Vacuum forming device and method

Abstract

The invention provides a vacuum forming device and method. The vacuum forming device comprises a forming cavity; a resin storage part; the first flow path comprises a first branch and a second branch, and a first control valve is arranged between the first branch and the second branch; a vacuumizing part; a second control valve is arranged on the second flow path; the forming cavity is arranged in the heating cavity; and the control part is electrically connected with the vacuumizing part, the first control valve and the second control valve. In the vacuum forming device, the control part can control opening and closing of the first control valve, the second control valve and the vacuumizing part, and after the first branch is filled with resin, extraction of the resin is stopped. And then vacuumizing is continued, air in the second branch, the forming cavity and the second flow path is exhausted, and the internal porosity of the formed part obtained after curing in the forming cavity is reduced. In addition, the forming cavity is formed in the heating cavity, and after resin pouring is completed, the forming cavity can be directly heated through the heating cavity to achieve curing of the resin.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vacuum forming, and in particular to a vacuum forming device and method. Background Art

[0002] Vacuum assisted infusion molding is an advanced manufacturing technology that has occupied an important position in many high-end manufacturing fields with its unique advantages. This process generally uses vacuum bag molding technology to impregnate resin-based composite materials into the mold and fully infiltrate the preformed parts. After curing, the resin-based composite material product is obtained. It uses the vacuum environment to optimize the flow and filling process of the resin, thereby achieving high-precision and high-quality product manufacturing.

[0003] However, during the infusion process, due to the presence of air in the pipe connecting the resin and the preform, more or less bubbles will inevitably appear in the vacuum bag, resulting in high porosity and poor mechanical properties inside the composite material. Summary of the invention

[0004] In order to solve the problems existing in the related art, the present disclosure provides a vacuum forming device and method.

[0005] According to a first aspect of an embodiment of the present disclosure, there is provided a vacuum forming device, comprising:

[0006] A molding cavity, in which the preform is placed;

[0007] A resin storage unit, used for containing resin;

[0008] a first flow path, the resin storage portion is connected to the first end of the molding cavity through the first flow path, the first flow path includes a first branch and a second branch, a first control valve is provided between the first branch and the second branch, and the resin storage portion is connected to the first control valve through the first branch;

[0009] Vacuuming unit;

[0010] a second flow path, through which the vacuum pump is connected to the second end of the molding cavity, and a second control valve is provided on the second flow path;

[0011] A heating chamber, wherein the molding chamber is placed in the heating chamber;

[0012] The control unit is electrically connected to the vacuum pumping unit, the first control valve, and the second control valve. The control unit is used to control the first control valve, the second control valve, and the vacuum pumping unit so that after the first branch is filled with resin, the first control valve is closed and the vacuum pumping unit is controlled to vacuum the second branch, the molding cavity, and the second flow path, and the first control valve is opened after the vacuum pumping is completed to infuse the molding cavity with resin.

[0013] In some embodiments of the present disclosure, the opening of the first control valve is adjustable; and / or the opening of the second control valve is adjustable.

[0014] In some embodiments of the present disclosure, the first control valve comprises a two-insert ball valve; and / or,

[0015] The second control valve comprises a double-inserted ball valve.

[0016] In some embodiments of the present disclosure, the resin storage portion is placed in the heating chamber.

[0017] In some embodiments of the present disclosure, the vacuuming portion is located outside the heating chamber.

[0018] According to a second aspect of an embodiment of the present disclosure, a vacuum forming method is provided, using the vacuum forming device as described above, the vacuum forming method comprising:

[0019] Opening the first control valve, the second control valve and the vacuum pumping unit to allow the resin in the resin storage unit to flow to the first branch pipe;

[0020] When the resin fills the first branch pipe, closing the first control valve;

[0021] When the pressure of the vacuuming part reaches a preset value, the first control valve is opened to inject the resin into the molding cavity through the first branch pipe and the second branch pipe;

[0022] After the resin is poured into the molding cavity, the second control valve, the first control valve and the vacuum pumping part are closed.

