Two-component RTM (Resin Transfer Molding) injection machine

Abstract

The utility model discloses a two-component RTM (Resin Transfer Molding) injection machine, which belongs to the technical field of composite material production and comprises a component A tank body, a component B tank body, a mixed glue injection unit, vacuum pumps respectively used for vacuumizing the tank bodies, and two groups of feeding units used for conveying materials in the tank bodies to the mixed glue injection unit, each feeding unit comprises two plunger barrels, pistons arranged in the plunger barrels in a sealed mode and a servo driver for driving the pistons to move in the axial direction of the plunger barrels, and the bottoms of the plunger barrels communicate with feeding pipes and discharging pipes. Feeding pipes of the two plunger barrels of the same feeding unit are connected to the outlet end of the bottom of the A component tank body or the outlet end of the bottom of the B component tank body in parallel, discharging pipes of the two plunger barrels of the same feeding unit are connected to any inlet end of the mixed glue injection unit in parallel, and one-way valves for limiting reverse conveying of materials are installed on the feeding pipes and the discharging pipes. According to the utility model, the requirements of high precision, high pressure and high reserves during composite material forming are met.

Description

Technical Field

[0001] This utility model relates to the field of composite material production technology, and in particular to a two-component RTM injection molding machine. Background Technology

[0002] In composite material production, a two-component RTM injection molding machine is used to deliver and mix two components, such as resin and curing agent, and then inject them into the mold to achieve material curing and molding within the mold.

[0003] Existing two-component RTM injection molding machines in China typically use gear pumps for delivery to achieve precise mixing of the two components in the correct proportions. However, when using gear pumps for resin delivery, the leakage rate is related to the resin viscosity. That is, when delivering low-viscosity resins, the leakage rate of the gear pump increases, which in turn reduces the accuracy of mixing low-viscosity resins. At the same time, due to the limitations of the gear pump's own structure, its outlet pressure can usually only be maintained within 3MPa, which cannot meet the requirements of high-pressure products (10-15MPa) in the mixer, thus limiting the use of two-component RTM injection molding machines. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a two-component RTM injection molding machine that can adapt to the feeding requirements of resins with different viscosities and the injection requirements of high-pressure products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A two-component RTM injection molding machine includes an A-component tank, a B-component tank, a mixing and dispensing unit, two sets of vacuum pumps for evacuating the A-component tank and the B-component tank respectively, and two sets of feeding units for conveying materials from the A-component tank and the B-component tank to the mixing and dispensing unit respectively. Each feeding unit includes two plunger cylinders, a piston sealed inside each plunger cylinder, and a servo driver for driving each piston to move axially along the plunger cylinder. The bottom of each plunger cylinder is connected to an inlet pipe and an outlet pipe. The inlet pipes of the two plunger cylinders of the same feeding unit are connected in parallel to the outlet ends of the bottom of the A-component tank / B-component tank, and the outlet pipes of the two plunger cylinders of the same feeding unit are connected in parallel to any inlet end of the mixing and dispensing unit. One-way valves that restrict reverse material conveying are installed on the inlet pipe and the outlet pipe. By setting two sets of parallel plunger cylinders at the outlet ends of the A-component tank and the B-component tank respectively, and driving the pistons in the plunger cylinders to reciprocate, the materials of A-component and B-component are continuously conveyed from the tanks to the mixing and dispensing unit. Compared with the gear pump in the prior art, the piston-pushing sealed conveying method is not affected by the resin viscosity, ensuring that the injection molding machine has a sufficiently high metering accuracy. Furthermore, under the drive of the servo driver, the piston can generate a sufficiently large pressure on the material in the plunger cylinder to meet the high-pressure product requirements in the mixing and dispensing unit.

[0007] The servo driver is a servo electric cylinder, which includes a cylinder body and a servo motor for adjusting the speed of the ball screw inside the cylinder body. The front frame of the cylinder body is fixedly connected to the top opening of the plunger cylinder, and the output shaft of the cylinder body is fixedly connected to the piston.

