is attached to the depressions and protrusions on the surface of the laminated workpiece, they can obtain the same positive pressure, so the fit is tighter and more uniform.

[0028] Furthermore, since it provides positive pressure while evacuating the air, the two actions are performed simultaneously, so that the air inside the prepreg molded workpiece can be exhausted to obtain a smoother product.

[0029] In addition, the problem of bloating is solved, so there is no need to cut through the structural layer for reprocessing, which affects the strength of the product, and carbon fiber parts with designed strength can be obtained.

[0030] In this embodiment, the sealing cover 2 is provided with an oil inlet 21 and an oil outlet 22 connected to the sealing cover oil chamber 31, and the oil inlet 21 and the oil outlet 22 are connected to an oil control system, so that oil can enter and exit the sealing cover oil chamber 31 through the oil inlet 21 and the oil outlet 22. The oil control system includes first to fourth oil pumps, namely, a first oil pump J1, a second oil pump J2, a third oil pump J3 and a fourth oil pump J4, the first oil pump J1 and the second oil pump J2 are connected to the supercharger 7, the third oil pump J3 and the fourth oil pump J4 are connected to the oil inlet 21 and the oil outlet 22, respectively, and the supercharger 7 is connected to the oil inlet 21. The control process of the oil control system is as follows: the second oil pump J2 is started to fill the high-pressure end of the supercharger 7 with hydraulic oil, and the third oil pump J3 is started to deliver low-pressure hydraulic oil through the oil inlet 21 to fill the oil chamber of the sealing cover; then the third oil pump J3 is closed, and the first oil pump J1 is started to start the supercharger, so that the high-pressure hydraulic oil enters the oil chamber 31 of the sealing cover through the one-way valve F4 (set to 20MPa) to make the internal pressure reach the set pressure. After the compaction is completed, the pressure is released through the solenoid valve F6, and then the sealing cover is restored through the fourth oil pump J4. Through the above technical scheme, not only can the carbon cloth be more closely attached, but also because the hydraulic oil acts on the elastic sealing membrane and the pressure of each position of the internal pressure of the hydraulic oil is equal, the pressure of each position of the carbon cloth is equal, and for the uneven carbon cloth prepreg molded workpiece, it also has good pressure and good compaction uniformity.

[0031] In this embodiment, the workbench 1 is arranged horizontally, the mold 4 is arranged in the middle of the workbench 1, and the elastic sealing membrane 3 is covered on the workbench 1. The cross section of the elastic sealing membrane 3 is arc-shaped and symmetrically arranged in the initial state, so that the elastic sealing membrane 3 is evenly force-fitted on the workpiece. The exhaust channel 6 is located below the workbench 1, and a plurality of exhaust holes 11 are arranged above the exhaust channel 6 at intervals, so that the air can be discharged quickly. The two ends of the mold 4 are in contact with the workbench 1, and there is a ridge 42 in the middle. The ridge 42 is arranged at intervals with the workbench 1. The workpiece 5 is laid on the ridge 42, and a plurality of air holes 41 are arranged at intervals and penetrate the ridge 42, so that the workpiece is in a higher position, and the ridge is U-shaped. When the oil chamber 31 of the sealing cover is filled with oil, the pressure reaches 20-200Mpa, and the exhaust channel 6 is connected to the vacuum pump, and the air is evacuated by the vacuum pump. The vacuum pump is a conventional device and is no longer displayed.

[0032] A method for a prepreg molding vacuum preforming device with positive pressure, comprising the following steps: S100: low-pressure hydraulic oil is pumped into the sealing cover 2 through the oil inlet 21, and the air inside the sealing cover 2 ( Figure 1 The middle arrow indicates the direction of air flow) and is exhausted from the air holes 41 of the mold and the exhaust holes 11 of the workbench 1 through the exhaust channel 6, so that the elastic sealing film 3 gradually covers the workpiece 5, the workbench 1 and the mold 4; S200: until the hydraulic oil in the oil chamber 31 of the sealing cover reaches the first preset pressure, the oil pump stops supplying oil, and the supercharger 7 starts working, so that the high-pressure hydraulic oil enters the oil chamber 31 of the sealing cover, and the internal pressure begins to increase until the second preset pressure, the carbon cloth is pressed tightly and the internal bubbles are removed.

[0033] Furthermore, in step S100, when the low-pressure hydraulic oil is input, the second oil pump J2 is started to fill the high-pressure end of the supercharger 7 with hydraulic oil, and the third oil pump J3 is started to deliver the low-pressure hydraulic oil through the oil inlet to fill the sealing cover oil chamber 31. In step S200, after the pressure of the sealing cover oil chamber 31 reaches the first preset pressure, the third oil pump J3 is closed, the first oil pump J1 is started to start the supercharger 7, and the high-pressure hydraulic oil enters the sealing cover oil chamber through the one-way valve F4 to make the inside reach the set second preset pressure. After the compaction is completed, the pressure is released through the solenoid valve F6, and then the hydraulic sealing cover is restored through the fourth oil pump J4.