[0023] In some embodiments of the present disclosure, opening the first control valve includes: opening the first control valve to a preset opening, wherein the preset opening is smaller than a fully open opening of the first control valve.

[0024] In some embodiments of the present disclosure, the preset opening is 1 / 5-1 / 2 of the full opening of the first control valve.

[0025] In some embodiments of the present disclosure, closing the second control valve, the first control valve and the vacuum pumping part includes:

[0026] The second control valve, the first control valve, and the vacuum pumping unit are closed in sequence.

[0027] In some embodiments of the present disclosure, after the resin is poured into the molding cavity, the second control valve, the first control valve and the vacuum pumping part are opened for a preset time period and then closed.

[0028] The beneficial effects of the present disclosure include but are not limited to: in the vacuum forming device provided by the present disclosure, the control unit can control the opening and closing of the first control valve, the second control valve and the vacuum pumping unit, so as to stop the extraction of resin after the first branch is filled with resin. Then continue to evacuate the air in the second branch, the molding cavity and the second flow path, and then extract and infuse the molding cavity with resin, so as to ensure that there are no bubbles in the resin entering the molding cavity at the beginning, reduce the internal porosity of the molded part (resin-based composite material) obtained after curing in the molding cavity, and thus improve its mechanical properties. In addition, in the vacuum forming device, the molding cavity is arranged in the heating cavity, so that after the resin infusion is completed, the molding cavity can be directly heated by the heating cavity to achieve the curing of the resin, avoiding the problem of uneven distribution of the resin due to shaking and easy generation of bubbles when the molding cavity is transported to the heating cavity after the resin infusion is completed.

[0029] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings incorporated into the specification and constituting a part of the specification illustrate embodiments of the present disclosure and are used together with the description to explain the principles of the embodiments of the present disclosure. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present disclosure, rather than all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of a vacuum forming device according to an exemplary embodiment of the present disclosure;

[0032] Figure 2 The figure is a schematic flow chart of a vacuum forming method according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present disclosure clearer, the technical solution of the present disclosure will be clearly and completely described in combination with the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be arbitrarily combined with each other without conflict.

[0034] The vacuum-assisted infusion molding process generally uses vacuum bag molding technology to impregnate the resin-based composite material into the mold and fully infiltrate the preform. After curing, the resin-based composite material product is obtained. It optimizes the flow and filling process of the resin by using the vacuum environment, thereby achieving high-precision and high-quality product manufacturing. However, during the infusion process, due to the presence of air in the pipe connecting the resin and the preform, more or less bubbles will inevitably appear in the vacuum bag, resulting in high porosity and poor mechanical properties inside the composite material.

[0035] In order to solve the above technical problems, the present disclosure provides a vacuum forming device, in which the control unit can control the opening and closing of the first control valve, the second control valve and the vacuum unit, so as to stop the extraction of resin after the first branch is filled with resin. Then continue to evacuate the air in the second branch, the molding cavity and the second flow path, and then extract and infuse the molding cavity with resin, so as to ensure that there are no bubbles in the resin entering the molding cavity at the beginning, reduce the internal porosity of the molded part (resin-based composite material) obtained after curing in the molding cavity, and thus improve its mechanical properties. In addition, in the vacuum forming device, the molding cavity is arranged in the heating cavity, so that after the resin infusion is completed, the molding cavity can be directly heated by the heating cavity to achieve the curing of the resin, avoiding the problem of uneven distribution of the resin due to shaking and easy generation of bubbles when the molding cavity is transported to the heating cavity after the resin infusion is completed.