[0008] The servo driver is a servo hydraulic cylinder, which includes a hydraulic cylinder body and a servo valve for adjusting the oil flow rate inside the hydraulic cylinder body. The front frame of the hydraulic cylinder body is fixedly connected to the top opening of the plunger cylinder, and the output shaft of the hydraulic cylinder body is fixedly connected to the piston.

[0009] Valves controlling the opening and closing of the pipeline are installed on the feed pipe and the discharge pipe. An additional valve is installed on one side of the check valve. When the check valve is performing its backflow prevention function, the valve on the same pipeline is closed to reduce the burden caused by the reverse pressure generated in the plunger cylinder on the check valve of the pipeline, and effectively prevent material leakage at the check valve.

[0010] It includes a control unit, each of the servo drivers and each of the vacuum pumps, which are communicatively connected to the control unit.

[0011] The valves are solenoid valves, and each solenoid valve is communicatively connected to the control unit. The control unit alternately controls the servo driver and the solenoid valves on the corresponding pipelines within the same feeding unit, thereby achieving continuous feeding of the corresponding tank.

[0012] An electromagnetic flow meter is installed on the discharge pipe at the inlet end of the mixing and dispensing unit, and the electromagnetic flow meter is communicatively connected to the control unit.

[0013] A pressure sensor for monitoring the pressure inside the plunger cylinder is installed on the plunger cylinder, and the pressure sensor is communicatively connected to the control unit.

[0014] The mixing and dispensing unit includes a T-joint and a static mixer. Two ports of the T-joint form the inlet of the mixing and dispensing unit, and the other port of the T-joint is connected to the inlet of the static mixer. The static mixer uses its built-in spiral blades to shear and mix the two components entering the mixer, improving the mixing uniformity of the two components.

[0015] This utility model has the following beneficial effects:

[0016] This invention features two sets of parallel plunger cylinders installed at the outlets of the A-component tank and the B-component tank, respectively. A servo driver drives the pistons inside the plunger cylinders to reciprocate, enabling continuous delivery of A-component and B-component materials from the tanks to the mixing and dispensing unit. Compared to gear pumps in the prior art, this piston-push sealed delivery method is unaffected by resin viscosity, ensuring that the injection molding machine has sufficiently high metering accuracy. Furthermore, under the drive of the servo driver, the piston can generate sufficient pressure on the material inside the plunger cylinder to meet the high-pressure product requirements of the mixing and dispensing unit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a connection diagram of the present invention;

[0019] Figure 2 This is a schematic diagram showing the connection of the same group of feeding units in this utility model;

[0020] Figure 3 This is a cross-sectional schematic diagram of the servo electric cylinder in Example 1;

[0021] Figure 4 This is a schematic diagram of the servo hydraulic cylinder in Example 2;

[0022] Figure 5 This is a cross-sectional schematic diagram of the mixing and dispensing unit in this utility model.

