CN207643557U - RTM injection devices - Google Patents

Abstract

The utility model provides an RTM injection device, which includes an injection cylinder, a power system and an electrical numerical control system. The power system includes a servo motor and a hydraulic injection unit driven by the servo motor. The hydraulic injection unit includes a hydraulic piston extending into the injection cylinder; The electrical numerical control system includes a controller, a pressure sensor, and a displacement sensor. The pressure sensor is arranged on the injection cover of the injection cylinder for detecting the pressure in the injection cylinder to generate a pressure signal. The displacement sensor is arranged on the hydraulic piston for A displacement signal is generated, and the controller is configured to receive the pressure signal and the displacement signal, and thereby control the servo motor. The pressure of the injection liquid can be adjusted accurately and quickly according to the real-time pressure, so that the pressure can be precisely controlled and the long-term pressure holding stability can be obtained. At the same time, the injection amount of the resin can be accurately measured, which is conducive to improving the quality stability of the produced product. The equipment has simple structure and low cost, and can be widely used in scientific research and industrial production.

Description

RTM injection equipment

technical field

The utility model relates to an injection device, in particular to an RTM injection device.

Background technique

Since resin transfer molding (RTM) technology and lightweight RTM molding technology can not only make the parts smooth on both sides, the surface quality is good, the dimensional accuracy of the product is controllable, but also have a higher fiber volume fraction and mechanical properties, so the two This technology is very popular. The RTM molding process usually injects liquid resin into the mold under relatively high pressure (3-10bar), and heats and solidifies the molding. In order to ensure that the batch quality and surface quality of the product are controllable, the temperature, pressure and flow of the resin in the injection stage must be quantitatively controlled.

At present, the RTM injection equipment at home and abroad all use compressed air pneumatic or servo motor to drive the screw and piston to perform injection.

The pneumatic method refers to the use of compressed air (usually 3-7bar) to push the resin into the mold. The pneumatic method has the following disadvantages: the pneumatic power source fluctuates greatly, and the pressure is difficult to control stably. If the problem of the gas source is to be solved, a high-power compressor and a pressure buffer tank are required, which increases the complexity and floor space of the entire equipment; in addition Because of the high compressibility of the gas, the pressure feedback delay is large, and the response speed is low, it is difficult to accurately adjust the pressure value of the liquid injected into the mold according to the real-time pressure; compressed air will introduce air into the resin when pushing the resin to inject , resulting in defects that affect the mechanical properties and apparent quality of the product; the flow rate of resin injection is also difficult to accurately measure and control. At present, there are two types of flow measurement: volume or mass. The method of measuring quality is usually to install a gear flowmeter in the injection pipe. However, the characteristic of the RTM molding process is for parts with complex structures. The injection flow is generally low, about 50- 500ml/min, low-flow flowmeters are more expensive, and the resin is mixed with curing agent. If the operation is not done properly, there will be a risk of resin curing in the flowmeter. The method of volume measurement mainly uses a displacement sensor to measure the height of the resin liquid level drop to obtain the injection volume. The disadvantage of this method is that the resin injection flow rate is small, and the high-precision and small-range displacement sensor is expensive, and there is also a reaction speed. slow problem. Therefore, the current domestic and foreign equipment using this type of power cannot effectively measure the resin injection flow and accurately control the injection speed.

The specific technical principle of the servo motor driving the screw and the piston is that the bearing of the servo motor is connected with the screw through the feed screw connector to complete the stroke and displacement of the screw. The top of the screw is connected with the piston and the piston barrel, and the The injection material is poured into the piston barrel, and the injection flow and speed are controlled by controlling the rotation speed of the servo motor. Compared with the pneumatic power method, the servo motor drives the screw to drive the piston to run, but the manufacturing cost of the precision screw using this method is relatively high, and the stroke amount per minute needs to be accurately controlled. The minimum value is about 1mm Left and right, the mechanical wear of long-term work will affect the control accuracy. In addition, manual operation is required, and improper operation will cause deformation of the lead screw. If the injection cylinder is not cleaned or leaks, the injection material may remain on the thread of the lead screw, which will affect the operation of the lead screw. Another disadvantage is that the stability needs to be improved in the constant pressure and pressure maintaining stage of the RTM molding process. When the injection pressure reaches the set value, the servo motor stops working, and the lead screw also stops running synchronously. It stays at the current position, and the lead screw is affected by the liquid. Due to the back pressure effect, the stroke will move slowly, and the pressure of the liquid will gradually drop at the same time, the feedback speed of the servo motor receiving the pressure value is relatively slow, and it is difficult to restart the drive screw in time to stabilize the current pressure value.

Therefore, the power mode of the existing RTM injection equipment cannot guarantee the stability of the long-term operation of the equipment and the precise quantitative and constant pressure injection.

Utility model content

In order to solve the above technical problems, the purpose of this utility model is to provide an RTM injection device with a new type of power. The equipment is powered by a hydraulic system. The servo motor can efficiently control the speed and start-stop time of the hydraulic pump, realize the servo control of the flow and pressure of the hydraulic pump, and accurately and intelligently realize the digital control of the pressure, speed and position of the entire equipment.