[0036] The present disclosure provides a vacuum forming device. Figure 1As shown, the vacuum forming device 100 includes a forming cavity 10, a resin storage unit 20, a first flow path 30, a vacuum pumping unit 40, a second flow path 50, a heating cavity 60 and a control unit (not shown in the figure). The preform is placed in the forming cavity 10. The resin storage unit 20 is used to hold resin 21. The resin storage unit 20 is connected to the first end 11 of the forming cavity 10 through the first flow path 30. The first flow path 30 includes a first branch 31 and a second branch 32. A first control valve 71 is provided between the first branch 31 and the second branch 32. The resin storage unit 20 is connected to the first control valve 71 through the first branch 31. The vacuum pumping unit 40 is connected to the second end 12 of the forming cavity 10 through the second flow path 50. The second flow path 50 is provided with a second control valve 72. The forming cavity 10 is placed in the heating cavity 60. The control unit is electrically connected to the vacuum pumping unit 40, the first control valve 71, and the second control valve 72. The control unit is used to control the first control valve 71, the second control valve 72, and the vacuum pumping unit 40, so that after the first branch 31 is filled with resin, the first control valve 71 is closed and the vacuum pumping unit 40 is controlled to vacuum the second branch 32, the molding cavity 10, and the second flow path 50, and after the vacuum pumping is completed, the first control valve 71 is opened to inject resin into the molding cavity 10.

[0037] In the vacuum forming device 100 of the present embodiment, the control unit can control the opening and closing of the first control valve 71, the second control valve 72 and the vacuum unit 40, so as to stop the extraction of resin after the first branch 31 is filled with resin. Then continue to evacuate to exhaust the air in the second branch 32, the molding cavity 10 and the second flow path 50, and then extract and infuse the molding cavity 10 with resin, so as to ensure that there are no bubbles in the resin entering the molding cavity 10 at the beginning, reduce the internal porosity of the molded part (resin-based composite material) obtained after curing in the molding cavity 10, and thus improve its mechanical properties. In addition, in the vacuum forming device 100, the molding cavity 10 is arranged in the heating cavity 60, so that after the resin infusion is completed, the molding cavity 10 can be directly heated by the heating cavity 60 to achieve the curing of the resin, avoiding the problem of uneven distribution of the resin and easy generation of bubbles caused by shaking when the molding cavity 10 is transported to the heating cavity 60 after the resin infusion is completed.

[0038] Exemplarily, the heating chamber 60 in this embodiment may be an inner chamber of a forced air oven with a maximum heating temperature of 250° C. For example, the size of the inner chamber may be 800 mm*800 mm*1600 mm.

[0039] Exemplarily, the vacuuming part 40 may be a vacuum pump.

[0040] Illustratively, the resin storage portion 20 may be a beaker.

[0041] Exemplarily, the first flow path 30 and the second flow path 50 may be polytetrafluoroethylene tubes.

[0042] In one embodiment, if Figure 1 As shown, the opening degree of the first control valve 71 is adjustable, and the opening degree of the second control valve 72 is adjustable.

[0043] In this embodiment, the opening of the first control valve 71 can control the speed of the resin injection into the molding cavity 10, and can also control the speed of the resin extraction into the first flow path 30. The first control valve 71 is set to have an adjustable opening, and the opening of the first control valve 71 can be controlled by the control unit to control the speed of the resin injection into the molding cavity 10 and the speed of the resin extraction into the first flow path 30.

[0044] In addition, the opening of the second control valve 72 can control the vacuuming speed of the vacuuming part 40. The second control valve 72 is set to have an adjustable opening, and the opening of the second control valve 72 can be controlled by the control part to control the vacuuming speed of the vacuuming part 40.

[0045] In one embodiment, if Figure 1 As shown, the first control valve 71 includes a two-insertion ball valve, and the second control valve 72 includes a two-insertion ball valve.

[0046] In this embodiment, the first control valve 71 can control the speed of resin injection into the molding cavity 10, and can also control the speed of resin extraction into the first flow path 30. The first control valve 71 is set as a two-plug ball valve, which is easy to switch, small in size, convenient for controlling the flow rate of resin, simple in structure, easy to maintain, reliable in sealing, and can prevent air from entering the molding cavity 10 to cause pores in the molded part.

[0047] The opening of the second control valve 72 can control the speed of vacuuming the vacuuming part 40. The second control valve 71 is set as a two-plug ball valve, which is easy to switch, small in size, and convenient for controlling the speed of vacuuming the vacuuming part 40. It has a simple structure, convenient maintenance, reliable sealing, and can prevent air from entering the molding cavity 10 to cause pores in the molded part.

