A mold vacuum sealing system and sealing method

Abstract

The present invention relates to a mold vacuum sealing system and sealing method, including a pressure sensor, a vacuum oil cylinder, a control system, a vacuum pipeline and a vacuum pump; the pressure sensor is arranged in the mold cavity of the mold, and is used to collect the vacuum pressure value in the mold cavity of the mold, and feed it back to the control system; the vacuum oil cylinder is arranged at the junction of the mold cavity and the air path, and is used to control the connection state of the mold cavity and the air path; the control system is arranged outside the mold, one end of the control system is connected to the pressure sensor, and the other end is connected to the vacuum oil cylinder, and is used to receive the vacuum pressure value collected by the pressure sensor, and control the opening and closing of the vacuum oil cylinder. The present invention provides a mold vacuum sealing system and sealing method for extracting vacuum from the mold and maintaining the vacuum in the mold cavity. The pressure sensor is used to detect and control the action of the vacuum oil cylinder, and the vacuum degree in the mold cavity can be accurately controlled to improve the vacuum sealing performance in the mold cavity.

Description

Technical Field

[0001] The invention relates to the technical field of mold vacuum sealing, and in particular to a mold vacuum sealing system and a sealing method. Background Art

[0002] The high-pressure resin transfer molding (HP-RTM) process uses preforms to complete the resin infiltration and rapid curing through high-pressure injection, achieving large-scale, short-cycle, and high-quality production. The HP-RTM process uses a mixing head to inject the base resin into the mold, infiltrate the preformed fiber fabric, and finally quickly cure to form a high-strength composite component. The key technology of the HP-RTM process lies in the two stages of resin injection and molding: first, the preformed carbon fiber is placed in the mold of the press, and then the liquid resin is injected under high pressure.

[0003] At present, the vacuum degree in the mold cavity in the HP-RTM process directly affects the appearance and performance of the product. Insufficient vacuum degree in the mold leads to bubbles, pinholes, exposed fibers and other undesirable phenomena in the product. The sealing parts of the vacuum pumping and blowing cylinders of the existing molds are mostly sealed with a conical single sealing ring. The needle valve is directly installed in the mold. During the opening and closing process of the conical structure, foreign objects are easily dropped into it, resulting in poor sealing. The single-channel sealing ring will harden and fail due to resin infiltration. After long-term use, the contact part between the mold and the needle valve will wear, resulting in air leakage and even resin backflow. In addition, there are some fine fiber filaments in the mold cavity during the production process, which are easily sucked into the vacuum pipeline during the vacuum pumping process, causing problems such as wear of the sealing needle valve and damage to the vacuum pump.

[0004] Therefore, technical personnel in this field urgently need to provide a mold vacuum sealing system and sealing method for extracting vacuum from the mold and maintaining the vacuum in the mold cavity, accurately controlling the vacuum degree in the mold cavity, improving the vacuum sealing performance in the mold cavity, facilitating replacement and maintenance, and extending the service life. Summary of the invention

[0005] The purpose of the present invention is to provide a mold vacuum sealing system and a sealing method for extracting vacuum from the mold and maintaining the vacuum in the mold cavity, accurately controlling the vacuum degree in the mold cavity, improving the vacuum sealing performance in the mold cavity, facilitating replacement and maintenance, and extending the service life.

[0006] In order to achieve the above, the present invention provides a mold vacuum sealing system, the mold includes an upper mold and a lower mold, a mold cavity is provided between the upper mold and the lower mold, and an air path connected to the outside for vacuuming is provided on the mold, including:

[0007] A pressure sensor is disposed in the mold cavity of the mold, and is used to collect the vacuum pressure value in the mold cavity of the mold and feed it back to the control system.

[0008] A vacuum cylinder is provided at the junction of the mold cavity and the air path, and is used to control the connection state between the mold cavity and the air path; wherein the vacuum cylinder comprises a cylinder body, a needle valve and a sleeve, the sleeve is fixed on the mold, and has a vent hole connected to the air path, and the cylinder body is installed at the upper end of the needle valve, and is used to drive the needle valve to move up and down in the sleeve;

[0009] A control system is arranged outside the mold, one end of the control system is connected to the pressure sensor, and the other end is connected to the vacuum cylinder, for receiving the vacuum pressure value collected by the pressure sensor and controlling the opening and closing of the vacuum cylinder;

[0010] A vacuum pipeline, one end of which is connected to the gas circuit, and the other end of which is connected to the vacuum pump;

[0011] The vacuum pump is connected to the vacuum pipeline via a vacuum tank and is used to evacuate the mold cavity of the mold and reach a preset vacuum pressure value.

[0012] Preferably, the lower end of the needle valve has a toothed structure to prevent the fiber filaments from entering the vacuum pipeline through the air path.

[0013] Preferably, three sealing rings are provided on the needle valve.