[0034] A prepreg molding vacuum preforming device and method with positive pressure in this embodiment applies a positive pressure to the prepreg molded product, and the positive pressure is provided by liquid; an elastic sealing film is used to solve the problem that the sealing cloth is prone to wrinkles; and a booster is used to solve the problem of providing external positive pressure.

[0035] The above is a description of a vacuum preforming device and method for prepreg molding with positive pressure of the present invention. However, the present invention is not limited to the above specific implementation methods. Various modifications or changes can be made as long as they do not depart from the scope of the claims. The present invention includes various modifications and changes within the scope of the claims.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prepreg molding vacuum preforming device with positive pressure, characterized in that: It includes a workbench, a sealing cover is arranged on the workbench, a containing cavity is formed between the sealing cover and the workbench, an elastic sealing membrane is arranged in the containing cavity, the elastic sealing membrane divides the containing cavity into a sealing cover oil cavity and a storage cavity, the sealing cover oil cavity is used to contain hydraulic oil, a mold is arranged in the storage cavity for setting a workpiece, the mold is provided with an air hole, the elastic sealing membrane cover is arranged above the mold, when the sealing cover oil cavity is filled with hydraulic oil, the elastic sealing membrane gradually covers the workpiece, the workbench and the mold, the workbench is provided with an exhaust hole, and the exhaust hole is respectively connected with the storage cavity and the exhaust channel.

2. The prepreg molding vacuum preforming device with positive pressure according to claim 1, characterized in that: The sealing cover is provided with an oil inlet and an oil outlet which are in communication with the sealing cover oil cavity, and the oil inlet and the oil outlet are in communication with the oil control system.

3. The prepreg molding vacuum preforming device with positive pressure according to claim 2, characterized in that: The oil control system includes first to fourth oil pumps, the first oil pump and the second oil pump are respectively connected to the supercharger, the third oil pump and the fourth oil pump are respectively connected to the oil inlet and the oil outlet, and the supercharger is connected to the oil inlet.

4. The prepreg molding vacuum preforming device with positive pressure according to claim 1, characterized in that: The workbench is arranged horizontally, the mold is arranged in the middle of the workbench, the elastic sealing film cover is arranged on the workbench, and the cross section of the elastic sealing film is arc-shaped and symmetrically arranged in an initial state.

5. The prepreg molding vacuum preforming device with positive pressure according to claim 4, characterized in that: The exhaust passage is located below the workbench, and a plurality of exhaust holes are arranged above the exhaust passage at intervals.

6. The prepreg molding vacuum preforming device with positive pressure according to claim 5, characterized in that: The two ends of the mold are in contact with the workbench, the middle part has a raised part, the raised part and the workbench are arranged at intervals, the workpiece is laid on the raised part, and a plurality of air holes are arranged at intervals and penetrate the raised part.

7. The prepreg molding vacuum preforming device with positive pressure according to claim 6, characterized in that: When the oil chamber of the sealing cover is completely filled with oil, the pressure reaches 20-200Mpa, and the exhaust channel is connected to the vacuum pump.

8. A method for the prepreg molding vacuum preforming device with positive pressure as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: S100: The low-pressure hydraulic oil enters the sealing cover through the oil inlet through the oil pump, and the air inside the sealing cover is exhausted through the exhaust channel from the mold air hole and the workbench exhaust hole, so that the elastic sealing film gradually covers the workpiece, the workbench and the mold; S200: After the hydraulic oil in the sealing cover oil chamber reaches the first preset pressure, the oil pump stops supplying oil, and the booster starts working, so that the high-pressure hydraulic oil enters the sealing cover oil chamber, and the internal pressure begins to increase until it reaches the second preset pressure, pressing the carbon cloth tightly and removing the internal bubbles.

9. The prepreg molding vacuum preforming method with positive pressure according to claim 8, characterized in that: In step S100, when low-pressure hydraulic oil is input, the second oil pump is started to fill the high-pressure end of the supercharger with hydraulic oil, and the third oil pump is started to deliver low-pressure hydraulic oil through the oil inlet to fill the oil chamber of the sealing cover.

10. The prepreg molding vacuum preforming method with positive pressure according to claim 9, characterized in that: In step S200, after the pressure in the oil chamber of the sealing cover reaches the first preset pressure, the third oil pump is turned off, the first oil pump is started to start the booster, and the high-pressure hydraulic oil enters the oil chamber of the sealing cover through the one-way valve to make the interior reach the set second preset pressure. After the compression is completed, the pressure is released through the solenoid valve, and then the hydraulic sealing cover is restored by the fourth oil pump.

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