The purpose of this utility model is achieved through the following technical solutions:

An RTM injection device, including a syringe, a power system and an electrical numerical control system, the power system includes a servo motor and a hydraulic injection unit driven by the servo motor, the hydraulic injection unit includes a hydraulic piston moving in the injection barrel; the electrical numerical control system includes a controller , a pressure sensor and a displacement sensor, the pressure sensor is arranged in the syringe for detecting the pressure in the syringe to generate a pressure signal, and the displacement sensor is arranged on the hydraulic piston to sense the stroke and position of the piston and generate a displacement signal , thereby accurately metering and controlling the resin injection volume, the controller is set to receive the pressure signal and the displacement signal, and control the servo motor according to the received signal.

Further, the electric numerical control system also includes a temperature sensor arranged in the injection barrel for generating a temperature signal. The controller receives the temperature signal, so that the electrical numerical control system can sense the temperature in the injection barrel in real time.

Further, it also includes a heating system for heating the injection cylinder, the controller controls the heating system, and performs heating in time according to the received temperature signal, so as to ensure the temperature of the resin in the injection cylinder.

Further, the pressure sensor is arranged on the injection cap of the injection cylinder.

Further, the hydraulic piston includes a piston head and a piston rod, and the piston head and the piston rod are connected to each other through a rotary bearing. In this way, the piston head can freely rotate relative to the piston rod. When the piston moves, the position can be fine-tuned through the free rotation of the piston head, so as to reduce the frictional force between the piston head and the inner wall of the syringe.

Further, the displacement sensor is arranged in the piston rod.

Furthermore, the piston head is in the shape of a truncated cone, which further reduces the friction between the piston head and the inner wall of the injection barrel.

Further, the RTM injection equipment injects the resin at a rate of 30 to 500ml/min.

Further, an automatic cleaning system is also included, and the automatic cleaning system includes a reversing valve arranged on the injection cap, and the reversing valve is set to switch between the compressed air supply and the vacuum pipeline system. The vacuum pipeline system can also be used for vacuuming and defoaming the resin in the injection cylinder.

Further, an operation panel is also included, the operation panel displays the signal received by the controller, and the controller can be manipulated through the operation panel. On the one hand, the operation panel displays real-time data, and on the other hand, the controller can be manipulated by inputting preset values on the operation panel.

Beneficial effects of utility model

The utility model adopts the power mode of hydraulic injection driven by a servo motor, combined with the numerical control sensing of temperature, displacement, pressure, etc., and can accurately and quickly adjust the pressure of the injection liquid according to the real-time pressure, so as to precisely control the pressure and obtain good long-term maintenance. Pressure stability, and at the same time, it can accurately measure the injection amount of resin, which is conducive to improving the quality and batch stability of the produced products. The equipment of the utility model has simple structure and low overall cost, and can be widely used in scientific research and industrial production.

Description of drawings

Fig. 1 is the schematic diagram of RTM injection equipment;

Figure 2 is a schematic diagram of the RTM injection equipment taking off the equipment cover to expose the injection barrel;

Fig. 3 is the schematic diagram of syringe;

Fig. 4 is the schematic diagram of hydraulic piston;

Fig. 5 is a schematic diagram of the utility model;

Fig. 6 is the circuit diagram of the present utility model;

in:

1 syringe

2 hydraulic pistons

3 Swivel bearings

4 piston head

5 piston rod

6 pressure sensor

7 Displacement sensor

8 temperature sensor

9 Injection cap

10 Operation panel

11 Reversing valve

12 oil pump

13 fuel tank

14 air cooler

15 relief valve

16 Solenoid overflow valve

17 Servo motor

18 check valve

19 oil cylinder

20 pressure gauge

Detailed ways

Referring to FIGS. 1-5 , the RTM injection equipment in the embodiment includes an injection cylinder 1 , a power system, an electrical numerical control system, a heating system and an operation panel 10 . The power system 1 includes a servo motor 17 and a hydraulic injection unit driven by the servo motor 17, the hydraulic injection unit includes a hydraulic piston 2 moving in the injection barrel, and the hydraulic piston 2 includes a piston head 4 and a piston rod connected to each other through a rotary bearing 3 5. The piston head is in the shape of a truncated cone. The electrical numerical control system is used to control the power system and the heating system, which includes a controller (not shown), a pressure sensor 6 , a displacement sensor 7 and a temperature sensor 8 . Wherein the pressure sensor 6 is arranged on the injection cover 9 of the injection cylinder 1, and is used to detect the pressure in the injection cylinder to generate a pressure signal, and the injection cover 9 is connected and sealed with the cylinder body by bolts; the displacement sensor 7 is arranged on the piston of the hydraulic piston 2 The rod 5 is used to generate the displacement signal of the piston; the controller is set to receive the pressure signal, displacement signal and temperature signal, and control the servo motor and heating system according to the received signal. The signal received by the controller is displayed on the operation panel 10, and the operation panel can perform direct input operation, and the controller can be manipulated through the operation panel.