[0023] 1. Component A tank; 2. Component B tank; 3. Vacuum pump; 4. Feeding unit; 401. Servo driver; 402. Plunger cylinder; 403. Piston; 404. Servo motor; 405. Electric cylinder body; 4051. Gearbox; 4052. Guide frame; 406. Drive parachute wheel; 407. Transmission parachute wheel; 408. Ball screw; 4081. Slider; 409. Servo valve; 410. Hydraulic cylinder body; 5. Feed pipe; 6. Discharge pipe; 7. Check valve; 8. Mixing and dispensing unit; 801. T-connector; 802. Static mixer; 9. Solenoid valve; 10. Control unit; 11. Electromagnetic flow meter; 12. Pressure sensor. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] like Figure 1As shown, this utility model provides a two-component RTM injection molding machine, including a component A tank 1, a component B tank 2, a mixing and dispensing unit 8, two sets of vacuum pumps 3 for evacuating the component A tank 1 and the component B tank 2 respectively, and two sets of feeding units 4 for conveying the materials in the component A tank 1 and the component B tank 2 to the mixing and dispensing unit 8 respectively. Figure 2 As shown, each of the feeding units 4 includes two plunger cylinders 402, a piston 403 sealed inside each plunger cylinder 402, and a servo driver 401 that drives each piston 403 to move axially along the plunger cylinder 402. Each plunger cylinder 402 has an inlet pipe 5 and an outlet pipe 6 connected to its bottom. The inlet pipes 5 of the two plunger cylinders 402 of the same feeding unit 4 are connected in parallel to the outlet end of the bottom of the A component tank 1 / B component tank 2. The outlet pipes 6 of the two plunger cylinders 402 of the same feeding unit 4 are connected in parallel to any inlet end of the mixing and dispensing unit 8. One-way valves 7 that restrict reverse material conveying are installed on the inlet pipe 5 and the outlet pipe 6. In embodiment 1, as shown... Figure 3 As shown, the servo driver 401 is a servo electric cylinder. The servo electric cylinder includes a cylinder body 405 and a servo motor 404 that adjusts the speed of the ball screw 408 inside the cylinder body 405. The front end frame of the cylinder body 405 is fixedly connected to the top opening of the plunger cylinder 402, and the output shaft of the cylinder body 405 is fixedly connected to the piston 403. Specifically, this embodiment provides one structure of the servo electric cylinder. The cylinder body includes a reduction gearbox 4051 and a guide frame 4052 connected sequentially in a direction away from the plunger cylinder 402. The front end of the ball screw 408 serves as the output shaft of the cylinder body 405 and is fixedly connected to the piston 403. The end of the ball screw 408 passes through the reduction gearbox 4051 and slides with the inner side of the guide frame 4052 via a slider 4081. The servo motor 404 is fixed on the outside of the gearbox 4051, and the output shaft of the servo motor 404 passes through the gearbox 4051 and is connected to the drive parachute wheel 406. The ball screw 408 is sleeved on the outside and has a transmission parachute wheel 407 that meshes with the drive parachute wheel 406. The inner side of the transmission parachute wheel 407 is threaded with the ball screw 408. The outer end of the transmission parachute wheel 407 is rotatably connected to the gearbox 4051 via a thrust bearing. The servo motor 404 drives the transmission parachute wheel 407 to rotate through the drive parachute wheel 406. With the joint cooperation of the guide frame 4052 and the internal thread of the transmission parachute wheel 407, the drive ball screw 408 and the piston 403 move axially together in the plunger cylinder 402 to complete the feeding action of the feeding unit 4 to the mixing and dispensing unit 8 or the suction action to the tank.

[0029] In Example 2, as Figure 4As shown, the servo driver 401 is a servo hydraulic cylinder, which includes a hydraulic cylinder body 410 and a servo valve 409 for adjusting the oil inlet of the hydraulic cylinder body 410. The front end frame of the hydraulic cylinder body 410 is fixedly connected to the top opening of the plunger cylinder 402. The output shaft of the hydraulic cylinder body 410 is fixedly connected to the piston 403. The opening of the servo valve 409 is controlled by the electronic control module to adjust the oil inlet of the servo valve 409, thereby adjusting the axial movement speed of the output shaft in the hydraulic cylinder body 410 to precisely control the feeding amount of each plunger cylinder 102.

[0030] One-way valves 7 are installed on the feed pipe 5 and discharge pipe 6 of the plunger cylinder 402 to ensure that when one piston 403 cooperates with the plunger cylinder 402 to perform feeding / suction actions in the same feeding unit 4, it does not affect the other plunger cylinder 402. The two plunger cylinders 402 in the same feeding unit 4 alternately complete the feeding action to ensure the continuous delivery of each component material from the tank to the mixing and dispensing unit 8. The piston 403 push-type feeding method is not affected by the resin viscosity in terms of sealing performance compared with the gear pump in the prior art, so that the injection machine has a sufficiently high metering accuracy. Furthermore, under the drive of various servo drives 401, the piston 403 can generate sufficient pressure on the material in the plunger cylinder 402, thereby meeting the high-pressure product requirements in the mixing and dispensing unit 8.