[0014] Preferably, the mold is provided with a vacuum detection gauge for observing the vacuum pressure value in the mold cavity.

[0015] Preferably, the control system is connected to an injection molding machine, and when the control system detects that the vacuum cylinder is turned off, the control system controls the injection molding machine to turn on, so that the injection molding machine performs resin injection.

[0016] Preferably, the pressure sensor is connected to the control system via a signal line.

[0017] Preferably, a vacuum filter is provided on the vacuum pipeline to prevent fiber filaments from entering the vacuum pump.

[0018] Preferably, the sleeve is sealed by a sealing ring and a sealing gasket.

[0019] Preferably, the mold has an ejector rod, and two sealing grooves with sealing rings embedded therein are provided on the mold, and the sealing rings are used to seal the ejector rod.

[0020] The present invention also provides a sealing method for a mold vacuum sealing system, comprising the following steps:

[0021] S1. A sealing strip is embedded in the mold, and the upper mold and the lower mold are molded together and the sealing strip is pressed tightly to form a closed space in the mold cavity;

[0022] S2, open the vacuum cylinder and pull the needle valve to connect the mold cavity and the air path;

[0023] S3, turning on the vacuum pump, the vacuum pump replenishes the negative pressure of the vacuum tank, and the vacuum tank sucks out the gas in the mold cavity through the vacuum pipeline;

[0024] S4. The pressure sensor detects the vacuum pressure value in the mold cavity. When the vacuum pressure value in the mold cavity reaches a preset negative pressure value, it is fed back to the control system. The control system controls the vacuum cylinder, and the vacuum cylinder pushes the needle valve to disconnect the mold cavity and the air path, so that a constant negative pressure is maintained in the mold cavity.

[0025] S5. After the control system detects that the vacuum cylinder is closed, it controls the injection machine to start and the injection machine performs resin injection.

[0026] The mold vacuum sealing system and sealing method provided by the present invention have the following advantages:

[0027] (1) The present invention provides a mold vacuum sealing system and a sealing method for extracting vacuum from a mold and maintaining vacuum in a mold cavity. The pressure sensor is used to detect and control the action of the vacuum cylinder, thereby accurately controlling the vacuum degree in the mold cavity and improving the vacuum sealing performance in the mold cavity.

[0028] (2) The present invention provides three sealing rings at the needle valve of the vacuum oil cylinder, which realize the functions of the first sealing of glue, the second sealing of air, and the third extending the service life, thereby improving the vacuum degree in the mold cavity in the HP-RTM process, avoiding the occurrence of bubbles, pinholes, fiber exposure and other undesirable phenomena in the product, and improving the appearance and performance of the product;

[0029] (3) The present invention provides a sleeve structure between the needle valve and the mold, so that the seal can be quickly replaced after it is worn to a certain extent, avoiding returning to the factory for repair;

[0030] (4) The present invention has a toothed structure at the lower end of the needle valve to prevent the fiber filaments from entering the vacuum pipeline through the gas path. At the same time, a vacuum filter is provided on the vacuum pipeline to prevent the fiber filaments from entering the vacuum pump and causing damage to the pump body.

[0031] (5) The ejector pin adopts a double sealing ring design, which realizes the functions of the first sealing and the second sealing, greatly reducing the defect of the first sealing structure being corroded by the resin and hardening the sealing ring and causing failure, and reducing the replacement frequency of the sealing ring; at the same time, the sealing ring is installed on the mold side and does not follow the up and down movement of the ejector pin, which can maintain the sealing state in real time and reduce the damage to the sealing ring caused by the movement, thereby extending the service life of the sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A side view of the mold vacuum sealing system of the present invention;

[0033] Figure 2 It is a structural schematic diagram of the mold vacuum sealing system in the present invention;

[0034] Figure 3 It is a schematic diagram of the structure of the mold seal in the present invention;

[0035] Figure 4 for Figure 3 A partial enlarged view of the vacuum cylinder;

[0036] Figure 5 for Figure 4 A partial enlarged view of the middle needle valve;

[0037] Figure 6 It is a schematic structural diagram of the mold ejector in the present invention;

[0038] Figure 7 for Figure 6 A partial enlarged view of the sealing groove in the.

[0039] The reference numerals in the figure are:

[0040] Upper mold 100, lower mold 200, mold cavity 300, air circuit 310, pressure sensor 400, control system 500, vacuum cylinder 600, cylinder body 610, needle valve 620, tooth structure 621, sealing ring 622, sleeve 630, vacuum pipeline 700, vacuum pump 800, vacuum tank 900, vacuum detection gauge 1000, signal line 1100, vacuum filter 1200, ejector rod 1300, sealing groove 1400. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] Please see Figure 1-Figure 7 , Figure 1 A side view of the mold vacuum sealing system of the present invention; Figure 2 It is a structural schematic diagram of the mold vacuum sealing system in the present invention; Figure 3 It is a schematic diagram of the structure of the mold seal in the present invention; Figure 4 for Figure 3 A partial enlarged view of the vacuum cylinder; Figure 5 for Figure 4 A partial enlarged view of the middle needle valve; Figure 6 It is a schematic structural diagram of the mold ejector in the present invention; Figure 7 for Figure 6 A partial enlarged view of the sealing groove in the.