[0048] In one embodiment, if Figure 1 As shown, the resin storage portion 20 is placed in the heating chamber 60 .

[0049] The resin storage part 20 is placed in the heating chamber 60, and during the resin infusion process, the resin 21 in the resin storage part 20 can be preheated by the heating chamber 60, for example, preheated to about 100°C, to reduce the viscosity of the resin 21, and ensure the fluidity of the resin 21, so that the resin 21 can be sucked into the molding cavity 10 for infusion when the vacuum part 40 is evacuated to generate negative pressure. In addition, the resin storage part 20 is directly placed in the heating chamber 60, without the need to provide an additional preheating device, and without the need to penetrate the resin delivery pipeline on the wall of the heating chamber 60, which is conducive to the sealing of the heating chamber 60, ensuring that the temperature of the heating chamber 60 remains stable during the resin curing process, thereby ensuring the effect of resin curing and the performance of the molded part.

[0050] It should be noted that after the resin is poured into the molding cavity 10 , the resin storage portion 20 can be taken out of the heating cavity 60 .

[0051] In one embodiment, if Figure 1 As shown, the vacuuming part 40 is located outside the heating chamber 60. The vacuuming part 40 is located outside the heating chamber 60, which facilitates timely maintenance of the vacuuming part 40. In addition, placing the vacuuming part 40 outside the heating chamber 60 can prevent high-temperature damage to the components in the vacuuming part 40 when the heating chamber 60 performs high-temperature curing on the resin.

[0052] The present disclosure provides a vacuum forming method, using the vacuum forming device provided in the above embodiment of the present disclosure, combined with Figure 1-2 As shown, the vacuum forming method includes:

[0053] S100, opening the first control valve, the second control valve and the vacuum pumping unit to allow the resin in the resin storage unit to flow to the first branch pipe.

[0054] S200: When the resin fills the first branch pipe, close the first control valve.

[0055] refer to Figure 1 After the resin 21 in the resin storage part 20 flows to the first branch pipe 31 and is filled, the air in the first branch pipe 31 can be discharged, and the end of the first branch pipe 31 connected to the resin storage part 20 is inserted below the liquid level of the resin 21, which can ensure that no air enters after the subsequent resin is absorbed into the first branch pipe 31 and then poured into the molding cavity 10.

[0056] S300, when the pressure of the vacuum part reaches a preset value, the first control valve is opened to inject resin into the molding cavity through the first branch pipe and the second branch pipe.

[0057] When the resin fills the first branch pipe 31, the air in the first branch pipe 31 is exhausted. At this time, the first control valve 71 is closed, but the second control valve 72 and the vacuum pumping unit 40 are still opened, and the vacuum pumping unit 40 continues to vacuum the second branch pipe 32, the molding cavity 10 and the second flow path 50. When the pressure of the vacuum pumping unit 40 reaches a preset value, for example, -0.099 MPa, it indicates that the air in the second branch pipe 32, the molding cavity 10 and the second flow path 50 is completely exhausted. At this time, the first control valve 71 is opened, and the resin is poured into the molding cavity 10 through the first branch pipe 31 and the second branch pipe 32, which can ensure that there is no air in the molding cavity 10, and also ensure that there are no pores in the molded part obtained after the resin in the molding cavity is cured, thereby ensuring the mechanical properties of the molded part.

[0058] S400, after the molding cavity is filled with resin, the second control valve, the first control valve and the vacuum pumping unit are closed.

[0059] The vacuum forming method provided in this embodiment can control the opening and closing of the first control valve, the second control valve and the vacuum pumping part, so as to stop extracting the resin after the first branch is filled with resin. Then continue to vacuumize to exhaust the air in the second branch, the molding cavity and the second flow path, and then extract and inject the resin into the molding cavity, so as to ensure that there are no bubbles in the resin entering the molding cavity at the beginning, reduce the internal porosity of the molded part (resin-based composite material) obtained after curing in the molding cavity, and improve its mechanical properties.