[0031] like Figure 5 As shown, the mixing and dispensing unit 8 in this embodiment includes a three-way connector 801 and a static mixer 802. Two of the interfaces of the three-way connector 801 form the inlet end of the mixing and dispensing unit 8, and the other interface of the three-way connector 801 is connected to the inlet of the static mixer 802. The static mixer 802 is provided in the mixing and dispensing unit 8. The two components entering the mixer are sheared and mixed by the spiral blades built into the mixer, thereby improving the mixing uniformity of the two components.

[0032] To reduce the reverse pressure on the check valve 7 on the feed pipe 5 / discharge pipe 6 caused by the forward / backward movement of the piston 403 within the plunger cylinder 402, and to minimize the risk of leakage from the check valve 7, such as... Figure 1 As shown, valves controlling the opening and closing of the pipeline are installed on the feed pipe 5 and the discharge pipe 6. When the check valve 7 performs its anti-reverse function, the valves on the same pipeline are closed to protect the check valve 7.

[0033] To improve the automation level of injection molding machines, such as Figure 1As shown, this injection molding machine also includes a control unit 10. Specifically, the control unit 10 is a PLC controller. The PLC controller is existing technology, and its control principle will not be described in detail here. Each of the servo drives 401 (servo motor 404 in the servo electric cylinder / servo valve 409 in the servo hydraulic cylinder) and each of the vacuum pumps 3 are communicatively connected to the control unit 10. Preferably, the valves are solenoid valves 9, and each of the solenoid valves 9 is communicatively connected to the control unit 10. The control unit 10 alternately controls the servo drives 401 in the same feeding unit 4 and the solenoid valves 9 on the corresponding pipelines to automatically realize the continuous feeding of the corresponding tank.

[0034] To further improve the accuracy of metering, an electromagnetic flow meter 11 is installed on the discharge pipe 6 at the inlet end of the mixing and dispensing unit 8. The electromagnetic flow meter 11 is communicatively connected to the control unit 10 and records the amount of A and B components added to the mixing and dispensing unit 8.

[0035] More preferably, a pressure sensor 12 for monitoring the pressure inside the plunger cylinder 402 is installed on the plunger cylinder 402, and the pressure sensor 12 is communicatively connected to the control unit 10.

[0036] Taking Example 1 as an example, when implementing this technical solution, the resin required for molding the composite material is added to component A tank 1, and the corresponding curing agent is added to component B tank 2. The control unit 10 controls the vacuum pump 3 to perform a vacuum operation on component A tank 1 and component B tank 2 to remove gas from the adhesive. The servo motor 404 on the outside of one of the plunger cylinders 402 connected to the outlet of component A tank 1 is controlled to rotate forward and open the solenoid valve 9 on the feed pipe 5 of the plunger cylinder 402. The servo motor 404 on the outside of one of the plunger cylinders 402 connected to the outlet of component B tank 2 is controlled to rotate forward and open the solenoid valve 9 on the feed pipe 5 of the plunger cylinder 402. The piston 403 is moved backward to complete the feeding action of components A and B. Each servo motor 404 rotates forward to its rated speed and then stops. At this time, the piston 403 reaches the specified position, and the plunger cylinder 402 corresponding to different components draws in the rated volume of material. The servo motor 404 on the outside of the plunger cylinder 402 that has drawn in material is controlled to rotate in reverse, while the solenoid valve 9 on the feed pipe 5 is closed and the solenoid valve 9 on the discharge pipe 6 is opened, completing the feeding action of components A and B. At the same time, the servo motor 404 on the outside of the other plunger cylinder 402 connected to the outlet of component A tank 1 is controlled to rotate forward and the solenoid valve 9 on the feed pipe 5 of the plunger cylinder 402 is opened, controlling the feeding action of components B. The servo motor 404 on the outside of another plunger cylinder 402 connected to the outlet of tank 2 rotates forward and opens the solenoid valve 9 on the feed pipe 5 of the plunger cylinder 402, completing the material suction action of the other plunger cylinder 402 in the same feeding unit 4. After sucking in the same rated volume of material, the servo motor 404 and the solenoid valve 9 on the feed pipe 5 are closed, and the system is in a ready-to-feed state. When feeding components A and B, in order to achieve different proportions of mixing between components A and B, the control unit 10 sets different speed values ​​for the servo motor 404 corresponding to tank 1 of component A and the servo motor 404 corresponding to tank 2 of component B during the feeding action, that is, under the same parameters. If the required mixing ratio of AB is 10:1, then the speed ratio of the corresponding servo motor 404 is set to 10:1. When the servo motor 404 corresponding to component A tank 1 / component B tank 2 reverses to the rated speed and then stops, the plunger cylinder 402 is emptied. At the same time, the servo motor 404 on the other plunger cylinder 402 in the same feeding unit 4 is controlled to reverse and the solenoid valve 9 of the discharge pipe 6 on the plunger cylinder 402 is opened to complete the continuous feeding operation. Meanwhile, the emptied plunger cylinder 402 continues to suck up material and enters the next preparation state. This cycle repeats, meeting the requirements of high precision, high pressure and high storage capacity required for composite material molding.