The RTM injection equipment also includes an automatic cleaning system, which includes a reversing valve 11 arranged on the injection cap 9, and the reversing valve 11 is arranged to switch between the compressed air supply and the vacuum pipeline system.

In this embodiment, the technical parameters set by the RTM injection equipment are as follows:

(1) Upper limit of injection pressure: 10bar;

(2) Resin injection speed: 30-500ml/min;

(3) Resin injection temperature: room temperature -100°C, temperature control accuracy ±3°C;

(4) Resin vacuum degassing pressure: -1bar-0;

(5) Injection tank capacity: inner diameter 140mm, height 500mm, about 7.7L;

The injection equipment adopts 220V one-way power supply, the total design power is 2.5KW, the overall size is 1100mm (length) * 600mm (width) * 1600mm (height), the total weight of the equipment is about 600Kg, and the equipment is equipped with pulleys for easy transportation.

Referring to FIG. 4 , the working principle of the RTM injection device of the present application is: start the device, and set the stroke position of the piston on the operation panel 10 . Open the injection cap 9 on the syringe 1, and put the injection material into the syringe 1. Adjust the reversing valve 11 to connect the syringe 1 with a vacuum pipeline system (not shown), and perform vacuum degassing treatment on the resin. The heating temperature and time are set on the operation panel 10, and the heating system is started to heat the syringe 1. At the same time, the pressure, flow rate, injection time, flow rate, etc. of different injection sections are set separately. The servo motor 17 starts to work, drives the oil pump 12 to rotate, and injects the hydraulic oil in the oil tank 13 into the piston rod 5 through the reversing valve 11, so that the piston 2 moves upward slowly, and the hydraulic oil is cooled by the air cooler 14 to prevent overheating. While the piston 2 is moving, the displacement sensor 7 inside the piston rod 5 records the current piston position and cylinder injection volume online, and at the same time, the pressure sensor displays the current injection resin pressure. When the resin enters the mold through the pipeline (not shown) of the injection cap, the pressure sensor 6 on the injection cap 9 receives pressure feedback, the injection flow rate Q1 is displayed on the operation panel 10, the injection time t1 starts, the injection time t2 ends, and synchronization Display the pressure P1 of the pressure sensor and the position d2 of the piston. There are two ways to stop at this stage: the first is to stop automatically when P1 reaches the upper limit pressure value P set in this stage, and the second is to stop manually. At the same time, the reversing valve 11, the overflow valve 15 and the electromagnetic overflow valve 16 are opened to work, and the hydraulic oil is reversely overflowed back to the oil tank 13, and the pressure gauge 20 is installed on the overflow valve to display the actual pressure value of the hydraulic oil. Entering the next constant-pressure-holding injection stage, according to the holding pressure P2 and pressure-holding time set on the operation panel 10, the equipment will automatically run, and then continue to increase the pressure-holding injection until the injection process is completed. In the pressure holding stage, due to the reaction pressure of the hydraulic cylinder, the piston will gradually move down, and the pressure value will drop. After reaching the set value of the lower limit of the pressure, the servo motor 17 will start again, and the hydraulic oil will be injected into the piston rod 5 through the check valve 18 , thereby again controlling the movement of the piston.

It should be understood that the above-mentioned embodiments of the present utility model are only examples for clearly illustrating the present utility model, rather than limiting the implementation manner of the present utility model. For those skilled in the art, on the basis of the above description, other changes or changes in different forms can also be made. All the implementation manners cannot be exhaustively listed here. All obvious changes or changes derived from the technical solutions of the utility model are still within the scope of protection of the utility model.

Claims (9)

1.RTM injection devices, which is characterized in that including injection tube, dynamical system and electrical digital control system, the dynamical system packet The hydraulic injection unit of servo motor and servo motor driving is included, the hydraulic injection unit includes in the injection tube The hydraulic piston of movement；The electrical digital control system includes controller, pressure sensor and displacement sensor, the pressure sensing Device is arranged in the injection tube, for detecting the pressure in injection tube to generate pressure signal, institute's displacement sensors setting On the hydraulic piston, for generating displacement signal, the controller is set as receiving the pressure signal and the displacement Signal, and the servo motor is controlled according to received signal.

2. RTM injection devices according to claim 1, the electrical digital control system further includes the temperature being arranged in injection tube Sensor is spent, for generating temperature signal.

3. RTM injection devices according to claim 1 further include the heating system for heating the injection tube, described Controller controls the heating system.

4. RTM injection devices according to claim 1, the injection lid in the injection tube is arranged in the pressure sensor On.

5. RTM injection devices according to claim 1, the hydraulic piston includes piston head and piston rod, the piston Head and the piston rod are connected with each other by swivel bearing.

6. RTM injection devices according to claim 5, institute's displacement sensors are arranged in the piston rod.

7. RTM injection devices according to claim 5, the piston head is taper type.

8. RTM injection devices according to claim 1, further include automatic cleaning system, the automatic cleaning system includes The reversal valve covered in injection is set, and the reversal valve is set as switching between compressed air confession gives vacuum line system.

9. the RTM injection devices according to any one of claim 1-8, further include operation panel, the operation panel is aobvious Show the controller received signal, and the controller can be manipulated by the operation panel.