[0060] In one embodiment, opening the first control valve includes: opening the first control valve to a preset opening, wherein the preset opening is smaller than a fully open opening of the first control valve.

[0061] In this example, the first control valve, the second control valve and the vacuum pumping unit are opened so that the resin in the resin storage unit flows to the first branch pipe and fills the first branch pipe, and the air in the first branch pipe can be discharged. When the first control valve is opened, the first control valve is opened to a preset opening that is less than the full opening of the first control valve, that is, when the first control valve is opened, the first control valve is opened to a smaller opening, which can ensure that the resin in the resin storage unit slowly flows to the first branch pipe and fills the first branch pipe, avoiding the generation of bubbles in the resin due to the excessively fast extraction speed of the resin, which affects the mechanical properties of the molded part obtained after curing in the molding cavity. In addition, when the first control valve is opened, the first control valve is opened to a smaller opening, and the first control valve can be closed in time at the moment when the resin fills the first branch pipe, so as to avoid the resin being drawn into the second branch pipe, which affects the subsequent exhaust work in the second branch pipe, the molding cavity and the second flow path.

[0062] In one embodiment, the preset opening degree is 1 / 5-1 / 2 of the full opening degree of the first control valve.

[0063] In this example, when the first control valve is opened, the first control valve is opened to 1 / 5-1 / 2 of the full opening, such as 1 / 4 or 1 / 3, to ensure that the resin in the resin storage unit slowly flows into the first branch pipe and fills the first branch pipe, avoiding the generation of bubbles in the resin due to the resin being extracted too quickly, thereby affecting the mechanical properties of the molded part obtained after curing in the molding cavity. In addition, when the first control valve is opened, the first control valve is opened to 1 / 5-1 / 2 of the full opening, such as 1 / 4 or 1 / 3, and the first control valve can be closed in time at the moment when the resin fills the first branch pipe, thereby avoiding the resin being drawn into the second branch pipe, thereby affecting the subsequent exhaust work in the second branch pipe, the molding cavity, and the second flow path.

[0064] In one embodiment, in combination Figure 1 As shown, closing the second control valve 72, the first control valve 71 and the vacuum pumping part 40 includes: closing the second control valve 72, the first control valve 71 and the vacuum pumping part 40 in sequence.

[0065] In this embodiment, after the resin is poured into the molding cavity 10, the second control valve 72 is first closed to interrupt the vacuuming part 40 from evacuating the molding cavity 10, that is, to interrupt the pouring of the resin into the molding cavity 10. Secondly, the first control valve 71 is closed to further interrupt the pouring of the resin into the molding cavity 10. Finally, the vacuuming part 40 is closed so that the vacuuming part 40 can always work to maintain the vacuum state of the entire system before the resin completely stops pouring, thereby preventing gas from entering the molding cavity 10 and affecting the mechanical properties of the molded part obtained after curing in the molding cavity 10.

[0066] It should be noted that, in this embodiment, the second control valve 72 is closed first and then the first control valve 71 is closed, so that after the resin is poured into the molding cavity 10, the vacuuming part 40 is first interrupted to evacuate the molding cavity 10 to interrupt the pouring of the resin into the molding cavity 10, and then the first control valve 71 is closed to further interrupt the pouring of the resin into the molding cavity 10. If the first control valve 71 is closed first and then the second control valve 72 is closed, the pouring of the resin into the molding cavity 10 is interrupted after the first control valve 71 is closed, while the vacuuming part 40 continues to evacuate the molding cavity 10, and the resin in the molding cavity 10 is pumped to one end close to the vacuuming part 40, while the end close to the first control valve 71 lacks resin, which is not conducive to the preparation of the molded part.

[0067] In one embodiment, after the molding cavity is infused with resin, the second control valve, the first control valve and the vacuum pumping part are opened for a preset time and then closed.