[0043] like Figure 1-5As shown, the present invention provides a mold vacuum sealing system, the mold includes an upper mold 100 and a lower mold 200, a mold cavity 300 is provided between the upper mold 100 and the lower mold 200, the mold is provided with an air path 310 connected to the outside for vacuuming, the mold vacuum sealing system includes a pressure sensor 400, a vacuum cylinder 600, a control system 500, a vacuum pipeline 700 and a vacuum pump 800.

[0044] Specifically, the pressure sensor 400 is disposed in the mold cavity 300 of the mold, and is used to collect the vacuum pressure value in the mold cavity 300 and feed it back to the control system 500 . The pressure sensor 400 is connected to the control system 500 via a signal line 1100 .

[0045] The vacuum cylinder 600 is arranged at the junction of the mold cavity 300 and the air circuit 310, and is used to control the connection state between the mold cavity 300 and the air circuit 310; wherein, the vacuum cylinder 600 includes a cylinder body 610, a needle valve 620 and a sleeve 630, the sleeve 630 is fixed on the mold, and the sleeve 630 has a vent hole connected to the air circuit 310, the cylinder body 610 is installed at the upper end of the needle valve 620, and is used to drive the needle valve 620 to move up and down in the sleeve 630.

[0046] like Figure 5 As shown, the lower end of the needle valve 620 has a tooth structure 621 to prevent the fiber filaments from entering the vacuum pipeline 700 through the air path; at the same time, a vacuum filter 1200 is provided on the vacuum pipeline 700 to prevent the fiber filaments from entering the vacuum pump 800 and causing damage to the pump body.

[0047] Three sealing rings 622 are arranged on the needle valve 620. By arranging three sealing rings 622 at the needle valve 620 of the vacuum cylinder, the first sealing is achieved, the second is sealed with gas, and the third is used to extend the service life. The vacuum degree in the mold cavity in the HP-RTM process is improved, and the product is prevented from having bubbles, pinholes, fiber exposure and other undesirable phenomena, thereby improving the appearance and performance of the product.

[0048] The sleeve 630 is sealed by a sealing ring and a sealing gasket. By providing a sleeve structure between the needle valve and the mold, the seal can be quickly replaced after being worn to a certain extent, avoiding return to the factory for repair.

[0049] The control system 500 is arranged outside the mold, one end of the control system is connected to the pressure sensor 400, and the other end is connected to the vacuum cylinder 600, for receiving the vacuum pressure value collected by the pressure sensor 400 and controlling the opening and closing of the vacuum cylinder 600. In addition, the control system 500 is also connected to the injection molding machine (not shown in the figure), and when the control system 500 detects that the vacuum cylinder is closed, it controls the injection molding machine to open and make the injection molding machine perform resin injection.

[0050] One end of the vacuum pipeline 700 is connected to the gas circuit 310, and the other end is connected to the vacuum pump 800; a vacuum filter 1200 is provided on the vacuum pipeline 700 to prevent fiber filaments from entering the vacuum pump 800, and the number of vacuum filters 1200 can be set according to needs.

[0051] The vacuum pump 800 is connected to the vacuum pipeline 700 through the vacuum tank 900, and is used to evacuate the mold cavity 300 of the mold and reach a preset vacuum pressure value. The vacuum pump 800 first evacuates the vacuum tank 900 and maintains the vacuum degree of the vacuum tank 900.

[0052] The mold may also be provided with a vacuum detection gauge 1000 for observing the vacuum pressure value in the mold cavity 300 .

[0053] like Figure 6-7 As shown, the mold has an ejector rod 1300, and two sealing grooves 1400 with sealing rings are provided on the mold, and the sealing rings are used to seal the ejector rod 1300. The ejector rod adopts a double sealing ring design, which realizes the functions of the first sealing and the second sealing, greatly reducing the defect of one sealing structure being corroded by resin and hardening the sealing ring and failing, and reducing the replacement frequency of the sealing ring; at the same time, the sealing ring is installed on the side of the mold and does not follow the up and down movement of the ejector rod, which can maintain the sealing state in real time and reduce the damage to the sealing ring caused by the movement, thereby extending the service life of the sealing ring.