[0037] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A two-component RTM injection molding machine, comprising a component A tank, a component B tank, a mixing and dispensing unit, two sets of vacuum pumps for evacuating the component A tank and the component B tank respectively, and two sets of feeding units for conveying materials from the component A tank and the component B tank to the mixing and dispensing unit respectively, characterized in that, Each of the feeding units includes two plunger cylinders, a piston sealed inside each plunger cylinder, and a servo driver that drives each piston to move axially along the plunger cylinder. The bottom of each plunger cylinder is connected to an inlet pipe and an outlet pipe. The inlet pipes of the two plunger cylinders of the same feeding unit are connected in parallel to the outlet end of the bottom of the A component tank / B component tank. The outlet pipes of the two plunger cylinders of the same feeding unit are connected in parallel to any inlet end of the mixing and dispensing unit. One-way valves that restrict the reverse conveying of materials are installed on the inlet pipe and the outlet pipe.

2. The two-component RTM injection machine according to claim 1, characterized in that, The servo driver is a servo electric cylinder, which includes a cylinder body and a servo motor for adjusting the speed of the ball screw inside the cylinder body. The front frame of the cylinder body is fixedly connected to the top opening of the plunger cylinder, and the output shaft of the cylinder body is fixedly connected to the piston.

3. The two-component RTM injection machine according to claim 1, characterized in that, The servo driver is a servo hydraulic cylinder, which includes a hydraulic cylinder body and a servo valve for adjusting the oil flow rate inside the hydraulic cylinder body. The front frame of the hydraulic cylinder body is fixedly connected to the top opening of the plunger cylinder, and the output shaft of the hydraulic cylinder body is fixedly connected to the piston.

4. The two-component RTM injection machine according to any one of claims 1-3, characterized in that, It includes a control unit, each of the servo drivers and each of the vacuum pumps, which are communicatively connected to the control unit.

5. The two-component RTM injection machine according to claim 4, characterized in that, The feed pipe and the discharge pipe are equipped with valves to control the opening and closing of the pipeline.

6. The two-component RTM injection machine according to claim 5, characterized in that, The valves are solenoid valves, and each solenoid valve is communicatively connected to the control unit.

7. The two-component RTM injection machine according to claim 4, characterized in that, An electromagnetic flow meter is installed on the discharge pipe at the inlet end of the mixing and dispensing unit, and the electromagnetic flow meter is communicatively connected to the control unit.

8. The two-component RTM injection machine according to claim 4, characterized in that, A pressure sensor for monitoring the pressure inside the plunger cylinder is installed on the plunger cylinder, and the pressure sensor is communicatively connected to the control unit.

9. The two-component RTM injection machine according to claim 4, characterized in that, The mixing and dispensing unit includes a tee connector and a static mixer. Two of the tee connector's ports form the inlet end of the mixing and dispensing unit, and the other port of the tee connector is connected to the inlet of the static mixer.

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