[0068] In this embodiment, when the molding cavity is filled with resin, the molding cavity is filled with resin, which means that the molding cavity is completely filled with resin. After the resin is filled, the second control valve, the first control valve and the vacuum unit are opened for a preset time, for example, 8-12 minutes, and the resin is continuously extracted to ensure that the amount of resin in the molding cavity is sufficient to avoid the problem of material shortage in the molding cavity. After 8-12 minutes of extraction, the second control valve, the first control valve and the vacuum unit can be closed to end the extraction of resin.

[0069] In one embodiment, after the resin is poured into the molding cavity and the second control valve, the first control valve and the vacuum pump are closed, the resin storage part, the first flow path and the second flow path can be taken out from the heating cavity to prevent the remaining resin in the resin storage part, the first flow path and the second flow path from being cured when the resin in the molding cavity is subsequently heated and cured. After the resin storage part, the first flow path and the second flow path are taken out from the heating cavity, the temperature of the heating cavity can be set to heat and cure the resin in the molding cavity to obtain a molded part.

[0070] The contents described above may be implemented individually or in combination in various ways, and these variations are all within the protection scope of the present disclosure.

[0071] Finally, it should be noted that in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes 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, article or apparatus.

[0072] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A vacuum forming device, characterized in that: include: A molding cavity, in which the preform is placed; A resin storage unit, used for containing resin; a first flow path, the resin storage portion is connected to the first end of the molding cavity through the first flow path, the first flow path includes a first branch and a second branch, a first control valve is provided between the first branch and the second branch, and the resin storage portion is connected to the first control valve through the first branch; Vacuuming unit; a second flow path, through which the vacuum pump is connected to the second end of the molding cavity, and a second control valve is provided on the second flow path; A heating chamber, wherein the molding chamber is placed in the heating chamber; The control unit is electrically connected to the vacuum pumping unit, the first control valve, and the second control valve. The control unit is used to control the first control valve, the second control valve, and the vacuum pumping unit so that after the first branch is filled with resin, the first control valve is closed and the vacuum pumping unit is controlled to vacuum the second branch, the molding cavity, and the second flow path, and the first control valve is opened after the vacuum pumping is completed to infuse the molding cavity with resin.

2. The vacuum forming device according to claim 1, characterized in that: The opening degree of the first control valve is adjustable; and / or the opening degree of the second control valve is adjustable.

3. The vacuum forming device according to claim 2, characterized in that: The first control valve comprises a two-way ball valve; and / or, The second control valve comprises a double-inserted ball valve.

4. The vacuum forming device according to any one of claims 1 to 3, characterized in that: The resin storage portion is placed in the heating chamber.

5. The vacuum forming device according to any one of claims 1 to 3, characterized in that: The vacuuming part is located outside the heating chamber.

6. A vacuum forming method, characterized in that: Using the vacuum forming device according to any one of claims 1 to 5, the vacuum forming method comprises: Opening the first control valve, the second control valve and the vacuum pumping unit to allow the resin in the resin storage unit to flow to the first branch pipe; When the resin fills the first branch pipe, closing the first control valve; When the pressure of the vacuuming part reaches a preset value, the first control valve is opened to inject the resin into the molding cavity through the first branch pipe and the second branch pipe; After the resin is poured into the molding cavity, the second control valve, the first control valve and the vacuum pumping part are closed.

7. The vacuum forming method according to claim 6, characterized in that: The opening of the first control valve includes: opening the first control valve to a preset opening, wherein the preset opening is smaller than a fully open opening of the first control valve.

8. The vacuum forming method according to claim 7, characterized in that: The preset opening is 1 / 5-1 / 2 of the full opening of the first control valve.

9. The vacuum forming method according to claim 6, characterized in that: The closing of the second control valve, the first control valve and the vacuum pumping part comprises: The second control valve, the first control valve, and the vacuum pumping unit are closed in sequence.

10. The vacuum forming method according to claim 6, characterized in that: After the resin is poured into the molding cavity, the second control valve, the first control valve and the vacuum pumping part are opened for a preset time and then closed.

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