[0054] The present invention also provides a sealing method for a mold vacuum sealing system, comprising the following steps:

[0055] S1. A sealing strip is embedded in the mold, and the upper mold 100 and the lower mold 200 are molded together and the sealing strip is pressed tightly to form a closed space in the mold cavity 300;

[0056] S2, start the vacuum cylinder 600, and pull the needle valve 620 to connect the mold cavity 300 and the gas path 310;

[0057] S3, turning on the vacuum pump 800, the vacuum pump 800 replenishes the negative pressure of the vacuum tank 900, and the vacuum tank 900 sucks out the gas in the mold cavity 300 through the vacuum pipeline 700;

[0058] S4, the pressure sensor 400 detects the vacuum pressure value in the mold cavity 300, and when the vacuum pressure value in the mold cavity 300 reaches a preset negative pressure value, the pressure sensor 400 feeds back to the control system 500, and the control system 500 controls the vacuum cylinder 600, and the vacuum cylinder 600 pushes the needle valve 620 to disconnect the mold cavity 300 and the air path 310, and maintain a constant negative pressure in the mold cavity 300;

[0059] S5. After the control system 500 detects that the vacuum cylinder 600 is turned off, it controls the injection machine to start, and the injection machine performs resin injection.

[0060] In summary, the present invention provides a mold vacuum sealing system and a sealing method for extracting vacuum from a mold and maintaining vacuum in a mold cavity. The pressure sensor is used to detect and control the action of the vacuum cylinder, so that the vacuum degree in the mold cavity can be accurately controlled, thereby improving the vacuum sealing performance in the mold cavity.

[0061] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the drawings. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the protection scope of the present invention.

Claims

1. A mold vacuum sealing system, the mold comprises an upper mold and a lower mold, a mold cavity is provided between the upper mold and the lower mold, and an air path connected to the outside for vacuuming is provided on the mold, characterized in that: include: The mold is provided with a vacuum detection gauge for observing the vacuum pressure value in the mold cavity of the mold; A pressure sensor is disposed in the mold cavity of the mold, and is used to collect the vacuum pressure value in the mold cavity of the mold and feed it back to the control system. A vacuum cylinder is provided at the junction of the mold cavity and the air path, and is used to control the connection state between the mold cavity and the air path; wherein the vacuum cylinder comprises a cylinder body, a needle valve and a sleeve, the sleeve is fixed on the mold, and has a vent hole connected to the air path, the cylinder body is installed at the upper end of the needle valve, and is used to drive the needle valve to move up and down in the sleeve; the lower end of the needle valve has a toothed structure to prevent the fiber filament from entering the vacuum pipeline through the air path; A control system is arranged outside the mold, one end of the control system is connected to the pressure sensor, and the other end is connected to the vacuum cylinder, for receiving the vacuum pressure value collected by the pressure sensor and controlling the opening and closing of the vacuum cylinder; A vacuum pipeline, one end of which is connected to the gas circuit, and the other end of which is connected to the vacuum pump; The vacuum pump is connected to the vacuum pipeline via a vacuum tank and is used to evacuate the mold cavity of the mold and reach a preset vacuum pressure value.

2. The mold vacuum sealing system according to claim 1, characterized in that: The needle valve is provided with three sealing rings.

3. The mold vacuum sealing system according to claim 1, characterized in that: The control system is connected to the injection machine. When the control system detects that the vacuum cylinder is closed, the control system controls the injection machine to be turned on so that the injection machine performs resin injection.

4. The mold vacuum sealing system according to claim 1, characterized in that: The pressure sensor is connected to the control system via a signal line.

5. The mold vacuum sealing system according to claim 1, characterized in that: A vacuum filter is provided on the vacuum pipeline to prevent fiber filaments from entering the vacuum pump.

6. The mold vacuum sealing system according to claim 1, characterized in that: The sleeve is sealed by a sealing ring and a sealing gasket.

7. The mold vacuum sealing system according to claim 1, characterized in that: The mold has an ejector rod, and two sealing grooves with sealing rings embedded therein are arranged on the mold. The sealing rings are used to seal the ejector rod.

8. A sealing method using the mold vacuum sealing system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. A sealing strip is embedded in the mold, and the upper mold and the lower mold are molded together and the sealing strip is pressed tightly to form a closed space in the mold cavity; S2, open the vacuum cylinder and pull the needle valve to connect the mold cavity and the air path; S3, turning on the vacuum pump, the vacuum pump replenishes the negative pressure of the vacuum tank, and the vacuum tank sucks out the gas in the mold cavity through the vacuum pipeline; S4. The pressure sensor detects the vacuum pressure value in the mold cavity. When the vacuum pressure value in the mold cavity reaches a preset negative pressure value, it is fed back to the control system. The control system controls the vacuum cylinder, and the vacuum cylinder pushes the needle valve to disconnect the mold cavity and the air path, so that a constant negative pressure is maintained in the mold cavity. S5. After the control system detects that the vacuum cylinder is closed, it controls the injection machine to start and the injection machine performs resin injection.

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